gccrs: Add HIR to GCC GENERIC lowering for all nodes

This patch implements the lowering mentioned in the previous patch for all HIR nodes.

	gcc/rust/
	* backend/rust-compile-block.cc: New.
	* backend/rust-compile-block.h: New.
	* backend/rust-compile-expr.cc: New.
	* backend/rust-compile-expr.h: New.
	* backend/rust-compile-extern.h: New.
	* backend/rust-compile-fnparam.cc: New.
	* backend/rust-compile-fnparam.h: New.
	* backend/rust-compile-implitem.cc: New.
	* backend/rust-compile-implitem.h: New.
	* backend/rust-compile-intrinsic.cc: New.
	* backend/rust-compile-intrinsic.h: New.
	* backend/rust-compile-item.cc: New.
	* backend/rust-compile-item.h: New.
	* backend/rust-compile-pattern.cc: New.
	* backend/rust-compile-pattern.h: New.
	* backend/rust-compile-resolve-path.cc: New.
	* backend/rust-compile-resolve-path.h: New.
	* backend/rust-compile-stmt.cc: New.
	* backend/rust-compile-stmt.h: New.
	* backend/rust-compile-struct-field-expr.cc: New.
	* backend/rust-compile-struct-field-expr.h: New.
	* backend/rust-compile-type.cc: New.
	* backend/rust-compile-type.h: New.
	* backend/rust-compile-var-decl.h: New.

Co-authored-by: David Faust <david.faust@oracle.com>

24 files changed, 6690 insertions, 0 deletions

diff --git a/gcc/rust/backend/rust-compile-block.cc b/gcc/rust/backend/rust-compile-block.cc
new file mode 100644
index 00000000000..99674e2d1e7
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-block.cc
@@ -0,0 +1,158 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-compile-block.h"
+#include "rust-compile-stmt.h"
+#include "rust-compile-expr.h"
+
+namespace Rust {
+namespace Compile {
+
+CompileBlock::CompileBlock (Context *ctx, Bvariable *result)
+  : HIRCompileBase (ctx), translated (nullptr), result (result)
+{}
+
+tree
+CompileBlock::compile (HIR::BlockExpr *expr, Context *ctx, Bvariable *result)
+{
+  CompileBlock compiler (ctx, result);
+  compiler.visit (*expr);
+  return compiler.translated;
+}
+
+void
+CompileBlock::visit (HIR::BlockExpr &expr)
+{
+  fncontext fnctx = ctx->peek_fn ();
+  tree fndecl = fnctx.fndecl;
+  Location start_location = expr.get_locus ();
+  Location end_location = expr.get_end_locus ();
+  auto body_mappings = expr.get_mappings ();
+
+  Resolver::Rib *rib = nullptr;
+  if (!ctx->get_resolver ()->find_name_rib (body_mappings.get_nodeid (), &rib))
+    {
+      rust_fatal_error (expr.get_locus (), "failed to setup locals per block");
+      return;
+    }
+
+  std::vector<Bvariable *> locals
+    = compile_locals_for_block (ctx, *rib, fndecl);
+
+  tree enclosing_scope = ctx->peek_enclosing_scope ();
+  tree new_block = ctx->get_backend ()->block (fndecl, enclosing_scope, locals,
+					       start_location, end_location);
+  ctx->push_block (new_block);
+
+  for (auto &s : expr.get_statements ())
+    {
+      auto compiled_expr = CompileStmt::Compile (s.get (), ctx);
+      if (compiled_expr != nullptr)
+	{
+	  tree s = convert_to_void (compiled_expr, ICV_STATEMENT);
+	  ctx->add_statement (s);
+	}
+    }
+
+  if (expr.has_expr ())
+    {
+      // the previous passes will ensure this is a valid return or
+      // a valid trailing expression
+      tree compiled_expr = CompileExpr::Compile (expr.expr.get (), ctx);
+      if (compiled_expr != nullptr)
+	{
+	  if (result == nullptr)
+	    {
+	      ctx->add_statement (compiled_expr);
+	    }
+	  else
+	    {
+	      tree result_reference = ctx->get_backend ()->var_expression (
+		result, expr.get_final_expr ()->get_locus ());
+
+	      tree assignment
+		= ctx->get_backend ()->assignment_statement (result_reference,
+							     compiled_expr,
+							     expr.get_locus ());
+	      ctx->add_statement (assignment);
+	    }
+	}
+    }
+
+  ctx->pop_block ();
+  translated = new_block;
+}
+
+void
+CompileConditionalBlocks::visit (HIR::IfExpr &expr)
+{
+  fncontext fnctx = ctx->peek_fn ();
+  tree fndecl = fnctx.fndecl;
+  tree condition_expr = CompileExpr::Compile (expr.get_if_condition (), ctx);
+  tree then_block = CompileBlock::compile (expr.get_if_block (), ctx, result);
+
+  translated
+    = ctx->get_backend ()->if_statement (fndecl, condition_expr, then_block,
+					 NULL, expr.get_locus ());
+}
+
+void
+CompileConditionalBlocks::visit (HIR::IfExprConseqElse &expr)
+{
+  fncontext fnctx = ctx->peek_fn ();
+  tree fndecl = fnctx.fndecl;
+  tree condition_expr = CompileExpr::Compile (expr.get_if_condition (), ctx);
+  tree then_block = CompileBlock::compile (expr.get_if_block (), ctx, result);
+  tree else_block = CompileBlock::compile (expr.get_else_block (), ctx, result);
+
+  translated
+    = ctx->get_backend ()->if_statement (fndecl, condition_expr, then_block,
+					 else_block, expr.get_locus ());
+}
+
+void
+CompileConditionalBlocks::visit (HIR::IfExprConseqIf &expr)
+{
+  fncontext fnctx = ctx->peek_fn ();
+  tree fndecl = fnctx.fndecl;
+  tree condition_expr = CompileExpr::Compile (expr.get_if_condition (), ctx);
+  tree then_block = CompileBlock::compile (expr.get_if_block (), ctx, result);
+
+  // else block
+  std::vector<Bvariable *> locals;
+  Location start_location = expr.get_conseq_if_expr ()->get_locus ();
+  Location end_location = expr.get_conseq_if_expr ()->get_locus (); // FIXME
+  tree enclosing_scope = ctx->peek_enclosing_scope ();
+  tree else_block = ctx->get_backend ()->block (fndecl, enclosing_scope, locals,
+						start_location, end_location);
+  ctx->push_block (else_block);
+
+  tree else_stmt_decl
+    = CompileConditionalBlocks::compile (expr.get_conseq_if_expr (), ctx,
+					 result);
+  ctx->add_statement (else_stmt_decl);
+
+  ctx->pop_block ();
+
+  translated
+    = ctx->get_backend ()->if_statement (fndecl, condition_expr, then_block,
+					 else_block, expr.get_locus ());
+}
+
+} // namespace Compile
+} // namespace Rust
diff --git a/gcc/rust/backend/rust-compile-block.h b/gcc/rust/backend/rust-compile-block.h
new file mode 100644
index 00000000000..cdd17f19ca2
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-block.h
@@ -0,0 +1,211 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_COMPILE_BLOCK
+#define RUST_COMPILE_BLOCK
+
+#include "rust-compile-base.h"
+
+namespace Rust {
+namespace Compile {
+
+class CompileBlock : private HIRCompileBase
+{
+public:
+  static tree compile (HIR::BlockExpr *expr, Context *ctx, Bvariable *result);
+
+protected:
+  void visit (HIR::BlockExpr &expr);
+
+private:
+  CompileBlock (Context *ctx, Bvariable *result);
+
+  tree translated;
+  Bvariable *result;
+};
+
+class CompileConditionalBlocks : public HIRCompileBase,
+				 public HIR::HIRExpressionVisitor
+{
+public:
+  static tree compile (HIR::IfExpr *expr, Context *ctx, Bvariable *result)
+  {
+    CompileConditionalBlocks resolver (ctx, result);
+    expr->accept_vis (resolver);
+    return resolver.translated;
+  }
+
+  void visit (HIR::IfExpr &expr) override;
+  void visit (HIR::IfExprConseqElse &expr) override;
+  void visit (HIR::IfExprConseqIf &expr) override;
+
+  // Empty visit for unused Expression HIR nodes.
+  void visit (HIR::PathInExpression &) override {}
+  void visit (HIR::QualifiedPathInExpression &) override {}
+  void visit (HIR::ClosureExprInner &) override {}
+  void visit (HIR::ClosureExprInnerTyped &) override {}
+  void visit (HIR::StructExprFieldIdentifier &) override {}
+  void visit (HIR::StructExprFieldIdentifierValue &) override {}
+  void visit (HIR::StructExprFieldIndexValue &) override {}
+  void visit (HIR::StructExprStruct &) override {}
+  void visit (HIR::StructExprStructFields &) override {}
+  void visit (HIR::LiteralExpr &) override {}
+  void visit (HIR::BorrowExpr &) override {}
+  void visit (HIR::DereferenceExpr &) override {}
+  void visit (HIR::ErrorPropagationExpr &) override {}
+  void visit (HIR::NegationExpr &) override {}
+  void visit (HIR::ArithmeticOrLogicalExpr &) override {}
+  void visit (HIR::ComparisonExpr &) override {}
+  void visit (HIR::LazyBooleanExpr &) override {}
+  void visit (HIR::TypeCastExpr &) override {}
+  void visit (HIR::AssignmentExpr &) override {}
+  void visit (HIR::CompoundAssignmentExpr &) override {}
+  void visit (HIR::GroupedExpr &) override {}
+  void visit (HIR::ArrayExpr &) override {}
+  void visit (HIR::ArrayIndexExpr &) override {}
+  void visit (HIR::TupleExpr &) override {}
+  void visit (HIR::TupleIndexExpr &) override {}
+  void visit (HIR::CallExpr &) override {}
+  void visit (HIR::MethodCallExpr &) override {}
+  void visit (HIR::FieldAccessExpr &) override {}
+  void visit (HIR::BlockExpr &) override {}
+  void visit (HIR::ContinueExpr &) override {}
+  void visit (HIR::BreakExpr &) override {}
+  void visit (HIR::RangeFromToExpr &) override {}
+  void visit (HIR::RangeFromExpr &) override {}
+  void visit (HIR::RangeToExpr &) override {}
+  void visit (HIR::RangeFullExpr &) override {}
+  void visit (HIR::RangeFromToInclExpr &) override {}
+  void visit (HIR::RangeToInclExpr &) override {}
+  void visit (HIR::ReturnExpr &) override {}
+  void visit (HIR::UnsafeBlockExpr &) override {}
+  void visit (HIR::LoopExpr &) override {}
+  void visit (HIR::WhileLoopExpr &) override {}
+  void visit (HIR::WhileLetLoopExpr &) override {}
+  void visit (HIR::ForLoopExpr &) override {}
+  void visit (HIR::IfExprConseqIfLet &) override {}
+  void visit (HIR::IfLetExpr &) override {}
+  void visit (HIR::IfLetExprConseqElse &) override {}
+  void visit (HIR::IfLetExprConseqIf &) override {}
+  void visit (HIR::IfLetExprConseqIfLet &) override {}
+  void visit (HIR::MatchExpr &) override {}
+  void visit (HIR::AwaitExpr &) override {}
+  void visit (HIR::AsyncBlockExpr &) override {}
+
+private:
+  CompileConditionalBlocks (Context *ctx, Bvariable *result)
+    : HIRCompileBase (ctx), translated (nullptr), result (result)
+  {}
+
+  tree translated;
+  Bvariable *result;
+};
+
+class CompileExprWithBlock : public HIRCompileBase,
+			     public HIR::HIRExpressionVisitor
+{
+public:
+  static tree compile (HIR::ExprWithBlock *expr, Context *ctx,
+		       Bvariable *result)
+  {
+    CompileExprWithBlock resolver (ctx, result);
+    expr->accept_vis (resolver);
+    return resolver.translated;
+  }
+
+  void visit (HIR::IfExpr &expr) override
+  {
+    translated = CompileConditionalBlocks::compile (&expr, ctx, result);
+  }
+
+  void visit (HIR::IfExprConseqElse &expr) override
+  {
+    translated = CompileConditionalBlocks::compile (&expr, ctx, result);
+  }
+
+  void visit (HIR::IfExprConseqIf &expr) override
+  {
+    translated = CompileConditionalBlocks::compile (&expr, ctx, result);
+  }
+
+  // Empty visit for unused Expression HIR nodes.
+  void visit (HIR::PathInExpression &) override {}
+  void visit (HIR::QualifiedPathInExpression &) override {}
+  void visit (HIR::ClosureExprInner &) override {}
+  void visit (HIR::ClosureExprInnerTyped &) override {}
+  void visit (HIR::StructExprFieldIdentifier &) override {}
+  void visit (HIR::StructExprFieldIdentifierValue &) override {}
+  void visit (HIR::StructExprFieldIndexValue &) override {}
+  void visit (HIR::StructExprStruct &) override {}
+  void visit (HIR::StructExprStructFields &) override {}
+  void visit (HIR::LiteralExpr &) override {}
+  void visit (HIR::BorrowExpr &) override {}
+  void visit (HIR::DereferenceExpr &) override {}
+  void visit (HIR::ErrorPropagationExpr &) override {}
+  void visit (HIR::NegationExpr &) override {}
+  void visit (HIR::ArithmeticOrLogicalExpr &) override {}
+  void visit (HIR::ComparisonExpr &) override {}
+  void visit (HIR::LazyBooleanExpr &) override {}
+  void visit (HIR::TypeCastExpr &) override {}
+  void visit (HIR::AssignmentExpr &) override {}
+  void visit (HIR::CompoundAssignmentExpr &) override {}
+  void visit (HIR::GroupedExpr &) override {}
+  void visit (HIR::ArrayExpr &) override {}
+  void visit (HIR::ArrayIndexExpr &) override {}
+  void visit (HIR::TupleExpr &) override {}
+  void visit (HIR::TupleIndexExpr &) override {}
+  void visit (HIR::CallExpr &) override {}
+  void visit (HIR::MethodCallExpr &) override {}
+  void visit (HIR::FieldAccessExpr &) override {}
+  void visit (HIR::BlockExpr &) override {}
+  void visit (HIR::ContinueExpr &) override {}
+  void visit (HIR::BreakExpr &) override {}
+  void visit (HIR::RangeFromToExpr &) override {}
+  void visit (HIR::RangeFromExpr &) override {}
+  void visit (HIR::RangeToExpr &) override {}
+  void visit (HIR::RangeFullExpr &) override {}
+  void visit (HIR::RangeFromToInclExpr &) override {}
+  void visit (HIR::RangeToInclExpr &) override {}
+  void visit (HIR::ReturnExpr &) override {}
+  void visit (HIR::UnsafeBlockExpr &) override {}
+  void visit (HIR::LoopExpr &) override {}
+  void visit (HIR::WhileLoopExpr &) override {}
+  void visit (HIR::WhileLetLoopExpr &) override {}
+  void visit (HIR::ForLoopExpr &) override {}
+  void visit (HIR::IfExprConseqIfLet &) override {}
+  void visit (HIR::IfLetExpr &) override {}
+  void visit (HIR::IfLetExprConseqElse &) override {}
+  void visit (HIR::IfLetExprConseqIf &) override {}
+  void visit (HIR::IfLetExprConseqIfLet &) override {}
+  void visit (HIR::MatchExpr &) override {}
+  void visit (HIR::AwaitExpr &) override {}
+  void visit (HIR::AsyncBlockExpr &) override {}
+
+private:
+  CompileExprWithBlock (Context *ctx, Bvariable *result)
+    : HIRCompileBase (ctx), translated (nullptr), result (result)
+  {}
+
+  tree translated;
+  Bvariable *result;
+};
+
+} // namespace Compile
+} // namespace Rust
+
+#endif // RUST_COMPILE_BLOCK
diff --git a/gcc/rust/backend/rust-compile-expr.cc b/gcc/rust/backend/rust-compile-expr.cc
new file mode 100644
index 00000000000..8d239e92f45
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-expr.cc
@@ -0,0 +1,2769 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-compile-expr.h"
+#include "rust-compile-struct-field-expr.h"
+#include "rust-hir-trait-resolve.h"
+#include "rust-hir-path-probe.h"
+#include "rust-hir-type-bounds.h"
+#include "rust-compile-pattern.h"
+#include "rust-compile-resolve-path.h"
+#include "rust-compile-block.h"
+#include "rust-compile-implitem.h"
+#include "rust-constexpr.h"
+
+#include "fold-const.h"
+#include "realmpfr.h"
+#include "convert.h"
+#include "print-tree.h"
+
+namespace Rust {
+namespace Compile {
+
+CompileExpr::CompileExpr (Context *ctx)
+  : HIRCompileBase (ctx), translated (error_mark_node)
+{}
+
+tree
+CompileExpr::Compile (HIR::Expr *expr, Context *ctx)
+{
+  CompileExpr compiler (ctx);
+  expr->accept_vis (compiler);
+  return compiler.translated;
+}
+
+void
+CompileExpr::visit (HIR::TupleIndexExpr &expr)
+{
+  HIR::Expr *tuple_expr = expr.get_tuple_expr ().get ();
+  TupleIndex index = expr.get_tuple_index ();
+
+  tree receiver_ref = CompileExpr::Compile (tuple_expr, ctx);
+
+  TyTy::BaseType *tuple_expr_ty = nullptr;
+  bool ok
+    = ctx->get_tyctx ()->lookup_type (tuple_expr->get_mappings ().get_hirid (),
+				      &tuple_expr_ty);
+  rust_assert (ok);
+
+  // do we need to add an indirect reference
+  if (tuple_expr_ty->get_kind () == TyTy::TypeKind::REF)
+    {
+      tree indirect = indirect_expression (receiver_ref, expr.get_locus ());
+      receiver_ref = indirect;
+    }
+
+  translated
+    = ctx->get_backend ()->struct_field_expression (receiver_ref, index,
+						    expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::TupleExpr &expr)
+{
+  if (expr.is_unit ())
+    {
+      translated = ctx->get_backend ()->unit_expression ();
+      return;
+    }
+
+  TyTy::BaseType *tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (),
+				       &tyty))
+    {
+      rust_fatal_error (expr.get_locus (),
+			"did not resolve type for this TupleExpr");
+      return;
+    }
+
+  tree tuple_type = TyTyResolveCompile::compile (ctx, tyty);
+  rust_assert (tuple_type != nullptr);
+
+  // this assumes all fields are in order from type resolution
+  std::vector<tree> vals;
+  for (auto &elem : expr.get_tuple_elems ())
+    {
+      auto e = CompileExpr::Compile (elem.get (), ctx);
+      vals.push_back (e);
+    }
+
+  translated
+    = ctx->get_backend ()->constructor_expression (tuple_type, false, vals, -1,
+						   expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::ReturnExpr &expr)
+{
+  auto fncontext = ctx->peek_fn ();
+
+  std::vector<tree> retstmts;
+  if (expr.has_return_expr ())
+    {
+      tree compiled_expr = CompileExpr::Compile (expr.return_expr.get (), ctx);
+      rust_assert (compiled_expr != nullptr);
+
+      retstmts.push_back (compiled_expr);
+    }
+
+  auto s = ctx->get_backend ()->return_statement (fncontext.fndecl, retstmts,
+						  expr.get_locus ());
+  ctx->add_statement (s);
+}
+
+void
+CompileExpr::visit (HIR::ArithmeticOrLogicalExpr &expr)
+{
+  auto op = expr.get_expr_type ();
+  auto lhs = CompileExpr::Compile (expr.get_lhs (), ctx);
+  auto rhs = CompileExpr::Compile (expr.get_rhs (), ctx);
+
+  // this might be an operator overload situation lets check
+  TyTy::FnType *fntype;
+  bool is_op_overload = ctx->get_tyctx ()->lookup_operator_overload (
+    expr.get_mappings ().get_hirid (), &fntype);
+  if (is_op_overload)
+    {
+      auto lang_item_type
+	= Analysis::RustLangItem::OperatorToLangItem (expr.get_expr_type ());
+      translated = resolve_operator_overload (lang_item_type, expr, lhs, rhs,
+					      expr.get_lhs (), expr.get_rhs ());
+      return;
+    }
+
+  translated
+    = ctx->get_backend ()->arithmetic_or_logical_expression (op, lhs, rhs,
+							     expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::CompoundAssignmentExpr &expr)
+{
+  auto op = expr.get_expr_type ();
+  auto lhs = CompileExpr::Compile (expr.get_left_expr ().get (), ctx);
+  auto rhs = CompileExpr::Compile (expr.get_right_expr ().get (), ctx);
+
+  // this might be an operator overload situation lets check
+  TyTy::FnType *fntype;
+  bool is_op_overload = ctx->get_tyctx ()->lookup_operator_overload (
+    expr.get_mappings ().get_hirid (), &fntype);
+  if (is_op_overload)
+    {
+      auto lang_item_type
+	= Analysis::RustLangItem::CompoundAssignmentOperatorToLangItem (
+	  expr.get_expr_type ());
+      auto compound_assignment
+	= resolve_operator_overload (lang_item_type, expr, lhs, rhs,
+				     expr.get_left_expr ().get (),
+				     expr.get_right_expr ().get ());
+      ctx->add_statement (compound_assignment);
+
+      return;
+    }
+
+  auto operator_expr
+    = ctx->get_backend ()->arithmetic_or_logical_expression (op, lhs, rhs,
+							     expr.get_locus ());
+  tree assignment
+    = ctx->get_backend ()->assignment_statement (lhs, operator_expr,
+						 expr.get_locus ());
+  ctx->add_statement (assignment);
+}
+
+void
+CompileExpr::visit (HIR::NegationExpr &expr)
+{
+  auto op = expr.get_expr_type ();
+  auto negated_expr = CompileExpr::Compile (expr.get_expr ().get (), ctx);
+  auto location = expr.get_locus ();
+
+  // this might be an operator overload situation lets check
+  TyTy::FnType *fntype;
+  bool is_op_overload = ctx->get_tyctx ()->lookup_operator_overload (
+    expr.get_mappings ().get_hirid (), &fntype);
+  if (is_op_overload)
+    {
+      auto lang_item_type
+	= Analysis::RustLangItem::NegationOperatorToLangItem (op);
+      translated
+	= resolve_operator_overload (lang_item_type, expr, negated_expr,
+				     nullptr, expr.get_expr ().get (), nullptr);
+      return;
+    }
+
+  translated
+    = ctx->get_backend ()->negation_expression (op, negated_expr, location);
+}
+
+void
+CompileExpr::visit (HIR::ComparisonExpr &expr)
+{
+  auto op = expr.get_expr_type ();
+  auto lhs = CompileExpr::Compile (expr.get_lhs (), ctx);
+  auto rhs = CompileExpr::Compile (expr.get_rhs (), ctx);
+  auto location = expr.get_locus ();
+
+  translated
+    = ctx->get_backend ()->comparison_expression (op, lhs, rhs, location);
+}
+
+void
+CompileExpr::visit (HIR::LazyBooleanExpr &expr)
+{
+  auto op = expr.get_expr_type ();
+  auto lhs = CompileExpr::Compile (expr.get_lhs (), ctx);
+  auto rhs = CompileExpr::Compile (expr.get_rhs (), ctx);
+  auto location = expr.get_locus ();
+
+  translated
+    = ctx->get_backend ()->lazy_boolean_expression (op, lhs, rhs, location);
+}
+
+void
+CompileExpr::visit (HIR::TypeCastExpr &expr)
+{
+  TyTy::BaseType *type_to_cast_to_ty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (),
+				       &type_to_cast_to_ty))
+    {
+      translated = error_mark_node;
+      return;
+    }
+
+  TyTy::BaseType *casted_tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (
+	expr.get_casted_expr ()->get_mappings ().get_hirid (), &casted_tyty))
+    {
+      translated = error_mark_node;
+      return;
+    }
+
+  auto type_to_cast_to = TyTyResolveCompile::compile (ctx, type_to_cast_to_ty);
+  auto casted_expr = CompileExpr::Compile (expr.get_casted_expr ().get (), ctx);
+
+  std::vector<Resolver::Adjustment> *adjustments = nullptr;
+  bool ok = ctx->get_tyctx ()->lookup_cast_autoderef_mappings (
+    expr.get_mappings ().get_hirid (), &adjustments);
+  if (ok)
+    {
+      casted_expr
+	= resolve_adjustements (*adjustments, casted_expr, expr.get_locus ());
+    }
+
+  translated
+    = type_cast_expression (type_to_cast_to, casted_expr, expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::IfExpr &expr)
+{
+  auto stmt = CompileConditionalBlocks::compile (&expr, ctx, nullptr);
+  ctx->add_statement (stmt);
+}
+
+void
+CompileExpr::visit (HIR::IfExprConseqElse &expr)
+{
+  TyTy::BaseType *if_type = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (),
+				       &if_type))
+    {
+      rust_error_at (expr.get_locus (),
+		     "failed to lookup type of IfExprConseqElse");
+      return;
+    }
+
+  Bvariable *tmp = NULL;
+  bool needs_temp = !if_type->is_unit ();
+  if (needs_temp)
+    {
+      fncontext fnctx = ctx->peek_fn ();
+      tree enclosing_scope = ctx->peek_enclosing_scope ();
+      tree block_type = TyTyResolveCompile::compile (ctx, if_type);
+
+      bool is_address_taken = false;
+      tree ret_var_stmt = nullptr;
+      tmp = ctx->get_backend ()->temporary_variable (
+	fnctx.fndecl, enclosing_scope, block_type, NULL, is_address_taken,
+	expr.get_locus (), &ret_var_stmt);
+      ctx->add_statement (ret_var_stmt);
+    }
+
+  auto stmt = CompileConditionalBlocks::compile (&expr, ctx, tmp);
+  ctx->add_statement (stmt);
+
+  if (tmp != NULL)
+    {
+      translated = ctx->get_backend ()->var_expression (tmp, expr.get_locus ());
+    }
+}
+
+void
+CompileExpr::visit (HIR::IfExprConseqIf &expr)
+{
+  TyTy::BaseType *if_type = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (),
+				       &if_type))
+    {
+      rust_error_at (expr.get_locus (),
+		     "failed to lookup type of IfExprConseqElse");
+      return;
+    }
+
+  Bvariable *tmp = NULL;
+  bool needs_temp = !if_type->is_unit ();
+  if (needs_temp)
+    {
+      fncontext fnctx = ctx->peek_fn ();
+      tree enclosing_scope = ctx->peek_enclosing_scope ();
+      tree block_type = TyTyResolveCompile::compile (ctx, if_type);
+
+      bool is_address_taken = false;
+      tree ret_var_stmt = nullptr;
+      tmp = ctx->get_backend ()->temporary_variable (
+	fnctx.fndecl, enclosing_scope, block_type, NULL, is_address_taken,
+	expr.get_locus (), &ret_var_stmt);
+      ctx->add_statement (ret_var_stmt);
+    }
+
+  auto stmt = CompileConditionalBlocks::compile (&expr, ctx, tmp);
+  ctx->add_statement (stmt);
+
+  if (tmp != NULL)
+    {
+      translated = ctx->get_backend ()->var_expression (tmp, expr.get_locus ());
+    }
+}
+
+void
+CompileExpr::visit (HIR::BlockExpr &expr)
+{
+  TyTy::BaseType *block_tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (),
+				       &block_tyty))
+    {
+      rust_error_at (expr.get_locus (), "failed to lookup type of BlockExpr");
+      return;
+    }
+
+  Bvariable *tmp = NULL;
+  bool needs_temp = !block_tyty->is_unit ();
+  if (needs_temp)
+    {
+      fncontext fnctx = ctx->peek_fn ();
+      tree enclosing_scope = ctx->peek_enclosing_scope ();
+      tree block_type = TyTyResolveCompile::compile (ctx, block_tyty);
+
+      bool is_address_taken = false;
+      tree ret_var_stmt = nullptr;
+      tmp = ctx->get_backend ()->temporary_variable (
+	fnctx.fndecl, enclosing_scope, block_type, NULL, is_address_taken,
+	expr.get_locus (), &ret_var_stmt);
+      ctx->add_statement (ret_var_stmt);
+    }
+
+  auto block_stmt = CompileBlock::compile (&expr, ctx, tmp);
+  rust_assert (TREE_CODE (block_stmt) == BIND_EXPR);
+  ctx->add_statement (block_stmt);
+
+  if (tmp != NULL)
+    {
+      translated = ctx->get_backend ()->var_expression (tmp, expr.get_locus ());
+    }
+}
+
+void
+CompileExpr::visit (HIR::UnsafeBlockExpr &expr)
+{
+  expr.get_block_expr ()->accept_vis (*this);
+}
+
+void
+CompileExpr::visit (HIR::StructExprStruct &struct_expr)
+{
+  TyTy::BaseType *tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (struct_expr.get_mappings ().get_hirid (),
+				       &tyty))
+    {
+      rust_error_at (struct_expr.get_locus (), "unknown type");
+      return;
+    }
+
+  rust_assert (tyty->is_unit ());
+  translated = ctx->get_backend ()->unit_expression ();
+}
+
+void
+CompileExpr::visit (HIR::StructExprStructFields &struct_expr)
+{
+  TyTy::BaseType *tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (struct_expr.get_mappings ().get_hirid (),
+				       &tyty))
+    {
+      rust_error_at (struct_expr.get_locus (), "unknown type");
+      return;
+    }
+
+  // it must be an ADT
+  rust_assert (tyty->get_kind () == TyTy::TypeKind::ADT);
+  TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (tyty);
+
+  // what variant is it?
+  int union_disriminator = struct_expr.union_index;
+  TyTy::VariantDef *variant = nullptr;
+  if (!adt->is_enum ())
+    {
+      rust_assert (adt->number_of_variants () == 1);
+      variant = adt->get_variants ().at (0);
+    }
+  else
+    {
+      HirId variant_id;
+      bool ok = ctx->get_tyctx ()->lookup_variant_definition (
+	struct_expr.get_struct_name ().get_mappings ().get_hirid (),
+	&variant_id);
+      rust_assert (ok);
+
+      ok
+	= adt->lookup_variant_by_id (variant_id, &variant, &union_disriminator);
+      rust_assert (ok);
+    }
+
+  // compile it
+  tree compiled_adt_type = TyTyResolveCompile::compile (ctx, tyty);
+
+  std::vector<tree> arguments;
+  if (adt->is_union ())
+    {
+      rust_assert (struct_expr.get_fields ().size () == 1);
+
+      // assignments are coercion sites so lets convert the rvalue if
+      // necessary
+      auto respective_field = variant->get_field_at_index (union_disriminator);
+      auto expected = respective_field->get_field_type ();
+
+      // process arguments
+      auto &argument = struct_expr.get_fields ().at (0);
+      auto lvalue_locus
+	= ctx->get_mappings ()->lookup_location (expected->get_ty_ref ());
+      auto rvalue_locus = argument->get_locus ();
+      auto rvalue = CompileStructExprField::Compile (argument.get (), ctx);
+
+      TyTy::BaseType *actual = nullptr;
+      bool ok = ctx->get_tyctx ()->lookup_type (
+	argument->get_mappings ().get_hirid (), &actual);
+
+      if (ok)
+	{
+	  rvalue
+	    = coercion_site (argument->get_mappings ().get_hirid (), rvalue,
+			     actual, expected, lvalue_locus, rvalue_locus);
+	}
+
+      // add it to the list
+      arguments.push_back (rvalue);
+    }
+  else
+    {
+      // this assumes all fields are in order from type resolution and if a
+      // base struct was specified those fields are filed via accesors
+      for (size_t i = 0; i < struct_expr.get_fields ().size (); i++)
+	{
+	  // assignments are coercion sites so lets convert the rvalue if
+	  // necessary
+	  auto respective_field = variant->get_field_at_index (i);
+	  auto expected = respective_field->get_field_type ();
+
+	  // process arguments
+	  auto &argument = struct_expr.get_fields ().at (i);
+	  auto lvalue_locus
+	    = ctx->get_mappings ()->lookup_location (expected->get_ty_ref ());
+	  auto rvalue_locus = argument->get_locus ();
+	  auto rvalue = CompileStructExprField::Compile (argument.get (), ctx);
+
+	  TyTy::BaseType *actual = nullptr;
+	  bool ok = ctx->get_tyctx ()->lookup_type (
+	    argument->get_mappings ().get_hirid (), &actual);
+
+	  // coerce it if required/possible see
+	  // compile/torture/struct_base_init_1.rs
+	  if (ok)
+	    {
+	      rvalue
+		= coercion_site (argument->get_mappings ().get_hirid (), rvalue,
+				 actual, expected, lvalue_locus, rvalue_locus);
+	    }
+
+	  // add it to the list
+	  arguments.push_back (rvalue);
+	}
+    }
+
+  // the constructor depends on whether this is actually an enum or not if
+  // its an enum we need to setup the discriminator
+  std::vector<tree> ctor_arguments;
+  if (adt->is_enum ())
+    {
+      HIR::Expr *discrim_expr = variant->get_discriminant ();
+      tree discrim_expr_node = CompileExpr::Compile (discrim_expr, ctx);
+      tree folded_discrim_expr = fold_expr (discrim_expr_node);
+      tree qualifier = folded_discrim_expr;
+
+      ctor_arguments.push_back (qualifier);
+    }
+  for (auto &arg : arguments)
+    ctor_arguments.push_back (arg);
+
+  translated = ctx->get_backend ()->constructor_expression (
+    compiled_adt_type, adt->is_enum (), ctor_arguments, union_disriminator,
+    struct_expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::GroupedExpr &expr)
+{
+  translated = CompileExpr::Compile (expr.get_expr_in_parens ().get (), ctx);
+}
+
+void
+CompileExpr::visit (HIR::FieldAccessExpr &expr)
+{
+  HIR::Expr *receiver_expr = expr.get_receiver_expr ().get ();
+  tree receiver_ref = CompileExpr::Compile (receiver_expr, ctx);
+
+  // resolve the receiver back to ADT type
+  TyTy::BaseType *receiver = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (
+	expr.get_receiver_expr ()->get_mappings ().get_hirid (), &receiver))
+    {
+      rust_error_at (expr.get_receiver_expr ()->get_locus (),
+		     "unresolved type for receiver");
+      return;
+    }
+
+  size_t field_index = 0;
+  if (receiver->get_kind () == TyTy::TypeKind::ADT)
+    {
+      TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (receiver);
+      rust_assert (!adt->is_enum ());
+      rust_assert (adt->number_of_variants () == 1);
+
+      TyTy::VariantDef *variant = adt->get_variants ().at (0);
+      bool ok
+	= variant->lookup_field (expr.get_field_name (), nullptr, &field_index);
+      rust_assert (ok);
+    }
+  else if (receiver->get_kind () == TyTy::TypeKind::REF)
+    {
+      TyTy::ReferenceType *r = static_cast<TyTy::ReferenceType *> (receiver);
+      TyTy::BaseType *b = r->get_base ();
+      rust_assert (b->get_kind () == TyTy::TypeKind::ADT);
+
+      TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (b);
+      rust_assert (!adt->is_enum ());
+      rust_assert (adt->number_of_variants () == 1);
+
+      TyTy::VariantDef *variant = adt->get_variants ().at (0);
+      bool ok
+	= variant->lookup_field (expr.get_field_name (), nullptr, &field_index);
+      rust_assert (ok);
+
+      tree indirect = indirect_expression (receiver_ref, expr.get_locus ());
+      receiver_ref = indirect;
+    }
+
+  translated
+    = ctx->get_backend ()->struct_field_expression (receiver_ref, field_index,
+						    expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::QualifiedPathInExpression &expr)
+{
+  translated = ResolvePathRef::Compile (expr, ctx);
+}
+
+void
+CompileExpr::visit (HIR::PathInExpression &expr)
+{
+  translated = ResolvePathRef::Compile (expr, ctx);
+}
+
+void
+CompileExpr::visit (HIR::LoopExpr &expr)
+{
+  TyTy::BaseType *block_tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (),
+				       &block_tyty))
+    {
+      rust_error_at (expr.get_locus (), "failed to lookup type of BlockExpr");
+      return;
+    }
+
+  fncontext fnctx = ctx->peek_fn ();
+  tree enclosing_scope = ctx->peek_enclosing_scope ();
+  tree block_type = TyTyResolveCompile::compile (ctx, block_tyty);
+
+  bool is_address_taken = false;
+  tree ret_var_stmt = NULL_TREE;
+  Bvariable *tmp = ctx->get_backend ()->temporary_variable (
+    fnctx.fndecl, enclosing_scope, block_type, NULL, is_address_taken,
+    expr.get_locus (), &ret_var_stmt);
+  ctx->add_statement (ret_var_stmt);
+  ctx->push_loop_context (tmp);
+
+  if (expr.has_loop_label ())
+    {
+      HIR::LoopLabel &loop_label = expr.get_loop_label ();
+      tree label
+	= ctx->get_backend ()->label (fnctx.fndecl,
+				      loop_label.get_lifetime ().get_name (),
+				      loop_label.get_locus ());
+      tree label_decl = ctx->get_backend ()->label_definition_statement (label);
+      ctx->add_statement (label_decl);
+      ctx->insert_label_decl (
+	loop_label.get_lifetime ().get_mappings ().get_hirid (), label);
+    }
+
+  tree loop_begin_label
+    = ctx->get_backend ()->label (fnctx.fndecl, "", expr.get_locus ());
+  tree loop_begin_label_decl
+    = ctx->get_backend ()->label_definition_statement (loop_begin_label);
+  ctx->add_statement (loop_begin_label_decl);
+  ctx->push_loop_begin_label (loop_begin_label);
+
+  tree code_block
+    = CompileBlock::compile (expr.get_loop_block ().get (), ctx, nullptr);
+  tree loop_expr
+    = ctx->get_backend ()->loop_expression (code_block, expr.get_locus ());
+  ctx->add_statement (loop_expr);
+
+  ctx->pop_loop_context ();
+  translated = ctx->get_backend ()->var_expression (tmp, expr.get_locus ());
+
+  ctx->pop_loop_begin_label ();
+}
+
+void
+CompileExpr::visit (HIR::WhileLoopExpr &expr)
+{
+  fncontext fnctx = ctx->peek_fn ();
+  if (expr.has_loop_label ())
+    {
+      HIR::LoopLabel &loop_label = expr.get_loop_label ();
+      tree label
+	= ctx->get_backend ()->label (fnctx.fndecl,
+				      loop_label.get_lifetime ().get_name (),
+				      loop_label.get_locus ());
+      tree label_decl = ctx->get_backend ()->label_definition_statement (label);
+      ctx->add_statement (label_decl);
+      ctx->insert_label_decl (
+	loop_label.get_lifetime ().get_mappings ().get_hirid (), label);
+    }
+
+  std::vector<Bvariable *> locals;
+  Location start_location = expr.get_loop_block ()->get_locus ();
+  Location end_location = expr.get_loop_block ()->get_locus (); // FIXME
+
+  tree enclosing_scope = ctx->peek_enclosing_scope ();
+  tree loop_block
+    = ctx->get_backend ()->block (fnctx.fndecl, enclosing_scope, locals,
+				  start_location, end_location);
+  ctx->push_block (loop_block);
+
+  tree loop_begin_label
+    = ctx->get_backend ()->label (fnctx.fndecl, "", expr.get_locus ());
+  tree loop_begin_label_decl
+    = ctx->get_backend ()->label_definition_statement (loop_begin_label);
+  ctx->add_statement (loop_begin_label_decl);
+  ctx->push_loop_begin_label (loop_begin_label);
+
+  tree condition
+    = CompileExpr::Compile (expr.get_predicate_expr ().get (), ctx);
+  tree exit_expr
+    = ctx->get_backend ()->exit_expression (condition, expr.get_locus ());
+  ctx->add_statement (exit_expr);
+
+  tree code_block_stmt
+    = CompileBlock::compile (expr.get_loop_block ().get (), ctx, nullptr);
+  rust_assert (TREE_CODE (code_block_stmt) == BIND_EXPR);
+  ctx->add_statement (code_block_stmt);
+
+  ctx->pop_loop_begin_label ();
+  ctx->pop_block ();
+
+  tree loop_expr
+    = ctx->get_backend ()->loop_expression (loop_block, expr.get_locus ());
+  ctx->add_statement (loop_expr);
+}
+
+void
+CompileExpr::visit (HIR::BreakExpr &expr)
+{
+  if (expr.has_break_expr ())
+    {
+      tree compiled_expr = CompileExpr::Compile (expr.get_expr ().get (), ctx);
+
+      Bvariable *loop_result_holder = ctx->peek_loop_context ();
+      tree result_reference
+	= ctx->get_backend ()->var_expression (loop_result_holder,
+					       expr.get_expr ()->get_locus ());
+
+      tree assignment
+	= ctx->get_backend ()->assignment_statement (result_reference,
+						     compiled_expr,
+						     expr.get_locus ());
+      ctx->add_statement (assignment);
+    }
+
+  if (expr.has_label ())
+    {
+      NodeId resolved_node_id = UNKNOWN_NODEID;
+      if (!ctx->get_resolver ()->lookup_resolved_label (
+	    expr.get_label ().get_mappings ().get_nodeid (), &resolved_node_id))
+	{
+	  rust_error_at (
+	    expr.get_label ().get_locus (),
+	    "failed to resolve compiled label for label %s",
+	    expr.get_label ().get_mappings ().as_string ().c_str ());
+	  return;
+	}
+
+      HirId ref = UNKNOWN_HIRID;
+      if (!ctx->get_mappings ()->lookup_node_to_hir (resolved_node_id, &ref))
+	{
+	  rust_fatal_error (expr.get_locus (), "reverse lookup label failure");
+	  return;
+	}
+
+      tree label = NULL_TREE;
+      if (!ctx->lookup_label_decl (ref, &label))
+	{
+	  rust_error_at (expr.get_label ().get_locus (),
+			 "failed to lookup compiled label");
+	  return;
+	}
+
+      tree goto_label
+	= ctx->get_backend ()->goto_statement (label, expr.get_locus ());
+      ctx->add_statement (goto_label);
+    }
+  else
+    {
+      tree exit_expr = ctx->get_backend ()->exit_expression (
+	ctx->get_backend ()->boolean_constant_expression (true),
+	expr.get_locus ());
+      ctx->add_statement (exit_expr);
+    }
+}
+
+void
+CompileExpr::visit (HIR::ContinueExpr &expr)
+{
+  tree label = ctx->peek_loop_begin_label ();
+  if (expr.has_label ())
+    {
+      NodeId resolved_node_id = UNKNOWN_NODEID;
+      if (!ctx->get_resolver ()->lookup_resolved_label (
+	    expr.get_label ().get_mappings ().get_nodeid (), &resolved_node_id))
+	{
+	  rust_error_at (
+	    expr.get_label ().get_locus (),
+	    "failed to resolve compiled label for label %s",
+	    expr.get_label ().get_mappings ().as_string ().c_str ());
+	  return;
+	}
+
+      HirId ref = UNKNOWN_HIRID;
+      if (!ctx->get_mappings ()->lookup_node_to_hir (resolved_node_id, &ref))
+	{
+	  rust_fatal_error (expr.get_locus (), "reverse lookup label failure");
+	  return;
+	}
+
+      if (!ctx->lookup_label_decl (ref, &label))
+	{
+	  rust_error_at (expr.get_label ().get_locus (),
+			 "failed to lookup compiled label");
+	  return;
+	}
+    }
+
+  translated = ctx->get_backend ()->goto_statement (label, expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::BorrowExpr &expr)
+{
+  tree main_expr = CompileExpr::Compile (expr.get_expr ().get (), ctx);
+  if (SLICE_TYPE_P (TREE_TYPE (main_expr)))
+    {
+      translated = main_expr;
+      return;
+    }
+
+  TyTy::BaseType *tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (),
+				       &tyty))
+    return;
+
+  translated = address_expression (main_expr, expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::DereferenceExpr &expr)
+{
+  TyTy::BaseType *tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (),
+				       &tyty))
+    {
+      rust_fatal_error (expr.get_locus (),
+			"did not resolve type for this TupleExpr");
+      return;
+    }
+
+  tree main_expr = CompileExpr::Compile (expr.get_expr ().get (), ctx);
+
+  // this might be an operator overload situation lets check
+  TyTy::FnType *fntype;
+  bool is_op_overload = ctx->get_tyctx ()->lookup_operator_overload (
+    expr.get_mappings ().get_hirid (), &fntype);
+  if (is_op_overload)
+    {
+      auto lang_item_type = Analysis::RustLangItem::ItemType::DEREF;
+      tree operator_overload_call
+	= resolve_operator_overload (lang_item_type, expr, main_expr, nullptr,
+				     expr.get_expr ().get (), nullptr);
+
+      // rust deref always returns a reference from this overload then we can
+      // actually do the indirection
+      main_expr = operator_overload_call;
+    }
+
+  tree expected_type = TyTyResolveCompile::compile (ctx, tyty);
+  if (SLICE_TYPE_P (TREE_TYPE (main_expr)) && SLICE_TYPE_P (expected_type))
+    {
+      translated = main_expr;
+      return;
+    }
+
+  translated = indirect_expression (main_expr, expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::LiteralExpr &expr)
+{
+  TyTy::BaseType *tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (),
+				       &tyty))
+    return;
+
+  switch (expr.get_lit_type ())
+    {
+    case HIR::Literal::BOOL:
+      translated = compile_bool_literal (expr, tyty);
+      return;
+
+    case HIR::Literal::INT:
+      translated = compile_integer_literal (expr, tyty);
+      return;
+
+    case HIR::Literal::FLOAT:
+      translated = compile_float_literal (expr, tyty);
+      return;
+
+    case HIR::Literal::CHAR:
+      translated = compile_char_literal (expr, tyty);
+      return;
+
+    case HIR::Literal::BYTE:
+      translated = compile_byte_literal (expr, tyty);
+      return;
+
+    case HIR::Literal::STRING:
+      translated = compile_string_literal (expr, tyty);
+      return;
+
+    case HIR::Literal::BYTE_STRING:
+      translated = compile_byte_string_literal (expr, tyty);
+      return;
+    }
+}
+
+void
+CompileExpr::visit (HIR::AssignmentExpr &expr)
+{
+  auto lvalue = CompileExpr::Compile (expr.get_lhs (), ctx);
+  auto rvalue = CompileExpr::Compile (expr.get_rhs (), ctx);
+
+  // assignments are coercion sites so lets convert the rvalue if necessary
+  TyTy::BaseType *expected = nullptr;
+  TyTy::BaseType *actual = nullptr;
+
+  bool ok;
+  ok = ctx->get_tyctx ()->lookup_type (
+    expr.get_lhs ()->get_mappings ().get_hirid (), &expected);
+  rust_assert (ok);
+
+  ok = ctx->get_tyctx ()->lookup_type (
+    expr.get_rhs ()->get_mappings ().get_hirid (), &actual);
+  rust_assert (ok);
+
+  rvalue = coercion_site (expr.get_mappings ().get_hirid (), rvalue, actual,
+			  expected, expr.get_lhs ()->get_locus (),
+			  expr.get_rhs ()->get_locus ());
+
+  tree assignment
+    = ctx->get_backend ()->assignment_statement (lvalue, rvalue,
+						 expr.get_locus ());
+
+  ctx->add_statement (assignment);
+}
+
+// Helper for sort_tuple_patterns.
+// Determine whether Patterns a and b are really the same pattern.
+// FIXME: This is a nasty hack to avoid properly implementing a comparison
+//        for Patterns, which we really probably do want at some point.
+static bool
+patterns_mergeable (HIR::Pattern *a, HIR::Pattern *b)
+{
+  if (!a || !b)
+    return false;
+
+  HIR::Pattern::PatternType pat_type = a->get_pattern_type ();
+  if (b->get_pattern_type () != pat_type)
+    return false;
+
+  switch (pat_type)
+    {
+      case HIR::Pattern::PatternType::PATH: {
+	// FIXME: this is far too naive
+	HIR::PathPattern &aref = *static_cast<HIR::PathPattern *> (a);
+	HIR::PathPattern &bref = *static_cast<HIR::PathPattern *> (b);
+	if (aref.get_num_segments () != bref.get_num_segments ())
+	  return false;
+
+	const auto &asegs = aref.get_segments ();
+	const auto &bsegs = bref.get_segments ();
+	for (size_t i = 0; i < asegs.size (); i++)
+	  {
+	    if (asegs[i].as_string () != bsegs[i].as_string ())
+	      return false;
+	  }
+	return true;
+      }
+      break;
+      case HIR::Pattern::PatternType::LITERAL: {
+	HIR::LiteralPattern &aref = *static_cast<HIR::LiteralPattern *> (a);
+	HIR::LiteralPattern &bref = *static_cast<HIR::LiteralPattern *> (b);
+	return aref.get_literal ().is_equal (bref.get_literal ());
+      }
+      break;
+      case HIR::Pattern::PatternType::IDENTIFIER: {
+	// TODO
+      }
+      break;
+    case HIR::Pattern::PatternType::WILDCARD:
+      return true;
+      break;
+
+      // TODO
+
+    default:;
+    }
+  return false;
+}
+
+// A little container for rearranging the patterns and cases in a match
+// expression while simplifying.
+struct PatternMerge
+{
+  std::unique_ptr<HIR::MatchCase> wildcard;
+  std::vector<std::unique_ptr<HIR::Pattern>> heads;
+  std::vector<std::vector<HIR::MatchCase>> cases;
+};
+
+// Helper for simplify_tuple_match.
+// For each tuple pattern in a given match, pull out the first elt of the
+// tuple and construct a new MatchCase with the remaining tuple elts as the
+// pattern. Return a mapping from each _unique_ first tuple element to a
+// vec of cases for a new match.
+//
+// FIXME: This used to be a std::map<Pattern, Vec<MatchCase>>, but it doesn't
+// actually work like we want - the Pattern includes an HIR ID, which is unique
+// per Pattern object. This means we don't have a good means for comparing
+// Patterns. It would probably be best to actually implement a means of
+// properly comparing patterns, and then use an actual map.
+//
+static struct PatternMerge
+sort_tuple_patterns (HIR::MatchExpr &expr)
+{
+  rust_assert (expr.get_scrutinee_expr ()->get_expression_type ()
+	       == HIR::Expr::ExprType::Tuple);
+
+  struct PatternMerge result;
+  result.wildcard = nullptr;
+  result.heads = std::vector<std::unique_ptr<HIR::Pattern>> ();
+  result.cases = std::vector<std::vector<HIR::MatchCase>> ();
+
+  for (auto &match_case : expr.get_match_cases ())
+    {
+      HIR::MatchArm &case_arm = match_case.get_arm ();
+
+      // FIXME: Note we are only dealing with the first pattern in the arm.
+      // The patterns vector in the arm might hold many patterns, which are the
+      // patterns separated by the '|' token. Rustc abstracts these as "Or"
+      // patterns, and part of its simplification process is to get rid of them.
+      // We should get rid of the ORs too, maybe here or earlier than here?
+      auto pat = case_arm.get_patterns ()[0]->clone_pattern ();
+
+      // Record wildcards so we can add them in inner matches.
+      if (pat->get_pattern_type () == HIR::Pattern::PatternType::WILDCARD)
+	{
+	  // The *whole* pattern is a wild card (_).
+	  result.wildcard
+	    = std::unique_ptr<HIR::MatchCase> (new HIR::MatchCase (match_case));
+	  continue;
+	}
+
+      rust_assert (pat->get_pattern_type ()
+		   == HIR::Pattern::PatternType::TUPLE);
+
+      auto ref = *static_cast<HIR::TuplePattern *> (pat.get ());
+
+      rust_assert (ref.has_tuple_pattern_items ());
+
+      auto items
+	= HIR::TuplePattern (ref).get_items ()->clone_tuple_pattern_items ();
+      if (items->get_pattern_type ()
+	  == HIR::TuplePatternItems::TuplePatternItemType::MULTIPLE)
+	{
+	  auto items_ref
+	    = *static_cast<HIR::TuplePatternItemsMultiple *> (items.get ());
+
+	  // Pop the first pattern out
+	  auto patterns = std::vector<std::unique_ptr<HIR::Pattern>> ();
+	  auto first = items_ref.get_patterns ()[0]->clone_pattern ();
+	  for (auto p = items_ref.get_patterns ().begin () + 1;
+	       p != items_ref.get_patterns ().end (); p++)
+	    {
+	      patterns.push_back ((*p)->clone_pattern ());
+	    }
+
+	  // if there is only one pattern left, don't make a tuple out of it
+	  std::unique_ptr<HIR::Pattern> result_pattern;
+	  if (patterns.size () == 1)
+	    {
+	      result_pattern = std::move (patterns[0]);
+	    }
+	  else
+	    {
+	      auto new_items = std::unique_ptr<HIR::TuplePatternItems> (
+		new HIR::TuplePatternItemsMultiple (std::move (patterns)));
+
+	      // Construct a TuplePattern from the rest of the patterns
+	      result_pattern = std::unique_ptr<HIR::Pattern> (
+		new HIR::TuplePattern (ref.get_pattern_mappings (),
+				       std::move (new_items),
+				       ref.get_locus ()));
+	    }
+
+	  // I don't know why we need to make foo separately here but
+	  // using the { new_tuple } syntax in new_arm constructor does not
+	  // compile.
+	  auto foo = std::vector<std::unique_ptr<HIR::Pattern>> ();
+	  foo.emplace_back (std::move (result_pattern));
+	  HIR::MatchArm new_arm (std::move (foo), Location (), nullptr,
+				 AST::AttrVec ());
+
+	  HIR::MatchCase new_case (match_case.get_mappings (), new_arm,
+				   match_case.get_expr ()->clone_expr ());
+
+	  bool pushed = false;
+	  for (size_t i = 0; i < result.heads.size (); i++)
+	    {
+	      if (patterns_mergeable (result.heads[i].get (), first.get ()))
+		{
+		  result.cases[i].push_back (new_case);
+		  pushed = true;
+		}
+	    }
+
+	  if (!pushed)
+	    {
+	      result.heads.push_back (std::move (first));
+	      result.cases.push_back ({new_case});
+	    }
+	}
+      else /* TuplePatternItemType::RANGED */
+	{
+	  // FIXME
+	  gcc_unreachable ();
+	}
+    }
+
+  return result;
+}
+
+// Helper for CompileExpr::visit (HIR::MatchExpr).
+// Given a MatchExpr where the scrutinee is some kind of tuple, build an
+// equivalent match where only one element of the tuple is examined at a time.
+// This resulting match can then be lowered to a SWITCH_EXPR tree directly.
+//
+// The approach is as follows:
+// 1. Split the scrutinee and each pattern into the first (head) and the
+//    rest (tail).
+// 2. Build a mapping of unique pattern heads to the cases (tail and expr)
+//    that shared that pattern head in the original match.
+//    (This is the job of sort_tuple_patterns ()).
+// 3. For each unique pattern head, build a new MatchCase where the pattern
+//    is the unique head, and the expression is a new match where:
+//    - The scrutinee is the tail of the original scrutinee
+//    - The cases are are those built by the mapping in step 2, i.e. the
+//      tails of the patterns and the corresponing expressions from the
+//      original match expression.
+// 4. Do this recursively for each inner match, until there is nothing more
+//    to simplify.
+// 5. Build the resulting match which scrutinizes the head of the original
+//    scrutinee, using the cases built in step 3.
+static HIR::MatchExpr
+simplify_tuple_match (HIR::MatchExpr &expr)
+{
+  if (expr.get_scrutinee_expr ()->get_expression_type ()
+      != HIR::Expr::ExprType::Tuple)
+    return expr;
+
+  auto ref = *static_cast<HIR::TupleExpr *> (expr.get_scrutinee_expr ().get ());
+
+  auto &tail = ref.get_tuple_elems ();
+  rust_assert (tail.size () > 1);
+
+  auto head = std::move (tail[0]);
+  tail.erase (tail.begin (), tail.begin () + 1);
+
+  // e.g.
+  // match (tupA, tupB, tupC) {
+  //   (a1, b1, c1) => { blk1 },
+  //   (a2, b2, c2) => { blk2 },
+  //   (a1, b3, c3) => { blk3 },
+  // }
+  // tail = (tupB, tupC)
+  // head = tupA
+
+  // Make sure the tail is only a tuple if it consists of at least 2 elements.
+  std::unique_ptr<HIR::Expr> remaining;
+  if (tail.size () == 1)
+    remaining = std::move (tail[0]);
+  else
+    remaining = std::unique_ptr<HIR::Expr> (
+      new HIR::TupleExpr (ref.get_mappings (), std::move (tail),
+			  AST::AttrVec (), ref.get_outer_attrs (),
+			  ref.get_locus ()));
+
+  // e.g.
+  // a1 -> [(b1, c1) => { blk1 },
+  //        (b3, c3) => { blk3 }]
+  // a2 -> [(b2, c2) => { blk2 }]
+  struct PatternMerge map = sort_tuple_patterns (expr);
+
+  std::vector<HIR::MatchCase> cases;
+  // Construct the inner match for each unique first elt of the tuple
+  // patterns
+  for (size_t i = 0; i < map.heads.size (); i++)
+    {
+      auto inner_match_cases = map.cases[i];
+
+      // If there is a wildcard at the outer match level, then need to
+      // propegate the wildcard case into *every* inner match.
+      // FIXME: It is probably not correct to add this unconditionally, what if
+      // we have a pattern like (a, _, c)? Then there is already a wildcard in
+      // the inner matches, and having two will cause two 'default:' blocks
+      // which is an error.
+      if (map.wildcard != nullptr)
+	{
+	  inner_match_cases.push_back (*(map.wildcard.get ()));
+	}
+
+      // match (tupB, tupC) {
+      //   (b1, c1) => { blk1 },
+      //   (b3, c3) => { blk3 }
+      // }
+      HIR::MatchExpr inner_match (expr.get_mappings (),
+				  remaining->clone_expr (), inner_match_cases,
+				  AST::AttrVec (), expr.get_outer_attrs (),
+				  expr.get_locus ());
+
+      inner_match = simplify_tuple_match (inner_match);
+
+      auto outer_arm_pat = std::vector<std::unique_ptr<HIR::Pattern>> ();
+      outer_arm_pat.emplace_back (map.heads[i]->clone_pattern ());
+
+      HIR::MatchArm outer_arm (std::move (outer_arm_pat), expr.get_locus ());
+
+      // Need to move the inner match to the heap and put it in a unique_ptr to
+      // build the actual match case of the outer expression
+      // auto inner_expr = std::unique_ptr<HIR::Expr> (new HIR::MatchExpr
+      // (inner_match));
+      auto inner_expr = inner_match.clone_expr ();
+
+      // a1 => match (tupB, tupC) { ... }
+      HIR::MatchCase outer_case (expr.get_mappings (), outer_arm,
+				 std::move (inner_expr));
+
+      cases.push_back (outer_case);
+    }
+
+  // If there was a wildcard, make sure to include it at the outer match level
+  // too.
+  if (map.wildcard != nullptr)
+    {
+      cases.push_back (*(map.wildcard.get ()));
+    }
+
+  // match tupA {
+  //   a1 => match (tupB, tupC) {
+  //     (b1, c1) => { blk1 },
+  //     (b3, c3) => { blk3 }
+  //   }
+  //   a2 => match (tupB, tupC) {
+  //     (b2, c2) => { blk2 }
+  //   }
+  // }
+  HIR::MatchExpr outer_match (expr.get_mappings (), std::move (head), cases,
+			      AST::AttrVec (), expr.get_outer_attrs (),
+			      expr.get_locus ());
+
+  return outer_match;
+}
+
+// Helper for CompileExpr::visit (HIR::MatchExpr).
+// Check that the scrutinee of EXPR is a valid kind of expression to match on.
+// Return the TypeKind of the scrutinee if it is valid, or TyTy::TypeKind::ERROR
+// if not.
+static TyTy::TypeKind
+check_match_scrutinee (HIR::MatchExpr &expr, Context *ctx)
+{
+  TyTy::BaseType *scrutinee_expr_tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (
+	expr.get_scrutinee_expr ()->get_mappings ().get_hirid (),
+	&scrutinee_expr_tyty))
+    {
+      return TyTy::TypeKind::ERROR;
+    }
+
+  TyTy::TypeKind scrutinee_kind = scrutinee_expr_tyty->get_kind ();
+  rust_assert ((TyTy::is_primitive_type_kind (scrutinee_kind)
+		&& scrutinee_kind != TyTy::TypeKind::NEVER)
+	       || scrutinee_kind == TyTy::TypeKind::ADT
+	       || scrutinee_kind == TyTy::TypeKind::TUPLE);
+
+  if (scrutinee_kind == TyTy::TypeKind::ADT)
+    {
+      // this will need to change but for now the first pass implementation,
+      // lets assert this is the case
+      TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (scrutinee_expr_tyty);
+      rust_assert (adt->is_enum ());
+      rust_assert (adt->number_of_variants () > 0);
+    }
+  else if (scrutinee_kind == TyTy::TypeKind::FLOAT)
+    {
+      // FIXME: CASE_LABEL_EXPR does not support floating point types.
+      // Find another way to compile these.
+      rust_sorry_at (expr.get_locus (),
+		     "match on floating-point types is not yet supported");
+    }
+
+  TyTy::BaseType *expr_tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (),
+				       &expr_tyty))
+    {
+      return TyTy::TypeKind::ERROR;
+    }
+
+  return scrutinee_kind;
+}
+
+void
+CompileExpr::visit (HIR::MatchExpr &expr)
+{
+  // https://gcc.gnu.org/onlinedocs/gccint/Basic-Statements.html#Basic-Statements
+  // TODO
+  // SWITCH_ALL_CASES_P is true if the switch includes a default label or the
+  // case label ranges cover all possible values of the condition expression
+
+  /* Switch expression.
+
+     TREE_TYPE is the original type of the condition, before any
+     language required type conversions.  It may be NULL, in which case
+     the original type and final types are assumed to be the same.
+
+     Operand 0 is the expression used to perform the branch,
+     Operand 1 is the body of the switch, which probably contains
+       CASE_LABEL_EXPRs.  It may also be NULL, in which case operand 2
+       must not be NULL.  */
+  // DEFTREECODE (SWITCH_EXPR, "switch_expr", tcc_statement, 2)
+
+  /* Used to represent a case label.
+
+     Operand 0 is CASE_LOW.  It may be NULL_TREE, in which case the label
+       is a 'default' label.
+     Operand 1 is CASE_HIGH.  If it is NULL_TREE, the label is a simple
+       (one-value) case label.  If it is non-NULL_TREE, the case is a range.
+     Operand 2 is CASE_LABEL, which has the corresponding LABEL_DECL.
+     Operand 3 is CASE_CHAIN.  This operand is only used in tree-cfg.cc to
+       speed up the lookup of case labels which use a particular edge in
+       the control flow graph.  */
+  // DEFTREECODE (CASE_LABEL_EXPR, "case_label_expr", tcc_statement, 4)
+
+  TyTy::TypeKind scrutinee_kind = check_match_scrutinee (expr, ctx);
+  if (scrutinee_kind == TyTy::TypeKind::ERROR)
+    {
+      translated = error_mark_node;
+      return;
+    }
+
+  TyTy::BaseType *expr_tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (),
+				       &expr_tyty))
+    {
+      translated = error_mark_node;
+      return;
+    }
+
+  fncontext fnctx = ctx->peek_fn ();
+  Bvariable *tmp = NULL;
+  bool needs_temp = !expr_tyty->is_unit ();
+  if (needs_temp)
+    {
+      tree enclosing_scope = ctx->peek_enclosing_scope ();
+      tree block_type = TyTyResolveCompile::compile (ctx, expr_tyty);
+
+      bool is_address_taken = false;
+      tree ret_var_stmt = nullptr;
+      tmp = ctx->get_backend ()->temporary_variable (
+	fnctx.fndecl, enclosing_scope, block_type, NULL, is_address_taken,
+	expr.get_locus (), &ret_var_stmt);
+      ctx->add_statement (ret_var_stmt);
+    }
+
+  // lets compile the scrutinee expression
+  tree match_scrutinee_expr
+    = CompileExpr::Compile (expr.get_scrutinee_expr ().get (), ctx);
+
+  tree match_scrutinee_expr_qualifier_expr;
+  if (TyTy::is_primitive_type_kind (scrutinee_kind))
+    {
+      match_scrutinee_expr_qualifier_expr = match_scrutinee_expr;
+    }
+  else if (scrutinee_kind == TyTy::TypeKind::ADT)
+    {
+      // need to access qualifier the field, if we use QUAL_UNION_TYPE this
+      // would be DECL_QUALIFIER i think. For now this will just access the
+      // first record field and its respective qualifier because it will always
+      // be set because this is all a big special union
+      tree scrutinee_first_record_expr
+	= ctx->get_backend ()->struct_field_expression (
+	  match_scrutinee_expr, 0, expr.get_scrutinee_expr ()->get_locus ());
+      match_scrutinee_expr_qualifier_expr
+	= ctx->get_backend ()->struct_field_expression (
+	  scrutinee_first_record_expr, 0,
+	  expr.get_scrutinee_expr ()->get_locus ());
+    }
+  else if (scrutinee_kind == TyTy::TypeKind::TUPLE)
+    {
+      // match on tuple becomes a series of nested switches, with one level
+      // for each element of the tuple from left to right.
+      auto exprtype = expr.get_scrutinee_expr ()->get_expression_type ();
+      switch (exprtype)
+	{
+	  case HIR::Expr::ExprType::Tuple: {
+	    // Build an equivalent expression which is nicer to lower.
+	    HIR::MatchExpr outer_match = simplify_tuple_match (expr);
+
+	    // We've rearranged the match into something that lowers better
+	    // to GENERIC trees.
+	    // For actually doing the lowering we need to compile the match
+	    // we've just made. But we're half-way through compiling the
+	    // original one.
+	    // ...
+	    // For now, let's just replace the original with the rearranged one
+	    // we just made, and compile that instead. What could go wrong? :)
+	    //
+	    // FIXME: What about when we decide a temporary is needed above?
+	    //        We might have already pushed a statement for it that
+	    //        we no longer need. Probably need to rearrange the order
+	    //        of these steps.
+	    expr = outer_match;
+
+	    scrutinee_kind = check_match_scrutinee (expr, ctx);
+	    if (scrutinee_kind == TyTy::TypeKind::ERROR)
+	      {
+		translated = error_mark_node;
+		return;
+	      }
+
+	    // Now compile the scrutinee of the simplified match.
+	    // FIXME: this part is duplicated from above.
+	    match_scrutinee_expr
+	      = CompileExpr::Compile (expr.get_scrutinee_expr ().get (), ctx);
+
+	    if (TyTy::is_primitive_type_kind (scrutinee_kind))
+	      {
+		match_scrutinee_expr_qualifier_expr = match_scrutinee_expr;
+	      }
+	    else if (scrutinee_kind == TyTy::TypeKind::ADT)
+	      {
+		// need to access qualifier the field, if we use QUAL_UNION_TYPE
+		// this would be DECL_QUALIFIER i think. For now this will just
+		// access the first record field and its respective qualifier
+		// because it will always be set because this is all a big
+		// special union
+		tree scrutinee_first_record_expr
+		  = ctx->get_backend ()->struct_field_expression (
+		    match_scrutinee_expr, 0,
+		    expr.get_scrutinee_expr ()->get_locus ());
+		match_scrutinee_expr_qualifier_expr
+		  = ctx->get_backend ()->struct_field_expression (
+		    scrutinee_first_record_expr, 0,
+		    expr.get_scrutinee_expr ()->get_locus ());
+	      }
+	    else
+	      {
+		// FIXME: There are other cases, but it better not be a Tuple
+		gcc_unreachable ();
+	      }
+	  }
+	  break;
+
+	  case HIR::Expr::ExprType::Path: {
+	    // FIXME
+	    gcc_unreachable ();
+	  }
+	  break;
+
+	default:
+	  gcc_unreachable ();
+	}
+    }
+  else
+    {
+      // FIXME: match on other types of expressions not yet implemented.
+      gcc_unreachable ();
+    }
+
+  // setup the end label so the cases can exit properly
+  tree fndecl = fnctx.fndecl;
+  Location end_label_locus = expr.get_locus (); // FIXME
+  tree end_label
+    = ctx->get_backend ()->label (fndecl,
+				  "" /* empty creates an artificial label */,
+				  end_label_locus);
+  tree end_label_decl_statement
+    = ctx->get_backend ()->label_definition_statement (end_label);
+
+  // setup the switch-body-block
+  Location start_location; // FIXME
+  Location end_location;   // FIXME
+  tree enclosing_scope = ctx->peek_enclosing_scope ();
+  tree switch_body_block
+    = ctx->get_backend ()->block (fndecl, enclosing_scope, {}, start_location,
+				  end_location);
+  ctx->push_block (switch_body_block);
+
+  for (auto &kase : expr.get_match_cases ())
+    {
+      // for now lets just get single pattern's working
+      HIR::MatchArm &kase_arm = kase.get_arm ();
+      rust_assert (kase_arm.get_patterns ().size () > 0);
+
+      // generate implicit label
+      Location arm_locus = kase_arm.get_locus ();
+      tree case_label = ctx->get_backend ()->label (
+	fndecl, "" /* empty creates an artificial label */, arm_locus);
+
+      // setup the bindings for the block
+      for (auto &kase_pattern : kase_arm.get_patterns ())
+	{
+	  tree switch_kase_expr
+	    = CompilePatternCaseLabelExpr::Compile (kase_pattern.get (),
+						    case_label, ctx);
+	  ctx->add_statement (switch_kase_expr);
+
+	  CompilePatternBindings::Compile (kase_pattern.get (),
+					   match_scrutinee_expr, ctx);
+	}
+
+      // compile the expr and setup the assignment if required when tmp != NULL
+      tree kase_expr_tree = CompileExpr::Compile (kase.get_expr ().get (), ctx);
+      if (tmp != NULL)
+	{
+	  tree result_reference
+	    = ctx->get_backend ()->var_expression (tmp, arm_locus);
+	  tree assignment
+	    = ctx->get_backend ()->assignment_statement (result_reference,
+							 kase_expr_tree,
+							 arm_locus);
+	  ctx->add_statement (assignment);
+	}
+
+      // go to end label
+      tree goto_end_label = build1_loc (arm_locus.gcc_location (), GOTO_EXPR,
+					void_type_node, end_label);
+      ctx->add_statement (goto_end_label);
+    }
+
+  // setup the switch expression
+  tree match_body = ctx->pop_block ();
+  tree match_expr_stmt
+    = build2_loc (expr.get_locus ().gcc_location (), SWITCH_EXPR,
+		  TREE_TYPE (match_scrutinee_expr_qualifier_expr),
+		  match_scrutinee_expr_qualifier_expr, match_body);
+  ctx->add_statement (match_expr_stmt);
+  ctx->add_statement (end_label_decl_statement);
+
+  if (tmp != NULL)
+    {
+      translated = ctx->get_backend ()->var_expression (tmp, expr.get_locus ());
+    }
+}
+
+void
+CompileExpr::visit (HIR::CallExpr &expr)
+{
+  TyTy::BaseType *tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (
+	expr.get_fnexpr ()->get_mappings ().get_hirid (), &tyty))
+    {
+      rust_error_at (expr.get_locus (), "unknown type");
+      return;
+    }
+
+  // must be a tuple constructor
+  bool is_fn = tyty->get_kind () == TyTy::TypeKind::FNDEF
+	       || tyty->get_kind () == TyTy::TypeKind::FNPTR;
+  bool is_adt_ctor = !is_fn;
+  if (is_adt_ctor)
+    {
+      rust_assert (tyty->get_kind () == TyTy::TypeKind::ADT);
+      TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (tyty);
+      tree compiled_adt_type = TyTyResolveCompile::compile (ctx, tyty);
+
+      // what variant is it?
+      int union_disriminator = -1;
+      TyTy::VariantDef *variant = nullptr;
+      if (!adt->is_enum ())
+	{
+	  rust_assert (adt->number_of_variants () == 1);
+	  variant = adt->get_variants ().at (0);
+	}
+      else
+	{
+	  HirId variant_id;
+	  bool ok = ctx->get_tyctx ()->lookup_variant_definition (
+	    expr.get_fnexpr ()->get_mappings ().get_hirid (), &variant_id);
+	  rust_assert (ok);
+
+	  ok = adt->lookup_variant_by_id (variant_id, &variant,
+					  &union_disriminator);
+	  rust_assert (ok);
+	}
+
+      // this assumes all fields are in order from type resolution and if a
+      // base struct was specified those fields are filed via accesors
+      std::vector<tree> arguments;
+      for (size_t i = 0; i < expr.get_arguments ().size (); i++)
+	{
+	  auto &argument = expr.get_arguments ().at (i);
+	  auto rvalue = CompileExpr::Compile (argument.get (), ctx);
+
+	  // assignments are coercion sites so lets convert the rvalue if
+	  // necessary
+	  auto respective_field = variant->get_field_at_index (i);
+	  auto expected = respective_field->get_field_type ();
+
+	  TyTy::BaseType *actual = nullptr;
+	  bool ok = ctx->get_tyctx ()->lookup_type (
+	    argument->get_mappings ().get_hirid (), &actual);
+	  rust_assert (ok);
+
+	  // coerce it if required
+	  Location lvalue_locus
+	    = ctx->get_mappings ()->lookup_location (expected->get_ty_ref ());
+	  Location rvalue_locus = argument->get_locus ();
+	  rvalue
+	    = coercion_site (argument->get_mappings ().get_hirid (), rvalue,
+			     actual, expected, lvalue_locus, rvalue_locus);
+
+	  // add it to the list
+	  arguments.push_back (rvalue);
+	}
+
+      // the constructor depends on whether this is actually an enum or not if
+      // its an enum we need to setup the discriminator
+      std::vector<tree> ctor_arguments;
+      if (adt->is_enum ())
+	{
+	  HIR::Expr *discrim_expr = variant->get_discriminant ();
+	  tree discrim_expr_node = CompileExpr::Compile (discrim_expr, ctx);
+	  tree folded_discrim_expr = fold_expr (discrim_expr_node);
+	  tree qualifier = folded_discrim_expr;
+
+	  ctor_arguments.push_back (qualifier);
+	}
+      for (auto &arg : arguments)
+	ctor_arguments.push_back (arg);
+
+      translated = ctx->get_backend ()->constructor_expression (
+	compiled_adt_type, adt->is_enum (), ctor_arguments, union_disriminator,
+	expr.get_locus ());
+
+      return;
+    }
+
+  auto get_parameter_tyty_at_index
+    = [] (const TyTy::BaseType *base, size_t index,
+	  TyTy::BaseType **result) -> bool {
+    bool is_fn = base->get_kind () == TyTy::TypeKind::FNDEF
+		 || base->get_kind () == TyTy::TypeKind::FNPTR;
+    rust_assert (is_fn);
+
+    if (base->get_kind () == TyTy::TypeKind::FNPTR)
+      {
+	const TyTy::FnPtr *fn = static_cast<const TyTy::FnPtr *> (base);
+	*result = fn->param_at (index);
+
+	return true;
+      }
+
+    const TyTy::FnType *fn = static_cast<const TyTy::FnType *> (base);
+    auto param = fn->param_at (index);
+    *result = param.second;
+
+    return true;
+  };
+
+  bool is_varadic = false;
+  if (tyty->get_kind () == TyTy::TypeKind::FNDEF)
+    {
+      const TyTy::FnType *fn = static_cast<const TyTy::FnType *> (tyty);
+      is_varadic = fn->is_varadic ();
+    }
+
+  size_t required_num_args;
+  if (tyty->get_kind () == TyTy::TypeKind::FNDEF)
+    {
+      const TyTy::FnType *fn = static_cast<const TyTy::FnType *> (tyty);
+      required_num_args = fn->num_params ();
+    }
+  else
+    {
+      const TyTy::FnPtr *fn = static_cast<const TyTy::FnPtr *> (tyty);
+      required_num_args = fn->num_params ();
+    }
+
+  std::vector<tree> args;
+  for (size_t i = 0; i < expr.get_arguments ().size (); i++)
+    {
+      auto &argument = expr.get_arguments ().at (i);
+      auto rvalue = CompileExpr::Compile (argument.get (), ctx);
+
+      if (is_varadic && i >= required_num_args)
+	{
+	  args.push_back (rvalue);
+	  continue;
+	}
+
+      // assignments are coercion sites so lets convert the rvalue if
+      // necessary
+      bool ok;
+      TyTy::BaseType *expected = nullptr;
+      ok = get_parameter_tyty_at_index (tyty, i, &expected);
+      rust_assert (ok);
+
+      TyTy::BaseType *actual = nullptr;
+      ok = ctx->get_tyctx ()->lookup_type (
+	argument->get_mappings ().get_hirid (), &actual);
+      rust_assert (ok);
+
+      // coerce it if required
+      Location lvalue_locus
+	= ctx->get_mappings ()->lookup_location (expected->get_ty_ref ());
+      Location rvalue_locus = argument->get_locus ();
+      rvalue = coercion_site (argument->get_mappings ().get_hirid (), rvalue,
+			      actual, expected, lvalue_locus, rvalue_locus);
+
+      // add it to the list
+      args.push_back (rvalue);
+    }
+
+  // must be a call to a function
+  auto fn_address = CompileExpr::Compile (expr.get_fnexpr (), ctx);
+  translated = ctx->get_backend ()->call_expression (fn_address, args, nullptr,
+						     expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::MethodCallExpr &expr)
+{
+  // method receiver
+  tree self = CompileExpr::Compile (expr.get_receiver ().get (), ctx);
+
+  // lookup the resolved name
+  NodeId resolved_node_id = UNKNOWN_NODEID;
+  if (!ctx->get_resolver ()->lookup_resolved_name (
+	expr.get_mappings ().get_nodeid (), &resolved_node_id))
+    {
+      rust_error_at (expr.get_locus (), "failed to lookup resolved MethodCall");
+      return;
+    }
+
+  // reverse lookup
+  HirId ref;
+  if (!ctx->get_mappings ()->lookup_node_to_hir (resolved_node_id, &ref))
+    {
+      rust_fatal_error (expr.get_locus (), "reverse lookup failure");
+      return;
+    }
+
+  // lookup the expected function type
+  TyTy::BaseType *lookup_fntype = nullptr;
+  bool ok = ctx->get_tyctx ()->lookup_type (
+    expr.get_method_name ().get_mappings ().get_hirid (), &lookup_fntype);
+  rust_assert (ok);
+  rust_assert (lookup_fntype->get_kind () == TyTy::TypeKind::FNDEF);
+  TyTy::FnType *fntype = static_cast<TyTy::FnType *> (lookup_fntype);
+
+  TyTy::BaseType *receiver = nullptr;
+  ok = ctx->get_tyctx ()->lookup_receiver (expr.get_mappings ().get_hirid (),
+					   &receiver);
+  rust_assert (ok);
+
+  bool is_dyn_dispatch
+    = receiver->get_root ()->get_kind () == TyTy::TypeKind::DYNAMIC;
+  bool is_generic_receiver = receiver->get_kind () == TyTy::TypeKind::PARAM;
+  if (is_generic_receiver)
+    {
+      TyTy::ParamType *p = static_cast<TyTy::ParamType *> (receiver);
+      receiver = p->resolve ();
+    }
+
+  tree fn_expr = error_mark_node;
+  if (is_dyn_dispatch)
+    {
+      const TyTy::DynamicObjectType *dyn
+	= static_cast<const TyTy::DynamicObjectType *> (receiver->get_root ());
+
+      std::vector<HIR::Expr *> arguments;
+      for (auto &arg : expr.get_arguments ())
+	arguments.push_back (arg.get ());
+
+      fn_expr
+	= get_fn_addr_from_dyn (dyn, receiver, fntype, self, expr.get_locus ());
+      self = get_receiver_from_dyn (dyn, receiver, fntype, self,
+				    expr.get_locus ());
+    }
+  else
+    {
+      // lookup compiled functions since it may have already been compiled
+      HIR::PathExprSegment method_name = expr.get_method_name ();
+      HIR::PathIdentSegment segment_name = method_name.get_segment ();
+      fn_expr
+	= resolve_method_address (fntype, ref, receiver, segment_name,
+				  expr.get_mappings (), expr.get_locus ());
+    }
+
+  // lookup the autoderef mappings
+  HirId autoderef_mappings_id
+    = expr.get_receiver ()->get_mappings ().get_hirid ();
+  std::vector<Resolver::Adjustment> *adjustments = nullptr;
+  ok = ctx->get_tyctx ()->lookup_autoderef_mappings (autoderef_mappings_id,
+						     &adjustments);
+  rust_assert (ok);
+
+  // apply adjustments for the fn call
+  self = resolve_adjustements (*adjustments, self,
+			       expr.get_receiver ()->get_locus ());
+
+  std::vector<tree> args;
+  args.push_back (self); // adjusted self
+
+  // normal args
+  for (size_t i = 0; i < expr.get_arguments ().size (); i++)
+    {
+      auto &argument = expr.get_arguments ().at (i);
+      auto rvalue = CompileExpr::Compile (argument.get (), ctx);
+
+      // assignments are coercion sites so lets convert the rvalue if
+      // necessary, offset from the already adjusted implicit self
+      bool ok;
+      TyTy::BaseType *expected = fntype->param_at (i + 1).second;
+
+      TyTy::BaseType *actual = nullptr;
+      ok = ctx->get_tyctx ()->lookup_type (
+	argument->get_mappings ().get_hirid (), &actual);
+      rust_assert (ok);
+
+      // coerce it if required
+      Location lvalue_locus
+	= ctx->get_mappings ()->lookup_location (expected->get_ty_ref ());
+      Location rvalue_locus = argument->get_locus ();
+      rvalue = coercion_site (argument->get_mappings ().get_hirid (), rvalue,
+			      actual, expected, lvalue_locus, rvalue_locus);
+
+      // add it to the list
+      args.push_back (rvalue);
+    }
+
+  translated = ctx->get_backend ()->call_expression (fn_expr, args, nullptr,
+						     expr.get_locus ());
+}
+
+tree
+CompileExpr::get_fn_addr_from_dyn (const TyTy::DynamicObjectType *dyn,
+				   TyTy::BaseType *receiver,
+				   TyTy::FnType *fntype, tree receiver_ref,
+				   Location expr_locus)
+{
+  size_t offs = 0;
+  const Resolver::TraitItemReference *ref = nullptr;
+  for (auto &bound : dyn->get_object_items ())
+    {
+      const Resolver::TraitItemReference *item = bound.first;
+      auto t = item->get_tyty ();
+      rust_assert (t->get_kind () == TyTy::TypeKind::FNDEF);
+      auto ft = static_cast<TyTy::FnType *> (t);
+
+      if (ft->get_id () == fntype->get_id ())
+	{
+	  ref = item;
+	  break;
+	}
+      offs++;
+    }
+
+  if (ref == nullptr)
+    return error_mark_node;
+
+  // get any indirection sorted out
+  if (receiver->get_kind () == TyTy::TypeKind::REF)
+    {
+      tree indirect = indirect_expression (receiver_ref, expr_locus);
+      receiver_ref = indirect;
+    }
+
+  // cast it to the correct fntype
+  tree expected_fntype = TyTyResolveCompile::compile (ctx, fntype, true);
+  tree idx = build_int_cst (size_type_node, offs);
+
+  tree vtable_ptr
+    = ctx->get_backend ()->struct_field_expression (receiver_ref, 1,
+						    expr_locus);
+  tree vtable_array_access = build4_loc (expr_locus.gcc_location (), ARRAY_REF,
+					 TREE_TYPE (TREE_TYPE (vtable_ptr)),
+					 vtable_ptr, idx, NULL_TREE, NULL_TREE);
+
+  tree vcall
+    = build3_loc (expr_locus.gcc_location (), OBJ_TYPE_REF, expected_fntype,
+		  vtable_array_access, receiver_ref, idx);
+
+  return vcall;
+}
+
+tree
+CompileExpr::get_receiver_from_dyn (const TyTy::DynamicObjectType *dyn,
+				    TyTy::BaseType *receiver,
+				    TyTy::FnType *fntype, tree receiver_ref,
+				    Location expr_locus)
+{
+  // get any indirection sorted out
+  if (receiver->get_kind () == TyTy::TypeKind::REF)
+    {
+      tree indirect = indirect_expression (receiver_ref, expr_locus);
+      receiver_ref = indirect;
+    }
+
+  // access the offs + 1 for the fnptr and offs=0 for the reciever obj
+  return ctx->get_backend ()->struct_field_expression (receiver_ref, 0,
+						       expr_locus);
+}
+
+tree
+CompileExpr::resolve_method_address (TyTy::FnType *fntype, HirId ref,
+				     TyTy::BaseType *receiver,
+				     HIR::PathIdentSegment &segment,
+				     Analysis::NodeMapping expr_mappings,
+				     Location expr_locus)
+{
+  // lookup compiled functions since it may have already been compiled
+  tree fn = NULL_TREE;
+  if (ctx->lookup_function_decl (fntype->get_ty_ref (), &fn))
+    {
+      return address_expression (fn, expr_locus);
+    }
+
+  // Now we can try and resolve the address since this might be a forward
+  // declared function, generic function which has not be compiled yet or
+  // its an not yet trait bound function
+  HIR::ImplItem *resolved_item
+    = ctx->get_mappings ()->lookup_hir_implitem (ref, nullptr);
+  if (resolved_item != nullptr)
+    {
+      if (!fntype->has_subsititions_defined ())
+	return CompileInherentImplItem::Compile (resolved_item, ctx);
+
+      return CompileInherentImplItem::Compile (resolved_item, ctx, fntype);
+    }
+
+  // it might be resolved to a trait item
+  HIR::TraitItem *trait_item
+    = ctx->get_mappings ()->lookup_hir_trait_item (ref);
+  HIR::Trait *trait = ctx->get_mappings ()->lookup_trait_item_mapping (
+    trait_item->get_mappings ().get_hirid ());
+
+  Resolver::TraitReference *trait_ref
+    = &Resolver::TraitReference::error_node ();
+  bool ok = ctx->get_tyctx ()->lookup_trait_reference (
+    trait->get_mappings ().get_defid (), &trait_ref);
+  rust_assert (ok);
+
+  // the type resolver can only resolve type bounds to their trait
+  // item so its up to us to figure out if this path should resolve
+  // to an trait-impl-block-item or if it can be defaulted to the
+  // trait-impl-item's definition
+
+  auto root = receiver->get_root ();
+  std::vector<Resolver::PathProbeCandidate> candidates
+    = Resolver::PathProbeType::Probe (root, segment, true /* probe_impls */,
+				      false /* probe_bounds */,
+				      true /* ignore_mandatory_trait_items */);
+  if (candidates.size () == 0)
+    {
+      // this means we are defaulting back to the trait_item if
+      // possible
+      Resolver::TraitItemReference *trait_item_ref = nullptr;
+      bool ok = trait_ref->lookup_hir_trait_item (*trait_item, &trait_item_ref);
+      rust_assert (ok);				    // found
+      rust_assert (trait_item_ref->is_optional ()); // has definition
+
+      // FIXME Optional means it has a definition and an associated
+      // block which can be a default implementation, if it does not
+      // contain an implementation we should actually return
+      // error_mark_node
+
+      return CompileTraitItem::Compile (trait_item_ref->get_hir_trait_item (),
+					ctx, fntype, true, expr_locus);
+    }
+  else
+    {
+      // FIXME this will be a case to return error_mark_node, there is
+      // an error scenario where a Trait Foo has a method Bar, but this
+      // receiver does not implement this trait or has an incompatible
+      // implementation and we should just return error_mark_node
+
+      rust_assert (candidates.size () == 1);
+      auto &candidate = candidates.at (0);
+      rust_assert (candidate.is_impl_candidate ());
+      rust_assert (candidate.ty->get_kind () == TyTy::TypeKind::FNDEF);
+      TyTy::FnType *candidate_call = static_cast<TyTy::FnType *> (candidate.ty);
+
+      HIR::ImplItem *impl_item = candidate.item.impl.impl_item;
+      if (!candidate_call->has_subsititions_defined ())
+	return CompileInherentImplItem::Compile (impl_item, ctx);
+
+      TyTy::BaseType *monomorphized = candidate_call;
+      if (candidate_call->needs_generic_substitutions ())
+	{
+	  TyTy::BaseType *infer_impl_call
+	    = candidate_call->infer_substitions (expr_locus);
+	  monomorphized = infer_impl_call->unify (fntype);
+	}
+
+      return CompileInherentImplItem::Compile (impl_item, ctx, monomorphized);
+    }
+}
+
+tree
+CompileExpr::resolve_operator_overload (
+  Analysis::RustLangItem::ItemType lang_item_type, HIR::OperatorExprMeta expr,
+  tree lhs, tree rhs, HIR::Expr *lhs_expr, HIR::Expr *rhs_expr)
+{
+  TyTy::FnType *fntype;
+  bool is_op_overload = ctx->get_tyctx ()->lookup_operator_overload (
+    expr.get_mappings ().get_hirid (), &fntype);
+  rust_assert (is_op_overload);
+
+  // lookup the resolved name
+  NodeId resolved_node_id = UNKNOWN_NODEID;
+  bool ok = ctx->get_resolver ()->lookup_resolved_name (
+    expr.get_mappings ().get_nodeid (), &resolved_node_id);
+  rust_assert (ok);
+
+  // reverse lookup
+  HirId ref;
+  ok = ctx->get_mappings ()->lookup_node_to_hir (resolved_node_id, &ref);
+  rust_assert (ok);
+
+  TyTy::BaseType *receiver = nullptr;
+  ok = ctx->get_tyctx ()->lookup_receiver (expr.get_mappings ().get_hirid (),
+					   &receiver);
+  rust_assert (ok);
+
+  bool is_generic_receiver = receiver->get_kind () == TyTy::TypeKind::PARAM;
+  if (is_generic_receiver)
+    {
+      TyTy::ParamType *p = static_cast<TyTy::ParamType *> (receiver);
+      receiver = p->resolve ();
+    }
+
+  // lookup compiled functions since it may have already been compiled
+  HIR::PathIdentSegment segment_name (
+    Analysis::RustLangItem::ToString (lang_item_type));
+  tree fn_expr
+    = resolve_method_address (fntype, ref, receiver, segment_name,
+			      expr.get_mappings (), expr.get_locus ());
+
+  // lookup the autoderef mappings
+  std::vector<Resolver::Adjustment> *adjustments = nullptr;
+  ok = ctx->get_tyctx ()->lookup_autoderef_mappings (
+    expr.get_lvalue_mappings ().get_hirid (), &adjustments);
+  rust_assert (ok);
+
+  // apply adjustments for the fn call
+  tree self = resolve_adjustements (*adjustments, lhs, lhs_expr->get_locus ());
+
+  std::vector<tree> args;
+  args.push_back (self); // adjusted self
+  if (rhs != nullptr)	 // can be null for negation_expr (unary ones)
+    args.push_back (rhs);
+
+  return ctx->get_backend ()->call_expression (fn_expr, args, nullptr,
+					       expr.get_locus ());
+}
+
+tree
+CompileExpr::compile_bool_literal (const HIR::LiteralExpr &expr,
+				   const TyTy::BaseType *tyty)
+{
+  rust_assert (expr.get_lit_type () == HIR::Literal::BOOL);
+
+  const auto literal_value = expr.get_literal ();
+  bool bval = literal_value.as_string ().compare ("true") == 0;
+  return ctx->get_backend ()->boolean_constant_expression (bval);
+}
+
+tree
+CompileExpr::compile_integer_literal (const HIR::LiteralExpr &expr,
+				      const TyTy::BaseType *tyty)
+{
+  rust_assert (expr.get_lit_type () == HIR::Literal::INT);
+  const auto literal_value = expr.get_literal ();
+
+  tree type = TyTyResolveCompile::compile (ctx, tyty);
+
+  mpz_t ival;
+  if (mpz_init_set_str (ival, literal_value.as_string ().c_str (), 10) != 0)
+    {
+      rust_error_at (expr.get_locus (), "bad number in literal");
+      return error_mark_node;
+    }
+
+  mpz_t type_min;
+  mpz_t type_max;
+  mpz_init (type_min);
+  mpz_init (type_max);
+  get_type_static_bounds (type, type_min, type_max);
+
+  if (mpz_cmp (ival, type_min) < 0 || mpz_cmp (ival, type_max) > 0)
+    {
+      rust_error_at (expr.get_locus (),
+		     "integer overflows the respective type %<%s%>",
+		     tyty->get_name ().c_str ());
+      return error_mark_node;
+    }
+
+  tree result = wide_int_to_tree (type, wi::from_mpz (type, ival, true));
+
+  mpz_clear (type_min);
+  mpz_clear (type_max);
+  mpz_clear (ival);
+
+  return result;
+}
+
+tree
+CompileExpr::compile_float_literal (const HIR::LiteralExpr &expr,
+				    const TyTy::BaseType *tyty)
+{
+  rust_assert (expr.get_lit_type () == HIR::Literal::FLOAT);
+  const auto literal_value = expr.get_literal ();
+
+  mpfr_t fval;
+  if (mpfr_init_set_str (fval, literal_value.as_string ().c_str (), 10,
+			 MPFR_RNDN)
+      != 0)
+    {
+      rust_error_at (expr.get_locus (), "bad number in literal");
+      return error_mark_node;
+    }
+
+  tree type = TyTyResolveCompile::compile (ctx, tyty);
+
+  // taken from:
+  // see go/gofrontend/expressions.cc:check_float_type
+  mpfr_exp_t exp = mpfr_get_exp (fval);
+  bool real_value_overflow = exp > TYPE_PRECISION (type);
+
+  REAL_VALUE_TYPE r1;
+  real_from_mpfr (&r1, fval, type, GMP_RNDN);
+  REAL_VALUE_TYPE r2;
+  real_convert (&r2, TYPE_MODE (type), &r1);
+
+  tree real_value = build_real (type, r2);
+  if (TREE_OVERFLOW (real_value) || real_value_overflow)
+    {
+      rust_error_at (expr.get_locus (),
+		     "decimal overflows the respective type %<%s%>",
+		     tyty->get_name ().c_str ());
+      return error_mark_node;
+    }
+
+  return real_value;
+}
+
+tree
+CompileExpr::compile_char_literal (const HIR::LiteralExpr &expr,
+				   const TyTy::BaseType *tyty)
+{
+  rust_assert (expr.get_lit_type () == HIR::Literal::CHAR);
+  const auto literal_value = expr.get_literal ();
+
+  // FIXME needs wchar_t
+  char c = literal_value.as_string ().c_str ()[0];
+  return ctx->get_backend ()->wchar_constant_expression (c);
+}
+
+tree
+CompileExpr::compile_byte_literal (const HIR::LiteralExpr &expr,
+				   const TyTy::BaseType *tyty)
+{
+  rust_assert (expr.get_lit_type () == HIR::Literal::BYTE);
+  const auto literal_value = expr.get_literal ();
+
+  tree type = TyTyResolveCompile::compile (ctx, tyty);
+  char c = literal_value.as_string ().c_str ()[0];
+  return build_int_cst (type, c);
+}
+
+tree
+CompileExpr::compile_string_literal (const HIR::LiteralExpr &expr,
+				     const TyTy::BaseType *tyty)
+{
+  tree fat_pointer = TyTyResolveCompile::compile (ctx, tyty);
+
+  rust_assert (expr.get_lit_type () == HIR::Literal::STRING);
+  const auto literal_value = expr.get_literal ();
+
+  auto base = ctx->get_backend ()->string_constant_expression (
+    literal_value.as_string ());
+  tree data = address_expression (base, expr.get_locus ());
+
+  TyTy::BaseType *usize = nullptr;
+  bool ok = ctx->get_tyctx ()->lookup_builtin ("usize", &usize);
+  rust_assert (ok);
+  tree type = TyTyResolveCompile::compile (ctx, usize);
+
+  tree size = build_int_cstu (type, literal_value.as_string ().size ());
+
+  return ctx->get_backend ()->constructor_expression (fat_pointer, false,
+						      {data, size}, -1,
+						      expr.get_locus ());
+}
+
+tree
+CompileExpr::compile_byte_string_literal (const HIR::LiteralExpr &expr,
+					  const TyTy::BaseType *tyty)
+{
+  rust_assert (expr.get_lit_type () == HIR::Literal::BYTE_STRING);
+
+  // the type here is &[ty; capacity]
+  rust_assert (tyty->get_kind () == TyTy::TypeKind::REF);
+  const auto ref_tyty = static_cast<const TyTy::ReferenceType *> (tyty);
+  auto base_tyty = ref_tyty->get_base ();
+  rust_assert (base_tyty->get_kind () == TyTy::TypeKind::ARRAY);
+  auto array_tyty = static_cast<TyTy::ArrayType *> (base_tyty);
+
+  std::string value_str = expr.get_literal ().as_string ();
+  std::vector<tree> vals;
+  std::vector<unsigned long> indexes;
+  for (size_t i = 0; i < value_str.size (); i++)
+    {
+      char b = value_str.at (i);
+      tree bb = ctx->get_backend ()->char_constant_expression (b);
+      vals.push_back (bb);
+      indexes.push_back (i);
+    }
+
+  tree array_type = TyTyResolveCompile::compile (ctx, array_tyty);
+  tree constructed
+    = ctx->get_backend ()->array_constructor_expression (array_type, indexes,
+							 vals,
+							 expr.get_locus ());
+
+  return address_expression (constructed, expr.get_locus ());
+}
+
+tree
+CompileExpr::type_cast_expression (tree type_to_cast_to, tree expr_tree,
+				   Location location)
+{
+  if (type_to_cast_to == error_mark_node || expr_tree == error_mark_node
+      || TREE_TYPE (expr_tree) == error_mark_node)
+    return error_mark_node;
+
+  if (ctx->get_backend ()->type_size (type_to_cast_to) == 0
+      || TREE_TYPE (expr_tree) == void_type_node)
+    {
+      // Do not convert zero-sized types.
+      return expr_tree;
+    }
+  else if (TREE_CODE (type_to_cast_to) == INTEGER_TYPE)
+    {
+      tree cast = convert_to_integer (type_to_cast_to, expr_tree);
+      // FIXME check for TREE_OVERFLOW?
+      return cast;
+    }
+  else if (TREE_CODE (type_to_cast_to) == REAL_TYPE)
+    {
+      tree cast = convert_to_real (type_to_cast_to, expr_tree);
+      // FIXME
+      // We might need to check that the tree is MAX val and thusly saturate it
+      // to inf. we can get the bounds and check the value if its >= or <= to
+      // the min and max bounds
+      //
+      // https://github.com/Rust-GCC/gccrs/issues/635
+      return cast;
+    }
+  else if (TREE_CODE (type_to_cast_to) == COMPLEX_TYPE)
+    {
+      return convert_to_complex (type_to_cast_to, expr_tree);
+    }
+  else if (TREE_CODE (type_to_cast_to) == POINTER_TYPE
+	   && TREE_CODE (TREE_TYPE (expr_tree)) == INTEGER_TYPE)
+    {
+      return convert_to_pointer (type_to_cast_to, expr_tree);
+    }
+  else if (TREE_CODE (type_to_cast_to) == RECORD_TYPE
+	   || TREE_CODE (type_to_cast_to) == ARRAY_TYPE)
+    {
+      return fold_build1_loc (location.gcc_location (), VIEW_CONVERT_EXPR,
+			      type_to_cast_to, expr_tree);
+    }
+  else if (TREE_CODE (type_to_cast_to) == POINTER_TYPE
+	   && SLICE_TYPE_P (TREE_TYPE (expr_tree)))
+    {
+      // returning a raw cast using NOP_EXPR seems to resut in an ICE:
+      //
+      // Analyzing compilation unit
+      // Performing interprocedural optimizations
+      //  <*free_lang_data> {heap 2644k} <visibility> {heap 2644k}
+      //  <build_ssa_passes> {heap 2644k} <opt_local_passes> {heap 2644k}during
+      //  GIMPLE pass: cddce
+      // In function ‘*T::as_ptr<i32>’:
+      // rust1: internal compiler error: in propagate_necessity, at
+      // tree-ssa-dce.cc:984 0x1d5b43e propagate_necessity
+      //         ../../gccrs/gcc/tree-ssa-dce.cc:984
+      // 0x1d5e180 perform_tree_ssa_dce
+      //         ../../gccrs/gcc/tree-ssa-dce.cc:1876
+      // 0x1d5e2c8 tree_ssa_cd_dce
+      //         ../../gccrs/gcc/tree-ssa-dce.cc:1920
+      // 0x1d5e49a execute
+      //         ../../gccrs/gcc/tree-ssa-dce.cc:1992
+
+      // this is returning the direct raw pointer of the slice an assumes a very
+      // specific layout
+      return ctx->get_backend ()->struct_field_expression (expr_tree, 0,
+							   location);
+    }
+
+  return fold_convert_loc (location.gcc_location (), type_to_cast_to,
+			   expr_tree);
+}
+
+void
+CompileExpr::visit (HIR::ArrayExpr &expr)
+{
+  TyTy::BaseType *tyty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (),
+				       &tyty))
+    {
+      rust_fatal_error (expr.get_locus (),
+			"did not resolve type for this array expr");
+      return;
+    }
+
+  tree array_type = TyTyResolveCompile::compile (ctx, tyty);
+  if (TREE_CODE (array_type) != ARRAY_TYPE)
+    {
+      translated = error_mark_node;
+      return;
+    }
+
+  rust_assert (tyty->get_kind () == TyTy::TypeKind::ARRAY);
+  const TyTy::ArrayType &array_tyty
+    = static_cast<const TyTy::ArrayType &> (*tyty);
+
+  HIR::ArrayElems &elements = *expr.get_internal_elements ();
+  switch (elements.get_array_expr_type ())
+    {
+      case HIR::ArrayElems::ArrayExprType::VALUES: {
+	HIR::ArrayElemsValues &elems
+	  = static_cast<HIR::ArrayElemsValues &> (elements);
+	translated
+	  = array_value_expr (expr.get_locus (), array_tyty, array_type, elems);
+      }
+      return;
+
+    case HIR::ArrayElems::ArrayExprType::COPIED:
+      HIR::ArrayElemsCopied &elems
+	= static_cast<HIR::ArrayElemsCopied &> (elements);
+      translated
+	= array_copied_expr (expr.get_locus (), array_tyty, array_type, elems);
+    }
+}
+
+tree
+CompileExpr::array_value_expr (Location expr_locus,
+			       const TyTy::ArrayType &array_tyty,
+			       tree array_type, HIR::ArrayElemsValues &elems)
+{
+  std::vector<unsigned long> indexes;
+  std::vector<tree> constructor;
+  size_t i = 0;
+  for (auto &elem : elems.get_values ())
+    {
+      tree translated_expr = CompileExpr::Compile (elem.get (), ctx);
+      constructor.push_back (translated_expr);
+      indexes.push_back (i++);
+    }
+
+  return ctx->get_backend ()->array_constructor_expression (array_type, indexes,
+							    constructor,
+							    expr_locus);
+}
+
+tree
+CompileExpr::array_copied_expr (Location expr_locus,
+				const TyTy::ArrayType &array_tyty,
+				tree array_type, HIR::ArrayElemsCopied &elems)
+{
+  //  see gcc/cp/typeck2.cc:1369-1401
+  gcc_assert (TREE_CODE (array_type) == ARRAY_TYPE);
+  tree domain = TYPE_DOMAIN (array_type);
+  if (!domain)
+    return error_mark_node;
+
+  if (!TREE_CONSTANT (TYPE_MAX_VALUE (domain)))
+    {
+      rust_error_at (expr_locus, "non const capacity domain %qT", array_type);
+      return error_mark_node;
+    }
+
+  tree capacity_expr = CompileExpr::Compile (elems.get_num_copies_expr (), ctx);
+  if (!TREE_CONSTANT (capacity_expr))
+    {
+      rust_error_at (expr_locus, "non const num copies %qT", array_type);
+      return error_mark_node;
+    }
+
+  // get the compiled value
+  tree translated_expr = CompileExpr::Compile (elems.get_elem_to_copy (), ctx);
+
+  tree max_domain = TYPE_MAX_VALUE (domain);
+  tree min_domain = TYPE_MIN_VALUE (domain);
+
+  auto max = wi::to_offset (max_domain);
+  auto min = wi::to_offset (min_domain);
+  auto precision = TYPE_PRECISION (TREE_TYPE (domain));
+  auto sign = TYPE_SIGN (TREE_TYPE (domain));
+  unsigned HOST_WIDE_INT len
+    = wi::ext (max - min + 1, precision, sign).to_uhwi ();
+
+  // In a const context we must initialize the entire array, which entails
+  // allocating for each element. If the user wants a huge array, we will OOM
+  // and die horribly.
+  if (ctx->const_context_p ())
+    {
+      size_t idx = 0;
+      std::vector<unsigned long> indexes;
+      std::vector<tree> constructor;
+      for (unsigned HOST_WIDE_INT i = 0; i < len; i++)
+	{
+	  constructor.push_back (translated_expr);
+	  indexes.push_back (idx++);
+	}
+
+      return ctx->get_backend ()->array_constructor_expression (array_type,
+								indexes,
+								constructor,
+								expr_locus);
+    }
+
+  else
+    {
+      // Create a new block scope in which to initialize the array
+      tree fndecl = NULL_TREE;
+      if (ctx->in_fn ())
+	fndecl = ctx->peek_fn ().fndecl;
+
+      std::vector<Bvariable *> locals;
+      tree enclosing_scope = ctx->peek_enclosing_scope ();
+      tree init_block
+	= ctx->get_backend ()->block (fndecl, enclosing_scope, locals,
+				      expr_locus, expr_locus);
+      ctx->push_block (init_block);
+
+      tree tmp;
+      tree stmts
+	= ctx->get_backend ()->array_initializer (fndecl, init_block,
+						  array_type, capacity_expr,
+						  translated_expr, &tmp,
+						  expr_locus);
+      ctx->add_statement (stmts);
+
+      tree block = ctx->pop_block ();
+
+      // The result is a compound expression which creates a temporary array,
+      // initializes all the elements in a loop, and then yeilds the array.
+      return ctx->get_backend ()->compound_expression (block, tmp, expr_locus);
+    }
+}
+
+tree
+HIRCompileBase::resolve_adjustements (
+  std::vector<Resolver::Adjustment> &adjustments, tree expression,
+  Location locus)
+{
+  tree e = expression;
+  for (auto &adjustment : adjustments)
+    {
+      switch (adjustment.get_type ())
+	{
+	case Resolver::Adjustment::AdjustmentType::ERROR:
+	  return error_mark_node;
+
+	case Resolver::Adjustment::AdjustmentType::IMM_REF:
+	  case Resolver::Adjustment::AdjustmentType::MUT_REF: {
+	    if (!SLICE_TYPE_P (TREE_TYPE (e)))
+	      {
+		e = address_expression (e, locus);
+	      }
+	  }
+	  break;
+
+	case Resolver::Adjustment::AdjustmentType::DEREF:
+	case Resolver::Adjustment::AdjustmentType::DEREF_MUT:
+	  e = resolve_deref_adjustment (adjustment, e, locus);
+	  break;
+
+	case Resolver::Adjustment::AdjustmentType::INDIRECTION:
+	  e = resolve_indirection_adjustment (adjustment, e, locus);
+	  break;
+
+	case Resolver::Adjustment::AdjustmentType::UNSIZE:
+	  e = resolve_unsized_adjustment (adjustment, e, locus);
+	  break;
+	}
+    }
+
+  return e;
+}
+
+tree
+HIRCompileBase::resolve_deref_adjustment (Resolver::Adjustment &adjustment,
+					  tree expression, Location locus)
+{
+  rust_assert (adjustment.is_deref_adjustment ()
+	       || adjustment.is_deref_mut_adjustment ());
+  rust_assert (adjustment.has_operator_overload ());
+
+  TyTy::FnType *lookup = adjustment.get_deref_operator_fn ();
+  HIR::ImplItem *resolved_item = adjustment.get_deref_hir_item ();
+
+  tree fn_address = error_mark_node;
+  if (!lookup->has_subsititions_defined ())
+    fn_address = CompileInherentImplItem::Compile (resolved_item, ctx, nullptr,
+						   true, locus);
+  else
+    fn_address = CompileInherentImplItem::Compile (resolved_item, ctx, lookup,
+						   true, locus);
+
+  // does it need a reference to call
+  tree adjusted_argument = expression;
+  bool needs_borrow = adjustment.get_deref_adjustment_type ()
+		      != Resolver::Adjustment::AdjustmentType::ERROR;
+  if (needs_borrow)
+    {
+      adjusted_argument = address_expression (expression, locus);
+    }
+
+  // make the call
+  return ctx->get_backend ()->call_expression (fn_address, {adjusted_argument},
+					       nullptr, locus);
+}
+
+tree
+HIRCompileBase::resolve_indirection_adjustment (
+  Resolver::Adjustment &adjustment, tree expression, Location locus)
+{
+  return indirect_expression (expression, locus);
+}
+
+tree
+HIRCompileBase::resolve_unsized_adjustment (Resolver::Adjustment &adjustment,
+					    tree expression, Location locus)
+{
+  bool expect_slice
+    = adjustment.get_expected ()->get_kind () == TyTy::TypeKind::SLICE;
+  bool expect_dyn
+    = adjustment.get_expected ()->get_kind () == TyTy::TypeKind::DYNAMIC;
+
+  // assumes this is an array
+  tree expr_type = TREE_TYPE (expression);
+  if (expect_slice)
+    {
+      rust_assert (TREE_CODE (expr_type) == ARRAY_TYPE);
+      return resolve_unsized_slice_adjustment (adjustment, expression, locus);
+    }
+
+  rust_assert (expect_dyn);
+  return resolve_unsized_dyn_adjustment (adjustment, expression, locus);
+}
+
+tree
+HIRCompileBase::resolve_unsized_slice_adjustment (
+  Resolver::Adjustment &adjustment, tree expression, Location locus)
+{
+  // assumes this is an array
+  tree expr_type = TREE_TYPE (expression);
+  rust_assert (TREE_CODE (expr_type) == ARRAY_TYPE);
+
+  // takes an array and returns a fat-pointer so this becomes a constructor
+  // expression
+  rust_assert (adjustment.get_expected ()->get_kind ()
+	       == TyTy::TypeKind::SLICE);
+  tree fat_pointer
+    = TyTyResolveCompile::compile (ctx, adjustment.get_expected ());
+
+  // make a constructor for this
+  tree data = address_expression (expression, locus);
+
+  // fetch the size from the domain
+  tree domain = TYPE_DOMAIN (expr_type);
+  unsigned HOST_WIDE_INT array_size
+    = wi::ext (wi::to_offset (TYPE_MAX_VALUE (domain))
+		 - wi::to_offset (TYPE_MIN_VALUE (domain)) + 1,
+	       TYPE_PRECISION (TREE_TYPE (domain)),
+	       TYPE_SIGN (TREE_TYPE (domain)))
+	.to_uhwi ();
+  tree size = build_int_cstu (size_type_node, array_size);
+
+  return ctx->get_backend ()->constructor_expression (fat_pointer, false,
+						      {data, size}, -1, locus);
+}
+
+tree
+HIRCompileBase::resolve_unsized_dyn_adjustment (
+  Resolver::Adjustment &adjustment, tree expression, Location locus)
+{
+  tree rvalue = expression;
+  Location rvalue_locus = locus;
+
+  const TyTy::BaseType *actual = adjustment.get_actual ();
+  const TyTy::BaseType *expected = adjustment.get_expected ();
+
+  const TyTy::DynamicObjectType *dyn
+    = static_cast<const TyTy::DynamicObjectType *> (expected);
+
+  rust_debug ("resolve_unsized_dyn_adjustment actual={%s} dyn={%s}",
+	      actual->debug_str ().c_str (), dyn->debug_str ().c_str ());
+
+  return coerce_to_dyn_object (rvalue, actual, dyn, rvalue_locus);
+}
+
+void
+CompileExpr::visit (HIR::RangeFromToExpr &expr)
+{
+  tree from = CompileExpr::Compile (expr.get_from_expr ().get (), ctx);
+  tree to = CompileExpr::Compile (expr.get_to_expr ().get (), ctx);
+  if (from == error_mark_node || to == error_mark_node)
+    {
+      translated = error_mark_node;
+      return;
+    }
+
+  TyTy::BaseType *tyty = nullptr;
+  bool ok
+    = ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (), &tyty);
+  rust_assert (ok);
+
+  tree adt = TyTyResolveCompile::compile (ctx, tyty);
+
+  // make the constructor
+  translated
+    = ctx->get_backend ()->constructor_expression (adt, false, {from, to}, -1,
+						   expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::RangeFromExpr &expr)
+{
+  tree from = CompileExpr::Compile (expr.get_from_expr ().get (), ctx);
+  if (from == error_mark_node)
+    {
+      translated = error_mark_node;
+      return;
+    }
+
+  TyTy::BaseType *tyty = nullptr;
+  bool ok
+    = ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (), &tyty);
+  rust_assert (ok);
+
+  tree adt = TyTyResolveCompile::compile (ctx, tyty);
+
+  // make the constructor
+  translated
+    = ctx->get_backend ()->constructor_expression (adt, false, {from}, -1,
+						   expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::RangeToExpr &expr)
+{
+  tree to = CompileExpr::Compile (expr.get_to_expr ().get (), ctx);
+  if (to == error_mark_node)
+    {
+      translated = error_mark_node;
+      return;
+    }
+
+  TyTy::BaseType *tyty = nullptr;
+  bool ok
+    = ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (), &tyty);
+  rust_assert (ok);
+
+  tree adt = TyTyResolveCompile::compile (ctx, tyty);
+
+  // make the constructor
+  translated
+    = ctx->get_backend ()->constructor_expression (adt, false, {to}, -1,
+						   expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::RangeFullExpr &expr)
+{
+  TyTy::BaseType *tyty = nullptr;
+  bool ok
+    = ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (), &tyty);
+  rust_assert (ok);
+
+  tree adt = TyTyResolveCompile::compile (ctx, tyty);
+  translated = ctx->get_backend ()->constructor_expression (adt, false, {}, -1,
+							    expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::RangeFromToInclExpr &expr)
+{
+  tree from = CompileExpr::Compile (expr.get_from_expr ().get (), ctx);
+  tree to = CompileExpr::Compile (expr.get_to_expr ().get (), ctx);
+  if (from == error_mark_node || to == error_mark_node)
+    {
+      translated = error_mark_node;
+      return;
+    }
+
+  TyTy::BaseType *tyty = nullptr;
+  bool ok
+    = ctx->get_tyctx ()->lookup_type (expr.get_mappings ().get_hirid (), &tyty);
+  rust_assert (ok);
+
+  tree adt = TyTyResolveCompile::compile (ctx, tyty);
+
+  // make the constructor
+  translated
+    = ctx->get_backend ()->constructor_expression (adt, false, {from, to}, -1,
+						   expr.get_locus ());
+}
+
+void
+CompileExpr::visit (HIR::ArrayIndexExpr &expr)
+{
+  tree array_reference = CompileExpr::Compile (expr.get_array_expr (), ctx);
+  tree index = CompileExpr::Compile (expr.get_index_expr (), ctx);
+
+  // this might be an core::ops::index lang item situation
+  TyTy::FnType *fntype;
+  bool is_op_overload = ctx->get_tyctx ()->lookup_operator_overload (
+    expr.get_mappings ().get_hirid (), &fntype);
+  if (is_op_overload)
+    {
+      auto lang_item_type = Analysis::RustLangItem::ItemType::INDEX;
+      tree operator_overload_call
+	= resolve_operator_overload (lang_item_type, expr, array_reference,
+				     index, expr.get_array_expr (),
+				     expr.get_index_expr ());
+
+      tree actual_type = TREE_TYPE (operator_overload_call);
+      bool can_indirect = TYPE_PTR_P (actual_type) || TYPE_REF_P (actual_type);
+      if (!can_indirect)
+	{
+	  // nothing to do
+	  translated = operator_overload_call;
+	  return;
+	}
+
+      // rust deref always returns a reference from this overload then we can
+      // actually do the indirection
+      translated
+	= indirect_expression (operator_overload_call, expr.get_locus ());
+      return;
+    }
+
+  // lets check if the array is a reference type then we can add an
+  // indirection if required
+  TyTy::BaseType *array_expr_ty = nullptr;
+  bool ok = ctx->get_tyctx ()->lookup_type (
+    expr.get_array_expr ()->get_mappings ().get_hirid (), &array_expr_ty);
+  rust_assert (ok);
+
+  // do we need to add an indirect reference
+  if (array_expr_ty->get_kind () == TyTy::TypeKind::REF)
+    {
+      array_reference
+	= indirect_expression (array_reference, expr.get_locus ());
+    }
+
+  translated
+    = ctx->get_backend ()->array_index_expression (array_reference, index,
+						   expr.get_locus ());
+}
+
+} // namespace Compile
+} // namespace Rust
diff --git a/gcc/rust/backend/rust-compile-expr.h b/gcc/rust/backend/rust-compile-expr.h
new file mode 100644
index 00000000000..4c1f95ade29
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-expr.h
@@ -0,0 +1,148 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_COMPILE_EXPR
+#define RUST_COMPILE_EXPR
+
+#include "rust-compile-base.h"
+
+namespace Rust {
+namespace Compile {
+
+class CompileExpr : private HIRCompileBase, protected HIR::HIRExpressionVisitor
+{
+public:
+  static tree Compile (HIR::Expr *expr, Context *ctx);
+
+  void visit (HIR::TupleIndexExpr &expr) override;
+  void visit (HIR::TupleExpr &expr) override;
+  void visit (HIR::ReturnExpr &expr) override;
+  void visit (HIR::CallExpr &expr) override;
+  void visit (HIR::MethodCallExpr &expr) override;
+  void visit (HIR::LiteralExpr &expr) override;
+  void visit (HIR::AssignmentExpr &expr) override;
+  void visit (HIR::CompoundAssignmentExpr &expr) override;
+  void visit (HIR::ArrayIndexExpr &expr) override;
+  void visit (HIR::ArrayExpr &expr) override;
+  void visit (HIR::ArithmeticOrLogicalExpr &expr) override;
+  void visit (HIR::ComparisonExpr &expr) override;
+  void visit (HIR::LazyBooleanExpr &expr) override;
+  void visit (HIR::NegationExpr &expr) override;
+  void visit (HIR::TypeCastExpr &expr) override;
+  void visit (HIR::IfExpr &expr) override;
+  void visit (HIR::IfExprConseqIf &expr) override;
+  void visit (HIR::IfExprConseqElse &expr) override;
+  void visit (HIR::BlockExpr &expr) override;
+  void visit (HIR::UnsafeBlockExpr &expr) override;
+  void visit (HIR::StructExprStruct &struct_expr) override;
+  void visit (HIR::StructExprStructFields &struct_expr) override;
+  void visit (HIR::GroupedExpr &expr) override;
+  void visit (HIR::FieldAccessExpr &expr) override;
+  void visit (HIR::QualifiedPathInExpression &expr) override;
+  void visit (HIR::PathInExpression &expr) override;
+  void visit (HIR::LoopExpr &expr) override;
+  void visit (HIR::WhileLoopExpr &expr) override;
+  void visit (HIR::BreakExpr &expr) override;
+  void visit (HIR::ContinueExpr &expr) override;
+  void visit (HIR::BorrowExpr &expr) override;
+  void visit (HIR::DereferenceExpr &expr) override;
+  void visit (HIR::MatchExpr &expr) override;
+  void visit (HIR::RangeFromToExpr &expr) override;
+  void visit (HIR::RangeFromExpr &expr) override;
+  void visit (HIR::RangeToExpr &expr) override;
+  void visit (HIR::RangeFullExpr &expr) override;
+  void visit (HIR::RangeFromToInclExpr &expr) override;
+
+  // Empty visit for unused Expression HIR nodes.
+  void visit (HIR::ClosureExprInner &) override {}
+  void visit (HIR::ClosureExprInnerTyped &) override {}
+  void visit (HIR::StructExprFieldIdentifier &) override {}
+  void visit (HIR::StructExprFieldIdentifierValue &) override {}
+  void visit (HIR::StructExprFieldIndexValue &) override {}
+  void visit (HIR::ErrorPropagationExpr &) override {}
+  void visit (HIR::RangeToInclExpr &) override {}
+  void visit (HIR::WhileLetLoopExpr &) override {}
+  void visit (HIR::ForLoopExpr &) override {}
+  void visit (HIR::IfExprConseqIfLet &) override {}
+  void visit (HIR::IfLetExpr &) override {}
+  void visit (HIR::IfLetExprConseqElse &) override {}
+  void visit (HIR::IfLetExprConseqIf &) override {}
+  void visit (HIR::IfLetExprConseqIfLet &) override {}
+  void visit (HIR::AwaitExpr &) override {}
+  void visit (HIR::AsyncBlockExpr &) override {}
+
+protected:
+  tree get_fn_addr_from_dyn (const TyTy::DynamicObjectType *dyn,
+			     TyTy::BaseType *receiver, TyTy::FnType *fntype,
+			     tree receiver_ref, Location expr_locus);
+
+  tree get_receiver_from_dyn (const TyTy::DynamicObjectType *dyn,
+			      TyTy::BaseType *receiver, TyTy::FnType *fntype,
+			      tree receiver_ref, Location expr_locus);
+
+  tree resolve_method_address (TyTy::FnType *fntype, HirId ref,
+			       TyTy::BaseType *receiver,
+			       HIR::PathIdentSegment &segment,
+			       Analysis::NodeMapping expr_mappings,
+			       Location expr_locus);
+
+  tree
+  resolve_operator_overload (Analysis::RustLangItem::ItemType lang_item_type,
+			     HIR::OperatorExprMeta expr, tree lhs, tree rhs,
+			     HIR::Expr *lhs_expr, HIR::Expr *rhs_expr);
+
+  tree compile_bool_literal (const HIR::LiteralExpr &expr,
+			     const TyTy::BaseType *tyty);
+
+  tree compile_integer_literal (const HIR::LiteralExpr &expr,
+				const TyTy::BaseType *tyty);
+
+  tree compile_float_literal (const HIR::LiteralExpr &expr,
+			      const TyTy::BaseType *tyty);
+
+  tree compile_char_literal (const HIR::LiteralExpr &expr,
+			     const TyTy::BaseType *tyty);
+
+  tree compile_byte_literal (const HIR::LiteralExpr &expr,
+			     const TyTy::BaseType *tyty);
+
+  tree compile_string_literal (const HIR::LiteralExpr &expr,
+			       const TyTy::BaseType *tyty);
+
+  tree compile_byte_string_literal (const HIR::LiteralExpr &expr,
+				    const TyTy::BaseType *tyty);
+
+  tree type_cast_expression (tree type_to_cast_to, tree expr, Location locus);
+
+  tree array_value_expr (Location expr_locus, const TyTy::ArrayType &array_tyty,
+			 tree array_type, HIR::ArrayElemsValues &elems);
+
+  tree array_copied_expr (Location expr_locus,
+			  const TyTy::ArrayType &array_tyty, tree array_type,
+			  HIR::ArrayElemsCopied &elems);
+
+private:
+  CompileExpr (Context *ctx);
+
+  tree translated;
+};
+
+} // namespace Compile
+} // namespace Rust
+
+#endif // RUST_COMPILE_EXPR
diff --git a/gcc/rust/backend/rust-compile-extern.h b/gcc/rust/backend/rust-compile-extern.h
new file mode 100644
index 00000000000..45a507e03be
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-extern.h
@@ -0,0 +1,172 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_COMPILE_EXTERN_ITEM
+#define RUST_COMPILE_EXTERN_ITEM
+
+#include "rust-compile-base.h"
+#include "rust-compile-intrinsic.h"
+
+namespace Rust {
+namespace Compile {
+
+class CompileExternItem : public HIRCompileBase,
+			  public HIR::HIRExternalItemVisitor
+{
+public:
+  static tree compile (HIR::ExternalItem *item, Context *ctx,
+		       TyTy::BaseType *concrete = nullptr,
+		       bool is_query_mode = false,
+		       Location ref_locus = Location ())
+  {
+    CompileExternItem compiler (ctx, concrete, ref_locus);
+    item->accept_vis (compiler);
+
+    if (is_query_mode && compiler.reference == error_mark_node)
+      rust_internal_error_at (ref_locus, "failed to compile extern item: %s",
+			      item->as_string ().c_str ());
+
+    return compiler.reference;
+  }
+
+  void visit (HIR::ExternalStaticItem &item) override
+  {
+    // check if its already been compiled
+    Bvariable *lookup = ctx->get_backend ()->error_variable ();
+    if (ctx->lookup_var_decl (item.get_mappings ().get_hirid (), &lookup))
+      {
+	reference = ctx->get_backend ()->var_expression (lookup, ref_locus);
+	return;
+      }
+
+    TyTy::BaseType *resolved_type = nullptr;
+    bool ok = ctx->get_tyctx ()->lookup_type (item.get_mappings ().get_hirid (),
+					      &resolved_type);
+    rust_assert (ok);
+
+    std::string name = item.get_item_name ();
+    // FIXME this is assuming C ABI
+    std::string asm_name = name;
+
+    tree type = TyTyResolveCompile::compile (ctx, resolved_type);
+    bool is_external = true;
+    bool is_hidden = false;
+    bool in_unique_section = false;
+
+    Bvariable *static_global
+      = ctx->get_backend ()->global_variable (name, asm_name, type, is_external,
+					      is_hidden, in_unique_section,
+					      item.get_locus ());
+    ctx->insert_var_decl (item.get_mappings ().get_hirid (), static_global);
+    ctx->push_var (static_global);
+
+    reference = ctx->get_backend ()->var_expression (static_global, ref_locus);
+  }
+
+  void visit (HIR::ExternalFunctionItem &function) override
+  {
+    TyTy::BaseType *fntype_tyty;
+    if (!ctx->get_tyctx ()->lookup_type (function.get_mappings ().get_hirid (),
+					 &fntype_tyty))
+      {
+	rust_fatal_error (function.get_locus (),
+			  "failed to lookup function type");
+	return;
+      }
+
+    rust_assert (fntype_tyty->get_kind () == TyTy::TypeKind::FNDEF);
+    TyTy::FnType *fntype = static_cast<TyTy::FnType *> (fntype_tyty);
+    if (fntype->has_subsititions_defined ())
+      {
+	// we cant do anything for this only when it is used and a concrete type
+	// is given
+	if (concrete == nullptr)
+	  return;
+	else
+	  {
+	    rust_assert (concrete->get_kind () == TyTy::TypeKind::FNDEF);
+	    fntype = static_cast<TyTy::FnType *> (concrete);
+	  }
+      }
+
+    // items can be forward compiled which means we may not need to invoke this
+    // code. We might also have already compiled this generic function as well.
+    tree lookup = NULL_TREE;
+    if (ctx->lookup_function_decl (fntype->get_ty_ref (), &lookup,
+				   fntype->get_id (), fntype))
+      {
+	reference = address_expression (lookup, ref_locus);
+	return;
+      }
+
+    if (fntype->has_subsititions_defined ())
+      {
+	// override the Hir Lookups for the substituions in this context
+	fntype->override_context ();
+      }
+
+    if (fntype->get_abi () == ABI::INTRINSIC)
+      {
+	Intrinsics compile (ctx);
+	tree fndecl = compile.compile (fntype);
+	ctx->insert_function_decl (fntype, fndecl);
+	return;
+      }
+
+    tree compiled_fn_type = TyTyResolveCompile::compile (ctx, fntype);
+    std::string ir_symbol_name = function.get_item_name ();
+    std::string asm_name = function.get_item_name ();
+    if (fntype->get_abi () == ABI::RUST)
+      {
+	// then we need to get the canonical path of it and mangle it
+	const Resolver::CanonicalPath *canonical_path = nullptr;
+	bool ok = ctx->get_mappings ()->lookup_canonical_path (
+	  function.get_mappings ().get_nodeid (), &canonical_path);
+	rust_assert (ok);
+
+	ir_symbol_name = canonical_path->get () + fntype->subst_as_string ();
+	asm_name = ctx->mangle_item (fntype, *canonical_path);
+      }
+
+    const unsigned int flags = Backend::function_is_declaration;
+    tree fndecl
+      = ctx->get_backend ()->function (compiled_fn_type, ir_symbol_name,
+				       asm_name, flags, function.get_locus ());
+    TREE_PUBLIC (fndecl) = 1;
+    setup_abi_options (fndecl, fntype->get_abi ());
+
+    ctx->insert_function_decl (fntype, fndecl);
+
+    reference = address_expression (fndecl, ref_locus);
+  }
+
+private:
+  CompileExternItem (Context *ctx, TyTy::BaseType *concrete, Location ref_locus)
+    : HIRCompileBase (ctx), concrete (concrete), reference (error_mark_node),
+      ref_locus (ref_locus)
+  {}
+
+  TyTy::BaseType *concrete;
+  tree reference;
+  Location ref_locus;
+};
+
+} // namespace Compile
+} // namespace Rust
+
+#endif // RUST_COMPILE_EXTERN_ITEM
diff --git a/gcc/rust/backend/rust-compile-fnparam.cc b/gcc/rust/backend/rust-compile-fnparam.cc
new file mode 100644
index 00000000000..3f0ec82b625
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-fnparam.cc
@@ -0,0 +1,121 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-compile-fnparam.h"
+#include "rust-compile-pattern.h"
+
+#include "gimple-expr.h"
+
+namespace Rust {
+namespace Compile {
+
+CompileFnParam::CompileFnParam (Context *ctx, tree fndecl, tree decl_type,
+				Location locus)
+  : HIRCompileBase (ctx), fndecl (fndecl), decl_type (decl_type), locus (locus),
+    compiled_param (ctx->get_backend ()->error_variable ())
+{}
+
+Bvariable *
+CompileFnParam::compile (Context *ctx, tree fndecl, HIR::FunctionParam *param,
+			 tree decl_type, Location locus)
+{
+  CompileFnParam compiler (ctx, fndecl, decl_type, locus);
+  param->get_param_name ()->accept_vis (compiler);
+  return compiler.compiled_param;
+}
+
+Bvariable *
+CompileFnParam::compile (Context *ctx, tree fndecl, HIR::Pattern *param,
+			 tree decl_type, Location locus)
+{
+  CompileFnParam compiler (ctx, fndecl, decl_type, locus);
+  param->accept_vis (compiler);
+  return compiler.compiled_param;
+}
+
+void
+CompileFnParam::visit (HIR::IdentifierPattern &pattern)
+{
+  if (!pattern.is_mut ())
+    decl_type = ctx->get_backend ()->immutable_type (decl_type);
+
+  compiled_param
+    = ctx->get_backend ()->parameter_variable (fndecl,
+					       pattern.get_identifier (),
+					       decl_type, locus);
+}
+
+void
+CompileFnParam::visit (HIR::WildcardPattern &pattern)
+{
+  decl_type = ctx->get_backend ()->immutable_type (decl_type);
+
+  compiled_param
+    = ctx->get_backend ()->parameter_variable (fndecl, "_", decl_type, locus);
+}
+
+void
+CompileFnParam::visit (HIR::StructPattern &pattern)
+{
+  // generate the anon param
+  tree tmp_ident = create_tmp_var_name ("RSTPRM");
+  std::string cpp_str_identifier = std::string (IDENTIFIER_POINTER (tmp_ident));
+
+  decl_type = ctx->get_backend ()->immutable_type (decl_type);
+  compiled_param
+    = ctx->get_backend ()->parameter_variable (fndecl, cpp_str_identifier,
+					       decl_type, locus);
+
+  // setup the pattern bindings
+  tree anon_param = ctx->get_backend ()->var_expression (compiled_param, locus);
+  CompilePatternBindings::Compile (&pattern, anon_param, ctx);
+}
+
+void
+CompileFnParam::visit (HIR::TupleStructPattern &pattern)
+{
+  // generate the anon param
+  tree tmp_ident = create_tmp_var_name ("RSTPRM");
+  std::string cpp_str_identifier = std::string (IDENTIFIER_POINTER (tmp_ident));
+
+  decl_type = ctx->get_backend ()->immutable_type (decl_type);
+  compiled_param
+    = ctx->get_backend ()->parameter_variable (fndecl, cpp_str_identifier,
+					       decl_type, locus);
+
+  // setup the pattern bindings
+  tree anon_param = ctx->get_backend ()->var_expression (compiled_param, locus);
+  CompilePatternBindings::Compile (&pattern, anon_param, ctx);
+}
+
+Bvariable *
+CompileSelfParam::compile (Context *ctx, tree fndecl, HIR::SelfParam &self,
+			   tree decl_type, Location locus)
+{
+  bool is_immutable
+    = self.get_self_kind () == HIR::SelfParam::ImplicitSelfKind::IMM
+      || self.get_self_kind () == HIR::SelfParam::ImplicitSelfKind::IMM_REF;
+  if (is_immutable)
+    decl_type = ctx->get_backend ()->immutable_type (decl_type);
+
+  return ctx->get_backend ()->parameter_variable (fndecl, "self", decl_type,
+						  locus);
+}
+
+} // namespace Compile
+} // namespace Rust
diff --git a/gcc/rust/backend/rust-compile-fnparam.h b/gcc/rust/backend/rust-compile-fnparam.h
new file mode 100644
index 00000000000..0dbbd99ef08
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-fnparam.h
@@ -0,0 +1,70 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_COMPILE_FNPARAM
+#define RUST_COMPILE_FNPARAM
+
+#include "rust-compile-base.h"
+
+namespace Rust {
+namespace Compile {
+
+class CompileFnParam : private HIRCompileBase, protected HIR::HIRPatternVisitor
+{
+public:
+  static Bvariable *compile (Context *ctx, tree fndecl,
+			     HIR::FunctionParam *param, tree decl_type,
+			     Location locus);
+  static Bvariable *compile (Context *ctx, tree fndecl, HIR::Pattern *param,
+			     tree decl_type, Location locus);
+
+  void visit (HIR::IdentifierPattern &pattern) override;
+  void visit (HIR::WildcardPattern &pattern) override;
+  void visit (HIR::StructPattern &) override;
+  void visit (HIR::TupleStructPattern &) override;
+
+  // Empty visit for unused Pattern HIR nodes.
+  void visit (HIR::GroupedPattern &) override {}
+  void visit (HIR::LiteralPattern &) override {}
+  void visit (HIR::PathInExpression &) override {}
+  void visit (HIR::QualifiedPathInExpression &) override {}
+  void visit (HIR::RangePattern &) override {}
+  void visit (HIR::ReferencePattern &) override {}
+  void visit (HIR::SlicePattern &) override {}
+  void visit (HIR::TuplePattern &) override {}
+
+private:
+  CompileFnParam (Context *ctx, tree fndecl, tree decl_type, Location locus);
+
+  tree fndecl;
+  tree decl_type;
+  Location locus;
+  Bvariable *compiled_param;
+};
+
+class CompileSelfParam : private HIRCompileBase
+{
+public:
+  static Bvariable *compile (Context *ctx, tree fndecl, HIR::SelfParam &self,
+			     tree decl_type, Location locus);
+};
+
+} // namespace Compile
+} // namespace Rust
+
+#endif // RUST_COMPILE_FNPARAM
diff --git a/gcc/rust/backend/rust-compile-implitem.cc b/gcc/rust/backend/rust-compile-implitem.cc
new file mode 100644
index 00000000000..d0f70a70228
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-implitem.cc
@@ -0,0 +1,101 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-compile-implitem.h"
+#include "rust-compile-expr.h"
+#include "rust-compile-fnparam.h"
+
+namespace Rust {
+namespace Compile {
+
+void
+CompileTraitItem::visit (HIR::TraitItemConst &constant)
+{
+  rust_assert (concrete != nullptr);
+  TyTy::BaseType *resolved_type = concrete;
+
+  const Resolver::CanonicalPath *canonical_path = nullptr;
+  bool ok = ctx->get_mappings ()->lookup_canonical_path (
+    constant.get_mappings ().get_nodeid (), &canonical_path);
+  rust_assert (ok);
+
+  HIR::Expr *const_value_expr = constant.get_expr ().get ();
+  tree const_expr
+    = compile_constant_item (ctx, resolved_type, canonical_path,
+			     const_value_expr, constant.get_locus ());
+  ctx->push_const (const_expr);
+  ctx->insert_const_decl (constant.get_mappings ().get_hirid (), const_expr);
+
+  reference = const_expr;
+}
+
+void
+CompileTraitItem::visit (HIR::TraitItemFunc &func)
+{
+  rust_assert (func.has_block_defined ());
+
+  rust_assert (concrete->get_kind () == TyTy::TypeKind::FNDEF);
+  TyTy::FnType *fntype = static_cast<TyTy::FnType *> (concrete);
+  fntype->monomorphize ();
+
+  // items can be forward compiled which means we may not need to invoke this
+  // code. We might also have already compiled this generic function as well.
+  tree lookup = NULL_TREE;
+  if (ctx->lookup_function_decl (fntype->get_ty_ref (), &lookup,
+				 fntype->get_id (), fntype))
+    {
+      // has this been added to the list then it must be finished
+      if (ctx->function_completed (lookup))
+	{
+	  tree dummy = NULL_TREE;
+	  if (!ctx->lookup_function_decl (fntype->get_ty_ref (), &dummy))
+	    {
+	      ctx->insert_function_decl (fntype, lookup);
+	    }
+
+	  reference = address_expression (lookup, ref_locus);
+	  return;
+	}
+    }
+
+  if (fntype->has_subsititions_defined ())
+    {
+      // override the Hir Lookups for the substituions in this context
+      fntype->override_context ();
+    }
+
+  const Resolver::CanonicalPath *canonical_path = nullptr;
+  bool ok = ctx->get_mappings ()->lookup_canonical_path (
+    func.get_mappings ().get_nodeid (), &canonical_path);
+  rust_assert (ok);
+
+  // FIXME: How do we get the proper visibility here?
+  auto vis = HIR::Visibility (HIR::Visibility::VisType::PUBLIC);
+  HIR::TraitFunctionDecl &function = func.get_decl ();
+  tree fndecl
+    = compile_function (ctx, function.get_function_name (),
+			function.get_self (), function.get_function_params (),
+			function.get_qualifiers (), vis,
+			func.get_outer_attrs (), func.get_locus (),
+			func.get_block_expr ().get (), canonical_path, fntype,
+			function.has_return_type ());
+  reference = address_expression (fndecl, ref_locus);
+}
+
+} // namespace Compile
+} // namespace Rust
diff --git a/gcc/rust/backend/rust-compile-implitem.h b/gcc/rust/backend/rust-compile-implitem.h
new file mode 100644
index 00000000000..ac9478af150
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-implitem.h
@@ -0,0 +1,91 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_COMPILE_IMPLITEM_H
+#define RUST_COMPILE_IMPLITEM_H
+
+#include "rust-compile-item.h"
+#include "rust-compile-expr.h"
+#include "rust-compile-fnparam.h"
+
+namespace Rust {
+namespace Compile {
+
+// this is a proxy for HIR::ImplItem's back to use the normel HIR::Item path
+class CompileInherentImplItem : public CompileItem
+{
+public:
+  static tree Compile (HIR::ImplItem *item, Context *ctx,
+		       TyTy::BaseType *concrete = nullptr,
+		       bool is_query_mode = false,
+		       Location ref_locus = Location ())
+  {
+    CompileInherentImplItem compiler (ctx, concrete, ref_locus);
+    item->accept_vis (compiler);
+
+    if (is_query_mode && compiler.reference == error_mark_node)
+      rust_internal_error_at (ref_locus, "failed to compile impl item: %s",
+			      item->as_string ().c_str ());
+
+    return compiler.reference;
+  }
+
+private:
+  CompileInherentImplItem (Context *ctx, TyTy::BaseType *concrete,
+			   Location ref_locus)
+    : CompileItem (ctx, concrete, ref_locus)
+  {}
+};
+
+class CompileTraitItem : public HIRCompileBase, public HIR::HIRTraitItemVisitor
+{
+public:
+  static tree Compile (HIR::TraitItem *item, Context *ctx,
+		       TyTy::BaseType *concrete, bool is_query_mode = false,
+		       Location ref_locus = Location ())
+  {
+    CompileTraitItem compiler (ctx, concrete, ref_locus);
+    item->accept_vis (compiler);
+
+    if (is_query_mode && compiler.reference == error_mark_node)
+      rust_internal_error_at (ref_locus, "failed to compile trait item: %s",
+			      item->as_string ().c_str ());
+
+    return compiler.reference;
+  }
+
+  void visit (HIR::TraitItemConst &constant) override;
+  void visit (HIR::TraitItemFunc &func) override;
+
+  void visit (HIR::TraitItemType &typ) override {}
+
+private:
+  CompileTraitItem (Context *ctx, TyTy::BaseType *concrete, Location ref_locus)
+    : HIRCompileBase (ctx), concrete (concrete), reference (error_mark_node),
+      ref_locus (ref_locus)
+  {}
+
+  TyTy::BaseType *concrete;
+  tree reference;
+  Location ref_locus;
+};
+
+} // namespace Compile
+} // namespace Rust
+
+#endif // RUST_COMPILE_IMPLITEM_H
diff --git a/gcc/rust/backend/rust-compile-intrinsic.cc b/gcc/rust/backend/rust-compile-intrinsic.cc
new file mode 100644
index 00000000000..61084b90f33
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-intrinsic.cc
@@ -0,0 +1,515 @@
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-compile-intrinsic.h"
+#include "fold-const.h"
+#include "langhooks.h"
+#include "rust-compile-context.h"
+#include "rust-compile-type.h"
+#include "rust-compile-fnparam.h"
+#include "rust-builtins.h"
+#include "rust-diagnostics.h"
+#include "rust-location.h"
+#include "rust-tree.h"
+#include "tree-core.h"
+#include "print-tree.h"
+
+namespace Rust {
+namespace Compile {
+
+static tree
+offset_handler (Context *ctx, TyTy::FnType *fntype);
+static tree
+sizeof_handler (Context *ctx, TyTy::FnType *fntype);
+static tree
+transmute_handler (Context *ctx, TyTy::FnType *fntype);
+static tree
+rotate_handler (Context *ctx, TyTy::FnType *fntype, tree_code op);
+static tree
+wrapping_op_handler (Context *ctx, TyTy::FnType *fntype, tree_code op);
+static tree
+copy_nonoverlapping_handler (Context *ctx, TyTy::FnType *fntype);
+
+static inline tree
+rotate_left_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  return rotate_handler (ctx, fntype, LROTATE_EXPR);
+}
+static inline tree
+rotate_right_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  return rotate_handler (ctx, fntype, RROTATE_EXPR);
+}
+
+static inline tree
+wrapping_add_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  return wrapping_op_handler (ctx, fntype, PLUS_EXPR);
+}
+static inline tree
+wrapping_sub_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  return wrapping_op_handler (ctx, fntype, MINUS_EXPR);
+}
+static inline tree
+wrapping_mul_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  return wrapping_op_handler (ctx, fntype, MULT_EXPR);
+}
+
+static const std::map<std::string,
+		      std::function<tree (Context *, TyTy::FnType *)>>
+  generic_intrinsics = {{"offset", &offset_handler},
+			{"size_of", &sizeof_handler},
+			{"transmute", &transmute_handler},
+			{"rotate_left", &rotate_left_handler},
+			{"rotate_right", &rotate_right_handler},
+			{"wrapping_add", &wrapping_add_handler},
+			{"wrapping_sub", &wrapping_sub_handler},
+			{"wrapping_mul", &wrapping_mul_handler},
+			{"copy_nonoverlapping", &copy_nonoverlapping_handler}};
+
+Intrinsics::Intrinsics (Context *ctx) : ctx (ctx) {}
+
+tree
+Intrinsics::compile (TyTy::FnType *fntype)
+{
+  rust_assert (fntype->get_abi () == ABI::INTRINSIC);
+
+  tree builtin = error_mark_node;
+  BuiltinsContext &builtin_ctx = BuiltinsContext::get ();
+  if (builtin_ctx.lookup_simple_builtin (fntype->get_identifier (), &builtin))
+    return builtin;
+
+  // is it an generic builtin?
+  auto it = generic_intrinsics.find (fntype->get_identifier ());
+  if (it != generic_intrinsics.end ())
+    return it->second (ctx, fntype);
+
+  Location locus = ctx->get_mappings ()->lookup_location (fntype->get_ref ());
+  rust_error_at (locus, "unknown builtin intrinsic: %s",
+		 fntype->get_identifier ().c_str ());
+
+  return error_mark_node;
+}
+
+/**
+ * Items can be forward compiled which means we may not need to invoke this
+ * code. We might also have already compiled this generic function as well.
+ */
+static bool
+check_for_cached_intrinsic (Context *ctx, TyTy::FnType *fntype, tree *lookup)
+{
+  if (ctx->lookup_function_decl (fntype->get_ty_ref (), lookup,
+				 fntype->get_id (), fntype))
+    {
+      // Has this been added to the list? Then it must be finished
+      if (ctx->function_completed (*lookup))
+	{
+	  tree dummy = NULL_TREE;
+	  if (!ctx->lookup_function_decl (fntype->get_ty_ref (), &dummy))
+	    ctx->insert_function_decl (fntype, *lookup);
+	  return true;
+	}
+    }
+
+  return false;
+}
+
+/**
+ * Maybe override the Hir Lookups for the substituions in this context
+ */
+static void
+maybe_override_ctx (TyTy::FnType *fntype)
+{
+  if (fntype->has_subsititions_defined ())
+    fntype->override_context ();
+}
+
+/**
+ * Compile and setup a function's parameters
+ */
+static void
+compile_fn_params (Context *ctx, TyTy::FnType *fntype, tree fndecl,
+		   std::vector<Bvariable *> *compiled_param_variables,
+		   std::vector<tree_node *> *compiled_param_types = nullptr)
+{
+  for (auto &parm : fntype->get_params ())
+    {
+      auto &referenced_param = parm.first;
+      auto &param_tyty = parm.second;
+      auto compiled_param_type = TyTyResolveCompile::compile (ctx, param_tyty);
+
+      Location param_locus = referenced_param->get_locus ();
+      Bvariable *compiled_param_var
+	= CompileFnParam::compile (ctx, fndecl, referenced_param,
+				   compiled_param_type, param_locus);
+
+      compiled_param_variables->push_back (compiled_param_var);
+      if (compiled_param_types)
+	compiled_param_types->push_back (compiled_param_type);
+    }
+}
+
+static tree
+compile_intrinsic_function (Context *ctx, TyTy::FnType *fntype)
+{
+  maybe_override_ctx (fntype);
+
+  const Resolver::CanonicalPath &canonical_path = fntype->get_ident ().path;
+
+  tree compiled_fn_type = TyTyResolveCompile::compile (ctx, fntype);
+  std::string ir_symbol_name
+    = canonical_path.get () + fntype->subst_as_string ();
+  std::string asm_name = ctx->mangle_item (fntype, canonical_path);
+
+  unsigned int flags = 0;
+  tree fndecl
+    = ctx->get_backend ()->function (compiled_fn_type, ir_symbol_name, asm_name,
+				     flags, fntype->get_ident ().locus);
+
+  TREE_PUBLIC (fndecl) = 0;
+  TREE_READONLY (fndecl) = 1;
+  DECL_ARTIFICIAL (fndecl) = 1;
+  DECL_EXTERNAL (fndecl) = 0;
+  DECL_DECLARED_INLINE_P (fndecl) = 1;
+
+  return fndecl;
+}
+
+static void
+enter_intrinsic_block (Context *ctx, tree fndecl)
+{
+  tree enclosing_scope = NULL_TREE;
+  Location start_location = Location ();
+  Location end_location = Location ();
+
+  auto block = ctx->get_backend ()->block (fndecl, enclosing_scope, {},
+					   start_location, end_location);
+
+  ctx->push_block (block);
+}
+
+static void
+finalize_intrinsic_block (Context *ctx, tree fndecl)
+{
+  tree bind_tree = ctx->pop_block ();
+
+  gcc_assert (TREE_CODE (bind_tree) == BIND_EXPR);
+
+  DECL_SAVED_TREE (fndecl) = bind_tree;
+
+  ctx->push_function (fndecl);
+}
+
+static tree
+offset_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  // offset intrinsic has two params dst pointer and offset isize
+  rust_assert (fntype->get_params ().size () == 2);
+
+  auto fndecl = compile_intrinsic_function (ctx, fntype);
+
+  std::vector<Bvariable *> param_vars;
+  compile_fn_params (ctx, fntype, fndecl, &param_vars);
+
+  auto &dst_param = param_vars.at (0);
+  auto &size_param = param_vars.at (1);
+  rust_assert (param_vars.size () == 2);
+  if (!ctx->get_backend ()->function_set_parameters (fndecl, param_vars))
+    return error_mark_node;
+
+  enter_intrinsic_block (ctx, fndecl);
+
+  // BUILTIN offset FN BODY BEGIN
+  tree dst = ctx->get_backend ()->var_expression (dst_param, Location ());
+  tree size = ctx->get_backend ()->var_expression (size_param, Location ());
+  tree pointer_offset_expr
+    = pointer_offset_expression (dst, size, BUILTINS_LOCATION);
+  auto return_statement
+    = ctx->get_backend ()->return_statement (fndecl, {pointer_offset_expr},
+					     Location ());
+  ctx->add_statement (return_statement);
+  // BUILTIN offset FN BODY END
+
+  finalize_intrinsic_block (ctx, fndecl);
+
+  return fndecl;
+}
+
+static tree
+sizeof_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  // size_of has _zero_ parameters its parameter is the generic one
+  rust_assert (fntype->get_params ().size () == 0);
+
+  tree lookup = NULL_TREE;
+  if (check_for_cached_intrinsic (ctx, fntype, &lookup))
+    return lookup;
+
+  auto fndecl = compile_intrinsic_function (ctx, fntype);
+
+  // get the template parameter type tree fn size_of<T>();
+  rust_assert (fntype->get_num_substitutions () == 1);
+  auto &param_mapping = fntype->get_substs ().at (0);
+  const TyTy::ParamType *param_tyty = param_mapping.get_param_ty ();
+  TyTy::BaseType *resolved_tyty = param_tyty->resolve ();
+  tree template_parameter_type
+    = TyTyResolveCompile::compile (ctx, resolved_tyty);
+
+  enter_intrinsic_block (ctx, fndecl);
+
+  // BUILTIN size_of FN BODY BEGIN
+  tree size_expr = TYPE_SIZE_UNIT (template_parameter_type);
+  auto return_statement
+    = ctx->get_backend ()->return_statement (fndecl, {size_expr}, Location ());
+  ctx->add_statement (return_statement);
+  // BUILTIN size_of FN BODY END
+
+  finalize_intrinsic_block (ctx, fndecl);
+
+  return fndecl;
+}
+
+static tree
+transmute_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  // transmute intrinsic has one parameter
+  rust_assert (fntype->get_params ().size () == 1);
+
+  tree lookup = NULL_TREE;
+  if (check_for_cached_intrinsic (ctx, fntype, &lookup))
+    return lookup;
+
+  auto fndecl = compile_intrinsic_function (ctx, fntype);
+
+  std::vector<Bvariable *> param_vars;
+  std::vector<tree_node *> compiled_types;
+  compile_fn_params (ctx, fntype, fndecl, &param_vars, &compiled_types);
+
+  if (!ctx->get_backend ()->function_set_parameters (fndecl, param_vars))
+    return error_mark_node;
+
+  // param to convert
+  Bvariable *convert_me_param = param_vars.at (0);
+  tree convert_me_expr
+    = ctx->get_backend ()->var_expression (convert_me_param, Location ());
+
+  // check for transmute pre-conditions
+  tree target_type_expr = TREE_TYPE (DECL_RESULT (fndecl));
+  tree source_type_expr = compiled_types.at (0);
+  tree target_size_expr = TYPE_SIZE (target_type_expr);
+  tree source_size_expr = TYPE_SIZE (source_type_expr);
+  // for some reason, unit types and other zero-sized types return NULL for the
+  // size expressions
+  unsigned HOST_WIDE_INT target_size
+    = target_size_expr ? TREE_INT_CST_LOW (target_size_expr) : 0;
+  unsigned HOST_WIDE_INT source_size
+    = source_size_expr ? TREE_INT_CST_LOW (source_size_expr) : 0;
+
+  // size check for concrete types
+  // TODO(liushuyu): check alignment for pointers; check for dependently-sized
+  // types
+  if (target_size != source_size)
+    {
+      rust_error_at (fntype->get_locus (),
+		     "cannot transmute between types of different sizes, or "
+		     "dependently-sized types");
+      rust_inform (fntype->get_ident ().locus, "source type: %qs (%lu bits)",
+		   fntype->get_params ().at (0).second->as_string ().c_str (),
+		   (unsigned long) source_size);
+      rust_inform (fntype->get_ident ().locus, "target type: %qs (%lu bits)",
+		   fntype->get_return_type ()->as_string ().c_str (),
+		   (unsigned long) target_size);
+    }
+
+  enter_intrinsic_block (ctx, fndecl);
+
+  // BUILTIN transmute FN BODY BEGIN
+
+  // Return *((orig_type*)&decl)  */
+
+  tree t
+    = build_fold_addr_expr_loc (Location ().gcc_location (), convert_me_expr);
+  t = fold_build1_loc (Location ().gcc_location (), NOP_EXPR,
+		       build_pointer_type (target_type_expr), t);
+  tree result_expr
+    = build_fold_indirect_ref_loc (Location ().gcc_location (), t);
+
+  auto return_statement
+    = ctx->get_backend ()->return_statement (fndecl, {result_expr},
+					     Location ());
+  ctx->add_statement (return_statement);
+  // BUILTIN transmute FN BODY END
+
+  finalize_intrinsic_block (ctx, fndecl);
+
+  return fndecl;
+}
+
+static tree
+rotate_handler (Context *ctx, TyTy::FnType *fntype, tree_code op)
+{
+  // rotate intrinsic has two parameter
+  rust_assert (fntype->get_params ().size () == 2);
+
+  tree lookup = NULL_TREE;
+  if (check_for_cached_intrinsic (ctx, fntype, &lookup))
+    return lookup;
+
+  auto fndecl = compile_intrinsic_function (ctx, fntype);
+
+  // setup the params
+  std::vector<Bvariable *> param_vars;
+  compile_fn_params (ctx, fntype, fndecl, &param_vars);
+
+  auto &x_param = param_vars.at (0);
+  auto &y_param = param_vars.at (1);
+  rust_assert (param_vars.size () == 2);
+  if (!ctx->get_backend ()->function_set_parameters (fndecl, param_vars))
+    return error_mark_node;
+
+  enter_intrinsic_block (ctx, fndecl);
+
+  // BUILTIN rotate FN BODY BEGIN
+  tree x = ctx->get_backend ()->var_expression (x_param, Location ());
+  tree y = ctx->get_backend ()->var_expression (y_param, Location ());
+  tree rotate_expr
+    = fold_build2_loc (BUILTINS_LOCATION, op, TREE_TYPE (x), x, y);
+  auto return_statement
+    = ctx->get_backend ()->return_statement (fndecl, {rotate_expr},
+					     Location ());
+  ctx->add_statement (return_statement);
+  // BUILTIN rotate FN BODY END
+
+  finalize_intrinsic_block (ctx, fndecl);
+
+  return fndecl;
+}
+
+/**
+ * pub fn wrapping_{add, sub, mul}<T>(lhs: T, rhs: T) -> T;
+ */
+static tree
+wrapping_op_handler (Context *ctx, TyTy::FnType *fntype, tree_code op)
+{
+  // wrapping_<op> intrinsics have two parameter
+  rust_assert (fntype->get_params ().size () == 2);
+
+  tree lookup = NULL_TREE;
+  if (check_for_cached_intrinsic (ctx, fntype, &lookup))
+    return lookup;
+
+  auto fndecl = compile_intrinsic_function (ctx, fntype);
+
+  // setup the params
+  std::vector<Bvariable *> param_vars;
+  compile_fn_params (ctx, fntype, fndecl, &param_vars);
+
+  auto &lhs_param = param_vars.at (0);
+  auto &rhs_param = param_vars.at (1);
+
+  if (!ctx->get_backend ()->function_set_parameters (fndecl, param_vars))
+    return error_mark_node;
+
+  enter_intrinsic_block (ctx, fndecl);
+
+  // BUILTIN wrapping_<op> FN BODY BEGIN
+  auto lhs = ctx->get_backend ()->var_expression (lhs_param, Location ());
+  auto rhs = ctx->get_backend ()->var_expression (rhs_param, Location ());
+
+  // Operations are always wrapping in Rust, as we have -fwrapv enabled by
+  // default. The difference between a wrapping_{add, sub, mul} and a regular
+  // arithmetic operation is that these intrinsics do not panic - they always
+  // carry over.
+  auto wrap_expr = build2 (op, TREE_TYPE (lhs), lhs, rhs);
+
+  auto return_statement
+    = ctx->get_backend ()->return_statement (fndecl, {wrap_expr}, Location ());
+  ctx->add_statement (return_statement);
+  // BUILTIN wrapping_<op> FN BODY END
+
+  finalize_intrinsic_block (ctx, fndecl);
+
+  return fndecl;
+}
+
+/**
+ * fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
+ */
+static tree
+copy_nonoverlapping_handler (Context *ctx, TyTy::FnType *fntype)
+{
+  rust_assert (fntype->get_params ().size () == 3);
+  rust_assert (fntype->get_num_substitutions () == 1);
+
+  tree lookup = NULL_TREE;
+  if (check_for_cached_intrinsic (ctx, fntype, &lookup))
+    return lookup;
+
+  auto fndecl = compile_intrinsic_function (ctx, fntype);
+
+  // Most intrinsic functions are pure - not `copy_nonoverlapping`
+  TREE_READONLY (fndecl) = 0;
+  TREE_SIDE_EFFECTS (fndecl) = 1;
+
+  // setup the params
+  std::vector<Bvariable *> param_vars;
+  compile_fn_params (ctx, fntype, fndecl, &param_vars);
+
+  if (!ctx->get_backend ()->function_set_parameters (fndecl, param_vars))
+    return error_mark_node;
+
+  enter_intrinsic_block (ctx, fndecl);
+
+  // BUILTIN copy_nonoverlapping BODY BEGIN
+
+  auto src = ctx->get_backend ()->var_expression (param_vars[0], Location ());
+  auto dst = ctx->get_backend ()->var_expression (param_vars[1], Location ());
+  auto count = ctx->get_backend ()->var_expression (param_vars[2], Location ());
+
+  // We want to create the following statement
+  // memcpy(dst, src, size_of::<T>());
+  // so
+  // memcpy(dst, src, size_expr);
+
+  auto *resolved_ty = fntype->get_substs ().at (0).get_param_ty ()->resolve ();
+  auto param_type = TyTyResolveCompile::compile (ctx, resolved_ty);
+
+  tree size_expr
+    = build2 (MULT_EXPR, size_type_node, TYPE_SIZE_UNIT (param_type), count);
+
+  tree memcpy_raw = nullptr;
+  BuiltinsContext::get ().lookup_simple_builtin ("memcpy", &memcpy_raw);
+  rust_assert (memcpy_raw);
+  auto memcpy
+    = build_fold_addr_expr_loc (Location ().gcc_location (), memcpy_raw);
+
+  auto copy_call
+    = ctx->get_backend ()->call_expression (memcpy, {dst, src, size_expr},
+					    nullptr, Location ());
+
+  ctx->add_statement (copy_call);
+
+  // BUILTIN copy_nonoverlapping BODY END
+
+  finalize_intrinsic_block (ctx, fndecl);
+
+  return fndecl;
+}
+
+} // namespace Compile
+} // namespace Rust
diff --git a/gcc/rust/backend/rust-compile-intrinsic.h b/gcc/rust/backend/rust-compile-intrinsic.h
new file mode 100644
index 00000000000..dceb0864fd4
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-intrinsic.h
@@ -0,0 +1,40 @@
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_COMPILE_INTRINSIC
+#define RUST_COMPILE_INTRINSIC
+
+#include "rust-compile-context.h"
+#include "langhooks.h"
+
+namespace Rust {
+namespace Compile {
+
+class Intrinsics
+{
+public:
+  Intrinsics (Context *ctx);
+
+  tree compile (TyTy::FnType *fntype);
+
+private:
+  Context *ctx;
+};
+
+} // namespace Compile
+} // namespace Rust
+
+#endif // RUST_COMPILE_INTRINSIC
diff --git a/gcc/rust/backend/rust-compile-item.cc b/gcc/rust/backend/rust-compile-item.cc
new file mode 100644
index 00000000000..ceba51c2d27
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-item.cc
@@ -0,0 +1,206 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-compile-item.h"
+#include "rust-compile-implitem.h"
+#include "rust-compile-expr.h"
+#include "rust-compile-extern.h"
+#include "rust-constexpr.h"
+
+namespace Rust {
+namespace Compile {
+
+void
+CompileItem::visit (HIR::StaticItem &var)
+{
+  // have we already compiled this?
+  Bvariable *static_decl_ref = nullptr;
+  if (ctx->lookup_var_decl (var.get_mappings ().get_hirid (), &static_decl_ref))
+    {
+      reference
+	= ctx->get_backend ()->var_expression (static_decl_ref, ref_locus);
+      return;
+    }
+
+  TyTy::BaseType *resolved_type = nullptr;
+  bool ok = ctx->get_tyctx ()->lookup_type (var.get_mappings ().get_hirid (),
+					    &resolved_type);
+  rust_assert (ok);
+
+  tree type = TyTyResolveCompile::compile (ctx, resolved_type);
+  tree value = CompileExpr::Compile (var.get_expr (), ctx);
+
+  const Resolver::CanonicalPath *canonical_path = nullptr;
+  ok = ctx->get_mappings ()->lookup_canonical_path (
+    var.get_mappings ().get_nodeid (), &canonical_path);
+  rust_assert (ok);
+
+  std::string name = canonical_path->get ();
+  std::string asm_name = ctx->mangle_item (resolved_type, *canonical_path);
+
+  bool is_external = false;
+  bool is_hidden = false;
+  bool in_unique_section = true;
+
+  Bvariable *static_global
+    = ctx->get_backend ()->global_variable (name, asm_name, type, is_external,
+					    is_hidden, in_unique_section,
+					    var.get_locus ());
+  ctx->get_backend ()->global_variable_set_init (static_global, value);
+
+  ctx->insert_var_decl (var.get_mappings ().get_hirid (), static_global);
+  ctx->push_var (static_global);
+
+  reference = ctx->get_backend ()->var_expression (static_global, ref_locus);
+}
+
+void
+CompileItem::visit (HIR::ConstantItem &constant)
+{
+  if (ctx->lookup_const_decl (constant.get_mappings ().get_hirid (),
+			      &reference))
+    return;
+
+  // resolve the type
+  TyTy::BaseType *resolved_type = nullptr;
+  bool ok
+    = ctx->get_tyctx ()->lookup_type (constant.get_mappings ().get_hirid (),
+				      &resolved_type);
+  rust_assert (ok);
+
+  // canonical path
+  const Resolver::CanonicalPath *canonical_path = nullptr;
+  ok = ctx->get_mappings ()->lookup_canonical_path (
+    constant.get_mappings ().get_nodeid (), &canonical_path);
+  rust_assert (ok);
+
+  HIR::Expr *const_value_expr = constant.get_expr ();
+  ctx->push_const_context ();
+  tree const_expr
+    = compile_constant_item (ctx, resolved_type, canonical_path,
+			     const_value_expr, constant.get_locus ());
+  ctx->pop_const_context ();
+
+  ctx->push_const (const_expr);
+  ctx->insert_const_decl (constant.get_mappings ().get_hirid (), const_expr);
+  reference = const_expr;
+}
+
+void
+CompileItem::visit (HIR::Function &function)
+{
+  TyTy::BaseType *fntype_tyty;
+  if (!ctx->get_tyctx ()->lookup_type (function.get_mappings ().get_hirid (),
+				       &fntype_tyty))
+    {
+      rust_fatal_error (function.get_locus (),
+			"failed to lookup function type");
+      return;
+    }
+
+  rust_assert (fntype_tyty->get_kind () == TyTy::TypeKind::FNDEF);
+  TyTy::FnType *fntype = static_cast<TyTy::FnType *> (fntype_tyty);
+  if (fntype->has_subsititions_defined ())
+    {
+      // we cant do anything for this only when it is used and a concrete type
+      // is given
+      if (concrete == nullptr)
+	return;
+      else
+	{
+	  rust_assert (concrete->get_kind () == TyTy::TypeKind::FNDEF);
+	  fntype = static_cast<TyTy::FnType *> (concrete);
+	  fntype->monomorphize ();
+	}
+    }
+
+  // items can be forward compiled which means we may not need to invoke this
+  // code. We might also have already compiled this generic function as well.
+  tree lookup = NULL_TREE;
+  if (ctx->lookup_function_decl (fntype->get_ty_ref (), &lookup,
+				 fntype->get_id (), fntype))
+    {
+      // has this been added to the list then it must be finished
+      if (ctx->function_completed (lookup))
+	{
+	  tree dummy = NULL_TREE;
+	  if (!ctx->lookup_function_decl (fntype->get_ty_ref (), &dummy))
+	    {
+	      ctx->insert_function_decl (fntype, lookup);
+	    }
+
+	  reference = address_expression (lookup, ref_locus);
+	  return;
+	}
+    }
+
+  if (fntype->has_subsititions_defined ())
+    {
+      // override the Hir Lookups for the substituions in this context
+      fntype->override_context ();
+    }
+
+  const Resolver::CanonicalPath *canonical_path = nullptr;
+  bool ok = ctx->get_mappings ()->lookup_canonical_path (
+    function.get_mappings ().get_nodeid (), &canonical_path);
+  rust_assert (ok);
+
+  tree fndecl
+    = compile_function (ctx, function.get_function_name (),
+			function.get_self_param (),
+			function.get_function_params (),
+			function.get_qualifiers (), function.get_visibility (),
+			function.get_outer_attrs (), function.get_locus (),
+			function.get_definition ().get (), canonical_path,
+			fntype, function.has_function_return_type ());
+  reference = address_expression (fndecl, ref_locus);
+}
+
+void
+CompileItem::visit (HIR::ImplBlock &impl_block)
+{
+  TyTy::BaseType *self_lookup = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (
+	impl_block.get_type ()->get_mappings ().get_hirid (), &self_lookup))
+    {
+      rust_error_at (impl_block.get_locus (), "failed to resolve type of impl");
+      return;
+    }
+
+  for (auto &impl_item : impl_block.get_impl_items ())
+    CompileInherentImplItem::Compile (impl_item.get (), ctx);
+}
+
+void
+CompileItem::visit (HIR::ExternBlock &extern_block)
+{
+  for (auto &item : extern_block.get_extern_items ())
+    {
+      CompileExternItem::compile (item.get (), ctx, concrete);
+    }
+}
+
+void
+CompileItem::visit (HIR::Module &module)
+{
+  for (auto &item : module.get_items ())
+    CompileItem::compile (item.get (), ctx);
+}
+
+} // namespace Compile
+} // namespace Rust
diff --git a/gcc/rust/backend/rust-compile-item.h b/gcc/rust/backend/rust-compile-item.h
new file mode 100644
index 00000000000..3c12f1040fc
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-item.h
@@ -0,0 +1,88 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_COMPILE_ITEM
+#define RUST_COMPILE_ITEM
+
+#include "rust-compile-base.h"
+
+namespace Rust {
+namespace Compile {
+
+class CompileItem : private HIRCompileBase, protected HIR::HIRStmtVisitor
+{
+protected:
+public:
+  static tree compile (HIR::Item *item, Context *ctx,
+		       TyTy::BaseType *concrete = nullptr,
+		       bool is_query_mode = false,
+		       Location ref_locus = Location ())
+  {
+    CompileItem compiler (ctx, concrete, ref_locus);
+    item->accept_vis (compiler);
+
+    if (is_query_mode && compiler.reference == error_mark_node)
+      rust_internal_error_at (ref_locus, "failed to compile item: %s",
+			      item->as_string ().c_str ());
+
+    return compiler.reference;
+  }
+
+  void visit (HIR::StaticItem &var) override;
+  void visit (HIR::ConstantItem &constant) override;
+  void visit (HIR::Function &function) override;
+  void visit (HIR::ImplBlock &impl_block) override;
+  void visit (HIR::ExternBlock &extern_block) override;
+  void visit (HIR::Module &module) override;
+
+  // Empty visit for unused Stmt HIR nodes.
+  void visit (HIR::TupleStruct &) override {}
+  void visit (HIR::EnumItem &) override {}
+  void visit (HIR::EnumItemTuple &) override {}
+  void visit (HIR::EnumItemStruct &) override {}
+  void visit (HIR::EnumItemDiscriminant &) override {}
+  void visit (HIR::TypePathSegmentFunction &) override {}
+  void visit (HIR::TypePath &) override {}
+  void visit (HIR::QualifiedPathInType &) override {}
+  void visit (HIR::ExternCrate &) override {}
+  void visit (HIR::UseDeclaration &) override {}
+  void visit (HIR::TypeAlias &) override {}
+  void visit (HIR::StructStruct &) override {}
+  void visit (HIR::Enum &) override {}
+  void visit (HIR::Union &) override {}
+  void visit (HIR::Trait &) override {}
+  void visit (HIR::EmptyStmt &) override {}
+  void visit (HIR::LetStmt &) override {}
+  void visit (HIR::ExprStmtWithoutBlock &) override {}
+  void visit (HIR::ExprStmtWithBlock &) override {}
+
+protected:
+  CompileItem (Context *ctx, TyTy::BaseType *concrete, Location ref_locus)
+    : HIRCompileBase (ctx), concrete (concrete), reference (error_mark_node),
+      ref_locus (ref_locus)
+  {}
+
+  TyTy::BaseType *concrete;
+  tree reference;
+  Location ref_locus;
+};
+
+} // namespace Compile
+} // namespace Rust
+
+#endif // RUST_COMPILE_ITEM
diff --git a/gcc/rust/backend/rust-compile-pattern.cc b/gcc/rust/backend/rust-compile-pattern.cc
new file mode 100644
index 00000000000..1d8eda1a577
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-pattern.cc
@@ -0,0 +1,333 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-compile-pattern.h"
+#include "rust-compile-expr.h"
+#include "rust-compile-resolve-path.h"
+#include "rust-constexpr.h"
+
+namespace Rust {
+namespace Compile {
+
+void
+CompilePatternCaseLabelExpr::visit (HIR::PathInExpression &pattern)
+{
+  // lookup the type
+  TyTy::BaseType *lookup = nullptr;
+  bool ok
+    = ctx->get_tyctx ()->lookup_type (pattern.get_mappings ().get_hirid (),
+				      &lookup);
+  rust_assert (ok);
+
+  // this must be an enum
+  rust_assert (lookup->get_kind () == TyTy::TypeKind::ADT);
+  TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (lookup);
+  rust_assert (adt->is_enum ());
+
+  // lookup the variant
+  HirId variant_id;
+  ok = ctx->get_tyctx ()->lookup_variant_definition (
+    pattern.get_mappings ().get_hirid (), &variant_id);
+  rust_assert (ok);
+
+  TyTy::VariantDef *variant = nullptr;
+  ok = adt->lookup_variant_by_id (variant_id, &variant);
+  rust_assert (ok);
+
+  HIR::Expr *discrim_expr = variant->get_discriminant ();
+  tree discrim_expr_node = CompileExpr::Compile (discrim_expr, ctx);
+  tree folded_discrim_expr = fold_expr (discrim_expr_node);
+  tree case_low = folded_discrim_expr;
+
+  case_label_expr
+    = build_case_label (case_low, NULL_TREE, associated_case_label);
+}
+
+void
+CompilePatternCaseLabelExpr::visit (HIR::StructPattern &pattern)
+{
+  CompilePatternCaseLabelExpr::visit (pattern.get_path ());
+}
+
+void
+CompilePatternCaseLabelExpr::visit (HIR::TupleStructPattern &pattern)
+{
+  CompilePatternCaseLabelExpr::visit (pattern.get_path ());
+}
+
+void
+CompilePatternCaseLabelExpr::visit (HIR::WildcardPattern &pattern)
+{
+  // operand 0 being NULL_TREE signifies this is the default case label see:
+  // tree.def for documentation for CASE_LABEL_EXPR
+  case_label_expr
+    = build_case_label (NULL_TREE, NULL_TREE, associated_case_label);
+}
+
+void
+CompilePatternCaseLabelExpr::visit (HIR::LiteralPattern &pattern)
+{
+  // Compile the literal
+  HIR::LiteralExpr *litexpr
+    = new HIR::LiteralExpr (pattern.get_pattern_mappings (),
+			    pattern.get_literal (), pattern.get_locus (),
+			    std::vector<AST::Attribute> ());
+
+  // Note: Floating point literals are currently accepted but will likely be
+  // forbidden in LiteralPatterns in a future version of Rust.
+  // See: https://github.com/rust-lang/rust/issues/41620
+  // For now, we cannot compile them anyway as CASE_LABEL_EXPR does not support
+  // floating point types.
+  if (pattern.get_literal ().get_lit_type () == HIR::Literal::LitType::FLOAT)
+    {
+      rust_sorry_at (pattern.get_locus (), "floating-point literal in pattern");
+    }
+
+  tree lit = CompileExpr::Compile (litexpr, ctx);
+
+  case_label_expr = build_case_label (lit, NULL_TREE, associated_case_label);
+}
+
+static tree
+compile_range_pattern_bound (HIR::RangePatternBound *bound,
+			     Analysis::NodeMapping mappings, Location locus,
+			     Context *ctx)
+{
+  tree result = NULL_TREE;
+  switch (bound->get_bound_type ())
+    {
+      case HIR::RangePatternBound::RangePatternBoundType::LITERAL: {
+	HIR::RangePatternBoundLiteral &ref
+	  = *static_cast<HIR::RangePatternBoundLiteral *> (bound);
+
+	HIR::LiteralExpr *litexpr
+	  = new HIR::LiteralExpr (mappings, ref.get_literal (), locus,
+				  std::vector<AST::Attribute> ());
+
+	result = CompileExpr::Compile (litexpr, ctx);
+      }
+      break;
+
+      case HIR::RangePatternBound::RangePatternBoundType::PATH: {
+	HIR::RangePatternBoundPath &ref
+	  = *static_cast<HIR::RangePatternBoundPath *> (bound);
+
+	result = ResolvePathRef::Compile (ref.get_path (), ctx);
+
+	// If the path resolves to a const expression, fold it.
+	result = fold_expr (result);
+      }
+      break;
+
+      case HIR::RangePatternBound::RangePatternBoundType::QUALPATH: {
+	HIR::RangePatternBoundQualPath &ref
+	  = *static_cast<HIR::RangePatternBoundQualPath *> (bound);
+
+	result = ResolvePathRef::Compile (ref.get_qualified_path (), ctx);
+
+	// If the path resolves to a const expression, fold it.
+	result = fold_expr (result);
+      }
+    }
+
+  return result;
+}
+
+void
+CompilePatternCaseLabelExpr::visit (HIR::RangePattern &pattern)
+{
+  tree upper = compile_range_pattern_bound (pattern.get_upper_bound ().get (),
+					    pattern.get_pattern_mappings (),
+					    pattern.get_locus (), ctx);
+  tree lower = compile_range_pattern_bound (pattern.get_lower_bound ().get (),
+					    pattern.get_pattern_mappings (),
+					    pattern.get_locus (), ctx);
+
+  case_label_expr = build_case_label (lower, upper, associated_case_label);
+}
+
+// setup the bindings
+
+void
+CompilePatternBindings::visit (HIR::TupleStructPattern &pattern)
+{
+  // lookup the type
+  TyTy::BaseType *lookup = nullptr;
+  bool ok = ctx->get_tyctx ()->lookup_type (
+    pattern.get_path ().get_mappings ().get_hirid (), &lookup);
+  rust_assert (ok);
+
+  // this must be an enum
+  rust_assert (lookup->get_kind () == TyTy::TypeKind::ADT);
+  TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (lookup);
+  rust_assert (adt->number_of_variants () > 0);
+
+  int variant_index = 0;
+  TyTy::VariantDef *variant = adt->get_variants ().at (0);
+  if (adt->is_enum ())
+    {
+      HirId variant_id = UNKNOWN_HIRID;
+      bool ok = ctx->get_tyctx ()->lookup_variant_definition (
+	pattern.get_path ().get_mappings ().get_hirid (), &variant_id);
+      rust_assert (ok);
+
+      ok = adt->lookup_variant_by_id (variant_id, &variant, &variant_index);
+      rust_assert (ok);
+    }
+
+  rust_assert (variant->get_variant_type ()
+	       == TyTy::VariantDef::VariantType::TUPLE);
+
+  std::unique_ptr<HIR::TupleStructItems> &items = pattern.get_items ();
+  switch (items->get_item_type ())
+    {
+      case HIR::TupleStructItems::RANGE: {
+	// TODO
+	gcc_unreachable ();
+      }
+      break;
+
+      case HIR::TupleStructItems::NO_RANGE: {
+	HIR::TupleStructItemsNoRange &items_no_range
+	  = static_cast<HIR::TupleStructItemsNoRange &> (*items.get ());
+
+	rust_assert (items_no_range.get_patterns ().size ()
+		     == variant->num_fields ());
+
+	if (adt->is_enum ())
+	  {
+	    // we are offsetting by + 1 here since the first field in the record
+	    // is always the discriminator
+	    size_t tuple_field_index = 1;
+	    for (auto &pattern : items_no_range.get_patterns ())
+	      {
+		tree variant_accessor
+		  = ctx->get_backend ()->struct_field_expression (
+		    match_scrutinee_expr, variant_index, pattern->get_locus ());
+
+		tree binding = ctx->get_backend ()->struct_field_expression (
+		  variant_accessor, tuple_field_index++, pattern->get_locus ());
+
+		ctx->insert_pattern_binding (
+		  pattern->get_pattern_mappings ().get_hirid (), binding);
+	      }
+	  }
+	else
+	  {
+	    size_t tuple_field_index = 0;
+	    for (auto &pattern : items_no_range.get_patterns ())
+	      {
+		tree variant_accessor = match_scrutinee_expr;
+
+		tree binding = ctx->get_backend ()->struct_field_expression (
+		  variant_accessor, tuple_field_index++, pattern->get_locus ());
+
+		ctx->insert_pattern_binding (
+		  pattern->get_pattern_mappings ().get_hirid (), binding);
+	      }
+	  }
+      }
+      break;
+    }
+}
+
+void
+CompilePatternBindings::visit (HIR::StructPattern &pattern)
+{
+  // lookup the type
+  TyTy::BaseType *lookup = nullptr;
+  bool ok = ctx->get_tyctx ()->lookup_type (
+    pattern.get_path ().get_mappings ().get_hirid (), &lookup);
+  rust_assert (ok);
+
+  // this must be an enum
+  rust_assert (lookup->get_kind () == TyTy::TypeKind::ADT);
+  TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (lookup);
+  rust_assert (adt->number_of_variants () > 0);
+
+  int variant_index = 0;
+  TyTy::VariantDef *variant = adt->get_variants ().at (0);
+  if (adt->is_enum ())
+    {
+      HirId variant_id = UNKNOWN_HIRID;
+      bool ok = ctx->get_tyctx ()->lookup_variant_definition (
+	pattern.get_path ().get_mappings ().get_hirid (), &variant_id);
+      rust_assert (ok);
+
+      ok = adt->lookup_variant_by_id (variant_id, &variant, &variant_index);
+      rust_assert (ok);
+    }
+
+  rust_assert (variant->get_variant_type ()
+	       == TyTy::VariantDef::VariantType::STRUCT);
+
+  auto &struct_pattern_elems = pattern.get_struct_pattern_elems ();
+  for (auto &field : struct_pattern_elems.get_struct_pattern_fields ())
+    {
+      switch (field->get_item_type ())
+	{
+	  case HIR::StructPatternField::ItemType::TUPLE_PAT: {
+	    // TODO
+	    gcc_unreachable ();
+	  }
+	  break;
+
+	  case HIR::StructPatternField::ItemType::IDENT_PAT: {
+	    // TODO
+	    gcc_unreachable ();
+	  }
+	  break;
+
+	  case HIR::StructPatternField::ItemType::IDENT: {
+	    HIR::StructPatternFieldIdent &ident
+	      = static_cast<HIR::StructPatternFieldIdent &> (*field.get ());
+
+	    size_t offs = 0;
+	    ok
+	      = variant->lookup_field (ident.get_identifier (), nullptr, &offs);
+	    rust_assert (ok);
+
+	    tree binding = error_mark_node;
+	    if (adt->is_enum ())
+	      {
+		tree variant_accessor
+		  = ctx->get_backend ()->struct_field_expression (
+		    match_scrutinee_expr, variant_index, ident.get_locus ());
+
+		// we are offsetting by + 1 here since the first field in the
+		// record is always the discriminator
+		binding = ctx->get_backend ()->struct_field_expression (
+		  variant_accessor, offs + 1, ident.get_locus ());
+	      }
+	    else
+	      {
+		tree variant_accessor = match_scrutinee_expr;
+		binding = ctx->get_backend ()->struct_field_expression (
+		  variant_accessor, offs, ident.get_locus ());
+	      }
+
+	    ctx->insert_pattern_binding (ident.get_mappings ().get_hirid (),
+					 binding);
+	  }
+	  break;
+	}
+    }
+}
+
+} // namespace Compile
+} // namespace Rust
diff --git a/gcc/rust/backend/rust-compile-pattern.h b/gcc/rust/backend/rust-compile-pattern.h
new file mode 100644
index 00000000000..0eb5d61249b
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-pattern.h
@@ -0,0 +1,95 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-compile-base.h"
+
+namespace Rust {
+namespace Compile {
+
+class CompilePatternCaseLabelExpr : public HIRCompileBase,
+				    public HIR::HIRPatternVisitor
+{
+public:
+  static tree Compile (HIR::Pattern *pattern, tree associated_case_label,
+		       Context *ctx)
+  {
+    CompilePatternCaseLabelExpr compiler (ctx, associated_case_label);
+    pattern->accept_vis (compiler);
+    return compiler.case_label_expr;
+  }
+
+  void visit (HIR::PathInExpression &pattern) override;
+  void visit (HIR::StructPattern &pattern) override;
+  void visit (HIR::TupleStructPattern &pattern) override;
+  void visit (HIR::WildcardPattern &pattern) override;
+  void visit (HIR::RangePattern &pattern) override;
+
+  // Empty visit for unused Pattern HIR nodes.
+  void visit (HIR::GroupedPattern &) override {}
+  void visit (HIR::IdentifierPattern &) override {}
+  void visit (HIR::LiteralPattern &) override;
+  void visit (HIR::QualifiedPathInExpression &) override {}
+  void visit (HIR::ReferencePattern &) override {}
+  void visit (HIR::SlicePattern &) override {}
+  void visit (HIR::TuplePattern &) override {}
+
+  CompilePatternCaseLabelExpr (Context *ctx, tree associated_case_label)
+    : HIRCompileBase (ctx), case_label_expr (error_mark_node),
+      associated_case_label (associated_case_label)
+  {}
+
+  tree case_label_expr;
+  tree associated_case_label;
+};
+
+class CompilePatternBindings : public HIRCompileBase,
+			       public HIR::HIRPatternVisitor
+{
+public:
+  static void Compile (HIR::Pattern *pattern, tree match_scrutinee_expr,
+		       Context *ctx)
+  {
+    CompilePatternBindings compiler (ctx, match_scrutinee_expr);
+    pattern->accept_vis (compiler);
+  }
+
+  void visit (HIR::StructPattern &pattern) override;
+  void visit (HIR::TupleStructPattern &pattern) override;
+
+  // Empty visit for unused Pattern HIR nodes.
+  void visit (HIR::GroupedPattern &) override {}
+  void visit (HIR::IdentifierPattern &) override {}
+  void visit (HIR::LiteralPattern &) override {}
+  void visit (HIR::PathInExpression &) override {}
+  void visit (HIR::QualifiedPathInExpression &) override {}
+  void visit (HIR::RangePattern &) override {}
+  void visit (HIR::ReferencePattern &) override {}
+  void visit (HIR::SlicePattern &) override {}
+  void visit (HIR::TuplePattern &) override {}
+  void visit (HIR::WildcardPattern &) override {}
+
+protected:
+  CompilePatternBindings (Context *ctx, tree match_scrutinee_expr)
+    : HIRCompileBase (ctx), match_scrutinee_expr (match_scrutinee_expr)
+  {}
+
+  tree match_scrutinee_expr;
+};
+
+} // namespace Compile
+} // namespace Rust
diff --git a/gcc/rust/backend/rust-compile-resolve-path.cc b/gcc/rust/backend/rust-compile-resolve-path.cc
new file mode 100644
index 00000000000..4fb3d540257
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-resolve-path.cc
@@ -0,0 +1,301 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-compile-resolve-path.h"
+#include "rust-compile-intrinsic.h"
+#include "rust-compile-item.h"
+#include "rust-compile-implitem.h"
+#include "rust-compile-expr.h"
+#include "rust-hir-trait-resolve.h"
+#include "rust-hir-path-probe.h"
+#include "rust-compile-extern.h"
+#include "rust-constexpr.h"
+
+namespace Rust {
+namespace Compile {
+
+void
+ResolvePathRef::visit (HIR::QualifiedPathInExpression &expr)
+{
+  resolved = resolve (expr.get_final_segment ().get_segment (),
+		      expr.get_mappings (), expr.get_locus (), true);
+}
+
+void
+ResolvePathRef::visit (HIR::PathInExpression &expr)
+{
+  resolved = resolve (expr.get_final_segment ().get_segment (),
+		      expr.get_mappings (), expr.get_locus (), false);
+}
+
+tree
+ResolvePathRef::resolve (const HIR::PathIdentSegment &final_segment,
+			 const Analysis::NodeMapping &mappings,
+			 Location expr_locus, bool is_qualified_path)
+{
+  TyTy::BaseType *lookup = nullptr;
+  bool ok = ctx->get_tyctx ()->lookup_type (mappings.get_hirid (), &lookup);
+  rust_assert (ok);
+
+  // need to look up the reference for this identifier
+  NodeId ref_node_id = UNKNOWN_NODEID;
+  if (!ctx->get_resolver ()->lookup_resolved_name (mappings.get_nodeid (),
+						   &ref_node_id))
+    {
+      // this can fail because it might be a Constructor for something
+      // in that case the caller should attempt ResolvePathType::Compile
+
+      // it might be an enum data-less enum variant
+      if (lookup->get_kind () != TyTy::TypeKind::ADT)
+	return error_mark_node;
+
+      TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (lookup);
+
+      // it might be a unit-struct
+      if (adt->is_unit ())
+	{
+	  return ctx->get_backend ()->unit_expression ();
+	}
+
+      if (!adt->is_enum ())
+	return error_mark_node;
+
+      HirId variant_id;
+      if (!ctx->get_tyctx ()->lookup_variant_definition (mappings.get_hirid (),
+							 &variant_id))
+	return error_mark_node;
+
+      int union_disriminator = -1;
+      TyTy::VariantDef *variant = nullptr;
+      if (!adt->lookup_variant_by_id (variant_id, &variant,
+				      &union_disriminator))
+	return error_mark_node;
+
+      // this can only be for discriminant variants the others are built up
+      // using call-expr or struct-init
+      rust_assert (variant->get_variant_type ()
+		   == TyTy::VariantDef::VariantType::NUM);
+
+      // we need the actual gcc type
+      tree compiled_adt_type = TyTyResolveCompile::compile (ctx, adt);
+
+      // make the ctor for the union
+      HIR::Expr *discrim_expr = variant->get_discriminant ();
+      tree discrim_expr_node = CompileExpr::Compile (discrim_expr, ctx);
+      tree folded_discrim_expr = fold_expr (discrim_expr_node);
+      tree qualifier = folded_discrim_expr;
+
+      return ctx->get_backend ()->constructor_expression (compiled_adt_type,
+							  true, {qualifier},
+							  union_disriminator,
+							  expr_locus);
+    }
+
+  HirId ref;
+  if (!ctx->get_mappings ()->lookup_node_to_hir (ref_node_id, &ref))
+    {
+      rust_error_at (expr_locus, "reverse call path lookup failure");
+      return error_mark_node;
+    }
+
+  // might be a constant
+  tree constant_expr;
+  if (ctx->lookup_const_decl (ref, &constant_expr))
+    {
+      TREE_USED (constant_expr) = 1;
+      return constant_expr;
+    }
+
+  // this might be a variable reference or a function reference
+  Bvariable *var = nullptr;
+  if (ctx->lookup_var_decl (ref, &var))
+    {
+      // TREE_USED is setup in the gcc abstraction here
+      return ctx->get_backend ()->var_expression (var, expr_locus);
+    }
+
+  // might be a match pattern binding
+  tree binding = error_mark_node;
+  if (ctx->lookup_pattern_binding (ref, &binding))
+    {
+      TREE_USED (binding) = 1;
+      return binding;
+    }
+
+  // it might be a function call
+  if (lookup->get_kind () == TyTy::TypeKind::FNDEF)
+    {
+      TyTy::FnType *fntype = static_cast<TyTy::FnType *> (lookup);
+      tree fn = NULL_TREE;
+      if (ctx->lookup_function_decl (fntype->get_ty_ref (), &fn))
+	{
+	  TREE_USED (fn) = 1;
+	  return address_expression (fn, expr_locus);
+	}
+      else if (fntype->get_abi () == ABI::INTRINSIC)
+	{
+	  Intrinsics compile (ctx);
+	  fn = compile.compile (fntype);
+	  TREE_USED (fn) = 1;
+	  return address_expression (fn, expr_locus);
+	}
+    }
+
+  // let the query system figure it out
+  tree resolved_item = query_compile (ref, lookup, final_segment, mappings,
+				      expr_locus, is_qualified_path);
+  if (resolved_item != error_mark_node)
+    {
+      TREE_USED (resolved_item) = 1;
+    }
+  return resolved_item;
+}
+
+tree
+HIRCompileBase::query_compile (HirId ref, TyTy::BaseType *lookup,
+			       const HIR::PathIdentSegment &final_segment,
+			       const Analysis::NodeMapping &mappings,
+			       Location expr_locus, bool is_qualified_path)
+{
+  HIR::Item *resolved_item = ctx->get_mappings ()->lookup_hir_item (ref);
+  HirId parent_block;
+  HIR::ExternalItem *resolved_extern_item
+    = ctx->get_mappings ()->lookup_hir_extern_item (ref, &parent_block);
+  bool is_hir_item = resolved_item != nullptr;
+  bool is_hir_extern_item = resolved_extern_item != nullptr;
+  if (is_hir_item)
+    {
+      if (!lookup->has_subsititions_defined ())
+	return CompileItem::compile (resolved_item, ctx, nullptr, true,
+				     expr_locus);
+      else
+	return CompileItem::compile (resolved_item, ctx, lookup, true,
+				     expr_locus);
+    }
+  else if (is_hir_extern_item)
+    {
+      if (!lookup->has_subsititions_defined ())
+	return CompileExternItem::compile (resolved_extern_item, ctx, nullptr,
+					   true, expr_locus);
+      else
+	return CompileExternItem::compile (resolved_extern_item, ctx, lookup,
+					   true, expr_locus);
+    }
+  else
+    {
+      HirId parent_impl_id = UNKNOWN_HIRID;
+      HIR::ImplItem *resolved_item
+	= ctx->get_mappings ()->lookup_hir_implitem (ref, &parent_impl_id);
+      bool is_impl_item = resolved_item != nullptr;
+      if (is_impl_item)
+	{
+	  rust_assert (parent_impl_id != UNKNOWN_HIRID);
+	  HIR::Item *impl_ref
+	    = ctx->get_mappings ()->lookup_hir_item (parent_impl_id);
+	  rust_assert (impl_ref != nullptr);
+	  HIR::ImplBlock *impl = static_cast<HIR::ImplBlock *> (impl_ref);
+
+	  TyTy::BaseType *self = nullptr;
+	  bool ok = ctx->get_tyctx ()->lookup_type (
+	    impl->get_type ()->get_mappings ().get_hirid (), &self);
+	  rust_assert (ok);
+
+	  if (!lookup->has_subsititions_defined ())
+	    return CompileInherentImplItem::Compile (resolved_item, ctx,
+						     nullptr, true, expr_locus);
+	  else
+	    return CompileInherentImplItem::Compile (resolved_item, ctx, lookup,
+						     true, expr_locus);
+	}
+      else
+	{
+	  // it might be resolved to a trait item
+	  HIR::TraitItem *trait_item
+	    = ctx->get_mappings ()->lookup_hir_trait_item (ref);
+	  HIR::Trait *trait = ctx->get_mappings ()->lookup_trait_item_mapping (
+	    trait_item->get_mappings ().get_hirid ());
+
+	  Resolver::TraitReference *trait_ref
+	    = &Resolver::TraitReference::error_node ();
+	  bool ok = ctx->get_tyctx ()->lookup_trait_reference (
+	    trait->get_mappings ().get_defid (), &trait_ref);
+	  rust_assert (ok);
+
+	  TyTy::BaseType *receiver = nullptr;
+	  ok = ctx->get_tyctx ()->lookup_receiver (mappings.get_hirid (),
+						   &receiver);
+	  rust_assert (ok);
+
+	  if (receiver->get_kind () == TyTy::TypeKind::PARAM)
+	    {
+	      TyTy::ParamType *p = static_cast<TyTy::ParamType *> (receiver);
+	      receiver = p->resolve ();
+	    }
+
+	  // the type resolver can only resolve type bounds to their trait
+	  // item so its up to us to figure out if this path should resolve
+	  // to an trait-impl-block-item or if it can be defaulted to the
+	  // trait-impl-item's definition
+	  std::vector<Resolver::PathProbeCandidate> candidates
+	    = Resolver::PathProbeImplTrait::Probe (receiver, final_segment,
+						   trait_ref);
+	  if (candidates.size () == 0)
+	    {
+	      // this means we are defaulting back to the trait_item if
+	      // possible
+	      Resolver::TraitItemReference *trait_item_ref = nullptr;
+	      bool ok = trait_ref->lookup_hir_trait_item (*trait_item,
+							  &trait_item_ref);
+	      rust_assert (ok);				    // found
+	      rust_assert (trait_item_ref->is_optional ()); // has definition
+
+	      return CompileTraitItem::Compile (
+		trait_item_ref->get_hir_trait_item (), ctx, lookup, true,
+		expr_locus);
+	    }
+	  else
+	    {
+	      Resolver::PathProbeCandidate &candidate = candidates.at (0);
+	      rust_assert (candidate.is_impl_candidate ());
+
+	      HIR::ImplBlock *impl = candidate.item.impl.parent;
+	      HIR::ImplItem *impl_item = candidate.item.impl.impl_item;
+
+	      TyTy::BaseType *self = nullptr;
+	      bool ok = ctx->get_tyctx ()->lookup_type (
+		impl->get_type ()->get_mappings ().get_hirid (), &self);
+	      rust_assert (ok);
+
+	      if (!lookup->has_subsititions_defined ())
+		return CompileInherentImplItem::Compile (impl_item, ctx,
+							 nullptr, true,
+							 expr_locus);
+	      else
+		return CompileInherentImplItem::Compile (impl_item, ctx, lookup,
+							 true, expr_locus);
+
+	      lookup->set_ty_ref (impl_item->get_impl_mappings ().get_hirid ());
+	    }
+	}
+    }
+
+  return error_mark_node;
+}
+
+} // namespace Compile
+} // namespace Rust
diff --git a/gcc/rust/backend/rust-compile-resolve-path.h b/gcc/rust/backend/rust-compile-resolve-path.h
new file mode 100644
index 00000000000..f0360bdc739
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-resolve-path.h
@@ -0,0 +1,73 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_COMPILE_RESOLVE_PATH
+#define RUST_COMPILE_RESOLVE_PATH
+
+#include "rust-compile-base.h"
+
+namespace Rust {
+namespace Compile {
+
+class ResolvePathRef : public HIRCompileBase, public HIR::HIRPatternVisitor
+{
+public:
+  static tree Compile (HIR::QualifiedPathInExpression &expr, Context *ctx)
+  {
+    ResolvePathRef resolver (ctx);
+    expr.accept_vis (resolver);
+    return resolver.resolved;
+  }
+
+  static tree Compile (HIR::PathInExpression &expr, Context *ctx)
+  {
+    ResolvePathRef resolver (ctx);
+    expr.accept_vis (resolver);
+    return resolver.resolved;
+  }
+
+  void visit (HIR::PathInExpression &expr) override;
+  void visit (HIR::QualifiedPathInExpression &expr) override;
+
+  // Empty visit for unused Pattern HIR nodes.
+  void visit (HIR::GroupedPattern &) override {}
+  void visit (HIR::IdentifierPattern &) override {}
+  void visit (HIR::LiteralPattern &) override {}
+  void visit (HIR::RangePattern &) override {}
+  void visit (HIR::ReferencePattern &) override {}
+  void visit (HIR::SlicePattern &) override {}
+  void visit (HIR::StructPattern &) override {}
+  void visit (HIR::TuplePattern &) override {}
+  void visit (HIR::TupleStructPattern &) override {}
+  void visit (HIR::WildcardPattern &) override {}
+
+  ResolvePathRef (Context *ctx)
+    : HIRCompileBase (ctx), resolved (error_mark_node)
+  {}
+
+  tree resolve (const HIR::PathIdentSegment &final_segment,
+		const Analysis::NodeMapping &mappings, Location locus,
+		bool is_qualified_path);
+
+  tree resolved;
+};
+
+} // namespace Compile
+} // namespace Rust
+
+#endif // RUST_COMPILE_RESOLVE_PATH
diff --git a/gcc/rust/backend/rust-compile-stmt.cc b/gcc/rust/backend/rust-compile-stmt.cc
new file mode 100644
index 00000000000..bfb25f12980
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-stmt.cc
@@ -0,0 +1,115 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-compile-stmt.h"
+#include "rust-compile-expr.h"
+
+namespace Rust {
+namespace Compile {
+
+CompileStmt::CompileStmt (Context *ctx)
+  : HIRCompileBase (ctx), translated (nullptr)
+{}
+
+tree
+CompileStmt::Compile (HIR::Stmt *stmt, Context *ctx)
+{
+  CompileStmt compiler (ctx);
+  stmt->accept_vis (compiler);
+  return compiler.translated;
+}
+
+void
+CompileStmt::visit (HIR::ExprStmtWithBlock &stmt)
+{
+  translated = CompileExpr::Compile (stmt.get_expr (), ctx);
+}
+
+void
+CompileStmt::visit (HIR::ExprStmtWithoutBlock &stmt)
+{
+  translated = CompileExpr::Compile (stmt.get_expr (), ctx);
+}
+
+void
+CompileStmt::visit (HIR::LetStmt &stmt)
+{
+  // nothing to do
+  if (!stmt.has_init_expr ())
+    return;
+
+  const HIR::Pattern &stmt_pattern = *stmt.get_pattern ();
+  HirId stmt_id = stmt_pattern.get_pattern_mappings ().get_hirid ();
+
+  TyTy::BaseType *ty = nullptr;
+  if (!ctx->get_tyctx ()->lookup_type (stmt_id, &ty))
+    {
+      // FIXME this should be an assertion instead
+      rust_fatal_error (stmt.get_locus (),
+			"failed to lookup variable declaration type");
+      return;
+    }
+
+  Bvariable *var = nullptr;
+  if (!ctx->lookup_var_decl (stmt_id, &var))
+    {
+      // FIXME this should be an assertion instead and use error mark node
+      rust_fatal_error (stmt.get_locus (),
+			"failed to lookup compiled variable declaration");
+      return;
+    }
+
+  tree init = CompileExpr::Compile (stmt.get_init_expr (), ctx);
+  // FIXME use error_mark_node, check that CompileExpr returns error_mark_node
+  // on failure and make this an assertion
+  if (init == nullptr)
+    return;
+
+  TyTy::BaseType *actual = nullptr;
+  bool ok = ctx->get_tyctx ()->lookup_type (
+    stmt.get_init_expr ()->get_mappings ().get_hirid (), &actual);
+  rust_assert (ok);
+  tree stmt_type = TyTyResolveCompile::compile (ctx, ty);
+
+  Location lvalue_locus = stmt.get_pattern ()->get_locus ();
+  Location rvalue_locus = stmt.get_init_expr ()->get_locus ();
+  TyTy::BaseType *expected = ty;
+  init = coercion_site (stmt.get_mappings ().get_hirid (), init, actual,
+			expected, lvalue_locus, rvalue_locus);
+
+  auto fnctx = ctx->peek_fn ();
+  if (ty->is_unit ())
+    {
+      ctx->add_statement (init);
+
+      auto unit_type_init_expr
+	= ctx->get_backend ()->constructor_expression (stmt_type, false, {}, -1,
+						       rvalue_locus);
+      auto s = ctx->get_backend ()->init_statement (fnctx.fndecl, var,
+						    unit_type_init_expr);
+      ctx->add_statement (s);
+    }
+  else
+    {
+      auto s = ctx->get_backend ()->init_statement (fnctx.fndecl, var, init);
+      ctx->add_statement (s);
+    }
+}
+
+} // namespace Compile
+} // namespace Rust
diff --git a/gcc/rust/backend/rust-compile-stmt.h b/gcc/rust/backend/rust-compile-stmt.h
new file mode 100644
index 00000000000..a0ec8b26667
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-stmt.h
@@ -0,0 +1,69 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_COMPILE_STMT
+#define RUST_COMPILE_STMT
+
+#include "rust-compile-base.h"
+
+namespace Rust {
+namespace Compile {
+
+class CompileStmt : private HIRCompileBase, protected HIR::HIRStmtVisitor
+{
+public:
+  static tree Compile (HIR::Stmt *stmt, Context *ctx);
+
+  void visit (HIR::ExprStmtWithBlock &stmt) override;
+  void visit (HIR::ExprStmtWithoutBlock &stmt) override;
+  void visit (HIR::LetStmt &stmt) override;
+
+  // Empty visit for unused Stmt HIR nodes.
+  void visit (HIR::TupleStruct &) override {}
+  void visit (HIR::EnumItem &) override {}
+  void visit (HIR::EnumItemTuple &) override {}
+  void visit (HIR::EnumItemStruct &) override {}
+  void visit (HIR::EnumItemDiscriminant &) override {}
+  void visit (HIR::TypePathSegmentFunction &) override {}
+  void visit (HIR::TypePath &) override {}
+  void visit (HIR::QualifiedPathInType &) override {}
+  void visit (HIR::Module &) override {}
+  void visit (HIR::ExternCrate &) override {}
+  void visit (HIR::UseDeclaration &) override {}
+  void visit (HIR::Function &) override {}
+  void visit (HIR::TypeAlias &) override {}
+  void visit (HIR::StructStruct &) override {}
+  void visit (HIR::Enum &) override {}
+  void visit (HIR::Union &) override {}
+  void visit (HIR::ConstantItem &) override {}
+  void visit (HIR::StaticItem &) override {}
+  void visit (HIR::Trait &) override {}
+  void visit (HIR::ImplBlock &) override {}
+  void visit (HIR::ExternBlock &) override {}
+  void visit (HIR::EmptyStmt &) override {}
+
+private:
+  CompileStmt (Context *ctx);
+
+  tree translated;
+};
+
+} // namespace Compile
+} // namespace Rust
+
+#endif // RUST_COMPILE_STMT
diff --git a/gcc/rust/backend/rust-compile-struct-field-expr.cc b/gcc/rust/backend/rust-compile-struct-field-expr.cc
new file mode 100644
index 00000000000..c9a2811f611
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-struct-field-expr.cc
@@ -0,0 +1,81 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-compile-struct-field-expr.h"
+#include "rust-compile-expr.h"
+
+namespace Rust {
+namespace Compile {
+
+CompileStructExprField::CompileStructExprField (Context *ctx)
+  : HIRCompileBase (ctx), translated (error_mark_node)
+{}
+
+tree
+CompileStructExprField::Compile (HIR::StructExprField *field, Context *ctx)
+{
+  CompileStructExprField compiler (ctx);
+  switch (field->get_kind ())
+    {
+    case HIR::StructExprField::StructExprFieldKind::IDENTIFIER:
+      compiler.visit (static_cast<HIR::StructExprFieldIdentifier &> (*field));
+      break;
+
+    case HIR::StructExprField::StructExprFieldKind::IDENTIFIER_VALUE:
+      compiler.visit (
+	static_cast<HIR::StructExprFieldIdentifierValue &> (*field));
+      break;
+
+    case HIR::StructExprField::StructExprFieldKind::INDEX_VALUE:
+      compiler.visit (static_cast<HIR::StructExprFieldIndexValue &> (*field));
+      break;
+    }
+  return compiler.translated;
+}
+
+void
+CompileStructExprField::visit (HIR::StructExprFieldIdentifierValue &field)
+{
+  translated = CompileExpr::Compile (field.get_value (), ctx);
+}
+
+void
+CompileStructExprField::visit (HIR::StructExprFieldIndexValue &field)
+{
+  translated = CompileExpr::Compile (field.get_value (), ctx);
+}
+
+void
+CompileStructExprField::visit (HIR::StructExprFieldIdentifier &field)
+{
+  // we can make the field look like a path expr to take advantage of existing
+  // code
+
+  Analysis::NodeMapping mappings_copy1 = field.get_mappings ();
+  Analysis::NodeMapping mappings_copy2 = field.get_mappings ();
+
+  HIR::PathIdentSegment ident_seg (field.get_field_name ());
+  HIR::PathExprSegment seg (mappings_copy1, ident_seg, field.get_locus (),
+			    HIR::GenericArgs::create_empty ());
+  HIR::PathInExpression expr (mappings_copy2, {seg}, field.get_locus (), false,
+			      {});
+  translated = CompileExpr::Compile (&expr, ctx);
+}
+
+} // namespace Compile
+} // namespace Rust
diff --git a/gcc/rust/backend/rust-compile-struct-field-expr.h b/gcc/rust/backend/rust-compile-struct-field-expr.h
new file mode 100644
index 00000000000..bc5da080dfe
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-struct-field-expr.h
@@ -0,0 +1,46 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_COMPILE_STRUCT_FIELD_EXPR
+#define RUST_COMPILE_STRUCT_FIELD_EXPR
+
+#include "rust-compile-base.h"
+
+namespace Rust {
+namespace Compile {
+
+class CompileStructExprField : private HIRCompileBase
+{
+public:
+  static tree Compile (HIR::StructExprField *field, Context *ctx);
+
+protected:
+  void visit (HIR::StructExprFieldIdentifierValue &field);
+  void visit (HIR::StructExprFieldIndexValue &field);
+  void visit (HIR::StructExprFieldIdentifier &field);
+
+private:
+  CompileStructExprField (Context *ctx);
+
+  tree translated;
+};
+
+} // namespace Compile
+} // namespace Rust
+
+#endif // RUST_COMPILE_STRUCT_FIELD_EXPR
diff --git a/gcc/rust/backend/rust-compile-type.cc b/gcc/rust/backend/rust-compile-type.cc
new file mode 100644
index 00000000000..eced909673e
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-type.cc
@@ -0,0 +1,713 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-compile-type.h"
+#include "rust-compile-expr.h"
+#include "rust-constexpr.h"
+
+#include "tree.h"
+
+namespace Rust {
+namespace Compile {
+
+static const std::string RUST_ENUM_DISR_FIELD_NAME = "RUST$ENUM$DISR";
+
+TyTyResolveCompile::TyTyResolveCompile (Context *ctx, bool trait_object_mode)
+  : ctx (ctx), trait_object_mode (trait_object_mode),
+    translated (error_mark_node), recurisve_ops (0)
+{}
+
+tree
+TyTyResolveCompile::compile (Context *ctx, const TyTy::BaseType *ty,
+			     bool trait_object_mode)
+{
+  TyTyResolveCompile compiler (ctx, trait_object_mode);
+  ty->accept_vis (compiler);
+
+  if (compiler.translated != error_mark_node
+      && TYPE_NAME (compiler.translated) != NULL)
+    {
+      // canonicalize the type
+      compiler.translated = ctx->insert_compiled_type (compiler.translated);
+    }
+
+  return compiler.translated;
+}
+
+// see: gcc/c/c-decl.cc:8230-8241
+// https://github.com/Rust-GCC/gccrs/blob/0024bc2f028369b871a65ceb11b2fddfb0f9c3aa/gcc/c/c-decl.c#L8229-L8241
+tree
+TyTyResolveCompile::get_implicit_enumeral_node_type (Context *ctx)
+{
+  // static tree enum_node = NULL_TREE;
+  // if (enum_node == NULL_TREE)
+  //   {
+  //     enum_node = make_node (ENUMERAL_TYPE);
+  //     SET_TYPE_MODE (enum_node, TYPE_MODE (unsigned_type_node));
+  //     SET_TYPE_ALIGN (enum_node, TYPE_ALIGN (unsigned_type_node));
+  //     TYPE_USER_ALIGN (enum_node) = 0;
+  //     TYPE_UNSIGNED (enum_node) = 1;
+  //     TYPE_PRECISION (enum_node) = TYPE_PRECISION (unsigned_type_node);
+  //     TYPE_MIN_VALUE (enum_node) = TYPE_MIN_VALUE (unsigned_type_node);
+  //     TYPE_MAX_VALUE (enum_node) = TYPE_MAX_VALUE (unsigned_type_node);
+
+  //     // tree identifier = ctx->get_backend ()->get_identifier_node
+  //     // ("enumeral"); tree enum_decl
+  //     //   = build_decl (BUILTINS_LOCATION, TYPE_DECL, identifier,
+  //     enum_node);
+  //     // TYPE_NAME (enum_node) = enum_decl;
+  //   }
+  // return enum_node;
+
+  static tree enum_node = NULL_TREE;
+  if (enum_node == NULL_TREE)
+    {
+      enum_node = ctx->get_backend ()->named_type (
+	"enumeral", ctx->get_backend ()->integer_type (false, 64),
+	Linemap::predeclared_location ());
+    }
+  return enum_node;
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::ErrorType &)
+{
+  translated = error_mark_node;
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::InferType &)
+{
+  translated = error_mark_node;
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::ClosureType &)
+{
+  gcc_unreachable ();
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::ProjectionType &type)
+{
+  type.get ()->accept_vis (*this);
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::PlaceholderType &type)
+{
+  type.resolve ()->accept_vis (*this);
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::ParamType &param)
+{
+  if (recurisve_ops++ >= rust_max_recursion_depth)
+    {
+      rust_error_at (Location (),
+		     "%<recursion depth%> count exceeds limit of %i (use "
+		     "%<frust-max-recursion-depth=%> to increase the limit)",
+		     rust_max_recursion_depth);
+      translated = error_mark_node;
+      return;
+    }
+
+  param.resolve ()->accept_vis (*this);
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::FnType &type)
+{
+  Backend::typed_identifier receiver;
+  std::vector<Backend::typed_identifier> parameters;
+  std::vector<Backend::typed_identifier> results;
+
+  if (!type.get_return_type ()->is_unit ())
+    {
+      auto hir_type = type.get_return_type ();
+      auto ret = TyTyResolveCompile::compile (ctx, hir_type, trait_object_mode);
+      results.push_back (Backend::typed_identifier (
+	"_", ret,
+	ctx->get_mappings ()->lookup_location (hir_type->get_ref ())));
+    }
+
+  for (auto &param_pair : type.get_params ())
+    {
+      auto param_tyty = param_pair.second;
+      auto compiled_param_type
+	= TyTyResolveCompile::compile (ctx, param_tyty, trait_object_mode);
+
+      auto compiled_param = Backend::typed_identifier (
+	param_pair.first->as_string (), compiled_param_type,
+	ctx->get_mappings ()->lookup_location (param_tyty->get_ref ()));
+
+      parameters.push_back (compiled_param);
+    }
+
+  if (!type.is_varadic ())
+    translated
+      = ctx->get_backend ()->function_type (receiver, parameters, results, NULL,
+					    type.get_ident ().locus);
+  else
+    translated
+      = ctx->get_backend ()->function_type_varadic (receiver, parameters,
+						    results, NULL,
+						    type.get_ident ().locus);
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::FnPtr &type)
+{
+  tree result_type = TyTyResolveCompile::compile (ctx, type.get_return_type ());
+
+  std::vector<tree> parameters;
+
+  auto &params = type.get_params ();
+  for (auto &p : params)
+    {
+      tree pty = TyTyResolveCompile::compile (ctx, p.get_tyty ());
+      parameters.push_back (pty);
+    }
+
+  translated = ctx->get_backend ()->function_ptr_type (result_type, parameters,
+						       type.get_ident ().locus);
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::ADTType &type)
+{
+  tree type_record = error_mark_node;
+  if (!type.is_enum ())
+    {
+      rust_assert (type.number_of_variants () == 1);
+
+      TyTy::VariantDef &variant = *type.get_variants ().at (0);
+      std::vector<Backend::typed_identifier> fields;
+      for (size_t i = 0; i < variant.num_fields (); i++)
+	{
+	  const TyTy::StructFieldType *field = variant.get_field_at_index (i);
+	  tree compiled_field_ty
+	    = TyTyResolveCompile::compile (ctx, field->get_field_type ());
+
+	  Backend::typed_identifier f (field->get_name (), compiled_field_ty,
+				       ctx->get_mappings ()->lookup_location (
+					 type.get_ty_ref ()));
+	  fields.push_back (std::move (f));
+	}
+
+      type_record = type.is_union ()
+		      ? ctx->get_backend ()->union_type (fields)
+		      : ctx->get_backend ()->struct_type (fields);
+    }
+  else
+    {
+      // see:
+      // https://github.com/bminor/binutils-gdb/blob/527b8861cd472385fa9160a91dd6d65a25c41987/gdb/dwarf2/read.c#L9010-L9241
+      //
+      // enums are actually a big union so for example the rust enum:
+      //
+      // enum AnEnum {
+      //   A,
+      //   B,
+      //   C (char),
+      //   D { x: i64, y: i64 },
+      // }
+      //
+      // we actually turn this into
+      //
+      // union {
+      //   struct A { int RUST$ENUM$DISR; }; <- this is a data-less variant
+      //   struct B { int RUST$ENUM$DISR; }; <- this is a data-less variant
+      //   struct C { int RUST$ENUM$DISR; char __0; };
+      //   struct D { int RUST$ENUM$DISR; i64 x; i64 y; };
+      // }
+      //
+      // Ada, qual_union_types might still work for this but I am not 100% sure.
+      // I ran into some issues lets reuse our normal union and ask Ada people
+      // about it.
+
+      std::vector<tree> variant_records;
+      for (auto &variant : type.get_variants ())
+	{
+	  std::vector<Backend::typed_identifier> fields;
+
+	  // add in the qualifier field for the variant
+	  tree enumeral_type
+	    = TyTyResolveCompile::get_implicit_enumeral_node_type (ctx);
+	  Backend::typed_identifier f (RUST_ENUM_DISR_FIELD_NAME, enumeral_type,
+				       ctx->get_mappings ()->lookup_location (
+					 variant->get_id ()));
+	  fields.push_back (std::move (f));
+
+	  // compile the rest of the fields
+	  for (size_t i = 0; i < variant->num_fields (); i++)
+	    {
+	      const TyTy::StructFieldType *field
+		= variant->get_field_at_index (i);
+	      tree compiled_field_ty
+		= TyTyResolveCompile::compile (ctx, field->get_field_type ());
+
+	      std::string field_name = field->get_name ();
+	      if (variant->get_variant_type ()
+		  == TyTy::VariantDef::VariantType::TUPLE)
+		field_name = "__" + field->get_name ();
+
+	      Backend::typed_identifier f (
+		field_name, compiled_field_ty,
+		ctx->get_mappings ()->lookup_location (type.get_ty_ref ()));
+	      fields.push_back (std::move (f));
+	    }
+
+	  tree variant_record = ctx->get_backend ()->struct_type (fields);
+	  tree named_variant_record = ctx->get_backend ()->named_type (
+	    variant->get_ident ().path.get (), variant_record,
+	    variant->get_ident ().locus);
+
+	  // set the qualifier to be a builtin
+	  DECL_ARTIFICIAL (TYPE_FIELDS (variant_record)) = 1;
+
+	  // add them to the list
+	  variant_records.push_back (named_variant_record);
+	}
+
+      // now we need to make the actual union, but first we need to make
+      // named_type TYPE_DECL's out of the variants
+
+      size_t i = 0;
+      std::vector<Backend::typed_identifier> enum_fields;
+      for (auto &variant_record : variant_records)
+	{
+	  TyTy::VariantDef *variant = type.get_variants ().at (i++);
+	  std::string implicit_variant_name = variant->get_identifier ();
+
+	  Backend::typed_identifier f (implicit_variant_name, variant_record,
+				       ctx->get_mappings ()->lookup_location (
+					 type.get_ty_ref ()));
+	  enum_fields.push_back (std::move (f));
+	}
+
+      // finally make the union or the enum
+      type_record = ctx->get_backend ()->union_type (enum_fields);
+    }
+
+  // Handle repr options
+  // TODO: "packed" should only narrow type alignment and "align" should only
+  // widen it. Do we need to check and enforce this here, or is it taken care of
+  // later on in the gcc middle-end?
+  TyTy::ADTType::ReprOptions repr = type.get_repr_options ();
+  if (repr.pack)
+    {
+      TYPE_PACKED (type_record) = 1;
+      if (repr.pack > 1)
+	{
+	  SET_TYPE_ALIGN (type_record, repr.pack * 8);
+	  TYPE_USER_ALIGN (type_record) = 1;
+	}
+    }
+  else if (repr.align)
+    {
+      SET_TYPE_ALIGN (type_record, repr.align * 8);
+      TYPE_USER_ALIGN (type_record) = 1;
+    }
+
+  std::string named_struct_str
+    = type.get_ident ().path.get () + type.subst_as_string ();
+  translated = ctx->get_backend ()->named_type (named_struct_str, type_record,
+						type.get_ident ().locus);
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::TupleType &type)
+{
+  if (type.num_fields () == 0)
+    {
+      translated = ctx->get_backend ()->unit_type ();
+      return;
+    }
+
+  // create implicit struct
+  std::vector<Backend::typed_identifier> fields;
+  for (size_t i = 0; i < type.num_fields (); i++)
+    {
+      TyTy::BaseType *field = type.get_field (i);
+      tree compiled_field_ty = TyTyResolveCompile::compile (ctx, field);
+
+      // rustc uses the convention __N, where N is an integer, to
+      // name the fields of a tuple.  We follow this as well,
+      // because this is used by GDB.  One further reason to prefer
+      // this, rather than simply emitting the integer, is that this
+      // approach makes it simpler to use a C-only debugger, or
+      // GDB's C mode, when debugging Rust.
+      Backend::typed_identifier f ("__" + std::to_string (i), compiled_field_ty,
+				   ctx->get_mappings ()->lookup_location (
+				     type.get_ty_ref ()));
+      fields.push_back (std::move (f));
+    }
+
+  tree struct_type_record = ctx->get_backend ()->struct_type (fields);
+  translated
+    = ctx->get_backend ()->named_type (type.as_string (), struct_type_record,
+				       type.get_ident ().locus);
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::ArrayType &type)
+{
+  tree element_type
+    = TyTyResolveCompile::compile (ctx, type.get_element_type ());
+  tree capacity_expr = CompileExpr::Compile (&type.get_capacity_expr (), ctx);
+  tree folded_capacity_expr = fold_expr (capacity_expr);
+
+  translated
+    = ctx->get_backend ()->array_type (element_type, folded_capacity_expr);
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::SliceType &type)
+{
+  tree type_record = create_slice_type_record (type);
+
+  std::string named_struct_str
+    = std::string ("[") + type.get_element_type ()->get_name () + "]";
+  translated = ctx->get_backend ()->named_type (named_struct_str, type_record,
+						type.get_ident ().locus);
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::BoolType &type)
+{
+  translated
+    = ctx->get_backend ()->named_type ("bool",
+				       ctx->get_backend ()->bool_type (),
+				       Linemap::predeclared_location ());
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::IntType &type)
+{
+  switch (type.get_int_kind ())
+    {
+    case TyTy::IntType::I8:
+      translated = ctx->get_backend ()->named_type (
+	"i8", ctx->get_backend ()->integer_type (false, 8),
+	Linemap::predeclared_location ());
+      return;
+
+    case TyTy::IntType::I16:
+      translated = ctx->get_backend ()->named_type (
+	"i16", ctx->get_backend ()->integer_type (false, 16),
+	Linemap::predeclared_location ());
+      return;
+
+    case TyTy::IntType::I32:
+      translated = ctx->get_backend ()->named_type (
+	"i32", ctx->get_backend ()->integer_type (false, 32),
+	Linemap::predeclared_location ());
+      return;
+
+    case TyTy::IntType::I64:
+      translated = ctx->get_backend ()->named_type (
+	"i64", ctx->get_backend ()->integer_type (false, 64),
+	Linemap::predeclared_location ());
+      return;
+
+    case TyTy::IntType::I128:
+      translated = ctx->get_backend ()->named_type (
+	"i128", ctx->get_backend ()->integer_type (false, 128),
+	Linemap::predeclared_location ());
+      return;
+    }
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::UintType &type)
+{
+  switch (type.get_uint_kind ())
+    {
+    case TyTy::UintType::U8:
+      translated = ctx->get_backend ()->named_type (
+	"u8", ctx->get_backend ()->integer_type (true, 8),
+	Linemap::predeclared_location ());
+      return;
+
+    case TyTy::UintType::U16:
+      translated = ctx->get_backend ()->named_type (
+	"u16", ctx->get_backend ()->integer_type (true, 16),
+	Linemap::predeclared_location ());
+      return;
+
+    case TyTy::UintType::U32:
+      translated = ctx->get_backend ()->named_type (
+	"u32", ctx->get_backend ()->integer_type (true, 32),
+	Linemap::predeclared_location ());
+      return;
+
+    case TyTy::UintType::U64:
+      translated = ctx->get_backend ()->named_type (
+	"u64", ctx->get_backend ()->integer_type (true, 64),
+	Linemap::predeclared_location ());
+      return;
+
+    case TyTy::UintType::U128:
+      translated = ctx->get_backend ()->named_type (
+	"u128", ctx->get_backend ()->integer_type (true, 128),
+	Linemap::predeclared_location ());
+      return;
+    }
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::FloatType &type)
+{
+  switch (type.get_float_kind ())
+    {
+    case TyTy::FloatType::F32:
+      translated
+	= ctx->get_backend ()->named_type ("f32",
+					   ctx->get_backend ()->float_type (32),
+					   Linemap::predeclared_location ());
+      return;
+
+    case TyTy::FloatType::F64:
+      translated
+	= ctx->get_backend ()->named_type ("f64",
+					   ctx->get_backend ()->float_type (64),
+					   Linemap::predeclared_location ());
+      return;
+    }
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::USizeType &type)
+{
+  translated = ctx->get_backend ()->named_type (
+    "usize",
+    ctx->get_backend ()->integer_type (
+      true, ctx->get_backend ()->get_pointer_size ()),
+    Linemap::predeclared_location ());
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::ISizeType &type)
+{
+  translated = ctx->get_backend ()->named_type (
+    "isize",
+    ctx->get_backend ()->integer_type (
+      false, ctx->get_backend ()->get_pointer_size ()),
+    Linemap::predeclared_location ());
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::CharType &type)
+{
+  translated
+    = ctx->get_backend ()->named_type ("char",
+				       ctx->get_backend ()->wchar_type (),
+				       Linemap::predeclared_location ());
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::ReferenceType &type)
+{
+  const TyTy::SliceType *slice = nullptr;
+  const TyTy::StrType *str = nullptr;
+  if (type.is_dyn_slice_type (&slice))
+    {
+      tree type_record = create_slice_type_record (*slice);
+      std::string dyn_slice_type_str
+	= std::string (type.is_mutable () ? "&mut " : "&") + "["
+	  + slice->get_element_type ()->get_name () + "]";
+
+      translated
+	= ctx->get_backend ()->named_type (dyn_slice_type_str, type_record,
+					   slice->get_locus ());
+
+      return;
+    }
+  else if (type.is_dyn_str_type (&str))
+    {
+      tree type_record = create_str_type_record (*str);
+      std::string dyn_str_type_str
+	= std::string (type.is_mutable () ? "&mut " : "&") + "str";
+
+      translated
+	= ctx->get_backend ()->named_type (dyn_str_type_str, type_record,
+					   str->get_locus ());
+
+      return;
+    }
+
+  tree base_compiled_type
+    = TyTyResolveCompile::compile (ctx, type.get_base (), trait_object_mode);
+  if (type.is_mutable ())
+    {
+      translated = ctx->get_backend ()->reference_type (base_compiled_type);
+    }
+  else
+    {
+      auto base = ctx->get_backend ()->immutable_type (base_compiled_type);
+      translated = ctx->get_backend ()->reference_type (base);
+    }
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::PointerType &type)
+{
+  const TyTy::SliceType *slice = nullptr;
+  const TyTy::StrType *str = nullptr;
+  if (type.is_dyn_slice_type (&slice))
+    {
+      tree type_record = create_slice_type_record (*slice);
+      std::string dyn_slice_type_str
+	= std::string (type.is_mutable () ? "*mut " : "*const ") + "["
+	  + slice->get_element_type ()->get_name () + "]";
+
+      translated
+	= ctx->get_backend ()->named_type (dyn_slice_type_str, type_record,
+					   slice->get_locus ());
+
+      return;
+    }
+  else if (type.is_dyn_str_type (&str))
+    {
+      tree type_record = create_str_type_record (*str);
+      std::string dyn_str_type_str
+	= std::string (type.is_mutable () ? "*mut " : "*const ") + "str";
+
+      translated
+	= ctx->get_backend ()->named_type (dyn_str_type_str, type_record,
+					   str->get_locus ());
+
+      return;
+    }
+
+  tree base_compiled_type
+    = TyTyResolveCompile::compile (ctx, type.get_base (), trait_object_mode);
+  if (type.is_mutable ())
+    {
+      translated = ctx->get_backend ()->pointer_type (base_compiled_type);
+    }
+  else
+    {
+      auto base = ctx->get_backend ()->immutable_type (base_compiled_type);
+      translated = ctx->get_backend ()->pointer_type (base);
+    }
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::StrType &type)
+{
+  tree raw_str = create_str_type_record (type);
+  translated
+    = ctx->get_backend ()->named_type ("str", raw_str,
+				       Linemap::predeclared_location ());
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::NeverType &)
+{
+  translated = ctx->get_backend ()->unit_type ();
+}
+
+void
+TyTyResolveCompile::visit (const TyTy::DynamicObjectType &type)
+{
+  if (trait_object_mode)
+    {
+      translated = ctx->get_backend ()->integer_type (
+	true, ctx->get_backend ()->get_pointer_size ());
+      return;
+    }
+
+  // create implicit struct
+  auto items = type.get_object_items ();
+  std::vector<Backend::typed_identifier> fields;
+
+  tree uint = ctx->get_backend ()->integer_type (
+    true, ctx->get_backend ()->get_pointer_size ());
+  tree uintptr_ty = build_pointer_type (uint);
+
+  Backend::typed_identifier f ("pointer", uintptr_ty,
+			       ctx->get_mappings ()->lookup_location (
+				 type.get_ty_ref ()));
+  fields.push_back (std::move (f));
+
+  tree vtable_size = build_int_cst (size_type_node, items.size ());
+  tree vtable_type = ctx->get_backend ()->array_type (uintptr_ty, vtable_size);
+  Backend::typed_identifier vtf ("vtable", vtable_type,
+				 ctx->get_mappings ()->lookup_location (
+				   type.get_ty_ref ()));
+  fields.push_back (std::move (vtf));
+
+  tree type_record = ctx->get_backend ()->struct_type (fields);
+  translated = ctx->get_backend ()->named_type (type.get_name (), type_record,
+						type.get_ident ().locus);
+}
+
+tree
+TyTyResolveCompile::create_slice_type_record (const TyTy::SliceType &type)
+{
+  // lookup usize
+  TyTy::BaseType *usize = nullptr;
+  bool ok = ctx->get_tyctx ()->lookup_builtin ("usize", &usize);
+  rust_assert (ok);
+
+  tree element_type
+    = TyTyResolveCompile::compile (ctx, type.get_element_type ());
+  tree data_field_ty = build_pointer_type (element_type);
+  Backend::typed_identifier data_field ("data", data_field_ty,
+					type.get_locus ());
+
+  tree len_field_ty = TyTyResolveCompile::compile (ctx, usize);
+  Backend::typed_identifier len_field ("len", len_field_ty, type.get_locus ());
+
+  tree record = ctx->get_backend ()->struct_type ({data_field, len_field});
+  SLICE_FLAG (record) = 1;
+  TYPE_MAIN_VARIANT (record) = ctx->insert_main_variant (record);
+
+  return record;
+}
+
+tree
+TyTyResolveCompile::create_str_type_record (const TyTy::StrType &type)
+{
+  // lookup usize
+  TyTy::BaseType *usize = nullptr;
+  bool ok = ctx->get_tyctx ()->lookup_builtin ("usize", &usize);
+  rust_assert (ok);
+
+  tree char_ptr = build_pointer_type (char_type_node);
+  tree const_char_type = build_qualified_type (char_ptr, TYPE_QUAL_CONST);
+
+  tree element_type = const_char_type;
+  tree data_field_ty = build_pointer_type (element_type);
+  Backend::typed_identifier data_field ("data", data_field_ty,
+					type.get_locus ());
+
+  tree len_field_ty = TyTyResolveCompile::compile (ctx, usize);
+  Backend::typed_identifier len_field ("len", len_field_ty, type.get_locus ());
+
+  tree record = ctx->get_backend ()->struct_type ({data_field, len_field});
+  SLICE_FLAG (record) = 1;
+  TYPE_MAIN_VARIANT (record) = ctx->insert_main_variant (record);
+
+  return record;
+}
+
+} // namespace Compile
+} // namespace Rust
diff --git a/gcc/rust/backend/rust-compile-type.h b/gcc/rust/backend/rust-compile-type.h
new file mode 100644
index 00000000000..b52fd71bf6b
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-type.h
@@ -0,0 +1,79 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_COMPILE_TYPE
+#define RUST_COMPILE_TYPE
+
+#include "rust-compile-context.h"
+
+namespace Rust {
+namespace Compile {
+
+class TyTyResolveCompile : protected TyTy::TyConstVisitor
+{
+public:
+  static tree compile (Context *ctx, const TyTy::BaseType *ty,
+		       bool trait_object_mode = false);
+
+  static tree get_implicit_enumeral_node_type (Context *ctx);
+
+  void visit (const TyTy::InferType &) override;
+  void visit (const TyTy::ADTType &) override;
+  void visit (const TyTy::TupleType &) override;
+  void visit (const TyTy::FnType &) override;
+  void visit (const TyTy::FnPtr &) override;
+  void visit (const TyTy::ArrayType &) override;
+  void visit (const TyTy::SliceType &) override;
+  void visit (const TyTy::BoolType &) override;
+  void visit (const TyTy::IntType &) override;
+  void visit (const TyTy::UintType &) override;
+  void visit (const TyTy::FloatType &) override;
+  void visit (const TyTy::USizeType &) override;
+  void visit (const TyTy::ISizeType &) override;
+  void visit (const TyTy::ErrorType &) override;
+  void visit (const TyTy::CharType &) override;
+  void visit (const TyTy::ReferenceType &) override;
+  void visit (const TyTy::PointerType &) override;
+  void visit (const TyTy::ParamType &) override;
+  void visit (const TyTy::StrType &) override;
+  void visit (const TyTy::NeverType &) override;
+  void visit (const TyTy::PlaceholderType &) override;
+  void visit (const TyTy::ProjectionType &) override;
+  void visit (const TyTy::DynamicObjectType &) override;
+  void visit (const TyTy::ClosureType &) override;
+
+public:
+  static hashval_t type_hasher (tree type);
+
+protected:
+  tree create_slice_type_record (const TyTy::SliceType &type);
+  tree create_str_type_record (const TyTy::StrType &type);
+
+private:
+  TyTyResolveCompile (Context *ctx, bool trait_object_mode);
+
+  Context *ctx;
+  bool trait_object_mode;
+  tree translated;
+  int recurisve_ops;
+};
+
+} // namespace Compile
+} // namespace Rust
+
+#endif // RUST_COMPILE_TYPE
diff --git a/gcc/rust/backend/rust-compile-var-decl.h b/gcc/rust/backend/rust-compile-var-decl.h
new file mode 100644
index 00000000000..e2ee05b8163
--- /dev/null
+++ b/gcc/rust/backend/rust-compile-var-decl.h
@@ -0,0 +1,95 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_COMPILE_VAR_DECL
+#define RUST_COMPILE_VAR_DECL
+
+#include "rust-compile-base.h"
+#include "rust-hir-visitor.h"
+
+namespace Rust {
+namespace Compile {
+
+class CompileVarDecl : public HIRCompileBase, public HIR::HIRPatternVisitor
+{
+  using HIR::HIRPatternVisitor::visit;
+
+public:
+  static ::Bvariable *compile (tree fndecl, tree translated_type,
+			       HIR::Pattern *pattern, Context *ctx)
+  {
+    CompileVarDecl compiler (ctx, fndecl, translated_type);
+    pattern->accept_vis (compiler);
+    return compiler.compiled_variable;
+  }
+
+  void visit (HIR::IdentifierPattern &pattern) override
+  {
+    if (!pattern.is_mut ())
+      translated_type = ctx->get_backend ()->immutable_type (translated_type);
+
+    compiled_variable
+      = ctx->get_backend ()->local_variable (fndecl, pattern.get_identifier (),
+					     translated_type, NULL /*decl_var*/,
+					     pattern.get_locus ());
+
+    HirId stmt_id = pattern.get_pattern_mappings ().get_hirid ();
+    ctx->insert_var_decl (stmt_id, compiled_variable);
+  }
+
+  void visit (HIR::WildcardPattern &pattern) override
+  {
+    translated_type = ctx->get_backend ()->immutable_type (translated_type);
+
+    compiled_variable
+      = ctx->get_backend ()->local_variable (fndecl, "_", translated_type,
+					     NULL /*decl_var*/,
+					     pattern.get_locus ());
+
+    HirId stmt_id = pattern.get_pattern_mappings ().get_hirid ();
+    ctx->insert_var_decl (stmt_id, compiled_variable);
+  }
+
+  // Empty visit for unused Pattern HIR nodes.
+  void visit (HIR::GroupedPattern &) override {}
+  void visit (HIR::LiteralPattern &) override {}
+  void visit (HIR::PathInExpression &) override {}
+  void visit (HIR::QualifiedPathInExpression &) override {}
+  void visit (HIR::RangePattern &) override {}
+  void visit (HIR::ReferencePattern &) override {}
+  void visit (HIR::SlicePattern &) override {}
+  void visit (HIR::StructPattern &) override {}
+  void visit (HIR::TuplePattern &) override {}
+  void visit (HIR::TupleStructPattern &) override {}
+
+private:
+  CompileVarDecl (Context *ctx, tree fndecl, tree translated_type)
+    : HIRCompileBase (ctx), fndecl (fndecl), translated_type (translated_type),
+      compiled_variable (ctx->get_backend ()->error_variable ())
+  {}
+
+  tree fndecl;
+  tree translated_type;
+
+  Bvariable *compiled_variable;
+};
+
+} // namespace Compile
+} // namespace Rust
+
+#endif // RUST_COMPILE_VAR_DECL