Refactor backend to use finegrained visitors

This also moves more code out of the headers to their associated impl files
to improve compilation times and code navigation.

1 files changed, 115 insertions, 0 deletions

diff --git a/gcc/rust/backend/rust-compile-stmt.cc b/gcc/rust/backend/rust-compile-stmt.cc
new file mode 100644
index 0000000..bfb25f1
--- /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