[gcc r14-8573] gccrs: Remove backend dependancy on resolution rib information

[gcc r14-8573] gccrs: Remove backend dependancy on resolution rib information

[Arthur Cohen]

https://gcc.gnu.org/g:b4fc851e3a01e708819ebfe1bfe4f2dc2ae9e5e7

commit r14-8573-gb4fc851e3a01e708819ebfe1bfe4f2dc2ae9e5e7
Author: Philip Herron <herron.philip@googlemail.com>
Date:   Mon Oct 2 18:41:33 2023 +0100

    gccrs: Remove backend dependancy on resolution rib information
    
    When making more desugaring for the HIR we can need to add new Let bindings
    which will require namesolution information but also rib information for
    which block the let binding is associated which was very unnessecary. This
    patch simply updates the BLOCK_CONTEXT of the current scope as we are
    compiling and encounter HIR::LetStmts instead of trying to do it all
    upfront which lots of wierd checks
    
    gcc/rust/ChangeLog:
    
            * backend/rust-compile-base.cc (HIRCompileBase::compile_locals_for_block): removed
            * backend/rust-compile-base.h: update header
            * backend/rust-compile-block.cc (CompileBlock::visit): remove old logic
            * backend/rust-compile-expr.cc (CompileExpr::generate_closure_function): likewise
            * backend/rust-compile-stmt.cc (CompileStmt::visit): likewise
            * backend/rust-compile-var-decl.h: ensure we setup tuple bindings correctly
    
    Signed-off-by: Philip Herron <herron.philip@googlemail.com>

Diff:
---
 gcc/rust/backend/rust-compile-base.cc    | 51 +----------------------
 gcc/rust/backend/rust-compile-base.h     |  3 --
 gcc/rust/backend/rust-compile-block.cc   | 13 +-----
 gcc/rust/backend/rust-compile-expr.cc    |  5 +--
 gcc/rust/backend/rust-compile-stmt.cc    | 16 ++++++--
 gcc/rust/backend/rust-compile-var-decl.h | 69 +++++++++++++++++++++++++-------
 6 files changed, 71 insertions(+), 86 deletions(-)

diff --git a/gcc/rust/backend/rust-compile-base.cc b/gcc/rust/backend/rust-compile-base.cc
index ae9f6707b727..fcab75bef1c7 100644
--- a/gcc/rust/backend/rust-compile-base.cc
+++ b/gcc/rust/backend/rust-compile-base.cc
@@ -564,35 +564,6 @@ HIRCompileBase::indirect_expression (tree expr, location_t locus)
   return build_fold_indirect_ref_loc (locus, expr);
 }
 
-std::vector<Bvariable *>
-HIRCompileBase::compile_locals_for_block (Context *ctx, Resolver::Rib &rib,
-					  tree fndecl)
-{
-  std::vector<Bvariable *> locals;
-  for (auto it : rib.get_declarations ())
-    {
-      NodeId node_id = it.first;
-      HirId ref = UNKNOWN_HIRID;
-      if (!ctx->get_mappings ()->lookup_node_to_hir (node_id, &ref))
-	continue;
-
-      // we only care about local patterns
-      HIR::Pattern *pattern = ctx->get_mappings ()->lookup_hir_pattern (ref);
-      if (pattern == nullptr)
-	continue;
-
-      // lookup the type
-      TyTy::BaseType *tyty = nullptr;
-      if (!ctx->get_tyctx ()->lookup_type (ref, &tyty))
-	continue;
-
-      // compile the local
-      tree type = TyTyResolveCompile::compile (ctx, tyty);
-      CompileVarDecl::compile (fndecl, type, pattern, locals, ctx);
-    }
-  return locals;
-}
-
 void
 HIRCompileBase::compile_function_body (tree fndecl,
 				       HIR::BlockExpr &function_body,
@@ -750,21 +721,11 @@ HIRCompileBase::compile_function (
   if (!Backend::function_set_parameters (fndecl, param_vars))
     return error_mark_node;
 
-  // lookup locals
-  auto body_mappings = function_body->get_mappings ();
-  Resolver::Rib *rib = nullptr;
-  bool ok
-    = ctx->get_resolver ()->find_name_rib (body_mappings.get_nodeid (), &rib);
-  rust_assert (ok);
-
-  std::vector<Bvariable *> locals
-    = compile_locals_for_block (ctx, *rib, fndecl);
-
   tree enclosing_scope = NULL_TREE;
   location_t start_location = function_body->get_locus ();
   location_t end_location = function_body->get_end_locus ();
 
-  tree code_block = Backend::block (fndecl, enclosing_scope, locals,
+  tree code_block = Backend::block (fndecl, enclosing_scope, {} /*locals*/,
 				    start_location, end_location);
   ctx->push_block (code_block);
 
@@ -820,7 +781,6 @@ HIRCompileBase::compile_constant_item (
   tree fndecl = Backend::function (compiled_fn_type, ident, "", 0, locus);
   TREE_READONLY (fndecl) = 1;
 
-  std::vector<Bvariable *> locals;
   tree enclosing_scope = NULL_TREE;
   location_t start_location = const_value_expr->get_locus ();
   location_t end_location = const_value_expr->get_locus ();
@@ -830,16 +790,9 @@ HIRCompileBase::compile_constant_item (
 	= static_cast<HIR::BlockExpr *> (const_value_expr);
       start_location = function_body->get_locus ();
       end_location = function_body->get_end_locus ();
-
-      Resolver::Rib *rib = nullptr;
-      bool ok = ctx->get_resolver ()->find_name_rib (
-	function_body->get_mappings ().get_nodeid (), &rib);
-      rust_assert (ok);
-
-      locals = compile_locals_for_block (ctx, *rib, fndecl);
     }
 
-  tree code_block = Backend::block (fndecl, enclosing_scope, locals,
+  tree code_block = Backend::block (fndecl, enclosing_scope, {} /*locals*/,
 				    start_location, end_location);
   ctx->push_block (code_block);
 
diff --git a/gcc/rust/backend/rust-compile-base.h b/gcc/rust/backend/rust-compile-base.h
index 65291234b238..c5816584c724 100644
--- a/gcc/rust/backend/rust-compile-base.h
+++ b/gcc/rust/backend/rust-compile-base.h
@@ -145,9 +145,6 @@ protected:
 
   static bool mark_addressable (tree, location_t);
 
-  static std::vector<Bvariable *>
-  compile_locals_for_block (Context *ctx, Resolver::Rib &rib, tree fndecl);
-
   static tree named_constant_expression (tree type_tree,
 					 const std::string &name,
 					 tree const_val, location_t location);
diff --git a/gcc/rust/backend/rust-compile-block.cc b/gcc/rust/backend/rust-compile-block.cc
index 83ecc6725928..10a709997735 100644
--- a/gcc/rust/backend/rust-compile-block.cc
+++ b/gcc/rust/backend/rust-compile-block.cc
@@ -42,20 +42,9 @@ CompileBlock::visit (HIR::BlockExpr &expr)
   tree fndecl = fnctx.fndecl;
   location_t start_location = expr.get_locus ();
   location_t 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 = Backend::block (fndecl, enclosing_scope, locals,
+  tree new_block = Backend::block (fndecl, enclosing_scope, {} /*locals*/,
 				   start_location, end_location);
   ctx->push_block (new_block);
 
diff --git a/gcc/rust/backend/rust-compile-expr.cc b/gcc/rust/backend/rust-compile-expr.cc
index 870ecab5ba0b..e0917f686602 100644
--- a/gcc/rust/backend/rust-compile-expr.cc
+++ b/gcc/rust/backend/rust-compile-expr.cc
@@ -2310,7 +2310,6 @@ CompileExpr::generate_closure_function (HIR::ClosureExpr &expr,
   bool is_block_expr
     = function_body->get_expression_type () == HIR::Expr::ExprType::Block;
 
-  std::vector<Bvariable *> locals = {};
   if (is_block_expr)
     {
       auto body_mappings = function_body->get_mappings ();
@@ -2319,8 +2318,6 @@ CompileExpr::generate_closure_function (HIR::ClosureExpr &expr,
 	= ctx->get_resolver ()->find_name_rib (body_mappings.get_nodeid (),
 					       &rib);
       rust_assert (ok);
-
-      locals = compile_locals_for_block (ctx, *rib, fndecl);
     }
 
   tree enclosing_scope = NULL_TREE;
@@ -2333,7 +2330,7 @@ CompileExpr::generate_closure_function (HIR::ClosureExpr &expr,
       end_location = body->get_end_locus ();
     }
 
-  tree code_block = Backend::block (fndecl, enclosing_scope, locals,
+  tree code_block = Backend::block (fndecl, enclosing_scope, {} /*locals*/,
 				    start_location, end_location);
   ctx->push_block (code_block);
 
diff --git a/gcc/rust/backend/rust-compile-stmt.cc b/gcc/rust/backend/rust-compile-stmt.cc
index c006f4ace628..e7ba370eb8e0 100644
--- a/gcc/rust/backend/rust-compile-stmt.cc
+++ b/gcc/rust/backend/rust-compile-stmt.cc
@@ -19,6 +19,8 @@
 #include "rust-compile-pattern.h"
 #include "rust-compile-stmt.h"
 #include "rust-compile-expr.h"
+#include "rust-compile-type.h"
+#include "rust-compile-var-decl.h"
 
 namespace Rust {
 namespace Compile {
@@ -44,10 +46,6 @@ CompileStmt::visit (HIR::ExprStmt &stmt)
 void
 CompileStmt::visit (HIR::LetStmt &stmt)
 {
-  // nothing to do
-  if (!stmt.has_init_expr ())
-    return;
-
   HIR::Pattern &stmt_pattern = *stmt.get_pattern ();
   HirId stmt_id = stmt_pattern.get_mappings ().get_hirid ();
 
@@ -60,6 +58,16 @@ CompileStmt::visit (HIR::LetStmt &stmt)
       return;
     }
 
+  // setup var decl nodes
+  fncontext fnctx = ctx->peek_fn ();
+  tree fndecl = fnctx.fndecl;
+  tree translated_type = TyTyResolveCompile::compile (ctx, ty);
+  CompileVarDecl::compile (fndecl, translated_type, &stmt_pattern, ctx);
+
+  // nothing to do
+  if (!stmt.has_init_expr ())
+    return;
+
   tree init = CompileExpr::Compile (stmt.get_init_expr ().get (), ctx);
   // FIXME use error_mark_node, check that CompileExpr returns error_mark_node
   // on failure and make this an assertion
diff --git a/gcc/rust/backend/rust-compile-var-decl.h b/gcc/rust/backend/rust-compile-var-decl.h
index 370e939cd0ce..45ca01d4f709 100644
--- a/gcc/rust/backend/rust-compile-var-decl.h
+++ b/gcc/rust/backend/rust-compile-var-decl.h
@@ -30,11 +30,12 @@ class CompileVarDecl : public HIRCompileBase, public HIR::HIRPatternVisitor
   using HIR::HIRPatternVisitor::visit;
 
 public:
-  static void compile (tree fndecl, tree translated_type, HIR::Pattern *pattern,
-		       std::vector<Bvariable *> &locals, Context *ctx)
+  static std::vector<Bvariable *> compile (tree fndecl, tree translated_type,
+					   HIR::Pattern *pattern, Context *ctx)
   {
-    CompileVarDecl compiler (ctx, fndecl, translated_type, locals);
+    CompileVarDecl compiler (ctx, fndecl, translated_type);
     pattern->accept_vis (compiler);
+    return compiler.vars;
   }
 
   void visit (HIR::IdentifierPattern &pattern) override
@@ -42,15 +43,58 @@ public:
     if (!pattern.is_mut ())
       translated_type = Backend::immutable_type (translated_type);
 
-    Bvariable *var
-      = Backend::local_variable (fndecl, pattern.get_identifier ().as_string (),
-				 translated_type, NULL /*decl_var*/,
-				 pattern.get_locus ());
+    tree bind_tree = ctx->peek_enclosing_scope ();
+    std::string identifier = pattern.get_identifier ().as_string ();
+    tree decl
+      = build_decl (pattern.get_locus (), VAR_DECL,
+		    Backend::get_identifier_node (identifier), translated_type);
+    DECL_CONTEXT (decl) = fndecl;
+
+    gcc_assert (TREE_CODE (bind_tree) == BIND_EXPR);
+    tree block_tree = BIND_EXPR_BLOCK (bind_tree);
+    gcc_assert (TREE_CODE (block_tree) == BLOCK);
+    DECL_CHAIN (decl) = BLOCK_VARS (block_tree);
+    BLOCK_VARS (block_tree) = decl;
+    BIND_EXPR_VARS (bind_tree) = BLOCK_VARS (block_tree);
+
+    rust_preserve_from_gc (decl);
+    Bvariable *var = new Bvariable (decl);
 
     HirId stmt_id = pattern.get_mappings ().get_hirid ();
     ctx->insert_var_decl (stmt_id, var);
 
-    locals.push_back (var);
+    vars.push_back (var);
+  }
+
+  void visit (HIR::TuplePattern &pattern) override
+  {
+    switch (pattern.get_items ()->get_item_type ())
+      {
+	case HIR::TuplePatternItems::ItemType::MULTIPLE: {
+	  rust_assert (TREE_CODE (translated_type) == RECORD_TYPE);
+	  auto &items = static_cast<HIR::TuplePatternItemsMultiple &> (
+	    *pattern.get_items ());
+
+	  size_t offs = 0;
+	  for (auto &sub : items.get_patterns ())
+	    {
+	      tree sub_ty = error_mark_node;
+	      tree field = TYPE_FIELDS (translated_type);
+	      for (size_t i = 0; i < offs; i++)
+		{
+		  field = DECL_CHAIN (field);
+		  gcc_assert (field != NULL_TREE);
+		}
+	      sub_ty = TREE_TYPE (field);
+	      CompileVarDecl::compile (fndecl, sub_ty, sub.get (), ctx);
+	      offs++;
+	    }
+	}
+	break;
+
+      default:
+	break;
+      }
   }
 
   // Empty visit for unused Pattern HIR nodes.
@@ -62,21 +106,18 @@ public:
   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 {}
 
 private:
-  CompileVarDecl (Context *ctx, tree fndecl, tree translated_type,
-		  std::vector<Bvariable *> &locals)
-    : HIRCompileBase (ctx), fndecl (fndecl), translated_type (translated_type),
-      locals (locals)
+  CompileVarDecl (Context *ctx, tree fndecl, tree translated_type)
+    : HIRCompileBase (ctx), fndecl (fndecl), translated_type (translated_type)
   {}
 
   tree fndecl;
   tree translated_type;
 
-  std::vector<Bvariable *> &locals;
+  std::vector<Bvariable *> vars;
 };
 
 } // namespace Compile