Add semantic::Variable, use it.

Pull the mutable semantic field from ast::Variable and into a new semantic::Variable node.
Have the TypeDeterminer create these semantic::Variable nodes.

Bug: tint:390
Change-Id: Ia13f5e7b065941ed66ea5a86c6ccb288071feff3
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/40063
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: David Neto <dneto@google.com>

src/ast/variable.cc

@@ -19,6 +19,7 @@
 #include "src/ast/constant_id_decoration.h"
 #include "src/clone_context.h"
 #include "src/program_builder.h"
+#include "src/semantic/variable.h"
 
 TINT_INSTANTIATE_CLASS_ID(tint::ast::Variable);
 
@@ -38,7 +39,7 @@ Variable::Variable(const Source& source,
       is_const_(is_const),
       constructor_(constructor),
       decorations_(std::move(decorations)),
-      storage_class_(sc) {}
+      declared_storage_class_(sc) {}
 
 Variable::Variable(Variable&&) = default;
 
@@ -91,10 +92,10 @@ uint32_t Variable::constant_id() const {
 }
 
 Variable* Variable::Clone(CloneContext* ctx) const {
-  return ctx->dst->create<Variable>(ctx->Clone(source()), ctx->Clone(symbol_),
-                                    storage_class(), ctx->Clone(type()),
-                                    is_const_, ctx->Clone(constructor()),
-                                    ctx->Clone(decorations_));
+  return ctx->dst->create<Variable>(
+      ctx->Clone(source()), ctx->Clone(symbol_), declared_storage_class(),
+      ctx->Clone(type()), is_const_, ctx->Clone(constructor()),
+      ctx->Clone(decorations_));
 }
 
 bool Variable::IsValid() const {
@@ -110,13 +111,15 @@ bool Variable::IsValid() const {
   return true;
 }
 
-void Variable::info_to_str(const semantic::Info&,
+void Variable::info_to_str(const semantic::Info& sem,
                            std::ostream& out,
                            size_t indent) const {
+  auto* var_sem = sem.Get(this);
   make_indent(out, indent);
   out << symbol_.to_str() << std::endl;
   make_indent(out, indent);
-  out << storage_class_ << std::endl;
+  out << (var_sem ? var_sem->StorageClass() : declared_storage_class())
+      << std::endl;
   make_indent(out, indent);
   out << type_->type_name() << std::endl;
 }

src/ast/variable.h

@@ -84,7 +84,7 @@ class Variable : public Castable<Variable, Node> {
   /// Create a variable
   /// @param source the variable source
   /// @param sym the variable symbol
-  /// @param sc the variable storage class
+  /// @param sc the declared storage class
   /// @param type the value type
   /// @param is_const true if the variable is const
   /// @param constructor the constructor expression
@@ -107,12 +107,10 @@ class Variable : public Castable<Variable, Node> {
   /// @returns the variable's type.
   type::Type* type() const { return type_; }
 
-  /// Sets the storage class
-  /// @param sc the storage class
-  void set_storage_class(StorageClass sc) { storage_class_ = sc; }
-  /// @returns the storage class
-  StorageClass storage_class() const { return storage_class_; }
-
+  /// @returns the declared storage class
+  StorageClass declared_storage_class() const {
+    return declared_storage_class_;
+  }
   /// @returns the constructor expression or nullptr if none set
   Expression* constructor() const { return constructor_; }
   /// @returns true if the variable has an constructor
@@ -126,7 +124,7 @@ class Variable : public Castable<Variable, Node> {
 
   /// @returns true if the decorations include a LocationDecoration
   bool HasLocationDecoration() const;
-  /// @returns true if the deocrations include a BuiltinDecoration
+  /// @returns true if the decorations include a BuiltinDecoration
   bool HasBuiltinDecoration() const;
   /// @returns true if the decorations include a ConstantIdDecoration
   bool HasConstantIdDecoration() const;
@@ -182,8 +180,7 @@ class Variable : public Castable<Variable, Node> {
   bool const is_const_;
   Expression* const constructor_;
   VariableDecorationList const decorations_;
-
-  StorageClass storage_class_ = StorageClass::kNone;  // Semantic info
+  StorageClass const declared_storage_class_;
 };
 
 /// A list of variables

src/ast/variable_test.cc

@@ -30,7 +30,7 @@ TEST_F(VariableTest, Creation) {
   auto* v = Var("my_var", StorageClass::kFunction, ty.i32());
 
   EXPECT_EQ(v->symbol(), Symbol(1));
-  EXPECT_EQ(v->storage_class(), StorageClass::kFunction);
+  EXPECT_EQ(v->declared_storage_class(), StorageClass::kFunction);
   EXPECT_EQ(v->type(), ty.i32());
   EXPECT_EQ(v->source().range.begin.line, 0u);
   EXPECT_EQ(v->source().range.begin.column, 0u);
@@ -44,7 +44,7 @@ TEST_F(VariableTest, CreationWithSource) {
       "i", StorageClass::kPrivate, ty.f32(), nullptr, VariableDecorationList{});
 
   EXPECT_EQ(v->symbol(), Symbol(1));
-  EXPECT_EQ(v->storage_class(), StorageClass::kPrivate);
+  EXPECT_EQ(v->declared_storage_class(), StorageClass::kPrivate);
   EXPECT_EQ(v->type(), ty.f32());
   EXPECT_EQ(v->source().range.begin.line, 27u);
   EXPECT_EQ(v->source().range.begin.column, 4u);
@@ -59,7 +59,7 @@ TEST_F(VariableTest, CreationEmpty) {
       VariableDecorationList{});
 
   EXPECT_EQ(v->symbol(), Symbol(1));
-  EXPECT_EQ(v->storage_class(), StorageClass::kWorkgroup);
+  EXPECT_EQ(v->declared_storage_class(), StorageClass::kWorkgroup);
   EXPECT_EQ(v->type(), ty.i32());
   EXPECT_EQ(v->source().range.begin.line, 27u);
   EXPECT_EQ(v->source().range.begin.column, 4u);