Add type determination for IdentifierExpression.

This CL adds the type determination for identifier expressions.
Namespaced identifiers are not determined yet.

Bug: tint:5
Change-Id: Id8f39ad122cef0349393de4d429a6d971b2a7ce8
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/18841
Reviewed-by: David Neto <dneto@google.com>

src/type_determiner.cc

@@ -19,6 +19,7 @@
 #include "src/ast/case_statement.h"
 #include "src/ast/continue_statement.h"
 #include "src/ast/else_statement.h"
+#include "src/ast/identifier_expression.h"
 #include "src/ast/if_statement.h"
 #include "src/ast/loop_statement.h"
 #include "src/ast/regardless_statement.h"
@@ -176,6 +177,9 @@ bool TypeDeterminer::DetermineResultType(ast::Expression* expr) {
   if (expr->IsConstructor()) {
     return DetermineConstructor(expr->AsConstructor());
   }
+  if (expr->IsIdentifier()) {
+    return DetermineIdentifier(expr->AsIdentifier());
+  }
 
   error_ = "unknown expression for type determination";
   return false;
@@ -190,4 +194,28 @@ bool TypeDeterminer::DetermineConstructor(ast::ConstructorExpression* expr) {
   return true;
 }
 
+bool TypeDeterminer::DetermineIdentifier(ast::IdentifierExpression* expr) {
+  if (expr->name().size() > 1) {
+    // TODO(dsinclair): Handle imports
+    error_ = "imports not handled in type determination";
+    return false;
+  }
+
+  auto name = expr->name()[0];
+  ast::Variable* var;
+  if (variable_stack_.get(name, &var)) {
+    expr->set_result_type(var->type());
+    return true;
+  }
+
+  auto iter = name_to_function_.find(name);
+  if (iter != name_to_function_.end()) {
+    expr->set_result_type(iter->second->return_type());
+    return true;
+  }
+
+  error_ = "unknown identifier for type determination";
+  return false;
+}
+
 }  // namespace tint

src/type_determiner.h

@@ -26,6 +26,7 @@ namespace tint {
 namespace ast {
 
 class ConstructorExpression;
+class IdentifierExpression;
 class Function;
 class Variable;
 
@@ -69,7 +70,7 @@ class TypeDeterminer {
 
  private:
   bool DetermineConstructor(ast::ConstructorExpression* expr);
-
+  bool DetermineIdentifier(ast::IdentifierExpression* expr);
   Context& ctx_;
   std::string error_;
   ScopeStack<ast::Variable*> variable_stack_;

src/type_determiner_test.cc

@@ -24,6 +24,7 @@
 #include "src/ast/continue_statement.h"
 #include "src/ast/else_statement.h"
 #include "src/ast/float_literal.h"
+#include "src/ast/identifier_expression.h"
 #include "src/ast/if_statement.h"
 #include "src/ast/int_literal.h"
 #include "src/ast/loop_statement.h"
@@ -406,5 +407,64 @@ TEST_F(TypeDeterminerTest, Expr_Constructor_Type) {
   EXPECT_EQ(tc.result_type()->AsVector()->size(), 3);
 }
 
+TEST_F(TypeDeterminerTest, Expr_Identifier_GlobalVariable) {
+  ast::type::F32Type f32;
+
+  ast::Module m;
+  auto var =
+      std::make_unique<ast::Variable>("my_var", ast::StorageClass::kNone, &f32);
+  m.AddGlobalVariable(std::move(var));
+
+  // Register the global
+  EXPECT_TRUE(td()->Determine(&m));
+
+  ast::IdentifierExpression ident("my_var");
+  EXPECT_TRUE(td()->DetermineResultType(&ident));
+  ASSERT_NE(ident.result_type(), nullptr);
+  EXPECT_TRUE(ident.result_type()->IsF32());
+}
+
+TEST_F(TypeDeterminerTest, Expr_Identifier_FunctionVariable) {
+  ast::type::F32Type f32;
+
+  auto my_var = std::make_unique<ast::IdentifierExpression>("my_var");
+  auto my_var_ptr = my_var.get();
+
+  ast::StatementList body;
+  body.push_back(std::make_unique<ast::VariableDeclStatement>(
+      std::make_unique<ast::Variable>("my_var", ast::StorageClass::kNone,
+                                      &f32)));
+
+  body.push_back(std::make_unique<ast::AssignmentStatement>(
+      std::move(my_var),
+      std::make_unique<ast::IdentifierExpression>("my_var")));
+
+  ast::Function f("my_func", {}, &f32);
+  f.set_body(std::move(body));
+
+  EXPECT_TRUE(td()->DetermineFunction(&f));
+
+  ASSERT_NE(my_var_ptr->result_type(), nullptr);
+  EXPECT_TRUE(my_var_ptr->result_type()->IsF32());
+}
+
+TEST_F(TypeDeterminerTest, Expr_Identifier_Function) {
+  ast::type::F32Type f32;
+
+  ast::VariableList params;
+  auto func =
+      std::make_unique<ast::Function>("my_func", std::move(params), &f32);
+  ast::Module m;
+  m.AddFunction(std::move(func));
+
+  // Register the function
+  EXPECT_TRUE(td()->Determine(&m));
+
+  ast::IdentifierExpression ident("my_func");
+  EXPECT_TRUE(td()->DetermineResultType(&ident));
+  ASSERT_NE(ident.result_type(), nullptr);
+  EXPECT_TRUE(ident.result_type()->IsF32());
+}
+
 }  // namespace
 }  // namespace tint