sem: Add FunctionBlockStatement

BlockStatement for the root block of a function

Add some basic tests for this lot.

Bug: tint:812
Change-Id: I26b65717798cbff576a44bd78fbcb5c8f0d013e6
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/51368
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Alastair Donaldson <allydonaldson@googlemail.com>

src/CMakeLists.txt

@@ -545,6 +545,7 @@ if(${TINT_BUILD_TESTS})
     intrinsic_table_test.cc
     program_test.cc
     resolver/assignment_validation_test.cc
+    resolver/block_test.cc
     resolver/builtins_validation_test.cc
     resolver/control_block_validation_test.cc
     resolver/decoration_validation_test.cc

src/resolver/block_test.cc

@@ -0,0 +1,77 @@
+// Copyright 2021 The Tint Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "src/resolver/resolver.h"
+
+#include "gmock/gmock.h"
+#include "src/resolver/resolver_test_helper.h"
+#include "src/sem/block_statement.h"
+
+namespace tint {
+namespace resolver {
+namespace {
+
+using ResolverBlockTest = ResolverTest;
+
+TEST_F(ResolverBlockTest, FunctionBlock) {
+  // fn F() {
+  //   var x : 32;
+  // }
+  auto* stmt = Decl(Var("x", ty.i32()));
+  auto* f = Func("F", {}, ty.void_(), {stmt});
+
+  ASSERT_TRUE(r()->Resolve()) << r()->error();
+
+  auto* s = Sem().Get(stmt);
+  ASSERT_NE(s, nullptr);
+  ASSERT_NE(s->Block(), nullptr);
+  ASSERT_TRUE(s->Block()->Is<sem::FunctionBlockStatement>());
+  EXPECT_EQ(s->Block(), s->Block()->FindFirstParent<sem::BlockStatement>());
+  EXPECT_EQ(s->Block(),
+            s->Block()->FindFirstParent<sem::FunctionBlockStatement>());
+  EXPECT_EQ(s->Block()->As<sem::FunctionBlockStatement>()->Function(), f);
+  EXPECT_EQ(s->Block()->Parent(), nullptr);
+}
+
+TEST_F(ResolverBlockTest, Block) {
+  // fn F() {
+  //   {
+  //     var x : 32;
+  //   }
+  // }
+  auto* stmt = Decl(Var("x", ty.i32()));
+  auto* block = Block(stmt);
+  auto* f = Func("F", {}, ty.void_(), {block});
+
+  ASSERT_TRUE(r()->Resolve()) << r()->error();
+
+  auto* s = Sem().Get(stmt);
+  ASSERT_NE(s, nullptr);
+  ASSERT_NE(s->Block(), nullptr);
+  ASSERT_NE(s->Block()->Parent(), nullptr);
+  EXPECT_EQ(s->Block(), s->Block()->FindFirstParent<sem::BlockStatement>());
+  EXPECT_EQ(s->Block()->Parent(),
+            s->Block()->FindFirstParent<sem::FunctionBlockStatement>());
+  ASSERT_TRUE(s->Block()->Parent()->Is<sem::FunctionBlockStatement>());
+  EXPECT_EQ(s->Block()->Parent()->As<sem::FunctionBlockStatement>()->Function(),
+            f);
+  EXPECT_EQ(s->Block()->Parent()->Parent(), nullptr);
+}
+
+// TODO(bclayton): Add tests for other block types (LoopBlockStatement,
+//                 LoopContinuingBlockStatement, SwitchCaseBlockStatement)
+
+}  // namespace
+}  // namespace resolver
+}  // namespace tint

src/resolver/resolver.cc

@@ -1228,8 +1228,7 @@ bool Resolver::Function(ast::Function* func) {
           << "Resolver::Function() called with a current statement";
       return false;
     }
-    auto* sem_block =
-        builder_->create<sem::BlockStatement>(func->body(), nullptr);
+    auto* sem_block = builder_->create<sem::FunctionBlockStatement>(func);
     builder_->Sem().Add(func->body(), sem_block);
     TINT_SCOPED_ASSIGNMENT(current_statement_, sem_block);
     if (!BlockScope(func->body(),

src/sem/block_statement.cc

@@ -15,8 +15,11 @@
 #include "src/sem/block_statement.h"
 
 #include "src/ast/block_statement.h"
+#include "src/ast/function.h"
+#include "src/sem/function.h"
 
 TINT_INSTANTIATE_TYPEINFO(tint::sem::BlockStatement);
+TINT_INSTANTIATE_TYPEINFO(tint::sem::FunctionBlockStatement);
 TINT_INSTANTIATE_TYPEINFO(tint::sem::LoopBlockStatement);
 TINT_INSTANTIATE_TYPEINFO(tint::sem::LoopContinuingBlockStatement);
 TINT_INSTANTIATE_TYPEINFO(tint::sem::SwitchCaseBlockStatement);
@@ -38,6 +41,11 @@ void BlockStatement::AddDecl(ast::Variable* var) {
   decls_.push_back(var);
 }
 
+FunctionBlockStatement::FunctionBlockStatement(const ast::Function* function)
+    : Base(function->body(), nullptr), function_(function) {}
+
+FunctionBlockStatement::~FunctionBlockStatement() = default;
+
 LoopBlockStatement::LoopBlockStatement(const ast::BlockStatement* declaration,
                                        const Statement* parent)
     : Base(declaration, parent) {}

src/sem/block_statement.h

@@ -19,14 +19,16 @@
 
 #include "src/sem/statement.h"
 
-namespace tint {
-
 // Forward declarations
+namespace tint {
 namespace ast {
 class BlockStatement;
+class Function;
 class Variable;
 }  // namespace ast
+}  // namespace tint
 
+namespace tint {
 namespace sem {
 
 /// Holds semantic information about a block, such as parent block and variables
@@ -84,6 +86,24 @@ class BlockStatement : public Castable<BlockStatement, Statement> {
   std::vector<const ast::Variable*> decls_;
 };
 
+/// The root block statement for a function
+class FunctionBlockStatement
+    : public Castable<FunctionBlockStatement, BlockStatement> {
+ public:
+  /// Constructor
+  /// @param function the owning function
+  explicit FunctionBlockStatement(const ast::Function* function);
+
+  /// Destructor
+  ~FunctionBlockStatement() override;
+
+  /// @returns the function owning this block
+  const ast::Function* Function() const { return function_; }
+
+ private:
+  ast::Function const* const function_;
+};
+
 /// Holds semantic information about a loop block
 class LoopBlockStatement : public Castable<LoopBlockStatement, BlockStatement> {
  public:

src/sem/statement.cc

@@ -65,5 +65,14 @@ const BlockStatement* Statement::Block() const {
   return nullptr;
 }
 
+const ast::Function* Statement::Function() const {
+  if (auto* block = Block()) {
+    if (auto* fbs = block->FindFirstParent<FunctionBlockStatement>()) {
+      return fbs->Function();
+    }
+  }
+  return nullptr;
+}
+
 }  // namespace sem
 }  // namespace tint

src/sem/statement.h

@@ -17,16 +17,19 @@
 
 #include "src/sem/node.h"
 
-namespace tint {
-
 // Forward declarations
+namespace tint {
 namespace ast {
+class Function;
 class Statement;
 }  // namespace ast
-
 namespace sem {
-
 class BlockStatement;
+}  // namespace sem
+}  // namespace tint
+
+namespace tint {
+namespace sem {
 
 /// Statement holds the semantic information for a statement.
 class Statement : public Castable<Statement, Node> {
@@ -45,6 +48,9 @@ class Statement : public Castable<Statement, Node> {
   /// @return the closest enclosing block for this statement
   const BlockStatement* Block() const;
 
+  /// @returns the function that owns this statement
+  const ast::Function* Function() const;
+
  private:
   ast::Statement const* const declaration_;
   Statement const* const parent_;

test/BUILD.gn

@@ -248,6 +248,7 @@ tint_unittests_source_set("tint_unittests_core_src") {
     "../src/program_builder_test.cc",
     "../src/program_test.cc",
     "../src/resolver/assignment_validation_test.cc",
+    "../src/resolver/block_test.cc",
     "../src/resolver/builtins_validation_test.cc",
     "../src/resolver/control_block_validation_test.cc",
     "../src/resolver/decoration_validation_test.cc",