[ast] Add constant_id decoration

This CL adds AST support for the constant_id decoration.

Bug: tint:150
Change-Id: Ifde5a5325f770567ea24129e786953d89f3f514b
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/29100
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Ryan Harrison <rharrison@chromium.org>

BUILD.gn

@@ -243,6 +243,8 @@ source_set("libtint_core_src") {
     "src/ast/call_statement.h",
     "src/ast/case_statement.cc",
     "src/ast/case_statement.h",
+    "src/ast/constant_id_decoration.cc",
+    "src/ast/constant_id_decoration.h",
     "src/ast/constructor_expression.cc",
     "src/ast/constructor_expression.h",
     "src/ast/continue_statement.cc",
@@ -695,6 +697,7 @@ source_set("tint_unittests_core_src") {
     "src/ast/call_expression_test.cc",
     "src/ast/call_statement_test.cc",
     "src/ast/case_statement_test.cc",
+    "src/ast/constant_id_decoration_test.cc",
     "src/ast/continue_statement_test.cc",
     "src/ast/decorated_variable_test.cc",
     "src/ast/discard_statement_test.cc",

src/CMakeLists.txt

@@ -64,6 +64,8 @@ set(TINT_LIB_SRCS
   ast/call_statement.h
   ast/case_statement.cc
   ast/case_statement.h
+  ast/constant_id_decoration.cc
+  ast/constant_id_decoration.h
   ast/constructor_expression.cc
   ast/constructor_expression.h
   ast/continue_statement.cc
@@ -304,6 +306,7 @@ set(TINT_TEST_SRCS
   ast/call_expression_test.cc
   ast/call_statement_test.cc
   ast/case_statement_test.cc
+  ast/constant_id_decoration_test.cc
   ast/continue_statement_test.cc
   ast/discard_statement_test.cc
   ast/decorated_variable_test.cc

src/ast/binding_decoration_test.cc

@@ -31,6 +31,7 @@ TEST_F(BindingDecorationTest, Is) {
   BindingDecoration d{2};
   EXPECT_TRUE(d.IsBinding());
   EXPECT_FALSE(d.IsBuiltin());
+  EXPECT_FALSE(d.IsConstantId());
   EXPECT_FALSE(d.IsLocation());
   EXPECT_FALSE(d.IsSet());
 }

src/ast/builtin_decoration_test.cc

@@ -31,6 +31,7 @@ TEST_F(BuiltinDecorationTest, Is) {
   BuiltinDecoration d{Builtin::kFragDepth};
   EXPECT_FALSE(d.IsBinding());
   EXPECT_TRUE(d.IsBuiltin());
+  EXPECT_FALSE(d.IsConstantId());
   EXPECT_FALSE(d.IsLocation());
   EXPECT_FALSE(d.IsSet());
 }

src/ast/constant_id_decoration.cc

@@ -0,0 +1,33 @@
+// Copyright 2020 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/ast/constant_id_decoration.h"
+
+namespace tint {
+namespace ast {
+
+ConstantIdDecoration::ConstantIdDecoration(uint32_t val) : value_(val) {}
+
+ConstantIdDecoration::~ConstantIdDecoration() = default;
+
+bool ConstantIdDecoration::IsConstantId() const {
+  return true;
+}
+
+void ConstantIdDecoration::to_str(std::ostream& out) const {
+  out << "ConstantIdDecoration{" << value_ << "}" << std::endl;
+}
+
+}  // namespace ast
+}  // namespace tint

src/ast/constant_id_decoration.h

@@ -0,0 +1,49 @@
+// Copyright 2020 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.
+
+#ifndef SRC_AST_CONSTANT_ID_DECORATION_H_
+#define SRC_AST_CONSTANT_ID_DECORATION_H_
+
+#include "src/ast/builtin.h"
+#include "src/ast/variable_decoration.h"
+
+namespace tint {
+namespace ast {
+
+/// A constant id decoration
+class ConstantIdDecoration : public VariableDecoration {
+ public:
+  /// constructor
+  /// @param val the constant_id value
+  explicit ConstantIdDecoration(uint32_t val);
+  ~ConstantIdDecoration() override;
+
+  /// @returns true if this is a constant_id decoration
+  bool IsConstantId() const override;
+
+  /// @returns the constant id value
+  uint32_t value() const { return value_; }
+
+  /// Outputs the decoration to the given stream
+  /// @param out the stream to output too
+  void to_str(std::ostream& out) const override;
+
+ private:
+  uint32_t value_ = 0;
+};
+
+}  // namespace ast
+}  // namespace tint
+
+#endif  // SRC_AST_CONSTANT_ID_DECORATION_H_

src/ast/constant_id_decoration_test.cc

@@ -0,0 +1,49 @@
+// Copyright 2020 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/ast/constant_id_decoration.h"
+
+#include "gtest/gtest.h"
+
+namespace tint {
+namespace ast {
+namespace {
+
+using ConstantIdDecorationTest = testing::Test;
+
+TEST_F(ConstantIdDecorationTest, Creation) {
+  ConstantIdDecoration d{12};
+  EXPECT_EQ(12u, d.value());
+}
+
+TEST_F(ConstantIdDecorationTest, Is) {
+  ConstantIdDecoration d{27};
+  EXPECT_FALSE(d.IsBinding());
+  EXPECT_FALSE(d.IsBuiltin());
+  EXPECT_TRUE(d.IsConstantId());
+  EXPECT_FALSE(d.IsLocation());
+  EXPECT_FALSE(d.IsSet());
+}
+
+TEST_F(ConstantIdDecorationTest, ToStr) {
+  ConstantIdDecoration d{1200};
+  std::ostringstream out;
+  d.to_str(out);
+  EXPECT_EQ(out.str(), R"(ConstantIdDecoration{1200}
+)");
+}
+
+}  // namespace
+}  // namespace ast
+}  // namespace tint

src/ast/location_decoration_test.cc

@@ -33,6 +33,7 @@ TEST_F(LocationDecorationTest, Is) {
   LocationDecoration d{2};
   EXPECT_FALSE(d.IsBinding());
   EXPECT_FALSE(d.IsBuiltin());
+  EXPECT_FALSE(d.IsConstantId());
   EXPECT_TRUE(d.IsLocation());
   EXPECT_FALSE(d.IsSet());
 }

src/ast/set_decoration_test.cc

@@ -31,6 +31,7 @@ TEST_F(SetDecorationTest, Is) {
   SetDecoration d{2};
   EXPECT_FALSE(d.IsBinding());
   EXPECT_FALSE(d.IsBuiltin());
+  EXPECT_FALSE(d.IsConstantId());
   EXPECT_FALSE(d.IsLocation());
   EXPECT_TRUE(d.IsSet());
 }

src/ast/variable_decoration.cc

@@ -18,6 +18,7 @@
 
 #include "src/ast/binding_decoration.h"
 #include "src/ast/builtin_decoration.h"
+#include "src/ast/constant_id_decoration.h"
 #include "src/ast/location_decoration.h"
 #include "src/ast/set_decoration.h"
 
@@ -40,6 +41,10 @@ bool VariableDecoration::IsLocation() const {
   return false;
 }
 
+bool VariableDecoration::IsConstantId() const {
+  return false;
+}
+
 bool VariableDecoration::IsSet() const {
   return false;
 }
@@ -54,6 +59,11 @@ BuiltinDecoration* VariableDecoration::AsBuiltin() {
   return static_cast<BuiltinDecoration*>(this);
 }
 
+ConstantIdDecoration* VariableDecoration::AsConstantId() {
+  assert(IsConstantId());
+  return static_cast<ConstantIdDecoration*>(this);
+}
+
 LocationDecoration* VariableDecoration::AsLocation() {
   assert(IsLocation());
   return static_cast<LocationDecoration*>(this);

src/ast/variable_decoration.h

@@ -25,6 +25,7 @@ namespace ast {
 
 class BindingDecoration;
 class BuiltinDecoration;
+class ConstantIdDecoration;
 class LocationDecoration;
 class SetDecoration;
 
@@ -37,6 +38,8 @@ class VariableDecoration {
   virtual bool IsBinding() const;
   /// @returns true if this is a builtin decoration
   virtual bool IsBuiltin() const;
+  /// @returns true if this is a constant id decoration
+  virtual bool IsConstantId() const;
   /// @returns true if this is a location decoration
   virtual bool IsLocation() const;
   /// @returns true if this is a set decoration
@@ -46,6 +49,8 @@ class VariableDecoration {
   BindingDecoration* AsBinding();
   /// @returns the decoration as a builtin decoration
   BuiltinDecoration* AsBuiltin();
+  /// @returns the decoration as a constant id decoration
+  ConstantIdDecoration* AsConstantId();
   /// @returns the decoration as a location decoration
   LocationDecoration* AsLocation();
   /// @returns the decoration as a set decoration