[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>
diff --git a/src/ast/constant_id_decoration.h b/src/ast/constant_id_decoration.h
new file mode 100644
index 0000000..c7b2d9a
--- /dev/null
+++ b/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_
