Add ast::InternalDecoration

An tint-internal decoration used to add metadata between a sanitizer transform and a backend.

Will be used for declaring backend-specific intrinsic calls.

Change-Id: Ia05ba7dada0148de2d490605ba4d15c593075356
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/46868
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: James Price <jrprice@google.com>

src/ast/function.cc

@@ -40,7 +40,6 @@ Function::Function(const Source& source,
   for (auto* param : params_) {
     TINT_ASSERT(param);
   }
-  TINT_ASSERT(body_);
   TINT_ASSERT(symbol_.IsValid());
   TINT_ASSERT(return_type_);
 }

src/ast/function.h

@@ -63,6 +63,18 @@ class Function : public Castable<Function, Node> {
   /// @returns the decorations attached to this function
   const DecorationList& decorations() const { return decorations_; }
 
+  /// @returns the decoration with the type `T` or nullptr if this function does
+  /// not contain a decoration with the given type
+  template <typename T>
+  const T* find_decoration() const {
+    for (auto* deco : decorations()) {
+      if (auto* d = deco->As<T>()) {
+        return d;
+      }
+    }
+    return nullptr;
+  }
+
   /// @returns the workgroup size {x, y, z} for the function. {1, 1, 1} will be
   /// return if no workgroup size was set.
   std::tuple<uint32_t, uint32_t, uint32_t> workgroup_size() const;

src/ast/internal_decoration.cc

@@ -0,0 +1,34 @@
+// 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/ast/internal_decoration.h"
+
+TINT_INSTANTIATE_TYPEINFO(tint::ast::InternalDecoration);
+
+namespace tint {
+namespace ast {
+
+InternalDecoration::InternalDecoration() : Base(Source{}) {}
+
+InternalDecoration::~InternalDecoration() = default;
+
+void InternalDecoration::to_str(const semantic::Info&,
+                                std::ostream& out,
+                                size_t indent) const {
+  make_indent(out, indent);
+  out << "tint_internal(" << Name() << ")" << std::endl;
+}
+
+}  // namespace ast
+}  // namespace tint

src/ast/internal_decoration.h

@@ -0,0 +1,53 @@
+// 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.
+
+#ifndef SRC_AST_INTERNAL_DECORATION_H_
+#define SRC_AST_INTERNAL_DECORATION_H_
+
+#include <string>
+
+#include "src/ast/decoration.h"
+
+namespace tint {
+namespace ast {
+
+/// A decoration used to indicate that a function is tint-internal.
+/// These decorations are not produced by generators, but instead are usually
+/// created by transforms for consumption by a particular backend.
+/// Functions annotated with this decoration will have relaxed validation.
+class InternalDecoration : public Castable<InternalDecoration, Decoration> {
+ public:
+  /// Constructor
+  InternalDecoration();
+
+  /// Destructor
+  ~InternalDecoration() override;
+
+  /// @return a short description of the internal decoration which will be
+  /// displayed in WGSL as `[[internal(<name>)]]` (but is not parsable).
+  virtual std::string Name() const = 0;
+
+  /// Writes a representation of the node to the output stream
+  /// @param sem the semantic info for the program
+  /// @param out the stream to write to
+  /// @param indent number of spaces to indent the node when writing
+  void to_str(const semantic::Info& sem,
+              std::ostream& out,
+              size_t indent) const override;
+};
+
+}  // namespace ast
+}  // namespace tint
+
+#endif  // SRC_AST_INTERNAL_DECORATION_H_