ast: Add atomic type

Bug: tint:892
Change-Id: I00ab3e819a60762ff72b58f8a8255e56adadd71f
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/54644
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: James Price <jrprice@google.com>

src/BUILD.gn

@@ -304,6 +304,8 @@ libtint_source_set("libtint_core_all_src") {
     "ast/assignment_statement.cc",
     "ast/assignment_statement.h",
     "ast/ast_type.cc",  # TODO(bclayton) - rename to type.cc
+    "ast/atomic.cc",
+    "ast/atomic.h",
     "ast/binary_expression.cc",
     "ast/binary_expression.h",
     "ast/binding_decoration.cc",

src/CMakeLists.txt

@@ -48,6 +48,8 @@ set(TINT_LIB_SRCS
   ast/array.h
   ast/assignment_statement.cc
   ast/assignment_statement.h
+  ast/atomic.cc
+  ast/atomic.h
   ast/binary_expression.cc
   ast/binary_expression.h
   ast/binding_decoration.cc
@@ -515,6 +517,7 @@ if(${TINT_BUILD_TESTS})
     ast/array_accessor_expression_test.cc
     ast/array_test.cc
     ast/assignment_statement_test.cc
+    ast/atomic_test.cc
     ast/binary_expression_test.cc
     ast/binding_decoration_test.cc
     ast/bitcast_expression_test.cc

src/ast/atomic.cc

@@ -0,0 +1,51 @@
+// 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/atomic.h"
+
+#include "src/program_builder.h"
+
+TINT_INSTANTIATE_TYPEINFO(tint::ast::Atomic);
+
+namespace tint {
+namespace ast {
+
+Atomic::Atomic(ProgramID program_id, const Source& source, Type* const subtype)
+    : Base(program_id, source), subtype_(subtype) {}
+
+std::string Atomic::type_name() const {
+  std::ostringstream out;
+  out << "__atomic" << subtype_->type_name();
+  return out.str();
+}
+
+std::string Atomic::FriendlyName(const SymbolTable& symbols) const {
+  std::ostringstream out;
+  out << "atomic<" << subtype_->FriendlyName(symbols) << ">";
+  return out.str();
+}
+
+Atomic::Atomic(Atomic&&) = default;
+
+Atomic::~Atomic() = default;
+
+Atomic* Atomic::Clone(CloneContext* ctx) const {
+  // Clone arguments outside of create() call to have deterministic ordering
+  auto src = ctx->Clone(source());
+  auto* ty = ctx->Clone(type());
+  return ctx->dst->create<Atomic>(src, ty);
+}
+
+}  // namespace ast
+}  // namespace tint

src/ast/atomic.h

@@ -0,0 +1,60 @@
+// 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_ATOMIC_H_
+#define SRC_AST_ATOMIC_H_
+
+#include <string>
+
+#include "src/ast/type.h"
+
+namespace tint {
+namespace ast {
+
+/// An atomic type.
+class Atomic : public Castable<Atomic, Type> {
+ public:
+  /// Constructor
+  /// @param program_id the identifier of the program that owns this node
+  /// @param source the source of this node
+  /// @param subtype the pointee type
+  Atomic(ProgramID program_id, const Source& source, Type* const subtype);
+  /// Move constructor
+  Atomic(Atomic&&);
+  ~Atomic() override;
+
+  /// @returns the pointee type
+  Type* type() const { return const_cast<Type*>(subtype_); }
+
+  /// @returns the name for this type
+  std::string type_name() const override;
+
+  /// @param symbols the program's symbol table
+  /// @returns the name for this type that closely resembles how it would be
+  /// declared in WGSL.
+  std::string FriendlyName(const SymbolTable& symbols) const override;
+
+  /// Clones this type and all transitive types using the `CloneContext` `ctx`.
+  /// @param ctx the clone context
+  /// @return the newly cloned type
+  Atomic* Clone(CloneContext* ctx) const override;
+
+ private:
+  Type const* const subtype_;
+};
+
+}  // namespace ast
+}  // namespace tint
+
+#endif  // SRC_AST_ATOMIC_H_

src/ast/atomic_test.cc

@@ -0,0 +1,46 @@
+// 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/atomic.h"
+
+#include "src/ast/i32.h"
+#include "src/ast/test_helper.h"
+
+namespace tint {
+namespace ast {
+namespace {
+
+using AstAtomicTest = TestHelper;
+
+TEST_F(AstAtomicTest, Creation) {
+  auto* i32 = create<I32>();
+  auto* p = create<Atomic>(i32);
+  EXPECT_EQ(p->type(), i32);
+}
+
+TEST_F(AstAtomicTest, TypeName) {
+  auto* i32 = create<I32>();
+  auto* p = create<Atomic>(i32);
+  EXPECT_EQ(p->type_name(), "__atomic__i32");
+}
+
+TEST_F(AstAtomicTest, FriendlyName) {
+  auto* i32 = create<I32>();
+  auto* p = create<Atomic>(i32);
+  EXPECT_EQ(p->FriendlyName(Symbols()), "atomic<i32>");
+}
+
+}  // namespace
+}  // namespace ast
+}  // namespace tint

src/program_builder.h

@@ -22,6 +22,7 @@
 #include "src/ast/array.h"
 #include "src/ast/array_accessor_expression.h"
 #include "src/ast/assignment_statement.h"
+#include "src/ast/atomic.h"
 #include "src/ast/binary_expression.h"
 #include "src/ast/bool.h"
 #include "src/ast/bool_literal.h"
@@ -737,6 +738,19 @@ class ProgramBuilder {
       return pointer(Of<T>(), storage_class, access);
     }
 
+    /// @param source the Source of the node
+    /// @param type the type of the atomic
+    /// @return the atomic to `type`
+    ast::Atomic* atomic(const Source& source, ast::Type* type) const {
+      return builder->create<ast::Atomic>(source, type);
+    }
+
+    /// @return the atomic to type `T`
+    template <typename T>
+    ast::Atomic* atomic() const {
+      return atomic(Of<T>());
+    }
+
     /// @param kind the kind of sampler
     /// @returns the sampler
     ast::Sampler* sampler(ast::SamplerKind kind) const {

test/BUILD.gn

@@ -149,6 +149,7 @@ tint_unittests_source_set("tint_unittests_core_src") {
     "../src/ast/array_accessor_expression_test.cc",
     "../src/ast/array_test.cc",
     "../src/ast/assignment_statement_test.cc",
+    "../src/ast/atomic_test.cc",
     "../src/ast/binary_expression_test.cc",
     "../src/ast/binding_decoration_test.cc",
     "../src/ast/bitcast_expression_test.cc",