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v8/include/cppgc/internal/compiler-specific.h

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+// Copyright 2020 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef INCLUDE_CPPGC_INTERNAL_COMPILER_SPECIFIC_H_
+#define INCLUDE_CPPGC_INTERNAL_COMPILER_SPECIFIC_H_
+
+namespace cppgc {
+
+#if defined(__has_attribute)
+#define CPPGC_HAS_ATTRIBUTE(FEATURE) __has_attribute(FEATURE)
+#else
+#define CPPGC_HAS_ATTRIBUTE(FEATURE) 0
+#endif
+
+#if defined(__has_cpp_attribute)
+#define CPPGC_HAS_CPP_ATTRIBUTE(FEATURE) __has_cpp_attribute(FEATURE)
+#else
+#define CPPGC_HAS_CPP_ATTRIBUTE(FEATURE) 0
+#endif
+
+// [[no_unique_address]] comes in C++20 but supported in clang with -std >=
+// c++11.
+#if CPPGC_HAS_CPP_ATTRIBUTE(no_unique_address)
+#define CPPGC_NO_UNIQUE_ADDRESS [[no_unique_address]]
+#else
+#define CPPGC_NO_UNIQUE_ADDRESS
+#endif
+
+#if CPPGC_HAS_ATTRIBUTE(unused)
+#define CPPGC_UNUSED __attribute__((unused))
+#else
+#define CPPGC_UNUSED
+#endif
+
+}  // namespace cppgc
+
+#endif  // INCLUDE_CPPGC_INTERNAL_COMPILER_SPECIFIC_H_