|  | // Copyright 2024 The Dawn & Tint Authors | 
|  | // | 
|  | // Redistribution and use in source and binary forms, with or without | 
|  | // modification, are permitted provided that the following conditions are met: | 
|  | // | 
|  | // 1. Redistributions of source code must retain the above copyright notice, this | 
|  | //    list of conditions and the following disclaimer. | 
|  | // | 
|  | // 2. Redistributions in binary form must reproduce the above copyright notice, | 
|  | //    this list of conditions and the following disclaimer in the documentation | 
|  | //    and/or other materials provided with the distribution. | 
|  | // | 
|  | // 3. Neither the name of the copyright holder nor the names of its | 
|  | //    contributors may be used to endorse or promote products derived from | 
|  | //    this software without specific prior written permission. | 
|  | // | 
|  | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | 
|  | // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | 
|  | // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE | 
|  | // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE | 
|  | // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | 
|  | // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR | 
|  | // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER | 
|  | // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, | 
|  | // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | 
|  | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | 
|  |  | 
|  | #ifndef SRC_UTILS_COMPILER_H_ | 
|  | #define SRC_UTILS_COMPILER_H_ | 
|  |  | 
|  | // DAWN_COMPILER_IS(CLANG|GCC|MSVC): Compiler detection | 
|  | // | 
|  | // Note: clang masquerades as GCC on POSIX and as MSVC on Windows. It must be checked first. | 
|  | #if defined(__clang__) | 
|  | #define DAWN_COMPILER_IS_CLANG 1 | 
|  | #define DAWN_COMPILER_IS_GCC 0 | 
|  | #define DAWN_COMPILER_IS_MSVC 0 | 
|  | #elif defined(__GNUC__) | 
|  | #define DAWN_COMPILER_IS_CLANG 0 | 
|  | #define DAWN_COMPILER_IS_GCC 1 | 
|  | #define DAWN_COMPILER_IS_MSVC 0 | 
|  | #elif defined(_MSC_VER) | 
|  | #define DAWN_COMPILER_IS_CLANG 0 | 
|  | #define DAWN_COMPILER_IS_GCC 0 | 
|  | #define DAWN_COMPILER_IS_MSVC 1 | 
|  | #else | 
|  | #error "Unsupported compiler" | 
|  | #endif | 
|  |  | 
|  | // Use #if DAWN_COMPILER_IS(XXX) for compiler specific code. | 
|  | // Do not use #ifdef or the naked macro DAWN_COMPILER_IS_XXX. | 
|  | // This can help avoid common mistakes like not including "compiler.h" and falling into unwanted | 
|  | // code block as usage of undefined macro "function" will be blocked by the compiler. | 
|  | #define DAWN_COMPILER_IS(X) (1 == DAWN_COMPILER_IS_##X) | 
|  |  | 
|  | // DAWN_HAS_ATTRIBUTE | 
|  | // | 
|  | // A wrapper around `__has_attribute`. This test whether its operand is recognized by the compiler. | 
|  | #if defined(__has_attribute) | 
|  | #define DAWN_HAS_ATTRIBUTE(x) __has_attribute(x) | 
|  | #else | 
|  | #define DAWN_HAS_ATTRIBUTE(x) 0 | 
|  | #endif | 
|  |  | 
|  | // DAWN_HAS_CPP_ATTRIBUTE | 
|  | // | 
|  | // A wrapper around `__has_cpp_attribute`. This test whether its operand is recognized by the | 
|  | // compiler. | 
|  | #if defined(__has_cpp_attribute) | 
|  | #define DAWN_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x) | 
|  | #else | 
|  | #define DAWN_HAS_CPP_ATTRIBUTE(x) 0 | 
|  | #endif | 
|  |  | 
|  | // DAWN_BUILTIN_UNREACHABLE() | 
|  | // | 
|  | // Hints the compiler that a code path is unreachable. | 
|  | #if DAWN_COMPILER_IS(MSVC) | 
|  | #define DAWN_BUILTIN_UNREACHABLE() __assume(false) | 
|  | #else | 
|  | #define DAWN_BUILTIN_UNREACHABLE() __builtin_unreachable() | 
|  | #endif | 
|  |  | 
|  | // DAWN_LIKELY(EXPR) | 
|  | // | 
|  | // Where available, hints the compiler that the expression will be true to help it generate code | 
|  | // that leads to better branch prediction. | 
|  | #if DAWN_COMPILER_IS(GCC) || DAWN_COMPILER_IS(CLANG) | 
|  | #define DAWN_LIKELY(x) __builtin_expect(!!(x), 1) | 
|  | #else | 
|  | #define DAWN_LIKELY(x) (x) | 
|  | #endif | 
|  |  | 
|  | // DAWN_UNLIKELY(EXPR) | 
|  | // | 
|  | // Where available, hints the compiler that the expression will be false to help it generate code | 
|  | // that leads to better branch prediction. | 
|  | #if DAWN_COMPILER_IS(GCC) || DAWN_COMPILER_IS(CLANG) | 
|  | #define DAWN_UNLIKELY(x) __builtin_expect(!!(x), 0) | 
|  | #else | 
|  | #define DAWN_UNLIKELY(x) (x) | 
|  | #endif | 
|  |  | 
|  | // DAWN_ASAN_ENABLED() | 
|  | // | 
|  | // Checks whether ASan is enabled. | 
|  | #if DAWN_COMPILER_IS(CLANG) | 
|  | #define DAWN_ASAN_ENABLED() __has_feature(address_sanitizer) | 
|  | #elif DAWN_COMPILER_IS(GCC) || DAWN_COMPILER_IS(MSVC) | 
|  | #if defined(__SANITIZE_ADDRESS__) | 
|  | #define DAWN_ASAN_ENABLED() 1 | 
|  | #else | 
|  | #define DAWN_ASAN_ENABLED() 0 | 
|  | #endif | 
|  | #endif | 
|  |  | 
|  | // DAWN_NO_SANITIZE(instrumentation) | 
|  | // | 
|  | // Annotate a function or a global variable declaration to specify that a particular instrumentation | 
|  | // or set of instrumentations should not be applied. | 
|  | #if DAWN_HAS_ATTRIBUTE(no_sanitize) | 
|  | #define DAWN_NO_SANITIZE(instrumentation) __attribute__((no_sanitize(instrumentation))) | 
|  | #else | 
|  | #define DAWN_NO_SANITIZE(instrumentation) | 
|  | #endif | 
|  |  | 
|  | #endif  // SRC_UTILS_COMPILER_H_ |