| // Copyright (c) 2012 The Chromium 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 THIRD_PARTY_BASE_COMPILER_SPECIFIC_H_ |
| #define THIRD_PARTY_BASE_COMPILER_SPECIFIC_H_ |
| |
| #include "build/build_config.h" |
| |
| // Annotate a variable indicating it's ok if the variable is not used. |
| // (Typically used to silence a compiler warning when the assignment |
| // is important for some other reason.) |
| // Use like: |
| // int x = ...; |
| // ALLOW_UNUSED_LOCAL(x); |
| #define ALLOW_UNUSED_LOCAL(x) (void)x |
| |
| // Annotate a typedef or function indicating it's ok if it's not used. |
| // Use like: |
| // typedef Foo Bar ALLOW_UNUSED_TYPE; |
| #if defined(COMPILER_GCC) || defined(__clang__) |
| #define ALLOW_UNUSED_TYPE __attribute__((unused)) |
| #else |
| #define ALLOW_UNUSED_TYPE |
| #endif |
| |
| // Annotate a function indicating it should not be inlined. |
| // Use like: |
| // NOINLINE void DoStuff() { ... } |
| #if defined(COMPILER_GCC) |
| #define NOINLINE __attribute__((noinline)) |
| #elif defined(COMPILER_MSVC) |
| #define NOINLINE __declspec(noinline) |
| #else |
| #define NOINLINE |
| #endif |
| |
| #if defined(COMPILER_GCC) && defined(NDEBUG) |
| #define ALWAYS_INLINE inline __attribute__((__always_inline__)) |
| #elif defined(COMPILER_MSVC) && defined(NDEBUG) |
| #define ALWAYS_INLINE __forceinline |
| #else |
| #define ALWAYS_INLINE inline |
| #endif |
| |
| // Specify memory alignment for structs, classes, etc. |
| // Use like: |
| // class ALIGNAS(16) MyClass { ... } |
| // ALIGNAS(16) int array[4]; |
| // |
| // In most places you can use the C++11 keyword "alignas", which is preferred. |
| // |
| // But compilers have trouble mixing __attribute__((...)) syntax with |
| // alignas(...) syntax. |
| // |
| // Doesn't work in clang or gcc: |
| // struct alignas(16) __attribute__((packed)) S { char c; }; |
| // Works in clang but not gcc: |
| // struct __attribute__((packed)) alignas(16) S2 { char c; }; |
| // Works in clang and gcc: |
| // struct alignas(16) S3 { char c; } __attribute__((packed)); |
| // |
| // There are also some attributes that must be specified *before* a class |
| // definition: visibility (used for exporting functions/classes) is one of |
| // these attributes. This means that it is not possible to use alignas() with a |
| // class that is marked as exported. |
| #if defined(COMPILER_MSVC) |
| #define ALIGNAS(byte_alignment) __declspec(align(byte_alignment)) |
| #elif defined(COMPILER_GCC) |
| #define ALIGNAS(byte_alignment) __attribute__((aligned(byte_alignment))) |
| #endif |
| |
| // Annotate a function indicating the caller must examine the return value. |
| // Use like: |
| // int foo() WARN_UNUSED_RESULT; |
| // To explicitly ignore a result, see |ignore_result()| in base/macros.h. |
| #undef WARN_UNUSED_RESULT |
| #if defined(COMPILER_GCC) || defined(__clang__) |
| #define WARN_UNUSED_RESULT __attribute__((warn_unused_result)) |
| #else |
| #define WARN_UNUSED_RESULT |
| #endif |
| |
| // Tell the compiler a function is using a printf-style format string. |
| // |format_param| is the one-based index of the format string parameter; |
| // |dots_param| is the one-based index of the "..." parameter. |
| // For v*printf functions (which take a va_list), pass 0 for dots_param. |
| // (This is undocumented but matches what the system C headers do.) |
| #if defined(COMPILER_GCC) || defined(__clang__) |
| #define PRINTF_FORMAT(format_param, dots_param) \ |
| __attribute__((format(printf, format_param, dots_param))) |
| #else |
| #define PRINTF_FORMAT(format_param, dots_param) |
| #endif |
| |
| // WPRINTF_FORMAT is the same, but for wide format strings. |
| // This doesn't appear to yet be implemented in any compiler. |
| // See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38308 . |
| #define WPRINTF_FORMAT(format_param, dots_param) |
| // If available, it would look like: |
| // __attribute__((format(wprintf, format_param, dots_param))) |
| |
| // Sanitizers annotations. |
| #if defined(__has_attribute) |
| #if __has_attribute(no_sanitize) |
| #define NO_SANITIZE(what) __attribute__((no_sanitize(what))) |
| #endif |
| #endif |
| #if !defined(NO_SANITIZE) |
| #define NO_SANITIZE(what) |
| #endif |
| |
| // MemorySanitizer annotations. |
| #if defined(MEMORY_SANITIZER) && !defined(OS_NACL) |
| #include <sanitizer/msan_interface.h> |
| |
| // Mark a memory region fully initialized. |
| // Use this to annotate code that deliberately reads uninitialized data, for |
| // example a GC scavenging root set pointers from the stack. |
| #define MSAN_UNPOISON(p, size) __msan_unpoison(p, size) |
| |
| // Check a memory region for initializedness, as if it was being used here. |
| // If any bits are uninitialized, crash with an MSan report. |
| // Use this to sanitize data which MSan won't be able to track, e.g. before |
| // passing data to another process via shared memory. |
| #define MSAN_CHECK_MEM_IS_INITIALIZED(p, size) \ |
| __msan_check_mem_is_initialized(p, size) |
| #else // MEMORY_SANITIZER |
| #define MSAN_UNPOISON(p, size) |
| #define MSAN_CHECK_MEM_IS_INITIALIZED(p, size) |
| #endif // MEMORY_SANITIZER |
| |
| // DISABLE_CFI_PERF -- Disable Control Flow Integrity for perf reasons. |
| #if !defined(DISABLE_CFI_PERF) |
| #if defined(__clang__) && defined(OFFICIAL_BUILD) |
| #define DISABLE_CFI_PERF __attribute__((no_sanitize("cfi"))) |
| #else |
| #define DISABLE_CFI_PERF |
| #endif |
| #endif |
| |
| // Macro useful for writing cross-platform function pointers. |
| #if !defined(CDECL) |
| #if defined(OS_WIN) |
| #define CDECL __cdecl |
| #else // defined(OS_WIN) |
| #define CDECL |
| #endif // defined(OS_WIN) |
| #endif // !defined(CDECL) |
| |
| // Macro for hinting that an expression is likely to be false. |
| #if !defined(UNLIKELY) |
| #if defined(COMPILER_GCC) || defined(__clang__) |
| #define UNLIKELY(x) __builtin_expect(!!(x), 0) |
| #else |
| #define UNLIKELY(x) (x) |
| #endif // defined(COMPILER_GCC) |
| #endif // !defined(UNLIKELY) |
| |
| #if !defined(LIKELY) |
| #if defined(COMPILER_GCC) || defined(__clang__) |
| #define LIKELY(x) __builtin_expect(!!(x), 1) |
| #else |
| #define LIKELY(x) (x) |
| #endif // defined(COMPILER_GCC) |
| #endif // !defined(LIKELY) |
| |
| // Compiler feature-detection. |
| // clang.llvm.org/docs/LanguageExtensions.html#has-feature-and-has-extension |
| #if defined(__has_feature) |
| #define HAS_FEATURE(FEATURE) __has_feature(FEATURE) |
| #else |
| #define HAS_FEATURE(FEATURE) 0 |
| #endif |
| |
| // Macro for telling -Wimplicit-fallthrough that a fallthrough is intentional. |
| #if defined(__clang__) |
| #define FALLTHROUGH [[clang::fallthrough]] |
| #else |
| #define FALLTHROUGH |
| #endif |
| |
| #endif // THIRD_PARTY_BASE_COMPILER_SPECIFIC_H_ |