diff options
Diffstat (limited to 'security/sandbox/chromium/base/compiler_specific.h')
| -rw-r--r-- | security/sandbox/chromium/base/compiler_specific.h | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/security/sandbox/chromium/base/compiler_specific.h b/security/sandbox/chromium/base/compiler_specific.h new file mode 100644 index 0000000000..5f931c8704 --- /dev/null +++ b/security/sandbox/chromium/base/compiler_specific.h @@ -0,0 +1,298 @@ +// 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 BASE_COMPILER_SPECIFIC_H_ +#define BASE_COMPILER_SPECIFIC_H_ + +#include "build/build_config.h" + +#if defined(COMPILER_MSVC) + +#if !defined(__clang__) +#error "Only clang-cl is supported on Windows, see https://crbug.com/988071" +#endif + +// Macros for suppressing and disabling warnings on MSVC. +// +// Warning numbers are enumerated at: +// http://msdn.microsoft.com/en-us/library/8x5x43k7(VS.80).aspx +// +// The warning pragma: +// http://msdn.microsoft.com/en-us/library/2c8f766e(VS.80).aspx +// +// Using __pragma instead of #pragma inside macros: +// http://msdn.microsoft.com/en-us/library/d9x1s805.aspx + +// MSVC_PUSH_DISABLE_WARNING pushes |n| onto a stack of warnings to be disabled. +// The warning remains disabled until popped by MSVC_POP_WARNING. +#define MSVC_PUSH_DISABLE_WARNING(n) \ + __pragma(warning(push)) __pragma(warning(disable : n)) + +// Pop effects of innermost MSVC_PUSH_* macro. +#define MSVC_POP_WARNING() __pragma(warning(pop)) + +#else // Not MSVC + +#define MSVC_PUSH_DISABLE_WARNING(n) +#define MSVC_POP_WARNING() +#define MSVC_DISABLE_OPTIMIZE() +#define MSVC_ENABLE_OPTIMIZE() + +#endif // COMPILER_MSVC + +// These macros can be helpful when investigating compiler bugs or when +// investigating issues in local optimized builds, by temporarily disabling +// optimizations for a single function or file. These macros should never be +// used to permanently work around compiler bugs or other mysteries, and should +// not be used in landed changes. +#if !defined(OFFICIAL_BUILD) +#if defined(__clang__) +#define DISABLE_OPTIMIZE() __pragma(clang optimize off) +#define ENABLE_OPTIMIZE() __pragma(clang optimize on) +#elif defined(COMPILER_MSVC) +#define DISABLE_OPTIMIZE() __pragma(optimize("", off)) +#define ENABLE_OPTIMIZE() __pragma(optimize("", on)) +#else +// These macros are not currently available for other compiler options. +#endif +// These macros are not available in official builds. +#endif // !defined(OFFICIAL_BUILD) + +// 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.) +// For member functions, the implicit this parameter counts as index 1. +#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 + +#if defined(COMPILER_GCC) +#define PRETTY_FUNCTION __PRETTY_FUNCTION__ +#elif defined(COMPILER_MSVC) +#define PRETTY_FUNCTION __FUNCSIG__ +#else +// See https://en.cppreference.com/w/c/language/function_definition#func +#define PRETTY_FUNCTION __func__ +#endif + +#if !defined(CPU_ARM_NEON) +#if defined(__arm__) +#if !defined(__ARMEB__) && !defined(__ARM_EABI__) && !defined(__EABI__) && \ + !defined(__VFP_FP__) && !defined(_WIN32_WCE) && !defined(ANDROID) +#error Chromium does not support middle endian architecture +#endif +#if defined(__ARM_NEON__) +#define CPU_ARM_NEON 1 +#endif +#endif // defined(__arm__) +#endif // !defined(CPU_ARM_NEON) + +#if !defined(HAVE_MIPS_MSA_INTRINSICS) +#if defined(__mips_msa) && defined(__mips_isa_rev) && (__mips_isa_rev >= 5) +#define HAVE_MIPS_MSA_INTRINSICS 1 +#endif +#endif + +#if defined(__clang__) && __has_attribute(uninitialized) +// Attribute "uninitialized" disables -ftrivial-auto-var-init=pattern for +// the specified variable. +// Library-wide alternative is +// 'configs -= [ "//build/config/compiler:default_init_stack_vars" ]' in .gn +// file. +// +// See "init_stack_vars" in build/config/compiler/BUILD.gn and +// http://crbug.com/977230 +// "init_stack_vars" is enabled for non-official builds and we hope to enable it +// in official build in 2020 as well. The flag writes fixed pattern into +// uninitialized parts of all local variables. In rare cases such initialization +// is undesirable and attribute can be used: +// 1. Degraded performance +// In most cases compiler is able to remove additional stores. E.g. if memory is +// never accessed or properly initialized later. Preserved stores mostly will +// not affect program performance. However if compiler failed on some +// performance critical code we can get a visible regression in a benchmark. +// 2. memset, memcpy calls +// Compiler may replaces some memory writes with memset or memcpy calls. This is +// not -ftrivial-auto-var-init specific, but it can happen more likely with the +// flag. It can be a problem if code is not linked with C run-time library. +// +// Note: The flag is security risk mitigation feature. So in future the +// attribute uses should be avoided when possible. However to enable this +// mitigation on the most of the code we need to be less strict now and minimize +// number of exceptions later. So if in doubt feel free to use attribute, but +// please document the problem for someone who is going to cleanup it later. +// E.g. platform, bot, benchmark or test name in patch description or next to +// the attribute. +#define STACK_UNINITIALIZED __attribute__((uninitialized)) +#else +#define STACK_UNINITIALIZED +#endif + +#endif // BASE_COMPILER_SPECIFIC_H_ |