diff options
Diffstat (limited to 'absl/base/attributes.h')
| -rw-r--r-- | absl/base/attributes.h | 137 |
1 files changed, 99 insertions, 38 deletions
diff --git a/absl/base/attributes.h b/absl/base/attributes.h index ff138629..046fbea3 100644 --- a/absl/base/attributes.h +++ b/absl/base/attributes.h @@ -32,34 +32,12 @@ // of them are not supported in older version of Clang. Thus, we check // `__has_attribute()` first. If the check fails, we check if we are on GCC and // assume the attribute exists on GCC (which is verified on GCC 4.7). -// -// ----------------------------------------------------------------------------- -// Sanitizer Attributes -// ----------------------------------------------------------------------------- -// -// Sanitizer-related attributes are not "defined" in this file (and indeed -// are not defined as such in any file). To utilize the following -// sanitizer-related attributes within your builds, define the following macros -// within your build using a `-D` flag, along with the given value for -// `-fsanitize`: -// -// * `ADDRESS_SANITIZER` + `-fsanitize=address` (Clang, GCC 4.8) -// * `MEMORY_SANITIZER` + `-fsanitize=memory` (Clang-only) -// * `THREAD_SANITIZER + `-fsanitize=thread` (Clang, GCC 4.8+) -// * `UNDEFINED_BEHAVIOR_SANITIZER` + `-fsanitize=undefined` (Clang, GCC 4.9+) -// * `CONTROL_FLOW_INTEGRITY` + -fsanitize=cfi (Clang-only) -// -// Example: -// -// // Enable branches in the Abseil code that are tagged for ASan: -// $ bazel build --copt=-DADDRESS_SANITIZER --copt=-fsanitize=address -// --linkopt=-fsanitize=address *target* -// -// Since these macro names are only supported by GCC and Clang, we only check -// for `__GNUC__` (GCC or Clang) and the above macros. + #ifndef ABSL_BASE_ATTRIBUTES_H_ #define ABSL_BASE_ATTRIBUTES_H_ +#include "absl/base/config.h" + // ABSL_HAVE_ATTRIBUTE // // A function-like feature checking macro that is a wrapper around @@ -234,7 +212,7 @@ // out of bounds or does other scary things with memory. // NOTE: GCC supports AddressSanitizer(asan) since 4.8. // https://gcc.gnu.org/gcc-4.8/changes.html -#if defined(__GNUC__) +#if ABSL_HAVE_ATTRIBUTE(no_sanitize_address) #define ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address)) #else #define ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS @@ -242,13 +220,13 @@ // ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY // -// Tells the MemorySanitizer to relax the handling of a given function. All -// "Use of uninitialized value" warnings from such functions will be suppressed, -// and all values loaded from memory will be considered fully initialized. -// This attribute is similar to the ADDRESS_SANITIZER attribute above, but deals -// with initialized-ness rather than addressability issues. +// Tells the MemorySanitizer to relax the handling of a given function. All "Use +// of uninitialized value" warnings from such functions will be suppressed, and +// all values loaded from memory will be considered fully initialized. This +// attribute is similar to the ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS attribute +// above, but deals with initialized-ness rather than addressability issues. // NOTE: MemorySanitizer(msan) is supported by Clang but not GCC. -#if defined(__clang__) +#if ABSL_HAVE_ATTRIBUTE(no_sanitize_memory) #define ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY __attribute__((no_sanitize_memory)) #else #define ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY @@ -259,7 +237,7 @@ // Tells the ThreadSanitizer to not instrument a given function. // NOTE: GCC supports ThreadSanitizer(tsan) since 4.8. // https://gcc.gnu.org/gcc-4.8/changes.html -#if defined(__GNUC__) +#if ABSL_HAVE_ATTRIBUTE(no_sanitize_thread) #define ABSL_ATTRIBUTE_NO_SANITIZE_THREAD __attribute__((no_sanitize_thread)) #else #define ABSL_ATTRIBUTE_NO_SANITIZE_THREAD @@ -271,8 +249,10 @@ // where certain behavior (eg. division by zero) is being used intentionally. // NOTE: GCC supports UndefinedBehaviorSanitizer(ubsan) since 4.9. // https://gcc.gnu.org/gcc-4.9/changes.html -#if defined(__GNUC__) && \ - (defined(UNDEFINED_BEHAVIOR_SANITIZER) || defined(ADDRESS_SANITIZER)) +#if ABSL_HAVE_ATTRIBUTE(no_sanitize_undefined) +#define ABSL_ATTRIBUTE_NO_SANITIZE_UNDEFINED \ + __attribute__((no_sanitize_undefined)) +#elif ABSL_HAVE_ATTRIBUTE(no_sanitize) #define ABSL_ATTRIBUTE_NO_SANITIZE_UNDEFINED \ __attribute__((no_sanitize("undefined"))) #else @@ -283,7 +263,7 @@ // // Tells the ControlFlowIntegrity sanitizer to not instrument a given function. // See https://clang.llvm.org/docs/ControlFlowIntegrity.html for details. -#if defined(__GNUC__) && defined(CONTROL_FLOW_INTEGRITY) +#if ABSL_HAVE_ATTRIBUTE(no_sanitize) #define ABSL_ATTRIBUTE_NO_SANITIZE_CFI __attribute__((no_sanitize("cfi"))) #else #define ABSL_ATTRIBUTE_NO_SANITIZE_CFI @@ -293,7 +273,7 @@ // // Tells the SafeStack to not instrument a given function. // See https://clang.llvm.org/docs/SafeStack.html for details. -#if defined(__GNUC__) && defined(SAFESTACK_SANITIZER) +#if ABSL_HAVE_ATTRIBUTE(no_sanitize) #define ABSL_ATTRIBUTE_NO_SANITIZE_SAFESTACK \ __attribute__((no_sanitize("safe-stack"))) #else @@ -507,8 +487,10 @@ // packages/targets, as this may lead to conflicting definitions of functions at // link-time. // +// XRay isn't currently supported on Android: +// https://github.com/android/ndk/issues/368 #if ABSL_HAVE_CPP_ATTRIBUTE(clang::xray_always_instrument) && \ - !defined(ABSL_NO_XRAY_ATTRIBUTES) + !defined(ABSL_NO_XRAY_ATTRIBUTES) && !defined(__ANDROID__) #define ABSL_XRAY_ALWAYS_INSTRUMENT [[clang::xray_always_instrument]] #define ABSL_XRAY_NEVER_INSTRUMENT [[clang::xray_never_instrument]] #if ABSL_HAVE_CPP_ATTRIBUTE(clang::xray_log_args) @@ -592,6 +574,85 @@ #define ABSL_ATTRIBUTE_FUNC_ALIGN(bytes) #endif +// ABSL_FALLTHROUGH_INTENDED +// +// Annotates implicit fall-through between switch labels, allowing a case to +// indicate intentional fallthrough and turn off warnings about any lack of a +// `break` statement. The ABSL_FALLTHROUGH_INTENDED macro should be followed by +// a semicolon and can be used in most places where `break` can, provided that +// no statements exist between it and the next switch label. +// +// Example: +// +// switch (x) { +// case 40: +// case 41: +// if (truth_is_out_there) { +// ++x; +// ABSL_FALLTHROUGH_INTENDED; // Use instead of/along with annotations +// // in comments +// } else { +// return x; +// } +// case 42: +// ... +// +// Notes: when compiled with clang in C++11 mode, the ABSL_FALLTHROUGH_INTENDED +// macro is expanded to the [[clang::fallthrough]] attribute, which is analysed +// when performing switch labels fall-through diagnostic +// (`-Wimplicit-fallthrough`). See clang documentation on language extensions +// for details: +// https://clang.llvm.org/docs/AttributeReference.html#fallthrough-clang-fallthrough +// +// When used with unsupported compilers, the ABSL_FALLTHROUGH_INTENDED macro +// has no effect on diagnostics. In any case this macro has no effect on runtime +// behavior and performance of code. +#ifdef ABSL_FALLTHROUGH_INTENDED +#error "ABSL_FALLTHROUGH_INTENDED should not be defined." +#endif + +// TODO(zhangxy): Use c++17 standard [[fallthrough]] macro, when supported. +#if defined(__clang__) && defined(__has_warning) +#if __has_feature(cxx_attributes) && __has_warning("-Wimplicit-fallthrough") +#define ABSL_FALLTHROUGH_INTENDED [[clang::fallthrough]] +#endif +#elif defined(__GNUC__) && __GNUC__ >= 7 +#define ABSL_FALLTHROUGH_INTENDED [[gnu::fallthrough]] +#endif + +#ifndef ABSL_FALLTHROUGH_INTENDED +#define ABSL_FALLTHROUGH_INTENDED \ + do { \ + } while (0) +#endif + +// ABSL_DEPRECATED() +// +// Marks a deprecated class, struct, enum, function, method and variable +// declarations. The macro argument is used as a custom diagnostic message (e.g. +// suggestion of a better alternative). +// +// Examples: +// +// class ABSL_DEPRECATED("Use Bar instead") Foo {...}; +// +// ABSL_DEPRECATED("Use Baz() instead") void Bar() {...} +// +// template <typename T> +// ABSL_DEPRECATED("Use DoThat() instead") +// void DoThis(); +// +// Every usage of a deprecated entity will trigger a warning when compiled with +// clang's `-Wdeprecated-declarations` option. This option is turned off by +// default, but the warnings will be reported by clang-tidy. +#if defined(__clang__) && __cplusplus >= 201103L +#define ABSL_DEPRECATED(message) __attribute__((deprecated(message))) +#endif + +#ifndef ABSL_DEPRECATED +#define ABSL_DEPRECATED(message) +#endif + // ABSL_CONST_INIT // // A variable declaration annotated with the `ABSL_CONST_INIT` attribute will |