// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#ifndef ABSL_DEBUGGING_INTERNAL_ADDRESS_IS_READABLE_H_
#define ABSL_DEBUGGING_INTERNAL_ADDRESS_IS_READABLE_H_
namespace absl {
namespace debug_internal {
// Return whether the byte at *addr is readable, without faulting.
// Save and restores errno.
bool AddressIsReadable(const void* addr);
} // namespace debug_internal
} // namespace absl
#endif // ABSL_DEBUGGING_INTERNAL_ADDRESS_IS_READABLE_H_
/*
* Copyright 2017 The Abseil Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// Allow dynamic symbol lookup for in-memory Elf images.
#ifndef ABSL_DEBUGGING_INTERNAL_ELF_MEM_IMAGE_H_
#define ABSL_DEBUGGING_INTERNAL_ELF_MEM_IMAGE_H_
// Including this will define the __GLIBC__ macro if glibc is being
// used.
#include <climits>
// Maybe one day we can rewrite this file not to require the elf
// symbol extensions in glibc, but for right now we need them.
#ifdef ABSL_HAVE_ELF_MEM_IMAGE
#error ABSL_HAVE_ELF_MEM_IMAGE cannot be directly set
#endif
#if defined(__ELF__) && defined(__GLIBC__) && !defined(__native_client__) && !defined(__asmjs__)
#define ABSL_HAVE_ELF_MEM_IMAGE 1
#endif
#if ABSL_HAVE_ELF_MEM_IMAGE
#include <link.h> // for ElfW
namespace absl {
namespace debug_internal {
// An in-memory ELF image (may not exist on disk).
class ElfMemImage {
public:
// Sentinel: there could never be an elf image at this address.
static const void* const kInvalidBase;
// Information about a single vdso symbol.
// All pointers are into .dynsym, .dynstr, or .text of the VDSO.
// Do not free() them or modify through them.
struct SymbolInfo {
const char* name; // E.g. "__vdso_getcpu"
const char* version; // E.g. "LINUX_2.6", could be ""
// for unversioned symbol.
const void* address; // Relocated symbol address.
const ElfW(Sym) * symbol; // Symbol in the dynamic symbol table.
};
// Supports iteration over all dynamic symbols.
class SymbolIterator {
public:
friend class ElfMemImage;
const SymbolInfo* operator->() const;
const SymbolInfo& operator*() const;
SymbolIterator& operator++();
bool operator!=(const SymbolIterator& rhs) const;
bool operator==(const SymbolIterator& rhs) const;
private:
SymbolIterator(const void* const image, int index);
void Update(int incr);
SymbolInfo info_;
int index_;
const void* const image_;
};
explicit ElfMemImage(const void* base);
void Init(const void* base);
bool IsPresent() const { return ehdr_ != nullptr; }
const ElfW(Phdr) * GetPhdr(int index) const;
const ElfW(Sym) * GetDynsym(int index) const;
const ElfW(Versym) * GetVersym(int index) const;
const ElfW(Verdef) * GetVerdef(int index) const;
const ElfW(Verdaux) * GetVerdefAux(const ElfW(Verdef) * verdef) const;
const char* GetDynstr(ElfW(Word) offset) const;
const void* GetSymAddr(const ElfW(Sym) * sym) const;
const char* GetVerstr(ElfW(Word) offset) const;
int GetNumSymbols() const;
SymbolIterator begin() const;
SymbolIterator end() const;
// Look up versioned dynamic symbol in the image.
// Returns false if image is not present, or doesn't contain given
// symbol/version/type combination.
// If info_out is non-null, additional details are filled in.
bool LookupSymbol(const char* name, const char* version, int symbol_type, SymbolInfo* info_out) const;
// Find info about symbol (if any) which overlaps given address.
// Returns true if symbol was found; false if image isn't present
// or doesn't have a symbol overlapping given address.
// If info_out is non-null, additional details are filled in.
bool LookupSymbolByAddress(const void* address, SymbolInfo* info_out) const;
private:
const ElfW(Ehdr) * ehdr_;
const ElfW(Sym) * dynsym_;
const ElfW(Versym) * versym_;
const ElfW(Verdef) * verdef_;
const ElfW(Word) * hash_;
const char* dynstr_;
size_t strsize_;
size_t verdefnum_;
ElfW(Addr) link_base_; // Link-time base (p_vaddr of first PT_LOAD).
};
} // namespace debug_internal
} // namespace absl
#endif // ABSL_HAVE_ELF_MEM_IMAGE
#endif // ABSL_DEBUGGING_INTERNAL_ELF_MEM_IMAGE_H_
/*
* Copyright 2017 The Abseil Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* Defines ABSL_STACKTRACE_INL_HEADER to the *-inl.h containing
* actual unwinder implementation.
* This header is "private" to stacktrace.cc.
* DO NOT include it into any other files.
*/
#ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_CONFIG_H_
#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_CONFIG_H_
// First, test platforms which only support a stub.
#if ABSL_STACKTRACE_INL_HEADER
#error ABSL_STACKTRACE_INL_HEADER cannot be directly set
#elif defined(__native_client__) || defined(__APPLE__) || defined(__ANDROID__) || defined(__myriad2__) || \
defined(asmjs__) || defined(__Fuchsia__)
#define ABSL_STACKTRACE_INL_HEADER "stacktrace_internal/stacktrace_unimplemented-inl.inc"
// Next, test for Mips and Windows.
// TODO(marmstrong): Mips case, remove the check for ABSL_STACKTRACE_INL_HEADER
#elif defined(__mips__) && !defined(ABSL_STACKTRACE_INL_HEADER)
#define ABSL_STACKTRACE_INL_HEADER "stacktrace_internal/stacktrace_unimplemented-inl.inc"
#elif defined(_WIN32) // windows
#define ABSL_STACKTRACE_INL_HEADER "stacktrace_internal/stacktrace_win32-inl.inc"
// Finally, test NO_FRAME_POINTER.
#elif !defined(NO_FRAME_POINTER)
#if defined(__i386__) || defined(__x86_64__)
#define ABSL_STACKTRACE_INL_HEADER "stacktrace_internal/stacktrace_x86-inl.inc"
#elif defined(__ppc__) || defined(__PPC__)
#define ABSL_STACKTRACE_INL_HEADER "stacktrace_internal/stacktrace_powerpc-inl.inc"
#elif defined(__aarch64__)
#define ABSL_STACKTRACE_INL_HEADER "stacktrace_internal/stacktrace_aarch64-inl.inc"
#elif defined(__arm__)
#define ABSL_STACKTRACE_INL_HEADER "stacktrace_internal/stacktrace_arm-inl.inc"
#endif
#else // defined(NO_FRAME_POINTER)
#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__)
#define ABSL_STACKTRACE_INL_HEADER "stacktrace_internal/stacktrace_unimplemented-inl.inc"
#elif defined(__ppc__) || defined(__PPC__)
// Use glibc's backtrace.
#define ABSL_STACKTRACE_INL_HEADER "stacktrace_internal/stacktrace_generic-inl.inc"
#elif defined(__arm__)
#error stacktrace without frame pointer is not supported on ARM
#endif
#endif // NO_FRAME_POINTER
#if !defined(ABSL_STACKTRACE_INL_HEADER)
#error Not supported yet
#endif
#endif // ABSL_DEBUGGING_INTERNAL_STACKTRACE_CONFIG_H_
//
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Allow dynamic symbol lookup in the kernel VDSO page.
//
// VDSO stands for "Virtual Dynamic Shared Object" -- a page of
// executable code, which looks like a shared library, but doesn't
// necessarily exist anywhere on disk, and which gets mmap()ed into
// every process by kernels which support VDSO, such as 2.6.x for 32-bit
// executables, and 2.6.24 and above for 64-bit executables.
//
// More details could be found here:
// http://www.trilithium.com/johan/2005/08/linux-gate/
//
// VDSOSupport -- a class representing kernel VDSO (if present).
//
// Example usage:
// VDSOSupport vdso;
// VDSOSupport::SymbolInfo info;
// typedef (*FN)(unsigned *, void *, void *);
// FN fn = nullptr;
// if (vdso.LookupSymbol("__vdso_getcpu", "LINUX_2.6", STT_FUNC, &info)) {
// fn = reinterpret_cast<FN>(info.address);
// }
#ifndef ABSL_DEBUGGING_INTERNAL_VDSO_SUPPORT_H_
#define ABSL_DEBUGGING_INTERNAL_VDSO_SUPPORT_H_
#include <atomic>
#ifdef ABSL_HAVE_ELF_MEM_IMAGE
#ifdef ABSL_HAVE_VDSO_SUPPORT
#error ABSL_HAVE_VDSO_SUPPORT cannot be directly set
#else
#define ABSL_HAVE_VDSO_SUPPORT 1
#endif
namespace absl {
namespace debug_internal {
// NOTE: this class may be used from within tcmalloc, and can not
// use any memory allocation routines.
class VDSOSupport {
public:
VDSOSupport();
typedef ElfMemImage::SymbolInfo SymbolInfo;
typedef ElfMemImage::SymbolIterator SymbolIterator;
// On PowerPC64 VDSO symbols can either be of type STT_FUNC or STT_NOTYPE
// depending on how the kernel is built. The kernel is normally built with
// STT_NOTYPE type VDSO symbols. Let's make things simpler first by using a
// compile-time constant.
#ifdef __powerpc64__
enum { kVDSOSymbolType = STT_NOTYPE };
#else
enum { kVDSOSymbolType = STT_FUNC };
#endif
// Answers whether we have a vdso at all.
bool IsPresent() const { return image_.IsPresent(); }
// Allow to iterate over all VDSO symbols.
SymbolIterator begin() const { return image_.begin(); }
SymbolIterator end() const { return image_.end(); }
// Look up versioned dynamic symbol in the kernel VDSO.
// Returns false if VDSO is not present, or doesn't contain given
// symbol/version/type combination.
// If info_out != nullptr, additional details are filled in.
bool LookupSymbol(const char* name, const char* version, int symbol_type, SymbolInfo* info_out) const;
// Find info about symbol (if any) which overlaps given address.
// Returns true if symbol was found; false if VDSO isn't present
// or doesn't have a symbol overlapping given address.
// If info_out != nullptr, additional details are filled in.
bool LookupSymbolByAddress(const void* address, SymbolInfo* info_out) const;
// Used only for testing. Replace real VDSO base with a mock.
// Returns previous value of vdso_base_. After you are done testing,
// you are expected to call SetBase() with previous value, in order to
// reset state to the way it was.
const void* SetBase(const void* s);
// Computes vdso_base_ and returns it. Should be called as early as
// possible; before any thread creation, chroot or setuid.
static const void* Init();
private:
// image_ represents VDSO ELF image in memory.
// image_.ehdr_ == nullptr implies there is no VDSO.
ElfMemImage image_;
// Cached value of auxv AT_SYSINFO_EHDR, computed once.
// This is a tri-state:
// kInvalidBase => value hasn't been determined yet.
// 0 => there is no VDSO.
// else => vma of VDSO Elf{32,64}_Ehdr.
//
// When testing with mock VDSO, low bit is set.
// The low bit is always available because vdso_base_ is
// page-aligned.
static std::atomic<const void*> vdso_base_;
// NOLINT on 'long' because these routines mimic kernel api.
// The 'cache' parameter may be used by some versions of the kernel,
// and should be nullptr or point to a static buffer containing at
// least two 'long's.
static long InitAndGetCPU(unsigned* cpu,
void* cache, // NOLINT 'long'.
void* unused);
static long GetCPUViaSyscall(unsigned* cpu,
void* cache, // NOLINT 'long'.
void* unused);
typedef long (*GetCpuFn)(unsigned* cpu,
void* cache, // NOLINT 'long'.
void* unused);
// This function pointer may point to InitAndGetCPU,
// GetCPUViaSyscall, or __vdso_getcpu at different stages of initialization.
static std::atomic<GetCpuFn> getcpu_fn_;
friend int GetCPU(void); // Needs access to getcpu_fn_.
VDSOSupport(const VDSOSupport&) = delete;
VDSOSupport& operator=(const VDSOSupport&) = delete;
};
// Same as sched_getcpu() on later glibc versions.
// Return current CPU, using (fast) __vdso_getcpu@LINUX_2.6 if present,
// otherwise use syscall(SYS_getcpu,...).
// May return -1 with errno == ENOSYS if the kernel doesn't
// support SYS_getcpu.
int GetCPU();
} // namespace debug_internal
} // namespace absl
#endif // ABSL_HAVE_ELF_MEM_IMAGE
#endif // ABSL_DEBUGGING_INTERNAL_VDSO_SUPPORT_H_
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// This header file defines macros for declaring attributes for functions,
// types, and variables.
//
// These macros are used within Abseil and allow the compiler to optimize, where
// applicable, certain function calls.
//
// This file is used for both C and C++!
//
// Most macros here are exposing GCC or Clang features, and are stubbed out for
// other compilers.
//
// GCC attributes documentation:
// https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Function-Attributes.html
// https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Variable-Attributes.html
// https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Type-Attributes.html
//
// Most attributes in this file are already supported by GCC 4.7. However, some
// 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 -D ADDRESS_SANITIZER -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_
// ABSL_HAVE_ATTRIBUTE
//
// A function-like feature checking macro that is a wrapper around
// `__has_attribute`, which is defined by GCC 5+ and Clang and evaluates to a
// nonzero constant integer if the attribute is supported or 0 if not.
//
// It evaluates to zero if `__has_attribute` is not defined by the compiler.
//
// GCC: https://gcc.gnu.org/gcc-5/changes.html
// Clang: https://clang.llvm.org/docs/LanguageExtensions.html
#ifdef __has_attribute
#define ABSL_HAVE_ATTRIBUTE(x) __has_attribute(x)
#else
#define ABSL_HAVE_ATTRIBUTE(x) 0
#endif
// ABSL_HAVE_CPP_ATTRIBUTE
//
// A function-like feature checking macro that accepts C++11 style attributes.
// It's a wrapper around `__has_cpp_attribute`, defined by ISO C++ SD-6
// (http://en.cppreference.com/w/cpp/experimental/feature_test). If we don't
// find `__has_cpp_attribute`, will evaluate to 0.
#if defined(__cplusplus) && defined(__has_cpp_attribute)
// NOTE: requiring __cplusplus above should not be necessary, but
// works around https://bugs.llvm.org/show_bug.cgi?id=23435.
#define ABSL_HAVE_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
#else
#define ABSL_HAVE_CPP_ATTRIBUTE(x) 0
#endif
// -----------------------------------------------------------------------------
// Function Attributes
// -----------------------------------------------------------------------------
//
// GCC: https://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
// Clang: https://clang.llvm.org/docs/AttributeReference.html
// ABSL_PRINTF_ATTRIBUTE
// ABSL_SCANF_ATTRIBUTE
//
// Tells the compiler to perform `printf` format std::string checking if the
// compiler supports it; see the 'format' attribute in
// <http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Function-Attributes.html>.
//
// Note: As the GCC manual states, "[s]ince non-static C++ methods
// have an implicit 'this' argument, the arguments of such methods
// should be counted from two, not one."
#if ABSL_HAVE_ATTRIBUTE(format) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_PRINTF_ATTRIBUTE(string_index, first_to_check) \
__attribute__((__format__(__printf__, string_index, first_to_check)))
#define ABSL_SCANF_ATTRIBUTE(string_index, first_to_check) \
__attribute__((__format__(__scanf__, string_index, first_to_check)))
#else
#define ABSL_PRINTF_ATTRIBUTE(string_index, first_to_check)
#define ABSL_SCANF_ATTRIBUTE(string_index, first_to_check)
#endif
// ABSL_ATTRIBUTE_ALWAYS_INLINE
// ABSL_ATTRIBUTE_NOINLINE
//
// Forces functions to either inline or not inline. Introduced in gcc 3.1.
#if ABSL_HAVE_ATTRIBUTE(always_inline) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline))
#define ABSL_HAVE_ATTRIBUTE_ALWAYS_INLINE 1
#else
#define ABSL_ATTRIBUTE_ALWAYS_INLINE
#endif
#if ABSL_HAVE_ATTRIBUTE(noinline) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_NOINLINE __attribute__((noinline))
#define ABSL_HAVE_ATTRIBUTE_NOINLINE 1
#else
#define ABSL_ATTRIBUTE_NOINLINE
#endif
// ABSL_ATTRIBUTE_NO_TAIL_CALL
//
// Prevents the compiler from optimizing away stack frames for functions which
// end in a call to another function.
#if ABSL_HAVE_ATTRIBUTE(disable_tail_calls)
#define ABSL_HAVE_ATTRIBUTE_NO_TAIL_CALL 1
#define ABSL_ATTRIBUTE_NO_TAIL_CALL __attribute__((disable_tail_calls))
#elif defined(__GNUC__) && !defined(__clang__)
#define ABSL_HAVE_ATTRIBUTE_NO_TAIL_CALL 1
#define ABSL_ATTRIBUTE_NO_TAIL_CALL __attribute__((optimize("no-optimize-sibling-calls")))
#else
#define ABSL_ATTRIBUTE_NO_TAIL_CALL
#define ABSL_HAVE_ATTRIBUTE_NO_TAIL_CALL 0
#endif
// ABSL_ATTRIBUTE_WEAK
//
// Tags a function as weak for the purposes of compilation and linking.
#if ABSL_HAVE_ATTRIBUTE(weak) || (defined(__GNUC__) && !defined(__clang__))
#undef ABSL_ATTRIBUTE_WEAK
#define ABSL_ATTRIBUTE_WEAK __attribute__((weak))
#define ABSL_HAVE_ATTRIBUTE_WEAK 1
#else
#define ABSL_ATTRIBUTE_WEAK
#define ABSL_HAVE_ATTRIBUTE_WEAK 0
#endif
// ABSL_ATTRIBUTE_NONNULL
//
// Tells the compiler either (a) that a particular function parameter
// should be a non-null pointer, or (b) that all pointer arguments should
// be non-null.
//
// Note: As the GCC manual states, "[s]ince non-static C++ methods
// have an implicit 'this' argument, the arguments of such methods
// should be counted from two, not one."
//
// Args are indexed starting at 1.
//
// For non-static class member functions, the implicit `this` argument
// is arg 1, and the first explicit argument is arg 2. For static class member
// functions, there is no implicit `this`, and the first explicit argument is
// arg 1.
//
// Example:
//
// /* arg_a cannot be null, but arg_b can */
// void Function(void* arg_a, void* arg_b) ABSL_ATTRIBUTE_NONNULL(1);
//
// class C {
// /* arg_a cannot be null, but arg_b can */
// void Method(void* arg_a, void* arg_b) ABSL_ATTRIBUTE_NONNULL(2);
//
// /* arg_a cannot be null, but arg_b can */
// static void StaticMethod(void* arg_a, void* arg_b)
// ABSL_ATTRIBUTE_NONNULL(1);
// };
//
// If no arguments are provided, then all pointer arguments should be non-null.
//
// /* No pointer arguments may be null. */
// void Function(void* arg_a, void* arg_b, int arg_c) ABSL_ATTRIBUTE_NONNULL();
//
// NOTE: The GCC nonnull attribute actually accepts a list of arguments, but
// ABSL_ATTRIBUTE_NONNULL does not.
#if ABSL_HAVE_ATTRIBUTE(nonnull) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_NONNULL(arg_index) __attribute__((nonnull(arg_index)))
#else
#define ABSL_ATTRIBUTE_NONNULL(...)
#endif
// ABSL_ATTRIBUTE_NORETURN
//
// Tells the compiler that a given function never returns.
#if ABSL_HAVE_ATTRIBUTE(noreturn) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_NORETURN __attribute__((noreturn))
#elif defined(_MSC_VER)
#define ABSL_ATTRIBUTE_NORETURN __declspec(noreturn)
#else
#define ABSL_ATTRIBUTE_NORETURN
#endif
// ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS
//
// Tells the AddressSanitizer (or other memory testing tools) to ignore a given
// function. Useful for cases when a function reads random locations on stack,
// calls _exit from a cloned subprocess, deliberately accesses buffer
// 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__) && defined(ADDRESS_SANITIZER)
#define ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
#else
#define ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS
#endif
// 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.
// NOTE: MemorySanitizer(msan) is supported by Clang but not GCC.
#if defined(__GNUC__) && defined(MEMORY_SANITIZER)
#define ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY __attribute__((no_sanitize_memory))
#else
#define ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY
#endif
// ABSL_ATTRIBUTE_NO_SANITIZE_THREAD
//
// 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__) && defined(THREAD_SANITIZER)
#define ABSL_ATTRIBUTE_NO_SANITIZE_THREAD __attribute__((no_sanitize_thread))
#else
#define ABSL_ATTRIBUTE_NO_SANITIZE_THREAD
#endif
// ABSL_ATTRIBUTE_NO_SANITIZE_UNDEFINED
//
// Tells the UndefinedSanitizer to ignore a given function. Useful for cases
// where certain behavior (eg. devision 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))
#define ABSL_ATTRIBUTE_NO_SANITIZE_UNDEFINED __attribute__((no_sanitize("undefined")))
#else
#define ABSL_ATTRIBUTE_NO_SANITIZE_UNDEFINED
#endif
// ABSL_ATTRIBUTE_NO_SANITIZE_CFI
//
// 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)
#define ABSL_ATTRIBUTE_NO_SANITIZE_CFI __attribute__((no_sanitize("cfi")))
#else
#define ABSL_ATTRIBUTE_NO_SANITIZE_CFI
#endif
// ABSL_HAVE_ATTRIBUTE_SECTION
//
// Indicates whether labeled sections are supported. Labeled sections are not
// supported on Darwin/iOS.
#ifdef ABSL_HAVE_ATTRIBUTE_SECTION
#error ABSL_HAVE_ATTRIBUTE_SECTION cannot be directly set
#elif (ABSL_HAVE_ATTRIBUTE(section) || (defined(__GNUC__) && !defined(__clang__))) && !defined(__APPLE__)
#define ABSL_HAVE_ATTRIBUTE_SECTION 1
// ABSL_ATTRIBUTE_SECTION
//
// Tells the compiler/linker to put a given function into a section and define
// `__start_ ## name` and `__stop_ ## name` symbols to bracket the section.
// This functionality is supported by GNU linker. Any function annotated with
// `ABSL_ATTRIBUTE_SECTION` must not be inlined, or it will be placed into
// whatever section its caller is placed into.
//
#ifndef ABSL_ATTRIBUTE_SECTION
#define ABSL_ATTRIBUTE_SECTION(name) __attribute__((section(#name))) __attribute__((noinline))
#endif
// ABSL_ATTRIBUTE_SECTION_VARIABLE
//
// Tells the compiler/linker to put a given variable into a section and define
// `__start_ ## name` and `__stop_ ## name` symbols to bracket the section.
// This functionality is supported by GNU linker.
#ifndef ABSL_ATTRIBUTE_SECTION_VARIABLE
#define ABSL_ATTRIBUTE_SECTION_VARIABLE(name) __attribute__((section(#name)))
#endif
// ABSL_DECLARE_ATTRIBUTE_SECTION_VARS
//
// A weak section declaration to be used as a global declaration
// for ABSL_ATTRIBUTE_SECTION_START|STOP(name) to compile and link
// even without functions with ABSL_ATTRIBUTE_SECTION(name).
// ABSL_DEFINE_ATTRIBUTE_SECTION should be in the exactly one file; it's
// a no-op on ELF but not on Mach-O.
//
#ifndef ABSL_DECLARE_ATTRIBUTE_SECTION_VARS
#define ABSL_DECLARE_ATTRIBUTE_SECTION_VARS(name) \
extern char __start_##name[] ABSL_ATTRIBUTE_WEAK; \
extern char __stop_##name[] ABSL_ATTRIBUTE_WEAK
#endif
#ifndef ABSL_DEFINE_ATTRIBUTE_SECTION_VARS
#define ABSL_INIT_ATTRIBUTE_SECTION_VARS(name)
#define ABSL_DEFINE_ATTRIBUTE_SECTION_VARS(name)
#endif
// ABSL_ATTRIBUTE_SECTION_START
//
// Returns `void*` pointers to start/end of a section of code with
// functions having ABSL_ATTRIBUTE_SECTION(name).
// Returns 0 if no such functions exist.
// One must ABSL_DECLARE_ATTRIBUTE_SECTION_VARS(name) for this to compile and
// link.
//
#define ABSL_ATTRIBUTE_SECTION_START(name) (reinterpret_cast<void*>(__start_##name))
#define ABSL_ATTRIBUTE_SECTION_STOP(name) (reinterpret_cast<void*>(__stop_##name))
#else // !ABSL_HAVE_ATTRIBUTE_SECTION
#define ABSL_HAVE_ATTRIBUTE_SECTION 0
// provide dummy definitions
#define ABSL_ATTRIBUTE_SECTION(name)
#define ABSL_ATTRIBUTE_SECTION_VARIABLE(name)
#define ABSL_INIT_ATTRIBUTE_SECTION_VARS(name)
#define ABSL_DEFINE_ATTRIBUTE_SECTION_VARS(name)
#define ABSL_DECLARE_ATTRIBUTE_SECTION_VARS(name)
#define ABSL_ATTRIBUTE_SECTION_START(name) (reinterpret_cast<void*>(0))
#define ABSL_ATTRIBUTE_SECTION_STOP(name) (reinterpret_cast<void*>(0))
#endif // ABSL_ATTRIBUTE_SECTION
// ABSL_ATTRIBUTE_STACK_ALIGN_FOR_OLD_LIBC
//
// Support for aligning the stack on 32-bit x86.
#if ABSL_HAVE_ATTRIBUTE(force_align_arg_pointer) || (defined(__GNUC__) && !defined(__clang__))
#if defined(__i386__)
#define ABSL_ATTRIBUTE_STACK_ALIGN_FOR_OLD_LIBC __attribute__((force_align_arg_pointer))
#define ABSL_REQUIRE_STACK_ALIGN_TRAMPOLINE (0)
#elif defined(__x86_64__)
#define ABSL_REQUIRE_STACK_ALIGN_TRAMPOLINE (1)
#define ABSL_ATTRIBUTE_STACK_ALIGN_FOR_OLD_LIBC
#else // !__i386__ && !__x86_64
#define ABSL_REQUIRE_STACK_ALIGN_TRAMPOLINE (0)
#define ABSL_ATTRIBUTE_STACK_ALIGN_FOR_OLD_LIBC
#endif // __i386__
#else
#define ABSL_ATTRIBUTE_STACK_ALIGN_FOR_OLD_LIBC
#define ABSL_REQUIRE_STACK_ALIGN_TRAMPOLINE (0)
#endif
// ABSL_MUST_USE_RESULT
//
// Tells the compiler to warn about unused return values for functions declared
// with this macro. The macro must appear as the very first part of a function
// declaration or definition:
//
// Example:
//
// ABSL_MUST_USE_RESULT Sprocket* AllocateSprocket();
//
// This placement has the broadest compatibility with GCC, Clang, and MSVC, with
// both defs and decls, and with GCC-style attributes, MSVC declspec, C++11
// and C++17 attributes.
//
// ABSL_MUST_USE_RESULT allows using cast-to-void to suppress the unused result
// warning. For that, warn_unused_result is used only for clang but not for gcc.
// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66425
//
// Note: past advice was to place the macro after the argument list.
#if ABSL_HAVE_ATTRIBUTE(nodiscard)
#define ABSL_MUST_USE_RESULT [[nodiscard]]
#elif defined(__clang__) && ABSL_HAVE_ATTRIBUTE(warn_unused_result)
#define ABSL_MUST_USE_RESULT __attribute__((warn_unused_result))
#else
#define ABSL_MUST_USE_RESULT
#endif
// ABSL_ATTRIBUTE_HOT, ABSL_ATTRIBUTE_COLD
//
// Tells GCC that a function is hot or cold. GCC can use this information to
// improve static analysis, i.e. a conditional branch to a cold function
// is likely to be not-taken.
// This annotation is used for function declarations.
//
// Example:
//
// int foo() ABSL_ATTRIBUTE_HOT;
#if ABSL_HAVE_ATTRIBUTE(hot) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_HOT __attribute__((hot))
#else
#define ABSL_ATTRIBUTE_HOT
#endif
#if ABSL_HAVE_ATTRIBUTE(cold) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_COLD __attribute__((cold))
#else
#define ABSL_ATTRIBUTE_COLD
#endif
// ABSL_XRAY_ALWAYS_INSTRUMENT, ABSL_XRAY_NEVER_INSTRUMENT, ABSL_XRAY_LOG_ARGS
//
// We define the ABSL_XRAY_ALWAYS_INSTRUMENT and ABSL_XRAY_NEVER_INSTRUMENT
// macro used as an attribute to mark functions that must always or never be
// instrumented by XRay. Currently, this is only supported in Clang/LLVM.
//
// For reference on the LLVM XRay instrumentation, see
// http://llvm.org/docs/XRay.html.
//
// A function with the XRAY_ALWAYS_INSTRUMENT macro attribute in its declaration
// will always get the XRay instrumentation sleds. These sleds may introduce
// some binary size and runtime overhead and must be used sparingly.
//
// These attributes only take effect when the following conditions are met:
//
// * The file/target is built in at least C++11 mode, with a Clang compiler
// that supports XRay attributes.
// * The file/target is built with the -fxray-instrument flag set for the
// Clang/LLVM compiler.
// * The function is defined in the translation unit (the compiler honors the
// attribute in either the definition or the declaration, and must match).
//
// There are cases when, even when building with XRay instrumentation, users
// might want to control specifically which functions are instrumented for a
// particular build using special-case lists provided to the compiler. These
// special case lists are provided to Clang via the
// -fxray-always-instrument=... and -fxray-never-instrument=... flags. The
// attributes in source take precedence over these special-case lists.
//
// To disable the XRay attributes at build-time, users may define
// ABSL_NO_XRAY_ATTRIBUTES. Do NOT define ABSL_NO_XRAY_ATTRIBUTES on specific
// packages/targets, as this may lead to conflicting definitions of functions at
// link-time.
//
#if ABSL_HAVE_CPP_ATTRIBUTE(clang::xray_always_instrument) && !defined(ABSL_NO_XRAY_ATTRIBUTES)
#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)
#define ABSL_XRAY_LOG_ARGS(N) [[clang::xray_always_instrument, clang::xray_log_args(N)]]
#else
#define ABSL_XRAY_LOG_ARGS(N) [[clang::xray_always_instrument]]
#endif
#else
#define ABSL_XRAY_ALWAYS_INSTRUMENT
#define ABSL_XRAY_NEVER_INSTRUMENT
#define ABSL_XRAY_LOG_ARGS(N)
#endif
// -----------------------------------------------------------------------------
// Variable Attributes
// -----------------------------------------------------------------------------
// ABSL_ATTRIBUTE_UNUSED
//
// Prevents the compiler from complaining about or optimizing away variables
// that appear unused.
#if ABSL_HAVE_ATTRIBUTE(unused) || (defined(__GNUC__) && !defined(__clang__))
#undef ABSL_ATTRIBUTE_UNUSED
#define ABSL_ATTRIBUTE_UNUSED __attribute__((__unused__))
#else
#define ABSL_ATTRIBUTE_UNUSED
#endif
// ABSL_ATTRIBUTE_INITIAL_EXEC
//
// Tells the compiler to use "initial-exec" mode for a thread-local variable.
// See http://people.redhat.com/drepper/tls.pdf for the gory details.
#if ABSL_HAVE_ATTRIBUTE(tls_model) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_INITIAL_EXEC __attribute__((tls_model("initial-exec")))
#else
#define ABSL_ATTRIBUTE_INITIAL_EXEC
#endif
// ABSL_ATTRIBUTE_PACKED
//
// Prevents the compiler from padding a structure to natural alignment
#if ABSL_HAVE_ATTRIBUTE(packed) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_ATTRIBUTE_PACKED __attribute__((__packed__))
#else
#define ABSL_ATTRIBUTE_PACKED
#endif
// ABSL_CONST_INIT
//
// A variable declaration annotated with the `ABSL_CONST_INIT` attribute will
// not compile (on supported platforms) unless the variable has a constant
// initializer. This is useful for variables with static and thread storage
// duration, because it guarantees that they will not suffer from the so-called
// "static init order fiasco".
//
// Example:
//
// ABSL_CONST_INIT static MyType my_var = MakeMyType(...);
//
// Note that this attribute is redundant if the variable is declared constexpr.
#if ABSL_HAVE_CPP_ATTRIBUTE(clang::require_constant_initialization)
// NOLINTNEXTLINE(whitespace/braces)
#define ABSL_CONST_INIT [[clang::require_constant_initialization]]
#else
#define ABSL_CONST_INIT
#endif // ABSL_HAVE_CPP_ATTRIBUTE(clang::require_constant_initialization)
#endif // ABSL_BASE_ATTRIBUTES_H_
//
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// -----------------------------------------------------------------------------
// File: config.h
// -----------------------------------------------------------------------------
//
// This header file defines a set of macros for checking the presence of
// important compiler and platform features. Such macros can be used to
// produce portable code by parameterizing compilation based on the presence or
// lack of a given feature.
//
// We define a "feature" as some interface we wish to program to: for example,
// a library function or system call. A value of `1` indicates support for
// that feature; any other value indicates the feature support is undefined.
//
// Example:
//
// Suppose a programmer wants to write a program that uses the 'mmap()' system
// call. The Abseil macro for that feature (`ABSL_HAVE_MMAP`) allows you to
// selectively include the `mmap.h` header and bracket code using that feature
// in the macro:
//
//
// #ifdef ABSL_HAVE_MMAP
// #include "sys/mman.h"
// #endif //ABSL_HAVE_MMAP
//
// ...
// #ifdef ABSL_HAVE_MMAP
// void *ptr = mmap(...);
// ...
// #endif // ABSL_HAVE_MMAP
#ifndef ABSL_BASE_CONFIG_H_
#define ABSL_BASE_CONFIG_H_
// Included for the __GLIBC__ macro (or similar macros on other systems).
#include <limits.h>
#ifdef __cplusplus
// Included for __GLIBCXX__, _LIBCPP_VERSION
#include <cstddef>
#endif // __cplusplus
#if defined(__APPLE__)
// Included for TARGET_OS_IPHONE, __IPHONE_OS_VERSION_MIN_REQUIRED,
// __IPHONE_8_0.
#include <Availability.h>
#include <TargetConditionals.h>
#endif
// -----------------------------------------------------------------------------
// Compiler Feature Checks
// -----------------------------------------------------------------------------
// ABSL_HAVE_BUILTIN()
//
// Checks whether the compiler supports a Clang Feature Checking Macro, and if
// so, checks whether it supports the provided builtin function "x" where x
// is one of the functions noted in
// https://clang.llvm.org/docs/LanguageExtensions.html
//
// Note: Use this macro to avoid an extra level of #ifdef __has_builtin check.
// http://releases.llvm.org/3.3/tools/clang/docs/LanguageExtensions.html
#ifdef __has_builtin
#define ABSL_HAVE_BUILTIN(x) __has_builtin(x)
#else
#define ABSL_HAVE_BUILTIN(x) 0
#endif
// ABSL_HAVE_TLS is defined to 1 when __thread should be supported.
// We assume __thread is supported on Linux when compiled with Clang or compiled
// against libstdc++ with _GLIBCXX_HAVE_TLS defined.
#ifdef ABSL_HAVE_TLS
#error ABSL_HAVE_TLS cannot be directly set
#elif defined(__linux__) && (defined(__clang__) || defined(_GLIBCXX_HAVE_TLS))
#define ABSL_HAVE_TLS 1
#endif
// There are platforms for which TLS should not be used even though the compiler
// makes it seem like it's supported (Android NDK < r12b for example).
// This is primarily because of linker problems and toolchain misconfiguration:
// Abseil does not intend to support this indefinitely. Currently, the newest
// toolchain that we intend to support that requires this behavior is the
// r11 NDK - allowing for a 5 year support window on that means this option
// is likely to be removed around June of 2021.
#if defined(__ANDROID__) && defined(__clang__)
#if __has_include(<android/ndk-version.h>)
#include <android/ndk-version.h>
#endif
// TLS isn't supported until NDK r12b per
// https://developer.android.com/ndk/downloads/revision_history.html
// Since NDK r16, `__NDK_MAJOR__` and `__NDK_MINOR__` are defined in
// <android/ndk-version.h>. For NDK < r16, users should define these macros,
// e.g. `-D__NDK_MAJOR__=11 -D__NKD_MINOR__=0` for NDK r11.
#if defined(__NDK_MAJOR__) && defined(__NDK_MINOR__) && \
((__NDK_MAJOR__ < 12) || ((__NDK_MAJOR__ == 12) && (__NDK_MINOR__ < 1)))
#undef ABSL_HAVE_TLS
#endif
#endif // defined(__ANDROID__) && defined(__clang__)
// ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE
//
// Checks whether `std::is_trivially_destructible<T>` is supported.
//
// Notes: All supported compilers using libc++ support this feature, as does
// gcc >= 4.8.1 using libstdc++, and Visual Studio.
#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE
#error ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE cannot be directly set
#elif defined(_LIBCPP_VERSION) || \
(!defined(__clang__) && defined(__GNUC__) && defined(__GLIBCXX__) && \
(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))) || \
defined(_MSC_VER)
#define ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE 1
#endif
// ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE
//
// Checks whether `std::is_trivially_default_constructible<T>` and
// `std::is_trivially_copy_constructible<T>` are supported.
// ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE
//
// Checks whether `std::is_trivially_copy_assignable<T>` is supported.
// Notes: Clang with libc++ supports these features, as does gcc >= 5.1 with
// either libc++ or libstdc++, and Visual Studio.
#if defined(ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE)
#error ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE cannot be directly set
#elif defined(ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE)
#error ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE cannot directly set
#elif (defined(__clang__) && defined(_LIBCPP_VERSION)) || \
(!defined(__clang__) && defined(__GNUC__) && (__GNUC__ > 5 || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)) && \
(defined(_LIBCPP_VERSION) || defined(__GLIBCXX__))) || \
defined(_MSC_VER)
#define ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE 1
#define ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE 1
#endif
// ABSL_HAVE_THREAD_LOCAL
//
// Checks whether C++11's `thread_local` storage duration specifier is
// supported.
#ifdef ABSL_HAVE_THREAD_LOCAL
#error ABSL_HAVE_THREAD_LOCAL cannot be directly set
#elif !defined(__apple_build_version__) || \
((__apple_build_version__ >= 8000042) && !(TARGET_OS_IPHONE && __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_9_0))
// Notes: Xcode's clang did not support `thread_local` until version
// 8, and even then not for all iOS < 9.0.
#define ABSL_HAVE_THREAD_LOCAL 1
#endif
// ABSL_HAVE_INTRINSIC_INT128
//
// Checks whether the __int128 compiler extension for a 128-bit integral type is
// supported.
//
// Notes: __SIZEOF_INT128__ is defined by Clang and GCC when __int128 is
// supported, except on ppc64 and aarch64 where __int128 exists but has exhibits
// a sporadic compiler crashing bug. Nvidia's nvcc also defines __GNUC__ and
// __SIZEOF_INT128__ but not all versions actually support __int128.
#ifdef ABSL_HAVE_INTRINSIC_INT128
#error ABSL_HAVE_INTRINSIC_INT128 cannot be directly set
#elif (defined(__clang__) && defined(__SIZEOF_INT128__) && !defined(__ppc64__) && !defined(__aarch64__)) || \
(defined(__CUDACC__) && defined(__SIZEOF_INT128__) && __CUDACC_VER__ >= 70000) || \
(!defined(__clang__) && !defined(__CUDACC__) && defined(__GNUC__) && defined(__SIZEOF_INT128__))
#define ABSL_HAVE_INTRINSIC_INT128 1
#endif
// ABSL_HAVE_EXCEPTIONS
//
// Checks whether the compiler both supports and enables exceptions. Many
// compilers support a "no exceptions" mode that disables exceptions.
//
// Generally, when ABSL_HAVE_EXCEPTIONS is not defined:
//
// * Code using `throw` and `try` may not compile.
// * The `noexcept` specifier will still compile and behave as normal.
// * The `noexcept` operator may still return `false`.
//
// For further details, consult the compiler's documentation.
#ifdef ABSL_HAVE_EXCEPTIONS
#error ABSL_HAVE_EXCEPTIONS cannot be directly set.
#elif defined(__clang__)
// TODO(calabrese)
// Switch to using __cpp_exceptions when we no longer support versions < 3.6.
// For details on this check, see:
// http://releases.llvm.org/3.6.0/tools/clang/docs/ReleaseNotes.html#the-exceptions-macro
#if defined(__EXCEPTIONS) && __has_feature(cxx_exceptions)
#define ABSL_HAVE_EXCEPTIONS 1
#endif // defined(__EXCEPTIONS) && __has_feature(cxx_exceptions)
// Handle remaining special cases and default to exceptions being supported.
#elif !(defined(__GNUC__) && (__GNUC__ < 5) && !defined(__EXCEPTIONS)) && \
!(defined(__GNUC__) && (__GNUC__ >= 5) && !defined(__cpp_exceptions)) && \
!(defined(_MSC_VER) && !defined(_CPPUNWIND))
#define ABSL_HAVE_EXCEPTIONS 1
#endif
// -----------------------------------------------------------------------------
// Platform Feature Checks
// -----------------------------------------------------------------------------
// Currently supported operating systems and associated preprocessor
// symbols:
//
// Linux and Linux-derived __linux__
// Android __ANDROID__ (implies __linux__)
// Linux (non-Android) __linux__ && !__ANDROID__
// Darwin (Mac OS X and iOS) __APPLE__
// Akaros (http://akaros.org) __ros__
// Windows _WIN32
// NaCL __native_client__
// AsmJS __asmjs__
// Fuschia __Fuchsia__
//
// Note that since Android defines both __ANDROID__ and __linux__, one
// may probe for either Linux or Android by simply testing for __linux__.
// ABSL_HAVE_MMAP
//
// Checks whether the platform has an mmap(2) implementation as defined in
// POSIX.1-2001.
#ifdef ABSL_HAVE_MMAP
#error ABSL_HAVE_MMAP cannot be directly set
#elif defined(__linux__) || defined(__APPLE__) || defined(__ros__) || defined(__native_client__) || \
defined(__asmjs__) || defined(__Fuchsia__)
#define ABSL_HAVE_MMAP 1
#endif
// ABSL_HAVE_PTHREAD_GETSCHEDPARAM
//
// Checks whether the platform implements the pthread_(get|set)schedparam(3)
// functions as defined in POSIX.1-2001.
#ifdef ABSL_HAVE_PTHREAD_GETSCHEDPARAM
#error ABSL_HAVE_PTHREAD_GETSCHEDPARAM cannot be directly set
#elif defined(__linux__) || defined(__APPLE__) || defined(__ros__)
#define ABSL_HAVE_PTHREAD_GETSCHEDPARAM 1
#endif
// ABSL_HAVE_SCHED_YIELD
//
// Checks whether the platform implements sched_yield(2) as defined in
// POSIX.1-2001.
#ifdef ABSL_HAVE_SCHED_YIELD
#error ABSL_HAVE_SCHED_YIELD cannot be directly set
#elif defined(__linux__) || defined(__ros__) || defined(__native_client__)
#define ABSL_HAVE_SCHED_YIELD 1
#endif
// ABSL_HAVE_SEMAPHORE_H
//
// Checks whether the platform supports the <semaphore.h> header and sem_open(3)
// family of functions as standardized in POSIX.1-2001.
//
// Note: While Apple provides <semaphore.h> for both iOS and macOS, it is
// explicitly deprecated and will cause build failures if enabled for those
// platforms. We side-step the issue by not defining it here for Apple
// platforms.
#ifdef ABSL_HAVE_SEMAPHORE_H
#error ABSL_HAVE_SEMAPHORE_H cannot be directly set
#elif defined(__linux__) || defined(__ros__)
#define ABSL_HAVE_SEMAPHORE_H 1
#endif
// ABSL_HAVE_ALARM
//
// Checks whether the platform supports the <signal.h> header and alarm(2)
// function as standardized in POSIX.1-2001.
#ifdef ABSL_HAVE_ALARM
#error ABSL_HAVE_ALARM cannot be directly set
#elif defined(__GOOGLE_GRTE_VERSION__)
// feature tests for Google's GRTE
#define ABSL_HAVE_ALARM 1
#elif defined(__GLIBC__)
// feature test for glibc
#define ABSL_HAVE_ALARM 1
#elif defined(_MSC_VER)
// feature tests for Microsoft's library
#elif defined(__native_client__)
#else
// other standard libraries
#define ABSL_HAVE_ALARM 1
#endif
// ABSL_IS_LITTLE_ENDIAN
// ABSL_IS_BIG_ENDIAN
//
// Checks the endianness of the platform.
//
// Notes: uses the built in endian macros provided by GCC (since 4.6) and
// Clang (since 3.2); see
// https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html.
// Otherwise, if _WIN32, assume little endian. Otherwise, bail with an error.
#if defined(ABSL_IS_BIG_ENDIAN)
#error "ABSL_IS_BIG_ENDIAN cannot be directly set."
#endif
#if defined(ABSL_IS_LITTLE_ENDIAN)
#error "ABSL_IS_LITTLE_ENDIAN cannot be directly set."
#endif
#if (defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
#define ABSL_IS_LITTLE_ENDIAN 1
#elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define ABSL_IS_BIG_ENDIAN 1
#elif defined(_WIN32)
#define ABSL_IS_LITTLE_ENDIAN 1
#else
#error "absl endian detection needs to be set up for your compiler"
#endif
// ABSL_HAVE_STD_ANY
//
// Checks whether C++17 std::any is available by checking whether <any> exists.
#ifdef ABSL_HAVE_STD_ANY
#error "ABSL_HAVE_STD_ANY cannot be directly set."
#endif
#ifdef __has_include
#if __has_include(<any>) && __cplusplus >= 201703L
#define ABSL_HAVE_STD_ANY 1
#endif
#endif
// ABSL_HAVE_STD_OPTIONAL
//
// Checks whether C++17 std::optional is available.
#ifdef ABSL_HAVE_STD_OPTIONAL
#error "ABSL_HAVE_STD_OPTIONAL cannot be directly set."
#endif
#ifdef __has_include
#if __has_include(<optional>) && __cplusplus >= 201703L
#define ABSL_HAVE_STD_OPTIONAL 1
#endif
#endif
// ABSL_HAVE_STD_STRING_VIEW
//
// Checks whether C++17 std::string_view is available.
#ifdef ABSL_HAVE_STD_STRING_VIEW
#error "ABSL_HAVE_STD_STRING_VIEW cannot be directly set."
#endif
#ifdef __has_include
#if __has_include(<string_view>) && __cplusplus >= 201703L
#define ABSL_HAVE_STD_STRING_VIEW 1
#endif
#endif
#endif // ABSL_BASE_CONFIG_H_
//
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// -----------------------------------------------------------------------------
// File: optimization.h
// -----------------------------------------------------------------------------
//
// This header file defines portable macros for performance optimization.
#ifndef ABSL_BASE_OPTIMIZATION_H_
#define ABSL_BASE_OPTIMIZATION_H_
// ABSL_BLOCK_TAIL_CALL_OPTIMIZATION
//
// Instructs the compiler to avoid optimizing tail-call recursion. Use of this
// macro is useful when you wish to preserve the existing function order within
// a stack trace for logging, debugging, or profiling purposes.
//
// Example:
//
// int f() {
// int result = g();
// ABSL_BLOCK_TAIL_CALL_OPTIMIZATION();
// return result;
// }
#if defined(__pnacl__)
#define ABSL_BLOCK_TAIL_CALL_OPTIMIZATION() \
if (volatile int x = 0) { \
(void)x; \
}
#elif defined(__clang__)
// Clang will not tail call given inline volatile assembly.
#define ABSL_BLOCK_TAIL_CALL_OPTIMIZATION() __asm__ __volatile__("")
#elif defined(__GNUC__)
// GCC will not tail call given inline volatile assembly.
#define ABSL_BLOCK_TAIL_CALL_OPTIMIZATION() __asm__ __volatile__("")
#elif defined(_MSC_VER)
#include <intrin.h>
// The __nop() intrinsic blocks the optimisation.
#define ABSL_BLOCK_TAIL_CALL_OPTIMIZATION() __nop()
#else
#define ABSL_BLOCK_TAIL_CALL_OPTIMIZATION() \
if (volatile int x = 0) { \
(void)x; \
}
#endif
// ABSL_CACHELINE_SIZE
//
// Explicitly defines the size of the L1 cache for purposes of alignment.
// Setting the cacheline size allows you to specify that certain objects be
// aligned on a cacheline boundary with `ABSL_CACHELINE_ALIGNED` declarations.
// (See below.)
//
// NOTE: this macro should be replaced with the following C++17 features, when
// those are generally available:
//
// * `std::hardware_constructive_interference_size`
// * `std::hardware_destructive_interference_size`
//
// See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0154r1.html
// for more information.
#if defined(__GNUC__)
// Cache line alignment
#if defined(__i386__) || defined(__x86_64__)
#define ABSL_CACHELINE_SIZE 64
#elif defined(__powerpc64__)
#define ABSL_CACHELINE_SIZE 128
#elif defined(__aarch64__)
// We would need to read special register ctr_el0 to find out L1 dcache size.
// This value is a good estimate based on a real aarch64 machine.
#define ABSL_CACHELINE_SIZE 64
#elif defined(__arm__)
// Cache line sizes for ARM: These values are not strictly correct since
// cache line sizes depend on implementations, not architectures. There
// are even implementations with cache line sizes configurable at boot
// time.
#if defined(__ARM_ARCH_5T__)
#define ABSL_CACHELINE_SIZE 32
#elif defined(__ARM_ARCH_7A__)
#define ABSL_CACHELINE_SIZE 64
#endif
#endif
#ifndef ABSL_CACHELINE_SIZE
// A reasonable default guess. Note that overestimates tend to waste more
// space, while underestimates tend to waste more time.
#define ABSL_CACHELINE_SIZE 64
#endif
// ABSL_CACHELINE_ALIGNED
//
// Indicates that the declared object be cache aligned using
// `ABSL_CACHELINE_SIZE` (see above). Cacheline aligning objects allows you to
// load a set of related objects in the L1 cache for performance improvements.
// Cacheline aligning objects properly allows constructive memory sharing and
// prevents destructive (or "false") memory sharing.
//
// NOTE: this macro should be replaced with usage of `alignas()` using
// `std::hardware_constructive_interference_size` and/or
// `std::hardware_destructive_interference_size` when available within C++17.
//
// See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0154r1.html
// for more information.
//
// On some compilers, `ABSL_CACHELINE_ALIGNED` expands to
// `__attribute__((aligned(ABSL_CACHELINE_SIZE)))`. For compilers where this is
// not known to work, the macro expands to nothing.
//
// No further guarantees are made here. The result of applying the macro
// to variables and types is always implementation-defined.
//
// WARNING: It is easy to use this attribute incorrectly, even to the point
// of causing bugs that are difficult to diagnose, crash, etc. It does not
// of itself guarantee that objects are aligned to a cache line.
//
// Recommendations:
//
// 1) Consult compiler documentation; this comment is not kept in sync as
// toolchains evolve.
// 2) Verify your use has the intended effect. This often requires inspecting
// the generated machine code.
// 3) Prefer applying this attribute to individual variables. Avoid
// applying it to types. This tends to localize the effect.
#define ABSL_CACHELINE_ALIGNED __attribute__((aligned(ABSL_CACHELINE_SIZE)))
#else // not GCC
#define ABSL_CACHELINE_SIZE 64
#define ABSL_CACHELINE_ALIGNED
#endif
// ABSL_PREDICT_TRUE, ABSL_PREDICT_FALSE
//
// Enables the compiler to prioritize compilation using static analysis for
// likely paths within a boolean branch.
//
// Example:
//
// if (ABSL_PREDICT_TRUE(expression)) {
// return result; // Faster if more likely
// } else {
// return 0;
// }
//
// Compilers can use the information that a certain branch is not likely to be
// taken (for instance, a CHECK failure) to optimize for the common case in
// the absence of better information (ie. compiling gcc with `-fprofile-arcs`).
#if ABSL_HAVE_BUILTIN(__builtin_expect) || (defined(__GNUC__) && !defined(__clang__))
#define ABSL_PREDICT_FALSE(x) (__builtin_expect(x, 0))
#define ABSL_PREDICT_TRUE(x) (__builtin_expect(!!(x), 1))
#else
#define ABSL_PREDICT_FALSE(x) x
#define ABSL_PREDICT_TRUE(x) x
#endif
#endif // ABSL_BASE_OPTIMIZATION_H_
//
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// -----------------------------------------------------------------------------
// File: macros.h
// -----------------------------------------------------------------------------
//
// This header file defines the set of language macros used within Abseil code.
// For the set of macros used to determine supported compilers and platforms,
// see absl/base/config.h instead.
//
// This code is compiled directly on many platforms, including client
// platforms like Windows, Mac, and embedded systems. Before making
// any changes here, make sure that you're not breaking any platforms.
//
#ifndef ABSL_BASE_MACROS_H_
#define ABSL_BASE_MACROS_H_
#include <cstddef>
// ABSL_ARRAYSIZE()
//
// Returns the # of elements in an array as a compile-time constant, which can
// be used in defining new arrays. If you use this macro on a pointer by
// mistake, you will get a compile-time error.
//
// Note: this template function declaration is used in defining arraysize.
// Note that the function doesn't need an implementation, as we only
// use its type.
namespace absl {
namespace macros_internal {
template <typename T, size_t N>
char (&ArraySizeHelper(T (&array)[N]))[N];
} // namespace macros_internal
} // namespace absl
#define ABSL_ARRAYSIZE(array) (sizeof(::absl::macros_internal::ArraySizeHelper(array)))
// kLinkerInitialized
//
// An enum used only as a constructor argument to indicate that a variable has
// static storage duration, and that the constructor should do nothing to its
// state. Use of this macro indicates to the reader that it is legal to
// declare a static instance of the class, provided the constructor is given
// the absl::base_internal::kLinkerInitialized argument.
//
// Normally, it is unsafe to declare a static variable that has a constructor or
// a destructor because invocation order is undefined. However, if the type can
// be zero-initialized (which the loader does for static variables) into a valid
// state and the type's destructor does not affect storage, then a constructor
// for static initialization can be declared.
//
// Example:
// // Declaration
// explicit MyClass(absl::base_internal:LinkerInitialized x) {}
//
// // Invocation
// static MyClass my_global(absl::base_internal::kLinkerInitialized);
namespace absl {
namespace base_internal {
enum LinkerInitialized {
kLinkerInitialized = 0,
};
} // namespace base_internal
} // namespace absl
// 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:
// http://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).
//
// Example:
//
// class ABSL_DEPRECATED("Use Bar instead") Foo {...};
// ABSL_DEPRECATED("Use Baz instead") void Bar() {...}
//
// 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 && defined(__has_warning)
#define ABSL_DEPRECATED(message) __attribute__((deprecated(message)))
#endif
#ifndef ABSL_DEPRECATED
#define ABSL_DEPRECATED(message)
#endif
// ABSL_BAD_CALL_IF()
//
// Used on a function overload to trap bad calls: any call that matches the
// overload will cause a compile-time error. This macro uses a clang-specific
// "enable_if" attribute, as described at
// http://clang.llvm.org/docs/AttributeReference.html#enable-if
//
// Overloads which use this macro should be bracketed by
// `#ifdef ABSL_BAD_CALL_IF`.
//
// Example:
//
// int isdigit(int c);
// #ifdef ABSL_BAD_CALL_IF
// int isdigit(int c)
// ABSL_BAD_CALL_IF(c <= -1 || c > 255,
// "'c' must have the value of an unsigned char or EOF");
// #endif // ABSL_BAD_CALL_IF
#if defined(__clang__)
#if __has_attribute(enable_if)
#define ABSL_BAD_CALL_IF(expr, msg) __attribute__((enable_if(expr, "Bad call trap"), unavailable(msg)))
#endif
#endif
// ABSL_ASSERT()
//
// In C++11, `assert` can't be used portably within constexpr functions.
// ABSL_ASSERT functions as a runtime assert but works in C++11 constexpr
// functions. Example:
//
// constexpr double Divide(double a, double b) {
// return ABSL_ASSERT(b != 0), a / b;
// }
//
// This macro is inspired by
// https://akrzemi1.wordpress.com/2017/05/18/asserts-in-constexpr-functions/
#if defined(NDEBUG)
#define ABSL_ASSERT(expr) (false ? (void)(expr) : (void)0)
#else
#define ABSL_ASSERT(expr) (ABSL_PREDICT_TRUE((expr)) ? (void)0 : [] { assert(false && #expr); }())
#endif
#endif // ABSL_BASE_MACROS_H_
/*
* Copyright 2017 The Abseil Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* This file defines dynamic annotations for use with dynamic analysis
tool such as valgrind, PIN, etc.
Dynamic annotation is a source code annotation that affects
the generated code (that is, the annotation is not a comment).
Each such annotation is attached to a particular
instruction and/or to a particular object (address) in the program.
The annotations that should be used by users are macros in all upper-case
(e.g., ANNOTATE_THREAD_NAME).
Actual implementation of these macros may differ depending on the
dynamic analysis tool being used.
This file supports the following configurations:
- Dynamic Annotations enabled (with static thread-safety warnings disabled).
In this case, macros expand to functions implemented by Thread Sanitizer,
when building with TSan. When not provided an external implementation,
dynamic_annotations.cc provides no-op implementations.
- Static Clang thread-safety warnings enabled.
When building with a Clang compiler that supports thread-safety warnings,
a subset of annotations can be statically-checked at compile-time. We
expand these macros to static-inline functions that can be analyzed for
thread-safety, but afterwards elided when building the final binary.
- All annotations are disabled.
If neither Dynamic Annotations nor Clang thread-safety warnings are
enabled, then all annotation-macros expand to empty. */
#ifndef ABSL_BASE_DYNAMIC_ANNOTATIONS_H_
#define ABSL_BASE_DYNAMIC_ANNOTATIONS_H_
#ifndef DYNAMIC_ANNOTATIONS_ENABLED
#define DYNAMIC_ANNOTATIONS_ENABLED 0
#endif
#if defined(__native_client__)
#include "nacl/dynamic_annotations.h"
// Stub out the macros missing from the NaCl version.
#ifndef ANNOTATE_CONTIGUOUS_CONTAINER
#define ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid)
#endif
#ifndef ANNOTATE_RWLOCK_CREATE_STATIC
#define ANNOTATE_RWLOCK_CREATE_STATIC(lock)
#endif
#ifndef ADDRESS_SANITIZER_REDZONE
#define ADDRESS_SANITIZER_REDZONE(name)
#endif
#ifndef ANNOTATE_MEMORY_IS_UNINITIALIZED
#define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size)
#endif
#else /* !__native_client__ */
#if DYNAMIC_ANNOTATIONS_ENABLED != 0
/* -------------------------------------------------------------
Annotations that suppress errors. It is usually better to express the
program's synchronization using the other annotations, but these can
be used when all else fails. */
/* Report that we may have a benign race at "pointer", with size
"sizeof(*(pointer))". "pointer" must be a non-void* pointer. Insert at the
point where "pointer" has been allocated, preferably close to the point
where the race happens. See also ANNOTATE_BENIGN_RACE_STATIC. */
#define ANNOTATE_BENIGN_RACE(pointer, description) \
AnnotateBenignRaceSized(__FILE__, __LINE__, pointer, sizeof(*(pointer)), description)
/* Same as ANNOTATE_BENIGN_RACE(address, description), but applies to
the memory range [address, address+size). */
#define ANNOTATE_BENIGN_RACE_SIZED(address, size, description) \
AnnotateBenignRaceSized(__FILE__, __LINE__, address, size, description)
/* Enable (enable!=0) or disable (enable==0) race detection for all threads.
This annotation could be useful if you want to skip expensive race analysis
during some period of program execution, e.g. during initialization. */
#define ANNOTATE_ENABLE_RACE_DETECTION(enable) AnnotateEnableRaceDetection(__FILE__, __LINE__, enable)
/* -------------------------------------------------------------
Annotations useful for debugging. */
/* Report the current thread name to a race detector. */
#define ANNOTATE_THREAD_NAME(name) AnnotateThreadName(__FILE__, __LINE__, name)
/* -------------------------------------------------------------
Annotations useful when implementing locks. They are not
normally needed by modules that merely use locks.
The "lock" argument is a pointer to the lock object. */
/* Report that a lock has been created at address "lock". */
#define ANNOTATE_RWLOCK_CREATE(lock) AnnotateRWLockCreate(__FILE__, __LINE__, lock)
/* Report that a linker initialized lock has been created at address "lock".
*/
#ifdef THREAD_SANITIZER
#define ANNOTATE_RWLOCK_CREATE_STATIC(lock) AnnotateRWLockCreateStatic(__FILE__, __LINE__, lock)
#else
#define ANNOTATE_RWLOCK_CREATE_STATIC(lock) ANNOTATE_RWLOCK_CREATE(lock)
#endif
/* Report that the lock at address "lock" is about to be destroyed. */
#define ANNOTATE_RWLOCK_DESTROY(lock) AnnotateRWLockDestroy(__FILE__, __LINE__, lock)
/* Report that the lock at address "lock" has been acquired.
is_w=1 for writer lock, is_w=0 for reader lock. */
#define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) AnnotateRWLockAcquired(__FILE__, __LINE__, lock, is_w)
/* Report that the lock at address "lock" is about to be released. */
#define ANNOTATE_RWLOCK_RELEASED(lock, is_w) AnnotateRWLockReleased(__FILE__, __LINE__, lock, is_w)
#else /* DYNAMIC_ANNOTATIONS_ENABLED == 0 */
#define ANNOTATE_RWLOCK_CREATE(lock) /* empty */
#define ANNOTATE_RWLOCK_CREATE_STATIC(lock) /* empty */
#define ANNOTATE_RWLOCK_DESTROY(lock) /* empty */
#define ANNOTATE_RWLOCK_ACQUIRED(lock, is_w) /* empty */
#define ANNOTATE_RWLOCK_RELEASED(lock, is_w) /* empty */
#define ANNOTATE_BENIGN_RACE(address, description) /* empty */
#define ANNOTATE_BENIGN_RACE_SIZED(address, size, description) /* empty */
#define ANNOTATE_THREAD_NAME(name) /* empty */
#define ANNOTATE_ENABLE_RACE_DETECTION(enable) /* empty */
#endif /* DYNAMIC_ANNOTATIONS_ENABLED */
/* These annotations are also made available to LLVM's Memory Sanitizer */
#if DYNAMIC_ANNOTATIONS_ENABLED == 1 || defined(MEMORY_SANITIZER)
#define ANNOTATE_MEMORY_IS_INITIALIZED(address, size) AnnotateMemoryIsInitialized(__FILE__, __LINE__, address, size)
#define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) AnnotateMemoryIsUninitialized(__FILE__, __LINE__, address, size)
#else
#define ANNOTATE_MEMORY_IS_INITIALIZED(address, size) /* empty */
#define ANNOTATE_MEMORY_IS_UNINITIALIZED(address, size) /* empty */
#endif /* DYNAMIC_ANNOTATIONS_ENABLED || MEMORY_SANITIZER */
/* TODO(delesley) -- Replace __CLANG_SUPPORT_DYN_ANNOTATION__ with the
appropriate feature ID. */
#if defined(__clang__) && (!defined(SWIG)) && defined(__CLANG_SUPPORT_DYN_ANNOTATION__)
#if DYNAMIC_ANNOTATIONS_ENABLED == 0
#define ANNOTALYSIS_ENABLED
#endif
/* When running in opt-mode, GCC will issue a warning, if these attributes are
compiled. Only include them when compiling using Clang. */
#define ATTRIBUTE_IGNORE_READS_BEGIN __attribute((exclusive_lock_function("*")))
#define ATTRIBUTE_IGNORE_READS_END __attribute((unlock_function("*")))
#else
#define ATTRIBUTE_IGNORE_READS_BEGIN /* empty */
#define ATTRIBUTE_IGNORE_READS_END /* empty */
#endif /* defined(__clang__) && ... */
#if (DYNAMIC_ANNOTATIONS_ENABLED != 0) || defined(ANNOTALYSIS_ENABLED)
#define ANNOTATIONS_ENABLED
#endif
#if (DYNAMIC_ANNOTATIONS_ENABLED != 0)
/* Request the analysis tool to ignore all reads in the current thread
until ANNOTATE_IGNORE_READS_END is called.
Useful to ignore intentional racey reads, while still checking
other reads and all writes.
See also ANNOTATE_UNPROTECTED_READ. */
#define ANNOTATE_IGNORE_READS_BEGIN() AnnotateIgnoreReadsBegin(__FILE__, __LINE__)
/* Stop ignoring reads. */
#define ANNOTATE_IGNORE_READS_END() AnnotateIgnoreReadsEnd(__FILE__, __LINE__)
/* Similar to ANNOTATE_IGNORE_READS_BEGIN, but ignore writes instead. */
#define ANNOTATE_IGNORE_WRITES_BEGIN() AnnotateIgnoreWritesBegin(__FILE__, __LINE__)
/* Stop ignoring writes. */
#define ANNOTATE_IGNORE_WRITES_END() AnnotateIgnoreWritesEnd(__FILE__, __LINE__)
/* Clang provides limited support for static thread-safety analysis
through a feature called Annotalysis. We configure macro-definitions
according to whether Annotalysis support is available. */
#elif defined(ANNOTALYSIS_ENABLED)
#define ANNOTATE_IGNORE_READS_BEGIN() StaticAnnotateIgnoreReadsBegin(__FILE__, __LINE__)
#define ANNOTATE_IGNORE_READS_END() StaticAnnotateIgnoreReadsEnd(__FILE__, __LINE__)
#define ANNOTATE_IGNORE_WRITES_BEGIN() StaticAnnotateIgnoreWritesBegin(__FILE__, __LINE__)
#define ANNOTATE_IGNORE_WRITES_END() StaticAnnotateIgnoreWritesEnd(__FILE__, __LINE__)
#else
#define ANNOTATE_IGNORE_READS_BEGIN() /* empty */
#define ANNOTATE_IGNORE_READS_END() /* empty */
#define ANNOTATE_IGNORE_WRITES_BEGIN() /* empty */
#define ANNOTATE_IGNORE_WRITES_END() /* empty */
#endif
/* Implement the ANNOTATE_IGNORE_READS_AND_WRITES_* annotations using the more
primitive annotations defined above. */
#if defined(ANNOTATIONS_ENABLED)
/* Start ignoring all memory accesses (both reads and writes). */
#define ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() \
do { \
ANNOTATE_IGNORE_READS_BEGIN(); \
ANNOTATE_IGNORE_WRITES_BEGIN(); \
} while (0)
/* Stop ignoring both reads and writes. */
#define ANNOTATE_IGNORE_READS_AND_WRITES_END() \
do { \
ANNOTATE_IGNORE_WRITES_END(); \
ANNOTATE_IGNORE_READS_END(); \
} while (0)
#else
#define ANNOTATE_IGNORE_READS_AND_WRITES_BEGIN() /* empty */
#define ANNOTATE_IGNORE_READS_AND_WRITES_END() /* empty */
#endif
/* Use the macros above rather than using these functions directly. */
#include <stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
void AnnotateRWLockCreate(const char* file, int line, const volatile void* lock);
void AnnotateRWLockCreateStatic(const char* file, int line, const volatile void* lock);
void AnnotateRWLockDestroy(const char* file, int line, const volatile void* lock);
void AnnotateRWLockAcquired(const char* file, int line, const volatile void* lock, long is_w); /* NOLINT */
void AnnotateRWLockReleased(const char* file, int line, const volatile void* lock, long is_w); /* NOLINT */
void AnnotateBenignRace(const char* file, int line, const volatile void* address, const char* description);
void AnnotateBenignRaceSized(const char* file,
int line,
const volatile void* address,
size_t size,
const char* description);
void AnnotateThreadName(const char* file, int line, const char* name);
void AnnotateEnableRaceDetection(const char* file, int line, int enable);
void AnnotateMemoryIsInitialized(const char* file, int line, const volatile void* mem, size_t size);
void AnnotateMemoryIsUninitialized(const char* file, int line, const volatile void* mem, size_t size);
/* Annotations expand to these functions, when Dynamic Annotations are enabled.
These functions are either implemented as no-op calls, if no Sanitizer is
attached, or provided with externally-linked implementations by a library
like ThreadSanitizer. */
void AnnotateIgnoreReadsBegin(const char* file, int line) ATTRIBUTE_IGNORE_READS_BEGIN;
void AnnotateIgnoreReadsEnd(const char* file, int line) ATTRIBUTE_IGNORE_READS_END;
void AnnotateIgnoreWritesBegin(const char* file, int line);
void AnnotateIgnoreWritesEnd(const char* file, int line);
#if defined(ANNOTALYSIS_ENABLED)
/* When Annotalysis is enabled without Dynamic Annotations, the use of
static-inline functions allows the annotations to be read at compile-time,
while still letting the compiler elide the functions from the final build.
TODO(delesley) -- The exclusive lock here ignores writes as well, but
allows IGNORE_READS_AND_WRITES to work properly. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
static inline void StaticAnnotateIgnoreReadsBegin(const char* file, int line) ATTRIBUTE_IGNORE_READS_BEGIN {
(void)file;
(void)line;
}
static inline void StaticAnnotateIgnoreReadsEnd(const char* file, int line) ATTRIBUTE_IGNORE_READS_END {
(void)file;
(void)line;
}
static inline void StaticAnnotateIgnoreWritesBegin(const char* file, int line) {
(void)file;
(void)line;
}
static inline void StaticAnnotateIgnoreWritesEnd(const char* file, int line) {
(void)file;
(void)line;
}
#pragma GCC diagnostic pop
#endif
/* Return non-zero value if running under valgrind.
If "valgrind.h" is included into dynamic_annotations.cc,
the regular valgrind mechanism will be used.
See http://valgrind.org/docs/manual/manual-core-adv.html about
RUNNING_ON_VALGRIND and other valgrind "client requests".
The file "valgrind.h" may be obtained by doing
svn co svn://svn.valgrind.org/valgrind/trunk/include
If for some reason you can't use "valgrind.h" or want to fake valgrind,
there are two ways to make this function return non-zero:
- Use environment variable: export RUNNING_ON_VALGRIND=1
- Make your tool intercept the function RunningOnValgrind() and
change its return value.
*/
int RunningOnValgrind(void);
/* ValgrindSlowdown returns:
* 1.0, if (RunningOnValgrind() == 0)
* 50.0, if (RunningOnValgrind() != 0 && getenv("VALGRIND_SLOWDOWN") == NULL)
* atof(getenv("VALGRIND_SLOWDOWN")) otherwise
This function can be used to scale timeout values:
EXAMPLE:
for (;;) {
DoExpensiveBackgroundTask();
SleepForSeconds(5 * ValgrindSlowdown());
}
*/
double ValgrindSlowdown(void);
#ifdef __cplusplus
}
#endif
/* ANNOTATE_UNPROTECTED_READ is the preferred way to annotate racey reads.
Instead of doing
ANNOTATE_IGNORE_READS_BEGIN();
... = x;
ANNOTATE_IGNORE_READS_END();
one can use
... = ANNOTATE_UNPROTECTED_READ(x); */
#if defined(__cplusplus) && defined(ANNOTATIONS_ENABLED)
template <typename T>
inline T ANNOTATE_UNPROTECTED_READ(const volatile T& x) { /* NOLINT */
ANNOTATE_IGNORE_READS_BEGIN();
T res = x;
ANNOTATE_IGNORE_READS_END();
return res;
}
#else
#define ANNOTATE_UNPROTECTED_READ(x) (x)
#endif
#if DYNAMIC_ANNOTATIONS_ENABLED != 0 && defined(__cplusplus)
/* Apply ANNOTATE_BENIGN_RACE_SIZED to a static variable. */
#define ANNOTATE_BENIGN_RACE_STATIC(static_var, description) \
namespace { \
class static_var##_annotator { \
public: \
static_var##_annotator() { \
ANNOTATE_BENIGN_RACE_SIZED(&static_var, sizeof(static_var), #static_var ": " description); \
} \
}; \
static static_var##_annotator the##static_var##_annotator; \
} // namespace
#else /* DYNAMIC_ANNOTATIONS_ENABLED == 0 */
#define ANNOTATE_BENIGN_RACE_STATIC(static_var, description) /* empty */
#endif /* DYNAMIC_ANNOTATIONS_ENABLED */
#ifdef ADDRESS_SANITIZER
/* Describe the current state of a contiguous container such as e.g.
* std::vector or std::string. For more details see
* sanitizer/common_interface_defs.h, which is provided by the compiler. */
#include <sanitizer/common_interface_defs.h>
#define ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid) \
__sanitizer_annotate_contiguous_container(beg, end, old_mid, new_mid)
#define ADDRESS_SANITIZER_REDZONE(name) \
struct { \
char x[8] __attribute__((aligned(8))); \
} name
#else
#define ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid)
#define ADDRESS_SANITIZER_REDZONE(name)
#endif // ADDRESS_SANITIZER
/* Undefine the macros intended only in this file. */
#undef ANNOTALYSIS_ENABLED
#undef ANNOTATIONS_ENABLED
#undef ATTRIBUTE_IGNORE_READS_BEGIN
#undef ATTRIBUTE_IGNORE_READS_END
#endif /* !__native_client__ */
#endif /* ABSL_BASE_DYNAMIC_ANNOTATIONS_H_ */
#define ABSL_RAW_CHECK(cond, msg) assert((cond) && (msg))
#define ABSL_RAW_LOG(sev, ...) \
do { \
} while (0)
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Produce stack trace.
//
// There are three different ways we can try to get the stack trace:
//
// 1) Our hand-coded stack-unwinder. This depends on a certain stack
// layout, which is used by gcc (and those systems using a
// gcc-compatible ABI) on x86 systems, at least since gcc 2.95.
// It uses the frame pointer to do its work.
//
// 2) The libunwind library. This is still in development, and as a
// separate library adds a new dependency, but doesn't need a frame
// pointer. It also doesn't call malloc.
//
// 3) The gdb unwinder -- also the one used by the c++ exception code.
// It's obviously well-tested, but has a fatal flaw: it can call
// malloc() from the unwinder. This is a problem because we're
// trying to use the unwinder to instrument malloc().
//
// Note: if you add a new implementation here, make sure it works
// correctly when absl::GetStackTrace() is called with max_depth == 0.
// Some code may do that.
#include <atomic>
#if defined(ABSL_STACKTRACE_INL_HEADER)
#include ABSL_STACKTRACE_INL_HEADER
#else
#error Cannot calculate stack trace: will need to write for your environment
#include "stacktrace_internal/stacktrace_aarch64-inl.inc"
#include "stacktrace_internal/stacktrace_arm-inl.inc"
#include "stacktrace_internal/stacktrace_generic-inl.inc"
#include "stacktrace_internal/stacktrace_powerpc-inl.inc"
#include "stacktrace_internal/stacktrace_unimplemented-inl.inc"
#include "stacktrace_internal/stacktrace_win32-inl.inc"
#include "stacktrace_internal/stacktrace_x86-inl.inc"
#endif
namespace absl {
namespace {
typedef int (*Unwinder)(void**, int*, int, int, const void*, int*);
std::atomic<Unwinder> custom;
template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT>
ABSL_ATTRIBUTE_ALWAYS_INLINE inline int Unwind(void** result,
int* sizes,
int max_depth,
int skip_count,
const void* uc,
int* min_dropped_frames) {
Unwinder f = &UnwindImpl<IS_STACK_FRAMES, IS_WITH_CONTEXT>;
Unwinder g = custom.load(std::memory_order_acquire);
if (g != nullptr)
f = g;
// Add 1 to skip count for the unwinder function itself
int size = (*f)(result, sizes, max_depth, skip_count + 1, uc, min_dropped_frames);
// To disable tail call to (*f)(...)
ABSL_BLOCK_TAIL_CALL_OPTIMIZATION();
return size;
}
} // anonymous namespace
int GetStackFrames(void** result, int* sizes, int max_depth, int skip_count) {
return Unwind<true, false>(result, sizes, max_depth, skip_count, nullptr, nullptr);
}
int GetStackFramesWithContext(void** result,
int* sizes,
int max_depth,
int skip_count,
const void* uc,
int* min_dropped_frames) {
return Unwind<true, true>(result, sizes, max_depth, skip_count, uc, min_dropped_frames);
}
int GetStackTrace(void** result, int max_depth, int skip_count) {
return Unwind<false, false>(result, nullptr, max_depth, skip_count, nullptr, nullptr);
}
int GetStackTraceWithContext(void** result, int max_depth, int skip_count, const void* uc, int* min_dropped_frames) {
return Unwind<false, true>(result, nullptr, max_depth, skip_count, uc, min_dropped_frames);
}
void SetStackUnwinder(Unwinder w) {
custom.store(w, std::memory_order_release);
}
int DefaultStackUnwinder(void** pcs, int* sizes, int depth, int skip, const void* uc, int* min_dropped_frames) {
skip++; // For this function
Unwinder f = nullptr;
if (sizes == nullptr) {
if (uc == nullptr) {
f = &UnwindImpl<false, false>;
} else {
f = &UnwindImpl<false, true>;
}
} else {
if (uc == nullptr) {
f = &UnwindImpl<true, false>;
} else {
f = &UnwindImpl<true, true>;
}
}
volatile int x = 0;
int n = (*f)(pcs, sizes, depth, skip, uc, min_dropped_frames);
x = 1;
(void)x; // To disable tail call to (*f)(...)
return n;
}
} // namespace absl
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// base::AddressIsReadable() probes an address to see whether it is readable,
// without faulting.
#if !defined(__linux__) || defined(__ANDROID__)
namespace absl {
namespace debug_internal {
// On platforms other than Linux, just return true.
bool AddressIsReadable(const void* /* addr */) {
return true;
}
} // namespace debug_internal
} // namespace absl
#else
#include <fcntl.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <atomic>
#include <cerrno>
#include <cstdint>
namespace absl {
namespace debug_internal {
// Pack a pid and two file descriptors into a 64-bit word,
// using 16, 24, and 24 bits for each respectively.
static uint64_t Pack(uint64_t pid, uint64_t read_fd, uint64_t write_fd) {
ABSL_RAW_CHECK((read_fd >> 24) == 0 && (write_fd >> 24) == 0, "fd out of range");
return (pid << 48) | ((read_fd & 0xffffff) << 24) | (write_fd & 0xffffff);
}
// Unpack x into a pid and two file descriptors, where x was created with
// Pack().
static void Unpack(uint64_t x, int* pid, int* read_fd, int* write_fd) {
*pid = x >> 48;
*read_fd = (x >> 24) & 0xffffff;
*write_fd = x & 0xffffff;
}
// Return whether the byte at *addr is readable, without faulting.
// Save and restores errno. Returns true on systems where
// unimplemented.
// This is a namespace-scoped variable for correct zero-initialization.
static std::atomic<uint64_t> pid_and_fds; // initially 0, an invalid pid.
bool AddressIsReadable(const void* addr) {
int save_errno = errno;
// We test whether a byte is readable by using write(). Normally, this would
// be done via a cached file descriptor to /dev/null, but linux fails to
// check whether the byte is readable when the destination is /dev/null, so
// we use a cached pipe. We store the pid of the process that created the
// pipe to handle the case where a process forks, and the child closes all
// the file descriptors and then calls this routine. This is not perfect:
// the child could use the routine, then close all file descriptors and then
// use this routine again. But the likely use of this routine is when
// crashing, to test the validity of pages when dumping the stack. Beware
// that we may leak file descriptors, but we're unlikely to leak many.
int bytes_written;
int current_pid = getpid() & 0xffff; // we use only the low order 16 bits
do { // until we do not get EBADF trying to use file descriptors
int pid;
int read_fd;
int write_fd;
uint64_t local_pid_and_fds = pid_and_fds.load(std::memory_order_relaxed);
Unpack(local_pid_and_fds, &pid, &read_fd, &write_fd);
while (current_pid != pid) {
int p[2];
// new pipe
if (pipe(p) != 0) {
ABSL_RAW_LOG(FATAL, "Failed to create pipe, errno=%d", errno);
}
fcntl(p[0], F_SETFD, FD_CLOEXEC);
fcntl(p[1], F_SETFD, FD_CLOEXEC);
uint64_t new_pid_and_fds = Pack(current_pid, p[0], p[1]);
if (pid_and_fds.compare_exchange_strong(
local_pid_and_fds, new_pid_and_fds, std::memory_order_relaxed, std::memory_order_relaxed)) {
local_pid_and_fds = new_pid_and_fds; // fds exposed to other threads
} else { // fds not exposed to other threads; we can close them.
close(p[0]);
close(p[1]);
local_pid_and_fds = pid_and_fds.load(std::memory_order_relaxed);
}
Unpack(local_pid_and_fds, &pid, &read_fd, &write_fd);
}
errno = 0;
// Use syscall(SYS_write, ...) instead of write() to prevent ASAN
// and other checkers from complaining about accesses to arbitrary
// memory.
do {
bytes_written = syscall(SYS_write, write_fd, addr, 1);
} while (bytes_written == -1 && errno == EINTR);
if (bytes_written == 1) { // remove the byte from the pipe
char c;
while (read(read_fd, &c, 1) == -1 && errno == EINTR) {
}
}
if (errno == EBADF) { // Descriptors invalid.
// If pid_and_fds contains the problematic file descriptors we just used,
// this call will forget them, and the loop will try again.
pid_and_fds.compare_exchange_strong(
local_pid_and_fds, 0, std::memory_order_relaxed, std::memory_order_relaxed);
}
} while (errno == EBADF);
errno = save_errno;
return bytes_written == 1;
}
} // namespace debug_internal
} // namespace absl
#endif
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Allow dynamic symbol lookup in an in-memory Elf image.
//
#ifdef ABSL_HAVE_ELF_MEM_IMAGE // defined in elf_mem_image.h
#include <string.h>
#include <cassert>
#include <cstddef>
// From binutils/include/elf/common.h (this doesn't appear to be documented
// anywhere else).
//
// /* This flag appears in a Versym structure. It means that the symbol
// is hidden, and is only visible with an explicit version number.
// This is a GNU extension. */
// #define VERSYM_HIDDEN 0x8000
//
// /* This is the mask for the rest of the Versym information. */
// #define VERSYM_VERSION 0x7fff
#define VERSYM_VERSION 0x7fff
namespace absl {
namespace debug_internal {
namespace {
#if __WORDSIZE == 32
const int kElfClass = ELFCLASS32;
int ElfBind(const ElfW(Sym) * symbol) {
return ELF32_ST_BIND(symbol->st_info);
}
int ElfType(const ElfW(Sym) * symbol) {
return ELF32_ST_TYPE(symbol->st_info);
}
#elif __WORDSIZE == 64
const int kElfClass = ELFCLASS64;
int ElfBind(const ElfW(Sym) * symbol) {
return ELF64_ST_BIND(symbol->st_info);
}
int ElfType(const ElfW(Sym) * symbol) {
return ELF64_ST_TYPE(symbol->st_info);
}
#else
const int kElfClass = -1;
int ElfBind(const ElfW(Sym) *) {
ABSL_RAW_LOG(FATAL, "Unexpected word size");
return 0;
}
int ElfType(const ElfW(Sym) *) {
ABSL_RAW_LOG(FATAL, "Unexpected word size");
return 0;
}
#endif
// Extract an element from one of the ELF tables, cast it to desired type.
// This is just a simple arithmetic and a glorified cast.
// Callers are responsible for bounds checking.
template <typename T>
const T* GetTableElement(const ElfW(Ehdr) * ehdr, ElfW(Off) table_offset, ElfW(Word) element_size, size_t index) {
return reinterpret_cast<const T*>(reinterpret_cast<const char*>(ehdr) + table_offset + index * element_size);
}
} // namespace
const void* const ElfMemImage::kInvalidBase = reinterpret_cast<const void*>(~0L);
ElfMemImage::ElfMemImage(const void* base) {
ABSL_RAW_CHECK(base != kInvalidBase, "bad pointer");
Init(base);
}
int ElfMemImage::GetNumSymbols() const {
if (!hash_) {
return 0;
}
// See http://www.caldera.com/developers/gabi/latest/ch5.dynamic.html#hash
return hash_[1];
}
const ElfW(Sym) * ElfMemImage::GetDynsym(int index) const {
ABSL_RAW_CHECK(index < GetNumSymbols(), "index out of range");
return dynsym_ + index;
}
const ElfW(Versym) * ElfMemImage::GetVersym(int index) const {
ABSL_RAW_CHECK(index < GetNumSymbols(), "index out of range");
return versym_ + index;
}
const ElfW(Phdr) * ElfMemImage::GetPhdr(int index) const {
ABSL_RAW_CHECK(index < ehdr_->e_phnum, "index out of range");
return GetTableElement<ElfW(Phdr)>(ehdr_, ehdr_->e_phoff, ehdr_->e_phentsize, index);
}
const char* ElfMemImage::GetDynstr(ElfW(Word) offset) const {
ABSL_RAW_CHECK(offset < strsize_, "offset out of range");
return dynstr_ + offset;
}
const void* ElfMemImage::GetSymAddr(const ElfW(Sym) * sym) const {
if (sym->st_shndx == SHN_UNDEF || sym->st_shndx >= SHN_LORESERVE) {
// Symbol corresponds to "special" (e.g. SHN_ABS) section.
return reinterpret_cast<const void*>(sym->st_value);
}
ABSL_RAW_CHECK(link_base_ < sym->st_value, "symbol out of range");
return GetTableElement<char>(ehdr_, 0, 1, sym->st_value) - link_base_;
}
const ElfW(Verdef) * ElfMemImage::GetVerdef(int index) const {
ABSL_RAW_CHECK(0 <= index && static_cast<size_t>(index) <= verdefnum_, "index out of range");
const ElfW(Verdef)* version_definition = verdef_;
while (version_definition->vd_ndx < index && version_definition->vd_next) {
const char* const version_definition_as_char = reinterpret_cast<const char*>(version_definition);
version_definition =
reinterpret_cast<const ElfW(Verdef)*>(version_definition_as_char + version_definition->vd_next);
}
return version_definition->vd_ndx == index ? version_definition : nullptr;
}
const ElfW(Verdaux) * ElfMemImage::GetVerdefAux(const ElfW(Verdef) * verdef) const {
return reinterpret_cast<const ElfW(Verdaux)*>(verdef + 1);
}
const char* ElfMemImage::GetVerstr(ElfW(Word) offset) const {
ABSL_RAW_CHECK(offset < strsize_, "offset out of range");
return dynstr_ + offset;
}
void ElfMemImage::Init(const void* base) {
ehdr_ = nullptr;
dynsym_ = nullptr;
dynstr_ = nullptr;
versym_ = nullptr;
verdef_ = nullptr;
hash_ = nullptr;
strsize_ = 0;
verdefnum_ = 0;
link_base_ = ~0L; // Sentinel: PT_LOAD .p_vaddr can't possibly be this.
if (!base) {
return;
}
const intptr_t base_as_uintptr_t = reinterpret_cast<uintptr_t>(base);
// Fake VDSO has low bit set.
const bool fake_vdso = ((base_as_uintptr_t & 1) != 0);
base = reinterpret_cast<const void*>(base_as_uintptr_t & ~1);
const char* const base_as_char = reinterpret_cast<const char*>(base);
if (base_as_char[EI_MAG0] != ELFMAG0 || base_as_char[EI_MAG1] != ELFMAG1 || base_as_char[EI_MAG2] != ELFMAG2 ||
base_as_char[EI_MAG3] != ELFMAG3) {
assert(false);
return;
}
int elf_class = base_as_char[EI_CLASS];
if (elf_class != kElfClass) {
assert(false);
return;
}
switch (base_as_char[EI_DATA]) {
case ELFDATA2LSB: {
if (__LITTLE_ENDIAN != __BYTE_ORDER) {
assert(false);
return;
}
break;
}
case ELFDATA2MSB: {
if (__BIG_ENDIAN != __BYTE_ORDER) {
assert(false);
return;
}
break;
}
default: {
assert(false);
return;
}
}
ehdr_ = reinterpret_cast<const ElfW(Ehdr)*>(base);
const ElfW(Phdr)* dynamic_program_header = nullptr;
for (int i = 0; i < ehdr_->e_phnum; ++i) {
const ElfW(Phdr)* const program_header = GetPhdr(i);
switch (program_header->p_type) {
case PT_LOAD:
if (!~link_base_) {
link_base_ = program_header->p_vaddr;
}
break;
case PT_DYNAMIC:
dynamic_program_header = program_header;
break;
}
}
if (!~link_base_ || !dynamic_program_header) {
assert(false);
// Mark this image as not present. Can not recur infinitely.
Init(nullptr);
return;
}
ptrdiff_t relocation = base_as_char - reinterpret_cast<const char*>(link_base_);
ElfW(Dyn)* dynamic_entry = reinterpret_cast<ElfW(Dyn)*>(dynamic_program_header->p_vaddr + relocation);
for (; dynamic_entry->d_tag != DT_NULL; ++dynamic_entry) {
ElfW(Xword) value = dynamic_entry->d_un.d_val;
if (fake_vdso) {
// A complication: in the real VDSO, dynamic entries are not relocated
// (it wasn't loaded by a dynamic loader). But when testing with a
// "fake" dlopen()ed vdso library, the loader relocates some (but
// not all!) of them before we get here.
if (dynamic_entry->d_tag == DT_VERDEF) {
// The only dynamic entry (of the ones we care about) libc-2.3.6
// loader doesn't relocate.
value += relocation;
}
} else {
// Real VDSO. Everything needs to be relocated.
value += relocation;
}
switch (dynamic_entry->d_tag) {
case DT_HASH:
hash_ = reinterpret_cast<ElfW(Word)*>(value);
break;
case DT_SYMTAB:
dynsym_ = reinterpret_cast<ElfW(Sym)*>(value);
break;
case DT_STRTAB:
dynstr_ = reinterpret_cast<const char*>(value);
break;
case DT_VERSYM:
versym_ = reinterpret_cast<ElfW(Versym)*>(value);
break;
case DT_VERDEF:
verdef_ = reinterpret_cast<ElfW(Verdef)*>(value);
break;
case DT_VERDEFNUM:
verdefnum_ = dynamic_entry->d_un.d_val;
break;
case DT_STRSZ:
strsize_ = dynamic_entry->d_un.d_val;
break;
default:
// Unrecognized entries explicitly ignored.
break;
}
}
if (!hash_ || !dynsym_ || !dynstr_ || !versym_ || !verdef_ || !verdefnum_ || !strsize_) {
assert(false); // invalid VDSO
// Mark this image as not present. Can not recur infinitely.
Init(nullptr);
return;
}
}
bool ElfMemImage::LookupSymbol(const char* name, const char* version, int type, SymbolInfo* info_out) const {
for (const SymbolInfo& info : *this) {
if (strcmp(info.name, name) == 0 && strcmp(info.version, version) == 0 && ElfType(info.symbol) == type) {
if (info_out) {
*info_out = info;
}
return true;
}
}
return false;
}
bool ElfMemImage::LookupSymbolByAddress(const void* address, SymbolInfo* info_out) const {
for (const SymbolInfo& info : *this) {
const char* const symbol_start = reinterpret_cast<const char*>(info.address);
const char* const symbol_end = symbol_start + info.symbol->st_size;
if (symbol_start <= address && address < symbol_end) {
if (info_out) {
// Client wants to know details for that symbol (the usual case).
if (ElfBind(info.symbol) == STB_GLOBAL) {
// Strong symbol; just return it.
*info_out = info;
return true;
} else {
// Weak or local. Record it, but keep looking for a strong one.
*info_out = info;
}
} else {
// Client only cares if there is an overlapping symbol.
return true;
}
}
}
return false;
}
ElfMemImage::SymbolIterator::SymbolIterator(const void* const image, int index) : index_(index), image_(image) {}
const ElfMemImage::SymbolInfo* ElfMemImage::SymbolIterator::operator->() const {
return &info_;
}
const ElfMemImage::SymbolInfo& ElfMemImage::SymbolIterator::operator*() const {
return info_;
}
bool ElfMemImage::SymbolIterator::operator==(const SymbolIterator& rhs) const {
return this->image_ == rhs.image_ && this->index_ == rhs.index_;
}
bool ElfMemImage::SymbolIterator::operator!=(const SymbolIterator& rhs) const {
return !(*this == rhs);
}
ElfMemImage::SymbolIterator& ElfMemImage::SymbolIterator::operator++() {
this->Update(1);
return *this;
}
ElfMemImage::SymbolIterator ElfMemImage::begin() const {
SymbolIterator it(this, 0);
it.Update(0);
return it;
}
ElfMemImage::SymbolIterator ElfMemImage::end() const {
return SymbolIterator(this, GetNumSymbols());
}
void ElfMemImage::SymbolIterator::Update(int increment) {
const ElfMemImage* image = reinterpret_cast<const ElfMemImage*>(image_);
ABSL_RAW_CHECK(image->IsPresent() || increment == 0, "");
if (!image->IsPresent()) {
return;
}
index_ += increment;
if (index_ >= image->GetNumSymbols()) {
index_ = image->GetNumSymbols();
return;
}
const ElfW(Sym)* symbol = image->GetDynsym(index_);
const ElfW(Versym)* version_symbol = image->GetVersym(index_);
ABSL_RAW_CHECK(symbol && version_symbol, "");
const char* const symbol_name = image->GetDynstr(symbol->st_name);
const ElfW(Versym) version_index = version_symbol[0] & VERSYM_VERSION;
const ElfW(Verdef)* version_definition = nullptr;
const char* version_name = "";
if (symbol->st_shndx == SHN_UNDEF) {
// Undefined symbols reference DT_VERNEED, not DT_VERDEF, and
// version_index could well be greater than verdefnum_, so calling
// GetVerdef(version_index) may trigger assertion.
} else {
version_definition = image->GetVerdef(version_index);
}
if (version_definition) {
// I am expecting 1 or 2 auxiliary entries: 1 for the version itself,
// optional 2nd if the version has a parent.
ABSL_RAW_CHECK(version_definition->vd_cnt == 1 || version_definition->vd_cnt == 2, "wrong number of entries");
const ElfW(Verdaux)* version_aux = image->GetVerdefAux(version_definition);
version_name = image->GetVerstr(version_aux->vda_name);
}
info_.name = symbol_name;
info_.version = version_name;
info_.address = image->GetSymAddr(symbol);
info_.symbol = symbol;
}
} // namespace debug_internal
} // namespace absl
#endif // ABSL_HAVE_ELF_MEM_IMAGE
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Allow dynamic symbol lookup in the kernel VDSO page.
//
// VDSOSupport -- a class representing kernel VDSO (if present).
#ifdef ABSL_HAVE_VDSO_SUPPORT // defined in vdso_support.h
#include <fcntl.h>
#include <sys/syscall.h>
#include <unistd.h>
#ifndef AT_SYSINFO_EHDR
#define AT_SYSINFO_EHDR 33 // for crosstoolv10
#endif
namespace absl {
namespace debug_internal {
std::atomic<const void*> VDSOSupport::vdso_base_(debug_internal::ElfMemImage::kInvalidBase);
std::atomic<VDSOSupport::GetCpuFn> VDSOSupport::getcpu_fn_(&InitAndGetCPU);
VDSOSupport::VDSOSupport()
// If vdso_base_ is still set to kInvalidBase, we got here
// before VDSOSupport::Init has been called. Call it now.
: image_(vdso_base_.load(std::memory_order_relaxed) == debug_internal::ElfMemImage::kInvalidBase
? Init()
: vdso_base_.load(std::memory_order_relaxed)) {}
// NOTE: we can't use GoogleOnceInit() below, because we can be
// called by tcmalloc, and none of the *once* stuff may be functional yet.
//
// In addition, we hope that the VDSOSupportHelper constructor
// causes this code to run before there are any threads, and before
// InitGoogle() has executed any chroot or setuid calls.
//
// Finally, even if there is a race here, it is harmless, because
// the operation should be idempotent.
const void* VDSOSupport::Init() {
if (vdso_base_.load(std::memory_order_relaxed) == debug_internal::ElfMemImage::kInvalidBase) {
{
// Valgrind zaps AT_SYSINFO_EHDR and friends from the auxv[]
// on stack, and so glibc works as if VDSO was not present.
// But going directly to kernel via /proc/self/auxv below bypasses
// Valgrind zapping. So we check for Valgrind separately.
if (RunningOnValgrind()) {
vdso_base_.store(nullptr, std::memory_order_relaxed);
getcpu_fn_.store(&GetCPUViaSyscall, std::memory_order_relaxed);
return nullptr;
}
int fd = open("/proc/self/auxv", O_RDONLY);
if (fd == -1) {
// Kernel too old to have a VDSO.
vdso_base_.store(nullptr, std::memory_order_relaxed);
getcpu_fn_.store(&GetCPUViaSyscall, std::memory_order_relaxed);
return nullptr;
}
ElfW(auxv_t) aux;
while (read(fd, &aux, sizeof(aux)) == sizeof(aux)) {
if (aux.a_type == AT_SYSINFO_EHDR) {
vdso_base_.store(reinterpret_cast<void*>(aux.a_un.a_val), std::memory_order_relaxed);
break;
}
}
close(fd);
}
if (vdso_base_.load(std::memory_order_relaxed) == debug_internal::ElfMemImage::kInvalidBase) {
// Didn't find AT_SYSINFO_EHDR in auxv[].
vdso_base_.store(nullptr, std::memory_order_relaxed);
}
}
GetCpuFn fn = &GetCPUViaSyscall; // default if VDSO not present.
if (vdso_base_.load(std::memory_order_relaxed)) {
VDSOSupport vdso;
SymbolInfo info;
if (vdso.LookupSymbol("__vdso_getcpu", "LINUX_2.6", STT_FUNC, &info)) {
fn = reinterpret_cast<GetCpuFn>(const_cast<void*>(info.address));
}
}
// Subtle: this code runs outside of any locks; prevent compiler
// from assigning to getcpu_fn_ more than once.
getcpu_fn_.store(fn, std::memory_order_relaxed);
return vdso_base_.load(std::memory_order_relaxed);
}
const void* VDSOSupport::SetBase(const void* base) {
ABSL_RAW_CHECK(base != debug_internal::ElfMemImage::kInvalidBase, "internal error");
const void* old_base = vdso_base_.load(std::memory_order_relaxed);
vdso_base_.store(base, std::memory_order_relaxed);
image_.Init(base);
// Also reset getcpu_fn_, so GetCPU could be tested with simulated VDSO.
getcpu_fn_.store(&InitAndGetCPU, std::memory_order_relaxed);
return old_base;
}
bool VDSOSupport::LookupSymbol(const char* name, const char* version, int type, SymbolInfo* info) const {
return image_.LookupSymbol(name, version, type, info);
}
bool VDSOSupport::LookupSymbolByAddress(const void* address, SymbolInfo* info_out) const {
return image_.LookupSymbolByAddress(address, info_out);
}
// NOLINT on 'long' because this routine mimics kernel api.
long VDSOSupport::GetCPUViaSyscall(unsigned* cpu, // NOLINT(runtime/int)
void*,
void*) {
#ifdef SYS_getcpu
return syscall(SYS_getcpu, cpu, nullptr, nullptr);
#else
// x86_64 never implemented sys_getcpu(), except as a VDSO call.
errno = ENOSYS;
return -1;
#endif
}
// Use fast __vdso_getcpu if available.
long VDSOSupport::InitAndGetCPU(unsigned* cpu, // NOLINT(runtime/int)
void* x,
void* y) {
Init();
GetCpuFn fn = getcpu_fn_.load(std::memory_order_relaxed);
ABSL_RAW_CHECK(fn != &InitAndGetCPU, "Init() did not set getcpu_fn_");
return (*fn)(cpu, x, y);
}
// This function must be very fast, and may be called from very
// low level (e.g. tcmalloc). Hence I avoid things like
// GoogleOnceInit() and ::operator new.
ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY
int GetCPU() {
unsigned cpu;
int ret_code = (*VDSOSupport::getcpu_fn_)(&cpu, nullptr, nullptr);
return ret_code == 0 ? cpu : ret_code;
}
// We need to make sure VDSOSupport::Init() is called before
// InitGoogle() does any setuid or chroot calls. If VDSOSupport
// is used in any global constructor, this will happen, since
// VDSOSupport's constructor calls Init. But if not, we need to
// ensure it here, with a global constructor of our own. This
// is an allowed exception to the normal rule against non-trivial
// global constructors.
static class VDSOInitHelper {
public:
VDSOInitHelper() { VDSOSupport::Init(); }
} vdso_init_helper;
} // namespace debug_internal
} // namespace absl
#endif // ABSL_HAVE_VDSO_SUPPORT
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <stdlib.h>
#include <string.h>
#ifndef __has_feature
#define __has_feature(x) 0
#endif
/* Compiler-based ThreadSanitizer defines
DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL = 1
and provides its own definitions of the functions. */
#ifndef DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL
#define DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL 0
#endif
/* Each function is empty and called (via a macro) only in debug mode.
The arguments are captured by dynamic tools at runtime. */
#if DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL == 0 && !defined(__native_client__)
#if __has_feature(memory_sanitizer)
#include <sanitizer/msan_interface.h>
#endif
#ifdef __cplusplus
extern "C" {
#endif
void AnnotateRWLockCreate(const char*, int, const volatile void*) {}
void AnnotateRWLockDestroy(const char*, int, const volatile void*) {}
void AnnotateRWLockAcquired(const char*, int, const volatile void*, long) {}
void AnnotateRWLockReleased(const char*, int, const volatile void*, long) {}
void AnnotateBenignRace(const char*, int, const volatile void*, const char*) {}
void AnnotateBenignRaceSized(const char*, int, const volatile void*, size_t, const char*) {}
void AnnotateThreadName(const char*, int, const char*) {}
void AnnotateIgnoreReadsBegin(const char*, int) {}
void AnnotateIgnoreReadsEnd(const char*, int) {}
void AnnotateIgnoreWritesBegin(const char*, int) {}
void AnnotateIgnoreWritesEnd(const char*, int) {}
void AnnotateEnableRaceDetection(const char*, int, int) {}
void AnnotateMemoryIsInitialized(const char*, int, const volatile void* mem, size_t size) {
#if __has_feature(memory_sanitizer)
__msan_unpoison(mem, size);
#else
(void)mem;
(void)size;
#endif
}
void AnnotateMemoryIsUninitialized(const char*, int, const volatile void* mem, size_t size) {
#if __has_feature(memory_sanitizer)
__msan_allocated_memory(mem, size);
#else
(void)mem;
(void)size;
#endif
}
static int GetRunningOnValgrind(void) {
#ifdef RUNNING_ON_VALGRIND
if (RUNNING_ON_VALGRIND)
return 1;
#endif
char* running_on_valgrind_str = getenv("RUNNING_ON_VALGRIND");
if (running_on_valgrind_str) {
return strcmp(running_on_valgrind_str, "0") != 0;
}
return 0;
}
/* See the comments in dynamic_annotations.h */
int RunningOnValgrind(void) {
static volatile int running_on_valgrind = -1;
int local_running_on_valgrind = running_on_valgrind;
/* C doesn't have thread-safe initialization of statics, and we
don't want to depend on pthread_once here, so hack it. */
ANNOTATE_BENIGN_RACE(&running_on_valgrind, "safe hack");
if (local_running_on_valgrind == -1)
running_on_valgrind = local_running_on_valgrind = GetRunningOnValgrind();
return local_running_on_valgrind;
}
/* See the comments in dynamic_annotations.h */
double ValgrindSlowdown(void) {
/* Same initialization hack as in RunningOnValgrind(). */
static volatile double slowdown = 0.0;
double local_slowdown = slowdown;
ANNOTATE_BENIGN_RACE(&slowdown, "safe hack");
if (RunningOnValgrind() == 0) {
return 1.0;
}
if (local_slowdown == 0.0) {
char* env = getenv("VALGRIND_SLOWDOWN");
slowdown = local_slowdown = env ? atof(env) : 50.0;
}
return local_slowdown;
}
#ifdef __cplusplus
} // extern "C"
#endif
#endif /* DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL == 0 */