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Diffstat (limited to 'src/third_party/gperftools-2.7/src/stacktrace_x86-inl.h')
| -rw-r--r-- | src/third_party/gperftools-2.7/src/stacktrace_x86-inl.h | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/src/third_party/gperftools-2.7/src/stacktrace_x86-inl.h b/src/third_party/gperftools-2.7/src/stacktrace_x86-inl.h new file mode 100644 index 00000000000..46eb5d82d71 --- /dev/null +++ b/src/third_party/gperftools-2.7/src/stacktrace_x86-inl.h @@ -0,0 +1,354 @@ +// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- +// Copyright (c) 2005, Google Inc. +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +// --- +// Author: Sanjay Ghemawat +// +// Produce stack trace + +#ifndef BASE_STACKTRACE_X86_INL_H_ +#define BASE_STACKTRACE_X86_INL_H_ +// Note: this file is included into stacktrace.cc more than once. +// Anything that should only be defined once should be here: + +#include "config.h" +#include <stdlib.h> // for NULL +#include <assert.h> +#if defined(HAVE_SYS_UCONTEXT_H) +#include <sys/ucontext.h> +#elif defined(HAVE_UCONTEXT_H) +#include <ucontext.h> // for ucontext_t +#elif defined(HAVE_CYGWIN_SIGNAL_H) +// cygwin/signal.h has a buglet where it uses pthread_attr_t without +// #including <pthread.h> itself. So we have to do it. +# ifdef HAVE_PTHREAD +# include <pthread.h> +# endif +#include <cygwin/signal.h> +typedef ucontext ucontext_t; +#endif +#ifdef HAVE_STDINT_H +#include <stdint.h> // for uintptr_t +#endif +#ifdef HAVE_UNISTD_H +#include <unistd.h> +#endif +#ifdef HAVE_MMAP +#include <sys/mman.h> // for msync +#include "base/vdso_support.h" +#endif + +#include "gperftools/stacktrace.h" + +#if defined(__linux__) && defined(__i386__) && defined(__ELF__) && defined(HAVE_MMAP) +// Count "push %reg" instructions in VDSO __kernel_vsyscall(), +// preceding "syscall" or "sysenter". +// If __kernel_vsyscall uses frame pointer, answer 0. +// +// kMaxBytes tells how many instruction bytes of __kernel_vsyscall +// to analyze before giving up. Up to kMaxBytes+1 bytes of +// instructions could be accessed. +// +// Here are known __kernel_vsyscall instruction sequences: +// +// SYSENTER (linux-2.6.26/arch/x86/vdso/vdso32/sysenter.S). +// Used on Intel. +// 0xffffe400 <__kernel_vsyscall+0>: push %ecx +// 0xffffe401 <__kernel_vsyscall+1>: push %edx +// 0xffffe402 <__kernel_vsyscall+2>: push %ebp +// 0xffffe403 <__kernel_vsyscall+3>: mov %esp,%ebp +// 0xffffe405 <__kernel_vsyscall+5>: sysenter +// +// SYSCALL (see linux-2.6.26/arch/x86/vdso/vdso32/syscall.S). +// Used on AMD. +// 0xffffe400 <__kernel_vsyscall+0>: push %ebp +// 0xffffe401 <__kernel_vsyscall+1>: mov %ecx,%ebp +// 0xffffe403 <__kernel_vsyscall+3>: syscall +// +// i386 (see linux-2.6.26/arch/x86/vdso/vdso32/int80.S) +// 0xffffe400 <__kernel_vsyscall+0>: int $0x80 +// 0xffffe401 <__kernel_vsyscall+1>: ret +// +static const int kMaxBytes = 10; + +// We use assert()s instead of DCHECK()s -- this is too low level +// for DCHECK(). + +static int CountPushInstructions(const unsigned char *const addr) { + int result = 0; + for (int i = 0; i < kMaxBytes; ++i) { + if (addr[i] == 0x89) { + // "mov reg,reg" + if (addr[i + 1] == 0xE5) { + // Found "mov %esp,%ebp". + return 0; + } + ++i; // Skip register encoding byte. + } else if (addr[i] == 0x0F && + (addr[i + 1] == 0x34 || addr[i + 1] == 0x05)) { + // Found "sysenter" or "syscall". + return result; + } else if ((addr[i] & 0xF0) == 0x50) { + // Found "push %reg". + ++result; + } else if (addr[i] == 0xCD && addr[i + 1] == 0x80) { + // Found "int $0x80" + assert(result == 0); + return 0; + } else { + // Unexpected instruction. + assert(0 == "unexpected instruction in __kernel_vsyscall"); + return 0; + } + } + // Unexpected: didn't find SYSENTER or SYSCALL in + // [__kernel_vsyscall, __kernel_vsyscall + kMaxBytes) interval. + assert(0 == "did not find SYSENTER or SYSCALL in __kernel_vsyscall"); + return 0; +} +#endif + +// Given a pointer to a stack frame, locate and return the calling +// stackframe, or return NULL if no stackframe can be found. Perform sanity +// checks (the strictness of which is controlled by the boolean parameter +// "STRICT_UNWINDING") to reduce the chance that a bad pointer is returned. +template<bool STRICT_UNWINDING, bool WITH_CONTEXT> +static void **NextStackFrame(void **old_sp, const void *uc) { + void **new_sp = (void **) *old_sp; + +#if defined(__linux__) && defined(__i386__) && defined(HAVE_VDSO_SUPPORT) + if (WITH_CONTEXT && uc != NULL) { + // How many "push %reg" instructions are there at __kernel_vsyscall? + // This is constant for a given kernel and processor, so compute + // it only once. + static int num_push_instructions = -1; // Sentinel: not computed yet. + // Initialize with sentinel value: __kernel_rt_sigreturn can not possibly + // be there. + static const unsigned char *kernel_rt_sigreturn_address = NULL; + static const unsigned char *kernel_vsyscall_address = NULL; + if (num_push_instructions == -1) { + base::VDSOSupport vdso; + if (vdso.IsPresent()) { + base::VDSOSupport::SymbolInfo rt_sigreturn_symbol_info; + base::VDSOSupport::SymbolInfo vsyscall_symbol_info; + if (!vdso.LookupSymbol("__kernel_rt_sigreturn", "LINUX_2.5", + STT_FUNC, &rt_sigreturn_symbol_info) || + !vdso.LookupSymbol("__kernel_vsyscall", "LINUX_2.5", + STT_FUNC, &vsyscall_symbol_info) || + rt_sigreturn_symbol_info.address == NULL || + vsyscall_symbol_info.address == NULL) { + // Unexpected: 32-bit VDSO is present, yet one of the expected + // symbols is missing or NULL. + assert(0 == "VDSO is present, but doesn't have expected symbols"); + num_push_instructions = 0; + } else { + kernel_rt_sigreturn_address = + reinterpret_cast<const unsigned char *>( + rt_sigreturn_symbol_info.address); + kernel_vsyscall_address = + reinterpret_cast<const unsigned char *>( + vsyscall_symbol_info.address); + num_push_instructions = + CountPushInstructions(kernel_vsyscall_address); + } + } else { + num_push_instructions = 0; + } + } + if (num_push_instructions != 0 && kernel_rt_sigreturn_address != NULL && + old_sp[1] == kernel_rt_sigreturn_address) { + const ucontext_t *ucv = static_cast<const ucontext_t *>(uc); + // This kernel does not use frame pointer in its VDSO code, + // and so %ebp is not suitable for unwinding. + void **const reg_ebp = + reinterpret_cast<void **>(ucv->uc_mcontext.gregs[REG_EBP]); + const unsigned char *const reg_eip = + reinterpret_cast<unsigned char *>(ucv->uc_mcontext.gregs[REG_EIP]); + if (new_sp == reg_ebp && + kernel_vsyscall_address <= reg_eip && + reg_eip - kernel_vsyscall_address < kMaxBytes) { + // We "stepped up" to __kernel_vsyscall, but %ebp is not usable. + // Restore from 'ucv' instead. + void **const reg_esp = + reinterpret_cast<void **>(ucv->uc_mcontext.gregs[REG_ESP]); + // Check that alleged %esp is not NULL and is reasonably aligned. + if (reg_esp && + ((uintptr_t)reg_esp & (sizeof(reg_esp) - 1)) == 0) { + // Check that alleged %esp is actually readable. This is to prevent + // "double fault" in case we hit the first fault due to e.g. stack + // corruption. + // + // page_size is linker-initalized to avoid async-unsafe locking + // that GCC would otherwise insert (__cxa_guard_acquire etc). + static int page_size; + if (page_size == 0) { + // First time through. + page_size = getpagesize(); + } + void *const reg_esp_aligned = + reinterpret_cast<void *>( + (uintptr_t)(reg_esp + num_push_instructions - 1) & + ~(page_size - 1)); + if (msync(reg_esp_aligned, page_size, MS_ASYNC) == 0) { + // Alleged %esp is readable, use it for further unwinding. + new_sp = reinterpret_cast<void **>( + reg_esp[num_push_instructions - 1]); + } + } + } + } + } +#endif + + // Check that the transition from frame pointer old_sp to frame + // pointer new_sp isn't clearly bogus + if (STRICT_UNWINDING) { + // With the stack growing downwards, older stack frame must be + // at a greater address that the current one. + if (new_sp <= old_sp) return NULL; + // Assume stack frames larger than 100,000 bytes are bogus. + if ((uintptr_t)new_sp - (uintptr_t)old_sp > 100000) return NULL; + } else { + // In the non-strict mode, allow discontiguous stack frames. + // (alternate-signal-stacks for example). + if (new_sp == old_sp) return NULL; + if (new_sp > old_sp) { + // And allow frames upto about 1MB. + const uintptr_t delta = (uintptr_t)new_sp - (uintptr_t)old_sp; + const uintptr_t acceptable_delta = 1000000; + if (delta > acceptable_delta) { + return NULL; + } + } + } + if ((uintptr_t)new_sp & (sizeof(void *) - 1)) return NULL; +#ifdef __i386__ + // On 64-bit machines, the stack pointer can be very close to + // 0xffffffff, so we explicitly check for a pointer into the + // last two pages in the address space + if ((uintptr_t)new_sp >= 0xffffe000) return NULL; +#endif +#ifdef HAVE_MMAP + if (!STRICT_UNWINDING) { + // Lax sanity checks cause a crash on AMD-based machines with + // VDSO-enabled kernels. + // Make an extra sanity check to insure new_sp is readable. + // Note: NextStackFrame<false>() is only called while the program + // is already on its last leg, so it's ok to be slow here. + static int page_size = getpagesize(); + void *new_sp_aligned = (void *)((uintptr_t)new_sp & ~(page_size - 1)); + if (msync(new_sp_aligned, page_size, MS_ASYNC) == -1) + return NULL; + } +#endif + return new_sp; +} + +#endif // BASE_STACKTRACE_X86_INL_H_ + +// Note: this part of the file is included several times. +// Do not put globals below. + +// The following 4 functions are generated from the code below: +// GetStack{Trace,Frames}() +// GetStack{Trace,Frames}WithContext() +// +// These functions take the following args: +// void** result: the stack-trace, as an array +// int* sizes: the size of each stack frame, as an array +// (GetStackFrames* only) +// int max_depth: the size of the result (and sizes) array(s) +// int skip_count: how many stack pointers to skip before storing in result +// void* ucp: a ucontext_t* (GetStack{Trace,Frames}WithContext only) + +static int GET_STACK_TRACE_OR_FRAMES { + void **sp; +#if (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 2) || __llvm__ + // __builtin_frame_address(0) can return the wrong address on gcc-4.1.0-k8. + // It's always correct on llvm, and the techniques below aren't (in + // particular, llvm-gcc will make a copy of pcs, so it's not in sp[2]), + // so we also prefer __builtin_frame_address when running under llvm. + sp = reinterpret_cast<void**>(__builtin_frame_address(0)); +#elif defined(__i386__) + // Stack frame format: + // sp[0] pointer to previous frame + // sp[1] caller address + // sp[2] first argument + // ... + // NOTE: This will break under llvm, since result is a copy and not in sp[2] + sp = (void **)&result - 2; +#elif defined(__x86_64__) + unsigned long rbp; + // Move the value of the register %rbp into the local variable rbp. + // We need 'volatile' to prevent this instruction from getting moved + // around during optimization to before function prologue is done. + // An alternative way to achieve this + // would be (before this __asm__ instruction) to call Noop() defined as + // static void Noop() __attribute__ ((noinline)); // prevent inlining + // static void Noop() { asm(""); } // prevent optimizing-away + __asm__ volatile ("mov %%rbp, %0" : "=r" (rbp)); + // Arguments are passed in registers on x86-64, so we can't just + // offset from &result + sp = (void **) rbp; +#else +# error Using stacktrace_x86-inl.h on a non x86 architecture! +#endif + + skip_count++; // skip parent's frame due to indirection in stacktrace.cc + + int n = 0; + while (sp && n < max_depth) { + if (*(sp+1) == reinterpret_cast<void *>(0)) { + // In 64-bit code, we often see a frame that + // points to itself and has a return address of 0. + break; + } +#if !IS_WITH_CONTEXT + const void *const ucp = NULL; +#endif + void **next_sp = NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(sp, ucp); + if (skip_count > 0) { + skip_count--; + } else { + result[n] = *(sp+1); +#if IS_STACK_FRAMES + if (next_sp > sp) { + sizes[n] = (uintptr_t)next_sp - (uintptr_t)sp; + } else { + // A frame-size of 0 is used to indicate unknown frame size. + sizes[n] = 0; + } +#endif + n++; + } + sp = next_sp; + } + return n; +} |