Squashed 'third_party/gperftools/' content from commit 54505f1
Change-Id: Id02e833828732b0efe7dac722b8485279e67c5fa
git-subtree-dir: third_party/gperftools
git-subtree-split: 54505f1d50c2d1f4676f5e87090b64a117fd980e
diff --git a/src/stacktrace_x86-inl.h b/src/stacktrace_x86-inl.h
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+// -*- 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;
+}