зеркало из https://github.com/mozilla/gecko-dev.git
1064 строки
34 KiB
C++
1064 строки
34 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* API for getting a stack trace of the C/C++ stack on the current thread */
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#include "mozilla/ArrayUtils.h"
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#include "mozilla/Attributes.h"
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#include "mozilla/StackWalk.h"
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#ifdef XP_WIN
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# include "mozilla/StackWalkThread.h"
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# include <io.h>
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#else
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# include <unistd.h>
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#endif
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#include "mozilla/Sprintf.h"
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#include <string.h>
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#if defined(ANDROID) && defined(MOZ_LINKER)
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# include "Linker.h"
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# include <android/log.h>
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#endif
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using namespace mozilla;
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// for _Unwind_Backtrace from libcxxrt or libunwind
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// cxxabi.h from libcxxrt implicitly includes unwind.h first
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#if defined(HAVE__UNWIND_BACKTRACE) && !defined(_GNU_SOURCE)
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# define _GNU_SOURCE
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#endif
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#if defined(HAVE_DLOPEN) || defined(XP_DARWIN)
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# include <dlfcn.h>
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#endif
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#if (defined(XP_DARWIN) && \
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(defined(__i386) || defined(__ppc__) || defined(HAVE__UNWIND_BACKTRACE)))
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# define MOZ_STACKWALK_SUPPORTS_MACOSX 1
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#else
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# define MOZ_STACKWALK_SUPPORTS_MACOSX 0
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#endif
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#if (defined(linux) && \
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((defined(__GNUC__) && (defined(__i386) || defined(PPC))) || \
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defined(HAVE__UNWIND_BACKTRACE)))
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# define MOZ_STACKWALK_SUPPORTS_LINUX 1
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#else
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# define MOZ_STACKWALK_SUPPORTS_LINUX 0
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#endif
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#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1)
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# define HAVE___LIBC_STACK_END 1
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#else
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# define HAVE___LIBC_STACK_END 0
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#endif
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#if HAVE___LIBC_STACK_END
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extern MOZ_EXPORT void* __libc_stack_end; // from ld-linux.so
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#endif
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#ifdef ANDROID
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# include <algorithm>
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# include <unistd.h>
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# include <pthread.h>
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#endif
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class FrameSkipper {
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public:
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constexpr FrameSkipper() : mPc(0) {}
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bool ShouldSkipPC(void* aPC) {
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// Skip frames until we encounter the one we were initialized with,
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// and then never skip again.
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if (mPc != 0) {
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if (mPc != uintptr_t(aPC)) {
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return true;
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}
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mPc = 0;
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}
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return false;
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}
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explicit FrameSkipper(const void* aPc) : mPc(uintptr_t(aPc)) {}
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private:
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uintptr_t mPc;
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};
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#ifdef XP_WIN
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# include <windows.h>
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# include <process.h>
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# include <stdio.h>
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# include <malloc.h>
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# include "mozilla/ArrayUtils.h"
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# include "mozilla/Atomics.h"
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# include "mozilla/StackWalk_windows.h"
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# include "mozilla/WindowsVersion.h"
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# include <imagehlp.h>
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// We need a way to know if we are building for WXP (or later), as if we are, we
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// need to use the newer 64-bit APIs. API_VERSION_NUMBER seems to fit the bill.
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// A value of 9 indicates we want to use the new APIs.
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# if API_VERSION_NUMBER < 9
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# error Too old imagehlp.h
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# endif
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CRITICAL_SECTION gDbgHelpCS;
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# if defined(_M_AMD64) || defined(_M_ARM64)
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// Because various Win64 APIs acquire function-table locks, we need a way of
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// preventing stack walking while those APIs are being called. Otherwise, the
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// stack walker may suspend a thread holding such a lock, and deadlock when the
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// stack unwind code attempts to wait for that lock.
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//
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// We're using an atomic counter rather than a critical section because we
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// don't require mutual exclusion with the stack walker. If the stack walker
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// determines that it's safe to start unwinding the suspended thread (i.e.
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// there are no suppressions when the unwind begins), then it's safe to
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// continue unwinding that thread even if other threads request suppressions
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// in the meantime, because we can't deadlock with those other threads.
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//
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// XXX: This global variable is a larger-than-necessary hammer. A more scoped
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// solution would be to maintain a counter per thread, but then it would be
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// more difficult for WalkStackMain64 to read the suspended thread's counter.
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static Atomic<size_t> sStackWalkSuppressions;
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void SuppressStackWalking() { ++sStackWalkSuppressions; }
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void DesuppressStackWalking() { --sStackWalkSuppressions; }
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MFBT_API
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AutoSuppressStackWalking::AutoSuppressStackWalking() { SuppressStackWalking(); }
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MFBT_API
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AutoSuppressStackWalking::~AutoSuppressStackWalking() {
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DesuppressStackWalking();
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}
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static uint8_t* sJitCodeRegionStart;
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static size_t sJitCodeRegionSize;
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uint8_t* sMsMpegJitCodeRegionStart;
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size_t sMsMpegJitCodeRegionSize;
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MFBT_API void RegisterJitCodeRegion(uint8_t* aStart, size_t aSize) {
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// Currently we can only handle one JIT code region at a time
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MOZ_RELEASE_ASSERT(!sJitCodeRegionStart);
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sJitCodeRegionStart = aStart;
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sJitCodeRegionSize = aSize;
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}
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MFBT_API void UnregisterJitCodeRegion(uint8_t* aStart, size_t aSize) {
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// Currently we can only handle one JIT code region at a time
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MOZ_RELEASE_ASSERT(sJitCodeRegionStart && sJitCodeRegionStart == aStart &&
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sJitCodeRegionSize == aSize);
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sJitCodeRegionStart = nullptr;
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sJitCodeRegionSize = 0;
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}
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# endif // _M_AMD64 || _M_ARM64
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// Routine to print an error message to standard error.
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static void PrintError(const char* aPrefix) {
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LPSTR lpMsgBuf;
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DWORD lastErr = GetLastError();
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FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
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FORMAT_MESSAGE_IGNORE_INSERTS,
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nullptr, lastErr,
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MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
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(LPSTR)&lpMsgBuf, 0, nullptr);
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fprintf(stderr, "### ERROR: %s: %s", aPrefix,
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lpMsgBuf ? lpMsgBuf : "(null)\n");
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fflush(stderr);
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LocalFree(lpMsgBuf);
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}
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static void InitializeDbgHelpCriticalSection() {
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static bool initialized = false;
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if (initialized) {
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return;
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}
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::InitializeCriticalSection(&gDbgHelpCS);
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initialized = true;
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}
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// Wrapper around a reference to a CONTEXT, to simplify access to main
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// platform-specific execution registers.
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// It also avoids using CONTEXT* nullable pointers.
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class CONTEXTGenericAccessors {
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public:
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explicit CONTEXTGenericAccessors(CONTEXT& aCONTEXT) : mCONTEXT(aCONTEXT) {}
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CONTEXT* CONTEXTPtr() { return &mCONTEXT; }
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inline auto& PC() {
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# if defined(_M_AMD64)
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return mCONTEXT.Rip;
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# elif defined(_M_ARM64)
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return mCONTEXT.Pc;
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# elif defined(_M_IX86)
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return mCONTEXT.Eip;
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# else
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# error "unknown platform"
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# endif
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}
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inline auto& SP() {
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# if defined(_M_AMD64)
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return mCONTEXT.Rsp;
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# elif defined(_M_ARM64)
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return mCONTEXT.Sp;
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# elif defined(_M_IX86)
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return mCONTEXT.Esp;
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# else
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# error "unknown platform"
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# endif
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}
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inline auto& BP() {
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# if defined(_M_AMD64)
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return mCONTEXT.Rbp;
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# elif defined(_M_ARM64)
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return mCONTEXT.Fp;
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# elif defined(_M_IX86)
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return mCONTEXT.Ebp;
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# else
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# error "unknown platform"
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# endif
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}
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private:
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CONTEXT& mCONTEXT;
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};
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/**
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* Walk the stack, translating PC's found into strings and recording the
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* chain in aBuffer. For this to work properly, the DLLs must be rebased
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* so that the address in the file agrees with the address in memory.
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* Otherwise StackWalk will return FALSE when it hits a frame in a DLL
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* whose in memory address doesn't match its in-file address.
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*/
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static void DoMozStackWalkThread(MozWalkStackCallback aCallback,
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const void* aFirstFramePC, uint32_t aMaxFrames,
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void* aClosure, HANDLE aThread,
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CONTEXT* aContext) {
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InitializeDbgHelpCriticalSection();
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HANDLE targetThread = aThread;
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bool walkCallingThread;
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if (!targetThread) {
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targetThread = ::GetCurrentThread();
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walkCallingThread = true;
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} else {
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DWORD targetThreadId = ::GetThreadId(targetThread);
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DWORD currentThreadId = ::GetCurrentThreadId();
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walkCallingThread = (targetThreadId == currentThreadId);
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}
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// If not already provided, get a context for the specified thread.
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CONTEXT context_buf;
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if (!aContext) {
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memset(&context_buf, 0, sizeof(CONTEXT));
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context_buf.ContextFlags = CONTEXT_FULL;
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if (walkCallingThread) {
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::RtlCaptureContext(&context_buf);
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} else if (!GetThreadContext(targetThread, &context_buf)) {
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return;
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}
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}
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CONTEXTGenericAccessors context{aContext ? *aContext : context_buf};
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# if defined(_M_IX86)
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// Setup initial stack frame to walk from.
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STACKFRAME64 frame64;
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memset(&frame64, 0, sizeof(frame64));
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frame64.AddrPC.Offset = context.PC();
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frame64.AddrStack.Offset = context.SP();
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frame64.AddrFrame.Offset = context.BP();
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frame64.AddrPC.Mode = AddrModeFlat;
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frame64.AddrStack.Mode = AddrModeFlat;
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frame64.AddrFrame.Mode = AddrModeFlat;
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frame64.AddrReturn.Mode = AddrModeFlat;
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# endif
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# if defined(_M_AMD64) || defined(_M_ARM64)
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// If there are any active suppressions, then at least one thread (we don't
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// know which) is holding a lock that can deadlock RtlVirtualUnwind. Since
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// that thread may be the one that we're trying to unwind, we can't proceed.
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//
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// But if there are no suppressions, then our target thread can't be holding
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// a lock, and it's safe to proceed. By virtue of being suspended, the target
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// thread can't acquire any new locks during the unwind process, so we only
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// need to do this check once. After that, sStackWalkSuppressions can be
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// changed by other threads while we're unwinding, and that's fine because
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// we can't deadlock with those threads.
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if (sStackWalkSuppressions) {
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return;
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}
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# endif
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# if defined(_M_AMD64) || defined(_M_ARM64)
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bool firstFrame = true;
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# endif
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FrameSkipper skipper(aFirstFramePC);
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uint32_t frames = 0;
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// Now walk the stack.
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while (true) {
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DWORD64 addr;
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DWORD64 spaddr;
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# if defined(_M_IX86)
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// 32-bit frame unwinding.
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// Debug routines are not threadsafe, so grab the lock.
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EnterCriticalSection(&gDbgHelpCS);
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BOOL ok = StackWalk64(
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# if defined _M_IX86
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IMAGE_FILE_MACHINE_I386,
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# endif
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::GetCurrentProcess(), targetThread, &frame64, context.CONTEXTPtr(),
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nullptr,
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SymFunctionTableAccess64, // function table access routine
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SymGetModuleBase64, // module base routine
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0);
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LeaveCriticalSection(&gDbgHelpCS);
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if (ok) {
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addr = frame64.AddrPC.Offset;
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spaddr = frame64.AddrStack.Offset;
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} else {
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addr = 0;
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spaddr = 0;
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if (walkCallingThread) {
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PrintError("WalkStack64");
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}
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}
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if (!ok) {
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break;
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}
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# elif defined(_M_AMD64) || defined(_M_ARM64)
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auto currentInstr = context.PC();
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// If we reach a frame in JIT code, we don't have enough information to
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// unwind, so we have to give up.
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if (sJitCodeRegionStart && (uint8_t*)currentInstr >= sJitCodeRegionStart &&
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(uint8_t*)currentInstr < sJitCodeRegionStart + sJitCodeRegionSize) {
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break;
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}
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// We must also avoid msmpeg2vdec.dll's JIT region: they don't generate
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// unwind data, so their JIT unwind callback just throws up its hands and
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// terminates the process.
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if (sMsMpegJitCodeRegionStart &&
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(uint8_t*)currentInstr >= sMsMpegJitCodeRegionStart &&
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(uint8_t*)currentInstr <
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sMsMpegJitCodeRegionStart + sMsMpegJitCodeRegionSize) {
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break;
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}
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// 64-bit frame unwinding.
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// Try to look up unwind metadata for the current function.
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ULONG64 imageBase;
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PRUNTIME_FUNCTION runtimeFunction =
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RtlLookupFunctionEntry(currentInstr, &imageBase, NULL);
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if (runtimeFunction) {
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PVOID dummyHandlerData;
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ULONG64 dummyEstablisherFrame;
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RtlVirtualUnwind(UNW_FLAG_NHANDLER, imageBase, currentInstr,
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runtimeFunction, context.CONTEXTPtr(), &dummyHandlerData,
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&dummyEstablisherFrame, nullptr);
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} else if (firstFrame) {
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// Leaf functions can be unwound by hand.
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context.PC() = *reinterpret_cast<DWORD64*>(context.SP());
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context.SP() += sizeof(void*);
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} else {
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// Something went wrong.
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break;
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}
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addr = context.PC();
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spaddr = context.SP();
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firstFrame = false;
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# else
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# error "unknown platform"
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# endif
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if (addr == 0) {
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break;
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}
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if (skipper.ShouldSkipPC((void*)addr)) {
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continue;
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}
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aCallback(++frames, (void*)addr, (void*)spaddr, aClosure);
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if (aMaxFrames != 0 && frames == aMaxFrames) {
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break;
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}
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# if defined(_M_IX86)
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if (frame64.AddrReturn.Offset == 0) {
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break;
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}
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# endif
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}
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}
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MFBT_API void MozStackWalkThread(MozWalkStackCallback aCallback,
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uint32_t aMaxFrames, void* aClosure,
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HANDLE aThread, CONTEXT* aContext) {
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// We don't pass a aFirstFramePC because we walk the stack for another
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// thread.
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DoMozStackWalkThread(aCallback, nullptr, aMaxFrames, aClosure, aThread,
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aContext);
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}
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MFBT_API void MozStackWalk(MozWalkStackCallback aCallback,
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const void* aFirstFramePC, uint32_t aMaxFrames,
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void* aClosure) {
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DoMozStackWalkThread(aCallback, aFirstFramePC ? aFirstFramePC : CallerPC(),
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aMaxFrames, aClosure, nullptr, nullptr);
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}
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static BOOL CALLBACK callbackEspecial64(PCSTR aModuleName, DWORD64 aModuleBase,
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ULONG aModuleSize, PVOID aUserContext) {
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BOOL retval = TRUE;
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DWORD64 addr = *(DWORD64*)aUserContext;
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/*
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* You'll want to control this if we are running on an
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* architecture where the addresses go the other direction.
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* Not sure this is even a realistic consideration.
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*/
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const BOOL addressIncreases = TRUE;
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/*
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* If it falls in side the known range, load the symbols.
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*/
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if (addressIncreases
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? (addr >= aModuleBase && addr <= (aModuleBase + aModuleSize))
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: (addr <= aModuleBase && addr >= (aModuleBase - aModuleSize))) {
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retval = !!SymLoadModule64(GetCurrentProcess(), nullptr, (PSTR)aModuleName,
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nullptr, aModuleBase, aModuleSize);
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if (!retval) {
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PrintError("SymLoadModule64");
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}
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}
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return retval;
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}
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/*
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* SymGetModuleInfoEspecial
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*
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* Attempt to determine the module information.
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* Bug 112196 says this DLL may not have been loaded at the time
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* SymInitialize was called, and thus the module information
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* and symbol information is not available.
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* This code rectifies that problem.
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*/
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// New members were added to IMAGEHLP_MODULE64 (that show up in the
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// Platform SDK that ships with VC8, but not the Platform SDK that ships
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// with VC7.1, i.e., between DbgHelp 6.0 and 6.1), but we don't need to
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// use them, and it's useful to be able to function correctly with the
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// older library. (Stock Windows XP SP2 seems to ship with dbghelp.dll
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// version 5.1.) Since Platform SDK version need not correspond to
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// compiler version, and the version number in debughlp.h was NOT bumped
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// when these changes were made, ifdef based on a constant that was
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// added between these versions.
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# ifdef SSRVOPT_SETCONTEXT
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# define NS_IMAGEHLP_MODULE64_SIZE \
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(((offsetof(IMAGEHLP_MODULE64, LoadedPdbName) + sizeof(DWORD64) - 1) / \
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sizeof(DWORD64)) * \
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sizeof(DWORD64))
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# else
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# define NS_IMAGEHLP_MODULE64_SIZE sizeof(IMAGEHLP_MODULE64)
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# endif
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BOOL SymGetModuleInfoEspecial64(HANDLE aProcess, DWORD64 aAddr,
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PIMAGEHLP_MODULE64 aModuleInfo,
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PIMAGEHLP_LINE64 aLineInfo) {
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BOOL retval = FALSE;
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/*
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* Init the vars if we have em.
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*/
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aModuleInfo->SizeOfStruct = NS_IMAGEHLP_MODULE64_SIZE;
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if (aLineInfo) {
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aLineInfo->SizeOfStruct = sizeof(IMAGEHLP_LINE64);
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}
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/*
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* Give it a go.
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* It may already be loaded.
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*/
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retval = SymGetModuleInfo64(aProcess, aAddr, aModuleInfo);
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if (retval == FALSE) {
|
|
/*
|
|
* Not loaded, here's the magic.
|
|
* Go through all the modules.
|
|
*/
|
|
// Need to cast to PENUMLOADED_MODULES_CALLBACK64 because the
|
|
// constness of the first parameter of
|
|
// PENUMLOADED_MODULES_CALLBACK64 varies over SDK versions (from
|
|
// non-const to const over time). See bug 391848 and bug
|
|
// 415426.
|
|
BOOL enumRes = EnumerateLoadedModules64(
|
|
aProcess, (PENUMLOADED_MODULES_CALLBACK64)callbackEspecial64,
|
|
(PVOID)&aAddr);
|
|
if (enumRes != FALSE) {
|
|
/*
|
|
* One final go.
|
|
* If it fails, then well, we have other problems.
|
|
*/
|
|
retval = SymGetModuleInfo64(aProcess, aAddr, aModuleInfo);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we got module info, we may attempt line info as well.
|
|
* We will not report failure if this does not work.
|
|
*/
|
|
if (retval != FALSE && aLineInfo) {
|
|
DWORD displacement = 0;
|
|
BOOL lineRes = FALSE;
|
|
lineRes = SymGetLineFromAddr64(aProcess, aAddr, &displacement, aLineInfo);
|
|
if (!lineRes) {
|
|
// Clear out aLineInfo to indicate that it's not valid
|
|
memset(aLineInfo, 0, sizeof(*aLineInfo));
|
|
}
|
|
}
|
|
|
|
return retval;
|
|
}
|
|
|
|
static bool EnsureSymInitialized() {
|
|
static bool gInitialized = false;
|
|
bool retStat;
|
|
|
|
if (gInitialized) {
|
|
return gInitialized;
|
|
}
|
|
|
|
InitializeDbgHelpCriticalSection();
|
|
|
|
SymSetOptions(SYMOPT_LOAD_LINES | SYMOPT_UNDNAME);
|
|
retStat = SymInitialize(GetCurrentProcess(), nullptr, TRUE);
|
|
if (!retStat) {
|
|
PrintError("SymInitialize");
|
|
}
|
|
|
|
gInitialized = retStat;
|
|
/* XXX At some point we need to arrange to call SymCleanup */
|
|
|
|
return retStat;
|
|
}
|
|
|
|
MFBT_API bool MozDescribeCodeAddress(void* aPC,
|
|
MozCodeAddressDetails* aDetails) {
|
|
aDetails->library[0] = '\0';
|
|
aDetails->loffset = 0;
|
|
aDetails->filename[0] = '\0';
|
|
aDetails->lineno = 0;
|
|
aDetails->function[0] = '\0';
|
|
aDetails->foffset = 0;
|
|
|
|
if (!EnsureSymInitialized()) {
|
|
return false;
|
|
}
|
|
|
|
HANDLE myProcess = ::GetCurrentProcess();
|
|
BOOL ok;
|
|
|
|
// debug routines are not threadsafe, so grab the lock.
|
|
EnterCriticalSection(&gDbgHelpCS);
|
|
|
|
//
|
|
// Attempt to load module info before we attempt to resolve the symbol.
|
|
// This just makes sure we get good info if available.
|
|
//
|
|
|
|
DWORD64 addr = (DWORD64)aPC;
|
|
IMAGEHLP_MODULE64 modInfo;
|
|
IMAGEHLP_LINE64 lineInfo;
|
|
BOOL modInfoRes;
|
|
modInfoRes = SymGetModuleInfoEspecial64(myProcess, addr, &modInfo, &lineInfo);
|
|
|
|
if (modInfoRes) {
|
|
strncpy(aDetails->library, modInfo.LoadedImageName,
|
|
sizeof(aDetails->library));
|
|
aDetails->library[mozilla::ArrayLength(aDetails->library) - 1] = '\0';
|
|
aDetails->loffset = (char*)aPC - (char*)modInfo.BaseOfImage;
|
|
|
|
if (lineInfo.FileName) {
|
|
strncpy(aDetails->filename, lineInfo.FileName,
|
|
sizeof(aDetails->filename));
|
|
aDetails->filename[mozilla::ArrayLength(aDetails->filename) - 1] = '\0';
|
|
aDetails->lineno = lineInfo.LineNumber;
|
|
}
|
|
}
|
|
|
|
ULONG64 buffer[(sizeof(SYMBOL_INFO) + MAX_SYM_NAME * sizeof(TCHAR) +
|
|
sizeof(ULONG64) - 1) /
|
|
sizeof(ULONG64)];
|
|
PSYMBOL_INFO pSymbol = (PSYMBOL_INFO)buffer;
|
|
pSymbol->SizeOfStruct = sizeof(SYMBOL_INFO);
|
|
pSymbol->MaxNameLen = MAX_SYM_NAME;
|
|
|
|
DWORD64 displacement;
|
|
ok = SymFromAddr(myProcess, addr, &displacement, pSymbol);
|
|
|
|
if (ok) {
|
|
strncpy(aDetails->function, pSymbol->Name, sizeof(aDetails->function));
|
|
aDetails->function[mozilla::ArrayLength(aDetails->function) - 1] = '\0';
|
|
aDetails->foffset = static_cast<ptrdiff_t>(displacement);
|
|
}
|
|
|
|
LeaveCriticalSection(&gDbgHelpCS); // release our lock
|
|
return true;
|
|
}
|
|
|
|
// i386 or PPC Linux stackwalking code
|
|
#elif HAVE_DLADDR && \
|
|
(HAVE__UNWIND_BACKTRACE || MOZ_STACKWALK_SUPPORTS_LINUX || \
|
|
MOZ_STACKWALK_SUPPORTS_MACOSX)
|
|
|
|
# include <stdlib.h>
|
|
# include <stdio.h>
|
|
|
|
// On glibc 2.1, the Dl_info api defined in <dlfcn.h> is only exposed
|
|
// if __USE_GNU is defined. I suppose its some kind of standards
|
|
// adherence thing.
|
|
//
|
|
# if (__GLIBC_MINOR__ >= 1) && !defined(__USE_GNU)
|
|
# define __USE_GNU
|
|
# endif
|
|
|
|
// This thing is exported by libstdc++
|
|
// Yes, this is a gcc only hack
|
|
# if defined(MOZ_DEMANGLE_SYMBOLS)
|
|
# include <cxxabi.h>
|
|
# endif // MOZ_DEMANGLE_SYMBOLS
|
|
|
|
namespace mozilla {
|
|
|
|
void DemangleSymbol(const char* aSymbol, char* aBuffer, int aBufLen) {
|
|
aBuffer[0] = '\0';
|
|
|
|
# if defined(MOZ_DEMANGLE_SYMBOLS)
|
|
/* See demangle.h in the gcc source for the voodoo */
|
|
char* demangled = abi::__cxa_demangle(aSymbol, 0, 0, 0);
|
|
|
|
if (demangled) {
|
|
strncpy(aBuffer, demangled, aBufLen);
|
|
aBuffer[aBufLen - 1] = '\0';
|
|
free(demangled);
|
|
}
|
|
# endif // MOZ_DEMANGLE_SYMBOLS
|
|
}
|
|
|
|
} // namespace mozilla
|
|
|
|
// {x86, ppc} x {Linux, Mac} stackwalking code.
|
|
# if ((defined(__i386) || defined(PPC) || defined(__ppc__)) && \
|
|
(MOZ_STACKWALK_SUPPORTS_MACOSX || MOZ_STACKWALK_SUPPORTS_LINUX))
|
|
|
|
static void DoFramePointerStackWalk(MozWalkStackCallback aCallback,
|
|
const void* aFirstFramePC,
|
|
uint32_t aMaxFrames, void* aClosure,
|
|
void** aBp, void* aStackEnd);
|
|
|
|
MFBT_API void MozStackWalk(MozWalkStackCallback aCallback,
|
|
const void* aFirstFramePC, uint32_t aMaxFrames,
|
|
void* aClosure) {
|
|
// Get the frame pointer
|
|
void** bp = (void**)__builtin_frame_address(0);
|
|
|
|
void* stackEnd;
|
|
# if HAVE___LIBC_STACK_END
|
|
stackEnd = __libc_stack_end;
|
|
# elif defined(XP_DARWIN)
|
|
stackEnd = pthread_get_stackaddr_np(pthread_self());
|
|
# elif defined(ANDROID)
|
|
pthread_attr_t sattr;
|
|
pthread_attr_init(&sattr);
|
|
pthread_getattr_np(pthread_self(), &sattr);
|
|
void* stackBase = stackEnd = nullptr;
|
|
size_t stackSize = 0;
|
|
if (gettid() != getpid()) {
|
|
// bionic's pthread_attr_getstack doesn't tell the truth for the main
|
|
// thread (see bug 846670). So don't use it for the main thread.
|
|
if (!pthread_attr_getstack(&sattr, &stackBase, &stackSize)) {
|
|
stackEnd = static_cast<char*>(stackBase) + stackSize;
|
|
} else {
|
|
stackEnd = nullptr;
|
|
}
|
|
}
|
|
if (!stackEnd) {
|
|
// So consider the current frame pointer + an arbitrary size of 8MB
|
|
// (modulo overflow ; not really arbitrary as it's the default stack
|
|
// size for the main thread) if pthread_attr_getstack failed for
|
|
// some reason (or was skipped).
|
|
static const uintptr_t kMaxStackSize = 8 * 1024 * 1024;
|
|
uintptr_t maxStackStart = uintptr_t(-1) - kMaxStackSize;
|
|
uintptr_t stackStart = std::max(maxStackStart, uintptr_t(bp));
|
|
stackEnd = reinterpret_cast<void*>(stackStart + kMaxStackSize);
|
|
}
|
|
# else
|
|
# error Unsupported configuration
|
|
# endif
|
|
DoFramePointerStackWalk(aCallback, aFirstFramePC, aMaxFrames, aClosure, bp,
|
|
stackEnd);
|
|
}
|
|
|
|
# elif defined(HAVE__UNWIND_BACKTRACE)
|
|
|
|
// libgcc_s.so symbols _Unwind_Backtrace@@GCC_3.3 and _Unwind_GetIP@@GCC_3.0
|
|
# include <unwind.h>
|
|
|
|
struct unwind_info {
|
|
MozWalkStackCallback callback;
|
|
FrameSkipper skipper;
|
|
int maxFrames;
|
|
int numFrames;
|
|
void* closure;
|
|
};
|
|
|
|
static _Unwind_Reason_Code unwind_callback(struct _Unwind_Context* context,
|
|
void* closure) {
|
|
unwind_info* info = static_cast<unwind_info*>(closure);
|
|
void* pc = reinterpret_cast<void*>(_Unwind_GetIP(context));
|
|
// TODO Use something like '_Unwind_GetGR()' to get the stack pointer.
|
|
if (!info->skipper.ShouldSkipPC(pc)) {
|
|
info->numFrames++;
|
|
(*info->callback)(info->numFrames, pc, nullptr, info->closure);
|
|
if (info->maxFrames != 0 && info->numFrames == info->maxFrames) {
|
|
// Again, any error code that stops the walk will do.
|
|
return _URC_FOREIGN_EXCEPTION_CAUGHT;
|
|
}
|
|
}
|
|
return _URC_NO_REASON;
|
|
}
|
|
|
|
MFBT_API void MozStackWalk(MozWalkStackCallback aCallback,
|
|
const void* aFirstFramePC, uint32_t aMaxFrames,
|
|
void* aClosure) {
|
|
unwind_info info;
|
|
info.callback = aCallback;
|
|
info.skipper = FrameSkipper(aFirstFramePC ? aFirstFramePC : CallerPC());
|
|
info.maxFrames = aMaxFrames;
|
|
info.numFrames = 0;
|
|
info.closure = aClosure;
|
|
|
|
// We ignore the return value from _Unwind_Backtrace. There are three main
|
|
// reasons for this.
|
|
// - On ARM/Android bionic's _Unwind_Backtrace usually (always?) returns
|
|
// _URC_FAILURE. See
|
|
// https://bugzilla.mozilla.org/show_bug.cgi?id=717853#c110.
|
|
// - If aMaxFrames != 0, we want to stop early, and the only way to do that
|
|
// is to make unwind_callback return something other than _URC_NO_REASON,
|
|
// which causes _Unwind_Backtrace to return a non-success code.
|
|
// - MozStackWalk doesn't have a return value anyway.
|
|
(void)_Unwind_Backtrace(unwind_callback, &info);
|
|
}
|
|
|
|
# endif
|
|
|
|
bool MFBT_API MozDescribeCodeAddress(void* aPC,
|
|
MozCodeAddressDetails* aDetails) {
|
|
aDetails->library[0] = '\0';
|
|
aDetails->loffset = 0;
|
|
aDetails->filename[0] = '\0';
|
|
aDetails->lineno = 0;
|
|
aDetails->function[0] = '\0';
|
|
aDetails->foffset = 0;
|
|
|
|
Dl_info info;
|
|
|
|
# if defined(ANDROID) && defined(MOZ_LINKER)
|
|
int ok = __wrap_dladdr(aPC, &info);
|
|
# else
|
|
int ok = dladdr(aPC, &info);
|
|
# endif
|
|
|
|
if (!ok) {
|
|
return true;
|
|
}
|
|
|
|
strncpy(aDetails->library, info.dli_fname, sizeof(aDetails->library));
|
|
aDetails->library[mozilla::ArrayLength(aDetails->library) - 1] = '\0';
|
|
aDetails->loffset = (char*)aPC - (char*)info.dli_fbase;
|
|
|
|
# if !defined(XP_FREEBSD)
|
|
// On FreeBSD, dli_sname is unusably bad, it often returns things like
|
|
// 'gtk_xtbin_new' or 'XRE_GetBootstrap' instead of long C++ symbols. Just let
|
|
// GetFunction do the lookup directly in the ELF image.
|
|
|
|
const char* symbol = info.dli_sname;
|
|
if (!symbol || symbol[0] == '\0') {
|
|
return true;
|
|
}
|
|
|
|
DemangleSymbol(symbol, aDetails->function, sizeof(aDetails->function));
|
|
|
|
if (aDetails->function[0] == '\0') {
|
|
// Just use the mangled symbol if demangling failed.
|
|
strncpy(aDetails->function, symbol, sizeof(aDetails->function));
|
|
aDetails->function[mozilla::ArrayLength(aDetails->function) - 1] = '\0';
|
|
}
|
|
|
|
aDetails->foffset = (char*)aPC - (char*)info.dli_saddr;
|
|
# endif
|
|
|
|
return true;
|
|
}
|
|
|
|
#else // unsupported platform.
|
|
|
|
MFBT_API void MozStackWalk(MozWalkStackCallback aCallback,
|
|
const void* aFirstFramePC, uint32_t aMaxFrames,
|
|
void* aClosure) {}
|
|
|
|
MFBT_API bool MozDescribeCodeAddress(void* aPC,
|
|
MozCodeAddressDetails* aDetails) {
|
|
aDetails->library[0] = '\0';
|
|
aDetails->loffset = 0;
|
|
aDetails->filename[0] = '\0';
|
|
aDetails->lineno = 0;
|
|
aDetails->function[0] = '\0';
|
|
aDetails->foffset = 0;
|
|
return false;
|
|
}
|
|
|
|
#endif
|
|
|
|
#if defined(XP_WIN) || defined(XP_MACOSX) || defined(XP_LINUX)
|
|
|
|
# if defined(XP_MACOSX) && defined(__aarch64__)
|
|
// On macOS arm64, system libraries are arm64e binaries, and arm64e can do
|
|
// pointer authentication: The low bits of the pointer are the actual pointer
|
|
// value, and the high bits are an encrypted hash. During stackwalking, we need
|
|
// to strip off this hash. In theory, ptrauth_strip would be the right function
|
|
// to call for this. However, that function is a no-op unless it's called from
|
|
// code which also builds as arm64e - which we do not. So we cannot use it. So
|
|
// for now, we hardcode a mask that seems to work today: 40 bits for the pointer
|
|
// and 24 bits for the hash seems to do the trick. We can worry about
|
|
// dynamically computing the correct mask if this ever stops working.
|
|
const uintptr_t kPointerMask =
|
|
(uintptr_t(1) << 40) - 1; // 40 bits pointer, 24 bit PAC
|
|
# else
|
|
const uintptr_t kPointerMask = ~uintptr_t(0);
|
|
# endif
|
|
|
|
MOZ_ASAN_IGNORE
|
|
static void DoFramePointerStackWalk(MozWalkStackCallback aCallback,
|
|
const void* aFirstFramePC,
|
|
uint32_t aMaxFrames, void* aClosure,
|
|
void** aBp, void* aStackEnd) {
|
|
// Stack walking code courtesy Kipp's "leaky".
|
|
|
|
FrameSkipper skipper(aFirstFramePC);
|
|
uint32_t numFrames = 0;
|
|
|
|
// Sanitize the given aBp. Assume that something reasonably close to
|
|
// but before the stack end is going be a valid frame pointer. Also
|
|
// check that it is an aligned address. This increases the chances
|
|
// that if the pointer is not valid (which might happen if the caller
|
|
// called __builtin_frame_address(1) and its frame is busted for some
|
|
// reason), we won't read it, leading to a crash. Because the calling
|
|
// code is not using frame pointers when returning, it might actually
|
|
// recover just fine.
|
|
static const uintptr_t kMaxStackSize = 8 * 1024 * 1024;
|
|
if (uintptr_t(aBp) < uintptr_t(aStackEnd) -
|
|
std::min(kMaxStackSize, uintptr_t(aStackEnd)) ||
|
|
aBp >= aStackEnd || (uintptr_t(aBp) & 3)) {
|
|
return;
|
|
}
|
|
|
|
while (aBp) {
|
|
void** next = (void**)*aBp;
|
|
// aBp may not be a frame pointer on i386 if code was compiled with
|
|
// -fomit-frame-pointer, so do some sanity checks.
|
|
// (aBp should be a frame pointer on ppc(64) but checking anyway may help
|
|
// a little if the stack has been corrupted.)
|
|
// We don't need to check against the begining of the stack because
|
|
// we can assume that aBp > sp
|
|
if (next <= aBp || next >= aStackEnd || (uintptr_t(next) & 3)) {
|
|
break;
|
|
}
|
|
# if (defined(__ppc__) && defined(XP_MACOSX)) || defined(__powerpc64__)
|
|
// ppc mac or powerpc64 linux
|
|
void* pc = *(aBp + 2);
|
|
aBp += 3;
|
|
# else // i386 or powerpc32 linux
|
|
void* pc = *(aBp + 1);
|
|
aBp += 2;
|
|
# endif
|
|
|
|
// Strip off pointer authentication hash, if present. For now, it looks
|
|
// like only return addresses require stripping, and stack pointers do
|
|
// not. This might change in the future.
|
|
pc = (void*)((uintptr_t)pc & kPointerMask);
|
|
|
|
if (!skipper.ShouldSkipPC(pc)) {
|
|
// Assume that the SP points to the BP of the function
|
|
// it called. We can't know the exact location of the SP
|
|
// but this should be sufficient for our use the SP
|
|
// to order elements on the stack.
|
|
numFrames++;
|
|
(*aCallback)(numFrames, pc, aBp, aClosure);
|
|
if (aMaxFrames != 0 && numFrames == aMaxFrames) {
|
|
break;
|
|
}
|
|
}
|
|
aBp = next;
|
|
}
|
|
}
|
|
|
|
namespace mozilla {
|
|
|
|
MFBT_API void FramePointerStackWalk(MozWalkStackCallback aCallback,
|
|
uint32_t aMaxFrames, void* aClosure,
|
|
void** aBp, void* aStackEnd) {
|
|
// We don't pass a aFirstFramePC because we start walking the stack from the
|
|
// frame at aBp.
|
|
DoFramePointerStackWalk(aCallback, nullptr, aMaxFrames, aClosure, aBp,
|
|
aStackEnd);
|
|
}
|
|
|
|
} // namespace mozilla
|
|
|
|
#else
|
|
|
|
namespace mozilla {
|
|
MFBT_API void FramePointerStackWalk(MozWalkStackCallback aCallback,
|
|
uint32_t aMaxFrames, void* aClosure,
|
|
void** aBp, void* aStackEnd) {}
|
|
} // namespace mozilla
|
|
|
|
#endif
|
|
|
|
MFBT_API int MozFormatCodeAddressDetails(
|
|
char* aBuffer, uint32_t aBufferSize, uint32_t aFrameNumber, void* aPC,
|
|
const MozCodeAddressDetails* aDetails) {
|
|
return MozFormatCodeAddress(aBuffer, aBufferSize, aFrameNumber, aPC,
|
|
aDetails->function, aDetails->library,
|
|
aDetails->loffset, aDetails->filename,
|
|
aDetails->lineno);
|
|
}
|
|
|
|
MFBT_API int MozFormatCodeAddress(char* aBuffer, uint32_t aBufferSize,
|
|
uint32_t aFrameNumber, const void* aPC,
|
|
const char* aFunction, const char* aLibrary,
|
|
ptrdiff_t aLOffset, const char* aFileName,
|
|
uint32_t aLineNo) {
|
|
const char* function = aFunction && aFunction[0] ? aFunction : "???";
|
|
if (aFileName && aFileName[0]) {
|
|
// We have a filename and (presumably) a line number. Use them.
|
|
return SprintfBuf(aBuffer, aBufferSize, "#%02u: %s (%s:%u)", aFrameNumber,
|
|
function, aFileName, aLineNo);
|
|
} else if (aLibrary && aLibrary[0]) {
|
|
// We have no filename, but we do have a library name. Use it and the
|
|
// library offset, and print them in a way that `fix_stacks.py` can
|
|
// post-process.
|
|
return SprintfBuf(aBuffer, aBufferSize, "#%02u: %s[%s +0x%" PRIxPTR "]",
|
|
aFrameNumber, function, aLibrary,
|
|
static_cast<uintptr_t>(aLOffset));
|
|
} else {
|
|
// We have nothing useful to go on. (The format string is split because
|
|
// '??)' is a trigraph and causes a warning, sigh.)
|
|
return SprintfBuf(aBuffer, aBufferSize,
|
|
"#%02u: ??? (???:???"
|
|
")",
|
|
aFrameNumber);
|
|
}
|
|
}
|
|
|
|
static void EnsureWrite(FILE* aStream, const char* aBuf, size_t aLen) {
|
|
#ifdef XP_WIN
|
|
int fd = _fileno(aStream);
|
|
#else
|
|
int fd = fileno(aStream);
|
|
#endif
|
|
while (aLen > 0) {
|
|
#ifdef XP_WIN
|
|
auto written = _write(fd, aBuf, aLen);
|
|
#else
|
|
auto written = write(fd, aBuf, aLen);
|
|
#endif
|
|
if (written <= 0 || size_t(written) > aLen) {
|
|
break;
|
|
}
|
|
aBuf += written;
|
|
aLen -= written;
|
|
}
|
|
}
|
|
|
|
template <int N>
|
|
static int PrintStackFrameBuf(char (&aBuf)[N], uint32_t aFrameNumber, void* aPC,
|
|
void* aSP) {
|
|
MozCodeAddressDetails details;
|
|
MozDescribeCodeAddress(aPC, &details);
|
|
int len =
|
|
MozFormatCodeAddressDetails(aBuf, N - 1, aFrameNumber, aPC, &details);
|
|
len = std::min(len, N - 2);
|
|
aBuf[len++] = '\n';
|
|
aBuf[len] = '\0';
|
|
return len;
|
|
}
|
|
|
|
static void PrintStackFrame(uint32_t aFrameNumber, void* aPC, void* aSP,
|
|
void* aClosure) {
|
|
FILE* stream = (FILE*)aClosure;
|
|
char buf[1025]; // 1024 + 1 for trailing '\n'
|
|
int len = PrintStackFrameBuf(buf, aFrameNumber, aPC, aSP);
|
|
fflush(stream);
|
|
EnsureWrite(stream, buf, len);
|
|
}
|
|
|
|
static bool WalkTheStackEnabled() {
|
|
static bool result = [] {
|
|
char* value = getenv("MOZ_DISABLE_WALKTHESTACK");
|
|
return !(value && value[0]);
|
|
}();
|
|
return result;
|
|
}
|
|
|
|
MFBT_API void MozWalkTheStack(FILE* aStream, const void* aFirstFramePC,
|
|
uint32_t aMaxFrames) {
|
|
if (WalkTheStackEnabled()) {
|
|
MozStackWalk(PrintStackFrame, aFirstFramePC ? aFirstFramePC : CallerPC(),
|
|
aMaxFrames, aStream);
|
|
}
|
|
}
|
|
|
|
static void WriteStackFrame(uint32_t aFrameNumber, void* aPC, void* aSP,
|
|
void* aClosure) {
|
|
auto writer = (void (*)(const char*))aClosure;
|
|
char buf[1024];
|
|
PrintStackFrameBuf(buf, aFrameNumber, aPC, aSP);
|
|
writer(buf);
|
|
}
|
|
|
|
MFBT_API void MozWalkTheStackWithWriter(void (*aWriter)(const char*),
|
|
const void* aFirstFramePC,
|
|
uint32_t aMaxFrames) {
|
|
if (WalkTheStackEnabled()) {
|
|
MozStackWalk(WriteStackFrame, aFirstFramePC ? aFirstFramePC : CallerPC(),
|
|
aMaxFrames, (void*)aWriter);
|
|
}
|
|
}
|