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gecko-dev/mozglue/misc/StackWalk.cpp

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* API for getting a stack trace of the C/C++ stack on the current thread */
#include "mozilla/ArrayUtils.h"
#include "mozilla/Assertions.h"
#include "mozilla/IntegerPrintfMacros.h"
#include "mozilla/StackWalk.h"
#include <string.h>
#if defined(_MSC_VER) && _MSC_VER < 1900
#define snprintf _snprintf
#endif
using namespace mozilla;
// The presence of this address is the stack must stop the stack walk. If
// there is no such address, the structure will be {nullptr, true}.
struct CriticalAddress
{
void* mAddr;
bool mInit;
};
static CriticalAddress gCriticalAddress;
// for _Unwind_Backtrace from libcxxrt or libunwind
// cxxabi.h from libcxxrt implicitly includes unwind.h first
#if defined(HAVE__UNWIND_BACKTRACE) && !defined(_GNU_SOURCE)
#define _GNU_SOURCE
#endif
#if defined(HAVE_DLOPEN) || defined(XP_DARWIN)
#include <dlfcn.h>
#endif
#define MOZ_STACKWALK_SUPPORTS_MACOSX \
(defined(XP_DARWIN) && \
(defined(__i386) || defined(__ppc__) || defined(HAVE__UNWIND_BACKTRACE)))
#define MOZ_STACKWALK_SUPPORTS_LINUX \
(defined(linux) && \
((defined(__GNUC__) && (defined(__i386) || defined(PPC))) || \
defined(HAVE__UNWIND_BACKTRACE)))
#if MOZ_STACKWALK_SUPPORTS_MACOSX
#include <pthread.h>
#include <sys/errno.h>
#ifdef MOZ_WIDGET_COCOA
#include <CoreServices/CoreServices.h>
#endif
#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1)
#define HAVE___LIBC_STACK_END 1
#else
#define HAVE___LIBC_STACK_END 0
#endif
#if HAVE___LIBC_STACK_END
extern MOZ_EXPORT void* __libc_stack_end; // from ld-linux.so
#endif
typedef void
malloc_logger_t(uint32_t aType,
uintptr_t aArg1, uintptr_t aArg2, uintptr_t aArg3,
uintptr_t aResult, uint32_t aNumHotFramesToSkip);
extern malloc_logger_t* malloc_logger;
static void
stack_callback(uint32_t aFrameNumber, void* aPc, void* aSp, void* aClosure)
{
const char* name = static_cast<char*>(aClosure);
Dl_info info;
// On Leopard dladdr returns the wrong value for "new_sem_from_pool". The
// stack shows up as having two pthread_cond_wait$UNIX2003 frames. The
// correct one is the first that we find on our way up, so the
// following check for gCriticalAddress.mAddr is critical.
if (gCriticalAddress.mAddr || dladdr(aPc, &info) == 0 ||
!info.dli_sname || strcmp(info.dli_sname, name) != 0) {
return;
}
gCriticalAddress.mAddr = aPc;
}
#if defined(MOZ_WIDGET_COCOA) && defined(DEBUG)
#define MAC_OS_X_VERSION_10_7_HEX 0x00001070
static int32_t OSXVersion()
{
static int32_t gOSXVersion = 0x0;
if (gOSXVersion == 0x0) {
OSErr err = ::Gestalt(gestaltSystemVersion, (SInt32*)&gOSXVersion);
MOZ_ASSERT(err == noErr);
}
return gOSXVersion;
}
static bool OnLionOrLater()
{
return (OSXVersion() >= MAC_OS_X_VERSION_10_7_HEX);
}
#endif
static void
my_malloc_logger(uint32_t aType,
uintptr_t aArg1, uintptr_t aArg2, uintptr_t aArg3,
uintptr_t aResult, uint32_t aNumHotFramesToSkip)
{
static bool once = false;
if (once) {
return;
}
once = true;
// On Leopard dladdr returns the wrong value for "new_sem_from_pool". The
// stack shows up as having two pthread_cond_wait$UNIX2003 frames.
const char* name = "new_sem_from_pool";
MozStackWalk(stack_callback, /* skipFrames */ 0, /* maxFrames */ 0,
const_cast<char*>(name), 0, nullptr);
}
// This is called from NS_LogInit() and from the stack walking functions, but
// only the first call has any effect. We need to call this function from both
// places because it must run before any mutexes are created, and also before
// any objects whose refcounts we're logging are created. Running this
// function during NS_LogInit() ensures that we meet the first criterion, and
// running this function during the stack walking functions ensures we meet the
// second criterion.
MFBT_API void
StackWalkInitCriticalAddress()
{
if (gCriticalAddress.mInit) {
return;
}
gCriticalAddress.mInit = true;
// We must not do work when 'new_sem_from_pool' calls realloc, since
// it holds a non-reentrant spin-lock and we will quickly deadlock.
// new_sem_from_pool is not directly accessible using dlsym, so
// we force a situation where new_sem_from_pool is on the stack and
// use dladdr to check the addresses.
// malloc_logger can be set by external tools like 'Instruments' or 'leaks'
malloc_logger_t* old_malloc_logger = malloc_logger;
malloc_logger = my_malloc_logger;
pthread_cond_t cond;
int r = pthread_cond_init(&cond, 0);
MOZ_ASSERT(r == 0);
pthread_mutex_t mutex;
r = pthread_mutex_init(&mutex, 0);
MOZ_ASSERT(r == 0);
r = pthread_mutex_lock(&mutex);
MOZ_ASSERT(r == 0);
struct timespec abstime = { 0, 1 };
r = pthread_cond_timedwait_relative_np(&cond, &mutex, &abstime);
// restore the previous malloc logger
malloc_logger = old_malloc_logger;
// On Lion, malloc is no longer called from pthread_cond_*wait*. This prevents
// us from finding the address, but that is fine, since with no call to malloc
// there is no critical address.
#ifdef MOZ_WIDGET_COCOA
MOZ_ASSERT(OnLionOrLater() || gCriticalAddress.mAddr != nullptr);
#endif
MOZ_ASSERT(r == ETIMEDOUT);
r = pthread_mutex_unlock(&mutex);
MOZ_ASSERT(r == 0);
r = pthread_mutex_destroy(&mutex);
MOZ_ASSERT(r == 0);
r = pthread_cond_destroy(&cond);
MOZ_ASSERT(r == 0);
}
static bool
IsCriticalAddress(void* aPC)
{
return gCriticalAddress.mAddr == aPC;
}
#else
static bool
IsCriticalAddress(void* aPC)
{
return false;
}
// We still initialize gCriticalAddress.mInit so that this code behaves
// the same on all platforms. Otherwise a failure to init would be visible
// only on OS X.
MFBT_API void
StackWalkInitCriticalAddress()
{
gCriticalAddress.mInit = true;
}
#endif
#if defined(_WIN32) && (defined(_M_IX86) || defined(_M_AMD64) || defined(_M_IA64)) // WIN32 x86 stack walking code
#include <windows.h>
#include <process.h>
#include <stdio.h>
#include <malloc.h>
#include "mozilla/ArrayUtils.h"
#include <imagehlp.h>
// We need a way to know if we are building for WXP (or later), as if we are, we
// need to use the newer 64-bit APIs. API_VERSION_NUMBER seems to fit the bill.
// A value of 9 indicates we want to use the new APIs.
#if API_VERSION_NUMBER < 9
#error Too old imagehlp.h
#endif
struct WalkStackData
{
// Are we walking the stack of the calling thread? Note that we need to avoid
// calling fprintf and friends if this is false, in order to avoid deadlocks.
bool walkCallingThread;
uint32_t skipFrames;
HANDLE thread;
HANDLE process;
HANDLE eventStart;
HANDLE eventEnd;
void** pcs;
uint32_t pc_size;
uint32_t pc_count;
uint32_t pc_max;
void** sps;
uint32_t sp_size;
uint32_t sp_count;
void* platformData;
};
DWORD gStackWalkThread;
CRITICAL_SECTION gDbgHelpCS;
// Routine to print an error message to standard error.
static void
PrintError(const char* aPrefix)
{
LPVOID lpMsgBuf;
DWORD lastErr = GetLastError();
FormatMessageA(
FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
nullptr,
lastErr,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
(LPSTR)&lpMsgBuf,
0,
nullptr
);
fprintf(stderr, "### ERROR: %s: %s",
aPrefix, lpMsgBuf ? lpMsgBuf : "(null)\n");
fflush(stderr);
LocalFree(lpMsgBuf);
}
static unsigned int WINAPI WalkStackThread(void* aData);
static bool
EnsureWalkThreadReady()
{
static bool walkThreadReady = false;
static HANDLE stackWalkThread = nullptr;
static HANDLE readyEvent = nullptr;
if (walkThreadReady) {
return walkThreadReady;
}
if (!stackWalkThread) {
readyEvent = ::CreateEvent(nullptr, FALSE /* auto-reset*/,
FALSE /* initially non-signaled */,
nullptr);
if (!readyEvent) {
PrintError("CreateEvent");
return false;
}
unsigned int threadID;
stackWalkThread = (HANDLE)_beginthreadex(nullptr, 0, WalkStackThread,
(void*)readyEvent, 0, &threadID);
if (!stackWalkThread) {
PrintError("CreateThread");
::CloseHandle(readyEvent);
readyEvent = nullptr;
return false;
}
gStackWalkThread = threadID;
::CloseHandle(stackWalkThread);
}
MOZ_ASSERT((stackWalkThread && readyEvent) ||
(!stackWalkThread && !readyEvent));
// The thread was created. Try to wait an arbitrary amount of time (1 second
// should be enough) for its event loop to start before posting events to it.
DWORD waitRet = ::WaitForSingleObject(readyEvent, 1000);
if (waitRet == WAIT_TIMEOUT) {
// We get a timeout if we're called during static initialization because
// the thread will only start executing after we return so it couldn't
// have signalled the event. If that is the case, give up for now and
// try again next time we're called.
return false;
}
::CloseHandle(readyEvent);
stackWalkThread = nullptr;
readyEvent = nullptr;
::InitializeCriticalSection(&gDbgHelpCS);
return walkThreadReady = true;
}
static void
WalkStackMain64(struct WalkStackData* aData)
{
// Get a context for the specified thread.
CONTEXT context;
if (!aData->platformData) {
memset(&context, 0, sizeof(CONTEXT));
context.ContextFlags = CONTEXT_FULL;
if (!GetThreadContext(aData->thread, &context)) {
if (aData->walkCallingThread) {
PrintError("GetThreadContext");
}
return;
}
} else {
context = *static_cast<CONTEXT*>(aData->platformData);
}
#if defined(_M_IX86) || defined(_M_IA64)
// Setup initial stack frame to walk from.
STACKFRAME64 frame64;
memset(&frame64, 0, sizeof(frame64));
#ifdef _M_IX86
frame64.AddrPC.Offset = context.Eip;
frame64.AddrStack.Offset = context.Esp;
frame64.AddrFrame.Offset = context.Ebp;
#elif defined _M_IA64
frame64.AddrPC.Offset = context.StIIP;
frame64.AddrStack.Offset = context.SP;
frame64.AddrFrame.Offset = context.RsBSP;
#endif
frame64.AddrPC.Mode = AddrModeFlat;
frame64.AddrStack.Mode = AddrModeFlat;
frame64.AddrFrame.Mode = AddrModeFlat;
frame64.AddrReturn.Mode = AddrModeFlat;
#endif
// Skip our own stack walking frames.
int skip = (aData->walkCallingThread ? 3 : 0) + aData->skipFrames;
// Now walk the stack.
while (true) {
DWORD64 addr;
DWORD64 spaddr;
#if defined(_M_IX86) || defined(_M_IA64)
// 32-bit frame unwinding.
// Debug routines are not threadsafe, so grab the lock.
EnterCriticalSection(&gDbgHelpCS);
BOOL ok = StackWalk64(
#if defined _M_IA64
IMAGE_FILE_MACHINE_IA64,
#elif defined _M_IX86
IMAGE_FILE_MACHINE_I386,
#endif
aData->process,
aData->thread,
&frame64,
&context,
nullptr,
SymFunctionTableAccess64, // function table access routine
SymGetModuleBase64, // module base routine
0
);
LeaveCriticalSection(&gDbgHelpCS);
if (ok) {
addr = frame64.AddrPC.Offset;
spaddr = frame64.AddrStack.Offset;
} else {
addr = 0;
spaddr = 0;
if (aData->walkCallingThread) {
PrintError("WalkStack64");
}
}
if (!ok) {
break;
}
#elif defined(_M_AMD64)
// 64-bit frame unwinding.
// Try to look up unwind metadata for the current function.
ULONG64 imageBase;
PRUNTIME_FUNCTION runtimeFunction =
RtlLookupFunctionEntry(context.Rip, &imageBase, NULL);
if (!runtimeFunction) {
// Alas, this is probably a JIT frame, for which we don't generate unwind
// info and so we have to give up.
break;
}
PVOID dummyHandlerData;
ULONG64 dummyEstablisherFrame;
RtlVirtualUnwind(UNW_FLAG_NHANDLER,
imageBase,
context.Rip,
runtimeFunction,
&context,
&dummyHandlerData,
&dummyEstablisherFrame,
nullptr);
addr = context.Rip;
spaddr = context.Rsp;
#else
#error "unknown platform"
#endif
if (addr == 0) {
break;
}
if (skip-- > 0) {
continue;
}
if (aData->pc_count < aData->pc_size) {
aData->pcs[aData->pc_count] = (void*)addr;
}
++aData->pc_count;
if (aData->sp_count < aData->sp_size) {
aData->sps[aData->sp_count] = (void*)spaddr;
}
++aData->sp_count;
if (aData->pc_max != 0 && aData->pc_count == aData->pc_max) {
break;
}
#if defined(_M_IX86) || defined(_M_IA64)
if (frame64.AddrReturn.Offset == 0) {
break;
}
#endif
}
}
static unsigned int WINAPI
WalkStackThread(void* aData)
{
BOOL msgRet;
MSG msg;
// Call PeekMessage to force creation of a message queue so that
// other threads can safely post events to us.
::PeekMessage(&msg, nullptr, WM_USER, WM_USER, PM_NOREMOVE);
// and tell the thread that created us that we're ready.
HANDLE readyEvent = (HANDLE)aData;
::SetEvent(readyEvent);
while ((msgRet = ::GetMessage(&msg, (HWND)-1, 0, 0)) != 0) {
if (msgRet == -1) {
PrintError("GetMessage");
} else {
DWORD ret;
struct WalkStackData* data = (WalkStackData*)msg.lParam;
if (!data) {
continue;
}
// Don't suspend the calling thread until it's waiting for
// us; otherwise the number of frames on the stack could vary.
ret = ::WaitForSingleObject(data->eventStart, INFINITE);
if (ret != WAIT_OBJECT_0) {
PrintError("WaitForSingleObject");
}
// Suspend the calling thread, dump his stack, and then resume him.
// He's currently waiting for us to finish so now should be a good time.
ret = ::SuspendThread(data->thread);
if (ret == -1) {
PrintError("ThreadSuspend");
} else {
WalkStackMain64(data);
ret = ::ResumeThread(data->thread);
if (ret == -1) {
PrintError("ThreadResume");
}
}
::SetEvent(data->eventEnd);
}
}
return 0;
}
/**
* Walk the stack, translating PC's found into strings and recording the
* chain in aBuffer. For this to work properly, the DLLs must be rebased
* so that the address in the file agrees with the address in memory.
* Otherwise StackWalk will return FALSE when it hits a frame in a DLL
* whose in memory address doesn't match its in-file address.
*/
MFBT_API bool
MozStackWalk(MozWalkStackCallback aCallback, uint32_t aSkipFrames,
uint32_t aMaxFrames, void* aClosure, uintptr_t aThread,
void* aPlatformData)
{
StackWalkInitCriticalAddress();
static HANDLE myProcess = nullptr;
HANDLE myThread;
DWORD walkerReturn;
struct WalkStackData data;
if (!EnsureWalkThreadReady()) {
return false;
}
HANDLE currentThread = ::GetCurrentThread();
HANDLE targetThread =
aThread ? reinterpret_cast<HANDLE>(aThread) : currentThread;
data.walkCallingThread = (targetThread == currentThread);
// Have to duplicate handle to get a real handle.
if (!myProcess) {
if (!::DuplicateHandle(::GetCurrentProcess(),
::GetCurrentProcess(),
::GetCurrentProcess(),
&myProcess,
PROCESS_ALL_ACCESS, FALSE, 0)) {
if (data.walkCallingThread) {
PrintError("DuplicateHandle (process)");
}
return false;
}
}
if (!::DuplicateHandle(::GetCurrentProcess(),
targetThread,
::GetCurrentProcess(),
&myThread,
THREAD_ALL_ACCESS, FALSE, 0)) {
if (data.walkCallingThread) {
PrintError("DuplicateHandle (thread)");
}
return false;
}
data.skipFrames = aSkipFrames;
data.thread = myThread;
data.process = myProcess;
void* local_pcs[1024];
data.pcs = local_pcs;
data.pc_count = 0;
data.pc_size = ArrayLength(local_pcs);
data.pc_max = aMaxFrames;
void* local_sps[1024];
data.sps = local_sps;
data.sp_count = 0;
data.sp_size = ArrayLength(local_sps);
data.platformData = aPlatformData;
if (aThread) {
// If we're walking the stack of another thread, we don't need to
// use a separate walker thread.
WalkStackMain64(&data);
if (data.pc_count > data.pc_size) {
data.pcs = (void**)_alloca(data.pc_count * sizeof(void*));
data.pc_size = data.pc_count;
data.pc_count = 0;
data.sps = (void**)_alloca(data.sp_count * sizeof(void*));
data.sp_size = data.sp_count;
data.sp_count = 0;
WalkStackMain64(&data);
}
} else {
data.eventStart = ::CreateEvent(nullptr, FALSE /* auto-reset*/,
FALSE /* initially non-signaled */, nullptr);
data.eventEnd = ::CreateEvent(nullptr, FALSE /* auto-reset*/,
FALSE /* initially non-signaled */, nullptr);
::PostThreadMessage(gStackWalkThread, WM_USER, 0, (LPARAM)&data);
walkerReturn = ::SignalObjectAndWait(data.eventStart,
data.eventEnd, INFINITE, FALSE);
if (walkerReturn != WAIT_OBJECT_0 && data.walkCallingThread) {
PrintError("SignalObjectAndWait (1)");
}
if (data.pc_count > data.pc_size) {
data.pcs = (void**)_alloca(data.pc_count * sizeof(void*));
data.pc_size = data.pc_count;
data.pc_count = 0;
data.sps = (void**)_alloca(data.sp_count * sizeof(void*));
data.sp_size = data.sp_count;
data.sp_count = 0;
::PostThreadMessage(gStackWalkThread, WM_USER, 0, (LPARAM)&data);
walkerReturn = ::SignalObjectAndWait(data.eventStart,
data.eventEnd, INFINITE, FALSE);
if (walkerReturn != WAIT_OBJECT_0 && data.walkCallingThread) {
PrintError("SignalObjectAndWait (2)");
}
}
::CloseHandle(data.eventStart);
::CloseHandle(data.eventEnd);
}
::CloseHandle(myThread);
for (uint32_t i = 0; i < data.pc_count; ++i) {
(*aCallback)(i + 1, data.pcs[i], data.sps[i], aClosure);
}
return data.pc_count != 0;
}
static BOOL CALLBACK
callbackEspecial64(
PCSTR aModuleName,
DWORD64 aModuleBase,
ULONG aModuleSize,
PVOID aUserContext)
{
BOOL retval = TRUE;
DWORD64 addr = *(DWORD64*)aUserContext;
/*
* You'll want to control this if we are running on an
* architecture where the addresses go the other direction.
* Not sure this is even a realistic consideration.
*/
const BOOL addressIncreases = TRUE;
/*
* If it falls in side the known range, load the symbols.
*/
if (addressIncreases
? (addr >= aModuleBase && addr <= (aModuleBase + aModuleSize))
: (addr <= aModuleBase && addr >= (aModuleBase - aModuleSize))
) {
retval = !!SymLoadModule64(GetCurrentProcess(), nullptr,
(PSTR)aModuleName, nullptr,
aModuleBase, aModuleSize);
if (!retval) {
PrintError("SymLoadModule64");
}
}
return retval;
}
/*
* SymGetModuleInfoEspecial
*
* Attempt to determine the module information.
* Bug 112196 says this DLL may not have been loaded at the time
* SymInitialize was called, and thus the module information
* and symbol information is not available.
* This code rectifies that problem.
*/
// New members were added to IMAGEHLP_MODULE64 (that show up in the
// Platform SDK that ships with VC8, but not the Platform SDK that ships
// with VC7.1, i.e., between DbgHelp 6.0 and 6.1), but we don't need to
// use them, and it's useful to be able to function correctly with the
// older library. (Stock Windows XP SP2 seems to ship with dbghelp.dll
// version 5.1.) Since Platform SDK version need not correspond to
// compiler version, and the version number in debughlp.h was NOT bumped
// when these changes were made, ifdef based on a constant that was
// added between these versions.
#ifdef SSRVOPT_SETCONTEXT
#define NS_IMAGEHLP_MODULE64_SIZE (((offsetof(IMAGEHLP_MODULE64, LoadedPdbName) + sizeof(DWORD64) - 1) / sizeof(DWORD64)) * sizeof(DWORD64))
#else
#define NS_IMAGEHLP_MODULE64_SIZE sizeof(IMAGEHLP_MODULE64)
#endif
BOOL SymGetModuleInfoEspecial64(HANDLE aProcess, DWORD64 aAddr,
PIMAGEHLP_MODULE64 aModuleInfo,
PIMAGEHLP_LINE64 aLineInfo)
{
BOOL retval = FALSE;
/*
* Init the vars if we have em.
*/
aModuleInfo->SizeOfStruct = NS_IMAGEHLP_MODULE64_SIZE;
if (aLineInfo) {
aLineInfo->SizeOfStruct = sizeof(IMAGEHLP_LINE64);
}
/*
* Give it a go.
* It may already be loaded.
*/
retval = SymGetModuleInfo64(aProcess, aAddr, aModuleInfo);
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;
}
if (!EnsureWalkThreadReady()) {
return false;
}
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.ModuleName,
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 <string.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
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
}
#define X86_OR_PPC (defined(__i386) || defined(PPC) || defined(__ppc__))
#if X86_OR_PPC && (MOZ_STACKWALK_SUPPORTS_MACOSX || MOZ_STACKWALK_SUPPORTS_LINUX) // i386 or PPC Linux or Mac stackwalking code
MFBT_API bool
MozStackWalk(MozWalkStackCallback aCallback, uint32_t aSkipFrames,
uint32_t aMaxFrames, void* aClosure, uintptr_t aThread,
void* aPlatformData)
{
MOZ_ASSERT(!aThread);
MOZ_ASSERT(!aPlatformData);
StackWalkInitCriticalAddress();
// Get the frame pointer
void** bp;
#if defined(__i386)
__asm__("movl %%ebp, %0" : "=g"(bp));
#else
// It would be nice if this worked uniformly, but at least on i386 and
// x86_64, it stopped working with gcc 4.1, because it points to the
// end of the saved registers instead of the start.
bp = (void**)__builtin_frame_address(0);
#endif
void* stackEnd;
#if HAVE___LIBC_STACK_END
stackEnd = __libc_stack_end;
#else
stackEnd = reinterpret_cast<void*>(-1);
#endif
return FramePointerStackWalk(aCallback, aSkipFrames, 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;
int skip;
int maxFrames;
int numFrames;
bool isCriticalAbort;
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 (IsCriticalAddress(pc)) {
info->isCriticalAbort = true;
// We just want to stop the walk, so any error code will do. Using
// _URC_NORMAL_STOP would probably be the most accurate, but it is not
// defined on Android for ARM.
return _URC_FOREIGN_EXCEPTION_CAUGHT;
}
if (--info->skip < 0) {
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 bool
MozStackWalk(MozWalkStackCallback aCallback, uint32_t aSkipFrames,
uint32_t aMaxFrames, void* aClosure, uintptr_t aThread,
void* aPlatformData)
{
MOZ_ASSERT(!aThread);
MOZ_ASSERT(!aPlatformData);
StackWalkInitCriticalAddress();
unwind_info info;
info.callback = aCallback;
info.skip = aSkipFrames + 1;
info.maxFrames = aMaxFrames;
info.numFrames = 0;
info.isCriticalAbort = false;
info.closure = aClosure;
(void)_Unwind_Backtrace(unwind_callback, &info);
// We ignore the return value from _Unwind_Backtrace and instead determine
// the outcome from |info|. There are two 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.
if (info.isCriticalAbort) {
return false;
}
return info.numFrames != 0;
}
#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;
int ok = dladdr(aPC, &info);
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;
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;
return true;
}
#else // unsupported platform.
MFBT_API bool
MozStackWalk(MozWalkStackCallback aCallback, uint32_t aSkipFrames,
uint32_t aMaxFrames, void* aClosure, uintptr_t aThread,
void* aPlatformData)
{
MOZ_ASSERT(!aThread);
MOZ_ASSERT(!aPlatformData);
return false;
}
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)
namespace mozilla {
bool
FramePointerStackWalk(MozWalkStackCallback aCallback, uint32_t aSkipFrames,
uint32_t aMaxFrames, void* aClosure, void** bp,
void* aStackEnd)
{
// Stack walking code courtesy Kipp's "leaky".
int32_t skip = aSkipFrames;
uint32_t numFrames = 0;
while (bp) {
void** next = (void**)*bp;
// bp may not be a frame pointer on i386 if code was compiled with
// -fomit-frame-pointer, so do some sanity checks.
// (bp 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 bp > sp
if (next <= bp ||
next > aStackEnd ||
(uintptr_t(next) & 3)) {
break;
}
#if (defined(__ppc__) && defined(XP_MACOSX)) || defined(__powerpc64__)
// ppc mac or powerpc64 linux
void* pc = *(bp + 2);
bp += 3;
#else // i386 or powerpc32 linux
void* pc = *(bp + 1);
bp += 2;
#endif
if (IsCriticalAddress(pc)) {
return false;
}
if (--skip < 0) {
// 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, bp, aClosure);
if (aMaxFrames != 0 && numFrames == aMaxFrames) {
break;
}
}
bp = next;
}
return numFrames != 0;
}
} // namespace mozilla
#else
namespace mozilla {
MFBT_API bool
FramePointerStackWalk(MozWalkStackCallback aCallback, uint32_t aSkipFrames,
void* aClosure, void** aBp)
{
return false;
}
}
#endif
MFBT_API void
MozFormatCodeAddressDetails(char* aBuffer, uint32_t aBufferSize,
uint32_t aFrameNumber, void* aPC,
const MozCodeAddressDetails* aDetails)
{
MozFormatCodeAddress(aBuffer, aBufferSize,
aFrameNumber, aPC, aDetails->function,
aDetails->library, aDetails->loffset,
aDetails->filename, aDetails->lineno);
}
MFBT_API void
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.
snprintf(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 scripts like
// fix_{linux,macosx}_stacks.py can easily post-process.
snprintf(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.)
snprintf(aBuffer, aBufferSize,
"#%02u: ??? (???:???" ")",
aFrameNumber);
}
}
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