/* -*- 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/. */ /* APIs for getting a stack trace of the current thread */ #ifndef mozilla_StackWalk_h #define mozilla_StackWalk_h #include "mozilla/Types.h" #include #include MOZ_BEGIN_EXTERN_C /** * Returns the position of the Program Counter for the caller of the current * function. This is meant to be used to feed the aFirstFramePC argument to * MozStackWalk or MozWalkTheStack*, and should be used in the last function * that should be skipped in the trace, and passed down to MozStackWalk or * MozWalkTheStack*, through any intermediaries. * * THIS DOES NOT 100% RELIABLY GIVE THE CALLER PC, but marking functions * calling this macro with MOZ_NEVER_INLINE gets us close. In cases it doesn't * give the caller's PC, it may give the caller of the caller, or its caller, * etc. depending on tail call optimization. * * Past versions of stackwalking relied on passing a constant number of frames * to skip to MozStackWalk or MozWalkTheStack, which fell short in more cases * (inlining of intermediaries, tail call optimization). */ #define CallerPC() __builtin_extract_return_addr(__builtin_return_address(0)) /** * The callback for MozStackWalk and MozStackWalkThread. * * @param aFrameNumber The frame number (starts at 1, not 0). * @param aPC The program counter value. * @param aSP The best approximation possible of what the stack * pointer will be pointing to when the execution returns * to executing that at aPC. If no approximation can * be made it will be nullptr. * @param aClosure Extra data passed in from MozStackWalk() or * MozStackWalkThread(). */ typedef void (*MozWalkStackCallback)(uint32_t aFrameNumber, void* aPC, void* aSP, void* aClosure); /** * Call aCallback for each stack frame on the current thread, from * the caller of MozStackWalk to main (or above). * * @param aCallback Callback function, called once per frame. * @param aFirstFramePC Position of the Program Counter where the trace * starts from. All frames seen before reaching that * address are skipped. Nullptr means that the first * callback will be for the caller of MozStackWalk. * @param aMaxFrames Maximum number of frames to trace. 0 means no limit. * @param aClosure Caller-supplied data passed through to aCallback. * * May skip some stack frames due to compiler optimizations or code * generation. */ MFBT_API void MozStackWalk(MozWalkStackCallback aCallback, const void* aFirstFramePC, uint32_t aMaxFrames, void* aClosure); typedef struct { /* * The name of the shared library or executable containing an * address and the address's offset within that library, or empty * string and zero if unknown. */ char library[256]; ptrdiff_t loffset; /* * The name of the file name and line number of the code * corresponding to the address, or empty string and zero if * unknown. */ char filename[256]; unsigned long lineno; /* * The name of the function containing an address and the address's * offset within that function, or empty string and zero if unknown. */ char function[256]; ptrdiff_t foffset; } MozCodeAddressDetails; /** * For a given pointer to code, fill in the pieces of information used * when printing a stack trace. * * @param aPC The code address. * @param aDetails A structure to be filled in with the result. */ MFBT_API bool MozDescribeCodeAddress(void* aPC, MozCodeAddressDetails* aDetails); /** * Format the information about a code address in a format suitable for * stack traces on the current platform. When available, this string * should contain the function name, source file, and line number. When * these are not available, library and offset should be reported, if * possible. * * Note that this output is parsed by several scripts including the fix*.py and * make-tree.pl scripts in tools/rb/. It should only be change with care, and * in conjunction with those scripts. * * @param aBuffer A string to be filled in with the description. * The string will always be null-terminated. * @param aBufferSize The size, in bytes, of aBuffer, including * room for the terminating null. If the information * to be printed would be larger than aBuffer, it * will be truncated so that aBuffer[aBufferSize-1] * is the terminating null. * @param aFrameNumber The frame number. * @param aPC The code address. * @param aFunction The function name. Possibly null or the empty string. * @param aLibrary The library name. Possibly null or the empty string. * @param aLOffset The library offset. * @param aFileName The filename. Possibly null or the empty string. * @param aLineNo The line number. Possibly zero. * @return The minimum number of characters necessary to format * the frame information, without the terminating null. * The buffer will have been truncated if the returned * value is greater than aBufferSize-1. */ 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); /** * Format the information about a code address in the same fashion as * MozFormatCodeAddress. * * @param aBuffer A string to be filled in with the description. * The string will always be null-terminated. * @param aBufferSize The size, in bytes, of aBuffer, including * room for the terminating null. If the information * to be printed would be larger than aBuffer, it * will be truncated so that aBuffer[aBufferSize-1] * is the terminating null. * @param aFrameNumber The frame number. * @param aPC The code address. * @param aDetails The value filled in by MozDescribeCodeAddress(aPC). * @return The minimum number of characters necessary to format * the frame information, without the terminating null. * The buffer will have been truncated if the returned * value is greater than aBufferSize-1. */ MFBT_API int MozFormatCodeAddressDetails(char* aBuffer, uint32_t aBufferSize, uint32_t aFrameNumber, void* aPC, const MozCodeAddressDetails* aDetails); #ifdef __cplusplus # define FRAMES_DEFAULT = 0 #else # define FRAMES_DEFAULT #endif /** * Walk the stack and print the stack trace to the given stream. * * @param aStream A stdio stream. * @param aFirstFramePC Position of the Program Counter where the trace * starts from. All frames seen before reaching that * address are skipped. Nullptr means that the first * callback will be for the caller of MozWalkTheStack. * @param aMaxFrames Maximum number of frames to trace. 0 means no limit. */ MFBT_API void MozWalkTheStack(FILE* aStream, const void* aFirstFramePC FRAMES_DEFAULT, uint32_t aMaxFrames FRAMES_DEFAULT); /** * Walk the stack and send each stack trace line to a callback writer. * Each line string is null terminated but doesn't contain a '\n' character. * * @param aWriter The callback. * @param aFirstFramePC Position of the Program Counter where the trace * starts from. All frames seen before reaching that * address are skipped. Nullptr means that the first * callback will be for the caller of * MozWalkTheStackWithWriter. * @param aMaxFrames Maximum number of frames to trace. 0 means no limit. */ MFBT_API void MozWalkTheStackWithWriter( void (*aWriter)(const char*), const void* aFirstFramePC FRAMES_DEFAULT, uint32_t aMaxFrames FRAMES_DEFAULT); #undef FRAMES_DEFAULT MOZ_END_EXTERN_C #ifdef __cplusplus namespace mozilla { MFBT_API void FramePointerStackWalk(MozWalkStackCallback aCallback, uint32_t aMaxFrames, void* aClosure, void** aBp, void* aStackEnd); # if defined(XP_LINUX) || defined(XP_FREEBSD) MFBT_API void DemangleSymbol(const char* aSymbol, char* aBuffer, int aBufLen); # endif } // namespace mozilla #endif #endif