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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/. */
/* APIs for getting a stack trace of the current thread */
#ifndef mozilla_StackWalk_h
#define mozilla_StackWalk_h
#include "mozilla/Types.h"
#include <stdint.h>
#include <stdio.h>
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