mozglue/misc/StackWalk.h
author Gerald Squelart <gsquelart@mozilla.com>
Thu, 04 Jul 2019 04:38:16 +0000
changeset 481213 8fed7bc35767fdfab4bac0908ae9b21c08f49e1f
parent 454520 5f4630838d46dd81dadb13220a4af0da9e23a619
child 489545 9a33b94c2471e4aea327866d4c5dd2d04e18f938
permissions -rw-r--r--
Bug 1559000 - mozglue's AutoProfilerLabel doesn't need to know about ProfilingStack - r=mstange `ProfilingStack*` happens to be the information that the current Gecko Profiler entry function wants to forward to the exit function, but AutoProfilerLabel does not really need to know about that. Changing it to `void*`, so that we can later use different entry/exit functions that use different context types. Differential Revision: https://phabricator.services.mozilla.com/D34806

/* -*- 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>

/**
 * 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 aSkipFrames  Number of initial frames to skip.  0 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, uint32_t aSkipFrames,
                           uint32_t aMaxFrames, void* aClosure);

#if defined(_WIN32) && (defined(_M_IX86) || defined(_M_AMD64) || \
                        defined(_M_IA64) || defined(_M_ARM64))

#  include <windows.h>

#  define MOZ_STACKWALK_SUPPORTS_WINDOWS 1

/**
 * Like MozStackWalk, but walks the stack for another thread.
 * Call aCallback for each stack frame on the current thread, from
 * the caller of MozStackWalk to main (or above).
 *
 * @param aCallback    Same as for MozStackWalk().
 * @param aSkipFrames  Same as for MozStackWalk().
 * @param aMaxFrames   Same as for MozStackWalk().
 * @param aClosure     Same as for MozStackWalk().
 * @param aThread      The handle of the thread whose stack is to be walked.
 *                     If 0, walks the current thread.
 * @param aContext     A CONTEXT, presumably obtained with GetThreadContext()
 *                     after suspending the thread with SuspendThread(). If
 *                     null, the CONTEXT will be re-obtained.
 */
MFBT_API void MozStackWalkThread(MozWalkStackCallback aCallback,
                                 uint32_t aSkipFrames, uint32_t aMaxFrames,
                                 void* aClosure, HANDLE aThread,
                                 CONTEXT* aContext);

#else

#  define MOZ_STACKWALK_SUPPORTS_WINDOWS 0

#endif

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.
 */
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);

/**
 * 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).
 */
MFBT_API void MozFormatCodeAddressDetails(
    char* aBuffer, uint32_t aBufferSize, uint32_t aFrameNumber, void* aPC,
    const MozCodeAddressDetails* aDetails);

namespace mozilla {

MFBT_API void FramePointerStackWalk(MozWalkStackCallback aCallback,
                                    uint32_t aSkipFrames, uint32_t aMaxFrames,
                                    void* aClosure, void** aBp,
                                    void* aStackEnd);

}  // namespace mozilla

#endif