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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