diff -r 000000000000 -r 6474c204b198 xpcom/base/nsStackWalk.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/base/nsStackWalk.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,125 @@
+/* vim: set shiftwidth=4 tabstop=8 autoindent cindent expandtab: */
+/* 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 */
+
+#ifndef nsStackWalk_h_
+#define nsStackWalk_h_
+
+/* WARNING: This file is intended to be included from C or C++ files. */
+
+#include "nscore.h"
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// aSP will be the best approximation possible of what the stack pointer will be
+// pointing to when the execution returns to executing that at that PC.
+// If no approximation can be made it will be nullptr.
+typedef void
+(* NS_WalkStackCallback)(void *aPC, void *aSP, void *aClosure);
+
+/**
+ * Call aCallback for the C/C++ stack frames on the current thread, from
+ * the caller of NS_StackWalk 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
+ *                     NS_StackWalk.
+ * @param aMaxFrames   Maximum number of frames to trace.  0 means no limit.
+ * @param aClosure     Caller-supplied data passed through to aCallback.
+ * @param aThread      The thread for which the stack is to be retrieved.
+ *                     Passing null causes us to walk the stack of the
+ *                     current thread. On Windows, this is a thread HANDLE.
+ *                     It is currently not supported on any other platform.
+ * @param aPlatformData Platform specific data that can help in walking the
+ *                      stack, this should be nullptr unless you really know
+ *                      what you're doing! This needs to be a pointer to a
+ *                      CONTEXT on Windows and should not be passed on other
+ *                      platforms.
+ *
+ * Return values:
+ * - NS_ERROR_NOT_IMPLEMENTED.  Occurs on platforms where it is unimplemented.
+ *
+ * - NS_ERROR_UNEXPECTED.  Occurs when the stack indicates that the thread
+ *   is in a very dangerous situation (e.g., holding sem_pool_lock in Mac OS X
+ *   pthreads code).  Callers should then bail out immediately.
+ *
+ * - NS_ERROR_FAILURE.  Occurs when stack walking completely failed, i.e.
+ *   aCallback was never called.
+ *
+ * - NS_OK.  Occurs when stack walking succeeded, i.e. aCallback was called at
+ *   least once (and there was no need to exit with NS_ERROR_UNEXPECTED).
+ *
+ * May skip some stack frames due to compiler optimizations or code
+ * generation.
+ */
+XPCOM_API(nsresult)
+NS_StackWalk(NS_WalkStackCallback aCallback, uint32_t aSkipFrames,
+             uint32_t aMaxFrames, void *aClosure, uintptr_t aThread,
+             void *aPlatformData);
+
+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;
+} nsCodeAddressDetails;
+
+/**
+ * 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.
+ */
+XPCOM_API(nsresult)
+NS_DescribeCodeAddress(void *aPC, nsCodeAddressDetails *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.
+ *
+ * @param aPC         The code address.
+ * @param aDetails    The value filled in by NS_DescribeCodeAddress(aPC).
+ * @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.
+ */
+XPCOM_API(nsresult)
+NS_FormatCodeAddressDetails(void *aPC, const nsCodeAddressDetails *aDetails,
+                            char *aBuffer, uint32_t aBufferSize);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* !defined(nsStackWalk_h_) */