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      1 /**************************************************************************
      2  *
      3  * Copyright 2009 VMware, Inc.
      4  * All Rights Reserved.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the
      8  * "Software"), to deal in the Software without restriction, including
      9  * without limitation the rights to use, copy, modify, merge, publish,
     10  * distribute, sub license, and/or sell copies of the Software, and to
     11  * permit persons to whom the Software is furnished to do so, subject to
     12  * the following conditions:
     13  *
     14  * The above copyright notice and this permission notice (including the
     15  * next paragraph) shall be included in all copies or substantial portions
     16  * of the Software.
     17  *
     18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
     21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
     22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
     23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
     24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     25  *
     26  **************************************************************************/
     27 
     28 /**
     29  * @file
     30  * Stack backtracing.
     31  *
     32  * @author Jose Fonseca <jfonseca (at) vmware.com>
     33  */
     34 
     35 #include "u_debug.h"
     36 #include "u_debug_symbol.h"
     37 #include "u_debug_stack.h"
     38 
     39 
     40 void
     41 debug_backtrace_capture(struct debug_stack_frame *backtrace,
     42                         unsigned start_frame,
     43                         unsigned nr_frames)
     44 {
     45    const void **frame_pointer = NULL;
     46    unsigned i = 0;
     47 
     48    if(!nr_frames)
     49       return;
     50 
     51 #if defined(PIPE_CC_GCC) && defined(PIPE_ARCH_X86)
     52    __asm__ __volatile__("mov (%%ebp),%0": "=r" (frame_pointer));
     53    frame_pointer = (const void **)frame_pointer[0];
     54 #elif defined(PIPE_CC_GCC)
     55    frame_pointer = ((const void **)__builtin_frame_address(1));
     56 #elif defined(PIPE_CC_MSVC) && defined(PIPE_ARCH_X86)
     57    __asm {
     58       mov frame_pointer, ebp
     59    }
     60    frame_pointer = (const void **)frame_pointer[0];
     61 #else
     62    frame_pointer = NULL;
     63 #endif
     64 
     65 
     66 #ifdef PIPE_ARCH_X86
     67    while(nr_frames) {
     68       const void **next_frame_pointer;
     69 
     70       if(!frame_pointer)
     71          break;
     72 
     73       if(start_frame)
     74          --start_frame;
     75       else {
     76          backtrace[i++].function = frame_pointer[1];
     77          --nr_frames;
     78       }
     79 
     80       next_frame_pointer = (const void **)frame_pointer[0];
     81 
     82       /* Limit the stack walk to avoid referencing undefined memory */
     83       if((uintptr_t)next_frame_pointer <= (uintptr_t)frame_pointer ||
     84          (uintptr_t)next_frame_pointer > (uintptr_t)frame_pointer + 64*1024)
     85          break;
     86 
     87       frame_pointer = next_frame_pointer;
     88    }
     89 #else
     90    (void) frame_pointer;
     91 #endif
     92 
     93    while(nr_frames) {
     94       backtrace[i++].function = NULL;
     95       --nr_frames;
     96    }
     97 }
     98 
     99 
    100 void
    101 debug_backtrace_dump(const struct debug_stack_frame *backtrace,
    102                      unsigned nr_frames)
    103 {
    104    unsigned i;
    105 
    106    for(i = 0; i < nr_frames; ++i) {
    107       if(!backtrace[i].function)
    108          break;
    109       debug_symbol_print(backtrace[i].function);
    110    }
    111 }
    112 
    113