1<?php $this->extends('layout.php', ['title' => 'Generating a backtrace on Windows']) ?> 2 3<?php $this->start('content') ?> 4 5<p> 6<a href="/bugs-generating-backtrace.php">Unix</a> | <strong>Windows</strong> 7</p> 8 9<h1>Generating a backtrace, <u>with</u> a compiler, on Windows</h1> 10 11<p>You'll need to install MS Visual Studio 2008, 2012 or later. You'll also need to</p> 12<ul> 13 <li>either download the debug-pack for your PHP version from <a href="https://windows.php.net/download/">windows.php.net/download</a></li> 14 <li>or compile your own PHP with <code>--enable-dbg-pack</code> or <code>--enable-debug</code></li> 15</ul> 16 17<p>If you downloaded the debug-pack from the snaps site, extract it into your 18PHP directory and be sure to put the PDB files that belong to the extensions 19into your extension directory.</p> 20 21<p>If you compile PHP by your own, you can also use a newer version of MSVC.</p> 22 23<p>When PHP crashes, click <em>Cancel</em> to debug the process. Now MSVC starts 24up in <em>Debug View</em>. If you don't already see the call stack, go into the 25<em>View</em> menu and choose <em>Debug Windows</em> → <em>Call Stack</em>.</p> 26 27<p>You'll now see something similar to the following lines, this is the backtrace:</p> 28<pre><code> 29_efree(void * 0x00000000) line 286 + 3 bytes 30zif_http_test(int 0, _zval_struct * 0x007bc3b0, _zval_struct * * 0x00000000, _zval_struct * 0x00000000, int 0, void * * * 0x00792cd0) line 1685 + 8 bytes 31zend_do_fcall_common_helper_SPEC(_zend_execute_data * 0x0012fd6c, void * * * 0x00792cd0) line 188 + 95 bytes 32ZEND_DO_FCALL_SPEC_CONST_HANDLER(_zend_execute_data * 0x0012fd6c, void * * * 0x00792cd0) line 1578 + 13 bytes 33execute(_zend_op_array * 0x007bc880, void * * * 0x00792cd0) line 88 + 13 bytes 34zend_eval_string(char * 0x00793bce, _zval_struct * 0x00000000, char * 0x00404588 tring', void * * * 0x00792cd0) line 1056 + 14 bytes 35zend_eval_string_ex(char * 0x00793bce, _zval_struct * 0x00000000, char * 0x00404588 tring', int 1, void * * * 0x00792cd0) line 1090 + 21 bytes 36main(int 3, char * * 0x00793ba8) line 1078 + 23 bytes 37PHP! mainCRTStartup + 227 bytes 38KERNEL32! 77e81af6() 39</code></pre> 40 41<h1>Generating backtrace, <u>without</u> compiler, on Windows</h1> 42 43<p>Generating a backtrace without compiler is usually a two step process:</p> 44<ul> 45<li>Generate a crash dump file (.dmp)</li> 46<li>Analyze the crash dump file to get a stack backtrace</li> 47</ul> 48<p>There are several solutions for either step; in the following we describe one solution each.</p> 49 50<h2>Use ProcDump to generate crash dump files</h2> 51 52<p>Download <a href="https://docs.microsoft.com/en-us/sysinternals/downloads/procdump">ProcDump</a>, 53and register it as the Just-in-Time (AeDebug) debugger:</p> 54<pre><code>procdump -ma -i C:\dumps</code></pre> 55<p>Use any suitable folder to store the crash dump files instead of <code>C:\dumps</code>. 56Whenever a process crashes, a crash dump file will be written to the specified folder.</p> 57 58<h2>Use Debug Diagnostic Tool to analyze the crash dump</h2> 59 60<ul> 61<li>Download and install <a 62href="https://www.microsoft.com/en-us/download/details.aspx?id=58210">Debug Diagnostic Tool</a></li> 63<li><a href="https://windows.php.net/downloads/">Download</a> and unpack the PHP debug pack corresponding to the PHP version you are running</li> 64<li>Start the Debug Diagnostic Tool</li> 65<li>Add the path to the unpacked PHP debug pack as symbol search path in the settings</li> 66<li>Press "add data file" and select the crash dump file formerly generated</li> 67<li>Select "default analysis"</li> 68<li>Press "start analysis"</li> 69</ul> 70<p>After the analysis has finished, the DebugDiag Analysis Report opens in Internet 71Explorer; the relevant part of that report is the stack backtrace, which looks similar 72to the following:</p> 73<p><img src="/images/backtrace-images-win32/backtrace.jpg" alt="Debug report backtrace screenshot"></a></p> 74 75<?php $this->end('content') ?> 76
