1*debug.txt* For Vim version 8.1. Last change: 2017 Jul 15 2 3 4 VIM REFERENCE MANUAL by Bram Moolenaar 5 6 7Debugging Vim *debug-vim* 8 9This is for debugging Vim itself, when it doesn't work properly. 10For debugging Vim scripts, functions, etc. see |debug-scripts| 11 121. Location of a crash, using gcc and gdb |debug-gcc| 132. Locating memory leaks |debug-leaks| 143. Windows Bug Reporting |debug-win32| 15 16============================================================================== 17 181. Location of a crash, using gcc and gdb *debug-gcc* *gdb* 19 20When Vim crashes in one of the test files, and you are using gcc for 21compilation, here is what you can do to find out exactly where Vim crashes. 22This also applies when using the MingW tools. 23 241. Compile Vim with the "-g" option (there is a line in the src/Makefile for 25 this, which you can uncomment). Also make sure "strip" is disabled (do not 26 install it, or use the line "STRIP = /bin/true"). 27 282. Execute these commands (replace "11" with the test that fails): > 29 cd testdir 30 gdb ../vim 31 run -u unix.vim -U NONE -s dotest.in test11.in 32 333. Check where Vim crashes, gdb should give a message for this. 34 354. Get a stack trace from gdb with this command: > 36 where 37< You can check out different places in the stack trace with: > 38 frame 3 39< Replace "3" with one of the numbers in the stack trace. 40 41============================================================================== 42 432. Locating memory leaks *debug-leaks* *valgrind* 44 45If you suspect Vim is leaking memory and you are using Linux, the valgrind 46tool is very useful to pinpoint memory leaks. 47 48First of all, build Vim with EXITFREE defined. Search for this in MAKEFILE 49and uncomment the line. 50 51Use this command to start Vim: 52> 53 valgrind --log-file=valgrind.log --leak-check=full ./vim 54 55Note: Vim will run much slower. If your .vimrc is big or you have several 56plugins you need to be patient for startup, or run with the "--clean" 57argument. 58 59There are often a few leaks from libraries, such as getpwuid() and 60XtVaAppCreateShell(). Those are unavoidable. The number of bytes should be 61very small a Kbyte or less. 62 63============================================================================== 64 653. Windows Bug Reporting *debug-win32* 66 67If the Windows version of Vim crashes in a reproducible manner, you can take 68some steps to provide a useful bug report. 69 70 713.1 GENERIC ~ 72 73You must obtain the debugger symbols (PDB) file for your executable: gvim.pdb 74for gvim.exe, or vim.pdb for vim.exe. The PDB should be available from the 75same place that you obtained the executable. Be sure to use the PDB that 76matches the EXE (same date). 77 78If you built the executable yourself with the Microsoft Visual C++ compiler, 79then the PDB was built with the EXE. 80 81If you have Visual Studio, use that instead of the VC Toolkit and WinDbg. 82 83For other compilers, you should always use the corresponding debugger: TD for 84a Vim executable compiled with the Borland compiler; gdb (see above 85|debug-gcc|) for the Cygwin and MinGW compilers. 86 87 88 *debug-vs2005* 893.2 Debugging Vim crashes with Visual Studio 2005/Visual C++ 2005 Express ~ 90 91First launch vim.exe or gvim.exe and then launch Visual Studio. (If you don't 92have Visual Studio, follow the instructions at |get-ms-debuggers| to obtain a 93free copy of Visual C++ 2005 Express Edition.) 94 95On the Tools menu, click Attach to Process. Choose the Vim process. 96 97In Vim, reproduce the crash. A dialog will appear in Visual Studio, telling 98you about the unhandled exception in the Vim process. Click Break to break 99into the process. 100 101Visual Studio will pop up another dialog, telling you that no symbols are 102loaded and that the source code cannot be displayed. Click OK. 103 104Several windows will open. Right-click in the Call Stack window. Choose Load 105Symbols. The Find Symbols dialog will open, looking for (g)vim.pdb. Navigate 106to the directory where you have the PDB file and click Open. 107 108At this point, you should have a full call stack with vim function names and 109line numbers. Double-click one of the lines and the Find Source dialog will 110appear. Navigate to the directory where the Vim source is (if you have it.) 111 112If you don't know how to debug this any further, follow the instructions 113at ":help bug-reports". Paste the call stack into the bug report. 114 115If you have a non-free version of Visual Studio, you can save a minidump via 116the Debug menu and send it with the bug report. A minidump is a small file 117(<100KB), which contains information about the state of your process. 118Visual C++ 2005 Express Edition cannot save minidumps and it cannot be 119installed as a just-in-time debugger. Use WinDbg, |debug-windbg|, if you 120need to save minidumps or you want a just-in-time (postmortem) debugger. 121 122 *debug-windbg* 1233.3 Debugging Vim crashes with WinDbg ~ 124 125See |get-ms-debuggers| to obtain a copy of WinDbg. 126 127As with the Visual Studio IDE, you can attach WinDbg to a running Vim process. 128You can also have your system automatically invoke WinDbg as a postmortem 129debugger. To set WinDbg as your postmortem debugger, run "windbg -I". 130 131To attach WinDbg to a running Vim process, launch WinDbg. On the File menu, 132choose Attach to a Process. Select the Vim process and click OK. 133 134At this point, choose Symbol File Path on the File menu, and add the folder 135containing your Vim PDB to the sympath. If you have Vim source available, 136use Source File Path on the File menu. You can now open source files in WinDbg 137and set breakpoints, if you like. Reproduce your crash. WinDbg should open the 138source file at the point of the crash. Using the View menu, you can examine 139the call stack, local variables, watch windows, and so on. 140 141If WinDbg is your postmortem debugger, you do not need to attach WinDbg to 142your Vim process. Simply reproduce the crash and WinDbg will launch 143automatically. As above, set the Symbol File Path and the Source File Path. 144 145To save a minidump, type the following at the WinDbg command line: > 146 .dump vim.dmp 147< 148 *debug-minidump* 1493.4 Opening a Minidump ~ 150 151If you have a minidump file, you can open it in Visual Studio or in WinDbg. 152 153In Visual Studio 2005: on the File menu, choose Open, then Project/Solution. 154Navigate to the .dmp file and open it. Now press F5 to invoke the debugger. 155Follow the instructions in |debug-vs2005| to set the Symbol File Path. 156 157In WinDbg: choose Open Crash Dump on the File menu. Follow the instructions in 158|debug-windbg| to set the Symbol File Path. 159 160 *get-ms-debuggers* 1613.5 Obtaining Microsoft Debugging Tools ~ 162 163The Debugging Tools for Windows (including WinDbg) can be downloaded from 164 http://www.microsoft.com/whdc/devtools/debugging/default.mspx 165This includes the WinDbg debugger. 166 167Visual C++ 2005 Express Edition can be downloaded for free from: 168 http://msdn.microsoft.com/vstudio/express/visualC/default.aspx 169 170========================================================================= 171 vim:tw=78:ts=8:noet:ft=help:norl: 172