确定非法指令错误的来源

Question

在 i386 上使用 LLVM 3.4 或更高版本构建 Thunderbird / Firefox 会导致安装阶段崩溃； amd64不会出现这个问题。在 VMware 和裸机上运行的 VM 都出现了这个问题，但我也能够在其他裸机 i386 系统上运行而没有问题。我的猜测是这可能是 LLVM 的代码生成问题，从我在其他地方听到的消息来看，这开始于 LLVM 3.3 和 3.4 之间的某个地方，但我不知道这是否真的是 LLVM 问题或相关代码中的问题Thunderbird / Firefox 的安装程序。

gmake[1]: Entering directory '/usr/ports/pobj/thunderbird-24.2.0/build-i386/mail/installer'
OMNIJAR_NAME=omni.ja \
/usr/ports/pobj/thunderbird-24.2.0/build-i386/mozilla/_virtualenv/bin/python /usr/ports/pobj/thunderbird-24.2.0/comm-esr24/mozilla/toolkit/mozapps/installer/packager.py -DMOZ_GLUE_IN_PROGRAM -DMOZ_THUNDERBIRD=1 -DOSTYPE=\"OpenBSD5\" -DOSARCH=OpenBSD -DNO_NSPR_10_SUPPORT -DAB_CD=en-US -DMOZ_APP_NAME=thunderbird -DPREF_DIR=defaults/pref -DMOZ_ENABLE_GNOME_COMPONENT=1 -DMOZ_GTK2=1 -DJAREXT= -DMOZ_NATIVE_NSPR=1 -DMOZ_NATIVE_NSS=1 -DMOZ_CHILD_PROCESS_NAME=plugin-container -DDLL_PREFIX=lib -DDLL_SUFFIX=.so.28.0 -DBIN_SUFFIX= -DBINPATH=bin \
        --format omni \
        --removals /usr/ports/pobj/thunderbird-24.2.0/comm-esr24/mail/installer/removed-files.in \
     \
     \
     \
    --optimizejars \
     \
    package-manifest ../../mozilla/dist ../../mozilla/dist/thunderbird \
    --non-resource defaults/messenger/mailViews.dat
Executing /usr/ports/pobj/thunderbird-24.2.0/build-i386/mozilla/dist/bin/xpcshell -g /usr/ports/pobj/thunderbird-24.2.0/build-i386/mozilla/dist/bin/ -a /usr/ports/pobj/thunderbird-24.2.0/build-i386/mozilla/dist/bin/ -f /usr/ports/pobj/thunderbird-24.2.0/comm-esr24/mozilla/toolkit/mozapps/installer/precompile_cache.js -e precompile_startupcache("resource://gre/");
Traceback (most recent call last):
  File "/usr/ports/pobj/thunderbird-24.2.0/comm-esr24/mozilla/toolkit/mozapps/installer/packager.py", line 375, in <module>
main()
  File "/usr/ports/pobj/thunderbird-24.2.0/comm-esr24/mozilla/toolkit/mozapps/installer/packager.py", line 367, in main
args.source, gre_path, base)
  File "/usr/ports/pobj/thunderbird-24.2.0/comm-esr24/mozilla/toolkit/mozapps/installer/packager.py", line 148, in precompile_cache
    errors.fatal('Error while running startup cache precompilation')
  File "/usr/ports/pobj/thunderbird-24.2.0/comm-esr24/mozilla/python/mozbuild/mozpack/errors.py", line 101, in fatal
self._handle(self.FATAL, msg)
  File "/usr/ports/pobj/thunderbird-24.2.0/comm-esr24/mozilla/python/mozbuild/mozpack/errors.py", line 96, in _handle
raise ErrorMessage(msg)
mozpack.errors.ErrorMessage: Error: Error while running startup cache precompilation

我正在寻求相关工具的帮助，以尝试确定此非法指令错误的来源。

Core was generated by `xpcshell'.
Program terminated with signal 4, Illegal instruction.

我使用核心文件而不是按照您指定的运行 gdb..

# egdb build-i386/mozilla/dist/bin/xpcshell build-i386/mail/installer/xpcshell.core
Python Exception <type 'exceptions.ImportError'> No module named gdb: 

warning: 
Could not load the Python gdb module from `/usr/local/share/gdb/python'.
Limited Python support is available from the _gdb module.
Suggest passing --data-directory=/path/to/gdb/data-directory.

GNU gdb (GDB) 7.6.1
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i386-unknown-openbsd5.5".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/ports/pobj/thunderbird-24.2.0/build-i386/mozilla/dist/bin/xpcshell...(no debugging symbols found)...done.
[New process 13685]
Core was generated by `xpcshell'.
Program terminated with signal 4, Illegal instruction.
#0  0x002ead4d in mozilla::BinaryPath::GetFile(char const*, nsIFile**) () from /usr/ports/pobj/thunderbird-24.2.0/build-i386/mozilla/dist/bin/libxul.so.28.0
(gdb) x/i $pc
=> 0x2ead4d <_ZN7mozilla10BinaryPath7GetFileEPKcPP7nsIFile+157>:        ud2    
(gdb) quit
# echo _ZN7mozilla10BinaryPath7GetFileEPKcPP7nsIFile+157 | c++filt
mozilla::BinaryPath::GetFile(char const*, nsIFile**)+157

Answer 1

寻求相关工具的帮助，以尝试确定此非法指令错误的来源

您的首要任务是了解什么您尝试执行的非法指令。

像这样在 GDB 下运行xpcshell：

gdb --args /usr/ports/pobj/thunderbird-24.2.0/build-i386/mozilla/dist/bin/xpcshell \
  -g /usr/ports/pobj/thunderbird-24.2.0/build-i386/mozilla/dist/bin/ -a \
  /usr/ports/pobj/thunderbird-24.2.0/build-i386/mozilla/dist/bin/ -f \
  /usr/ports/pobj/thunderbird-24.2.0/comm-esr24/mozilla/toolkit/mozapps/installer/precompile_cache.js -e \
  precompile_startupcache("resource://gre/");

(gdb) run
... GDB will stop on SIGILL
(gdb) x/i $pc

一旦你知道了非法指令是什么，你就需要弄清楚 Clang 产生它的原因。

一种可能的可能性是 ud2 指令，当 Clang 在程序中检测到 undefined behavior 时会发出该指令。