| Message ID | CAEwic4Zey2f6fzSOAiGtyxuBnN2zSPwQCcDdTDdL8-DOiqC2GQ@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
Hi, all
It seems that gcc's auto-omit-frame-pointer has other problems.
The example is from mingw bug tracker:
http://sourceforge.net/tracker/?func=detail&aid=3426555&group_id=2435&atid=102435
g++ -O3 main.cpp running will crash.
g++ -O2 main.cpp running no crash.
g++ -O3 -fno-omit-frame-pointer running no crash.
I don't know in the end which optimize option defaultly contains
this switch "-fomit-frame-pointer" on i686-pc-mingw32 or x86_64-w64-mingw32?
于 2011/10/22 13:13, xunxun 写道: > Hi, all > > It seems that gcc's auto-omit-frame-pointer has other problems. > > The example is from mingw bug tracker: > http://sourceforge.net/tracker/?func=detail&aid=3426555&group_id=2435&atid=102435 > > g++ -O3 main.cpp running will crash. > g++ -O2 main.cpp running no crash. > g++ -O3 -fno-omit-frame-pointer running no crash. > > I don't know in the end which optimize option defaultly contains > this switch "-fomit-frame-pointer" on i686-pc-mingw32 or > x86_64-w64-mingw32? > It crashes on Win7.
2011/10/22 xunxun <xunxun1982@gmail.com>: > 于 2011/10/22 13:13, xunxun 写道: >> >> Hi, all >> >> It seems that gcc's auto-omit-frame-pointer has other problems. >> >> The example is from mingw bug tracker: >> http://sourceforge.net/tracker/?func=detail&aid=3426555&group_id=2435&atid=102435 >> >> g++ -O3 main.cpp running will crash. >> g++ -O2 main.cpp running no crash. >> g++ -O3 -fno-omit-frame-pointer running no crash. >> >> I don't know in the end which optimize option defaultly contains this >> switch "-fomit-frame-pointer" on i686-pc-mingw32 or x86_64-w64-mingw32? >> > It crashes on Win7. Well, this issue isn't related to this thread. It is more related to dw2 and SjLj used. For toolchains using dw2 exception mechanism, you will see this crash. By using SjLj you won't (thanks for checking this). This shows indeed my strong concerns about dw2 exception mechanism for 32-bit Windows targets. The implementation depends too much on code-patterns and is therefore a bit inconsitant. Secondly it causes harm if you try to throw exceptions over VC generated code. So I would strongly recomment to use the slower, but more reliable SjLj throwing mechanism on Windows 32-bit. Regards, Kai
On 2011-10-20 23:34, Kai Tietz wrote: > Hi, > > For trunk-version I have a tentative patch for this issue. On 4.6.x > and older branches this doesn't work, as here we can't differenciate > that easy between ms- and sysv-abi. > > But could somebody give this patch a try? > > Regards, > Kai > > ChangeLog > > * config/i386/i386.c (ix86_frame_pointer_required): Enforce use of > frame-pointer for 32-bit ms-abi, if setjmp is used. > > Index: i386.c > =================================================================== > --- i386.c (revision 180099) > +++ i386.c (working copy) > @@ -8391,6 +8391,10 @@ > if (SUBTARGET_FRAME_POINTER_REQUIRED) > return true; > > + /* For older 32-bit runtimes setjmp requires valid frame-pointer. */ > + if (TARGET_32BIT_MS_ABI&& cfun->calls_setjmp) > + return true; > + > /* In ix86_option_override_internal, TARGET_OMIT_LEAF_FRAME_POINTER > turns off the frame pointer by default. Turn it back on now if > we've not got a leaf function. */ > I just see two related links about this issue: see: http://stackoverflow.com/questions/5887552/setjmp-and-omit-frame-pointer and http://connect.microsoft.com/VisualStudio/feedback/details/666704/visual-c-generates-incorrect-code-with-omit-frame-pointer-and-setjmp I'm not sure microsoft has fix this issue. asmwarrior ollydbg from codeblocks' forum
Kai Tietz wrote: > Hi, > > For trunk-version I have a tentative patch for this issue. On 4.6.x > and older branches this doesn't work, as here we can't differenciate > that easy between ms- and sysv-abi. > > But could somebody give this patch a try? > > Regards, > Kai > > ChangeLog > > * config/i386/i386.c (ix86_frame_pointer_required): Enforce use of > frame-pointer for 32-bit ms-abi, if setjmp is used. > > Index: i386.c > =================================================================== > --- i386.c (revision 180099) > +++ i386.c (working copy) > @@ -8391,6 +8391,10 @@ > if (SUBTARGET_FRAME_POINTER_REQUIRED) > return true; > > + /* For older 32-bit runtimes setjmp requires valid frame-pointer. */ > + if (TARGET_32BIT_MS_ABI && cfun->calls_setjmp) > + return true; > + > /* In ix86_option_override_internal, TARGET_OMIT_LEAF_FRAME_POINTER > turns off the frame pointer by default. Turn it back on now if > we've not got a leaf function. */ > For a gcc 4.7 snapshot, this does fix the longjmp problem that I encountered. So aside from specifying -fno-omit-frame-pointer for affected files, what can be done for 4.6? Bob
Index: i386.c =================================================================== --- i386.c (revision 180099) +++ i386.c (working copy) @@ -8391,6 +8391,10 @@ if (SUBTARGET_FRAME_POINTER_REQUIRED) return true; + /* For older 32-bit runtimes setjmp requires valid frame-pointer. */ + if (TARGET_32BIT_MS_ABI && cfun->calls_setjmp) + return true; + /* In ix86_option_override_internal, TARGET_OMIT_LEAF_FRAME_POINTER turns off the frame pointer by default. Turn it back on now if we've not got a leaf function. */
Hi, For trunk-version I have a tentative patch for this issue. On 4.6.x and older branches this doesn't work, as here we can't differenciate that easy between ms- and sysv-abi. But could somebody give this patch a try? Regards, Kai ChangeLog * config/i386/i386.c (ix86_frame_pointer_required): Enforce use of frame-pointer for 32-bit ms-abi, if setjmp is used.