Re: gcc auto-omit-frame-pointer vs msvc longjmp
On 2011-10-20 AM 6:05, Bob Breuer wrote: We probably have a difference in build or run environment. I've double-checked with another machine and can get the same crash in longjmp when running the test executable on both WinXP and Win2k, but not on Win7. So it looks like Microsoft may have changed this "feature" somewhere between WinXP and Win7. YEES! It does crash in winxp. The msvcrt implementation of longjmp (or at least the one I'm looking at) does a ebp based access using the saved value of ebp. Here's the relevant disassembly of longjmp: 0x7801e6f3 in longjmpex () from C:\WINNT\system32\msvcrt.dll (gdb) disas Dump of assembler code for function longjmpex: 0x7801e6ef<+0>: mov0x4(%esp),%ebx => 0x7801e6f3<+4>: mov(%ebx),%ebp ... 0x7801e73d<+78>:call 0x7800bd5e ... 0x7800bd5e<+56>:push %ebx 0x7800bd5f<+57>:push %ecx 0x7800bd60<+58>:mov$0x7803dc64,%ebx => 0x7800bd65<+63>:mov0x8(%ebp),%ecx It crashes on the access of 0x8(%ebp). Those are the only 2 places where this version of longjmp touches ebp. Is it possible to force a stackframe by just adding a suitable attribute to either the setjmp function prototype, or the function which calls setjmp? and we had relevant report in ruby. http://redmine.ruby-lang.org/issues/5375 Kai, would you mind if i reopen this bug you rejected? http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49230 Bob -- Regards.
Re: gcc auto-omit-frame-pointer vs msvc longjmp
On 2011-10-21 AM 12:34, 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 tried this. it seems that problem is fixed. please apply this to trunk. although this workaround would not be needed anymore if mingw runtime provide longjmp which doesn't use _NLG_Notify. -- Regards.
Re: Problem running the libgomp testsuite
On 2012-08-20 AM 6:44, Jiří Paleček wrote: Hello, I tried to run "make check-c++" from the top directory of the source code. During the run, all of the libgomp tests run by it failed. From the log file, you can see that the gcc from the system (rather than the gcc currently built) was run: Executing on host: gcc -B/mnt/extras/src/gcc2/i686-pc-linux-gnu/libgomp/ -B/mnt/extras/src ... ... gcc: error: unrecognized command line option '-fno-diagnostics-show-caret' Other tests (like libstdc++) correctly use the currently built gcc: Executing on host: /mnt/extras/src/gcc2/host-i686-pc-linux-gnu/gcc/g++ -shared-libgcc ... ^^^ Any ideas how this could be fixed? Regards Jiri Palecek You need to modify Makefile to export CC,CXX variables so that dejagnu can execute built compiler. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51498 has similar workaround. -- Regards.
