[Bug debug/50544] New: Wrong esp offset in debug infos for functions that call stdcall functions
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50544 Bug #: 50544 Summary: Wrong esp offset in debug infos for functions that call stdcall functions Classification: Unclassified Product: gcc Version: 4.6.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: debug AssignedTo: unassig...@gcc.gnu.org ReportedBy: bernhardl...@googlemail.com Created attachment 25372 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25372 compile with -g -O2 In the attached program, f2 disassambles to this: 0x08048400 <+0>: sub$0x1c,%esp 0x08048403 <+3>: mov0x8049708,%eax 0x08048408 <+8>: mov%eax,(%esp) 0x0804840b <+11>:call 0x80483e0 0x08048410 <+16>:sub$0x4,%esp 0x08048413 <+19>:add$0x1c,%esp 0x08048416 <+22>:ret If one places a breakpoint at 0x08048410 the stack looks like this: Breakpoint 1, 0x08048410 in f2 () at asdf.c:20 20 f(x); (gdb) bt #0 0x08048410 in f2 () at asdf.c:20 #1 0x08048420 in ?? () #2 0x4dedd413 in __libc_start_main (main=0x8048310 , argc=1, ubp_av=0xb724, init=0x8048420 <__libc_csu_init>, fini=0x8048490 <__libc_csu_fini>, rtld_fini=0x4deb1dd0 <_dl_fini>, stack_end=0xb71c) at libc-start.c:226 #3 0x08048341 in _start () For 0x08048413, it looks as it should: #0 f2 () at asdf.c:22 #1 0x0804831b in main (argc=1, argv=0xb724) at asdf.c:27 I would guess that the frame adjustment DWARF op is not emitted for the instruction at 0x08048410. Normally this wouldn't be much of a problem, but wine hits this sometimes with the way it sets up windows exceptions, which makes this very annoying. gcc version is Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/libexec/gcc/i686-redhat-linux/4.6.1/lto-wrapper Target: i686-redhat-linux Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --enable-languages=c,c++,objc,obj-c++,java,fortran,ada,go,lto --enable-plugin --enable-java-awt=gtk --disable-dssi --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-1.5.0.0/jre --enable-libgcj-multifile --enable-java-maintainer-mode --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --disable-libjava-multilib --with-ppl --with-cloog --with-tune=generic --with-arch=i686 --build=i686-redhat-linux Thread model: posix gcc version 4.6.1 20110804 (Red Hat 4.6.1-7) (GCC)
[Bug target/44060] New: miscompilation with -Os on x86
Gcc 4.5 miscompiles the following code:
char buf[1024];
void add_input_file(int file)
{
(*((int **)&buf))[0] = file;
}
it results in this asm:
Disassembly of section .text:
:
0: c3 ret
The file argument is completly ignored.
gcc4.4 does the right thing:
Disassembly of section .text:
:
0: a1 00 00 00 00 mov0x0,%eax
5: 8b 54 24 04 mov0x4(%esp),%edx
9: 89 10 mov%edx,(%eax)
b: c3 ret
The command used to produce this output was i486-openwrt-linux-gcc -c asdf.c
-fomit-frame-pointer -Os -o asdf2.o
Openwrt adds a number of patches to gcc, they can be seen here:
https://dev.openwrt.org/browser/trunk/toolchain/gcc/patches/4.5.0
None of them should interfer with the codegeneration for x86.
The problem doesn't seem to happen with the mips target.
This is the output of gcc -v:
Using built-in specs.
COLLECT_GCC=../staging_dir/toolchain-i386_gcc-4.5.0_uClibc-0.9.30.3/usr/bin/i486-openwrt-linux-gcc
COLLECT_LTO_WRAPPER=/home/asdf/openwrt/trunk/staging_dir/toolchain-i386_gcc-4.5.0_uClibc-0.9.30.3/usr/libexec/gcc/i486-openwrt-linux-uclibc/4.5.0/lto-wrapper
Target: i486-openwrt-linux-uclibc
Configured with:
/home/asdf/openwrt/trunk/build_dir/toolchain-i386_gcc-4.5.0_uClibc-0.9.30.3/gcc-4.5.0/configure
--prefix=/home/asdf/openwrt/trunk/staging_dir/toolchain-i386_gcc-4.5.0_uClibc-0.9.30.3/usr
--build=i586-redhat-linux --host=i586-redhat-linux
--target=i486-openwrt-linux-uclibc --with-gnu-ld --enable-target-optspace
--disable-libgomp --disable-libmudflap --disable-multilib --disable-nls
--with-ppl --with-cloog --with-host-libstdcxx=-lstdc++
--with-gmp=/home/asdf/openwrt/trunk/staging_dir/host
--with-mpfr=/home/asdf/openwrt/trunk/staging_dir/host --disable-decimal-float
--disable-libssp --disable-__cxa_atexit --enable-languages=c,c++
--enable-shared --enable-threads
--with-slibdir=/home/asdf/openwrt/trunk/staging_dir/toolchain-i386_gcc-4.5.0_uClibc-0.9.30.3/lib
--enable-lto --disable-tls
Thread model: posix
gcc version 4.5.0 (GCC)
--
Summary: miscompilation with -Os on x86
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: bernhardloos at googlemail dot com
GCC target triplet: i486-openwrt-linux-uclibc
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44060
[Bug target/44060] miscompilation with -Os on x86
--- Comment #2 from bernhardloos at googlemail dot com 2010-05-10 14:57 --- (In reply to comment #1) > Try -Wstrict-aliasing. > It does produce a warning about dreferencing a type-punned pointer. I tried to compile the snipped with both -fstrict-aliasing and -fno-strict-aliasing and it doesn't produce a difference in the code. Not on the i486 gcc4.5 nor on the gcc4.4 in fedora. Busybox uses this in some places and it did work in the past, so it would be really nice, if this could get fixed. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44060
[Bug target/44060] miscompilation with -Os on x86
--- Comment #5 from bernhardloos at googlemail dot com 2010-05-10 16:48 --- It is a duplicate, my problem happens in exactly the same place. Sorry I missed the other bug. *** This bug has been marked as a duplicate of 43987 *** -- bernhardloos at googlemail dot com changed: What|Removed |Added Status|UNCONFIRMED |RESOLVED Resolution||DUPLICATE http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44060
[Bug middle-end/43987] [4.5 Regression] type-punning causes broken binaries unless -O0 is used
--- Comment #21 from bernhardloos at googlemail dot com 2010-05-10 16:48 --- *** Bug 44060 has been marked as a duplicate of this bug. *** -- bernhardloos at googlemail dot com changed: What|Removed |Added CC||bernhardloos at googlemail ||dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43987
