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[Bug libstdc++/64798] [5 regression] g++.old-deja/g++.eh/badalloc1.C FAILs
- From: "rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 26 Jan 2015 15:02:27 +0000
- Subject: [Bug libstdc++/64798] [5 regression] g++.old-deja/g++.eh/badalloc1.C FAILs
- Auto-submitted: auto-generated
- References: <bug-64798-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64798
--- Comment #2 from rguenther at suse dot de <rguenther at suse dot de> ---
On Mon, 26 Jan 2015, Richard Biener wrote:
> On Mon, 26 Jan 2015, ro at gcc dot gnu.org wrote:
>
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64798
> >
> > Bug ID: 64798
> > Summary: [5 regression] g++.old-deja/g++.eh/badalloc1.C FAILs
> > Product: gcc
> > Version: 5.0
> > Status: UNCONFIRMED
> > Severity: normal
> > Priority: P3
> > Component: libstdc++
> > Assignee: unassigned at gcc dot gnu.org
> > Reporter: ro at gcc dot gnu.org
> > CC: rguenth at gcc dot gnu.org
> > Host: sparc*-sun-solaris2.*
> > Target: sparc*-sun-solaris2.*
> > Build: sparc*-sun-solaris2.*
> >
> > Between 20150116 (r219745) and 20150123 (r220039),
> > g++.old-deja/g++.eh/badalloc1.C
> > started to FAIL on 32-bit Solaris/SPARC:
> >
> > FAIL: g++.old-deja/g++.eh/badalloc1.C -std=c++11 execution test
> > FAIL: g++.old-deja/g++.eh/badalloc1.C -std=c++14 execution test
> > FAIL: g++.old-deja/g++.eh/badalloc1.C -std=c++98 execution test
> >
> > Program received signal SIGSEGV, Segmentation fault.
> > [Switching to Thread 1 (LWP 1)]
> > __cxxabiv1::__cxa_throw (obj=0x2195c <arena+92>,
> > tinfo=0x73908 <typeinfo for int>, dest=0x0)
> > at /vol/gcc/src/hg/trunk/local/libstdc++-v3/libsupc++/eh_throw.cc:76
> > 76
> > __GXX_INIT_PRIMARY_EXCEPTION_CLASS(header->exc.unwindHeader.exception_class);
> > 1: x/i $pc
> > => 0xff220314 <__cxxabiv1::__cxa_throw(void*, std::type_info*, void
> > (*)(void*))+96>: sttw %g2, [ %i0 + -24 ]
> > (gdb) where
> > #0 __cxxabiv1::__cxa_throw (obj=0x2195c <arena+92>,
> > tinfo=0x73908 <typeinfo for int>, dest=0x0)
> > at /vol/gcc/src/hg/trunk/local/libstdc++-v3/libsupc++/eh_throw.cc:76
> > #1 0x00011114 in fn_throw ()
> > at
> > /vol/gcc/src/hg/trunk/local/gcc/testsuite/g++.old-deja/g++.eh/badalloc1.C:98
> > #2 0x000112f8 in main ()
> > at
> > /vol/gcc/src/hg/trunk/local/gcc/testsuite/g++.old-deja/g++.eh/badalloc1.C:129
> > (gdb) p $i0-24
> > $3 = 137540
> >
> > The SEGV happens because the sttw target needs to be 8-byte aligned, but is
> > not.
>
> Does malloc return 8-byte aligned memory? Is __alignof__
>
> struct free_entry {
> std::size_t size;
> free_entry *next;
> };
>
> less than 8?
Ah - the issue might be that g++.old-deja/g++.eh/badalloc1.C does
extern "C" void *malloc (size_t size)
{
object *p = reinterpret_cast<object *>(&arena[pos]);
if (fail)
return 0;
p->size = size;
size = (size + __alignof__(object) - 1) & - __alignof__(object);
pos += size + sizeof(object);
thus it aligns to 'object' but 'object' is
struct object
{
size_t size __attribute__((aligned));
};
Richard