In gcc/unwind-dw2-fde.h
/* The first few fields of a CIE. The CIE_id field is 0 for a CIE,
to distinguish it from a valid FDE. FDEs are aligned to an addressing
unit boundary, but the fields within are unaligned. */
struct dwarf_cie
{
uword length;
sword CIE_id;
ubyte version;
unsigned char augmentation[];
} __attribute__ ((packed, aligned (__alignof__ (void *))));
/* The first few fields of an FDE. */
struct dwarf_fde
{
uword length;
sword CIE_delta;
unsigned char pc_begin[];
} __attribute__ ((packed, aligned (__alignof__ (void *))));
It indicates that CIE/FDE should be aligned at the pointer size. But crtstuff.c
has:
STATIC EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[]
__attribute__((section(EH_FRAME_SECTION_NAME), aligned(4)))
= { };
STATIC EH_FRAME_SECTION_CONST int32 __FRAME_END__[]
__attribute__ ((unused, section(EH_FRAME_SECTION_NAME),
aligned(sizeof(int32))))
= { 0 };
This leads to the corrupted .eh_frame section on x86-64:
http://sources.redhat.com/bugzilla/show_bug.cgi?id=2655
--
Summary: The .eh_frame section in crtend.o has wrong aligment
Product: gcc
Version: 4.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: other
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: hjl at lucon dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27576
