$ install/bin/arm-none-linux-gnueabi-gcc --version
arm-none-linux-gnueabi-gcc (GCC) 4.5.0 20091214 (experimental)
[...]
This GCC contains the following patch for gcc/config/arm/arm.c:
@@ -1877,7 +1877,8 @@ arm_override_options (void)
debug info. However this also creates the .eh_frame
section, so disable them until GAS can handle
this properly. See PR40521. */
- if (TARGET_AAPCS_BASED)
+ if (TARGET_AAPCS_BASED
+ && !getenv("GCC_ALLOW_CFI"))
flag_dwarf2_cfi_asm = 0;
GCC created incorrect CFI:
$ cat d.c
void foo(void)
{
register int r7 asm("r7");
asm volatile ("" : : "r" (r7) : "memory");
}
$ GCC_ALLOW_CFI= install/bin/arm-none-linux-gnueabi-gcc -g -O -c -o d.o d.c
$ install/bin/arm-none-linux-gnueabi-objdump -dr d.o
d.o: file format elf32-littlearm
Disassembly of section .text:
00000000 <foo>:
0: e52d7004 push {r7} ; (str r7, [sp, #-4]!)
4: e8bd0080 pop {r7}
8: e12fff1e bx lr
$ install/bin/arm-none-linux-gnueabi-readelf -wf d.o
Contents of the .debug_frame section:
00000000 0000000c ffffffff CIE
Version: 1
Augmentation: ""
Code alignment factor: 2
Data alignment factor: -4
Return address column: 14
DW_CFA_def_cfa: r13 ofs 0
00000010 00000014 00000000 FDE cie=00000000 pc=00000000..0000000c
DW_CFA_advance_loc: 4 to 00000004
DW_CFA_def_cfa_offset: 4
DW_CFA_advance_loc: 8 to 0000000c
DW_CFA_offset: r7 at cfa-4
DW_CFA_nop
DW_CFA_nop
The .cfi_offset r7, -4 belongs at pos. 4, not 0xc.
Also, for correctness, GCC should emit .cfi_adjust_cfa_offset -4 and
.cfi_restore r7 at pos. 8, see PR42403.
--
Summary: Incorrect CFI generated
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: tschwinge at gcc dot gnu dot org
GCC target triplet: arm-none-linux-gnueabi
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42404
