darkkirb/old-cross-binutils
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Partial fix for PR backtrace/1718.

Browse source 
* i386-tdep.c (i386_analyze_frame_setup): Handle more instructions
that GCC migrates into the prolugue.  Don't handle any
instructions that clobber %ebx.
This commit is contained in:
Mark Kettenis 2004-07-24 12:59:52 +00:00
parent 822c97322c
commit b463213160
2 changed files with 46 additions and 17 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
gdb/ChangeLog
View file

@ -1,3 +1,10 @@
2004-07-24 Mark Kettenis <kettenis@gnu.org>
Partial fix for PR backtrace/1718.
* i386-tdep.c (i386_analyze_frame_setup): Handle more instructions
that GCC migrates into the prolugue. Don't handle any
instructions that clobber %ebx.
2004-07-23 Andrew Cagney <cagney@gnu.org>
Use regcache_raw_collect instead of regcache_collect.

56
gdb/i386-tdep.c
View file

@ -503,20 +503,28 @@ i386_analyze_frame_setup (CORE_ADDR pc, CORE_ADDR current_pc,
op = read_memory_unsigned_integer (pc + 1, 1);
/* Check for some special instructions that might be migrated
by GCC into the prologue. We check for
/* Check for some special instructions that might be migrated by
GCC into the prologue. At this point in the prologue, code
should only touch the scratch registers %eax, %ecx and %edx,
so we check for
xorl %ebx, %ebx
movl $XXX, %eax
movl $XXX, %ecx
movl $XXX, %edx
These instructions have opcodes 0xb8, 0xb9 and 0xba.
We also check for
xorl %eax, %eax
xorl %ecx, %ecx
xorl %edx, %edx
xorl %eax, %eax
and the equivalent
subl %ebx, %ebx
subl %eax, %eax
subl %ecx, %ecx
subl %edx, %edx
subl %eax, %eax
Because of the symmetry, there are actually two ways to
encode these instructions; with opcode bytes 0x29 and 0x2b
@ -524,20 +532,34 @@ i386_analyze_frame_setup (CORE_ADDR pc, CORE_ADDR current_pc,
Make sure we only skip these instructions if we later see the
`movl %esp, %ebp' that actually sets up the frame. */
while (op == 0x29 || op == 0x2b || op == 0x31 || op == 0x33)
while ((op >= 0xb8 && op <= 0xba)
|| op == 0x29 || op == 0x2b
|| op == 0x31 || op == 0x33)
{
op = read_memory_unsigned_integer (pc + skip + 2, 1);
switch (op)
if (op >= 0xb8 && op <= 0xba)
{
case 0xdb: /* %ebx */
case 0xc9: /* %ecx */
case 0xd2: /* %edx */
case 0xc0: /* %eax */
skip += 2;
break;
default:
return pc + 1;
/* Skip the `movl' instructions cited above. */
skip += 5;
}
else
{
/* Skip the `subl' and `xorl' instructions cited above. */
op = read_memory_unsigned_integer (pc + skip + 2, 1);
switch (op)
{
case 0xc0: /* %eax */
case 0xc9: /* %ecx */
case 0xd2: /* %edx */
skip += 2;
break;
default:
return pc + 1;
}
}
/* If that's all, return now. */
if (current_pc <= pc + skip + 1)
return current_pc;
op = read_memory_unsigned_integer (pc + skip + 1, 1);
}