[PATCH] Improve i386 prologue analyzer

Mark Kettenis
2003-08-17T23:16:01Z

Picking some low-hanging fruit :-). This probably fixes PR
backtrace/1338. I'll be checking this in on the branch if Michael
confirms that this fixes the bug. I'll add a testcase shortly.

Mark

Index: ChangeLog
from Mark Kettenis <kettenis@gnu.org>

* i386-tdep.c (i386_analyze_register_saves): Handle register saves
at the start of a frameless function. This probably fixes PR
backtrace/1338.

Index: i386-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/i386-tdep.c,v
retrieving revision 1.165
diff -u -p -r1.165 i386-tdep.c
--- i386-tdep.c 12 Aug 2003 16:12:33 -0000 1.165
+++ i386-tdep.c 17 Aug 2003 23:11:19 -0000
@@ -571,23 +571,22 @@ static CORE_ADDR
i386_analyze_register_saves (CORE_ADDR pc, CORE_ADDR current_pc,
struct i386_frame_cache *cache)
{
- if (cache->locals >= 0)
- {
- CORE_ADDR offset;
- unsigned char op;
- int i;
+ CORE_ADDR offset = 0;
+ unsigned char op;
+ int i;

- offset = - 4 - cache->locals;
- for (i = 0; i < 8 && pc < current_pc; i++)
- {
- op = read_memory_unsigned_integer (pc, 1);
- if (op < 0x50 || op > 0x57)
- break;
+ if (cache->locals > 0)
+ offset -= cache->locals;
+ for (i = 0; i < 8 && pc < current_pc; i++)
+ {
+ op = read_memory_unsigned_integer (pc, 1);
+ if (op < 0x50 || op > 0x57)
+ break;

- cache->saved_regs[op - 0x50] = offset;
- offset -= 4;
- pc++;
- }
+ offset -= 4;
+ cache->saved_regs[op - 0x50] = offset;
+ cache->sp_offset += 4;
+ pc++;
}

return pc;