diff options
Diffstat (limited to 'gdb')
| -rw-r--r-- | gdb/ChangeLog | 7 | ||||
| -rw-r--r-- | gdb/i386-tdep.c | 56 |
2 files changed, 46 insertions, 17 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index cbe7bdc..26c6c84 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -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. diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c index 19e7ed9..d51e162 100644 --- a/gdb/i386-tdep.c +++ b/gdb/i386-tdep.c @@ -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); } |