diff options
Diffstat (limited to 'gdb/i386-tdep.c')
| -rw-r--r-- | gdb/i386-tdep.c | 40 |
1 files changed, 22 insertions, 18 deletions
diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c index 9859a7f..b59e342 100644 --- a/gdb/i386-tdep.c +++ b/gdb/i386-tdep.c @@ -702,7 +702,6 @@ struct i386_frame_cache CORE_ADDR saved_regs[I386_NUM_SAVED_REGISTERS]; CORE_ADDR saved_sp; CORE_ADDR return_pc; - int frameless; }; /* Parse the first few instructions the function to see what registers @@ -743,7 +742,6 @@ i386_frame_cache (struct frame_info *frame, void **cachep) memset (cache->saved_regs, 0, sizeof (cache->saved_regs)); cache->saved_sp = 0; cache->return_pc = 0; - cache->frameless = 0; /* If this is a signal trampoline, get %esp and %eip from the signal context. */ @@ -796,7 +794,6 @@ i386_frame_cache (struct frame_info *frame, void **cachep) setup yet. In the latter case only %eip and %esp have changed, and we can determine their previous values. We pretend we can do the same in the former case. */ - cache->frameless = 1; frame_read_register (frame, SP_REGNUM, buf); cache->saved_regs[PC_REGNUM] = extract_address (buf, 4); @@ -836,21 +833,28 @@ i386_frame_id_unwind (struct frame_info *frame, void **cachep, /* Start with a NULL frame ID. */ *id = null_frame_id; - /* The frame's base is the address of a 4-byte word containing the - calling frame's address. - - Signal trampolines don't have a meaningful frame. The frame - pointer value we use is actually the frame pointer of the calling - frame -- that is, the frame which was in progress when the signal - trampoline was entered. GDB mostly treats this frame pointer - value as a magic cookie. We detect the case of a signal - trampoline by testing for get_frame_type() == SIGTRAMP_FRAME, - which is set based on PC_IN_SIGTRAMP. */ - - if (get_frame_type (frame) == SIGTRAMP_FRAME || cache->frameless) - id->base = get_frame_base (frame); - else if (!inside_entry_file (get_frame_pc (frame))) - id->base = read_memory_unsigned_integer (get_frame_base (frame), 4); + /* In principle, %ebp holds the frame pointer, which holds the base + address for the current stack frame. However, for functions that + don't need it, the frame pointer is optional. For these + "frameless" functions the frame pointer is actaully the frame + pointer of the calling frame. Signal trampolines are just a + special case of a "frameless" function. They (usually) share + their frame pointer with the frame that was in progress when the + signal occurred. + + FIXME: kettenis/20030316: If we're at the start of a function, + and this function's frame hasn't been setup yet, we essentially + treat the function as frameless. As a result, once the prologue + of the function has been executed and the frame has been set up, + the frame's base changes, which isn't good. */ + + if (!inside_entry_file (get_frame_pc (frame))) + { + char buf[4]; + + frame_unwind_register (frame, FP_REGNUM, buf); + id->base = extract_address (buf, 4); + } id->pc = cache->return_pc; } |