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Re: RFA: Recognize bottom of stack on Linux
Daniel Jacobowitz <drow@mvista.com> writes:
> I like this. The way func_frame_chain_valid should really be used is
> by something like:
>
> /* NOTE: tm-i386nw.h and tm-i386v4.h override this. */
> set_gdbarch_frame_chain_valid (gdbarch, file_frame_chain_valid);
>
> (copied from i386-tdep.c).
>
> Does this patch work for you?
Yes, thanks. I've included a revised version of my patch below.
> I'm curious as to why we can't just set this universally, or at least a
> little more globally. Most things that have a main () use it as a
> normal main (). I'd propose that we set it as the default frame chain,
> and provide/document an option to ignore inside_main_func.
Well, gdbarch is never supposed to change the default behavior of
macros; this helps us convert pre-gdbarch targets incrementally.
Simply turning on gdbarch for one's target ideally wouldn't change its
behavior at all.
2002-02-06 Jim Blandy <jimb@redhat.com>
Fix from Daniel Jacobowitz:
* config/i386/tm-linux.h (FRAME_CHAIN_VALID): Use
`func_frame_chain_valid' for this.
* i386-tdep.c (i386_gdbarch_init): Note that tm-linux.h is
overriding the selection we make here.
Index: gdb/i386-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/i386-tdep.c,v
retrieving revision 1.50
diff -c -r1.50 i386-tdep.c
*** gdb/i386-tdep.c 2002/01/01 16:29:43 1.50
--- gdb/i386-tdep.c 2002/02/06 19:19:27
***************
*** 1324,1330 ****
set_gdbarch_pc_in_call_dummy (gdbarch, pc_in_call_dummy_on_stack);
! /* NOTE: tm-i386nw.h and tm-i386v4.h override this. */
set_gdbarch_frame_chain_valid (gdbarch, file_frame_chain_valid);
/* NOTE: tm-i386aix.h, tm-i386bsd.h, tm-i386os9k.h, tm-linux.h,
--- 1324,1330 ----
set_gdbarch_pc_in_call_dummy (gdbarch, pc_in_call_dummy_on_stack);
! /* NOTE: tm-i386nw.h, tm-i386v4.h, and tm-linux.h override this. */
set_gdbarch_frame_chain_valid (gdbarch, file_frame_chain_valid);
/* NOTE: tm-i386aix.h, tm-i386bsd.h, tm-i386os9k.h, tm-linux.h,
Index: gdb/config/i386/tm-linux.h
===================================================================
RCS file: /cvs/src/src/gdb/config/i386/tm-linux.h,v
retrieving revision 1.16
diff -c -r1.16 tm-linux.h
*** gdb/config/i386/tm-linux.h 2001/11/08 00:03:52 1.16
--- gdb/config/i386/tm-linux.h 2002/02/06 19:19:28
***************
*** 82,87 ****
--- 82,98 ----
#define IN_SIGTRAMP(pc, name) i386_linux_in_sigtramp (pc, name)
extern int i386_linux_in_sigtramp (CORE_ADDR, char *);
+ /* On Linux, the entry point is called _start, but that invokes
+ something called __libc_start_main, which calls main. So if we
+ want the stack to end at main (as it does for most GDB targets),
+ it's not enough for us to use inside_entry_func or
+ inside_entry_file; that rule will only trigger after we've included
+ __libc_start_main in the backtrace, which we don't want.
+ func_frame_chain_valid checks both for `main', and for the entry
+ point function. */
+ /* Use the alternate method of determining valid frame chains. */
+ #define FRAME_CHAIN_VALID(fp,fi) func_frame_chain_valid (fp, fi)
+
#undef FRAME_CHAIN
#define FRAME_CHAIN(frame) i386_linux_frame_chain (frame)
extern CORE_ADDR i386_linux_frame_chain (struct frame_info *frame);