[PATCH] Remove zero PC check from blockframe.c:inside_main_func()

Mark Kettenis
2003-12-13T15:09:34Z

It really makes no sense to check for a zero PC here. This function
is only colled from frame.c:get_prev_frame(), and there we already
deal with PC being zero.

The whole concept of using a zero PC as a marker for the end of the
frame chain is somewhat flawed. It prevents us from providing a
meaningful backtrace when the program has called a null function
pointer; see backtrace/1476. At the very least we will have to treat
a zero PC in the innermost differently. Classifying the a zero PC as
being inside the "main" function doesn't help. Therefore this patch
removes the first obstackle in fixing that PR.

Objections. Otherwise I'll commit this within a few days.

Mark

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

* blockframe.c (inside_main_func): Don't treat a zero PC specially.
Needed to fix PR backtrace/1476.

Index: blockframe.c
===================================================================
RCS file: /cvs/src/src/gdb/blockframe.c,v
retrieving revision 1.83
diff -u -p -r1.83 blockframe.c
--- blockframe.c 13 Dec 2003 13:16:52 -0000 1.83
+++ blockframe.c 13 Dec 2003 14:50:01 -0000
@@ -73,17 +73,12 @@ deprecated_inside_entry_file (CORE_ADDR
}

/* Test whether PC is in the range of addresses that corresponds to
- the "main" function.
-
- A PC of zero is always considered to be the bottom of the stack. */
+ the "main" function. */

int
inside_main_func (CORE_ADDR pc)
{
struct minimal_symbol *msymbol;
-
- if (pc == 0)
- return 1;

if (symfile_objfile == 0)
return 0;