[rfa/symtab] Move find_pc_section call to lookup_minimal_symbol_by_pc

[Andrew Cagney <cagney@gnu.org>]

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Hello,

Ref: RFA symtab: Fix for PR c++/1267 ("next" and shared libraries)
http://sources.redhat.com/ml/gdb-patches/2003-07/msg00354.html

The change unfortunatly broke IRIX 6.5's host compiler which is using 
mdebugread :-(  That code was looking for a symbol in the absolute 
section "*ABS*" but the PR/1267 change was causing *ABS* symbols to be 
ignored (find_pc_section didn't return an absolute section).

Since the underlying problem with PR/1267 was with the frame code 
needing a minimal symbol that was in the same section as the frame's PC, 
and that code [indirectly] calls lookup_minimal_symbol_by_pc, I moved 
the find_pc_section call to that function.

Tested on i386 GNU/Linux (dwarf 2) with no regressions.
Tested on PPC NetBSD (stabs) with no regressions.
Tested on IRIX and all the warnings, and many failures, disappeared.
See gdb/1519 for how to exercise the bug.

ok?
Andrew

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2004-01-27  Andrew Cagney  <cagney@redhat.com>

	* minsyms.c (lookup_minimal_symbol_by_pc): Use find_pc_section
	instead of find_pc_mapped_section.
	(lookup_minimal_symbol_by_pc_section): If the SECTION is NULL, do
	not default to the section containing PC.  Fix PR gdb/1519.

Index: minsyms.c
===================================================================
RCS file: /cvs/src/src/gdb/minsyms.c,v
retrieving revision 1.39
diff -u -r1.39 minsyms.c
--- minsyms.c	11 Nov 2003 20:04:52 -0000	1.39
+++ minsyms.c	27 Jan 2004 21:24:26 -0000
@@ -355,7 +355,7 @@
 
 /* Search through the minimal symbol table for each objfile and find
    the symbol whose address is the largest address that is still less
-   than or equal to PC, and matches SECTION (if non-null).  Returns a
+   than or equal to PC, and matches SECTION (if non-NULL).  Returns a
    pointer to the minimal symbol if such a symbol is found, or NULL if
    PC is not in a suitable range.  Note that we need to look through
    ALL the minimal symbol tables before deciding on the symbol that
@@ -374,20 +374,23 @@
   struct minimal_symbol *best_symbol = NULL;
   struct obj_section *pc_section;
 
-  /* pc has to be in a known section. This ensures that anything beyond
-     the end of the last segment doesn't appear to be part of the last
-     function in the last segment.  */
+  /* PC has to be in a known section.  This ensures that anything
+     beyond the end of the last segment doesn't appear to be part of
+     the last function in the last segment.  */
   pc_section = find_pc_section (pc);
   if (pc_section == NULL)
     return NULL;
 
-  /* If no section was specified, then just make sure that the PC is in
-     the same section as the minimal symbol we find.  */
-  if (section == NULL)
-    section = pc_section->the_bfd_section;
-
-  /* FIXME drow/2003-07-19: Should we also check that PC is in SECTION
-     if we were passed a non-NULL SECTION argument?  */
+  /* NOTE: cagney/2004-01-27: Removed code (added 2003-07-19) that was
+     trying to force the PC into a valid section as returned by
+     find_pc_section.  It broke IRIX 6.5 mdebug which relies on this
+     code returning an absolute symbol - the problem was that
+     find_pc_section wasn't returning an absolute section and hence
+     the code below would skip over absolute symbols.  Since the
+     original problem was with finding a frame's function, and that
+     uses [indirectly] lookup_minimal_symbol_by_pc, the original
+     problem has been fixed by having that function use
+     find_pc_section.  */
 
   for (objfile = object_files;
        objfile != NULL;
@@ -497,7 +500,13 @@
 struct minimal_symbol *
 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
 {
-  return lookup_minimal_symbol_by_pc_section (pc, find_pc_mapped_section (pc));
+  /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
+     force the section but that (well unless you're doing overlay
+     debugging) always returns NULL making the call somewhat useless.  */
+  struct obj_section *section = find_pc_section (pc);
+  if (section == NULL)
+    return NULL;
+  return lookup_minimal_symbol_by_pc_section (pc, section->the_bfd_section);
 }
 \f