[patch] Removal of the FIND_PC_SECT_PSYMTAB search [Re: [patch] Discontiguous PSYMTABs]

Jan Kratochvil jan.kratochvil@redhat.com
Mon Dec 10 00:21:00 GMT 2007


On Sun, 09 Dec 2007 21:31:38 +0100, Jan Kratochvil wrote:
...
> Attaching the fix for discontiguous psymtabs based on the addrmap framework.
...
> #2 My folowup mail will offer a future removal of FIND_PC_SECT_PSYMTAB_IS_VALID.

This is the promised simplification.  It has no testsuite regressions on x86_64
GNU/Linux but I feel such test is not sufficient.

I guess the heuristic complicated search there was just to deal with
overlapping PSYMTABs - these are now solved the clean way by ADDRMAP.

But some compilers may not produce the right CU DW_AT_ranges and/or the debug
info formats may not support it, I do not know.


Regards,
Jan
-------------- next part --------------
2007-12-09  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* symtab.c (find_pc_sect_psymtab_is_valid): Remoev the function.
	(find_pc_sect_psymtab): Remove the FIND_PC_SECT_PSYMTAB_IS_VALID call,
	assume the found PSYMTAB is always valid.

diff -u -rup gdb-addrmap-conservative/symtab.c gdb/symtab.c
--- ./gdb-addrmap-conservative/symtab.c	2007-12-09 17:59:30.000000000 +0100
+++ ./gdb/symtab.c	2007-12-09 20:42:33.000000000 +0100
@@ -760,83 +760,6 @@ matching_bfd_sections (asection *first, 
   return 0;
 }
 
-/* Find which partial symtab contains PC and SECTION starting at psymtab PST.
-   We may find a different psymtab than PST.  See FIND_PC_SECT_PSYMTAB.  */
-
-struct partial_symtab *
-find_pc_sect_psymtab_is_valid (CORE_ADDR pc, asection *section,
-			       struct partial_symtab *pst,
-			       struct minimal_symbol *msymbol)
-{
-  struct objfile *objfile = pst->objfile;
-  struct partial_symtab *tpst;
-  struct partial_symtab *best_pst = pst;
-  CORE_ADDR best_addr = pst->textlow;
-
-  /* An objfile that has its functions reordered might have
-     many partial symbol tables containing the PC, but
-     we want the partial symbol table that contains the
-     function containing the PC.  */
-  if (!(objfile->flags & OBJF_REORDERED) &&
-      section == 0)	/* can't validate section this way */
-    return pst;
-
-  if (msymbol == NULL)
-    return (pst);
-
-  /* The code range of partial symtabs sometimes overlap, so, in
-     the loop below, we need to check all partial symtabs and
-     find the one that fits better for the given PC address. We
-     select the partial symtab that contains a symbol whose
-     address is closest to the PC address.  By closest we mean
-     that find_pc_sect_symbol returns the symbol with address
-     that is closest and still less than the given PC.  */
-  for (tpst = pst; tpst != NULL; tpst = tpst->next)
-    {
-      if (pc >= tpst->textlow && pc < tpst->texthigh)
-	{
-	  struct partial_symbol *p;
-	  CORE_ADDR this_addr;
-
-	  /* NOTE: This assumes that every psymbol has a
-	     corresponding msymbol, which is not necessarily
-	     true; the debug info might be much richer than the
-	     object's symbol table.  */
-	  p = find_pc_sect_psymbol (tpst, pc, section);
-	  if (p != NULL
-	      && SYMBOL_VALUE_ADDRESS (p)
-	      == SYMBOL_VALUE_ADDRESS (msymbol))
-	    return tpst;
-
-	  /* Also accept the textlow value of a psymtab as a
-	     "symbol", to provide some support for partial
-	     symbol tables with line information but no debug
-	     symbols (e.g. those produced by an assembler).  */
-	  if (p != NULL)
-	    this_addr = SYMBOL_VALUE_ADDRESS (p);
-	  else
-	    this_addr = tpst->textlow;
-
-	  /* Check whether it is closer than our current
-	     BEST_ADDR.  Since this symbol address is
-	     necessarily lower or equal to PC, the symbol closer
-	     to PC is the symbol which address is the highest.
-	     This way we return the psymtab which contains such
-	     best match symbol. This can help in cases where the
-	     symbol information/debuginfo is not complete, like
-	     for instance on IRIX6 with gcc, where no debug info
-	     is emitted for statics. (See also the nodebug.exp
-	     testcase.) */
-	  if (this_addr > best_addr)
-	    {
-	      best_addr = this_addr;
-	      best_pst = tpst;
-	    }
-	}
-    }
-  return best_pst;
-}
-
 /* Find which partial symtab contains PC and SECTION.  Return 0 if
    none.  We return the psymtab that contains a symbol whose address
    exactly matches PC, or, if we cannot find an exact match, the
@@ -867,14 +790,7 @@ find_pc_sect_psymtab (CORE_ADDR pc, asec
 
 	  pst = addrmap_find (objfile->psymtabs_addrmap, pc);
 	  if (pst != NULL)
-	    {
-	      struct partial_symtab *best_pst;
-
-	      best_pst = find_pc_sect_psymtab_is_valid (pc, section, pst,
-							msymbol);
-	      if (best_pst != NULL)
-		return best_pst;
-	    }
+	    return pst;
 	  /* Existing PSYMTABS_ADDRMAP should cover all the PSYMTABS of
 	     OBJFILE, there is no need to scan the remaining ones by hand.  */
 	}
@@ -884,14 +800,7 @@ find_pc_sect_psymtab (CORE_ADDR pc, asec
 
 	  ALL_OBJFILE_PSYMTABS (objfile, pst)
 	    if (pc >= pst->textlow && pc < pst->texthigh)
-	      {
-		struct partial_symtab *best_pst;
-
-	        best_pst = find_pc_sect_psymtab_is_valid (pc, section, pst,
-							  msymbol);
-		if (best_pst != NULL)
-		  return best_pst;
-	      }
+	      return pst;
 	}
     }
 


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