Attachment 160041 Details for Bug 249490 – Candidate fix

[patch] Candidate fix

diffs (text/plain), 3.96 KB, created by Andrew Cagney on 2007-07-26 17:02:09 UTC

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Creator: Andrew Cagney

Created: 2007-07-26 17:02:09 UTC

Size: 3.96 KB

patch

obsolete

>Index: frysk-imports/elfutils/libdwfl/ChangeLog
>2007-07-26  Andrew Cagney  <cagney@redhat.com>
>
>	* dwfl_module_addrsym.c (dwfl_module_addrsym): Handle nested
>	symbols (prefer closer and smaller); handle regions between
>	symbols (they have no symbol); handle nested zero-sized symbols
>	(discard them).
>
>Index: frysk-imports/elfutils/libdwfl/dwfl_module_addrsym.c
>===================================================================
>RCS file: /cvs/frysk/frysk-imports/elfutils/libdwfl/dwfl_module_addrsym.c,v
>retrieving revision 1.2
>diff -p -u -r1.2 dwfl_module_addrsym.c
>--- frysk-imports/elfutils/libdwfl/dwfl_module_addrsym.c	26 Apr 2007 15:18:43 -0000	1.2
>+++ frysk-imports/elfutils/libdwfl/dwfl_module_addrsym.c	26 Jul 2007 16:47:38 -0000
>@@ -51,7 +51,7 @@
> 
> const char *
> dwfl_module_addrsym (Dwfl_Module *mod, GElf_Addr addr,
>-					  GElf_Sym *closest_sym, GElf_Word *shndxp)
>+		     GElf_Sym *closest_sym, GElf_Word *shndxp)
> {
>   int syments = INTUSE(dwfl_module_getsymtab) (mod);
>   if (syments < 0)
>@@ -99,7 +99,7 @@ dwfl_module_addrsym (Dwfl_Module *mod, G
> 
>   /* Look through the symbol table for a matching symbol.  */
>   const char *closest_name = NULL;
>-  closest_sym->st_value = 0;
>+  memset(closest_sym, 0, sizeof(*closest_sym));
>   GElf_Word closest_shndx = SHN_UNDEF;
>   for (int i = 1; i < syments; ++i)
>     {
>@@ -108,28 +108,75 @@ dwfl_module_addrsym (Dwfl_Module *mod, G
>       const char *name = INTUSE(dwfl_module_getsym) (mod, i, &sym, &shndx);
>       if (name != NULL && sym.st_value <= addr)
> 	{
>-		inline void closest (void)
>-		{
>+	  inline void closest (void)
>+	    {
>+	      printf("closest\n");
> 	      *closest_sym = sym;
> 	      closest_shndx = shndx;
> 	      closest_name = name;
>-		}
>+	    }
>+	  
>+	  printf("%lx: %s %lx %d\n", (long)addr, name, (long)sym.st_value, (int)sym.st_size);
> 
>+	  /* This symbol contains ADDR; but is it better than the
>+	     previous candidate?  */
> 	  if (addr < sym.st_value + sym.st_size)
>+	    {
>+	      printf("contains addr\n");
>+	      if (addr >= closest_sym->st_value + closest_sym->st_size)
> 		{
>-	      closest ();
>-	      break;
>+		  /* Ha! The previous candidate doesn't even contain
>+		     ADDR; replace it.  */
>+		  closest();
>+		  continue;
> 		}
>-
>-	  /* Handwritten assembly symbols sometimes have no st_size.
>-	     If no symbol with proper size includes the address, we'll
>-	     use the closest one that is in the same section as ADDR.   */
>-	  if (sym.st_size == 0 && sym.st_value >= closest_sym->st_value
>+	      if (sym.st_value > closest_sym->st_value)
>+		{
>+		  /* This candidate is closer to ADDR.  */
>+		  closest ();
>+		  continue;
>+		}
>+	      if (sym.st_value == closest_sym->st_value
>+		  && sym.st_size < closest_sym->st_size)
>+		{
>+		  /* This candidate, while having an identical value,
>+		     is at least smaller.  */
>+		  closest ();
>+		  continue;
>+		}
>+	      /* Discard this candidate, no better than the previous
>+		 sized symbol that contained ADDR.  */
>+	      continue;
>+	    }
>+	  
>+	  /* The current closest symbol contains ADDR, can't do better
>+	     than that.  */
>+	  if (addr < closest_sym->st_value + closest_sym->st_size)
>+	    continue;
>+
>+	  /* Save the symbol with the closer address.  If the closest
>+	     symbol has no size (typically from hand written
>+	     assembler) then it is the best candidate.  If the symbol
>+	     has size but doesn't contain ADDR then it is still saved
>+	     (but discarded below); this prevents a more distant
>+	     unsized symbol being selected. */
>+	  if (sym.st_value >= closest_sym->st_value
> 	      && same_section (&sym, shndx))
>-	    closest ();
>+	    {
>+	      closest ();
>+	      continue;
>+	    }
> 	}
>     }
> 
>+  /* If the closest symbol has a size doesn't contain ADDR, discard
>+     it.  There must be a hole in the symbol table.  */
>+  if (closest_sym->st_size > 0 && addr >= closest_sym->st_value + closest_sym->st_size)
>+    {
>+      memset(closest_sym, 0, sizeof(*closest_sym));
>+      return NULL;
>+    }
>+
>   if (shndxp != NULL)
>     *shndxp = closest_shndx;
>   return closest_name;

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Attachments on bug 249490: 160041