[patch] gdb crash in cp_scan_for_anonymous_namespace

[Aleksandar Ristovski <aristovski at qnx dot com>]

Hello,

I have encountered a gdb crash (gdb 7.3.1 based qnx gdb) in function 
cp_scan_for_anonymous_namespace.

What happens is that we get into 'define_symbol' function having an 
objfile without any symtabs. cp_scan_for_anonymous_namespaces 
dereferences symbol->symtab and crashes gdb.

This is all observed/debugged on gdb7.3.1 code base, but from looking at 
HEAD code, the possibility still exists.


I haven't created a testcase yet (the case I have is quite complicated 
with numerous shared objects involved and a core).


There are no regressions in existing test suite, tested on 
"x86_64-unknown-linux-gnu".


Thanks,

Aleksandar Ristovski




ChangeLog:


2011-10-20  Aleksandar Ristovski  <aristovski@qnx.com>

        * cp-namespace.c (cp_scan_for_anonymous_namespaces): Changed 
function
        arguments by adding OBJFILE.  Instead of getting objfile from
        symbol's symtab, use new argument OBJFILE.
        * cp-support.h (cp_scan_for_anonymous_namespaces): Changed function
        arguments by adding OBJFILE.
        * gdb/dwarf2read.c (new_symbol_full): Change call to
        cp_scan_for_anonymous_namespaces to match new signature.
        * gdb/stabsread.c (define_symbol): Change call to
        cp_scan_for_anonymous_namespaces to match new signature.
Index: gdb/cp-namespace.c
===================================================================
RCS file: /cvs/src/src/gdb/cp-namespace.c,v
retrieving revision 1.54
diff -u -p -r1.54 cp-namespace.c
--- gdb/cp-namespace.c	29 Jun 2011 22:05:15 -0000	1.54
+++ gdb/cp-namespace.c	20 Oct 2011 18:26:22 -0000
@@ -53,7 +53,8 @@ static struct type *cp_lookup_transparen
    anonymous namespace; if so, add an appropriate using directive.  */
 
 void
-cp_scan_for_anonymous_namespaces (const struct symbol *symbol)
+cp_scan_for_anonymous_namespaces (const struct symbol *const symbol,
+				  struct objfile *const objfile)
 {
   if (SYMBOL_DEMANGLED_NAME (symbol) != NULL)
     {
@@ -96,7 +97,7 @@ cp_scan_for_anonymous_namespaces (const 
 		 namespace given by the previous component if there is
 		 one, or to the global namespace if there isn't.  */
 	      cp_add_using_directive (dest, src, NULL, NULL, NULL,
-	                              &SYMBOL_SYMTAB (symbol)->objfile->objfile_obstack);
+	                              &objfile->objfile_obstack);
 	    }
 	  /* The "+ 2" is for the "::".  */
 	  previous_component = next_component + 2;
Index: gdb/cp-support.h
===================================================================
RCS file: /cvs/src/src/gdb/cp-support.h,v
retrieving revision 1.45
diff -u -p -r1.45 cp-support.h
--- gdb/cp-support.h	18 Aug 2011 16:17:38 -0000	1.45
+++ gdb/cp-support.h	20 Oct 2011 18:26:22 -0000
@@ -197,7 +197,8 @@ extern void cp_set_block_scope (const st
 				const char *processing_current_prefix,
 				int processing_has_namespace_info);
 
-extern void cp_scan_for_anonymous_namespaces (const struct symbol *symbol);
+extern void cp_scan_for_anonymous_namespaces (const struct symbol *symbol,
+					      struct objfile *objfile);
 
 extern struct symbol *cp_lookup_symbol_nonlocal (const char *name,
 						 const struct block *block,
Index: gdb/dwarf2read.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2read.c,v
retrieving revision 1.574
diff -u -p -r1.574 dwarf2read.c
--- gdb/dwarf2read.c	17 Oct 2011 12:57:14 -0000	1.574
+++ gdb/dwarf2read.c	20 Oct 2011 18:26:23 -0000
@@ -11936,7 +11936,7 @@ new_symbol_full (struct die_info *die, s
 	 namespaces based on the demangled name.  */
       if (!processing_has_namespace_info
 	  && cu->language == language_cplus)
-	cp_scan_for_anonymous_namespaces (sym);
+	cp_scan_for_anonymous_namespaces (sym, objfile);
     }
   return (sym);
 }
Index: gdb/stabsread.c
===================================================================
RCS file: /cvs/src/src/gdb/stabsread.c,v
retrieving revision 1.138
diff -u -p -r1.138 stabsread.c
--- gdb/stabsread.c	18 May 2011 16:30:36 -0000	1.138
+++ gdb/stabsread.c	20 Oct 2011 18:26:23 -0000
@@ -729,7 +729,7 @@ define_symbol (CORE_ADDR valu, char *str
 	SYMBOL_SET_NAMES (sym, string, p - string, 1, objfile);
 
       if (SYMBOL_LANGUAGE (sym) == language_cplus)
-	cp_scan_for_anonymous_namespaces (sym);
+	cp_scan_for_anonymous_namespaces (sym, objfile);
 
     }
   p++;