PR24402, global buffer overflow in symtab_finalize

	PR 24402
	* symtab.c (symtab_finalize): Init prev_addr to one less than
	first symbol address, not one more.  Correct test for symbols
	with leading underscores.

Author: amodra

gprof/ChangeLog

@@ -1,3 +1,10 @@
+2019-04-01  Alan Modra  <amodra@gmail.com>
+
+	PR 24402
+	* symtab.c (symtab_finalize): Init prev_addr to one less than
+	first symbol address, not one more.  Correct test for symbols
+	with leading underscores.
+
 2019-01-21  Nick Clifton  <nickc@redhat.com>
 
 	* po/tr.po: Updated Turkish translation.

gprof/symtab.c

@@ -89,7 +89,7 @@ symtab_finalize (Sym_Table *tab)
 
   /* Remove duplicate entries to speed-up later processing and
      set end_addr if its not set yet.  */
-  prev_addr = tab->base[0].addr + 1;
+  prev_addr = tab->base[0].addr - 1;
 
   for (src = dst = tab->base; src < tab->limit; ++src)
     {
@@ -107,7 +107,7 @@ symtab_finalize (Sym_Table *tab)
 		  && ((src->is_func && !dst[-1].is_func)
 		      || ((src->is_func == dst[-1].is_func)
 			  && ((src->name[0] != '_' && dst[-1].name[0] == '_')
-			      || (src->name[0]
+			      || (src->name[0] == '_' && dst[-1].name[0] == '_'
 				  && src->name[1] != '_'
 				  && dst[-1].name[1] == '_'))))))
 	    {