Re: [RFA] Handle stack underflow in dbxread.c

[Klee Dienes <klee@apple.com>]

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On Monday, November 18, 2002, at 12:40 PM, Jim Blandy wrote:

>
> Okay, that looks like a good change to me --- please commit it.
>
> But rather than making pop_context a hairy macro, could you make it a
> function in buildsym.c, right after push_context?


Gladly.  Committed the following:


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2002-11-18  Klee Dienes  <kdienes@apple.com>

        * buildsym.h (pop_context): Convert to function, defined in
        buildsym.c.
        * buildsym.c: Include gdb_assert.h.
        (pop_context): Implement as C function.  Add check for stack
        underflow.
        * dbxread.c (process_one_symbol): Complain and stop processing
        that symbol if we are already at the top of the context stack for
        a function-end N_FUN (this would imply an umatched RBRAC).  Ditto
        when processing N_RBRAC.

Index: buildsym.c
===================================================================
RCS file: /cvs/src/src/gdb/buildsym.c,v
retrieving revision 1.21
diff -u -r1.21 buildsym.c
--- buildsym.c	25 Oct 2002 22:25:55 -0000	1.21
+++ buildsym.c	18 Nov 2002 19:13:17 -0000
@@ -33,6 +33,7 @@
 #include "symfile.h"
 #include "objfiles.h"
 #include "gdbtypes.h"
+#include "gdb_assert.h"
 #include "complaints.h"
 #include "gdb_string.h"
 #include "expression.h"		/* For "enum exp_opcode" used by... */
@@ -1100,6 +1101,14 @@
 
   return new;
 }
+
+struct context_stack *
+pop_context (void)
+{
+  gdb_assert (context_stack_depth > 0);
+  return (&context_stack[--context_stack_depth]);
+}
+
 \f
 
 /* Compute a small integer hash code for the given name. */
Index: buildsym.h
===================================================================
RCS file: /cvs/src/src/gdb/buildsym.h,v
retrieving revision 1.6
diff -u -r1.6 buildsym.h
--- buildsym.h	8 Nov 2002 20:05:10 -0000	1.6
+++ buildsym.h	18 Nov 2002 19:13:17 -0000
@@ -173,12 +173,6 @@
 
 EXTERN int context_stack_size;
 
-/* Macro "function" for popping contexts from the stack.  Pushing is
-   done by a real function, push_context.  This returns a pointer to a
-   struct context_stack.  */
-
-#define	pop_context() (&context_stack[--context_stack_depth]);
-
 /* Non-zero if the context stack is empty.  */
 #define outermost_context_p() (context_stack_depth == 0)
 
@@ -271,6 +265,8 @@
 extern void buildsym_init (void);
 
 extern struct context_stack *push_context (int desc, CORE_ADDR valu);
+
+extern struct context_stack *pop_context (void);
 
 extern void record_line (struct subfile *subfile, int line, CORE_ADDR pc);
 
Index: dbxread.c
===================================================================
RCS file: /cvs/src/src/gdb/dbxread.c,v
retrieving revision 1.36
diff -u -r1.36 dbxread.c
--- dbxread.c	25 Oct 2002 22:25:55 -0000	1.36
+++ dbxread.c	18 Nov 2002 19:13:18 -0000
@@ -2774,6 +2774,13 @@
 	{
 	  /* This N_FUN marks the end of a function.  This closes off the
 	     current block.  */
+
+ 	  if (context_stack_depth <= 0)
+ 	    {
+ 	      complain (&lbrac_mismatch_complaint, symnum);
+ 	      break;
+ 	    }
+
 	  record_line (current_subfile, 0, function_start_offset + valu);
 	  within_function = 0;
 	  new = pop_context ();
@@ -2842,6 +2849,12 @@
 	/* On most machines, the block addresses are relative to the
 	   N_SO, the linker did not relocate them (sigh).  */
 	valu += last_source_start_addr;
+
+      if (context_stack_depth <= 0)
+	{
+	  complain (&lbrac_mismatch_complaint, symnum);
+	  break;
+	}
 
       new = pop_context ();
       if (desc != new->depth)