Re: RFA: Patch for SIGSEGV in evaluate_subexp_standard

[Fred Fish <fnf@gofish.ninemoons.com>]

> Approved, if you address Daniel's suggestion somehow.

OK, I've tweaked the call site to handle a NULL return, which is a
normal result and tested for by other callers.  There was already a
test present, it was just not in the right place and needed to be
moved up a couple lines.  Here is the updated patch and ChangeLog
entry.

-Fred

2001-12-10  Fred Fish  <fnf@redhat.com>
 
	* values.c (value_fn_field): Add physname variable.  Use a minimal
	symbol if we don't find a full symbol.  Remove setting of the new
	value's type since that was already done by allocate_value().
	Remove obsolete commented out error call since callees need to
	handle a NULL return, which is possible result not an error.
	* eval.c (evaluate_subexp_standard): Move check for inlined
	functions to precede attempt to dereference a NULL argvec[0].

Index: values.c
===================================================================
RCS file: /cvs/src/src/gdb/values.c,v
retrieving revision 1.29
diff -u -p -r1.29 values.c
--- values.c	2001/11/30 17:47:51	1.29
+++ values.c	2001/12/10 22:50:01
@@ -954,28 +954,40 @@ value_field (register value_ptr arg1, re
 
 /* Return a non-virtual function as a value.
    F is the list of member functions which contains the desired method.
-   J is an index into F which provides the desired method. */
+   J is an index into F which provides the desired method.
 
+   We only use the symbol for its address, so be happy with either a
+   full symbol or a minimal symbol.
+ */
+
 value_ptr
 value_fn_field (value_ptr *arg1p, struct fn_field *f, int j, struct type *type,
 		int offset)
 {
   register value_ptr v;
   register struct type *ftype = TYPE_FN_FIELD_TYPE (f, j);
+  char *physname = TYPE_FN_FIELD_PHYSNAME (f, j);
   struct symbol *sym;
+  struct minimal_symbol *msym;
 
-  sym = lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, j),
-		       0, VAR_NAMESPACE, 0, NULL);
+  sym = lookup_symbol (physname, 0, VAR_NAMESPACE, 0, NULL);
   if (!sym)
+    {
+      msym = lookup_minimal_symbol (physname, NULL, NULL);
+    }
+
+  if (!sym && !msym)
     return NULL;
-/*
-   error ("Internal error: could not find physical method named %s",
-   TYPE_FN_FIELD_PHYSNAME (f, j));
- */
 
   v = allocate_value (ftype);
-  VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym));
-  VALUE_TYPE (v) = ftype;
+  if (sym)
+    {
+      VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym));
+    }
+  else
+    {
+      VALUE_ADDRESS (v) = SYMBOL_VALUE_ADDRESS (msym);
+    }
 
   if (arg1p)
     {

Index: eval.c
===================================================================
RCS file: /cvs/src/src/gdb/eval.c,v
retrieving revision 1.16
diff -u -p -r1.16 eval.c
--- eval.c	2001/11/12 21:20:18	1.16
+++ eval.c	2001/12/10 22:49:57
@@ -917,6 +917,8 @@ evaluate_subexp_standard (struct type *e
 
       if (noside == EVAL_SKIP)
 	goto nosideret;
+      if (argvec[0] == NULL)
+	error ("Cannot evaluate function -- may be inlined");
       if (noside == EVAL_AVOID_SIDE_EFFECTS)
 	{
 	  /* If the return type doesn't look like a function type, call an
@@ -934,8 +936,6 @@ evaluate_subexp_standard (struct type *e
 	  else
 	    error ("Expression of type other than \"Function returning ...\" used as function");
 	}
-      if (argvec[0] == NULL)
-	error ("Cannot evaluate function -- may be inlined");
       return call_function_by_hand (argvec[0], nargs, argvec + 1);
       /* pai: FIXME save value from call_function_by_hand, then adjust pc by adjust_fn_pc if +ve  */