gdb/

	* findvar.c (read_var_value): Never return NULL, throw an error
	instead.  Update the function comment.  State symbol name in the error
	messages.
	* python/py-frame.c (frapy_read_var): Remove handling of NULL from
	read_var_value.
	* stack.c (print_frame_args): Likewise.
	* valops.c (value_of_variable): Likewise.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index e7f3da7..9f4697a 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,15 @@
 2011-09-08  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
+       * findvar.c (read_var_value): Never return NULL, throw an error
+       instead.  Update the function comment.  State symbol name in the error
+       messages.
+       * python/py-frame.c (frapy_read_var): Remove handling of NULL from
+       read_var_value.
+       * stack.c (print_frame_args): Likewise.
+       * valops.c (value_of_variable): Likewise.
+
+2011-09-08  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
        * stack.c (print_frame_args): New variable except.  Wrap
        read_var_value and common_val_print into TRY_CATCH.
 

diff --git a/gdb/findvar.c b/gdb/findvar.c
index 69dc5a0..8e986f1 100644 (file)
--- a/gdb/findvar.c
+++ b/gdb/findvar.c
@@ -409,7 +409,7 @@ symbol_read_needs_frame (struct symbol *sym)
 /* Given a struct symbol for a variable,
    and a stack frame id, read the value of the variable
    and return a (pointer to a) struct value containing the value.
-   If the variable cannot be found, return a zero pointer.  */
+   If the variable cannot be found, throw error.  */
 
 struct value *
 read_var_value (struct symbol *var, struct frame_info *frame)
@@ -477,7 +477,8 @@ read_var_value (struct symbol *var, struct frame_info *frame)
     case LOC_ARG:
       addr = get_frame_args_address (frame);
       if (!addr)
-       return 0;
+       error (_("Unknown argument list address for `%s'."),
+              SYMBOL_PRINT_NAME (var));
       addr += SYMBOL_VALUE (var);
       v = allocate_value_lazy (type);
       break;
@@ -489,7 +490,8 @@ read_var_value (struct symbol *var, struct frame_info *frame)
 
        argref = get_frame_args_address (frame);
        if (!argref)
-         return 0;
+         error (_("Unknown argument list address for `%s'."),
+                SYMBOL_PRINT_NAME (var));
        argref += SYMBOL_VALUE (var);
        ref = value_at (lookup_pointer_type (type), argref);
        addr = value_as_address (ref);
@@ -504,7 +506,8 @@ read_var_value (struct symbol *var, struct frame_info *frame)
       break;
 
     case LOC_TYPEDEF:
-      error (_("Cannot look up value of a typedef"));
+      error (_("Cannot look up value of a typedef `%s'."),
+            SYMBOL_PRINT_NAME (var));
       break;
 
     case LOC_BLOCK:
@@ -530,7 +533,8 @@ read_var_value (struct symbol *var, struct frame_info *frame)
                                          frame);
 
            if (regval == NULL)
-             error (_("Value of register variable not available."));
+             error (_("Value of register variable not available for `%s'."),
+                    SYMBOL_PRINT_NAME (var));
 
            addr = value_as_address (regval);
            v = allocate_value_lazy (type);
@@ -540,7 +544,8 @@ read_var_value (struct symbol *var, struct frame_info *frame)
            regval = value_from_register (type, regno, frame);
 
            if (regval == NULL)
-             error (_("Value of register variable not available."));
+             error (_("Value of register variable not available for `%s'."),
+                    SYMBOL_PRINT_NAME (var));
            return regval;
          }
       }
@@ -561,7 +566,7 @@ read_var_value (struct symbol *var, struct frame_info *frame)
 
        msym = lookup_minimal_symbol (SYMBOL_LINKAGE_NAME (var), NULL, NULL);
        if (msym == NULL)
-         return 0;
+         error (_("No global symbol \"%s\"."), SYMBOL_LINKAGE_NAME (var));
        if (overlay_debugging)
          addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (msym),
                                           SYMBOL_OBJ_SECTION (msym));
@@ -580,7 +585,8 @@ read_var_value (struct symbol *var, struct frame_info *frame)
       return allocate_optimized_out_value (type);
 
     default:
-      error (_("Cannot look up value of a botched symbol."));
+      error (_("Cannot look up value of a botched symbol `%s'."),
+            SYMBOL_PRINT_NAME (var));
       break;
     }
 

diff --git a/gdb/python/py-frame.c b/gdb/python/py-frame.c
index 7efd13f..9143367 100644 (file)
--- a/gdb/python/py-frame.c
+++ b/gdb/python/py-frame.c
@@ -467,14 +467,6 @@ frapy_read_var (PyObject *self, PyObject *args)
     }
   GDB_PY_HANDLE_EXCEPTION (except);
 
-  if (!val)
-    {
-      PyErr_Format (PyExc_ValueError,
-                   _("Variable cannot be found for symbol '%s'."),
-                   SYMBOL_NATURAL_NAME (var));
-      return NULL;
-    }
-
   return value_to_value_object (val);
 }
 

diff --git a/gdb/stack.c b/gdb/stack.c
index 3147f3e..15666ee 100644 (file)
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -330,6 +330,9 @@ print_frame_args (struct symbol *func, struct frame_info *frame,
 
              TRY_CATCH (except, RETURN_MASK_ERROR)
                {
+                 const struct language_defn *language;
+                 struct value_print_options opts;
+
                  /* Avoid value_print because it will deref ref parameters.
                     We just want to print their addresses.  Print ??? for
                     args whose address we do not know.  We pass 2 as
@@ -338,29 +341,21 @@ print_frame_args (struct symbol *func, struct frame_info *frame,
                     recurse.  */
                  val = read_var_value (sym, frame);
 
-                 annotate_arg_value (val == NULL ? NULL : value_type (val));
+                 annotate_arg_value (value_type (val));
 
-                 if (val)
-                   {
-                     const struct language_defn *language;
-                     struct value_print_options opts;
-
-                     /* Use the appropriate language to display our symbol,
-                        unless the user forced the language to a specific
-                        language.  */
-                     if (language_mode == language_mode_auto)
-                       language = language_def (SYMBOL_LANGUAGE (sym));
-                     else
-                       language = current_language;
-
-                     get_raw_print_options (&opts);
-                     opts.deref_ref = 0;
-                     opts.summary = summary;
-                     common_val_print (val, stb->stream, 2, &opts, language);
-                     ui_out_field_stream (uiout, "value", stb);
-                   }
+                 /* Use the appropriate language to display our symbol,
+                    unless the user forced the language to a specific
+                    language.  */
+                 if (language_mode == language_mode_auto)
+                   language = language_def (SYMBOL_LANGUAGE (sym));
                  else
-                   ui_out_text (uiout, "???");
+                   language = current_language;
+
+                 get_raw_print_options (&opts);
+                 opts.deref_ref = 0;
+                 opts.summary = summary;
+                 common_val_print (val, stb->stream, 2, &opts, language);
+                 ui_out_field_stream (uiout, "value", stb);
                }
              if (except.reason < 0)
                {

diff --git a/gdb/valops.c b/gdb/valops.c
index 25e0fc3..32d71cd 100644 (file)
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -1488,7 +1488,6 @@ value_repeat (struct value *arg1, int count)
 struct value *
 value_of_variable (struct symbol *var, struct block *b)
 {
-  struct value *val;
   struct frame_info *frame;
 
   if (!symbol_read_needs_frame (var))
@@ -1509,11 +1508,7 @@ value_of_variable (struct symbol *var, struct block *b)
        }
     }
 
-  val = read_var_value (var, frame);
-  if (!val)
-    error (_("Address of symbol \"%s\" is unknown."), SYMBOL_PRINT_NAME (var));
-
-  return val;
+  return read_var_value (var, frame);
 }
 
 struct value *