2003-11-19 Andrew Cagney <cagney@redhat.com>

	* stack.c (return_command): Handle "void", "legacy" and "unknown
	location" return values separatly.
	* values.c (using_struct_return): Return 0 for a "void" return
	type.  Mention "register_value_being_returned".
	(register_value_being_returned): Mention "using_struct_return".

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 0daf904f5b04850413e6d3e275a04d495e3f3460..58001dba6af76874bf44639e29088e3da06abcb0 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,11 @@
+2003-11-19  Andrew Cagney  <cagney@redhat.com>
+
+       * stack.c (return_command): Handle "void", "legacy" and "unknown
+       location" return values separatly.
+       * values.c (using_struct_return): Return 0 for a "void" return
+       type.  Mention "register_value_being_returned".
+       (register_value_being_returned): Mention "using_struct_return".
+
 2003-11-19  Daniel Jacobowitz  <drow@mvista.com>
 
        * dwarf2read.c (offreg, basereg, isderef, frame_base_reg)

diff --git a/gdb/stack.c b/gdb/stack.c
index dc8733ef157a0d467050c3cf071e80bf32cd6743..db45284727a66834b1eff68ab60e6b1ccc153e9d 100644 (file)
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -1854,33 +1854,33 @@ return_command (char *retval_exp, int from_tty)
       if (VALUE_LAZY (return_value))
        value_fetch_lazy (return_value);
 
-      /* Check that this architecture can handle the function's return
-         type.  In the case of "struct convention", still do the
-         "return", just also warn the user.  */
-      if (gdbarch_return_value_p (current_gdbarch))
+      if (TYPE_CODE (return_type) == TYPE_CODE_VOID)
+       /* If the return-type is "void", don't try to find the
+           return-value's location.  However, do still evaluate the
+           return expression so that, even when the expression result
+           is discarded, side effects such as "return i++" still
+           occure.  */
+       return_value = NULL;
+      else if (!gdbarch_return_value_p (current_gdbarch)
+              && (TYPE_CODE (return_type) == TYPE_CODE_STRUCT
+                  || TYPE_CODE (return_type) == TYPE_CODE_UNION))
        {
-         if (gdbarch_return_value (current_gdbarch, return_type,
-                                   NULL, NULL, NULL)
-             == RETURN_VALUE_STRUCT_CONVENTION)
-           return_value = NULL;
+         /* NOTE: cagney/2003-10-20: Compatibility hack for legacy
+            code.  Old architectures don't expect STORE_RETURN_VALUE
+            to be called with with a small struct that needs to be
+            stored in registers.  Don't start doing it now.  */
+         query_prefix = "\
+A structure or union return type is not supported by this architecture.\n\
+If you continue, the return value that you specified will be ignored.\n";
+         return_value = NULL;
        }
-      else
+      else if (using_struct_return (return_type, 0))
        {
-         /* NOTE: cagney/2003-10-20: The double check is to ensure
-            that the STORE_RETURN_VALUE call, further down, is not
-            applied to a struct or union return-value.  It wasn't
-            allowed previously, so don't start allowing it now.  An
-            ABI that uses "register convention" to return small
-            structures and should implement the "return_value"
-            architecture method.  */
-         if (using_struct_return (return_type, 0)
-             || TYPE_CODE (return_type) == TYPE_CODE_STRUCT
-             || TYPE_CODE (return_type) == TYPE_CODE_UNION)
-           return_value = NULL;
+         query_prefix = "\
+The location at which to store the function's return value is unknown.\n\
+If you continue, the return value that you specified will be ignored.\n";
+         return_value = NULL;
        }
-      if (return_value == NULL)
-       query_prefix = "\
-The location at which to store the function's return value is unknown.\n";
     }
 
   /* Does an interactive user really want to do this?  Include

diff --git a/gdb/values.c b/gdb/values.c
index a8d8480871ab11c1863f1785060dac24479a240e..386e3bfaebcdb16501d1782bdacd44a8c402c3de 100644 (file)
--- a/gdb/values.c
+++ b/gdb/values.c
@@ -1223,7 +1223,7 @@ register_value_being_returned (struct type *valtype, struct regcache *retbuf)
   struct value *val = allocate_value (valtype);
 
   /* If the function returns void, don't bother fetching the return
-     value.  */
+     value.  See also "using_struct_return".  */
   if (TYPE_CODE (valtype) == TYPE_CODE_VOID)
     return val;
 
@@ -1285,6 +1285,11 @@ using_struct_return (struct type *value_type, int gcc_p)
   if (code == TYPE_CODE_ERROR)
     error ("Function return type unknown.");
 
+  if (code == TYPE_CODE_VOID)
+    /* A void return value is never in memory.  See also corresponding
+       code in "register_value_being_returned".  */
+    return 0;
+
   if (!gdbarch_return_value_p (current_gdbarch))
     {
       /* FIXME: cagney/2003-10-01: The below is dead.  Instead an