[pushed] Objective-C, NeXT: Fix messenging non-aggregate return-in-memory.

[Iain Sandoe]

Hi

When a method returns a type that the platform ABI says should be
returned in memory, and that is done by a hidden 'sret' parameter,
the message send calls must be adjusted to inform the runtime that
the sret parameter is present.  As reported in the PR, this is not
working for non-aggregate types that use this mechanism.  The fix
here is to adjust the logic such that all return values that flag
'in memory' are considered to use the mechanism *unless* they
provide a struct_value_rtx *and* the return object is an aggregate.

tested across *darwin* and on x86_64, powerpc64-linux,
pushed to master, thanks
Iain

Signed-off-by: Iain Sandoe <i...@sandoe.co.uk>

PR objc/101718 - Objective-C frontend emits wrong code to call methods 
returning scalar types returned in memory

        PR objc/101718

gcc/objc/ChangeLog:

        * objc-next-runtime-abi-02.c (build_v2_build_objc_method_call):
        Revise for cases where scalar objects use an sret parameter.
        (next_runtime_abi_02_build_objc_method_call): Likwise.
---
 gcc/objc/objc-next-runtime-abi-02.c | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/gcc/objc/objc-next-runtime-abi-02.c 
b/gcc/objc/objc-next-runtime-abi-02.c
index ce831fc34ae..9c35738a95c 100644
--- a/gcc/objc/objc-next-runtime-abi-02.c
+++ b/gcc/objc/objc-next-runtime-abi-02.c
@@ -1739,15 +1739,16 @@ build_v2_build_objc_method_call (int super, tree 
method_prototype,
   /* Param list + 2 slots for object and selector.  */
   vec_alloc (parms, nparm + 2);
 
-  /* If we are returning a struct in memory, and the address
-     of that memory location is passed as a hidden first
-     argument, then change which messenger entry point this
-     expr will call.  NB: Note that sender_cast remains
-     unchanged (it already has a struct return type).  */
-  if (!targetm.calls.struct_value_rtx (0, 0)
-      && (TREE_CODE (ret_type) == RECORD_TYPE
-         || TREE_CODE (ret_type) == UNION_TYPE)
-      && targetm.calls.return_in_memory (ret_type, 0))
+  /* If we are returning an item that must be returned in memory, and the
+     target ABI does this by an invisible pointer provided as the first arg,
+     we need to adjust the message signature to include this.  The second
+     part of this excludes targets that provide some alternate scheme for
+     structure returns.  */
+  if (ret_type && !VOID_TYPE_P (ret_type)
+      && targetm.calls.return_in_memory (ret_type, 0)
+      && !(targetm.calls.struct_value_rtx (0, 0)
+          && (TREE_CODE (ret_type) == RECORD_TYPE
+              || TREE_CODE (ret_type) == UNION_TYPE)))
     {
       if (super)
        sender = umsg_id_super2_stret_fixup_decl;
@@ -1849,10 +1850,12 @@ next_runtime_abi_02_build_objc_method_call (location_t 
loc,
             ? TREE_VALUE (TREE_TYPE (method_prototype))
             : objc_object_type;
 
-  if (!targetm.calls.struct_value_rtx (0, 0)
-      && (TREE_CODE (ret_type) == RECORD_TYPE
-         || TREE_CODE (ret_type) == UNION_TYPE)
-      && targetm.calls.return_in_memory (ret_type, 0))
+  /* See comment for the fixup version above.  */
+  if (ret_type && !VOID_TYPE_P (ret_type)
+      && targetm.calls.return_in_memory (ret_type, 0)
+      && !(targetm.calls.struct_value_rtx (0, 0)
+          && (TREE_CODE (ret_type) == RECORD_TYPE
+              || TREE_CODE (ret_type) == UNION_TYPE)))
     {
       if (super)
        message_func_decl = umsg_id_super2_stret_fixup_decl;
--