===================================================================
@@ -5428,6 +5428,19 @@ ix86_eax_live_at_start_p (void)
return REGNO_REG_SET_P (df_get_live_out (ENTRY_BLOCK_PTR), 0);
}
+static bool
+ix86_keep_aggregate_return_pointer (tree fntype)
+{
+ if (lookup_attribute ("keep_aggregate_return_pointer",
+ TYPE_ATTRIBUTES (fntype)))
+ return true;
+ if (lookup_attribute ("dont_keep_aggregate_return_pointer",
+ TYPE_ATTRIBUTES (fntype)))
+ return false;
+
+ return KEEP_AGGREGATE_RETURN_POINTER != 0;
+}
+
/* Value is the number of bytes of arguments automatically
popped when returning from a subroutine call.
FUNDECL is the declaration node of the function (as a tree),
@@ -5472,7 +5485,7 @@ ix86_return_pops_args (tree fundecl, tre
/* Lose any fake structure return argument if it is passed on the stack. */
if (aggregate_value_p (TREE_TYPE (funtype), fundecl)
- && !KEEP_AGGREGATE_RETURN_POINTER)
+ && !ix86_keep_aggregate_return_pointer (funtype))
{
int nregs = ix86_function_regparm (funtype, fundecl);
if (nregs == 0)
@@ -29052,6 +29065,59 @@ x86_order_regs_for_local_alloc (void)
reg_alloc_order [pos++] = 0;
}
+/* Handle a "dont_keep_aggregate_return_pointer" or
+ "keep_aggregate_return_pointer" attribut; arguments as
+ in struct attribute_spec handler. */
+static tree
+ix86_handle_keep_aggregate_return_ptr_attrib (tree *node, tree name,
+ tree args ATTRIBUTE_UNUSED,
+ int flags ATTRIBUTE_UNUSED,
+ bool *no_add_attrs)
+{
+ if (TREE_CODE (*node) != FUNCTION_TYPE
+ && TREE_CODE (*node) != METHOD_TYPE
+ && TREE_CODE (*node) != FIELD_DECL
+ && TREE_CODE (*node) != TYPE_DECL)
+ {
+ warning (OPT_Wattributes, "%qE attribute only applies to functions",
+ name);
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+ if (TARGET_64BIT)
+ {
+ warning (OPT_Wattributes, "%qE attribute only available for 32-bit",
+ name);
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+ if (is_attribute_p ("dont_keep_aggregate_return_pointer", name))
+ {
+ if (lookup_attribute ("keep_aggregate_return_pointer",
+ TYPE_ATTRIBUTES (*node)))
+ {
+ error ("dont_keep_aggregate_return_pointer and "
+ "keep_aggregate_return_pointer attributes "
+ "are not compatible");
+ }
+ return NULL_TREE;
+ }
+ else if (is_attribute_p ("keep_aggregate_return_pointer", name))
+ {
+ if (lookup_attribute ("dont_keep_aggregate_return_pointer",
+ TYPE_ATTRIBUTES (*node)))
+ {
+ error ("keep_aggregate_return_pointer and "
+ "dont_keep_aggregate_return_pointer attributes "
+ "are not compatible");
+ }
+
+ return NULL_TREE;
+ }
+
+ return NULL_TREE;
+}
+
/* Handle a "ms_abi" or "sysv" attribute; arguments as in
struct attribute_spec.handler. */
static tree
@@ -32221,6 +32287,10 @@ static const struct attribute_spec ix86_
{ "ms_abi", 0, 0, false, true, true, ix86_handle_abi_attribute },
{ "sysv_abi", 0, 0, false, true, true, ix86_handle_abi_attribute },
{ "ms_hook_prologue", 0, 0, true, false, false, ix86_handle_fndecl_attribute },
+ { "dont_keep_aggregate_return_pointer", 0, 0, false, true, true,
+ ix86_handle_keep_aggregate_return_ptr_attrib },
+ { "keep_aggregate_return_pointer", 0, 0, false, true, true,
+ ix86_handle_keep_aggregate_return_ptr_attrib },
/* End element. */
{ NULL, 0, 0, false, false, false, NULL }
};
===================================================================
@@ -2823,6 +2823,19 @@ when targeting Windows. On all other sy
Note, the @code{ms_abi} attribute for Windows targets currently requires
the @option{-maccumulate-outgoing-args} option.
+@item dont_keep_aggregate_return_pointer/keep_aggregate_return_pointer
+@cindex @code{dont_keep_aggregate_return_pointer} attribute
+@cindex @code{keep_aggregate_return_pointer} attribute
+
+On 32-bit i?86-*-* targets, you can control by those attributes for
+aggregate return in memory, if the caller is responsible to pop the hidden
+pointer together with the rest of the arguments, or if the callee is responsible
+to pop hidden pointer.
+
+For i?86-netware, the caller pops the stack for the hidden arguments pointing
+to aggregate return value. This differs from the default i386 ABI which assumes
+that the callee pops the stack for hidden pointer.
+
@item ms_hook_prologue
@cindex @code{ms_hook_prologue} attribute
===================================================================
@@ -0,0 +1,28 @@
+/* target/36834 */
+/* Check that, with keep_aggregate_return_pointer attribute, callee does
+ not pop the stack for the implicit pointer arg when returning a large
+ structure in memory. */
+/* { dg-do compile { target i?86-*-* } } */
+
+struct foo {
+ int a;
+ int b;
+ int c;
+ int d;
+};
+
+__attribute__ ((keep_aggregate_return_pointer))
+struct foo
+bar (void)
+{
+ struct foo retval;
+ retval.a = 1;
+ retval.b = 2;
+ retval.c = 3;
+ retval.d = 4;
+ return retval;
+}
+
+/* { dg-final { scan-assembler-not "ret\[ \t\]\\\$4" } } */
+
+
===================================================================
@@ -0,0 +1,28 @@
+/* target/36834 */
+/* Check that, with dont_keep_aggregate_return_pointer attribute, callee
+ pops the stack for the implicit pointer arg when returning a large
+ structure in memory. */
+/* { dg-do compile { target i?86-*-* } } */
+
+struct foo {
+ int a;
+ int b;
+ int c;
+ int d;
+};
+
+__attribute__ ((dont_keep_aggregate_return_pointer))
+struct foo
+bar (void)
+{
+ struct foo retval;
+ retval.a = 1;
+ retval.b = 2;
+ retval.c = 3;
+ retval.d = 4;
+ return retval;
+}
+
+/* { dg-final { scan-assembler "ret\[ \t\]\\\$4" } } */
+
+