Merge pull request #407 from trofi/ia64-small-struct

ia64: fix small struct return

src/ia64/unix.S

@@ -175,7 +175,6 @@ ffi_call_unix:
 	;;
 
 .Lst_small_struct:
-	add	sp = -16, sp
 	cmp.lt	p6, p0 = 8, in3
 	cmp.lt	p7, p0 = 16, in3
 	cmp.lt	p8, p0 = 24, in3
@@ -191,6 +190,12 @@ ffi_call_unix:
 (p8)	st8	[r18] = r11
 	mov	out1 = sp
 	mov	out2 = in3
+	;;
+	// ia64 software calling convention requires
+	// top 16 bytes of stack to be scratch space
+	// PLT resolver uses that scratch space at
+	// 'memcpy' symbol reolution time
+	add	sp = -16, sp
 	br.call.sptk.many b0 = memcpy#
 	;;
 	mov	ar.pfs = loc0

testsuite/Makefile.am

@@ -68,6 +68,7 @@ libffi.call/float4.c \
 libffi.call/return_ldl.c \
 libffi.call/closure_fn5.c \
 libffi.call/struct6.c libffi.call/return_ll.c libffi.call/struct9.c	\
+libffi.call/struct10.c \
 libffi.call/return_sc.c libffi.call/struct7.c				\
 libffi.call/cls_align_uint64.c libffi.call/cls_4byte.c			\
 libffi.call/cls_6_1_byte.c			\

testsuite/libffi.call/struct10.c

@@ -0,0 +1,57 @@
+/* Area:	ffi_call
+   Purpose:	Check structures.
+   Limitations:	none.
+   PR:		none.
+   Originator:	Sergei Trofimovich <slyfox@gentoo.org>
+
+   The test originally discovered in ruby's bindings
+   for ffi in https://bugs.gentoo.org/634190  */
+
+/* { dg-do run } */
+#include "ffitest.h"
+
+struct s {
+  int s32;
+  float f32;
+  signed char s8;
+};
+
+struct s make_s(void) {
+  struct s r;
+  r.s32 = 0x1234;
+  r.f32 = 7.0;
+  r.s8  = 0x78;
+  return r;
+}
+
+int main() {
+  ffi_cif cif;
+  struct s r;
+  ffi_type rtype;
+  ffi_type* s_fields[] = {
+    &ffi_type_sint,
+    &ffi_type_float,
+    &ffi_type_schar,
+    NULL,
+  };
+
+  rtype.size      = 0;
+  rtype.alignment = 0,
+  rtype.type      = FFI_TYPE_STRUCT,
+  rtype.elements  = s_fields,
+
+  r.s32 = 0xbad;
+  r.f32 = 999.999;
+  r.s8  = 0x51;
+
+  // Here we emulate the following call:
+  //r = make_s();
+
+  CHECK(ffi_prep_cif(&cif, FFI_DEFAULT_ABI, 0, &rtype, NULL) == FFI_OK);
+  ffi_call(&cif, FFI_FN(make_s), &r, NULL);
+
+  CHECK(r.s32 == 0x1234);
+  CHECK(r.f32 == 7.0);
+  CHECK(r.s8  == 0x78);
+  exit(0);
+}