libffi: Fix up x86_64 classify_argument

Message ID 20210616074940.GX7746@tucnak
State New
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Series
  • libffi: Fix up x86_64 classify_argument
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Commit Message

Xionghu Luo via Gcc-patches June 16, 2021, 7:49 a.m.
Hi!

As the following testcase shows, libffi didn't handle properly
classify_arguments of structures at byte offsets not divisible by
UNITS_PER_WORD.  The following patch adjusts it to match what
config/i386/ classify_argument does for that and also ports the
PR38781 fix there (the second chunk).

This has been committed to upstream libffi already:
https://github.com/libffi/libffi/commit/5651bea284ad0822eafe768e3443c2f4d7da2c8f

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2021-06-16  Jakub Jelinek  <jakub@redhat.com>

	* src/x86/ffi64.c (classify_argument): For FFI_TYPE_STRUCT set words
	to number of words needed for type->size + byte_offset bytes rather
	than just type->size bytes.  Compute pos before the loop and check
	total size of the structure.
	* testsuite/libffi.call/nested_struct12.c: New test.


	Jakub

Comments

Xionghu Luo via Gcc-patches June 16, 2021, 8:08 a.m. | #1
On Wed, Jun 16, 2021 at 9:49 AM Jakub Jelinek <jakub@redhat.com> wrote:
>

> Hi!

>

> As the following testcase shows, libffi didn't handle properly

> classify_arguments of structures at byte offsets not divisible by

> UNITS_PER_WORD.  The following patch adjusts it to match what

> config/i386/ classify_argument does for that and also ports the

> PR38781 fix there (the second chunk).

>

> This has been committed to upstream libffi already:

> https://github.com/libffi/libffi/commit/5651bea284ad0822eafe768e3443c2f4d7da2c8f

>

> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

>

> 2021-06-16  Jakub Jelinek  <jakub@redhat.com>

>

>         * src/x86/ffi64.c (classify_argument): For FFI_TYPE_STRUCT set words

>         to number of words needed for type->size + byte_offset bytes rather

>         than just type->size bytes.  Compute pos before the loop and check

>         total size of the structure.

>         * testsuite/libffi.call/nested_struct12.c: New test.


OK.

Thanks,
Uros.

>

> --- libffi/src/x86/ffi64.c.jj   2020-01-14 20:02:48.557583260 +0100

> +++ libffi/src/x86/ffi64.c      2021-06-15 19:50:06.059108230 +0200

> @@ -217,7 +217,8 @@ classify_argument (ffi_type *type, enum

>      case FFI_TYPE_STRUCT:

>        {

>         const size_t UNITS_PER_WORD = 8;

> -       size_t words = (type->size + UNITS_PER_WORD - 1) / UNITS_PER_WORD;

> +       size_t words = (type->size + byte_offset + UNITS_PER_WORD - 1)

> +                      / UNITS_PER_WORD;

>         ffi_type **ptr;

>         int i;

>         enum x86_64_reg_class subclasses[MAX_CLASSES];

> @@ -241,16 +242,16 @@ classify_argument (ffi_type *type, enum

>         /* Merge the fields of structure.  */

>         for (ptr = type->elements; *ptr != NULL; ptr++)

>           {

> -           size_t num;

> +           size_t num, pos;

>

>             byte_offset = ALIGN (byte_offset, (*ptr)->alignment);

>

>             num = classify_argument (*ptr, subclasses, byte_offset % 8);

>             if (num == 0)

>               return 0;

> -           for (i = 0; i < num; i++)

> +           pos = byte_offset / 8;

> +           for (i = 0; i < num && (i + pos) < words; i++)

>               {

> -               size_t pos = byte_offset / 8;

>                 classes[i + pos] =

>                   merge_classes (subclasses[i], classes[i + pos]);

>               }

> --- libffi/testsuite/libffi.call/nested_struct12.c.jj   2021-06-15 20:31:43.327144303 +0200

> +++ libffi/testsuite/libffi.call/nested_struct12.c      2021-06-15 20:47:13.129489263 +0200

> @@ -0,0 +1,107 @@

> +/* Area:       ffi_call, closure_call

> +   Purpose:    Check structure passing.

> +   Limitations:        none.

> +   PR:         none.

> +   Originator: <jincheng@ca.ibm.com> and <jakub@redhat.com> 20210609    */

> +

> +/* { dg-do run } */

> +#include "ffitest.h"

> +

> +typedef struct A {

> +  float a, b;

> +} A;

> +

> +typedef struct B {

> +  float x;

> +  struct A y;

> +} B;

> +

> +B B_fn(float b0, struct B b1)

> +{

> +  struct B result;

> +

> +  result.x = b0 + b1.x;

> +  result.y.a = b0 + b1.y.a;

> +  result.y.b = b0 + b1.y.b;

> +

> +  printf("%g %g %g %g: %g %g %g\n", b0, b1.x, b1.y.a, b1.y.b,

> +        result.x, result.y.a, result.y.b);

> +

> +  return result;

> +}

> +

> +static void

> +B_gn(ffi_cif* cif __UNUSED__, void* resp, void** args,

> +     void* userdata __UNUSED__)

> +{

> +  float b0;

> +  struct B b1;

> +

> +  b0 = *(float*)(args[0]);

> +  b1 = *(struct B*)(args[1]);

> +

> +  *(B*)resp = B_fn(b0, b1);

> +}

> +

> +int main (void)

> +{

> +  ffi_cif cif;

> +  void *code;

> +  ffi_closure *pcl = ffi_closure_alloc(sizeof(ffi_closure), &code);

> +  void* args_dbl[3];

> +  ffi_type* cls_struct_fields[3];

> +  ffi_type* cls_struct_fields1[3];

> +  ffi_type cls_struct_type, cls_struct_type1;

> +  ffi_type* dbl_arg_types[3];

> +

> +  float e_dbl = 12.125f;

> +  struct B f_dbl = { 24.75f, { 31.625f, 32.25f } };

> +

> +  struct B res_dbl;

> +

> +  cls_struct_type.size = 0;

> +  cls_struct_type.alignment = 0;

> +  cls_struct_type.type = FFI_TYPE_STRUCT;

> +  cls_struct_type.elements = cls_struct_fields;

> +

> +  cls_struct_type1.size = 0;

> +  cls_struct_type1.alignment = 0;

> +  cls_struct_type1.type = FFI_TYPE_STRUCT;

> +  cls_struct_type1.elements = cls_struct_fields1;

> +

> +  cls_struct_fields[0] = &ffi_type_float;

> +  cls_struct_fields[1] = &ffi_type_float;

> +  cls_struct_fields[2] = NULL;

> +

> +  cls_struct_fields1[0] = &ffi_type_float;

> +  cls_struct_fields1[1] = &cls_struct_type;

> +  cls_struct_fields1[2] = NULL;

> +

> +

> +  dbl_arg_types[0] = &ffi_type_float;

> +  dbl_arg_types[1] = &cls_struct_type1;

> +  dbl_arg_types[2] = NULL;

> +

> +  CHECK(ffi_prep_cif(&cif, FFI_DEFAULT_ABI, 2, &cls_struct_type1,

> +                    dbl_arg_types) == FFI_OK);

> +

> +  args_dbl[0] = &e_dbl;

> +  args_dbl[1] = &f_dbl;

> +  args_dbl[2] = NULL;

> +

> +  ffi_call(&cif, FFI_FN(B_fn), &res_dbl, args_dbl);

> +  /* { dg-output "12.125 24.75 31.625 32.25: 36.875 43.75 44.375" } */

> +  CHECK( res_dbl.x == (e_dbl + f_dbl.x));

> +  CHECK( res_dbl.y.a == (e_dbl + f_dbl.y.a));

> +  CHECK( res_dbl.y.b == (e_dbl + f_dbl.y.b));

> +

> +  CHECK(ffi_prep_closure_loc(pcl, &cif, B_gn, NULL, code) == FFI_OK);

> +

> +  res_dbl = ((B(*)(float, B))(code))(e_dbl, f_dbl);

> +  /* { dg-output "\n12.125 24.75 31.625 32.25: 36.875 43.75 44.375" } */

> +  CHECK( res_dbl.x == (e_dbl + f_dbl.x));

> +  CHECK( res_dbl.y.a == (e_dbl + f_dbl.y.a));

> +  CHECK( res_dbl.y.b == (e_dbl + f_dbl.y.b));

> +

> +  exit(0);

> +}

>

>         Jakub

>

Patch

--- libffi/src/x86/ffi64.c.jj	2020-01-14 20:02:48.557583260 +0100
+++ libffi/src/x86/ffi64.c	2021-06-15 19:50:06.059108230 +0200
@@ -217,7 +217,8 @@  classify_argument (ffi_type *type, enum
     case FFI_TYPE_STRUCT:
       {
 	const size_t UNITS_PER_WORD = 8;
-	size_t words = (type->size + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
+	size_t words = (type->size + byte_offset + UNITS_PER_WORD - 1)
+		       / UNITS_PER_WORD;
 	ffi_type **ptr;
 	int i;
 	enum x86_64_reg_class subclasses[MAX_CLASSES];
@@ -241,16 +242,16 @@  classify_argument (ffi_type *type, enum
 	/* Merge the fields of structure.  */
 	for (ptr = type->elements; *ptr != NULL; ptr++)
 	  {
-	    size_t num;
+	    size_t num, pos;
 
 	    byte_offset = ALIGN (byte_offset, (*ptr)->alignment);
 
 	    num = classify_argument (*ptr, subclasses, byte_offset % 8);
 	    if (num == 0)
 	      return 0;
-	    for (i = 0; i < num; i++)
+	    pos = byte_offset / 8;
+	    for (i = 0; i < num && (i + pos) < words; i++)
 	      {
-		size_t pos = byte_offset / 8;
 		classes[i + pos] =
 		  merge_classes (subclasses[i], classes[i + pos]);
 	      }
--- libffi/testsuite/libffi.call/nested_struct12.c.jj	2021-06-15 20:31:43.327144303 +0200
+++ libffi/testsuite/libffi.call/nested_struct12.c	2021-06-15 20:47:13.129489263 +0200
@@ -0,0 +1,107 @@ 
+/* Area:	ffi_call, closure_call
+   Purpose:	Check structure passing.
+   Limitations:	none.
+   PR:		none.
+   Originator:	<jincheng@ca.ibm.com> and <jakub@redhat.com> 20210609	 */
+
+/* { dg-do run } */
+#include "ffitest.h"
+
+typedef struct A {
+  float a, b;
+} A;
+
+typedef struct B {
+  float x;
+  struct A y;
+} B;
+
+B B_fn(float b0, struct B b1)
+{
+  struct B result;
+
+  result.x = b0 + b1.x;
+  result.y.a = b0 + b1.y.a;
+  result.y.b = b0 + b1.y.b;
+
+  printf("%g %g %g %g: %g %g %g\n", b0, b1.x, b1.y.a, b1.y.b,
+	 result.x, result.y.a, result.y.b);
+
+  return result;
+}
+
+static void
+B_gn(ffi_cif* cif __UNUSED__, void* resp, void** args,
+     void* userdata __UNUSED__)
+{
+  float b0;
+  struct B b1;
+
+  b0 = *(float*)(args[0]);
+  b1 = *(struct B*)(args[1]);
+
+  *(B*)resp = B_fn(b0, b1);
+}
+
+int main (void)
+{
+  ffi_cif cif;
+  void *code;
+  ffi_closure *pcl = ffi_closure_alloc(sizeof(ffi_closure), &code);
+  void* args_dbl[3];
+  ffi_type* cls_struct_fields[3];
+  ffi_type* cls_struct_fields1[3];
+  ffi_type cls_struct_type, cls_struct_type1;
+  ffi_type* dbl_arg_types[3];
+
+  float e_dbl = 12.125f;
+  struct B f_dbl = { 24.75f, { 31.625f, 32.25f } };
+
+  struct B res_dbl;
+
+  cls_struct_type.size = 0;
+  cls_struct_type.alignment = 0;
+  cls_struct_type.type = FFI_TYPE_STRUCT;
+  cls_struct_type.elements = cls_struct_fields;
+
+  cls_struct_type1.size = 0;
+  cls_struct_type1.alignment = 0;
+  cls_struct_type1.type = FFI_TYPE_STRUCT;
+  cls_struct_type1.elements = cls_struct_fields1;
+
+  cls_struct_fields[0] = &ffi_type_float;
+  cls_struct_fields[1] = &ffi_type_float;
+  cls_struct_fields[2] = NULL;
+
+  cls_struct_fields1[0] = &ffi_type_float;
+  cls_struct_fields1[1] = &cls_struct_type;
+  cls_struct_fields1[2] = NULL;
+
+
+  dbl_arg_types[0] = &ffi_type_float;
+  dbl_arg_types[1] = &cls_struct_type1;
+  dbl_arg_types[2] = NULL;
+
+  CHECK(ffi_prep_cif(&cif, FFI_DEFAULT_ABI, 2, &cls_struct_type1,
+		     dbl_arg_types) == FFI_OK);
+
+  args_dbl[0] = &e_dbl;
+  args_dbl[1] = &f_dbl;
+  args_dbl[2] = NULL;
+
+  ffi_call(&cif, FFI_FN(B_fn), &res_dbl, args_dbl);
+  /* { dg-output "12.125 24.75 31.625 32.25: 36.875 43.75 44.375" } */
+  CHECK( res_dbl.x == (e_dbl + f_dbl.x));
+  CHECK( res_dbl.y.a == (e_dbl + f_dbl.y.a));
+  CHECK( res_dbl.y.b == (e_dbl + f_dbl.y.b));
+
+  CHECK(ffi_prep_closure_loc(pcl, &cif, B_gn, NULL, code) == FFI_OK);
+
+  res_dbl = ((B(*)(float, B))(code))(e_dbl, f_dbl);
+  /* { dg-output "\n12.125 24.75 31.625 32.25: 36.875 43.75 44.375" } */
+  CHECK( res_dbl.x == (e_dbl + f_dbl.x));
+  CHECK( res_dbl.y.a == (e_dbl + f_dbl.y.a));
+  CHECK( res_dbl.y.b == (e_dbl + f_dbl.y.b));
+
+  exit(0);
+}