On Wed, Jun 16, 2021 at 9:49 AM Jakub Jelinek <ja...@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 <ja...@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: <jinch...@ca.ibm.com> and <ja...@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
>
