From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTP id 4B95C385783E for ; Tue, 15 Jun 2021 19:02:08 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 4B95C385783E Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-214-w7Iu3GnXMjC0oxRwEp5zkw-1; Tue, 15 Jun 2021 15:02:04 -0400 X-MC-Unique: w7Iu3GnXMjC0oxRwEp5zkw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CA332100C666; Tue, 15 Jun 2021 19:02:03 +0000 (UTC) Received: from tucnak.zalov.cz (ovpn-112-7.ams2.redhat.com [10.36.112.7]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 76DD619814; Tue, 15 Jun 2021 19:02:03 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.16.1/8.16.1) with ESMTPS id 15FJ21hF3107550 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 15 Jun 2021 21:02:01 +0200 Received: (from jakub@localhost) by tucnak.zalov.cz (8.16.1/8.16.1/Submit) id 15FJ20253107549; Tue, 15 Jun 2021 21:02:00 +0200 Date: Tue, 15 Jun 2021 21:02:00 +0200 From: Jakub Jelinek To: Anthony Green , libffi-discuss Subject: Re: Incorrect data detected in the nested float struct with x86/libffi on Linux/64bit Message-ID: <20210615190200.GR7746@tucnak> Reply-To: Jakub Jelinek References: <20210615180256.GQ7746@tucnak> MIME-Version: 1.0 In-Reply-To: <20210615180256.GQ7746@tucnak> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-5.8 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, KAM_SHORT, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libffi-discuss@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libffi-discuss mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Jun 2021 19:02:10 -0000 On Tue, Jun 15, 2021 at 08:02:56PM +0200, Jakub Jelinek via Libffi-discuss wrote: > On Wed, Jun 09, 2021 at 12:50:08PM -0400, Anthony Green wrote: > > Thank you, Cheng. Are you able to submit this test case as a github pull > > request? The resulting CI testing will give us a broader picture of where > > we have problems. > > Comparing gcc/config/i386/ classify_argument and libffi classify_argument, > I found two important differences. > > The first one seems the most important one, even GCC 3.2 included the bit > offset (byte offset in libffi) in the calculation of number of words. > And the other change is https://gcc.gnu.org/PR38781. > > With this patch the posted testcase works and the testsuite on x86_64-linux > still passes, but haven't done more testing than that. > > Haven't tried yet to adapt one of the > libffi/testsuite/libffi.call/nested_struct*.c tests to cover this though. And here is one with a testcase (modified nested_struct2.c for it). I'm unsure about the current relationship between the github and gcc copy of libffi, shall it go to both, or just one of them and be cherry-picked from there? Tested on x86_64-linux. 2021-06-15 Jakub Jelinek * 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. --- 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: and 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