From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by sourceware.org (Postfix) with ESMTPS id 9A2843858401 for ; Thu, 2 Feb 2023 08:07:30 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 9A2843858401 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=suse.de Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 01A811FF83; Thu, 2 Feb 2023 08:07:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1675325248; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=M+AZOaMm2pFvz60K8I93Smm7ZulfJvhl0P1FMUUW3Fk=; b=BHCMzAug2rDt6ncj/PWhaFpwFb6t5dmRDNEMsEUQv1FYaYVOKdzc2IE5vyYXYRDe9r+myF Fe4CE87Xf0bH2+T4udv+YTfUTF+upMrKM2hPnOceLB9i/n1ehr9U1K7USWIL9G3RVKdLwq DCMGxD5a3jI0aFe1cf2nXw9cWlRHZyU= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1675325248; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=M+AZOaMm2pFvz60K8I93Smm7ZulfJvhl0P1FMUUW3Fk=; b=JFd6cvu6PxTL2760/9PrHMCZKkgzjjTGOLR82Zun9k4F6hOM2+LDsSkoLb8NHQkIIfzTm/ 0O8g5SeRxN6ZzTCg== Received: from wotan.suse.de (wotan.suse.de [10.160.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id A06932C141; Thu, 2 Feb 2023 08:07:27 +0000 (UTC) Date: Thu, 2 Feb 2023 08:07:27 +0000 (UTC) From: Richard Biener To: Qing Zhao cc: "gcc-patches@gcc.gnu.org" , "siddhesh@gotplt.org" , "keescook@chromium.org" Subject: Re: [PATCH 1/2] Handle component_ref to a structre/union field including flexible array member [PR101832] In-Reply-To: <812910BC-870E-4432-870D-538024F1A510@oracle.com> Message-ID: References: <20230131141140.3610133-1-qing.zhao@oracle.com> <20230131141140.3610133-2-qing.zhao@oracle.com> <812910BC-870E-4432-870D-538024F1A510@oracle.com> User-Agent: Alpine 2.22 (LSU 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Spam-Status: No, score=-11.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Wed, 1 Feb 2023, Qing Zhao wrote: > > > > On Feb 1, 2023, at 6:41 AM, Richard Biener wrote: > > > > On Tue, 31 Jan 2023, Qing Zhao wrote: > > > >> GCC extension accepts the case when a struct with a flexible array member > >> is embedded into another struct (possibly recursively). > >> __builtin_object_size should treat such struct as flexible size per > >> -fstrict-flex-arrays. > >> > >> PR tree-optimization/101832 > >> > >> gcc/ChangeLog: > >> > >> PR tree-optimization/101832 > >> * tree-object-size.cc (flexible_size_type_p): New function. > >> (addr_object_size): Handle structure/union type when it has > >> flexible size. > >> > >> gcc/testsuite/ChangeLog: > >> > >> PR tree-optimization/101832 > >> * gcc.dg/builtin-object-size-pr101832-2.c: New test. > >> * gcc.dg/builtin-object-size-pr101832-3.c: New test. > >> * gcc.dg/builtin-object-size-pr101832-4.c: New test. > >> * gcc.dg/builtin-object-size-pr101832.c: New test. > >> --- > >> .../gcc.dg/builtin-object-size-pr101832-2.c | 135 ++++++++++++++++++ > >> .../gcc.dg/builtin-object-size-pr101832-3.c | 135 ++++++++++++++++++ > >> .../gcc.dg/builtin-object-size-pr101832-4.c | 135 ++++++++++++++++++ > >> .../gcc.dg/builtin-object-size-pr101832.c | 119 +++++++++++++++ > >> gcc/tree-object-size.cc | 115 +++++++++++---- > >> 5 files changed, 611 insertions(+), 28 deletions(-) > >> create mode 100644 gcc/testsuite/gcc.dg/builtin-object-size-pr101832-2.c > >> create mode 100644 gcc/testsuite/gcc.dg/builtin-object-size-pr101832-3.c > >> create mode 100644 gcc/testsuite/gcc.dg/builtin-object-size-pr101832-4.c > >> create mode 100644 gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c > >> > >> diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-2.c b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-2.c > >> new file mode 100644 > >> index 00000000000..f38babc5415 > >> --- /dev/null > >> +++ b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-2.c > >> @@ -0,0 +1,135 @@ > >> +/* PR 101832: > >> + GCC extension accepts the case when a struct with a flexible array member > >> + is embedded into another struct (possibly recursively). > >> + __builtin_object_size will treat such struct as flexible size per > >> + -fstrict-flex-arrays. */ > >> +/* { dg-do run } */ > >> +/* { dg-options "-O2 -fstrict-flex-arrays=1" } */ > >> + > >> +#include > >> + > >> +unsigned n_fails = 0; > >> + > >> +#define expect(p, _v) do { \ > >> + size_t v = _v; \ > >> + if (p == v) \ > >> + printf("ok: %s == %zd\n", #p, p); \ > >> + else {\ > >> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \ > >> + n_fails++; \ > >> + } \ > >> +} while (0); > >> + > >> +struct A { > >> + int n; > >> + char data[];/* Content following header */ > >> +}; > >> + > >> +struct B { > >> + int m; > >> + struct A a; > >> +}; > >> + > >> +struct C { > >> + int q; > >> + struct B b; > >> +}; > >> + > >> +struct A0 { > >> + int n; > >> + char data[0];/* Content following header */ > >> +}; > >> + > >> +struct B0 { > >> + int m; > >> + struct A0 a; > >> +}; > >> + > >> +struct C0 { > >> + int q; > >> + struct B0 b; > >> +}; > >> + > >> +struct A1 { > >> + int n; > >> + char data[1];/* Content following header */ > >> +}; > >> + > >> +struct B1 { > >> + int m; > >> + struct A1 a; > >> +}; > >> + > >> +struct C1 { > >> + int q; > >> + struct B1 b; > >> +}; > >> + > >> +struct An { > >> + int n; > >> + char data[8];/* Content following header */ > >> +}; > >> + > >> +struct Bn { > >> + int m; > >> + struct An a; > >> +}; > >> + > >> +struct Cn { > >> + int q; > >> + struct Bn b; > >> +}; > >> + > >> +volatile void *magic1, *magic2; > >> + > >> +int main(int argc, char *argv[]) > >> +{ > >> + struct B *outer; > >> + struct C *outest; > >> + > >> + /* Make sure optimization can't find some other object size. */ > >> + outer = (void *)magic1; > >> + outest = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outer->a, 1), -1); > >> + expect(__builtin_object_size(&outest->b, 1), -1); > >> + expect(__builtin_object_size(&outest->b.a, 1), -1); > >> + > >> + struct B0 *outer0; > >> + struct C0 *outest0; > >> + > >> + /* Make sure optimization can't find some other object size. */ > >> + outer0 = (void *)magic1; > >> + outest0 = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outer0->a, 1), -1); > >> + expect(__builtin_object_size(&outest0->b, 1), -1); > >> + expect(__builtin_object_size(&outest0->b.a, 1), -1); > >> + > >> + struct B1 *outer1; > >> + struct C1 *outest1; > >> + > >> + /* Make sure optimization can't find some other object size. */ > >> + outer1 = (void *)magic1; > >> + outest1 = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outer1->a, 1), -1); > >> + expect(__builtin_object_size(&outest1->b, 1), -1); > >> + expect(__builtin_object_size(&outest1->b.a, 1), -1); > >> + > >> + struct Bn *outern; > >> + struct Cn *outestn; > >> + > >> + /* Make sure optimization can't find some other object size. */ > >> + outern = (void *)magic1; > >> + outestn = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outern->a, 1), sizeof(outern->a)); > >> + expect(__builtin_object_size(&outestn->b, 1), sizeof(outestn->b)); > >> + expect(__builtin_object_size(&outestn->b.a, 1), sizeof(outestn->b.a)); > >> + > >> + if (n_fails > 0) > >> + __builtin_abort (); > >> + > >> + return 0; > >> +} > >> diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-3.c b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-3.c > >> new file mode 100644 > >> index 00000000000..aaae99b8d67 > >> --- /dev/null > >> +++ b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-3.c > >> @@ -0,0 +1,135 @@ > >> +/* PR 101832: > >> + GCC extension accepts the case when a struct with a flexible array member > >> + is embedded into another struct (possibly recursively). > >> + __builtin_object_size will treat such struct as flexible size per > >> + -fstrict-flex-arrays. */ > >> +/* { dg-do run } */ > >> +/* { dg-options "-O2 -fstrict-flex-arrays=2" } */ > >> + > >> +#include > >> + > >> +unsigned n_fails = 0; > >> + > >> +#define expect(p, _v) do { \ > >> + size_t v = _v; \ > >> + if (p == v) \ > >> + printf("ok: %s == %zd\n", #p, p); \ > >> + else {\ > >> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \ > >> + n_fails++; \ > >> + } \ > >> +} while (0); > >> + > >> +struct A { > >> + int n; > >> + char data[];/* Content following header */ > >> +}; > >> + > >> +struct B { > >> + int m; > >> + struct A a; > >> +}; > >> + > >> +struct C { > >> + int q; > >> + struct B b; > >> +}; > >> + > >> +struct A0 { > >> + int n; > >> + char data[0];/* Content following header */ > >> +}; > >> + > >> +struct B0 { > >> + int m; > >> + struct A0 a; > >> +}; > >> + > >> +struct C0 { > >> + int q; > >> + struct B0 b; > >> +}; > >> + > >> +struct A1 { > >> + int n; > >> + char data[1];/* Content following header */ > >> +}; > >> + > >> +struct B1 { > >> + int m; > >> + struct A1 a; > >> +}; > >> + > >> +struct C1 { > >> + int q; > >> + struct B1 b; > >> +}; > >> + > >> +struct An { > >> + int n; > >> + char data[8];/* Content following header */ > >> +}; > >> + > >> +struct Bn { > >> + int m; > >> + struct An a; > >> +}; > >> + > >> +struct Cn { > >> + int q; > >> + struct Bn b; > >> +}; > >> + > >> +volatile void *magic1, *magic2; > >> + > >> +int main(int argc, char *argv[]) > >> +{ > >> + struct B *outer; > >> + struct C *outest; > >> + > >> + /* Make sure optimization can't find some other object size. */ > >> + outer = (void *)magic1; > >> + outest = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outer->a, 1), -1); > >> + expect(__builtin_object_size(&outest->b, 1), -1); > >> + expect(__builtin_object_size(&outest->b.a, 1), -1); > >> + > >> + struct B0 *outer0; > >> + struct C0 *outest0; > >> + > >> + /* Make sure optimization can't find some other object size. */ > >> + outer0 = (void *)magic1; > >> + outest0 = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outer0->a, 1), -1); > >> + expect(__builtin_object_size(&outest0->b, 1), -1); > >> + expect(__builtin_object_size(&outest0->b.a, 1), -1); > >> + > >> + struct B1 *outer1; > >> + struct C1 *outest1; > >> + > >> + /* Make sure optimization can't find some other object size. */ > >> + outer1 = (void *)magic1; > >> + outest1 = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outer1->a, 1), sizeof(outer1->a)); > >> + expect(__builtin_object_size(&outest1->b, 1), sizeof(outest1->b)); > >> + expect(__builtin_object_size(&outest1->b.a, 1), sizeof(outest1->b.a)); > >> + > >> + struct Bn *outern; > >> + struct Cn *outestn; > >> + > >> + /* Make sure optimization can't find some other object size. */ > >> + outern = (void *)magic1; > >> + outestn = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outern->a, 1), sizeof(outern->a)); > >> + expect(__builtin_object_size(&outestn->b, 1), sizeof(outestn->b)); > >> + expect(__builtin_object_size(&outestn->b.a, 1), sizeof(outestn->b.a)); > >> + > >> + if (n_fails > 0) > >> + __builtin_abort (); > >> + > >> + return 0; > >> +} > >> diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-4.c b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-4.c > >> new file mode 100644 > >> index 00000000000..424264e2acd > >> --- /dev/null > >> +++ b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-4.c > >> @@ -0,0 +1,135 @@ > >> +/* PR 101832: > >> + GCC extension accepts the case when a struct with a flexible array member > >> + is embedded into another struct (possibly recursively). > >> + __builtin_object_size will treat such struct as flexible size per > >> + -fstrict-flex-arrays. */ > >> +/* { dg-do run } */ > >> +/* { dg-options "-O2 -fstrict-flex-arrays=3" } */ > >> + > >> +#include > >> + > >> +unsigned n_fails = 0; > >> + > >> +#define expect(p, _v) do { \ > >> + size_t v = _v; \ > >> + if (p == v) \ > >> + printf("ok: %s == %zd\n", #p, p); \ > >> + else {\ > >> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \ > >> + n_fails++; \ > >> + } \ > >> +} while (0); > >> + > >> +struct A { > >> + int n; > >> + char data[];/* Content following header */ > >> +}; > >> + > >> +struct B { > >> + int m; > >> + struct A a; > >> +}; > >> + > >> +struct C { > >> + int q; > >> + struct B b; > >> +}; > >> + > >> +struct A0 { > >> + int n; > >> + char data[0];/* Content following header */ > >> +}; > >> + > >> +struct B0 { > >> + int m; > >> + struct A0 a; > >> +}; > >> + > >> +struct C0 { > >> + int q; > >> + struct B0 b; > >> +}; > >> + > >> +struct A1 { > >> + int n; > >> + char data[1];/* Content following header */ > >> +}; > >> + > >> +struct B1 { > >> + int m; > >> + struct A1 a; > >> +}; > >> + > >> +struct C1 { > >> + int q; > >> + struct B1 b; > >> +}; > >> + > >> +struct An { > >> + int n; > >> + char data[8];/* Content following header */ > >> +}; > >> + > >> +struct Bn { > >> + int m; > >> + struct An a; > >> +}; > >> + > >> +struct Cn { > >> + int q; > >> + struct Bn b; > >> +}; > >> + > >> +volatile void *magic1, *magic2; > >> + > >> +int main(int argc, char *argv[]) > >> +{ > >> + struct B *outer; > >> + struct C *outest; > >> + > >> + /* Make sure optimization can't find some other object size. */ > >> + outer = (void *)magic1; > >> + outest = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outer->a, 1), -1); > >> + expect(__builtin_object_size(&outest->b, 1), -1); > >> + expect(__builtin_object_size(&outest->b.a, 1), -1); > >> + > >> + struct B0 *outer0; > >> + struct C0 *outest0; > >> + > >> + /* Make sure optimization can't find some other object size. */ > >> + outer0 = (void *)magic1; > >> + outest0 = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outer0->a, 1), sizeof(outer0->a)); > >> + expect(__builtin_object_size(&outest0->b, 1), sizeof(outest0->b)); > >> + expect(__builtin_object_size(&outest0->b.a, 1), sizeof(outest0->b.a)); > >> + > >> + struct B1 *outer1; > >> + struct C1 *outest1; > >> + > >> + /* Make sure optimization can't find some other object size. */ > >> + outer1 = (void *)magic1; > >> + outest1 = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outer1->a, 1), sizeof(outer1->a)); > >> + expect(__builtin_object_size(&outest1->b, 1), sizeof(outest1->b)); > >> + expect(__builtin_object_size(&outest1->b.a, 1), sizeof(outest1->b.a)); > >> + > >> + struct Bn *outern; > >> + struct Cn *outestn; > >> + > >> + /* Make sure optimization can't find some other object size. */ > >> + outern = (void *)magic1; > >> + outestn = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outern->a, 1), sizeof(outern->a)); > >> + expect(__builtin_object_size(&outestn->b, 1), sizeof(outestn->b)); > >> + expect(__builtin_object_size(&outestn->b.a, 1), sizeof(outestn->b.a)); > >> + > >> + if (n_fails > 0) > >> + __builtin_abort (); > >> + > >> + return 0; > >> +} > >> diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c > >> new file mode 100644 > >> index 00000000000..8ed6980edf0 > >> --- /dev/null > >> +++ b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c > >> @@ -0,0 +1,119 @@ > >> +/* PR 101832: > >> + GCC extension accepts the case when a struct with a flexible array member > >> + is embedded into another struct (possibly recursively). > >> + __builtin_object_size will treat such struct as flexible size per > >> + -fstrict-flex-arrays. */ > >> +/* { dg-do run } */ > >> +/* { dg-options "-O2" } */ > >> + > >> +#include > >> + > >> +unsigned n_fails = 0; > >> + > >> +#define expect(p, _v) do { \ > >> + size_t v = _v; \ > >> + if (p == v) \ > >> + printf("ok: %s == %zd\n", #p, p); \ > >> + else {\ > >> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \ > >> + n_fails++; \ > >> + } \ > >> +} while (0); > >> + > >> +struct A { > >> + int n; > >> + char data[];/* Content following header */ > >> +}; > >> + > >> +struct B { > >> + int m; > >> + struct A a; > >> +}; > >> + > >> +struct C { > >> + int q; > >> + struct B b; > >> +}; > >> + > >> +struct A0 { > >> + int n; > >> + char data[0];/* Content following header */ > >> +}; > >> + > >> +struct B0 { > >> + int m; > >> + struct A0 a; > >> +}; > >> + > >> +struct C0 { > >> + int q; > >> + struct B0 b; > >> +}; > >> + > >> +struct A1 { > >> + int n; > >> + char data[1];/* Content following header */ > >> +}; > >> + > >> +struct B1 { > >> + int m; > >> + struct A1 a; > >> +}; > >> + > >> +struct C1 { > >> + int q; > >> + struct B1 b; > >> +}; > >> + > >> +struct An { > >> + int n; > >> + char data[8];/* Content following header */ > >> +}; > >> + > >> +struct Bn { > >> + int m; > >> + struct An a; > >> +}; > >> + > >> +struct Cn { > >> + int q; > >> + struct Bn b; > >> +}; > >> + > >> +volatile void *magic1, *magic2; > >> + > >> +int main(int argc, char *argv[]) > >> +{ > >> + struct B *outer = (void *)magic1; > >> + struct C *outest = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outer->a, 1), -1); > >> + expect(__builtin_object_size(&outest->b, 1), -1); > >> + expect(__builtin_object_size(&outest->b.a, 1), -1); > >> + > >> + struct B0 *outer0 = (void *)magic1; > >> + struct C0 *outest0 = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outer0->a, 1), -1); > >> + expect(__builtin_object_size(&outest0->b, 1), -1); > >> + expect(__builtin_object_size(&outest0->b.a, 1), -1); > >> + > >> + struct B1 *outer1 = (void *)magic1; > >> + struct C1 *outest1 = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outer1->a, 1), -1); > >> + expect(__builtin_object_size(&outest1->b, 1), -1); > >> + expect(__builtin_object_size(&outest1->b.a, 1), -1); > >> + > >> + struct Bn *outern = (void *)magic1; > >> + struct Cn *outestn = (void *)magic2; > >> + > >> + expect(__builtin_object_size(&outern->a, 1), -1); > >> + expect(__builtin_object_size(&outestn->b, 1), -1); > >> + expect(__builtin_object_size(&outestn->b.a, 1), -1); > >> + > >> + if (n_fails > 0) > >> + __builtin_abort (); > >> + > >> + return 0; > >> +} > >> diff --git a/gcc/tree-object-size.cc b/gcc/tree-object-size.cc > >> index 9a936a91983..56b78ca2a8c 100644 > >> --- a/gcc/tree-object-size.cc > >> +++ b/gcc/tree-object-size.cc > >> @@ -500,6 +500,42 @@ decl_init_size (tree decl, bool min) > >> return size; > >> } > >> > >> +/* Determine whether TYPE is a structure with a flexible array member > >> + per -fstrict-flex-array or a union containing such a structure > >> + (possibly recursively). */ > >> +static bool > >> +flexible_size_type_p (const_tree type) > >> +{ > >> + tree x = NULL_TREE; > >> + tree last = NULL_TREE; > >> + switch (TREE_CODE (type)) > >> + { > >> + case RECORD_TYPE: > >> + for (x = TYPE_FIELDS (type); x != NULL_TREE; x = DECL_CHAIN (x)) > >> + if (TREE_CODE (x) == FIELD_DECL) > >> + last = x; > >> + if (last == NULL_TREE) > >> + return false; > >> + if (TREE_CODE (TREE_TYPE (last)) == ARRAY_TYPE > >> + && !DECL_NOT_FLEXARRAY (last)) > >> + return true; > >> + else if (TREE_CODE (TREE_TYPE (last)) == RECORD_TYPE > >> + || TREE_CODE (TREE_TYPE (last)) == UNION_TYPE) > >> + return flexible_size_type_p (TREE_TYPE (last)); > > > > For types with many members this can become quite slow (IIRC we had > > bugs about similar walks of all fields in types), and this function > > looks like it's invoked multiple times on the same type per TU. > > > > In principle the property is fixed at the time we lay out a record > > type, so we might want to compute it at that time and record the > > result. > > You mean in FE? Yes, either in the frontend or in the middle-ends layout_type. > Yes, that?s better and cleaner. > > I will add one more field in the TYPE structure to record this information and check this field during middle end. > > I had the same thought in the beginning, but not sure whether adding a > new field in IR is necessary or not, other places in middle end might > not use this new field. It might be interesting to search for other code walking all fields of a type to determine this or similar info. > thanks. > > Qing > > > > >> + return false; > >> + case UNION_TYPE: > >> + for (x = TYPE_FIELDS (type); x != NULL_TREE; x = DECL_CHAIN (x)) > >> + { > >> + if (TREE_CODE (x) == FIELD_DECL > >> + && flexible_array_type_p (TREE_TYPE (x))) > >> + return true; > >> + } > >> + return false; > >> + default: > >> + return false; > >> + } > >> +} > >> + > >> /* Compute __builtin_object_size for PTR, which is a ADDR_EXPR. > >> OBJECT_SIZE_TYPE is the second argument from __builtin_object_size. > >> If unknown, return size_unknown (object_size_type). */ > >> @@ -633,45 +669,68 @@ addr_object_size (struct object_size_info *osi, const_tree ptr, > >> v = NULL_TREE; > >> break; > >> case COMPONENT_REF: > >> - if (TREE_CODE (TREE_TYPE (v)) != ARRAY_TYPE) > >> + /* When the ref is not to an array, a record or a union, it > >> + will not have flexible size, compute the object size > >> + directly. */ > >> + if ((TREE_CODE (TREE_TYPE (v)) != ARRAY_TYPE) > >> + && (TREE_CODE (TREE_TYPE (v)) != RECORD_TYPE) > >> + && (TREE_CODE (TREE_TYPE (v)) != UNION_TYPE)) > >> { > >> v = NULL_TREE; > >> break; > >> } > >> - is_flexible_array_mem_ref = array_ref_flexible_size_p (v); > >> - while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) > >> - if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) > >> - != UNION_TYPE > >> - && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) > >> - != QUAL_UNION_TYPE) > >> - break; > >> - else > >> - v = TREE_OPERAND (v, 0); > >> - if (TREE_CODE (v) == COMPONENT_REF > >> - && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) > >> - == RECORD_TYPE) > >> + /* if the record or union does not have flexible size > >> + compute the object size directly. */ > >> + if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE > >> + || TREE_CODE (TREE_TYPE (v)) == UNION_TYPE) > >> { > >> - /* compute object size only if v is not a > >> - flexible array member. */ > >> - if (!is_flexible_array_mem_ref) > >> + if (!flexible_size_type_p (TREE_TYPE (v))) > >> { > >> v = NULL_TREE; > >> break; > >> } > >> - v = TREE_OPERAND (v, 0); > >> + else > >> + v = TREE_OPERAND (v, 0); > >> } > >> - while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) > >> - if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) > >> - != UNION_TYPE > >> - && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) > >> - != QUAL_UNION_TYPE) > >> - break; > >> - else > >> - v = TREE_OPERAND (v, 0); > >> - if (v != pt_var) > >> - v = NULL_TREE; > >> else > >> - v = pt_var; > >> + { > >> + /* Now the ref is to an array type. */ > >> + is_flexible_array_mem_ref > >> + = array_ref_flexible_size_p (v); > >> + while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) > >> + if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) > >> + != UNION_TYPE > >> + && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) > >> + != QUAL_UNION_TYPE) > >> + break; > >> + else > >> + v = TREE_OPERAND (v, 0); > >> + if (TREE_CODE (v) == COMPONENT_REF > >> + && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) > >> + == RECORD_TYPE) > >> + { > >> + /* compute object size only if v is not a > >> + flexible array member. */ > >> + if (!is_flexible_array_mem_ref) > >> + { > >> + v = NULL_TREE; > >> + break; > >> + } > >> + v = TREE_OPERAND (v, 0); > >> + } > >> + while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) > >> + if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) > >> + != UNION_TYPE > >> + && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) > >> + != QUAL_UNION_TYPE) > >> + break; > >> + else > >> + v = TREE_OPERAND (v, 0); > >> + if (v != pt_var) > >> + v = NULL_TREE; > >> + else > >> + v = pt_var; > >> + } > >> break; > >> default: > >> v = pt_var; > >> > > > > -- > > Richard Biener > > SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg, > > Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman; > > HRB 36809 (AG Nuernberg) > > -- Richard Biener SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg, Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman; HRB 36809 (AG Nuernberg)