From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by sourceware.org (Postfix) with ESMTPS id B6D533858D39 for ; Fri, 26 Aug 2022 08:49:40 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org B6D533858D39 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-out1.suse.de (Postfix) with ESMTP id D839133707; Fri, 26 Aug 2022 08:49:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1661503779; 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=pY9VOxFrO9P619oNy41cbIoeuzRkkTSEKxzID9XqdXo=; b=l+Ylg/Gj7lu6BeFC48G6ri8zKbR6QngZ0At8F8euIE4SxiPHVL4IV3nbb8fRP67Ns95maE 3iduDV6u/kOIrhqmoywdrK8BLOcJwxGqMMfl7xUPCXc8PDqA1gWrCgR3ZRA5EWbq9K+XFu 0wpg82aZHCYOXOr7ooIcSwSQRslM6IU= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1661503779; 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=pY9VOxFrO9P619oNy41cbIoeuzRkkTSEKxzID9XqdXo=; b=U5m8vKTyWLVTKr+WU6TAm2jlcNBB8aN/VTOaKr3Mi/mAy7lBiTV2TM0M8EWnHz35Fl4lEX WDbadIbf0Z5RgeDA== 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 CE7062C141; Fri, 26 Aug 2022 08:49:39 +0000 (UTC) Date: Fri, 26 Aug 2022 08:49:39 +0000 (UTC) From: Richard Biener To: Qing Zhao cc: gcc-patches@gcc.gnu.org, jakub@redhat.com, msebor@gmail.com, keescook@chromium.org, joseph@codesourcery.com Subject: Re: [[GCC13][Patch][V3] 2/2] Use array_at_struct_end_p in __builtin_object_size [PR101836] In-Reply-To: <20220817144042.2931674-2-qing.zhao@oracle.com> Message-ID: References: <20220817144042.2931674-1-qing.zhao@oracle.com> <20220817144042.2931674-2-qing.zhao@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=-11.0 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,T_SCC_BODY_TEXT_LINE 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, 17 Aug 2022, Qing Zhao wrote: > Use array_at_struct_end_p to determine whether the trailing array > of a structure is flexible array member in __builtin_object_size. With the discussion about what array_at_struct_end_p actually computes, is this now the correct utility for __builtin_object_size or should it use a stricter variant? > gcc/ChangeLog: > > PR tree-optimization/101836 > * tree-object-size.cc (addr_object_size): Use array_at_struct_end_p > to determine a flexible array member reference. > > gcc/testsuite/ChangeLog: > > PR tree-optimization/101836 > * gcc.dg/pr101836.c: New test. > * gcc.dg/pr101836_1.c: New test. > * gcc.dg/pr101836_2.c: New test. > * gcc.dg/pr101836_3.c: New test. > * gcc.dg/pr101836_4.c: New test. > * gcc.dg/pr101836_5.c: New test. > * gcc.dg/strict-flex-array-5.c: New test. > * gcc.dg/strict-flex-array-6.c: New test. > --- > gcc/testsuite/gcc.dg/pr101836.c | 60 ++++++++++++++++++++++ > gcc/testsuite/gcc.dg/pr101836_1.c | 60 ++++++++++++++++++++++ > gcc/testsuite/gcc.dg/pr101836_2.c | 60 ++++++++++++++++++++++ > gcc/testsuite/gcc.dg/pr101836_3.c | 60 ++++++++++++++++++++++ > gcc/testsuite/gcc.dg/pr101836_4.c | 60 ++++++++++++++++++++++ > gcc/testsuite/gcc.dg/pr101836_5.c | 60 ++++++++++++++++++++++ > gcc/testsuite/gcc.dg/strict-flex-array-5.c | 60 ++++++++++++++++++++++ > gcc/testsuite/gcc.dg/strict-flex-array-6.c | 60 ++++++++++++++++++++++ > gcc/tree-object-size.cc | 16 +++--- > 9 files changed, 487 insertions(+), 9 deletions(-) > create mode 100644 gcc/testsuite/gcc.dg/pr101836.c > create mode 100644 gcc/testsuite/gcc.dg/pr101836_1.c > create mode 100644 gcc/testsuite/gcc.dg/pr101836_2.c > create mode 100644 gcc/testsuite/gcc.dg/pr101836_3.c > create mode 100644 gcc/testsuite/gcc.dg/pr101836_4.c > create mode 100644 gcc/testsuite/gcc.dg/pr101836_5.c > create mode 100644 gcc/testsuite/gcc.dg/strict-flex-array-5.c > create mode 100644 gcc/testsuite/gcc.dg/strict-flex-array-6.c > > diff --git a/gcc/testsuite/gcc.dg/pr101836.c b/gcc/testsuite/gcc.dg/pr101836.c > new file mode 100644 > index 000000000000..efad02cfe899 > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/pr101836.c > @@ -0,0 +1,60 @@ > +/* -fstrict-flex-arrays is aliased with -ftrict-flex-arrays=3, which is the > + strictest, only [] is treated as flexible array. */ > +/* PR tree-optimization/101836 */ > +/* { dg-do run } */ > +/* { dg-options "-O2 -fstrict-flex-arrays" } */ > + > +#include > + > +#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); \ > + __builtin_abort (); \ > + } \ > +} while (0); > + > +struct trailing_array_1 { > + int a; > + int b; > + int c[4]; > +}; > + > +struct trailing_array_2 { > + int a; > + int b; > + int c[1]; > +}; > + > +struct trailing_array_3 { > + int a; > + int b; > + int c[0]; > +}; > +struct trailing_array_4 { > + int a; > + int b; > + int c[]; > +}; > + > +void __attribute__((__noinline__)) stuff( > + struct trailing_array_1 *normal, > + struct trailing_array_2 *trailing_1, > + struct trailing_array_3 *trailing_0, > + struct trailing_array_4 *trailing_flex) > +{ > + expect(__builtin_object_size(normal->c, 1), 16); > + expect(__builtin_object_size(trailing_1->c, 1), 4); > + expect(__builtin_object_size(trailing_0->c, 1), 0); > + expect(__builtin_object_size(trailing_flex->c, 1), -1); > +} > + > +int main(int argc, char *argv[]) > +{ > + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]); > + > + return 0; > +} > diff --git a/gcc/testsuite/gcc.dg/pr101836_1.c b/gcc/testsuite/gcc.dg/pr101836_1.c > new file mode 100644 > index 000000000000..e2931ce1012e > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/pr101836_1.c > @@ -0,0 +1,60 @@ > +/* -fstrict-flex-arrays=3 is the strictest, only [] is treated as > + flexible array. */ > +/* PR tree-optimization/101836 */ > +/* { dg-do run } */ > +/* { dg-options "-O2 -fstrict-flex-arrays=3" } */ > + > +#include > + > +#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); \ > + __builtin_abort (); \ > + } \ > +} while (0); > + > +struct trailing_array_1 { > + int a; > + int b; > + int c[4]; > +}; > + > +struct trailing_array_2 { > + int a; > + int b; > + int c[1]; > +}; > + > +struct trailing_array_3 { > + int a; > + int b; > + int c[0]; > +}; > +struct trailing_array_4 { > + int a; > + int b; > + int c[]; > +}; > + > +void __attribute__((__noinline__)) stuff( > + struct trailing_array_1 *normal, > + struct trailing_array_2 *trailing_1, > + struct trailing_array_3 *trailing_0, > + struct trailing_array_4 *trailing_flex) > +{ > + expect(__builtin_object_size(normal->c, 1), 16); > + expect(__builtin_object_size(trailing_1->c, 1), 4); > + expect(__builtin_object_size(trailing_0->c, 1), 0); > + expect(__builtin_object_size(trailing_flex->c, 1), -1); > +} > + > +int main(int argc, char *argv[]) > +{ > + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]); > + > + return 0; > +} > diff --git a/gcc/testsuite/gcc.dg/pr101836_2.c b/gcc/testsuite/gcc.dg/pr101836_2.c > new file mode 100644 > index 000000000000..78974187721f > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/pr101836_2.c > @@ -0,0 +1,60 @@ > +/* When -fstrict-flex-arrays=2, only [] and [0] are treated as flexiable > + arrays. */ > +/* PR tree-optimization/101836 */ > +/* { dg-do run } */ > +/* { dg-options "-O2 -fstrict-flex-arrays=2" } */ > + > +#include > + > +#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); \ > + __builtin_abort (); \ > + } \ > +} while (0); > + > +struct trailing_array_1 { > + int a; > + int b; > + int c[4]; > +}; > + > +struct trailing_array_2 { > + int a; > + int b; > + int c[1]; > +}; > + > +struct trailing_array_3 { > + int a; > + int b; > + int c[0]; > +}; > +struct trailing_array_4 { > + int a; > + int b; > + int c[]; > +}; > + > +void __attribute__((__noinline__)) stuff( > + struct trailing_array_1 *normal, > + struct trailing_array_2 *trailing_1, > + struct trailing_array_3 *trailing_0, > + struct trailing_array_4 *trailing_flex) > +{ > + expect(__builtin_object_size(normal->c, 1), 16); > + expect(__builtin_object_size(trailing_1->c, 1), 4); > + expect(__builtin_object_size(trailing_0->c, 1), -1); > + expect(__builtin_object_size(trailing_flex->c, 1), -1); > +} > + > +int main(int argc, char *argv[]) > +{ > + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]); > + > + return 0; > +} > diff --git a/gcc/testsuite/gcc.dg/pr101836_3.c b/gcc/testsuite/gcc.dg/pr101836_3.c > new file mode 100644 > index 000000000000..0e69388e81fb > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/pr101836_3.c > @@ -0,0 +1,60 @@ > +/* When -fstrict-flex-arrays=1, [], [0], and [1] are treated as flexible > + arrays. */ > +/* PR tree-optimization/101836 */ > +/* { dg-do run } */ > +/* { dg-options "-O2 -fstrict-flex-arrays=1" } */ > + > +#include > + > +#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); \ > + __builtin_abort (); \ > + } \ > +} while (0); > + > +struct trailing_array_1 { > + int a; > + int b; > + int c[4]; > +}; > + > +struct trailing_array_2 { > + int a; > + int b; > + int c[1]; > +}; > + > +struct trailing_array_3 { > + int a; > + int b; > + int c[0]; > +}; > +struct trailing_array_4 { > + int a; > + int b; > + int c[]; > +}; > + > +void __attribute__((__noinline__)) stuff( > + struct trailing_array_1 *normal, > + struct trailing_array_2 *trailing_1, > + struct trailing_array_3 *trailing_0, > + struct trailing_array_4 *trailing_flex) > +{ > + expect(__builtin_object_size(normal->c, 1), 16); > + expect(__builtin_object_size(trailing_1->c, 1), -1); > + expect(__builtin_object_size(trailing_0->c, 1), -1); > + expect(__builtin_object_size(trailing_flex->c, 1), -1); > +} > + > +int main(int argc, char *argv[]) > +{ > + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]); > + > + return 0; > +} > diff --git a/gcc/testsuite/gcc.dg/pr101836_4.c b/gcc/testsuite/gcc.dg/pr101836_4.c > new file mode 100644 > index 000000000000..e0025aa9a7b5 > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/pr101836_4.c > @@ -0,0 +1,60 @@ > +/* when -fstrict-flex-arrays=0, all trailing arrays are treated as > + flexible arrays. */ > +/* PR tree-optimization/101836 */ > +/* { dg-do run } */ > +/* { dg-options "-O2 -fstrict-flex-arrays=0" } */ > + > +#include > + > +#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); \ > + __builtin_abort (); \ > + } \ > +} while (0); > + > +struct trailing_array_1 { > + int a; > + int b; > + int c[4]; > +}; > + > +struct trailing_array_2 { > + int a; > + int b; > + int c[1]; > +}; > + > +struct trailing_array_3 { > + int a; > + int b; > + int c[0]; > +}; > +struct trailing_array_4 { > + int a; > + int b; > + int c[]; > +}; > + > +void __attribute__((__noinline__)) stuff( > + struct trailing_array_1 *normal, > + struct trailing_array_2 *trailing_1, > + struct trailing_array_3 *trailing_0, > + struct trailing_array_4 *trailing_flex) > +{ > + expect(__builtin_object_size(normal->c, 1), -1); > + expect(__builtin_object_size(trailing_1->c, 1), -1); > + expect(__builtin_object_size(trailing_0->c, 1), -1); > + expect(__builtin_object_size(trailing_flex->c, 1), -1); > +} > + > +int main(int argc, char *argv[]) > +{ > + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]); > + > + return 0; > +} > diff --git a/gcc/testsuite/gcc.dg/pr101836_5.c b/gcc/testsuite/gcc.dg/pr101836_5.c > new file mode 100644 > index 000000000000..0ad8bbf693ce > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/pr101836_5.c > @@ -0,0 +1,60 @@ > +/* -fno-strict-flex-arrays is aliased to -fstrict-flex-arrays=0, > + all trailing arrays are treated as flexible array. */ > +/* PR tree-optimization/101836 */ > +/* { dg-do run } */ > +/* { dg-options "-O2 -fno-strict-flex-arrays" } */ > + > +#include > + > +#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); \ > + __builtin_abort (); \ > + } \ > +} while (0); > + > +struct trailing_array_1 { > + int a; > + int b; > + int c[4]; > +}; > + > +struct trailing_array_2 { > + int a; > + int b; > + int c[1]; > +}; > + > +struct trailing_array_3 { > + int a; > + int b; > + int c[0]; > +}; > +struct trailing_array_4 { > + int a; > + int b; > + int c[]; > +}; > + > +void __attribute__((__noinline__)) stuff( > + struct trailing_array_1 *normal, > + struct trailing_array_2 *trailing_1, > + struct trailing_array_3 *trailing_0, > + struct trailing_array_4 *trailing_flex) > +{ > + expect(__builtin_object_size(normal->c, 1), -1); > + expect(__builtin_object_size(trailing_1->c, 1), -1); > + expect(__builtin_object_size(trailing_0->c, 1), -1); > + expect(__builtin_object_size(trailing_flex->c, 1), -1); > +} > + > +int main(int argc, char *argv[]) > +{ > + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]); > + > + return 0; > +} > diff --git a/gcc/testsuite/gcc.dg/strict-flex-array-5.c b/gcc/testsuite/gcc.dg/strict-flex-array-5.c > new file mode 100644 > index 000000000000..e474b9ec43fa > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/strict-flex-array-5.c > @@ -0,0 +1,60 @@ > +/* test the combination of attribute strict_flex_arrays and option > + -fstrict-flex-arrays: when both attribute and option specified, > + attribute will have higher priority. */ > +/* { dg-do run } */ > +/* { dg-options "-O2 -fstrict-flex-arrays=3" } */ > + > +#include > + > +#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); \ > + __builtin_abort (); \ > + } \ > +} while (0); > + > +struct trailing_array_1 { > + int a; > + int b; > + int c[4] __attribute__ ((strict_flex_arrays (0))); > +}; > + > +struct trailing_array_2 { > + int a; > + int b; > + int c[1] __attribute__ ((strict_flex_arrays (1))); > +}; > + > +struct trailing_array_3 { > + int a; > + int b; > + int c[0] __attribute__ ((strict_flex_arrays (2))); > +}; > +struct trailing_array_4 { > + int a; > + int b; > + int c[]; > +}; > + > +void __attribute__((__noinline__)) stuff( > + struct trailing_array_1 *normal, > + struct trailing_array_2 *trailing_1, > + struct trailing_array_3 *trailing_0, > + struct trailing_array_4 *trailing_flex) > +{ > + expect(__builtin_object_size(normal->c, 1), -1); > + expect(__builtin_object_size(trailing_1->c, 1), -1); > + expect(__builtin_object_size(trailing_0->c, 1), -1); > + expect(__builtin_object_size(trailing_flex->c, 1), -1); > +} > + > +int main(int argc, char *argv[]) > +{ > + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]); > + > + return 0; > +} > diff --git a/gcc/testsuite/gcc.dg/strict-flex-array-6.c b/gcc/testsuite/gcc.dg/strict-flex-array-6.c > new file mode 100644 > index 000000000000..b45e7b32f6d1 > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/strict-flex-array-6.c > @@ -0,0 +1,60 @@ > +/* test the combination of attribute strict_flex_arrays and option > + -fstrict-flex-arrays: when both attribute and option specified, > + attribute will have higher priority. */ > +/* { dg-do run } */ > +/* { dg-options "-O2 -fstrict-flex-arrays=0" } */ > + > +#include > + > +#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); \ > + __builtin_abort (); \ > + } \ > +} while (0); > + > +struct trailing_array_1 { > + int a; > + int b; > + int c[4] __attribute__ ((strict_flex_arrays (1))); > +}; > + > +struct trailing_array_2 { > + int a; > + int b; > + int c[1] __attribute__ ((strict_flex_arrays (2))); > +}; > + > +struct trailing_array_3 { > + int a; > + int b; > + int c[0] __attribute__ ((strict_flex_arrays (3))); > +}; > +struct trailing_array_4 { > + int a; > + int b; > + int c[]; > +}; > + > +void __attribute__((__noinline__)) stuff( > + struct trailing_array_1 *normal, > + struct trailing_array_2 *trailing_1, > + struct trailing_array_3 *trailing_0, > + struct trailing_array_4 *trailing_flex) > +{ > + expect(__builtin_object_size(normal->c, 1), 16); > + expect(__builtin_object_size(trailing_1->c, 1), 4); > + expect(__builtin_object_size(trailing_0->c, 1), 0); > + expect(__builtin_object_size(trailing_flex->c, 1), -1); > +} > + > +int main(int argc, char *argv[]) > +{ > + stuff((void *)argv[0], (void *)argv[0], (void *)argv[0], (void *)argv[0]); > + > + return 0; > +} > diff --git a/gcc/tree-object-size.cc b/gcc/tree-object-size.cc > index 4eb454a4a33b..1f04cb80fd0a 100644 > --- a/gcc/tree-object-size.cc > +++ b/gcc/tree-object-size.cc > @@ -604,9 +604,9 @@ addr_object_size (struct object_size_info *osi, const_tree ptr, > else if (var != pt_var && TREE_CODE (pt_var) == MEM_REF) > { > tree v = var; > - /* For &X->fld, compute object size only if fld isn't the last > - field, as struct { int i; char c[1]; } is often used instead > - of flexible array member. */ > + /* For &X->fld, compute object size if fld isn't a flexible array > + member. */ > + bool is_flexible_array_mem_ref = false; > while (v && v != pt_var) > switch (TREE_CODE (v)) > { > @@ -633,6 +633,7 @@ addr_object_size (struct object_size_info *osi, const_tree ptr, > v = NULL_TREE; > break; > } > + is_flexible_array_mem_ref = array_at_struct_end_p (v); > while (v != pt_var && TREE_CODE (v) == COMPONENT_REF) > if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) > != UNION_TYPE > @@ -645,12 +646,9 @@ addr_object_size (struct object_size_info *osi, const_tree ptr, > && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0))) > == RECORD_TYPE) > { > - tree fld_chain = DECL_CHAIN (TREE_OPERAND (v, 1)); > - for (; fld_chain; fld_chain = DECL_CHAIN (fld_chain)) > - if (TREE_CODE (fld_chain) == FIELD_DECL) > - break; > - > - if (fld_chain) > + /* compute object size only if v is not a > + flexible array member. */ > + if (!is_flexible_array_mem_ref) > { > v = NULL_TREE; > break; > -- 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)