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[71.218.14.121]) by smtp.gmail.com with ESMTPSA id n15sm14751384qti.51.2021.05.11.12.49.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 11 May 2021 12:49:59 -0700 (PDT) To: Richard Biener , gcc-patches Subject: [PATCH] avoid a couple of missing -Wuninitialized (PR 98583, 93100) Message-ID: Date: Tue, 11 May 2021 13:49:58 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 Content-Language: en-US X-Spam-Status: No, score=-10.3 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, 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: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Martin Sebor via Gcc-patches From: Martin Sebor Reply-To: Martin Sebor Errors-To: gcc-patches-bounces@gcc.gnu.org Sender: "Gcc-patches" The attached change teaches the uninitialized pass about __builtin_stack_restore and __builtin___asan_mark to avoid two classes of -Wuninitialized false negatives. Richard, you already approved the __builtin_stack_restore change in the bug but I figured I'd submit a patch with both changes for approval since they affect the same piece of code. Martin Avoid -Wuninitialized false negatives with sanitization and VLAs. Resolves: PR tree-optimization/93100 - gcc -fsanitize=address inhibits -Wuninitialized PR middle-end/98583 - missing -Wuninitialized reading from a second VLA in its own block gcc/ChangeLog: PR tree-optimization/93100 PR middle-end/98583 * tree-ssa-uninit.c (check_defs): gcc/testsuite/ChangeLog: PR tree-optimization/93100 PR middle-end/98583 * g++.dg/warn/uninit-pr93100.C: New test. * gcc.dg/uninit-pr93100.c: New test. * gcc.dg/uninit-pr98583.c: New test. diff --git a/gcc/testsuite/g++.dg/warn/uninit-pr93100.C b/gcc/testsuite/g++.dg/warn/uninit-pr93100.C new file mode 100644 index 00000000000..c9cd3ef0174 --- /dev/null +++ b/gcc/testsuite/g++.dg/warn/uninit-pr93100.C @@ -0,0 +1,59 @@ +/* PR tree-optimization/98508 - Sanitizer disable -Wall and -Wextra + { dg-do compile } + { dg-options "-O0 -Wall -fsanitize=address" } */ + +struct S +{ + int a; +}; + +void warn_init_self_O0 () +{ + S s = S (s); // { dg-warning "\\\[-Wuninitialized" } + (void)&s; +} + + +void warn_init_self_use_O0 () +{ + S s = S (s); // { dg-warning "\\\[-Wuninitialized" } + + void sink (void*); + sink (&s); +} + + +#pragma GCC optimize ("1") + +void warn_init_self_O1 () +{ + S s = S (s); // { dg-warning "\\\[-Wuninitialized" } + (void)&s; +} + + +void warn_init_self_use_O1 () +{ + S s = S (s); // { dg-warning "\\\[-Wuninitialized" } + + void sink (void*); + sink (&s); +} + + +#pragma GCC optimize ("2") + +void warn_init_self_O2 () +{ + S s = S (s); // { dg-warning "\\\[-Wuninitialized" } + (void)&s; +} + + +void warn_init_self_use_O2 () +{ + S s = S (s); // { dg-warning "\\\[-Wuninitialized" } + + void sink (void*); + sink (&s); +} diff --git a/gcc/testsuite/gcc.dg/uninit-pr93100.c b/gcc/testsuite/gcc.dg/uninit-pr93100.c new file mode 100644 index 00000000000..61b7e434038 --- /dev/null +++ b/gcc/testsuite/gcc.dg/uninit-pr93100.c @@ -0,0 +1,74 @@ +/* PR tree-optimization/93100 - gcc -fsanitize=address inhibits -Wuninitialized + { dg-do compile } + { dg-options "-Wall -fsanitize=address" } */ + +struct A +{ + _Bool b; + int i; +}; + +void warn_A_b_O0 (void) +{ + struct A a; + + if (a.b) // { dg-warning "\\\[-Wuninitialized" } + { + (void)&a; + } +} + +void warn_A_i_O0 (void) +{ + struct A a; + + if (a.i) // { dg-warning "\\\[-Wuninitialized" } + { + (void)&a; + } +} + +#pragma GCC optimize ("1") + +void warn_A_b_O1 (void) +{ + struct A a; + + if (a.b) // { dg-warning "\\\[-Wuninitialized" } + { + (void)&a; + } +} + +void warn_A_i_O1 (void) +{ + struct A a; + + if (a.i) // { dg-warning "\\\[-Wuninitialized" } + { + (void)&a; + } +} + + +#pragma GCC optimize ("2") + +void warn_A_b_O2 (void) +{ + struct A a; + + if (a.b) // { dg-warning "\\\[-Wuninitialized" } + { + (void)&a; + } +} + +void warn_A_i_O2 (void) +{ + struct A a; + + if (a.i) // { dg-warning "\\\[-Wuninitialized" } + { + (void)&a; + } +} diff --git a/gcc/testsuite/gcc.dg/uninit-pr98583.c b/gcc/testsuite/gcc.dg/uninit-pr98583.c new file mode 100644 index 00000000000..638b0295809 --- /dev/null +++ b/gcc/testsuite/gcc.dg/uninit-pr98583.c @@ -0,0 +1,31 @@ +/* PR middle-end/98583 - missing -Wuninitialized reading from a second VLA + in its own block + { dg-do compile } + { dg-options "-O2 -Wall" } */ + +void f (int*); +void g (int); + +void h1 (int n) +{ + int a[n]; + f (a); + + int b[n]; + g (b[1]); // { dg-warning "\\\[-Wuninitialized" } +} + +void h2 (int n, int i, int j) +{ + if (i) + { + int a[n]; + f (a); + } + + if (j) + { + int b[n]; + g (b[1]); // { dg-warning "\\\[-Wmaybe-uninitialized" } + } +} diff --git a/gcc/tree-ssa-uninit.c b/gcc/tree-ssa-uninit.c index 0800f596ab1..f55ce1939ac 100644 --- a/gcc/tree-ssa-uninit.c +++ b/gcc/tree-ssa-uninit.c @@ -209,6 +209,16 @@ check_defs (ao_ref *ref, tree vdef, void *data_) { check_defs_data *data = (check_defs_data *)data_; gimple *def_stmt = SSA_NAME_DEF_STMT (vdef); + + /* The ASAN_MARK intrinsic doesn't modify the variable. */ + if (is_gimple_call (def_stmt) + && gimple_call_internal_p (def_stmt, IFN_ASAN_MARK)) + return false; + + /* End of VLA scope is not a kill. */ + if (gimple_call_builtin_p (def_stmt, BUILT_IN_STACK_RESTORE)) + return false; + /* If this is a clobber then if it is not a kill walk past it. */ if (gimple_clobber_p (def_stmt)) {