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From: "msebor at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/95515] New: missing --Wnonnull on a straightforward call with a null pointer Date: Wed, 03 Jun 2020 20:11:28 +0000 [thread overview] Message-ID: <bug-95515-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95515 Bug ID: 95515 Summary: missing --Wnonnull on a straightforward call with a null pointer Product: gcc Version: 10.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: middle-end Assignee: unassigned at gcc dot gnu.org Reporter: msebor at gcc dot gnu.org Target Milestone: --- In the following test case only the first two instances of passing a null argument to a nonnull function are diagnosed. The third one isn't. $ cat z.c && gcc -O2 -S -Wall -Wpedantic -fdump-tree-optimized=/dev/stdout z.c __attribute__ ((nonnull)) void f (void*); void f1 (void) { f (0); // Wnonnull (good) } void f2 (void) { void *const p = 0; f (p); // -Wnonnull (good) } void f3 (void) { void *p = 0; f (p); // missing -Wnonnull } z.c: In function ‘f1’: z.c:5:3: warning: null argument where non-null required (argument 1) [-Wnonnull] 5 | f (0); // Wnonnull (good) | ^ z.c: In function ‘f2’: z.c:11:3: warning: null argument where non-null required (argument 1) [-Wnonnull] 11 | f (p); // -Wnonnull (good) | ^ ;; Function f1 (f1, funcdef_no=0, decl_uid=1932, cgraph_uid=1, symbol_order=0) f1 () { <bb 2> [local count: 1073741824]: f (0B); [tail call] return; } ;; Function f2 (f2, funcdef_no=4, decl_uid=1935, cgraph_uid=2, symbol_order=1) f2 () { <bb 2> [local count: 1073741824]: f (0B); [tail call] return; } ;; Function f3 (f3, funcdef_no=6, decl_uid=1939, cgraph_uid=3, symbol_order=2) f3 () { <bb 2> [local count: 1073741824]: f (0B); [tail call] return; } Clang is similarly ineffective on its own, but its analyzer detects all three: $ clang -O2 -S -Wall --analyze z.c z.c:5:3: warning: Null pointer passed as an argument to a 'nonnull' parameter f (0); // Wnonnull (good) ^~~~~ z.c:11:3: warning: Null pointer passed as an argument to a 'nonnull' parameter f (p); // -Wnonnull (good) ^~~~~ z.c:18:3: warning: Null pointer passed as an argument to a 'nonnull' parameter f (p); // missing -Wnonnull ^~~~~ 3 warnings generated.
next reply other threads:[~2020-06-03 20:11 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-06-03 20:11 msebor at gcc dot gnu.org [this message] 2023-02-02 22:26 ` [Bug middle-end/95515] " pinskia at gcc dot gnu.org 2023-02-02 22:39 ` pinskia at gcc dot gnu.org
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