llvm-project/clang/test/Sema/pointer-subtraction.c
Jamie Schmeiser efbf0136b4 Only issue warning for subtraction involving null pointers on live code paths
Summary:
Change the warning produced for subtraction from (or with) a null pointer
to only be produced when the code path is live.
https://github.com/llvm/llvm-project/issues/54570

Author: Jamie Schmeiser <schmeise@ca.ibm.com>
Reviewed By: anarazel (Andres Freund)
Differential Revision: https://reviews.llvm.org/D126816
2022-06-03 10:10:37 -04:00

30 lines
1.6 KiB
C

// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wextra -std=c11 -isystem %S/Inputs
// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wnull-pointer-subtraction -std=c11 -isystem %S/Inputs
// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wextra -std=c11 -isystem %S/Inputs -Wsystem-headers -DSYSTEM_WARNINGS
// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wnull-pointer-subtraction -std=c11 -isystem %S/Inputs -Wsystem-headers -DSYSTEM_WARNINGS
#include <pointer-subtraction.h>
void a(void) {
char *f = (char *)0;
f = (char *)((char *)0 - f); // expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}}
f = (char *)(f - (char *)0); // expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}}
f = (char *)((char *)0 - (char *)0); // expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}} expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}}
if (1)
f = (char *)((char *)0 - f); // expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}}
else
f = (char *)((char *)0 - f);
if (0)
f = (char *)((char *)0 - f);
else
f = (char *)((char *)0 - f); // expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}}
#ifndef SYSTEM_WARNINGS
SYSTEM_MACRO(f);
#else
SYSTEM_MACRO(f); // expected-warning {{performing pointer subtraction with a null pointer has undefined behavior}}
#endif
}