mirror of
https://github.com/llvm/llvm-project.git
synced 2025-04-26 23:16:06 +00:00
9cb00b9ecb
Summary: Test and produce warning for subtracting a pointer from null or subtracting null from a pointer. This reland adds the functionality that the warning is no longer reusing an existing warning, it has different wording for C vs C++ to refect the fact that nullptr-nullptr has defined behaviour in C++, it is suppressed when the warning is triggered by a system header and adds -Wnull-pointer-subtraction to allow the warning to be controlled. -Wextra implies -Wnull-pointer-subtraction. Author: Jamie Schmeiser <schmeise@ca.ibm.com> Reviewed By: efriedma (Eli Friedman), nickdesaulniers (Nick Desaulniers) Differential Revision: https://reviews.llvm.org/D98798
20 lines
1.0 KiB
C++
20 lines
1.0 KiB
C++
// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wextra -std=c++11 -isystem %S/Inputs
|
|
// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wnull-pointer-subtraction -std=c++11 -isystem %S/Inputs
|
|
// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wextra -std=c++11 -isystem %S/Inputs -Wsystem-headers -DSYSTEM_WARNINGS
|
|
// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wnull-pointer-subtraction -std=c++11 -isystem %S/Inputs -Wsystem-headers -DSYSTEM_WARNINGS
|
|
|
|
#include <pointer-subtraction.h>
|
|
|
|
void a() {
|
|
char *f = (char *)0;
|
|
f = (char *)((char *)0 - f); // expected-warning {{performing pointer subtraction with a null pointer may have undefined behavior}}
|
|
f = (char *)(f - (char *)0); // expected-warning {{performing pointer subtraction with a null pointer may have undefined behavior}}
|
|
f = (char *)((char *)0 - (char *)0); // valid in C++
|
|
|
|
#ifndef SYSTEM_WARNINGS
|
|
SYSTEM_MACRO(f);
|
|
#else
|
|
SYSTEM_MACRO(f); // expected-warning {{performing pointer subtraction with a null pointer may have undefined behavior}}
|
|
#endif
|
|
}
|