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