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efbf0136b4
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
30 lines
1.4 KiB
C++
30 lines
1.4 KiB
C++
// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wextra -std=c++11 -isystem %S/Inputs
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// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wnull-pointer-subtraction -std=c++11 -isystem %S/Inputs
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// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wextra -std=c++11 -isystem %S/Inputs -Wsystem-headers -DSYSTEM_WARNINGS
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// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic -Wnull-pointer-subtraction -std=c++11 -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 may have undefined behavior}}
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f = (char *)(f - (char *)0); // expected-warning {{performing pointer subtraction with a null pointer may have undefined behavior}}
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f = (char *)((char *)0 - (char *)0); // valid in C++
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if (1)
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f = (char *)((char *)0 - f); // expected-warning {{performing pointer subtraction with a null pointer may have undefined behavior}}
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else
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f = (char *)((char *)0 - f);
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if (0)
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f = (char *)((char *)0 - f);
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else
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f = (char *)((char *)0 - f); // expected-warning {{performing pointer subtraction with a null pointer may have 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 may have undefined behavior}}
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#endif
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}
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