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The zero-as-null-pointer-constant check should not fire if it is inside
a defaulted function, e.g. defaulted spaceship operators.
Add C++20 tests with spaceship operators.
Fixes #50221
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D138727
Files:
clang/lib/Sema/Sema.cpp
clang/test/SemaCXX/warn-zero-nullptr-cxx20.cpp
Index: clang/test/SemaCXX/warn-zero-nullptr-cxx20.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/warn-zero-nullptr-cxx20.cpp
@@ -0,0 +1,53 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s -isystem %S/Inputs
-Wzero-as-null-pointer-constant -std=c++20
+
+#include <warn-zero-nullptr.h>
+
+namespace std {
+class strong_ordering;
+
+// Mock how STD defined unspecified parameters for the operators below.
+struct _CmpUnspecifiedParam {
+ consteval
+ _CmpUnspecifiedParam(int _CmpUnspecifiedParam::*) noexcept {}
+};
+
+struct strong_ordering {
+ signed char value;
+
+ friend constexpr bool operator==(strong_ordering v,
+ _CmpUnspecifiedParam) noexcept {
+ return v.value == 0;
+ }
+ friend constexpr bool operator<(strong_ordering v,
+ _CmpUnspecifiedParam) noexcept {
+ return v.value < 0;
+ }
+ friend constexpr bool operator>(strong_ordering v,
+ _CmpUnspecifiedParam) noexcept {
+ return v.value > 0;
+ }
+ friend constexpr bool operator>=(strong_ordering v,
+ _CmpUnspecifiedParam) noexcept {
+ return v.value >= 0;
+ }
+ static const strong_ordering equal, greater, less;
+};
+constexpr strong_ordering strong_ordering::equal = {0};
+constexpr strong_ordering strong_ordering::greater = {1};
+constexpr strong_ordering strong_ordering::less = {-1};
+} // namespace std
+
+struct A {
+ int a;
+ constexpr auto operator<=>(const A &other) const = default;
+};
+
+void test_cxx_rewritten_binary_ops() {
+ A a1, a2;
+ bool result;
+ result = (a1 < a2);
+ result = (a1 >= a2);
+ int *ptr = 0; // expected-warning{{zero as null pointer constant}}
+ result = (a1 > (ptr == 0 ? a1 : a2)); // expected-warning{{zero as null
pointer constant}}
+ result = (a1 > ((a1 > (ptr == 0 ? a1 : a2)) ? a1 : a2)); //
expected-warning{{zero as null pointer constant}}
+}
Index: clang/lib/Sema/Sema.cpp
===================================================================
--- clang/lib/Sema/Sema.cpp
+++ clang/lib/Sema/Sema.cpp
@@ -597,6 +597,13 @@
CodeSynthesisContext::RewritingOperatorAsSpaceship)
return;
+ // Ignore null pointers in defaulted functions, e.g. defaulted comparison
+ // operators.
+ FunctionDecl *FD = getCurFunctionDecl();
+ if (FD && FD->isDefaulted()) {
+ return;
+ }
+
// If it is a macro from system header, and if the macro name is not "NULL",
// do not warn.
SourceLocation MaybeMacroLoc = E->getBeginLoc();
Index: clang/test/SemaCXX/warn-zero-nullptr-cxx20.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/warn-zero-nullptr-cxx20.cpp
@@ -0,0 +1,53 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s -isystem %S/Inputs -Wzero-as-null-pointer-constant -std=c++20
+
+#include <warn-zero-nullptr.h>
+
+namespace std {
+class strong_ordering;
+
+// Mock how STD defined unspecified parameters for the operators below.
+struct _CmpUnspecifiedParam {
+ consteval
+ _CmpUnspecifiedParam(int _CmpUnspecifiedParam::*) noexcept {}
+};
+
+struct strong_ordering {
+ signed char value;
+
+ friend constexpr bool operator==(strong_ordering v,
+ _CmpUnspecifiedParam) noexcept {
+ return v.value == 0;
+ }
+ friend constexpr bool operator<(strong_ordering v,
+ _CmpUnspecifiedParam) noexcept {
+ return v.value < 0;
+ }
+ friend constexpr bool operator>(strong_ordering v,
+ _CmpUnspecifiedParam) noexcept {
+ return v.value > 0;
+ }
+ friend constexpr bool operator>=(strong_ordering v,
+ _CmpUnspecifiedParam) noexcept {
+ return v.value >= 0;
+ }
+ static const strong_ordering equal, greater, less;
+};
+constexpr strong_ordering strong_ordering::equal = {0};
+constexpr strong_ordering strong_ordering::greater = {1};
+constexpr strong_ordering strong_ordering::less = {-1};
+} // namespace std
+
+struct A {
+ int a;
+ constexpr auto operator<=>(const A &other) const = default;
+};
+
+void test_cxx_rewritten_binary_ops() {
+ A a1, a2;
+ bool result;
+ result = (a1 < a2);
+ result = (a1 >= a2);
+ int *ptr = 0; // expected-warning{{zero as null pointer constant}}
+ result = (a1 > (ptr == 0 ? a1 : a2)); // expected-warning{{zero as null pointer constant}}
+ result = (a1 > ((a1 > (ptr == 0 ? a1 : a2)) ? a1 : a2)); // expected-warning{{zero as null pointer constant}}
+}
Index: clang/lib/Sema/Sema.cpp
===================================================================
--- clang/lib/Sema/Sema.cpp
+++ clang/lib/Sema/Sema.cpp
@@ -597,6 +597,13 @@
CodeSynthesisContext::RewritingOperatorAsSpaceship)
return;
+ // Ignore null pointers in defaulted functions, e.g. defaulted comparison
+ // operators.
+ FunctionDecl *FD = getCurFunctionDecl();
+ if (FD && FD->isDefaulted()) {
+ return;
+ }
+
// If it is a macro from system header, and if the macro name is not "NULL",
// do not warn.
SourceLocation MaybeMacroLoc = E->getBeginLoc();
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