malcolm.parsons created this revision.
Herald added subscribers: xazax.hun, JDevlieghere.
Do not replace the constructor or destructor of a union with =default
if it would be implicitly deleted.
Fixes: PR27926
https://reviews.llvm.org/D38179
Files:
clang-tidy/modernize/UseEqualsDefaultCheck.cpp
test/clang-tidy/modernize-use-equals-default.cpp
Index: test/clang-tidy/modernize-use-equals-default.cpp
===================================================================
--- test/clang-tidy/modernize-use-equals-default.cpp
+++ test/clang-tidy/modernize-use-equals-default.cpp
@@ -205,3 +205,23 @@
};
STRUCT_WITH_DEFAULT(unsigned char, InMacro)
+
+// Unions
+union UnionOfPOD {
+ UnionOfPOD() {}
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use '= default'
+ // CHECK-FIXES: UnionOfPOD() = default;
+ ~UnionOfPOD() {}
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use '= default'
+ // CHECK-FIXES: ~UnionOfPOD() = default;
+ int i;
+ double j;
+};
+
+union UnionOfNonTrivial {
+ UnionOfNonTrivial() {}
+ ~UnionOfNonTrivial() {}
+ int i;
+ double j;
+ NE k;
+};
Index: clang-tidy/modernize/UseEqualsDefaultCheck.cpp
===================================================================
--- clang-tidy/modernize/UseEqualsDefaultCheck.cpp
+++ clang-tidy/modernize/UseEqualsDefaultCheck.cpp
@@ -111,6 +111,44 @@
BasesToInit.size() + FieldsToInit.size();
}
+/// Checks that the given default constructor can be defaulted.
+static bool defaultConstructorCanBeDefaulted(ASTContext *Context,
+ const CXXMethodDecl *Operator) {
+ const auto *Record = Operator->getParent();
+
+ // A defaulted default constructor of a union with a field with a non trivial
+ // default constructor would be deleted.
+ if (Record->isUnion()) {
+ auto FieldsToInit = getAllNamedFields(Record);
+
+ for (const auto *Field : FieldsToInit) {
+ QualType T = Context->getBaseElementType(Field->getType());
+
+ if (const RecordType *RecordTy = T->getAs<RecordType>()) {
+ CXXRecordDecl *FieldRec = cast<CXXRecordDecl>(RecordTy->getDecl());
+
+ if (FieldRec->hasNonTrivialDefaultConstructor())
+ return false;
+ }
+ }
+ }
+
+ return true;
+}
+
+/// Checks that the given destructor can be defaulted.
+static bool destructorCanBeDefaulted(ASTContext *Context,
+ const CXXMethodDecl *Operator) {
+ const auto *Record = Operator->getParent();
+
+ // A defaulted destructor of a union with a field with a non trivial
+ // destructor would be deleted.
+ if (Record->defaultedDestructorIsDeleted())
+ return false;
+
+ return true;
+}
+
/// \brief Checks that the given method is an overloading of the assignment
/// operator, has copy signature, returns a reference to "*this" and copies
/// all its members and subobjects.
@@ -274,6 +312,8 @@
if (const auto *Ctor = dyn_cast<CXXConstructorDecl>(SpecialFunctionDecl)) {
if (Ctor->getNumParams() == 0) {
+ if (!defaultConstructorCanBeDefaulted(Result.Context, Ctor))
+ return;
SpecialFunctionName = "default constructor";
} else {
if (!isCopyConstructorAndCanBeDefaulted(Result.Context, Ctor))
@@ -286,6 +326,8 @@
}
}
} else if (isa<CXXDestructorDecl>(SpecialFunctionDecl)) {
+ if (!destructorCanBeDefaulted(Result.Context, SpecialFunctionDecl))
+ return;
SpecialFunctionName = "destructor";
} else {
if (!isCopyAssignmentAndCanBeDefaulted(Result.Context,
SpecialFunctionDecl))
Index: test/clang-tidy/modernize-use-equals-default.cpp
===================================================================
--- test/clang-tidy/modernize-use-equals-default.cpp
+++ test/clang-tidy/modernize-use-equals-default.cpp
@@ -205,3 +205,23 @@
};
STRUCT_WITH_DEFAULT(unsigned char, InMacro)
+
+// Unions
+union UnionOfPOD {
+ UnionOfPOD() {}
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use '= default'
+ // CHECK-FIXES: UnionOfPOD() = default;
+ ~UnionOfPOD() {}
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use '= default'
+ // CHECK-FIXES: ~UnionOfPOD() = default;
+ int i;
+ double j;
+};
+
+union UnionOfNonTrivial {
+ UnionOfNonTrivial() {}
+ ~UnionOfNonTrivial() {}
+ int i;
+ double j;
+ NE k;
+};
Index: clang-tidy/modernize/UseEqualsDefaultCheck.cpp
===================================================================
--- clang-tidy/modernize/UseEqualsDefaultCheck.cpp
+++ clang-tidy/modernize/UseEqualsDefaultCheck.cpp
@@ -111,6 +111,44 @@
BasesToInit.size() + FieldsToInit.size();
}
+/// Checks that the given default constructor can be defaulted.
+static bool defaultConstructorCanBeDefaulted(ASTContext *Context,
+ const CXXMethodDecl *Operator) {
+ const auto *Record = Operator->getParent();
+
+ // A defaulted default constructor of a union with a field with a non trivial
+ // default constructor would be deleted.
+ if (Record->isUnion()) {
+ auto FieldsToInit = getAllNamedFields(Record);
+
+ for (const auto *Field : FieldsToInit) {
+ QualType T = Context->getBaseElementType(Field->getType());
+
+ if (const RecordType *RecordTy = T->getAs<RecordType>()) {
+ CXXRecordDecl *FieldRec = cast<CXXRecordDecl>(RecordTy->getDecl());
+
+ if (FieldRec->hasNonTrivialDefaultConstructor())
+ return false;
+ }
+ }
+ }
+
+ return true;
+}
+
+/// Checks that the given destructor can be defaulted.
+static bool destructorCanBeDefaulted(ASTContext *Context,
+ const CXXMethodDecl *Operator) {
+ const auto *Record = Operator->getParent();
+
+ // A defaulted destructor of a union with a field with a non trivial
+ // destructor would be deleted.
+ if (Record->defaultedDestructorIsDeleted())
+ return false;
+
+ return true;
+}
+
/// \brief Checks that the given method is an overloading of the assignment
/// operator, has copy signature, returns a reference to "*this" and copies
/// all its members and subobjects.
@@ -274,6 +312,8 @@
if (const auto *Ctor = dyn_cast<CXXConstructorDecl>(SpecialFunctionDecl)) {
if (Ctor->getNumParams() == 0) {
+ if (!defaultConstructorCanBeDefaulted(Result.Context, Ctor))
+ return;
SpecialFunctionName = "default constructor";
} else {
if (!isCopyConstructorAndCanBeDefaulted(Result.Context, Ctor))
@@ -286,6 +326,8 @@
}
}
} else if (isa<CXXDestructorDecl>(SpecialFunctionDecl)) {
+ if (!destructorCanBeDefaulted(Result.Context, SpecialFunctionDecl))
+ return;
SpecialFunctionName = "destructor";
} else {
if (!isCopyAssignmentAndCanBeDefaulted(Result.Context, SpecialFunctionDecl))
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