[clang] 89b0972 - [Sema] Fix deleted function problem in implicitly movable test
Yang Fan via cfe-commits
cfe-commits at lists.llvm.org
Thu Dec 31 23:48:05 PST 2020
Author: Yang Fan
Date: 2021-01-01T15:47:49+08:00
New Revision: 89b0972aa2f58f927633c63570b36550a17f4e63
URL: https://github.com/llvm/llvm-project/commit/89b0972aa2f58f927633c63570b36550a17f4e63
DIFF: https://github.com/llvm/llvm-project/commit/89b0972aa2f58f927633c63570b36550a17f4e63.diff
LOG: [Sema] Fix deleted function problem in implicitly movable test
In implicitly movable test, a two-stage overload resolution is performed.
If the first overload resolution selects a deleted function, Clang directly
performs the second overload resolution, without checking whether the
deleted function matches the additional criteria.
This patch fixes the above problem.
Reviewed By: Quuxplusone
Differential Revision: https://reviews.llvm.org/D92936
Added:
clang/test/CXX/class/class.init/class.copy.elision/p3.cpp
Modified:
clang/lib/Sema/SemaInit.cpp
clang/lib/Sema/SemaStmt.cpp
Removed:
################################################################################
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 6d2e6094e79c..4a965c60c74e 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -4119,7 +4119,9 @@ static void TryConstructorInitialization(Sema &S,
InitializationSequence::FK_ListConstructorOverloadFailed :
InitializationSequence::FK_ConstructorOverloadFailed,
Result);
- return;
+
+ if (Result != OR_Deleted)
+ return;
}
bool HadMultipleCandidates = (CandidateSet.size() > 1);
@@ -4140,31 +4142,45 @@ static void TryConstructorInitialization(Sema &S,
return;
}
- // C++11 [dcl.init]p6:
- // If a program calls for the default initialization of an object
- // of a const-qualified type T, T shall be a class type with a
- // user-provided default constructor.
- // C++ core issue 253 proposal:
- // If the implicit default constructor initializes all subobjects, no
- // initializer should be required.
- // The 253 proposal is for example needed to process libstdc++ headers in 5.x.
CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
- if (Kind.getKind() == InitializationKind::IK_Default &&
- Entity.getType().isConstQualified()) {
- if (!CtorDecl->getParent()->allowConstDefaultInit()) {
- if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
- Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
+ if (Result != OR_Deleted) { // TODO: Support for more than one failure.
+ // C++11 [dcl.init]p6:
+ // If a program calls for the default initialization of an object
+ // of a const-qualified type T, T shall be a class type with a
+ // user-provided default constructor.
+ // C++ core issue 253 proposal:
+ // If the implicit default constructor initializes all subobjects, no
+ // initializer should be required.
+ // The 253 proposal is for example needed to process libstdc++ headers
+ // in 5.x.
+ if (Kind.getKind() == InitializationKind::IK_Default &&
+ Entity.getType().isConstQualified()) {
+ if (!CtorDecl->getParent()->allowConstDefaultInit()) {
+ if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
+ Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
+ return;
+ }
+ }
+
+ // C++11 [over.match.list]p1:
+ // In copy-list-initialization, if an explicit constructor is chosen, the
+ // initializer is ill-formed.
+ if (IsListInit && !Kind.AllowExplicit() && CtorDecl->isExplicit()) {
+ Sequence.SetFailed(InitializationSequence::FK_ExplicitConstructor);
return;
}
}
- // C++11 [over.match.list]p1:
- // In copy-list-initialization, if an explicit constructor is chosen, the
- // initializer is ill-formed.
- if (IsListInit && !Kind.AllowExplicit() && CtorDecl->isExplicit()) {
- Sequence.SetFailed(InitializationSequence::FK_ExplicitConstructor);
+ // [class.copy.elision]p3:
+ // In some copy-initialization contexts, a two-stage overload resolution
+ // is performed.
+ // If the first overload resolution selects a deleted function, we also
+ // need the initialization sequence to decide whether to perform the second
+ // overload resolution.
+ // For deleted functions in other contexts, there is no need to get the
+ // initialization sequence.
+ if (Result == OR_Deleted && Kind.getKind() != InitializationKind::IK_Copy)
return;
- }
// Add the constructor initialization step. Any cv-qualification conversion is
// subsumed by the initialization.
@@ -5260,7 +5276,16 @@ static void TryUserDefinedConversion(Sema &S,
Sequence.SetOverloadFailure(
InitializationSequence::FK_UserConversionOverloadFailed,
Result);
- return;
+
+ // [class.copy.elision]p3:
+ // In some copy-initialization contexts, a two-stage overload resolution
+ // is performed.
+ // If the first overload resolution selects a deleted function, we also
+ // need the initialization sequence to decide whether to perform the second
+ // overload resolution.
+ if (!(Result == OR_Deleted &&
+ Kind.getKind() == InitializationKind::IK_Copy))
+ return;
}
FunctionDecl *Function = Best->Function;
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 8d0ebe7e2409..3318fda07175 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -3118,11 +3118,14 @@ bool Sema::isCopyElisionCandidate(QualType ReturnType, const VarDecl *VD,
/// If move-initialization is not possible, such that we must fall back to
/// treating the operand as an lvalue, we will leave Res in its original
/// invalid state.
-static void TryMoveInitialization(Sema& S,
- const InitializedEntity &Entity,
+///
+/// \returns Whether we need to do the second overload resolution. If the first
+/// overload resolution fails, or if the first overload resolution succeeds but
+/// the selected constructor/operator doesn't match the additional criteria, we
+/// need to do the second overload resolution.
+static bool TryMoveInitialization(Sema &S, const InitializedEntity &Entity,
const VarDecl *NRVOCandidate,
- QualType ResultType,
- Expr *&Value,
+ QualType ResultType, Expr *&Value,
bool ConvertingConstructorsOnly,
ExprResult &Res) {
ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, Value->getType(),
@@ -3135,8 +3138,10 @@ static void TryMoveInitialization(Sema& S,
InitializationSequence Seq(S, Entity, Kind, InitExpr);
- if (!Seq)
- return;
+ bool NeedSecondOverloadResolution = true;
+ if (!Seq && Seq.getFailedOverloadResult() != OR_Deleted) {
+ return NeedSecondOverloadResolution;
+ }
for (const InitializationSequence::Step &Step : Seq.steps()) {
if (Step.Kind != InitializationSequence::SK_ConstructorInitialization &&
@@ -3179,6 +3184,7 @@ static void TryMoveInitialization(Sema& S,
}
}
+ NeedSecondOverloadResolution = false;
// Promote "AsRvalue" to the heap, since we now need this
// expression node to persist.
Value =
@@ -3189,6 +3195,8 @@ static void TryMoveInitialization(Sema& S,
// using the constructor we found.
Res = Seq.Perform(S, Entity, Kind, Value);
}
+
+ return NeedSecondOverloadResolution;
}
/// Perform the initialization of a potentially-movable value, which
@@ -3213,6 +3221,7 @@ Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
// select the constructor for the copy is first performed as if the object
// were designated by an rvalue.
ExprResult Res = ExprError();
+ bool NeedSecondOverloadResolution = true;
if (AllowNRVO) {
bool AffectedByCWG1579 = false;
@@ -3229,11 +3238,11 @@ Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
}
if (NRVOCandidate) {
- TryMoveInitialization(*this, Entity, NRVOCandidate, ResultType, Value,
- true, Res);
+ NeedSecondOverloadResolution = TryMoveInitialization(
+ *this, Entity, NRVOCandidate, ResultType, Value, true, Res);
}
- if (!Res.isInvalid() && AffectedByCWG1579) {
+ if (!NeedSecondOverloadResolution && AffectedByCWG1579) {
QualType QT = NRVOCandidate->getType();
if (QT.getNonReferenceType()
.getUnqualifiedType()
@@ -3256,7 +3265,7 @@ Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
Diag(Value->getExprLoc(), diag::note_add_std_move_in_cxx11)
<< FixItHint::CreateReplacement(Value->getSourceRange(), Str);
}
- } else if (Res.isInvalid() &&
+ } else if (NeedSecondOverloadResolution &&
!getDiagnostics().isIgnored(diag::warn_return_std_move,
Value->getExprLoc())) {
const VarDecl *FakeNRVOCandidate =
@@ -3297,7 +3306,7 @@ Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
// Either we didn't meet the criteria for treating an lvalue as an rvalue,
// above, or overload resolution failed. Either way, we need to try
// (again) now with the return value expression as written.
- if (Res.isInvalid())
+ if (NeedSecondOverloadResolution)
Res = PerformCopyInitialization(Entity, SourceLocation(), Value);
return Res;
diff --git a/clang/test/CXX/class/class.init/class.copy.elision/p3.cpp b/clang/test/CXX/class/class.init/class.copy.elision/p3.cpp
new file mode 100644
index 000000000000..b3427243bd61
--- /dev/null
+++ b/clang/test/CXX/class/class.init/class.copy.elision/p3.cpp
@@ -0,0 +1,50 @@
+// RUN: %clang_cc1 -std=c++20 -fsyntax-only -fcxx-exceptions -verify=expected %s
+// RUN: %clang_cc1 -std=c++17 -fsyntax-only -fcxx-exceptions -verify=expected %s
+// RUN: %clang_cc1 -std=c++14 -fsyntax-only -fcxx-exceptions -verify=expected %s
+// RUN: %clang_cc1 -std=c++11 -fsyntax-only -fcxx-exceptions -verify=expected %s
+
+namespace test_delete_function {
+struct A1 {
+ A1();
+ A1(const A1 &);
+ A1(A1 &&) = delete; // expected-note {{'A1' has been explicitly marked deleted here}}
+};
+A1 test1() {
+ A1 a;
+ return a; // expected-error {{call to deleted constructor of 'test_delete_function::A1'}}
+}
+
+struct A2 {
+ A2();
+ A2(const A2 &);
+
+private:
+ A2(A2 &&); // expected-note {{declared private here}}
+};
+A2 test2() {
+ A2 a;
+ return a; // expected-error {{calling a private constructor of class 'test_delete_function::A2'}}
+}
+
+struct C {};
+
+struct B1 {
+ B1(C &);
+ B1(C &&) = delete; // expected-note {{'B1' has been explicitly marked deleted here}}
+};
+B1 test3() {
+ C c;
+ return c; // expected-error {{conversion function from 'test_delete_function::C' to 'test_delete_function::B1' invokes a deleted function}}
+}
+
+struct B2 {
+ B2(C &);
+
+private:
+ B2(C &&); // expected-note {{declared private here}}
+};
+B2 test4() {
+ C c;
+ return c; // expected-error {{calling a private constructor of class 'test_delete_function::B2'}}
+}
+} // namespace test_delete_function
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