For C++11, do more checking of initializer lists up-front, enabling some subset of the final functionality. C just leaves the function early. C++98 runs through the same code path, but has no changed functionality either.
This is a first baby step towards supporting generalized initializer lists. This also removes an aggregate
test case that was just plain wrong, assuming that non-aggregates couldn't be initialized with initializer lists
in C++11 mode.
llvm-svn: 135177
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 835d837..d2122a4 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -7,9 +7,7 @@
//
//===----------------------------------------------------------------------===//
//
-// This file implements semantic analysis for initializers. The main entry
-// point is Sema::CheckInitList(), but all of the work is performed
-// within the InitListChecker class.
+// This file implements semantic analysis for initializers.
//
//===----------------------------------------------------------------------===//
@@ -712,7 +710,7 @@
} else if (SemaRef.getLangOptions().CPlusPlus) {
// C++ [dcl.init.aggr]p12:
// All implicit type conversions (clause 4) are considered when
- // initializing the aggregate member with an ini- tializer from
+ // initializing the aggregate member with an initializer from
// an initializer-list. If the initializer can initialize a
// member, the member is initialized. [...]
@@ -2384,52 +2382,10 @@
}
}
-/// \brief Attempt list initialization (C++0x [dcl.init.list])
-static void TryListInitialization(Sema &S,
- const InitializedEntity &Entity,
- const InitializationKind &Kind,
- InitListExpr *InitList,
- InitializationSequence &Sequence) {
- // FIXME: We only perform rudimentary checking of list
- // initializations at this point, then assume that any list
- // initialization of an array, aggregate, or scalar will be
- // well-formed. When we actually "perform" list initialization, we'll
- // do all of the necessary checking. C++0x initializer lists will
- // force us to perform more checking here.
-
- QualType DestType = Entity.getType();
-
- // C++ [dcl.init]p13:
- // If T is a scalar type, then a declaration of the form
- //
- // T x = { a };
- //
- // is equivalent to
- //
- // T x = a;
- if (DestType->isScalarType()) {
- if (InitList->getNumInits() > 1 && S.getLangOptions().CPlusPlus) {
- Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForScalar);
- return;
- }
-
- // Assume scalar initialization from a single value works.
- } else if (DestType->isAggregateType()) {
- // Assume aggregate initialization works.
- } else if (DestType->isVectorType()) {
- // Assume vector initialization works.
- } else if (DestType->isReferenceType()) {
- // FIXME: C++0x defines behavior for this.
- Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
- return;
- } else if (DestType->isRecordType()) {
- // FIXME: C++0x defines behavior for this
- Sequence.SetFailed(InitializationSequence::FK_InitListBadDestinationType);
- }
-
- // Add a general "list initialization" step.
- Sequence.AddListInitializationStep(DestType);
-}
+static void SelectInitialization(Sema &S, const InitializedEntity &Entity,
+ const InitializationKind &Kind,
+ Expr **Args, unsigned NumArgs,
+ InitializationSequence &Sequence);
/// \brief Try a reference initialization that involves calling a conversion
/// function.
@@ -3288,6 +3244,185 @@
<< src->getSourceRange();
}
+static bool hasDefaultConstructor(Sema &S, CXXRecordDecl *decl) {
+ DeclContext::lookup_const_iterator Con, ConEnd;
+ for (llvm::tie(Con, ConEnd) = S.LookupConstructors(decl);
+ Con != ConEnd; ++Con) {
+ // FIXME: A constructor template can be a default constructor, but we don't
+ // handle this in other places as well.
+ if (isa<FunctionTemplateDecl>(*Con))
+ continue;
+ CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(*Con);
+ if (Constructor->isDefaultConstructor())
+ return true;
+ }
+ return false;
+}
+
+/// \brief Attempt list initialization (C++0x [dcl.init.list])
+static void TryListInitialization(Sema &S,
+ const InitializedEntity &Entity,
+ const InitializationKind &Kind,
+ InitListExpr *InitList,
+ InitializationSequence &Sequence) {
+ QualType DestType = Entity.getType();
+
+ // If we're not in C++ mode, defer everything to the init list checker.
+ if (!S.getLangOptions().CPlusPlus) {
+ Sequence.AddListInitializationStep(DestType);
+ return;
+ }
+
+ // Early error return for some C++11 features when we're in 98 mode.
+ if (!S.getLangOptions().CPlusPlus0x) {
+ if (DestType->isReferenceType()) {
+ Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
+ return;
+ }
+ if (DestType->isRecordType() && !DestType->isAggregateType()) {
+ Sequence.SetFailed(InitializationSequence::FK_InitListBadDestinationType);
+ return;
+ }
+ }
+
+ // If we have a reference and not exactly one initializer (see below), unwrap
+ // the reference.
+ bool wasReference = false;
+ if (InitList->getNumInits() != 1) {
+ if (const ReferenceType *ref = DestType->getAs<ReferenceType>()) {
+ wasReference = true;
+ DestType = ref->getPointeeType();
+ }
+ }
+ // Create an object that automatically adds a ref binding step on successful
+ // return.
+ class AddRefBinding {
+ InitializationSequence &Sequence;
+ bool Bind;
+ QualType RefType;
+ public:
+ AddRefBinding(InitializationSequence &sequence, bool bind, QualType refType)
+ : Sequence(sequence), Bind(bind), RefType(refType) {}
+ ~AddRefBinding() {
+ if (Bind && Sequence) {
+ Sequence.AddReferenceBindingStep(RefType, /*temporary*/true);
+ }
+ }
+ } addRefBinding(Sequence, wasReference, Entity.getType());
+
+ // C++11 [dcl.init.list]p3:
+ // List-initialization of an object or reference of type T is defined as
+ // follows:
+ //
+ // - If the initializer list has no elements and T is a class type with
+ // a default constructor, the object is value-initialized.
+ //
+ // See DR990. This case is handled specially because if we let it get to
+ // overload resolution, std::initializer_list constructors would be chosen
+ // over the default constructor. When there's more than one initlist ctor,
+ // this would actually be ambiguous and fail.
+
+ const RecordType *recordType = DestType->getAs<RecordType>();
+ CXXRecordDecl *recordDecl = recordType ?
+ dyn_cast<CXXRecordDecl>(recordType->getDecl()) : 0;
+ if (recordDecl && InitList->getNumInits() == 0 &&
+ hasDefaultConstructor(S, recordDecl)) {
+ TryValueInitialization(S, Entity, Kind, Sequence);
+ return;
+ }
+
+ // - Otherwise, if T is an aggregate, aggregate initialization is
+ // performed.
+ //
+ // Aggregate initialization is the most complicated part. We delegate to
+ // an InitListChecker to build a representation of what's happening.
+ // We also treat vector types the same as aggregates.
+ if (DestType->isAggregateType() || DestType->isVectorType()) {
+ // FIXME: Deeper analysis necessary.
+ Sequence.AddListInitializationStep(DestType);
+ return;
+ }
+
+ // - Otherwise, if T is a specialization of std::initializer_list<E>, an
+ // initializer_list object is constructed as described below and used
+ // to initialize the object according to the rules for initialization
+ // of an object from a class of the same type.
+ //
+ // FIXME: Implement this case.
+
+ // - Otherwise, if T is a class type, constructors are considered. The
+ // applicable constructors are enumerated and the best one is chosen
+ // through overload resolution.
+ if (recordDecl) {
+ // FIXME: initializer_list constructors are applicable.
+ TryConstructorInitialization(S, Entity, Kind, InitList->getInits(),
+ InitList->getNumInits(), DestType, Sequence);
+ return;
+ }
+
+ // At this point, there is most likely a defect in the standard. The next
+ // bullet grabs all reference targets and creates temporaries from the init
+ // list. However, this means that code such as this doesn't work:
+ // int i;
+ // int &ri { i }; // error: non-const lvalue ref cannot bind to temporary.
+ // This is rather startling, since this code works:
+ // int &si ( i );
+ //
+ // DR934 (CD2 status) tried to address the problem by making the bullet about
+ // references be only about references to class types, letting references to
+ // other things fall through. This means the above works, but this still
+ // doesn't:
+ // string s;
+ // string &rs { s }; // cannot bind to temporary
+ // string &ss ( s ); // fine
+ // And this works, but has different semantics:
+ // const string &cs { s }; // binds to temporary copy
+ // const string &ds ( s ); // binds directly to s
+ // Also, the wording change from that DR somehow got lost in the FDIS.
+ //
+ // DR1095 (FDIS status) again discovered the problem, but didn't actually
+ // fix it.
+ //
+ // GCC implements it this way. We swap the next two bullets instead, thus
+ // always letting a reference bind to the single element of an initializer
+ // list, and constructing a temporary only if the isn't exactly one element.
+ // So in our order, the next bullet is:
+ //
+ // - Otherwise, if the initializer list has a single element, the object
+ // or reference is initialized from that element;
+ if (InitList->getNumInits() == 1) {
+ SelectInitialization(S, Entity, Kind, InitList->getInits(),
+ InitList->getNumInits(), Sequence);
+ // Adjust the type of the whole init list to be the same as that of the
+ // single initializer.
+ InitList->setType(InitList->getInits()[0]->getType());
+ return;
+ }
+
+ // - Otherwise, if T is a reference type, a prvalue temporary of the type
+ // referenced by T is list-initialized, and the reference is bound to
+ // that temporary.
+ //
+ // We implement this by unwrapping references at the start of the function
+ // and adding a reference binding step at the bottom.
+
+ // - Otherwise, if the initializer list has no elements, the object is
+ // value-initialized.
+ if (InitList->getNumInits() == 0) {
+ TryValueInitialization(S, Entity, Kind, Sequence);
+ return;
+ }
+
+ // - Otherwise, the program is ill-formed.
+ //
+ // The only way to get here ought to be for scalar types with > 1 inits.
+ assert(DestType->isScalarType() && "Something strange is list-initialized.");
+ assert(InitList->getNumInits() > 1 && "Strange number of initializers.");
+
+ Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForScalar);
+ return;
+}
+
/// \brief Determine whether we have compatible array types for the
/// purposes of GNU by-copy array initialization.
static bool hasCompatibleArrayTypes(ASTContext &Context,
@@ -3360,7 +3495,6 @@
Expr **Args,
unsigned NumArgs)
: FailedCandidateSet(Kind.getLocation()) {
- ASTContext &Context = S.Context;
// C++0x [dcl.init]p16:
// The semantics of initializers are as follows. The destination type is
@@ -3368,9 +3502,8 @@
// type is the type of the initializer expression. The source type is not
// defined when the initializer is a braced-init-list or when it is a
// parenthesized list of expressions.
- QualType DestType = Entity.getType();
- if (DestType->isDependentType() ||
+ if (Entity.getType()->isDependentType() ||
Expr::hasAnyTypeDependentArguments(Args, NumArgs)) {
SequenceKind = DependentSequence;
return;
@@ -3379,11 +3512,22 @@
// Almost everything is a normal sequence.
setSequenceKind(NormalSequence);
+ SelectInitialization(S, Entity, Kind, Args, NumArgs, *this);
+}
+
+static void SelectInitialization(Sema &S, const InitializedEntity &Entity,
+ const InitializationKind &Kind,
+ Expr **Args, unsigned NumArgs,
+ InitializationSequence &Sequence) {
+ ASTContext &Context = S.Context;
+ QualType DestType = Entity.getType();
+
for (unsigned I = 0; I != NumArgs; ++I)
if (Args[I]->getObjectKind() == OK_ObjCProperty) {
ExprResult Result = S.ConvertPropertyForRValue(Args[I]);
if (Result.isInvalid()) {
- SetFailed(FK_ConversionFromPropertyFailed);
+ Sequence.SetFailed(
+ InitializationSequence::FK_ConversionFromPropertyFailed);
return;
}
Args[I] = Result.take();
@@ -3400,7 +3544,7 @@
// - If the initializer is a braced-init-list, the object is
// list-initialized (8.5.4).
if (InitListExpr *InitList = dyn_cast_or_null<InitListExpr>(Initializer)) {
- TryListInitialization(S, Entity, Kind, InitList, *this);
+ TryListInitialization(S, Entity, Kind, InitList, Sequence);
return;
}
@@ -3412,22 +3556,22 @@
// by an object that can be converted into a T.
// (Therefore, multiple arguments are not permitted.)
if (NumArgs != 1)
- SetFailed(FK_TooManyInitsForReference);
+ Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForReference);
else
- TryReferenceInitialization(S, Entity, Kind, Args[0], *this);
+ TryReferenceInitialization(S, Entity, Kind, Args[0], Sequence);
return;
}
// - If the initializer is (), the object is value-initialized.
if (Kind.getKind() == InitializationKind::IK_Value ||
(Kind.getKind() == InitializationKind::IK_Direct && NumArgs == 0)) {
- TryValueInitialization(S, Entity, Kind, *this);
+ TryValueInitialization(S, Entity, Kind, Sequence);
return;
}
// Handle default initialization.
if (Kind.getKind() == InitializationKind::IK_Default) {
- TryDefaultInitialization(S, Entity, Kind, *this);
+ TryDefaultInitialization(S, Entity, Kind, Sequence);
return;
}
@@ -3438,7 +3582,7 @@
// ill-formed.
if (const ArrayType *DestAT = Context.getAsArrayType(DestType)) {
if (Initializer && IsStringInit(Initializer, DestAT, Context)) {
- TryStringLiteralInitialization(S, Entity, Kind, Initializer, *this);
+ TryStringLiteralInitialization(S, Entity, Kind, Initializer, Sequence);
return;
}
@@ -3451,16 +3595,17 @@
const ArrayType *SourceAT
= Context.getAsArrayType(Initializer->getType());
if (!hasCompatibleArrayTypes(S.Context, DestAT, SourceAT))
- SetFailed(FK_ArrayTypeMismatch);
+ Sequence.SetFailed(InitializationSequence::FK_ArrayTypeMismatch);
else if (Initializer->HasSideEffects(S.Context))
- SetFailed(FK_NonConstantArrayInit);
+ Sequence.SetFailed(InitializationSequence::FK_NonConstantArrayInit);
else {
- AddArrayInitStep(DestType);
+ Sequence.AddArrayInitStep(DestType);
}
} else if (DestAT->getElementType()->isAnyCharacterType())
- SetFailed(FK_ArrayNeedsInitListOrStringLiteral);
+ Sequence.SetFailed(
+ InitializationSequence::FK_ArrayNeedsInitListOrStringLiteral);
else
- SetFailed(FK_ArrayNeedsInitList);
+ Sequence.SetFailed(InitializationSequence::FK_ArrayNeedsInitList);
return;
}
@@ -3475,13 +3620,13 @@
if (!S.getLangOptions().CPlusPlus) {
// If allowed, check whether this is an Objective-C writeback conversion.
if (allowObjCWritebackConversion &&
- tryObjCWritebackConversion(S, *this, Entity, Initializer)) {
+ tryObjCWritebackConversion(S, Sequence, Entity, Initializer)) {
return;
}
// Handle initialization in C
- AddCAssignmentStep(DestType);
- MaybeProduceObjCObject(S, *this, Entity);
+ Sequence.AddCAssignmentStep(DestType);
+ MaybeProduceObjCObject(S, Sequence, Entity);
return;
}
@@ -3498,7 +3643,7 @@
(Context.hasSameUnqualifiedType(SourceType, DestType) ||
S.IsDerivedFrom(SourceType, DestType))))
TryConstructorInitialization(S, Entity, Kind, Args, NumArgs,
- Entity.getType(), *this);
+ Entity.getType(), Sequence);
// - Otherwise (i.e., for the remaining copy-initialization cases),
// user-defined conversion sequences that can convert from the source
// type to the destination type or (when a conversion function is
@@ -3506,12 +3651,12 @@
// 13.3.1.4, and the best one is chosen through overload resolution
// (13.3).
else
- TryUserDefinedConversion(S, Entity, Kind, Initializer, *this);
+ TryUserDefinedConversion(S, Entity, Kind, Initializer, Sequence);
return;
}
if (NumArgs > 1) {
- SetFailed(FK_TooManyInitsForScalar);
+ Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForScalar);
return;
}
assert(NumArgs == 1 && "Zero-argument case handled above");
@@ -3519,8 +3664,8 @@
// - Otherwise, if the source type is a (possibly cv-qualified) class
// type, conversion functions are considered.
if (!SourceType.isNull() && SourceType->isRecordType()) {
- TryUserDefinedConversion(S, Entity, Kind, Initializer, *this);
- MaybeProduceObjCObject(S, *this, Entity);
+ TryUserDefinedConversion(S, Entity, Kind, Initializer, Sequence);
+ MaybeProduceObjCObject(S, Sequence, Entity);
return;
}
@@ -3556,22 +3701,22 @@
LvalueICS.Standard.setAsIdentityConversion();
LvalueICS.Standard.setAllToTypes(ICS.Standard.getToType(0));
LvalueICS.Standard.First = ICS.Standard.First;
- AddConversionSequenceStep(LvalueICS, ICS.Standard.getToType(0));
+ Sequence.AddConversionSequenceStep(LvalueICS, ICS.Standard.getToType(0));
}
-
- AddPassByIndirectCopyRestoreStep(Entity.getType(), ShouldCopy);
+
+ Sequence.AddPassByIndirectCopyRestoreStep(Entity.getType(), ShouldCopy);
} else if (ICS.isBad()) {
DeclAccessPair dap;
if (Initializer->getType() == Context.OverloadTy &&
!S.ResolveAddressOfOverloadedFunction(Initializer
, DestType, false, dap))
- SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
+ Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
else
- SetFailed(InitializationSequence::FK_ConversionFailed);
+ Sequence.SetFailed(InitializationSequence::FK_ConversionFailed);
} else {
- AddConversionSequenceStep(ICS, Entity.getType());
+ Sequence.AddConversionSequenceStep(ICS, Entity.getType());
- MaybeProduceObjCObject(S, *this, Entity);
+ MaybeProduceObjCObject(S, Sequence, Entity);
}
}