thakis updated this revision to Diff 48373.
thakis marked an inline comment as done.
thakis added a comment.
address comments
http://reviews.llvm.org/D16552
Files:
include/clang/AST/DeclCXX.h
lib/AST/ASTImporter.cpp
lib/AST/DeclCXX.cpp
lib/Sema/SemaInit.cpp
lib/Serialization/ASTReaderDecl.cpp
lib/Serialization/ASTWriter.cpp
test/CXX/dcl.decl/dcl.fct.def/dcl.fct.def.default/p2.cpp
test/CXX/dcl.decl/dcl.init/p6.cpp
test/SemaCXX/attr-selectany.cpp
test/SemaCXX/constexpr-value-init.cpp
test/SemaCXX/cxx0x-cursory-default-delete.cpp
test/SemaCXX/illegal-member-initialization.cpp
Index: test/SemaCXX/illegal-member-initialization.cpp
===================================================================
--- test/SemaCXX/illegal-member-initialization.cpp
+++ test/SemaCXX/illegal-member-initialization.cpp
@@ -7,6 +7,7 @@
};
struct B {
+ int field;
};
struct X {
Index: test/SemaCXX/cxx0x-cursory-default-delete.cpp
===================================================================
--- test/SemaCXX/cxx0x-cursory-default-delete.cpp
+++ test/SemaCXX/cxx0x-cursory-default-delete.cpp
@@ -11,6 +11,7 @@
non_const_copy& operator = (non_const_copy&) &;
non_const_copy& operator = (non_const_copy&) &&;
non_const_copy() = default; // expected-note {{not viable}}
+ int uninit_field;
};
non_const_copy::non_const_copy(non_const_copy&) = default; // expected-note {{not viable}}
non_const_copy& non_const_copy::operator = (non_const_copy&) & = default; // expected-note {{not viable}}
@@ -30,6 +31,65 @@
ncc = cncc; // expected-error {{no viable overloaded}}
};
+struct no_fields { };
+struct all_init {
+ int a = 0;
+ int b = 0;
+};
+struct some_init {
+ int a = 0;
+ int b;
+ int c = 0;
+};
+struct some_init_mutable {
+ int a = 0;
+ mutable int b;
+ int c = 0;
+};
+struct some_init_def {
+ some_init_def() = default;
+ int a = 0;
+ int b;
+ int c = 0;
+};
+struct some_init_ctor {
+ some_init_ctor();
+ int a = 0;
+ int b;
+ int c = 0;
+};
+struct sub_some_init : public some_init_def { };
+struct sub_some_init_ctor : public some_init_def {
+ sub_some_init_ctor();
+};
+struct sub_some_init_ctor2 : public some_init_ctor {
+};
+struct some_init_container {
+ some_init_def sid;
+};
+struct some_init_container_ctor {
+ some_init_container_ctor();
+ some_init_def sid;
+};
+struct no_fields_container {
+ no_fields nf;
+};
+
+void constobjs() {
+ const no_fields nf; // ok
+ const all_init ai; // ok
+ const some_init si; // expected-error {{default initialization of an object of const type 'const some_init' without a user-provided default constructor}}
+ const some_init_mutable sim; // ok
+ const some_init_def sid; // expected-error {{default initialization of an object of const type 'const some_init_def' without a user-provided default constructor}}
+ const some_init_ctor sic; // ok
+ const sub_some_init ssi; // expected-error {{default initialization of an object of const type 'const sub_some_init' without a user-provided default constructor}}
+ const sub_some_init_ctor ssic; // ok
+ const sub_some_init_ctor2 ssic2; // ok
+ const some_init_container sicon; // expected-error {{default initialization of an object of const type 'const some_init_container' without a user-provided default constructor}}
+ const some_init_container_ctor siconc; // ok
+ const no_fields_container nfc; // ok
+}
+
struct non_const_derived : non_const_copy {
non_const_derived(const non_const_derived&) = default; // expected-error {{requires it to be non-const}}
non_const_derived& operator =(non_const_derived&) = default;
Index: test/SemaCXX/constexpr-value-init.cpp
===================================================================
--- test/SemaCXX/constexpr-value-init.cpp
+++ test/SemaCXX/constexpr-value-init.cpp
@@ -14,7 +14,7 @@
constexpr A a; // expected-error {{constant expression}} expected-note {{in call to 'A()'}}
}
-constexpr B b1; // expected-error {{without a user-provided default constructor}}
+constexpr B b1; // ok
constexpr B b2 = B(); // ok
static_assert(b2.a.a == 1, "");
static_assert(b2.a.b == 2, "");
Index: test/SemaCXX/attr-selectany.cpp
===================================================================
--- test/SemaCXX/attr-selectany.cpp
+++ test/SemaCXX/attr-selectany.cpp
@@ -39,7 +39,9 @@
// The D3D11 headers do something like this. MSVC doesn't error on this at
// all, even without the __declspec(selectany), in violation of the standard.
// We fall back to a warning for selectany to accept headers.
-struct SomeStruct {};
+struct SomeStruct {
+ int foo;
+};
extern const __declspec(selectany) SomeStruct some_struct; // expected-warning {{default initialization of an object of const type 'const SomeStruct' without a user-provided default constructor is a Microsoft extension}}
// It should be possible to redeclare variables that were defined
Index: test/CXX/dcl.decl/dcl.init/p6.cpp
===================================================================
--- test/CXX/dcl.decl/dcl.init/p6.cpp
+++ test/CXX/dcl.decl/dcl.init/p6.cpp
@@ -4,9 +4,9 @@
// 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.
+// user-provided default constructor, except if T has no uninitialized fields.
struct MakeNonPOD { MakeNonPOD(); };
-struct NoUserDefault : public MakeNonPOD { };
+struct NoUserDefault : public MakeNonPOD { int field; };
struct HasUserDefault { HasUserDefault(); };
void test_const_default_init() {
@@ -16,7 +16,7 @@
}
// rdar://8501008
-struct s0 {};
+struct s0 { int field; };
struct s1 { static const s0 foo; };
const struct s0 s1::foo; // expected-error{{default initialization of an object of const type 'const struct s0' without a user-provided default constructor}}
Index: test/CXX/dcl.decl/dcl.fct.def/dcl.fct.def.default/p2.cpp
===================================================================
--- test/CXX/dcl.decl/dcl.fct.def/dcl.fct.def.default/p2.cpp
+++ test/CXX/dcl.decl/dcl.fct.def/dcl.fct.def.default/p2.cpp
@@ -116,6 +116,7 @@
namespace PR13492 {
struct B {
B() = default;
+ int field;
};
void f() {
Index: lib/Serialization/ASTWriter.cpp
===================================================================
--- lib/Serialization/ASTWriter.cpp
+++ lib/Serialization/ASTWriter.cpp
@@ -5554,6 +5554,7 @@
Record.push_back(Data.DefaultedMoveAssignmentIsDeleted);
Record.push_back(Data.DefaultedDestructorIsDeleted);
Record.push_back(Data.HasTrivialSpecialMembers);
+ Record.push_back(Data.AllowConstDefaultInit);
Record.push_back(Data.DeclaredNonTrivialSpecialMembers);
Record.push_back(Data.HasIrrelevantDestructor);
Record.push_back(Data.HasConstexprNonCopyMoveConstructor);
Index: lib/Serialization/ASTReaderDecl.cpp
===================================================================
--- lib/Serialization/ASTReaderDecl.cpp
+++ lib/Serialization/ASTReaderDecl.cpp
@@ -1419,6 +1419,7 @@
Data.DefaultedMoveAssignmentIsDeleted = Record[Idx++];
Data.DefaultedDestructorIsDeleted = Record[Idx++];
Data.HasTrivialSpecialMembers = Record[Idx++];
+ Data.AllowConstDefaultInit = Record[Idx++];
Data.DeclaredNonTrivialSpecialMembers = Record[Idx++];
Data.HasIrrelevantDestructor = Record[Idx++];
Data.HasConstexprNonCopyMoveConstructor = Record[Idx++];
Index: lib/Sema/SemaInit.cpp
===================================================================
--- lib/Sema/SemaInit.cpp
+++ lib/Sema/SemaInit.cpp
@@ -3515,18 +3515,23 @@
// 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() &&
- !cast<CXXConstructorDecl>(Best->Function)->isUserProvided()) {
- if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
- Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
- return;
+ 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.
- CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Best->Function);
if (IsListInit && !Kind.AllowExplicit() && CtorDecl->isExplicit()) {
Sequence.SetFailed(InitializationSequence::FK_ExplicitConstructor);
return;
Index: lib/AST/DeclCXX.cpp
===================================================================
--- lib/AST/DeclCXX.cpp
+++ lib/AST/DeclCXX.cpp
@@ -59,6 +59,7 @@
DefaultedMoveAssignmentIsDeleted(false),
DefaultedDestructorIsDeleted(false),
HasTrivialSpecialMembers(SMF_All),
+ AllowConstDefaultInit(ACDI_Unknown),
DeclaredNonTrivialSpecialMembers(0),
HasIrrelevantDestructor(true),
HasConstexprNonCopyMoveConstructor(false),
@@ -392,6 +393,37 @@
return !forallBases([](const CXXRecordDecl *) { return true; });
}
+bool CXXRecordDecl::allowConstDefaultInitSlow() const {
+ assert(getDefinition() && "only call this on completed records");
+ if (hasUserProvidedDefaultConstructor()) {
+ data().setAllowConstDefInitKind(DefinitionData::ACDI_Yes);
+ return true;
+ }
+ for (const auto *F : fields()) {
+ if (F->hasInClassInitializer() || F->isMutable() || F->isUnnamedBitfield())
+ continue;
+ if (CXXRecordDecl *FieldType = F->getType()->getAsCXXRecordDecl()) {
+ if (!FieldType->allowConstDefaultInit()) {
+ data().setAllowConstDefInitKind(DefinitionData::ACDI_No);
+ return false;
+ }
+ } else {
+ data().setAllowConstDefInitKind(DefinitionData::ACDI_No);
+ return false;
+ }
+ }
+ for (const auto& BI : bases()) {
+ const RecordType *RT = BI.getType()->getAs<RecordType>();
+ CXXRecordDecl *Base = cast<CXXRecordDecl>(RT->getDecl());
+ if (!Base->allowConstDefaultInit()) {
+ data().setAllowConstDefInitKind(DefinitionData::ACDI_No);
+ return false;
+ }
+ }
+ data().setAllowConstDefInitKind(DefinitionData::ACDI_Yes);
+ return true;
+}
+
bool CXXRecordDecl::isTriviallyCopyable() const {
// C++0x [class]p5:
// A trivially copyable class is a class that:
Index: lib/AST/ASTImporter.cpp
===================================================================
--- lib/AST/ASTImporter.cpp
+++ lib/AST/ASTImporter.cpp
@@ -2035,6 +2035,7 @@
= FromData.DefaultedMoveAssignmentIsDeleted;
ToData.DefaultedDestructorIsDeleted = FromData.DefaultedDestructorIsDeleted;
ToData.HasTrivialSpecialMembers = FromData.HasTrivialSpecialMembers;
+ ToData.AllowConstDefaultInit = FromData.AllowConstDefaultInit;
ToData.HasIrrelevantDestructor = FromData.HasIrrelevantDestructor;
ToData.HasConstexprNonCopyMoveConstructor
= FromData.HasConstexprNonCopyMoveConstructor;
Index: include/clang/AST/DeclCXX.h
===================================================================
--- include/clang/AST/DeclCXX.h
+++ include/clang/AST/DeclCXX.h
@@ -402,6 +402,19 @@
/// which have been declared but not yet defined.
unsigned HasTrivialSpecialMembers : 6;
+ enum AllowConstDefInitKind {
+ ACDI_Unknown,
+ ACDI_Yes,
+ ACDI_No,
+ };
+ unsigned AllowConstDefaultInit : 2;
+ AllowConstDefInitKind allowConstDefInitKind() {
+ return static_cast<AllowConstDefInitKind>(AllowConstDefaultInit);
+ }
+ void setAllowConstDefInitKind(AllowConstDefInitKind Allow) {
+ AllowConstDefaultInit = Allow;
+ }
+
/// \brief The declared special members of this class which are known to be
/// non-trivial.
///
@@ -1270,6 +1283,15 @@
return !(data().HasTrivialSpecialMembers & SMF_Destructor);
}
+ /// \brief Determine whether declaring a const variable with this type is ok
+ /// per core issue 253.
+ bool allowConstDefaultInitSlow() const;
+ bool allowConstDefaultInit() const {
+ if (data().allowConstDefInitKind() != DefinitionData::ACDI_Unknown)
+ return data().allowConstDefInitKind() == DefinitionData::ACDI_Yes;
+ return allowConstDefaultInitSlow();
+ }
+
/// \brief Determine whether this class has a destructor which has no
/// semantic effect.
///
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