C++ DR1611, 1658, 2180: implement "potentially constructed subobject" rules for special member functions.
Essentially, as a base class constructor does not construct virtual bases, such
a constructor for an abstract class does not need the corresponding base class
construction to be valid, and likewise for destructors.
This creates an awkward situation: clang will sometimes generate references to
the complete object and deleting destructors for an abstract class (it puts
them in the construction vtable for a derived class). But we can't generate a
"correct" version of these because we can't generate references to base class
constructors any more (if they're template specializations, say, we might not
have instantiated them and can't assume any other TU will emit a copy).
Fortunately, we don't need to, since no correct program can ever invoke them,
so instead emit symbols that just trap.
We should stop emitting references to these symbols, but still need to emit
definitions for compatibility.
llvm-svn: 296275
diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp
index 3846ace..7418370 100644
--- a/clang/lib/AST/DeclCXX.cpp
+++ b/clang/lib/AST/DeclCXX.cpp
@@ -68,7 +68,8 @@
HasConstexprDefaultConstructor(false),
HasNonLiteralTypeFieldsOrBases(false), ComputedVisibleConversions(false),
UserProvidedDefaultConstructor(false), DeclaredSpecialMembers(0),
- ImplicitCopyConstructorHasConstParam(true),
+ ImplicitCopyConstructorCanHaveConstParamForVBase(true),
+ ImplicitCopyConstructorCanHaveConstParamForNonVBase(true),
ImplicitCopyAssignmentHasConstParam(true),
HasDeclaredCopyConstructorWithConstParam(false),
HasDeclaredCopyAssignmentWithConstParam(false), IsLambda(false),
@@ -227,7 +228,7 @@
// 'const B&' or 'const volatile B&' [...]
if (CXXRecordDecl *VBaseDecl = VBase.getType()->getAsCXXRecordDecl())
if (!VBaseDecl->hasCopyConstructorWithConstParam())
- data().ImplicitCopyConstructorHasConstParam = false;
+ data().ImplicitCopyConstructorCanHaveConstParamForVBase = false;
// C++1z [dcl.init.agg]p1:
// An aggregate is a class with [...] no virtual base classes
@@ -264,6 +265,14 @@
// In the definition of a constexpr constructor [...]
// -- the class shall not have any virtual base classes
data().DefaultedDefaultConstructorIsConstexpr = false;
+
+ // C++1z [class.copy]p8:
+ // The implicitly-declared copy constructor for a class X will have
+ // the form 'X::X(const X&)' if each potentially constructed subobject
+ // has a copy constructor whose first parameter is of type
+ // 'const B&' or 'const volatile B&' [...]
+ if (!BaseClassDecl->hasCopyConstructorWithConstParam())
+ data().ImplicitCopyConstructorCanHaveConstParamForVBase = false;
} else {
// C++ [class.ctor]p5:
// A default constructor is trivial [...] if:
@@ -306,6 +315,14 @@
// default constructor is constexpr.
if (!BaseClassDecl->hasConstexprDefaultConstructor())
data().DefaultedDefaultConstructorIsConstexpr = false;
+
+ // C++1z [class.copy]p8:
+ // The implicitly-declared copy constructor for a class X will have
+ // the form 'X::X(const X&)' if each potentially constructed subobject
+ // has a copy constructor whose first parameter is of type
+ // 'const B&' or 'const volatile B&' [...]
+ if (!BaseClassDecl->hasCopyConstructorWithConstParam())
+ data().ImplicitCopyConstructorCanHaveConstParamForNonVBase = false;
}
// C++ [class.ctor]p3:
@@ -325,14 +342,6 @@
if (!BaseClassDecl->hasCopyAssignmentWithConstParam())
data().ImplicitCopyAssignmentHasConstParam = false;
- // C++11 [class.copy]p8:
- // The implicitly-declared copy constructor for a class X will have
- // the form 'X::X(const X&)' if each direct [...] base class B of X
- // has a copy constructor whose first parameter is of type
- // 'const B&' or 'const volatile B&' [...]
- if (!BaseClassDecl->hasCopyConstructorWithConstParam())
- data().ImplicitCopyConstructorHasConstParam = false;
-
// A class has an Objective-C object member if... or any of its bases
// has an Objective-C object member.
if (BaseClassDecl->hasObjectMember())
@@ -916,12 +925,11 @@
// C++11 [class.copy]p8:
// The implicitly-declared copy constructor for a class X will have
- // the form 'X::X(const X&)' if [...] for all the non-static data
- // members of X that are of a class type M (or array thereof), each
- // such class type has a copy constructor whose first parameter is
- // of type 'const M&' or 'const volatile M&'.
+ // the form 'X::X(const X&)' if each potentially constructed subobject
+ // of a class type M (or array thereof) has a copy constructor whose
+ // first parameter is of type 'const M&' or 'const volatile M&'.
if (!FieldRec->hasCopyConstructorWithConstParam())
- data().ImplicitCopyConstructorHasConstParam = false;
+ data().ImplicitCopyConstructorCanHaveConstParamForNonVBase = false;
// C++11 [class.copy]p18:
// The implicitly-declared copy assignment oeprator for a class X will