This change is breaking selfhost. Revert it until I have more time

to study it.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@132843 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 187 insertions, 82 deletions

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 863ab8ce61..a4ba5fafea 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -3523,7 +3523,7 @@ bool Sema::ShouldDeleteCopyConstructor(CXXConstructorDecl *CD) {
     //    resolution, as applied to B's [copy] constructor, results in an
     //    ambiguity or a function that is deleted or inaccessible from the
     //    defaulted constructor
-    CXXConstructorDecl *BaseCtor = LookupCopyingConstructor(BaseDecl, ArgQuals);
+    CXXConstructorDecl *BaseCtor = LookupCopyConstructor(BaseDecl, ArgQuals);
     if (!BaseCtor || BaseCtor->isDeleted())
       return true;
     if (CheckConstructorAccess(Loc, BaseCtor, BaseCtor->getAccess(), PDiag()) !=
@@ -3551,7 +3551,7 @@ bool Sema::ShouldDeleteCopyConstructor(CXXConstructorDecl *CD) {
     //    resolution, as applied to B's [copy] constructor, results in an
     //    ambiguity or a function that is deleted or inaccessible from the
     //    defaulted constructor
-    CXXConstructorDecl *BaseCtor = LookupCopyingConstructor(BaseDecl, ArgQuals);
+    CXXConstructorDecl *BaseCtor = LookupCopyConstructor(BaseDecl, ArgQuals);
     if (!BaseCtor || BaseCtor->isDeleted())
       return true;
     if (CheckConstructorAccess(Loc, BaseCtor, BaseCtor->getAccess(), PDiag()) !=
@@ -3613,8 +3613,8 @@ bool Sema::ShouldDeleteCopyConstructor(CXXConstructorDecl *CD) {
     //    cannot be [copied] because overload resolution, as applied to B's
     //    [copy] constructor, results in an ambiguity or a function that is
     //    deleted or inaccessible from the defaulted constructor
-      CXXConstructorDecl *FieldCtor = LookupCopyingConstructor(FieldRecord,
-                                                               ArgQuals);
+      CXXConstructorDecl *FieldCtor = LookupCopyConstructor(FieldRecord,
+                                                            ArgQuals);
       if (!FieldCtor || FieldCtor->isDeleted())
         return true;
       if (CheckConstructorAccess(Loc, FieldCtor, FieldCtor->getAccess(),
@@ -3639,15 +3639,19 @@ bool Sema::ShouldDeleteCopyAssignmentOperator(CXXMethodDecl *MD) {
 
   bool Union = RD->isUnion();
 
-  unsigned ArgQuals =
-    MD->getParamDecl(0)->getType()->getPointeeType().isConstQualified() ?
-      Qualifiers::Const : 0;
+  bool ConstArg =
+    MD->getParamDecl(0)->getType()->getPointeeType().isConstQualified();
 
   // We do this because we should never actually use an anonymous
   // union's constructor.
   if (Union && RD->isAnonymousStructOrUnion())
     return false;
 
+  DeclarationName OperatorName =
+    Context.DeclarationNames.getCXXOperatorName(OO_Equal);
+  LookupResult R(*this, OperatorName, Loc, LookupOrdinaryName);
+  R.suppressDiagnostics();
+
   // FIXME: We should put some diagnostic logic right into this function.
 
   // C++0x [class.copy]/11
@@ -3669,11 +3673,37 @@ bool Sema::ShouldDeleteCopyAssignmentOperator(CXXMethodDecl *MD) {
     //    resolution, as applied to B's [copy] assignment operator, results in
     //    an ambiguity or a function that is deleted or inaccessible from the
     //    assignment operator
-    CXXMethodDecl *CopyOper = LookupCopyingAssignment(BaseDecl, ArgQuals, false,
-                                                      0);
-    if (!CopyOper || CopyOper->isDeleted())
-      return true;
-    if (CheckDirectMemberAccess(Loc, CopyOper, PDiag()) != AR_accessible)
+
+    LookupQualifiedName(R, BaseDecl, false);
+
+    // Filter out any result that isn't a copy-assignment operator.
+    LookupResult::Filter F = R.makeFilter();
+    while (F.hasNext()) {
+      NamedDecl *D = F.next();
+      if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D))
+        if (Method->isCopyAssignmentOperator())
+          continue;
+      
+      F.erase();
+    }
+    F.done();
+ 
+    // Build a fake argument expression
+    QualType ArgType = BaseType;
+    QualType ThisType = BaseType;
+    if (ConstArg)
+      ArgType.addConst();
+    Expr *Args[] = { new (Context) OpaqueValueExpr(Loc, ThisType, VK_LValue)
+                   , new (Context) OpaqueValueExpr(Loc, ArgType, VK_LValue)
+                   };
+
+    OverloadCandidateSet OCS((Loc));
+    OverloadCandidateSet::iterator Best;
+
+    AddFunctionCandidates(R.asUnresolvedSet(), Args, 2, OCS);
+
+    if (OCS.BestViableFunction(*this, Loc, Best, false) !=
+        OR_Success)
       return true;
   }
 
@@ -3688,11 +3718,37 @@ bool Sema::ShouldDeleteCopyAssignmentOperator(CXXMethodDecl *MD) {
     //    resolution, as applied to B's [copy] assignment operator, results in
     //    an ambiguity or a function that is deleted or inaccessible from the
     //    assignment operator
-    CXXMethodDecl *CopyOper = LookupCopyingAssignment(BaseDecl, ArgQuals, false,
-                                                      0);
-    if (!CopyOper || CopyOper->isDeleted())
-      return true;
-    if (CheckDirectMemberAccess(Loc, CopyOper, PDiag()) != AR_accessible)
+
+    LookupQualifiedName(R, BaseDecl, false);
+
+    // Filter out any result that isn't a copy-assignment operator.
+    LookupResult::Filter F = R.makeFilter();
+    while (F.hasNext()) {
+      NamedDecl *D = F.next();
+      if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D))
+        if (Method->isCopyAssignmentOperator())
+          continue;
+      
+      F.erase();
+    }
+    F.done();
+ 
+    // Build a fake argument expression
+    QualType ArgType = BaseType;
+    QualType ThisType = BaseType;
+    if (ConstArg)
+      ArgType.addConst();
+    Expr *Args[] = { new (Context) OpaqueValueExpr(Loc, ThisType, VK_LValue)
+                   , new (Context) OpaqueValueExpr(Loc, ArgType, VK_LValue)
+                   };
+
+    OverloadCandidateSet OCS((Loc));
+    OverloadCandidateSet::iterator Best;
+
+    AddFunctionCandidates(R.asUnresolvedSet(), Args, 2, OCS);
+
+    if (OCS.BestViableFunction(*this, Loc, Best, false) !=
+        OR_Success)
       return true;
   }
 
@@ -3739,12 +3795,37 @@ bool Sema::ShouldDeleteCopyAssignmentOperator(CXXMethodDecl *MD) {
           return true;
       }
 
-      CXXMethodDecl *CopyOper = LookupCopyingAssignment(FieldRecord, ArgQuals,
-                                                        false, 0);
-      if (!CopyOper || CopyOper->isDeleted())
-        return false;
-      if (CheckDirectMemberAccess(Loc, CopyOper, PDiag()) != AR_accessible)
-        return false;
+      LookupQualifiedName(R, FieldRecord, false);
+
+      // Filter out any result that isn't a copy-assignment operator.
+      LookupResult::Filter F = R.makeFilter();
+      while (F.hasNext()) {
+        NamedDecl *D = F.next();
+        if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D))
+          if (Method->isCopyAssignmentOperator())
+            continue;
+        
+        F.erase();
+      }
+      F.done();
+   
+      // Build a fake argument expression
+      QualType ArgType = FieldType;
+      QualType ThisType = FieldType;
+      if (ConstArg)
+        ArgType.addConst();
+      Expr *Args[] = { new (Context) OpaqueValueExpr(Loc, ThisType, VK_LValue)
+                     , new (Context) OpaqueValueExpr(Loc, ArgType, VK_LValue)
+                     };
+
+      OverloadCandidateSet OCS((Loc));
+      OverloadCandidateSet::iterator Best;
+
+      AddFunctionCandidates(R.asUnresolvedSet(), Args, 2, OCS);
+
+      if (OCS.BestViableFunction(*this, Loc, Best, false) !=
+          OR_Success)
+        return true;
     }
   }
 
@@ -6433,6 +6514,58 @@ BuildSingleCopyAssign(Sema &S, SourceLocation Loc, QualType T,
                         Loc, Copy.take());
 }
 
+/// \brief Determine whether the given class has a copy assignment operator 
+/// that accepts a const-qualified argument.
+static bool hasConstCopyAssignment(Sema &S, const CXXRecordDecl *CClass) {
+  CXXRecordDecl *Class = const_cast<CXXRecordDecl *>(CClass);
+  
+  if (!Class->hasDeclaredCopyAssignment())
+    S.DeclareImplicitCopyAssignment(Class);
+  
+  QualType ClassType = S.Context.getCanonicalType(S.Context.getTypeDeclType(Class));
+  DeclarationName OpName 
+    = S.Context.DeclarationNames.getCXXOperatorName(OO_Equal);
+    
+  DeclContext::lookup_const_iterator Op, OpEnd;
+  for (llvm::tie(Op, OpEnd) = Class->lookup(OpName); Op != OpEnd; ++Op) {
+    // C++ [class.copy]p9:
+    //   A user-declared copy assignment operator is a non-static non-template
+    //   member function of class X with exactly one parameter of type X, X&,
+    //   const X&, volatile X& or const volatile X&.
+    const CXXMethodDecl* Method = dyn_cast<CXXMethodDecl>(*Op);
+    if (!Method)
+      continue;
+    
+    if (Method->isStatic())
+      continue;
+    if (Method->getPrimaryTemplate())
+      continue;
+    const FunctionProtoType *FnType =
+    Method->getType()->getAs<FunctionProtoType>();
+    assert(FnType && "Overloaded operator has no prototype.");
+    // Don't assert on this; an invalid decl might have been left in the AST.
+    if (FnType->getNumArgs() != 1 || FnType->isVariadic())
+      continue;
+    bool AcceptsConst = true;
+    QualType ArgType = FnType->getArgType(0);
+    if (const LValueReferenceType *Ref = ArgType->getAs<LValueReferenceType>()){
+      ArgType = Ref->getPointeeType();
+      // Is it a non-const lvalue reference?
+      if (!ArgType.isConstQualified())
+        AcceptsConst = false;
+    }
+    if (!S.Context.hasSameUnqualifiedType(ArgType, ClassType))
+      continue;
+    
+    // We have a single argument of type cv X or cv X&, i.e. we've found the
+    // copy assignment operator. Return whether it accepts const arguments.
+    return AcceptsConst;
+  }
+  assert(Class->isInvalidDecl() &&
+         "No copy assignment operator declared in valid code.");
+  return false;  
+}
+
 std::pair<Sema::ImplicitExceptionSpecification, bool>
 Sema::ComputeDefaultedCopyAssignmentExceptionSpecAndConst(
                                                    CXXRecordDecl *ClassDecl) {
@@ -6453,28 +6586,11 @@ Sema::ComputeDefaultedCopyAssignmentExceptionSpecAndConst(
   for (CXXRecordDecl::base_class_iterator Base = ClassDecl->bases_begin(),
                                        BaseEnd = ClassDecl->bases_end();
        HasConstCopyAssignment && Base != BaseEnd; ++Base) {
-    // We'll handle this below
-    if (LangOpts.CPlusPlus0x && Base->isVirtual())
-      continue;
-
     assert(!Base->getType()->isDependentType() &&
            "Cannot generate implicit members for class with dependent bases.");
-    CXXRecordDecl *BaseClassDecl = Base->getType()->getAsCXXRecordDecl();
-    LookupCopyingAssignment(BaseClassDecl, Qualifiers::Const, false, 0,
-                            &HasConstCopyAssignment);
-  }
-
-  // In C++0x, the above citation has "or virtual added"
-  if (LangOpts.CPlusPlus0x) {
-    for (CXXRecordDecl::base_class_iterator Base = ClassDecl->vbases_begin(),
-                                         BaseEnd = ClassDecl->vbases_end();
-         HasConstCopyAssignment && Base != BaseEnd; ++Base) {
-      assert(!Base->getType()->isDependentType() &&
-             "Cannot generate implicit members for class with dependent bases.");
-      CXXRecordDecl *BaseClassDecl = Base->getType()->getAsCXXRecordDecl();
-      LookupCopyingAssignment(BaseClassDecl, Qualifiers::Const, false, 0,
-                              &HasConstCopyAssignment);
-    }
+    const CXXRecordDecl *BaseClassDecl
+      = cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
+    HasConstCopyAssignment = hasConstCopyAssignment(*this, BaseClassDecl);
   }
   
   //       -- for all the nonstatic data members of X that are of a class
@@ -6486,9 +6602,10 @@ Sema::ComputeDefaultedCopyAssignmentExceptionSpecAndConst(
        HasConstCopyAssignment && Field != FieldEnd;
        ++Field) {
     QualType FieldType = Context.getBaseElementType((*Field)->getType());
-    if (CXXRecordDecl *FieldClassDecl = FieldType->getAsCXXRecordDecl()) {
-      LookupCopyingAssignment(FieldClassDecl, Qualifiers::Const, false, 0,
-                              &HasConstCopyAssignment);
+    if (const RecordType *FieldClassType = FieldType->getAs<RecordType>()) {
+      const CXXRecordDecl *FieldClassDecl
+        = cast<CXXRecordDecl>(FieldClassType->getDecl());
+      HasConstCopyAssignment = hasConstCopyAssignment(*this, FieldClassDecl);
     }
   }
   
@@ -6500,47 +6617,35 @@ Sema::ComputeDefaultedCopyAssignmentExceptionSpecAndConst(
   // C++ [except.spec]p14:
   //   An implicitly declared special member function (Clause 12) shall have an 
   //   exception-specification. [...]
-
-  // It is unspecified whether or not an implicit copy assignment operator
-  // attempts to deduplicate calls to assignment operators of virtual bases are
-  // made. As such, this exception specification is effectively unspecified.
-  // Based on a similar decision made for constness in C++0x, we're erring on
-  // the side of assuming such calls to be made regardless of whether they
-  // actually happen.
   ImplicitExceptionSpecification ExceptSpec(Context);
-  unsigned ArgQuals = HasConstCopyAssignment ? Qualifiers::Const : 0;
   for (CXXRecordDecl::base_class_iterator Base = ClassDecl->bases_begin(),
                                        BaseEnd = ClassDecl->bases_end();
        Base != BaseEnd; ++Base) {
-    if (Base->isVirtual())
-      continue;
-
     CXXRecordDecl *BaseClassDecl
       = cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
-    if (CXXMethodDecl *CopyAssign = LookupCopyingAssignment(BaseClassDecl,
-                                                            ArgQuals, false, 0))
-      ExceptSpec.CalledDecl(CopyAssign);
-  }
+    
+    if (!BaseClassDecl->hasDeclaredCopyAssignment())
+      DeclareImplicitCopyAssignment(BaseClassDecl);
 
-  for (CXXRecordDecl::base_class_iterator Base = ClassDecl->vbases_begin(),
-                                       BaseEnd = ClassDecl->vbases_end();
-       Base != BaseEnd; ++Base) {
-    CXXRecordDecl *BaseClassDecl
-      = cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
-    if (CXXMethodDecl *CopyAssign = LookupCopyingAssignment(BaseClassDecl,
-                                                            ArgQuals, false, 0))
+    if (CXXMethodDecl *CopyAssign
+           = BaseClassDecl->getCopyAssignmentOperator(HasConstCopyAssignment))
       ExceptSpec.CalledDecl(CopyAssign);
   }
-
   for (CXXRecordDecl::field_iterator Field = ClassDecl->field_begin(),
                                   FieldEnd = ClassDecl->field_end();
        Field != FieldEnd;
        ++Field) {
     QualType FieldType = Context.getBaseElementType((*Field)->getType());
-    if (CXXRecordDecl *FieldClassDecl = FieldType->getAsCXXRecordDecl()) {
-      if (CXXMethodDecl *CopyAssign =
-          LookupCopyingAssignment(FieldClassDecl, ArgQuals, false, 0))
-        ExceptSpec.CalledDecl(CopyAssign);
+    if (const RecordType *FieldClassType = FieldType->getAs<RecordType>()) {
+      CXXRecordDecl *FieldClassDecl
+        = cast<CXXRecordDecl>(FieldClassType->getDecl());
+      
+      if (!FieldClassDecl->hasDeclaredCopyAssignment())
+        DeclareImplicitCopyAssignment(FieldClassDecl);
+
+      if (CXXMethodDecl *CopyAssign
+            = FieldClassDecl->getCopyAssignmentOperator(HasConstCopyAssignment))
+        ExceptSpec.CalledDecl(CopyAssign);      
     }      
   }
 
@@ -6924,8 +7029,8 @@ Sema::ComputeDefaultedCopyCtorExceptionSpecAndConst(CXXRecordDecl *ClassDecl) {
     
     CXXRecordDecl *BaseClassDecl
       = cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
-    LookupCopyingConstructor(BaseClassDecl, Qualifiers::Const,
-                             &HasConstCopyConstructor);
+    LookupCopyConstructor(BaseClassDecl, Qualifiers::Const,
+                          &HasConstCopyConstructor);
   }
 
   for (CXXRecordDecl::base_class_iterator Base = ClassDecl->vbases_begin(),
@@ -6934,8 +7039,8 @@ Sema::ComputeDefaultedCopyCtorExceptionSpecAndConst(CXXRecordDecl *ClassDecl) {
        ++Base) {
     CXXRecordDecl *BaseClassDecl
       = cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
-    LookupCopyingConstructor(BaseClassDecl, Qualifiers::Const,
-                             &HasConstCopyConstructor);
+    LookupCopyConstructor(BaseClassDecl, Qualifiers::Const,
+                          &HasConstCopyConstructor);
   }
   
   //     -- for all the nonstatic data members of X that are of a
@@ -6948,8 +7053,8 @@ Sema::ComputeDefaultedCopyCtorExceptionSpecAndConst(CXXRecordDecl *ClassDecl) {
        ++Field) {
     QualType FieldType = Context.getBaseElementType((*Field)->getType());
     if (CXXRecordDecl *FieldClassDecl = FieldType->getAsCXXRecordDecl()) {
-      LookupCopyingConstructor(FieldClassDecl, Qualifiers::Const,
-                               &HasConstCopyConstructor);
+      LookupCopyConstructor(FieldClassDecl, Qualifiers::Const,
+                            &HasConstCopyConstructor);
     }
   }
   //   Otherwise, the implicitly declared copy constructor will have
@@ -6973,7 +7078,7 @@ Sema::ComputeDefaultedCopyCtorExceptionSpecAndConst(CXXRecordDecl *ClassDecl) {
     CXXRecordDecl *BaseClassDecl
       = cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
     if (CXXConstructorDecl *CopyConstructor =
-          LookupCopyingConstructor(BaseClassDecl, Quals))
+          LookupCopyConstructor(BaseClassDecl, Quals))
       ExceptSpec.CalledDecl(CopyConstructor);
   }
   for (CXXRecordDecl::base_class_iterator Base = ClassDecl->vbases_begin(),
@@ -6983,7 +7088,7 @@ Sema::ComputeDefaultedCopyCtorExceptionSpecAndConst(CXXRecordDecl *ClassDecl) {
     CXXRecordDecl *BaseClassDecl
       = cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
     if (CXXConstructorDecl *CopyConstructor =
-          LookupCopyingConstructor(BaseClassDecl, Quals))
+          LookupCopyConstructor(BaseClassDecl, Quals))
       ExceptSpec.CalledDecl(CopyConstructor);
   }
   for (CXXRecordDecl::field_iterator Field = ClassDecl->field_begin(),
@@ -6993,7 +7098,7 @@ Sema::ComputeDefaultedCopyCtorExceptionSpecAndConst(CXXRecordDecl *ClassDecl) {
     QualType FieldType = Context.getBaseElementType((*Field)->getType());
     if (CXXRecordDecl *FieldClassDecl = FieldType->getAsCXXRecordDecl()) {
       if (CXXConstructorDecl *CopyConstructor =
-        LookupCopyingConstructor(FieldClassDecl, Quals))
+        LookupCopyConstructor(FieldClassDecl, Quals))
       ExceptSpec.CalledDecl(CopyConstructor);
     }
   }