objective-C blocks: Make sure that identical logic is used

in deciding a copy/dispose field is needed in a byref structure
and when generating the copy/dispose helpers. In certain
cases, these fields were being added but no copy/dispose was
being generated. This was uncovered in ARC, but not in MRR.
// rdar://12759433


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@168825 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 36 insertions, 76 deletions

diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index c4dbf5d46f..7fee560534 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -4361,17 +4361,45 @@ QualType ASTContext::getBlockDescriptorExtendedType() const {
   return getTagDeclType(BlockDescriptorExtendedType);
 }
 
-bool ASTContext::BlockRequiresCopying(QualType Ty) const {
-  if (Ty->isObjCRetainableType())
+/// BlockRequiresCopying - Returns true if byref variable "D" of type "Ty"
+/// requires copy/dispose. Note that this must match the logic
+/// in buildByrefHelpers.
+bool ASTContext::BlockRequiresCopying(QualType Ty,
+                                      const VarDecl *D) {
+  if (const CXXRecordDecl *record = Ty->getAsCXXRecordDecl()) {
+    const Expr *copyExpr = getBlockVarCopyInits(D);
+    if (!copyExpr && record->hasTrivialDestructor()) return false;
+    
     return true;
-  if (getLangOpts().CPlusPlus) {
-    if (const RecordType *RT = Ty->getAs<RecordType>()) {
-      CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
-      return RD->hasConstCopyConstructor();
-      
+  }
+  
+  if (!Ty->isObjCRetainableType()) return false;
+  
+  Qualifiers qs = Ty.getQualifiers();
+  
+  // If we have lifetime, that dominates.
+  if (Qualifiers::ObjCLifetime lifetime = qs.getObjCLifetime()) {
+    assert(getLangOpts().ObjCAutoRefCount);
+    
+    switch (lifetime) {
+      case Qualifiers::OCL_None: llvm_unreachable("impossible");
+        
+      // These are just bits as far as the runtime is concerned.
+      case Qualifiers::OCL_ExplicitNone:
+      case Qualifiers::OCL_Autoreleasing:
+        return false;
+        
+      // Tell the runtime that this is ARC __weak, called by the
+      // byref routines.
+      case Qualifiers::OCL_Weak:
+      // ARC __strong __block variables need to be retained.
+      case Qualifiers::OCL_Strong:
+        return true;
     }
+    llvm_unreachable("fell out of lifetime switch!");
   }
-  return false;
+  return (Ty->isBlockPointerType() || isObjCNSObjectType(Ty) ||
+          Ty->isObjCObjectPointerType());
 }
 
 bool ASTContext::getByrefLifetime(QualType Ty,
@@ -4397,74 +4425,6 @@ bool ASTContext::getByrefLifetime(QualType Ty,
   return true;
 }
 
-QualType
-ASTContext::BuildByRefType(StringRef DeclName, QualType Ty) const {
-  //  type = struct __Block_byref_1_X {
-  //    void *__isa;
-  //    struct __Block_byref_1_X *__forwarding;
-  //    unsigned int __flags;
-  //    unsigned int __size;
-  //    void *__copy_helper;            // as needed
-  //    void *__destroy_help            // as needed
-  //    void *__byref_variable_layout;    // Extended layout info. for byref variable as needed
-  //    int X;
-  //  } *
-
-  bool HasCopyAndDispose = BlockRequiresCopying(Ty);
-  bool HasByrefExtendedLayout;
-  Qualifiers::ObjCLifetime Lifetime;
-
-  // FIXME: Move up
-  SmallString<36> Name;
-  llvm::raw_svector_ostream(Name) << "__Block_byref_" <<
-                                  ++UniqueBlockByRefTypeID << '_' << DeclName;
-  RecordDecl *T;
-  T = CreateRecordDecl(*this, TTK_Struct, TUDecl, &Idents.get(Name.str()));
-  T->startDefinition();
-  QualType Int32Ty = IntTy;
-  assert(getIntWidth(IntTy) == 32 && "non-32bit int not supported");
-  QualType FieldTypes[] = {
-    getPointerType(VoidPtrTy),
-    getPointerType(getTagDeclType(T)),
-    Int32Ty,
-    Int32Ty,
-    getPointerType(VoidPtrTy),
-    getPointerType(VoidPtrTy),
-    getPointerType(VoidPtrTy),
-    Ty
-  };
-
-  StringRef FieldNames[] = {
-    "__isa",
-    "__forwarding",
-    "__flags",
-    "__size",
-    "__copy_helper",
-    "__destroy_helper",
-    "__byref_variable_layout",
-    DeclName,
-  };
-  bool ByrefKnownLifetime = getByrefLifetime(Ty, Lifetime, HasByrefExtendedLayout);
-  for (size_t i = 0; i < 8; ++i) {
-    if (!HasCopyAndDispose && i >=4 && i <= 5)
-      continue;
-    if ((!ByrefKnownLifetime || !HasByrefExtendedLayout) && i == 6)
-      continue;
-    FieldDecl *Field = FieldDecl::Create(*this, T, SourceLocation(),
-                                         SourceLocation(),
-                                         &Idents.get(FieldNames[i]),
-                                         FieldTypes[i], /*TInfo=*/0,
-                                         /*BitWidth=*/0, /*Mutable=*/false,
-                                         ICIS_NoInit);
-    Field->setAccess(AS_public);
-    T->addDecl(Field);
-  }
-
-  T->completeDefinition();
-
-  return getPointerType(getTagDeclType(T));
-}
-
 TypedefDecl *ASTContext::getObjCInstanceTypeDecl() {
   if (!ObjCInstanceTypeDecl)
     ObjCInstanceTypeDecl = TypedefDecl::Create(*this,