Emit errors about unsupported blocks features.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@65751 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGBlocks.cpp b/lib/CodeGen/CGBlocks.cpp
index 93e1b57..ba9480f 100644
--- a/lib/CodeGen/CGBlocks.cpp
+++ b/lib/CodeGen/CGBlocks.cpp
@@ -132,6 +132,44 @@
   return Info.ByRefDeclRefs.empty() && Info.ByCopyDeclRefs.empty();
 }
 
+/// CanGenerateCodeForBlockExpr - Returns whether CodeGen for the block expr
+/// is supported. Will emit a diagnostic and return false if not.
+/// FIXME: Once we support everything this should of course be removed.
+static bool CanGenerateCodeForBlockExpr(CodeGenFunction &CGF, 
+                                        const BlockExpr* BE, 
+                                        const CodeGenFunction::BlockInfo &Info)
+{
+  if (!Info.ByRefDeclRefs.empty()) {
+    CGF.ErrorUnsupported(BE, "block expression with __block variables");
+    return false;
+  }
+  
+  for (size_t I = 0, E = Info.ByCopyDeclRefs.size(); I != E; ++I) {
+    const BlockDeclRefExpr *E = Info.ByCopyDeclRefs[I];
+    
+    E->getType()->dump();
+    
+    if (E->getType()->isBlockPointerType()) {
+      CGF.ErrorUnsupported(BE, "block expression with imported block");
+      return false;
+    }
+    
+    if (E->getDecl()->getAttr<ObjCNSObjectAttr>() || 
+        CGF.getContext().isObjCNSObjectType(E->getType())) {
+      CGF.ErrorUnsupported(BE, "block expression with __attribute__((NSObject))"
+                           " variable");
+      return false;
+    }
+    
+    if (CGF.getContext().isObjCObjectPointerType(E->getType())) {
+      CGF.ErrorUnsupported(BE, "block expression with Objective-C variable");
+      return false;
+    }
+  }
+  
+  return true;
+}
+
 // FIXME: Push most into CGM, passing down a few bits, like current
 // function name.
 llvm::Value *CodeGenFunction::BuildBlockLiteralTmp(const BlockExpr *BE) {
@@ -144,6 +182,9 @@
   if (CanBlockBeGlobal(Info))
     return CGM.GetAddrOfGlobalBlock(BE, Name.c_str());
     
+  if (!CanGenerateCodeForBlockExpr(*this, BE, Info))
+    return llvm::UndefValue::get(ConvertType(BE->getType()));
+  
   std::vector<llvm::Constant*> Elts;
   llvm::Constant *C;
   llvm::Value *V;