Objective-C doesn't consider the use of incomplete types as method
parameter types to be ill-formed. However, it relies on the
completeness of method parameter types when producing metadata, e.g.,
for a protocol, leading IR generating to crash in such cases.

Since there's no real way to tighten down the semantics of Objective-C
here without breaking existing code, do something safe but lame:
suppress the generation of metadata when this happens.

Fixes <rdar://problem/9123036>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@132171 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 99d464f..520d94e 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -1686,6 +1686,7 @@
 llvm::Constant *CGObjCCommonMac::GetProtocolRef(const ObjCProtocolDecl *PD) {
   if (DefinedProtocols.count(PD->getIdentifier()))
     return GetOrEmitProtocol(PD);
+  
   return GetOrEmitProtocolRef(PD);
 }
 
@@ -1719,6 +1720,9 @@
          i = PD->instmeth_begin(), e = PD->instmeth_end(); i != e; ++i) {
     ObjCMethodDecl *MD = *i;
     llvm::Constant *C = GetMethodDescriptionConstant(MD);
+    if (!C)
+      return GetOrEmitProtocolRef(PD);
+    
     if (MD->getImplementationControl() == ObjCMethodDecl::Optional) {
       OptInstanceMethods.push_back(C);
     } else {
@@ -1730,6 +1734,9 @@
          i = PD->classmeth_begin(), e = PD->classmeth_end(); i != e; ++i) {
     ObjCMethodDecl *MD = *i;
     llvm::Constant *C = GetMethodDescriptionConstant(MD);
+    if (!C)
+      return GetOrEmitProtocolRef(PD);
+
     if (MD->getImplementationControl() == ObjCMethodDecl::Optional) {
       OptClassMethods.push_back(C);
     } else {
@@ -1973,6 +1980,9 @@
     llvm::ConstantExpr::getBitCast(GetMethodVarName(MD->getSelector()),
                                    ObjCTypes.SelectorPtrTy);
   Desc[1] = GetMethodVarType(MD);
+  if (!Desc[1])
+    return 0;
+  
   return llvm::ConstantStruct::get(ObjCTypes.MethodDescriptionTy,
                                    Desc);
 }
@@ -3935,8 +3945,10 @@
 
 llvm::Constant *CGObjCCommonMac::GetMethodVarType(const ObjCMethodDecl *D) {
   std::string TypeStr;
-  CGM.getContext().getObjCEncodingForMethodDecl(const_cast<ObjCMethodDecl*>(D),
-                                                TypeStr);
+  if (CGM.getContext().getObjCEncodingForMethodDecl(
+                                                const_cast<ObjCMethodDecl*>(D),
+                                                    TypeStr))
+    return 0;
 
   llvm::GlobalVariable *&Entry = MethodVarTypes[TypeStr];
 
@@ -5359,6 +5371,9 @@
          i = PD->instmeth_begin(), e = PD->instmeth_end(); i != e; ++i) {
     ObjCMethodDecl *MD = *i;
     llvm::Constant *C = GetMethodDescriptionConstant(MD);
+    if (!C)
+      return GetOrEmitProtocolRef(PD);
+    
     if (MD->getImplementationControl() == ObjCMethodDecl::Optional) {
       OptInstanceMethods.push_back(C);
     } else {
@@ -5370,6 +5385,9 @@
          i = PD->classmeth_begin(), e = PD->classmeth_end(); i != e; ++i) {
     ObjCMethodDecl *MD = *i;
     llvm::Constant *C = GetMethodDescriptionConstant(MD);
+    if (!C)
+      return GetOrEmitProtocolRef(PD);
+
     if (MD->getImplementationControl() == ObjCMethodDecl::Optional) {
       OptClassMethods.push_back(C);
     } else {
@@ -5509,6 +5527,9 @@
     llvm::ConstantExpr::getBitCast(GetMethodVarName(MD->getSelector()),
                                    ObjCTypes.SelectorPtrTy);
   Desc[1] = GetMethodVarType(MD);
+  if (!Desc[1])
+    return 0;
+  
   // Protocol methods have no implementation. So, this entry is always NULL.
   Desc[2] = llvm::Constant::getNullValue(ObjCTypes.Int8PtrTy);
   return llvm::ConstantStruct::get(ObjCTypes.MethodTy, Desc);