Patch to fix IR-gen crash generating structure ABI which implements
user specified string class via -fconstant-string-class option.
pr9914.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@131496 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGObjCGNU.cpp b/lib/CodeGen/CGObjCGNU.cpp
index c4dc4c4..7cf4f0b 100644
--- a/lib/CodeGen/CGObjCGNU.cpp
+++ b/lib/CodeGen/CGObjCGNU.cpp
@@ -484,6 +484,10 @@
                                              const CGBlockInfo &blockInfo) {
     return NULLPtr;
   }
+  
+  virtual llvm::GlobalVariable *GetClassGlobal(const std::string &Name) {
+    return 0;
+  }
 };
 /// Class representing the legacy GCC Objective-C ABI.  This is the default when
 /// -fobjc-nonfragile-abi is not specified.
diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 50f2c78..99d464f 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -1048,6 +1048,13 @@
   virtual llvm::Value *EmitIvarOffset(CodeGen::CodeGenFunction &CGF,
                                       const ObjCInterfaceDecl *Interface,
                                       const ObjCIvarDecl *Ivar);
+  
+  /// GetClassGlobal - Return the global variable for the Objective-C
+  /// class of the given name.
+  virtual llvm::GlobalVariable *GetClassGlobal(const std::string &Name) {
+    assert(false && "CGObjCMac::GetClassGlobal");
+    return 0;
+  }
 };
 
 class CGObjCNonFragileABIMac : public CGObjCCommonMac {
@@ -1142,11 +1149,11 @@
                                         bool IsSuper,
                                         const CallArgList &CallArgs,
                                         const ObjCMethodDecl *Method);
-
+  
   /// GetClassGlobal - Return the global variable for the Objective-C
   /// class of the given name.
   llvm::GlobalVariable *GetClassGlobal(const std::string &Name);
-
+    
   /// EmitClassRef - Return a Value*, of type ObjCTypes.ClassPtrTy,
   /// for the given class reference.
   llvm::Value *EmitClassRef(CGBuilderTy &Builder,
diff --git a/lib/CodeGen/CGObjCRuntime.h b/lib/CodeGen/CGObjCRuntime.h
index 0cc2d82..fdb58d9 100644
--- a/lib/CodeGen/CGObjCRuntime.h
+++ b/lib/CodeGen/CGObjCRuntime.h
@@ -243,6 +243,7 @@
                                         llvm::Value *Size) = 0;
   virtual llvm::Constant *BuildGCBlockLayout(CodeGen::CodeGenModule &CGM,
                                   const CodeGen::CGBlockInfo &blockInfo) = 0;
+  virtual llvm::GlobalVariable *GetClassGlobal(const std::string &Name) = 0;
 };
 
 /// Creates an instance of an Objective-C runtime class.
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 84fa4af..7f2e3f5 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -1768,24 +1768,31 @@
   if (!ConstantStringClassRef) {
     std::string StringClass(getLangOptions().ObjCConstantStringClass);
     const llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy);
-    Ty = llvm::ArrayType::get(Ty, 0);
     llvm::Constant *GV;
-    if (StringClass.empty())
-      GV = CreateRuntimeVariable(Ty, 
-                                 Features.ObjCNonFragileABI ?
-                                 "OBJC_CLASS_$_NSConstantString" :
-                                 "_NSConstantStringClassReference");
-    else {
+    if (Features.ObjCNonFragileABI) {
       std::string str;
-      if (Features.ObjCNonFragileABI)
+      if (StringClass.empty())
+        str = "OBJC_CLASS_$_NSConstantString";
+      else {
         str = "OBJC_CLASS_$_" + StringClass;
-      else
-        str = "_" + StringClass + "ClassReference";
-      GV = CreateRuntimeVariable(Ty, str);
+      }
+      GV = getObjCRuntime().GetClassGlobal(str);
+      // Make sure the result is of the correct type.
+      const llvm::Type *PTy = llvm::PointerType::getUnqual(Ty);
+      ConstantStringClassRef =
+        llvm::ConstantExpr::getBitCast(GV, PTy);
+    } else {
+      Ty = llvm::ArrayType::get(Ty, 0);
+      if (StringClass.empty())
+        GV = CreateRuntimeVariable(Ty, "_NSConstantStringClassReference");
+      else {
+        std::string str = "_" + StringClass + "ClassReference";
+        GV = CreateRuntimeVariable(Ty, str);
+      }
+      // Decay array -> ptr
+      ConstantStringClassRef = 
+        llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2);
     }
-    // Decay array -> ptr
-    ConstantStringClassRef = 
-    llvm::ConstantExpr::getGetElementPtr(GV, Zeros, 2);
   }
   
   QualType NSTy = getContext().getNSConstantStringType();