Add ARC support for the GNUstep runtime.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134065 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGObjCGNU.cpp

@@ -392,6 +392,8 @@ private:
   /// Emits a reference to a class.  This allows the linker to object if there
   /// is no class of the matching name.
   void EmitClassRef(const std::string &className);
+  /// Emits a pointer to the named class
+  llvm::Value *GetClassNamed(CGBuilderTy &Builder, const std::string &Name);
 protected:
   /// Looks up the method for sending a message to the specified object.  This
   /// mechanism differs between the GCC and GNU runtimes, so this method must be
@@ -484,6 +486,7 @@ public:
   virtual llvm::Value *EmitIvarOffset(CodeGenFunction &CGF,
                                       const ObjCInterfaceDecl *Interface,
                                       const ObjCIvarDecl *Ivar);
+  virtual llvm::Value *EmitNSAutoreleasePoolClassRef(CGBuilderTy &Builder);
   virtual llvm::Constant *BuildGCBlockLayout(CodeGenModule &CGM,
                                              const CGBlockInfo &blockInfo) {
     return NULLPtr;
@@ -772,16 +775,17 @@ CGObjCGNU::CGObjCGNU(CodeGenModule &cgm, unsigned runtimeABIVersion,
   }
 }
 
-// This has to perform the lookup every time, since posing and related
-// techniques can modify the name -> class mapping.
-llvm::Value *CGObjCGNU::GetClass(CGBuilderTy &Builder,
-                                 const ObjCInterfaceDecl *OID) {
-  llvm::Value *ClassName = CGM.GetAddrOfConstantCString(OID->getNameAsString());
+llvm::Value *CGObjCGNU::GetClassNamed(CGBuilderTy &Builder,
+                                      const std::string &Name) {
+  llvm::Value *ClassName = CGM.GetAddrOfConstantCString(Name);
   // With the incompatible ABI, this will need to be replaced with a direct
   // reference to the class symbol.  For the compatible nonfragile ABI we are
   // still performing this lookup at run time but emitting the symbol for the
   // class externally so that we can make the switch later.
-  EmitClassRef(OID->getNameAsString());
+  //
+  // Libobjc2 contains an LLVM pass that replaces calls to objc_lookup_class
+  // with memoized versions or with static references if it's safe to do so.
+  EmitClassRef(Name);
   ClassName = Builder.CreateStructGEP(ClassName, 0);
 
   llvm::Constant *ClassLookupFn =
@@ -790,6 +794,16 @@ llvm::Value *CGObjCGNU::GetClass(CGBuilderTy &Builder,
   return Builder.CreateCall(ClassLookupFn, ClassName);
 }
 
+// This has to perform the lookup every time, since posing and related
+// techniques can modify the name -> class mapping.
+llvm::Value *CGObjCGNU::GetClass(CGBuilderTy &Builder,
+                                 const ObjCInterfaceDecl *OID) {
+  return GetClassNamed(Builder, OID->getNameAsString());
+}
+llvm::Value *CGObjCGNU::EmitNSAutoreleasePoolClassRef(CGBuilderTy &Builder) {
+  return GetClassNamed(Builder, "NSAutoreleasePool");
+}
+
 llvm::Value *CGObjCGNU::GetSelector(CGBuilderTy &Builder, Selector Sel,
     const std::string &TypeEncoding, bool lval) {