[PATCH] D135091: Create storage for the `_cmd` argument to the helper function for generated getters/setters of `direct` Objective-C properties.

[Michael Wyman via Phabricator via cfe-commits]

mwyman updated this revision to Diff 465925.
mwyman added a comment.
Herald added a subscriber: nlopes.

Use explicit `undef` for the `cmd` parameter to `objc_getProperty`/`objc_setProperty` rather declaring and not initializing storage for the implicit `_cmd`.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D135091/new/

https://reviews.llvm.org/D135091

Files:
  clang/lib/CodeGen/CGObjC.cpp
  clang/test/CodeGenObjC/direct-method.m


Index: clang/test/CodeGenObjC/direct-method.m
===================================================================
--- clang/test/CodeGenObjC/direct-method.m
+++ clang/test/CodeGenObjC/direct-method.m
@@ -14,6 +14,7 @@
 - (int)getInt __attribute__((objc_direct));
 @property(direct, readonly) int intProperty;
 @property(direct, readonly) int intProperty2;
+ at property(direct, readonly) id objectProperty;
 @end
 
 @implementation Root
@@ -167,6 +168,15 @@
 @end
 // CHECK-LABEL: define hidden i32 @"\01-[Root intProperty]"
 
+// Check the synthesized objectProperty calls objc_getProperty(); this also
+// checks that the synthesized method passes undef for the `cmd` argument.
+// CHECK-LABEL: define hidden i8* @"\01-[Root objectProperty]"(
+// CHECK-LABEL: objc_direct_method.cont:
+// CHECK-NEXT: [[SELFVAL:%.*]] = load {{.*}} %self.addr,
+// CHECK-NEXT: [[SELF:%.*]] = bitcast {{.*}} [[SELFVAL]] to i8*
+// CHECK-NEXT: [[IVAR:%.*]] = load {{.*}} @"OBJC_IVAR_$_Root._objectProperty",
+// CHECK-NEXT: call i8* @objc_getProperty(i8* noundef [[SELF]], i8* noundef undef, i64 noundef [[IVAR]], {{.*}})
+
 @interface Foo : Root {
   id __strong _cause_cxx_destruct;
 }
Index: clang/lib/CodeGen/CGObjC.cpp
===================================================================
--- clang/lib/CodeGen/CGObjC.cpp
+++ clang/lib/CodeGen/CGObjC.cpp
@@ -25,6 +25,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Analysis/ObjCARCUtil.h"
 #include "llvm/BinaryFormat/MachO.h"
+#include "llvm/IR/Constants.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/InlineAsm.h"
 using namespace clang;
@@ -1111,6 +1112,22 @@
                callee, ReturnValueSlot(), args);
 }
 
+// emitCmdLoadForGetterSetterBody - Handle emitting local storage declarations
+// for the `_cmd` argument that no longer exists for direct methods.
+static llvm::Value *emitCmdLoadForGetterSetterBody(CodeGenFunction &CGF,
+                                                   ObjCMethodDecl *MD) {
+  if (MD->isDirectMethod()) {
+    // Direct methods no longer have a `_cmd` argument, so storage must be
+    // emitted for it to be passed to the property helper. Since the `_cmd`
+    // argument was never being initialized by the caller before, still pass
+    // an uninitialized/undefined value here.
+    llvm::Type *selType = CGF.ConvertType(CGF.getContext().getObjCSelType());
+    return llvm::UndefValue::get(selType);
+  }
+
+  return CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(MD->getCmdDecl()), "cmd");
+}
+
 void
 CodeGenFunction::generateObjCGetterBody(const ObjCImplementationDecl *classImpl,
                                         const ObjCPropertyImplDecl *propImpl,
@@ -1189,8 +1206,7 @@
     // Return (ivar-type) objc_getProperty((id) self, _cmd, offset, true).
     // FIXME: Can't this be simpler? This might even be worse than the
     // corresponding gcc code.
-    llvm::Value *cmd =
-      Builder.CreateLoad(GetAddrOfLocalVar(getterMethod->getCmdDecl()), "cmd");
+    llvm::Value *cmd = emitCmdLoadForGetterSetterBody(*this, getterMethod);
     llvm::Value *self = Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
     llvm::Value *ivarOffset =
       EmitIvarOffset(classImpl->getClassInterface(), ivar);
@@ -1475,8 +1491,7 @@
 
     // Emit objc_setProperty((id) self, _cmd, offset, arg,
     //                       <is-atomic>, <is-copy>).
-    llvm::Value *cmd =
-      Builder.CreateLoad(GetAddrOfLocalVar(setterMethod->getCmdDecl()));
+    llvm::Value *cmd = emitCmdLoadForGetterSetterBody(*this, setterMethod);
     llvm::Value *self =
       Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
     llvm::Value *ivarOffset =


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