[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 465857.
mwyman retitled this revision from "Load the `_cmd` selector for generated getters/setters of `direct` Objective-C properties." to "Create storage for the `_cmd` argument to the helper function for generated getters/setters of `direct` Objective-C properties.".
mwyman edited the summary of this revision.
mwyman added a comment.

Updated to eliminate loading the selector, as the prior implementation didn't pass a valid `_cmd` value (it just re-used the `_cmd` argument in the ABI, which was unset by the caller and so undefined in value).


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 +168,18 @@
 @end
 // CHECK-LABEL: define hidden i32 @"\01-[Root intProperty]"
 
+// Check the synthesized objectProperty calls objc_getProperty(); this also
+// checks that the synthesized method accesses _cmd (or rather loads the
+// selector, as it is an argument to objc_getProperty).
+// CHECK-LABEL: define hidden i8* @"\01-[Root objectProperty]"(
+// CHECK-LABEL: entry:
+// CHECK-NEXT: [[RETVAL:%.*]] = alloca i8*,
+// CHECK-NEXT: [[SELFADDR:%.*]] = alloca %0*,
+// CHECK-NEXT: [[CMDVAL:%_cmd]] = alloca i8*,
+// CHECK-LABEL: objc_direct_method.cont:
+// CHECK: [[CMD:%.*]] = load i8*, i8** [[CMDVAL]],
+// CHECK: call i8* @objc_getProperty({{.*}}, i8*{{.*}} [[CMD]], {{.*}})
+
 @interface Foo : Root {
   id __strong _cause_cxx_destruct;
 }
Index: clang/lib/CodeGen/CGObjC.cpp
===================================================================
--- clang/lib/CodeGen/CGObjC.cpp
+++ clang/lib/CodeGen/CGObjC.cpp
@@ -1189,8 +1189,15 @@
     // 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");
+    if (getterMethod->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.
+      EmitVarDecl(*getterMethod->getCmdDecl());
+    }
+    llvm::Value *cmd = Builder.CreateLoad(GetAddrOfLocalVar(getterMethod->getCmdDecl()),
+                             "cmd");
     llvm::Value *self = Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
     llvm::Value *ivarOffset =
       EmitIvarOffset(classImpl->getClassInterface(), ivar);
@@ -1475,10 +1482,16 @@
 
     // Emit objc_setProperty((id) self, _cmd, offset, arg,
     //                       <is-atomic>, <is-copy>).
-    llvm::Value *cmd =
-      Builder.CreateLoad(GetAddrOfLocalVar(setterMethod->getCmdDecl()));
-    llvm::Value *self =
-      Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
+    if (setterMethod->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.
+      EmitVarDecl(*setterMethod->getCmdDecl());
+    }
+    llvm::Value *cmd = Builder.CreateLoad(GetAddrOfLocalVar(setterMethod->getCmdDecl()),
+                               "cmd");
+    llvm::Value *self = Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
     llvm::Value *ivarOffset =
       EmitIvarOffset(classImpl->getClassInterface(), ivar);
     Address argAddr = GetAddrOfLocalVar(*setterMethod->param_begin());


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