[PATCH] D113455: [clang][objc][codegen] Skip emitting ObjC category metadata when the category is empty

[Josh Learn via Phabricator via cfe-commits]

guitard0g updated this revision to Diff 386943.
guitard0g added a comment.

Address comments and fix fragile test to use -O0 and -disable-llvm-passes.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D113455/new/

https://reviews.llvm.org/D113455

Files:
  clang/lib/CodeGen/CGObjCMac.cpp
  clang/test/CodeGenObjC/category-class-empty.m
  clang/test/CodeGenObjC/non-lazy-classes.m


Index: clang/test/CodeGenObjC/non-lazy-classes.m
===================================================================
--- clang/test/CodeGenObjC/non-lazy-classes.m
+++ clang/test/CodeGenObjC/non-lazy-classes.m
@@ -42,4 +42,7 @@
 @implementation E @end
 
 __attribute__((objc_nonlazy_class))
-@implementation E (MyCat) @end
+@implementation E (MyCat)
+-(void) load {
+}
+@end
Index: clang/test/CodeGenObjC/category-class-empty.m
===================================================================
--- /dev/null
+++ clang/test/CodeGenObjC/category-class-empty.m
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -triple i386-apple-darwin9 -O0 -disable-llvm-passes -emit-llvm -o - %s | FileCheck %s
+// PR7431
+
+// CHECK-NOT: @"OBJC_LABEL_CATEGORY_$" = private global [1 x i8*] [i8* bitcast (%struct._category_t* @"_OBJC_$_CATEGORY_A_$_foo"
+
+@interface A
+@end
+__attribute__((objc_direct_members))
+@interface A(foo)
+- (void)foo_myStuff;
+@end
+@implementation A(foo)
+- (void)foo_myStuff {
+}
+@end
+
Index: clang/lib/CodeGen/CGObjCMac.cpp
===================================================================
--- clang/lib/CodeGen/CGObjCMac.cpp
+++ clang/lib/CodeGen/CGObjCMac.cpp
@@ -6672,46 +6672,62 @@
     }
   }
 
-  values.add(emitMethodList(listName, MethodListType::CategoryInstanceMethods,
-                            instanceMethods));
-  values.add(emitMethodList(listName, MethodListType::CategoryClassMethods,
-                            classMethods));
+  auto instanceMethodList = emitMethodList(
+      listName, MethodListType::CategoryInstanceMethods, instanceMethods);
+  auto classMethodList = emitMethodList(
+      listName, MethodListType::CategoryClassMethods, classMethods);
+  values.add(instanceMethodList);
+  values.add(classMethodList);
+  // Keep track of whether we have actual metadata to emit.
+  bool isEmptyCategory =
+      instanceMethodList->isNullValue() && classMethodList->isNullValue();
 
   const ObjCCategoryDecl *Category =
-    Interface->FindCategoryDeclaration(OCD->getIdentifier());
+      Interface->FindCategoryDeclaration(OCD->getIdentifier());
   if (Category) {
     SmallString<256> ExtName;
-    llvm::raw_svector_ostream(ExtName) << Interface->getObjCRuntimeNameAsString() << "_$_"
-                                       << OCD->getName();
-    values.add(EmitProtocolList("_OBJC_CATEGORY_PROTOCOLS_$_"
-                                   + Interface->getObjCRuntimeNameAsString() + "_$_"
-                                   + Category->getName(),
-                                Category->protocol_begin(),
-                                Category->protocol_end()));
-    values.add(EmitPropertyList("_OBJC_$_PROP_LIST_" + ExtName.str(),
-                                OCD, Category, ObjCTypes, false));
-    values.add(EmitPropertyList("_OBJC_$_CLASS_PROP_LIST_" + ExtName.str(),
-                                OCD, Category, ObjCTypes, true));
+    llvm::raw_svector_ostream(ExtName)
+        << Interface->getObjCRuntimeNameAsString() << "_$_" << OCD->getName();
+    auto protocolList =
+        EmitProtocolList("_OBJC_CATEGORY_PROTOCOLS_$_" +
+                             Interface->getObjCRuntimeNameAsString() + "_$_" +
+                             Category->getName(),
+                         Category->protocol_begin(), Category->protocol_end());
+    auto propertyList = EmitPropertyList("_OBJC_$_PROP_LIST_" + ExtName.str(),
+                                         OCD, Category, ObjCTypes, false);
+    auto classPropertyList =
+        EmitPropertyList("_OBJC_$_CLASS_PROP_LIST_" + ExtName.str(), OCD,
+                         Category, ObjCTypes, true);
+    values.add(protocolList);
+    values.add(propertyList);
+    values.add(classPropertyList);
+    isEmptyCategory &= protocolList->isNullValue() &&
+                       propertyList->isNullValue() &&
+                       classPropertyList->isNullValue();
   } else {
     values.addNullPointer(ObjCTypes.ProtocolListnfABIPtrTy);
     values.addNullPointer(ObjCTypes.PropertyListPtrTy);
     values.addNullPointer(ObjCTypes.PropertyListPtrTy);
   }
 
-  unsigned Size = CGM.getDataLayout().getTypeAllocSize(ObjCTypes.CategorynfABITy);
+  unsigned Size =
+      CGM.getDataLayout().getTypeAllocSize(ObjCTypes.CategorynfABITy);
   values.addInt(ObjCTypes.IntTy, Size);
 
   llvm::GlobalVariable *GCATV =
       finishAndCreateGlobal(values, ExtCatName.str(), CGM);
-  CGM.addCompilerUsedGlobal(GCATV);
-  if (Interface->hasAttr<ObjCClassStubAttr>())
-    DefinedStubCategories.push_back(GCATV);
-  else
-    DefinedCategories.push_back(GCATV);
 
-  // Determine if this category is also "non-lazy".
-  if (ImplementationIsNonLazy(OCD))
-    DefinedNonLazyCategories.push_back(GCATV);
+  if (!isEmptyCategory) {
+    CGM.addCompilerUsedGlobal(GCATV);
+    if (Interface->hasAttr<ObjCClassStubAttr>())
+      DefinedStubCategories.push_back(GCATV);
+    else
+      DefinedCategories.push_back(GCATV);
+
+    // Determine if this category is also "non-lazy".
+    if (ImplementationIsNonLazy(OCD))
+      DefinedNonLazyCategories.push_back(GCATV);
+  }
   // method definition entries must be clear for next implementation.
   MethodDefinitions.clear();
 }

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