llvm · plotfi · Dec 30, 2023
diff --git a/clang/include/clang/AST/DeclObjC.h b/clang/include/clang/AST/DeclObjC.h
@@ -482,6 +482,20 @@ class ObjCMethodDecl : public NamedDecl, public DeclContext {
   /// True if the method is tagged as objc_direct
   bool isDirectMethod() const;
 
+  /// True if method is meant to be visible.
+  ///
+  /// TODO: For now this is only true for a very narrow case where the method
+  /// must be direct and must also be explicitly marked as
+  /// __attribute__((visibility("default"))). In the future it may be possible
+  /// to assume that all direct (or even both direct and indirect) methods are
+  /// visible but for the time being it is prudent to provide this default
+  /// visibility behavior as an opt-in only.
+  bool hasMethodVisibilityDefault() const {
+    return isDirectMethod() &&
+           getExplicitVisibility(VisibilityForValue)
+                   .value_or(HiddenVisibility) == DefaultVisibility;
+  }
+
   /// True if the method has a parameter that's destroyed in the callee.
   bool hasParamDestroyedInCallee() const;
 

diff --git a/clang/lib/AST/Mangle.cpp b/clang/lib/AST/Mangle.cpp
@@ -363,10 +363,16 @@ void MangleContext::mangleObjCMethodName(const ObjCMethodDecl *MD,
   }
 
   // \01+[ContainerName(CategoryName) SelectorName]
+  // Note: If we are mangling for an objc_direct method with external visibility
+  //       then the standard mangling scheme will not work. We must replace the
+  //       square braces with angle braces so in the case of visible direct objc
+  //       methods it results in: +<ContainerName(CategoryName) SelectorName>
+  //       This will include a prefix _ on Darwin.
   if (includePrefixByte) {
     OS << '\01';
   }
-  OS << (MD->isInstanceMethod() ? '-' : '+') << '[';
+  OS << (MD->isInstanceMethod() ? '-' : '+');
+  OS << (MD->hasMethodVisibilityDefault() ? '<' : '[');
   if (const auto *CID = MD->getCategory()) {
     OS << CID->getClassInterface()->getName();
     if (includeCategoryNamespace) {
@@ -380,7 +386,7 @@ void MangleContext::mangleObjCMethodName(const ObjCMethodDecl *MD,
   }
   OS << ' ';
   MD->getSelector().print(OS);
-  OS << ']';
+  OS << (MD->hasMethodVisibilityDefault() ? '>' : ']');
 }
 
 void MangleContext::mangleObjCMethodNameAsSourceName(const ObjCMethodDecl *MD,

diff --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
@@ -761,7 +761,9 @@ void CodeGenFunction::StartObjCMethod(const ObjCMethodDecl *OMD,
 
   const CGFunctionInfo &FI = CGM.getTypes().arrangeObjCMethodDeclaration(OMD);
   if (OMD->isDirectMethod()) {
-    Fn->setVisibility(llvm::Function::HiddenVisibility);
+    Fn->setVisibility(OMD->hasMethodVisibilityDefault()
+                          ? llvm::Function::DefaultVisibility
+                          : llvm::Function::HiddenVisibility);
     CGM.SetLLVMFunctionAttributes(OMD, FI, Fn, /*IsThunk=*/false);
     CGM.SetLLVMFunctionAttributesForDefinition(OMD, Fn);
   } else {

diff --git a/clang/lib/CodeGen/CGObjCRuntime.cpp b/clang/lib/CodeGen/CGObjCRuntime.cpp
@@ -470,8 +470,9 @@ std::string CGObjCRuntime::getSymbolNameForMethod(const ObjCMethodDecl *OMD,
                                                   bool includeCategoryName) {
   std::string buffer;
   llvm::raw_string_ostream out(buffer);
-  CGM.getCXXABI().getMangleContext().mangleObjCMethodName(OMD, out,
-                                       /*includePrefixByte=*/true,
-                                       includeCategoryName);
+  CGM.getCXXABI().getMangleContext().mangleObjCMethodName(
+      OMD, out,
+      /*includePrefixByte=*/
+      !OMD->hasMethodVisibilityDefault(), includeCategoryName);
   return buffer;
 }
diff --git a/clang/test/CodeGenObjC/objc-direct-wrapper.m b/clang/test/CodeGenObjC/objc-direct-wrapper.m
@@ -0,0 +1,86 @@
+// RUN: %clang -fobjc-arc -Wno-objc-root-class -ObjC -fobjc-runtime=ios -FFoundation \
+// RUN: -DENABLE_VISIBLE_OBJC_DIRECT=1 \
+// RUN: -target x86_64-apple-macosx10.15.0 -c -o - %s | \
+// RUN: llvm-nm - | FileCheck -check-prefix=CHECK-WRAPPER %s
+
+// RUN: %clang -fobjc-arc -Wno-objc-root-class \
+// RUN: -target x86_64-apple-macosx10.15.0 \
+// RUN: -ObjC -fobjc-runtime=ios -FFoundation -c -o - %s | llvm-nm - | \
+// RUN: FileCheck -check-prefix=CHECK-DEFAULT %s
+
+// RUN: %clang -fobjc-arc -Wno-objc-root-class \
+// RUN: -DENABLE_VISIBLE_OBJC_DIRECT=1 \
+// RUN: -target x86_64-apple-macosx10.15.0 \
+// RUN: -ObjC -fobjc-runtime=ios -FFoundation -c -o - %s -S -emit-llvm | \
+// RUN: FileCheck -check-prefix=CHECK-WRAPPER-IR-DEF %s
+
+// RUN: %clang -fobjc-arc -Wno-objc-root-class -DNO_OBJC_IMPL \
+// RUN: -DENABLE_VISIBLE_OBJC_DIRECT=1 \
+// RUN: -target x86_64-apple-macosx10.15.0 \
+// RUN: -ObjC -fobjc-runtime=ios -FFoundation -c -o - %s -S -emit-llvm | \
+// RUN: FileCheck -check-prefix=CHECK-WRAPPER-IR-DECLARE %s
+
+// RUN: not %clang -fobjc-arc -Wno-objc-root-class -DENABLE_PROTOCOL_DIRECT_FAIL \
+// RUN: -DENABLE_VISIBLE_OBJC_DIRECT=1 \
+// RUN: -target x86_64-apple-macosx10.15.0 \
+// RUN: -ObjC -fobjc-runtime=ios -FFoundation -c -o - %s -S -emit-llvm 2>&1 | \
+// RUN: FileCheck -check-prefix=CHECK-PROTOCOL-DIRECT-FAIL %s
+
+////////////////////////////////////////////////////////////////////////////////
+
+// RUN: %clang -fobjc-arc -Wno-objc-root-class -ObjC -fobjc-runtime=ios -FFoundation \
+// RUN: -DENABLE_VISIBLE_OBJC_DIRECT=0 \
+// RUN: -target x86_64-apple-macosx10.15.0 -c -o - %s | \
+// RUN: llvm-nm - | FileCheck -check-prefix=CHECK-WRAPPER-INDIRECT %s
+
+// RUN: %clang -fobjc-arc -Wno-objc-root-class \
+// RUN: -DENABLE_VISIBLE_OBJC_DIRECT=0 \
+// RUN: -target x86_64-apple-macosx10.15.0 \
+// RUN: -ObjC -fobjc-runtime=ios -FFoundation -c -o - %s -S -emit-llvm | \
+// RUN: FileCheck -check-prefix=CHECK-WRAPPER-IR-DEF-INDIRECT %s
+
+// RUN: %clang -fobjc-arc -Wno-objc-root-class -DNO_OBJC_IMPL \
+// RUN: -DENABLE_VISIBLE_OBJC_DIRECT=0 \
+// RUN: -target x86_64-apple-macosx10.15.0 \
+// RUN: -ObjC -fobjc-runtime=ios -FFoundation -c -o - %s -S -emit-llvm | \
+// RUN: FileCheck -check-prefix=CHECK-WRAPPER-IR-DECLARE-INDIRECT %s
+
+// CHECK-WRAPPER: T _-<C testMethod:bar:>
+         // TODO: Fix this
+// CHECK-DEFAULT: t -[C testMethod:bar:]
+// CHECK-WRAPPER-IR-DEF: define {{(dso_local )?}}void @"-<C testMethod:bar:>"
+// CHECK-WRAPPER-IR-DECLARE: declare {{(dso_local )?}}void @"-<C testMethod:bar:>"
+// CHECK-PROTOCOL-DIRECT-FAIL: error: 'objc_direct' attribute cannot be applied to methods declared in an Objective-C protocol
+
+// CHECK-WRAPPER-INDIRECT-NOT: T _-<C testMethod:bar:>
+// CHECK-WRAPPER-IR-DEF-INDIRECT-NOT: define {{(dso_local )?}}void @"-<C testMethod:bar:>"
+// CHECK-WRAPPER-IR-DECLARE-INDIRECT-NOT: declare {{(dso_local )?}}void @"-<C testMethod:bar:>"
+
+#if ENABLE_VISIBLE_OBJC_DIRECT
+#define OBJC_DIRECT __attribute__((objc_direct)) __attribute__((visibility("default")))
+#else
+#define OBJC_DIRECT
+#endif
+
+@interface C
+- (void)testMethod:(int)arg1 bar:(float)arg2 OBJC_DIRECT;
+@end
+
+#ifndef NO_OBJC_IMPL
+@implementation C
+- (void)testMethod:(int)arg1 bar:(float)arg2 OBJC_DIRECT {
+}
+@end
+#endif
+
+#ifdef ENABLE_PROTOCOL_DIRECT_FAIL
+@protocol ProtoDirectVisibleFail
+- (void)protoMethod OBJC_DIRECT;      // expected-error {{'objc_direct' attribute cannot be applied to methods declared in an Objective-C protocol}}
+@end
+#endif
+
+C *c;
+
+void f() {
+  [c testMethod:1 bar:1.0];
+}