diff options
| -rw-r--r-- | lib/CodeGen/CGObjCMac.cpp | 29 | ||||
| -rw-r--r-- | test/CodeGenObjC/ivar-invariant.m | 53 |
2 files changed, 78 insertions, 4 deletions
diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp index b61852765a..bf02439ec6 100644 --- a/lib/CodeGen/CGObjCMac.cpp +++ b/lib/CodeGen/CGObjCMac.cpp @@ -1432,6 +1432,25 @@ private: /// class implementation is "non-lazy". bool ImplementationIsNonLazy(const ObjCImplDecl *OD) const; + bool IsIvarOffsetKnownIdempotent(const CodeGen::CodeGenFunction &CGF, + const ObjCInterfaceDecl *ID, + const ObjCIvarDecl *IV) { + // Annotate the load as an invariant load iff the object type is the type, + // or a derived type, of the class containing the ivar within an ObjC + // method. This check is needed because the ivar offset is a lazily + // initialised value that may depend on objc_msgSend to perform a fixup on + // the first message dispatch. + // + // An additional opportunity to mark the load as invariant arises when the + // base of the ivar access is a parameter to an Objective C method. + // However, because the parameters are not available in the current + // interface, we cannot perform this check. + if (dyn_cast<ObjCMethodDecl>(CGF.CurFuncDecl)) + if (IV->getContainingInterface()->isSuperClassOf(ID)) + return true; + return false; + } + public: CGObjCNonFragileABIMac(CodeGen::CodeGenModule &cgm); // FIXME. All stubs for now! @@ -6449,10 +6468,12 @@ LValue CGObjCNonFragileABIMac::EmitObjCValueForIvar( unsigned CVRQualifiers) { ObjCInterfaceDecl *ID = ObjectTy->getAs<ObjCObjectType>()->getInterface(); llvm::Value *Offset = EmitIvarOffset(CGF, ID, Ivar); - if (llvm::LoadInst *LI = dyn_cast<llvm::LoadInst>(Offset)) - LI->setMetadata(CGM.getModule().getMDKindID("invariant.load"), - llvm::MDNode::get(VMContext, - ArrayRef<llvm::Value*>())); + + if (IsIvarOffsetKnownIdempotent(CGF, ID, Ivar)) + if (llvm::LoadInst *LI = cast<llvm::LoadInst>(Offset)) + LI->setMetadata(CGM.getModule().getMDKindID("invariant.load"), + llvm::MDNode::get(VMContext, ArrayRef<llvm::Value*>())); + return EmitValueForIvarAtOffset(CGF, ID, BaseValue, Ivar, CVRQualifiers, Offset); } diff --git a/test/CodeGenObjC/ivar-invariant.m b/test/CodeGenObjC/ivar-invariant.m new file mode 100644 index 0000000000..f59265445b --- /dev/null +++ b/test/CodeGenObjC/ivar-invariant.m @@ -0,0 +1,53 @@ +// RUN: %clang_cc1 -triple x86_64-apple-darwin -x objective-c %s -o - | FileCheck %s + +@interface NSObject ++ (id) new; +- (id) init; +@end + +@interface Base : NSObject @end + +// @implementation Base +// { +// int dummy; +// } +// @end + +@interface Derived : Base +{ + @public int member; +} +@end + +@implementation Derived +- (id) init +{ + self = [super init]; + member = 42; + return self; +} +@end + +// CHECK: [[IVAR:%.*]] = load i64* @"OBJC_IVAR_$_Derived.member", !invariant.load + +void * variant_load_1(int i) { + void *ptr; + while (i--) { + Derived *d = [Derived new]; + ptr = &d->member; + } + return ptr; +} + +// CHECK: [[IVAR:%.*]] = load i64* @"OBJC_IVAR_$_Derived.member"{{$}} + +@interface Container : Derived @end +@implementation Container +- (void *) invariant_load_1 +{ + return &self->member; +} +@end + +// CHECK: [[IVAR:%.*]] = load i64* @"OBJC_IVAR_$_Derived.member", !invariant.load + |