diff --git a/lib/Transforms/ObjCARC/DependencyAnalysis.cpp b/lib/Transforms/ObjCARC/DependencyAnalysis.cpp index 5aada9c3734..8f917aeb372 100644 --- a/lib/Transforms/ObjCARC/DependencyAnalysis.cpp +++ b/lib/Transforms/ObjCARC/DependencyAnalysis.cpp @@ -38,6 +38,7 @@ llvm::objcarc::CanAlterRefCount(const Instruction *Inst, const Value *Ptr, switch (Class) { case IC_Autorelease: case IC_AutoreleaseRV: + case IC_IntrinsicUser: case IC_User: // These operations never directly modify a reference count. return false; diff --git a/lib/Transforms/ObjCARC/ObjCARC.h b/lib/Transforms/ObjCARC/ObjCARC.h index e062b665554..61602260be3 100644 --- a/lib/Transforms/ObjCARC/ObjCARC.h +++ b/lib/Transforms/ObjCARC/ObjCARC.h @@ -89,6 +89,7 @@ enum InstructionClass { IC_CopyWeak, ///< objc_copyWeak (derived) IC_DestroyWeak, ///< objc_destroyWeak (derived) IC_StoreStrong, ///< objc_storeStrong (derived) + IC_IntrinsicUser, ///< clang.arc.use IC_CallOrUser, ///< could call objc_release and/or "use" pointers IC_Call, ///< could call objc_release IC_User, ///< could "use" a pointer @@ -97,6 +98,13 @@ enum InstructionClass { raw_ostream &operator<<(raw_ostream &OS, const InstructionClass Class); +/// \brief Test if the given class is a kind of user. +inline static bool IsUser(InstructionClass Class) { + return Class == IC_User || + Class == IC_CallOrUser || + Class == IC_IntrinsicUser; +} + /// \brief Test if the given class is objc_retain or equivalent. static inline bool IsRetain(InstructionClass Class) { return Class == IC_Retain || diff --git a/lib/Transforms/ObjCARC/ObjCARCContract.cpp b/lib/Transforms/ObjCARC/ObjCARCContract.cpp index 1c13d1cbea4..5d0865e8bea 100644 --- a/lib/Transforms/ObjCARC/ObjCARCContract.cpp +++ b/lib/Transforms/ObjCARC/ObjCARCContract.cpp @@ -453,6 +453,10 @@ bool ObjCARCContract::runOnFunction(Function &F) { if (isa(Inst)) TailOkForStoreStrongs = false; continue; + case IC_IntrinsicUser: + // Remove calls to @clang.arc.use(...). + Inst->eraseFromParent(); + continue; default: continue; } diff --git a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp index 9c14949877f..0410b3bb79a 100644 --- a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp +++ b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp @@ -211,6 +211,9 @@ static bool DoesRetainableObjPtrEscape(const User *Ptr) { // These special functions make copies of their pointer arguments. return true; } + case IC_IntrinsicUser: + // Use by the use intrinsic is not an escape. + continue; case IC_User: case IC_None: // Use by an instruction which copies the value is an escape if the @@ -1601,8 +1604,7 @@ ObjCARCOpt::VisitInstructionBottomUp(Instruction *Inst, else S.RRI.ReverseInsertPts.insert(llvm::next(BasicBlock::iterator(Inst))); S.SetSeq(S_Use); - } else if (Seq == S_Release && - (Class == IC_User || Class == IC_CallOrUser)) { + } else if (Seq == S_Release && IsUser(Class)) { // Non-movable releases depend on any possible objc pointer use. S.SetSeq(S_Stop); assert(S.RRI.ReverseInsertPts.empty()); @@ -2392,6 +2394,7 @@ void ObjCARCOpt::OptimizeWeakCalls(Function &F) { goto clobbered; case IC_AutoreleasepoolPush: case IC_None: + case IC_IntrinsicUser: case IC_User: // Weak pointers are only modified through the weak entry points // (and arbitrary calls, which could call the weak entry points). diff --git a/lib/Transforms/ObjCARC/ObjCARCUtil.cpp b/lib/Transforms/ObjCARC/ObjCARCUtil.cpp index a841c64a9f5..0a54451bb17 100644 --- a/lib/Transforms/ObjCARC/ObjCARCUtil.cpp +++ b/lib/Transforms/ObjCARC/ObjCARCUtil.cpp @@ -72,6 +72,8 @@ raw_ostream &llvm::objcarc::operator<<(raw_ostream &OS, return OS << "IC_Call"; case IC_User: return OS << "IC_User"; + case IC_IntrinsicUser: + return OS << "IC_IntrinsicUser"; case IC_None: return OS << "IC_None"; } @@ -81,10 +83,11 @@ raw_ostream &llvm::objcarc::operator<<(raw_ostream &OS, InstructionClass llvm::objcarc::GetFunctionClass(const Function *F) { Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end(); - // No arguments. + // No (mandatory) arguments. if (AI == AE) return StringSwitch(F->getName()) .Case("objc_autoreleasePoolPush", IC_AutoreleasepoolPush) + .Case("clang.arc.use", IC_IntrinsicUser) .Default(IC_CallOrUser); // One argument. diff --git a/test/Transforms/ObjCARC/contract.ll b/test/Transforms/ObjCARC/contract.ll index b6fba596034..0b60683d999 100644 --- a/test/Transforms/ObjCARC/contract.ll +++ b/test/Transforms/ObjCARC/contract.ll @@ -162,4 +162,15 @@ return: ; preds = %if.then, %entry ret i8* %retval } +; Kill calls to @clang.arc.use(...) +; CHECK: define void @test9( +; CHECK-NOT: clang.arc.use +; CHECK: } +define void @test9(i8* %a, i8* %b) { + call void (...)* @clang.arc.use(i8* %a, i8* %b) nounwind + ret void +} + +declare void @clang.arc.use(...) nounwind + ; CHECK: attributes [[NUW]] = { nounwind }