1 //===- ObjCARCUtil.h - ObjC ARC Utility Functions ---------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 /// \file
9 /// This file defines ARC utility functions which are used by various parts of
10 /// the compiler.
11 ///
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_ANALYSIS_OBJCARCUTIL_H
15 #define LLVM_ANALYSIS_OBJCARCUTIL_H
16 
17 #include "llvm/Analysis/ObjCARCInstKind.h"
18 #include "llvm/IR/Function.h"
19 #include "llvm/IR/InstrTypes.h"
20 #include "llvm/IR/LLVMContext.h"
21 
22 namespace llvm {
23 namespace objcarc {
24 
25 inline const char *getRVMarkerModuleFlagStr() {
26   return "clang.arc.retainAutoreleasedReturnValueMarker";
27 }
28 
29 inline bool hasAttachedCallOpBundle(const CallBase *CB) {
30   // Ignore the bundle if the return type is void. Global optimization passes
31   // can turn the called function's return type to void. That should happen only
32   // if the call doesn't return and the call to @llvm.objc.clang.arc.noop.use
33   // no longer consumes the function return or is deleted. In that case, it's
34   // not necessary to emit the marker instruction or calls to the ARC runtime
35   // functions.
36   return !CB->getFunctionType()->getReturnType()->isVoidTy() &&
37          CB->getOperandBundle(LLVMContext::OB_clang_arc_attachedcall)
38              .has_value();
39 }
40 
41 /// This function returns operand bundle clang_arc_attachedcall's argument,
42 /// which is the address of the ARC runtime function.
43 inline std::optional<Function *> getAttachedARCFunction(const CallBase *CB) {
44   auto B = CB->getOperandBundle(LLVMContext::OB_clang_arc_attachedcall);
45   if (!B)
46     return std::nullopt;
47 
48   return cast<Function>(B->Inputs[0]);
49 }
50 
51 /// Check whether the function is retainRV/unsafeClaimRV.
52 inline bool isRetainOrClaimRV(ARCInstKind Kind) {
53   return Kind == ARCInstKind::RetainRV || Kind == ARCInstKind::UnsafeClaimRV;
54 }
55 
56 /// This function returns the ARCInstKind of the function attached to operand
57 /// bundle clang_arc_attachedcall. It returns std::nullopt if the call doesn't
58 /// have the operand bundle or the operand is null. Otherwise it returns either
59 /// RetainRV or UnsafeClaimRV.
60 inline ARCInstKind getAttachedARCFunctionKind(const CallBase *CB) {
61   std::optional<Function *> Fn = getAttachedARCFunction(CB);
62   if (!Fn)
63     return ARCInstKind::None;
64   auto FnClass = GetFunctionClass(*Fn);
65   assert(isRetainOrClaimRV(FnClass) && "unexpected ARC runtime function");
66   return FnClass;
67 }
68 
69 } // end namespace objcarc
70 } // end namespace llvm
71 
72 #endif
73