include/llvm/Analysis/ObjCARCInstKind.h

   1 //===- ObjCARCInstKind.h - ARC instruction equivalence classes --*- 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
   9 #ifndef LLVM_ANALYSIS_OBJCARCINSTKIND_H
  10 #define LLVM_ANALYSIS_OBJCARCINSTKIND_H
  11
  12 #include "llvm/IR/Function.h"
  13 #include "llvm/IR/Intrinsics.h"
  14 #include "llvm/IR/Instructions.h"
  15
  16 namespace llvm {
  17 namespace objcarc {
  18
  19 /// \enum ARCInstKind
  20 ///
  21 /// Equivalence classes of instructions in the ARC Model.
  22 ///
  23 /// Since we do not have "instructions" to represent ARC concepts in LLVM IR,
  24 /// we instead operate on equivalence classes of instructions.
  25 ///
  26 /// TODO: This should be split into two enums: a runtime entry point enum
  27 /// (possibly united with the ARCRuntimeEntrypoint class) and an enum that deals
  28 /// with effects of instructions in the ARC model (which would handle the notion
  29 /// of a User or CallOrUser).
  30 enum class ARCInstKind {
  31   Retain,                   ///< objc_retain
  32   RetainRV,                 ///< objc_retainAutoreleasedReturnValue
  33   ClaimRV,                  ///< objc_unsafeClaimAutoreleasedReturnValue
  34   RetainBlock,              ///< objc_retainBlock
  35   Release,                  ///< objc_release
  36   Autorelease,              ///< objc_autorelease
  37   AutoreleaseRV,            ///< objc_autoreleaseReturnValue
  38   AutoreleasepoolPush,      ///< objc_autoreleasePoolPush
  39   AutoreleasepoolPop,       ///< objc_autoreleasePoolPop
  40   NoopCast,                 ///< objc_retainedObject, etc.
  41   FusedRetainAutorelease,   ///< objc_retainAutorelease
  42   FusedRetainAutoreleaseRV, ///< objc_retainAutoreleaseReturnValue
  43   LoadWeakRetained,         ///< objc_loadWeakRetained (primitive)
  44   StoreWeak,                ///< objc_storeWeak (primitive)
  45   InitWeak,                 ///< objc_initWeak (derived)
  46   LoadWeak,                 ///< objc_loadWeak (derived)
  47   MoveWeak,                 ///< objc_moveWeak (derived)
  48   CopyWeak,                 ///< objc_copyWeak (derived)
  49   DestroyWeak,              ///< objc_destroyWeak (derived)
  50   StoreStrong,              ///< objc_storeStrong (derived)
  51   IntrinsicUser,            ///< llvm.objc.clang.arc.use
  52   CallOrUser,               ///< could call objc_release and/or "use" pointers
  53   Call,                     ///< could call objc_release
  54   User,                     ///< could "use" a pointer
  55   None                      ///< anything that is inert from an ARC perspective.
  56 };
  57
  58 raw_ostream &operator<<(raw_ostream &OS, const ARCInstKind Class);
  59
  60 /// Test if the given class is a kind of user.
  61 bool IsUser(ARCInstKind Class);
  62
  63 /// Test if the given class is objc_retain or equivalent.
  64 bool IsRetain(ARCInstKind Class);
  65
  66 /// Test if the given class is objc_autorelease or equivalent.
  67 bool IsAutorelease(ARCInstKind Class);
  68
  69 /// Test if the given class represents instructions which return their
  70 /// argument verbatim.
  71 bool IsForwarding(ARCInstKind Class);
  72
  73 /// Test if the given class represents instructions which do nothing if
  74 /// passed a null pointer.
  75 bool IsNoopOnNull(ARCInstKind Class);
  76
  77 /// Test if the given class represents instructions which do nothing if
  78 /// passed a global variable.
  79 bool IsNoopOnGlobal(ARCInstKind Class);
  80
  81 /// Test if the given class represents instructions which are always safe
  82 /// to mark with the "tail" keyword.
  83 bool IsAlwaysTail(ARCInstKind Class);
  84
  85 /// Test if the given class represents instructions which are never safe
  86 /// to mark with the "tail" keyword.
  87 bool IsNeverTail(ARCInstKind Class);
  88
  89 /// Test if the given class represents instructions which are always safe
  90 /// to mark with the nounwind attribute.
  91 bool IsNoThrow(ARCInstKind Class);
  92
  93 /// Test whether the given instruction can autorelease any pointer or cause an
  94 /// autoreleasepool pop.
  95 bool CanInterruptRV(ARCInstKind Class);
  96
  97 /// Determine if F is one of the special known Functions.  If it isn't,
  98 /// return ARCInstKind::CallOrUser.
  99 ARCInstKind GetFunctionClass(const Function *F);
 100
 101 /// Determine which objc runtime call instruction class V belongs to.
 102 ///
 103 /// This is similar to GetARCInstKind except that it only detects objc
 104 /// runtime calls. This allows it to be faster.
 105 ///
 106 inline ARCInstKind GetBasicARCInstKind(const Value *V) {
 107   if (const CallInst *CI = dyn_cast<CallInst>(V)) {
 108     if (const Function *F = CI->getCalledFunction())
 109       return GetFunctionClass(F);
 110     // Otherwise, be conservative.
 111     return ARCInstKind::CallOrUser;
 112   }
 113
 114   // Otherwise, be conservative.
 115   return isa<InvokeInst>(V) ? ARCInstKind::CallOrUser : ARCInstKind::User;
 116 }
 117
 118 /// Map V to its ARCInstKind equivalence class.
 119 ARCInstKind GetARCInstKind(const Value *V);
 120
 121 /// Returns false if conservatively we can prove that any instruction mapped to
 122 /// this kind can not decrement ref counts. Returns true otherwise.
 123 bool CanDecrementRefCount(ARCInstKind Kind);
 124
 125 } // end namespace objcarc
 126 } // end namespace llvm
 127
 128 #endif