llvm-6502/lib/Transforms/ObjCARC/ARCInstKind.h
Michael Gottesman 24ee447d0f [objc-arc] Add the predicate CanDecrementRefCount.
This is different from CanAlterRefCount since CanDecrementRefCount is
attempting to prove specifically whether or not an instruction can
decrement instead of the more general question of whether it can
decrement or increment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229936 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-20 00:02:45 +00:00

124 lines
4.7 KiB
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//===--- ARCInstKind.h - ARC instruction equivalence classes -*- C++ -*----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TRANSFORMS_OBJCARC_ARCINSTKIND_H
#define LLVM_LIB_TRANSFORMS_OBJCARC_ARCINSTKIND_H
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Function.h"
namespace llvm {
namespace objcarc {
/// \enum ARCInstKind
///
/// \brief Equivalence classes of instructions in the ARC Model.
///
/// Since we do not have "instructions" to represent ARC concepts in LLVM IR,
/// we instead operate on equivalence classes of instructions.
///
/// TODO: This should be split into two enums: a runtime entry point enum
/// (possibly united with the ARCRuntimeEntrypoint class) and an enum that deals
/// with effects of instructions in the ARC model (which would handle the notion
/// of a User or CallOrUser).
enum class ARCInstKind {
Retain, ///< objc_retain
RetainRV, ///< objc_retainAutoreleasedReturnValue
RetainBlock, ///< objc_retainBlock
Release, ///< objc_release
Autorelease, ///< objc_autorelease
AutoreleaseRV, ///< objc_autoreleaseReturnValue
AutoreleasepoolPush, ///< objc_autoreleasePoolPush
AutoreleasepoolPop, ///< objc_autoreleasePoolPop
NoopCast, ///< objc_retainedObject, etc.
FusedRetainAutorelease, ///< objc_retainAutorelease
FusedRetainAutoreleaseRV, ///< objc_retainAutoreleaseReturnValue
LoadWeakRetained, ///< objc_loadWeakRetained (primitive)
StoreWeak, ///< objc_storeWeak (primitive)
InitWeak, ///< objc_initWeak (derived)
LoadWeak, ///< objc_loadWeak (derived)
MoveWeak, ///< objc_moveWeak (derived)
CopyWeak, ///< objc_copyWeak (derived)
DestroyWeak, ///< objc_destroyWeak (derived)
StoreStrong, ///< objc_storeStrong (derived)
IntrinsicUser, ///< clang.arc.use
CallOrUser, ///< could call objc_release and/or "use" pointers
Call, ///< could call objc_release
User, ///< could "use" a pointer
None ///< anything that is inert from an ARC perspective.
};
raw_ostream &operator<<(raw_ostream &OS, const ARCInstKind Class);
/// \brief Test if the given class is a kind of user.
bool IsUser(ARCInstKind Class);
/// \brief Test if the given class is objc_retain or equivalent.
bool IsRetain(ARCInstKind Class);
/// \brief Test if the given class is objc_autorelease or equivalent.
bool IsAutorelease(ARCInstKind Class);
/// \brief Test if the given class represents instructions which return their
/// argument verbatim.
bool IsForwarding(ARCInstKind Class);
/// \brief Test if the given class represents instructions which do nothing if
/// passed a null pointer.
bool IsNoopOnNull(ARCInstKind Class);
/// \brief Test if the given class represents instructions which are always safe
/// to mark with the "tail" keyword.
bool IsAlwaysTail(ARCInstKind Class);
/// \brief Test if the given class represents instructions which are never safe
/// to mark with the "tail" keyword.
bool IsNeverTail(ARCInstKind Class);
/// \brief Test if the given class represents instructions which are always safe
/// to mark with the nounwind attribute.
bool IsNoThrow(ARCInstKind Class);
/// Test whether the given instruction can autorelease any pointer or cause an
/// autoreleasepool pop.
bool CanInterruptRV(ARCInstKind Class);
/// \brief Determine if F is one of the special known Functions. If it isn't,
/// return ARCInstKind::CallOrUser.
ARCInstKind GetFunctionClass(const Function *F);
/// \brief Determine which objc runtime call instruction class V belongs to.
///
/// This is similar to GetARCInstKind except that it only detects objc
/// runtime calls. This allows it to be faster.
///
static inline ARCInstKind GetBasicARCInstKind(const Value *V) {
if (const CallInst *CI = dyn_cast<CallInst>(V)) {
if (const Function *F = CI->getCalledFunction())
return GetFunctionClass(F);
// Otherwise, be conservative.
return ARCInstKind::CallOrUser;
}
// Otherwise, be conservative.
return isa<InvokeInst>(V) ? ARCInstKind::CallOrUser : ARCInstKind::User;
}
/// Map V to its ARCInstKind equivalence class.
ARCInstKind GetARCInstKind(const Value *V);
/// Returns false if conservatively we can prove that any instruction mapped to
/// this kind can not decrement ref counts. Returns true otherwise.
bool CanDecrementRefCount(ARCInstKind Kind);
} // end namespace objcarc
} // end namespace llvm
#endif