aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/llvm16/lib/Transforms/ObjCARC/ObjCARC.h
blob: d4570ff908f169edc5fb4d63efd6844bc5c80afc (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
//===- ObjCARC.h - ObjC ARC Optimization --------------*- C++ -*-----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
/// \file
/// This file defines common definitions/declarations used by the ObjC ARC
/// Optimizer. ARC stands for Automatic Reference Counting and is a system for
/// managing reference counts for objects in Objective C.
///
/// WARNING: This file knows about certain library functions. It recognizes them
/// by name, and hardwires knowledge of their semantics.
///
/// WARNING: This file knows about how certain Objective-C library functions are
/// used. Naive LLVM IR transformations which would otherwise be
/// behavior-preserving may break these assumptions.
///
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARC_H
#define LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARC_H

#include "llvm/Analysis/EHPersonalities.h"
#include "llvm/Analysis/ObjCARCAnalysisUtils.h"
#include "llvm/Analysis/ObjCARCUtil.h"
#include "llvm/Transforms/Utils/Local.h"

namespace llvm {
namespace objcarc {

/// Erase the given instruction.
///
/// Many ObjC calls return their argument verbatim,
/// so if it's such a call and the return value has users, replace them with the
/// argument value.
///
static inline void EraseInstruction(Instruction *CI) {
  Value *OldArg = cast<CallInst>(CI)->getArgOperand(0);

  bool Unused = CI->use_empty();

  if (!Unused) {
    // Replace the return value with the argument.
    assert((IsForwarding(GetBasicARCInstKind(CI)) ||
            (IsNoopOnNull(GetBasicARCInstKind(CI)) &&
             IsNullOrUndef(OldArg->stripPointerCasts()))) &&
           "Can't delete non-forwarding instruction with users!");
    CI->replaceAllUsesWith(OldArg);
  }

  CI->eraseFromParent();

  if (Unused)
    RecursivelyDeleteTriviallyDeadInstructions(OldArg);
}

/// If Inst is a ReturnRV and its operand is a call or invoke, return the
/// operand. Otherwise return null.
static inline const Instruction *getreturnRVOperand(const Instruction &Inst,
                                                    ARCInstKind Class) {
  if (Class != ARCInstKind::RetainRV)
    return nullptr;

  const auto *Opnd = Inst.getOperand(0)->stripPointerCasts();
  if (const auto *C = dyn_cast<CallInst>(Opnd))
    return C;
  return dyn_cast<InvokeInst>(Opnd);
}

/// Return the list of PHI nodes that are equivalent to PN.
template<class PHINodeTy, class VectorTy>
void getEquivalentPHIs(PHINodeTy &PN, VectorTy &PHIList) {
  auto *BB = PN.getParent();
  for (auto &P : BB->phis()) {
    if (&P == &PN) // Do not add PN to the list.
      continue;
    unsigned I = 0, E = PN.getNumIncomingValues();
    for (; I < E; ++I) {
      auto *BB = PN.getIncomingBlock(I);
      auto *PNOpnd = PN.getIncomingValue(I)->stripPointerCasts();
      auto *POpnd = P.getIncomingValueForBlock(BB)->stripPointerCasts();
      if (PNOpnd != POpnd)
        break;
    }
    if (I == E)
      PHIList.push_back(&P);
  }
}

static inline MDString *getRVInstMarker(Module &M) {
  const char *MarkerKey = getRVMarkerModuleFlagStr();
  return dyn_cast_or_null<MDString>(M.getModuleFlag(MarkerKey));
}

/// Create a call instruction with the correct funclet token. This should be
/// called instead of calling CallInst::Create directly unless the call is
/// going to be removed from the IR before WinEHPrepare.
CallInst *createCallInstWithColors(
    FunctionCallee Func, ArrayRef<Value *> Args, const Twine &NameStr,
    Instruction *InsertBefore,
    const DenseMap<BasicBlock *, ColorVector> &BlockColors);

class BundledRetainClaimRVs {
public:
  BundledRetainClaimRVs(bool ContractPass) : ContractPass(ContractPass) {}
  ~BundledRetainClaimRVs();

  /// Insert a retainRV/claimRV call to the normal destination blocks of invokes
  /// with operand bundle "clang.arc.attachedcall". If the edge to the normal
  /// destination block is a critical edge, split it.
  std::pair<bool, bool> insertAfterInvokes(Function &F, DominatorTree *DT);

  /// Insert a retainRV/claimRV call.
  CallInst *insertRVCall(Instruction *InsertPt, CallBase *AnnotatedCall);

  /// Insert a retainRV/claimRV call with colors.
  CallInst *insertRVCallWithColors(
      Instruction *InsertPt, CallBase *AnnotatedCall,
      const DenseMap<BasicBlock *, ColorVector> &BlockColors);

  /// See if an instruction is a bundled retainRV/claimRV call.
  bool contains(const Instruction *I) const {
    if (auto *CI = dyn_cast<CallInst>(I))
      return RVCalls.count(CI);
    return false;
  }

  /// Remove a retainRV/claimRV call entirely.
  void eraseInst(CallInst *CI) {
    auto It = RVCalls.find(CI);
    if (It != RVCalls.end()) {
      // Remove call to @llvm.objc.clang.arc.noop.use.
      for (User *U : It->second->users())
        if (auto *CI = dyn_cast<CallInst>(U))
          if (CI->getIntrinsicID() == Intrinsic::objc_clang_arc_noop_use) {
            CI->eraseFromParent();
            break;
          }

      auto *NewCall = CallBase::removeOperandBundle(
          It->second, LLVMContext::OB_clang_arc_attachedcall, It->second);
      NewCall->copyMetadata(*It->second);
      It->second->replaceAllUsesWith(NewCall);
      It->second->eraseFromParent();
      RVCalls.erase(It);
    }
    EraseInstruction(CI);
  }

private:
  /// A map of inserted retainRV/claimRV calls to annotated calls/invokes.
  DenseMap<CallInst *, CallBase *> RVCalls;

  bool ContractPass;
};

} // end namespace objcarc
} // end namespace llvm

#endif