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Clean up ObjCARCOpts.cpp. NFC.

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I removed unused functions and variables and moved variables closer to
their uses.

llvm-svn: 296218
This commit is contained in:
Akira Hatanaka 2017-02-25 00:53:38 +00:00
parent f6089ca357
commit 7642ff31c9
1 changed files with 7 additions and 81 deletions
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88
lib/Transforms/ObjCARC/ObjCARCOpts.cpp
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@ -85,41 +85,6 @@ static const Value *FindSingleUseIdentifiedObject(const Value *Arg) {
return nullptr;
}
/// This is a wrapper around getUnderlyingObjCPtr along the lines of
/// GetUnderlyingObjects except that it returns early when it sees the first
/// alloca.
static inline bool AreAnyUnderlyingObjectsAnAlloca(const Value *V,
const DataLayout &DL) {
SmallPtrSet<const Value *, 4> Visited;
SmallVector<const Value *, 4> Worklist;
Worklist.push_back(V);
do {
const Value *P = Worklist.pop_back_val();
P = GetUnderlyingObjCPtr(P, DL);
if (isa<AllocaInst>(P))
return true;
if (!Visited.insert(P).second)
continue;
if (const SelectInst *SI = dyn_cast<const SelectInst>(P)) {
Worklist.push_back(SI->getTrueValue());
Worklist.push_back(SI->getFalseValue());
continue;
}
if (const PHINode *PN = dyn_cast<const PHINode>(P)) {
for (Value *IncValue : PN->incoming_values())
Worklist.push_back(IncValue);
continue;
}
} while (!Worklist.empty());
return false;
}
/// @}
///
/// \defgroup ARCOpt ARC Optimization.
@ -481,9 +446,6 @@ namespace {
/// MDKind identifiers.
ARCMDKindCache MDKindCache;
// This is used to track if a pointer is stored into an alloca.
DenseSet<const Value *> MultiOwnersSet;
/// A flag indicating whether this optimization pass should run.
bool Run;
@ -524,8 +486,7 @@ namespace {
PairUpRetainsAndReleases(DenseMap<const BasicBlock *, BBState> &BBStates,
BlotMapVector<Value *, RRInfo> &Retains,
DenseMap<Value *, RRInfo> &Releases, Module *M,
SmallVectorImpl<Instruction *> &NewRetains,
SmallVectorImpl<Instruction *> &NewReleases,
Instruction * Retain,
SmallVectorImpl<Instruction *> &DeadInsts,
RRInfo &RetainsToMove, RRInfo &ReleasesToMove,
Value *Arg, bool KnownSafe,
@ -1155,29 +1116,6 @@ bool ObjCARCOpt::VisitInstructionBottomUp(
case ARCInstKind::None:
// These are irrelevant.
return NestingDetected;
case ARCInstKind::User:
// If we have a store into an alloca of a pointer we are tracking, the
// pointer has multiple owners implying that we must be more conservative.
//
// This comes up in the context of a pointer being ``KnownSafe''. In the
// presence of a block being initialized, the frontend will emit the
// objc_retain on the original pointer and the release on the pointer loaded
// from the alloca. The optimizer will through the provenance analysis
// realize that the two are related, but since we only require KnownSafe in
// one direction, will match the inner retain on the original pointer with
// the guard release on the original pointer. This is fixed by ensuring that
// in the presence of allocas we only unconditionally remove pointers if
// both our retain and our release are KnownSafe.
if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
const DataLayout &DL = BB->getModule()->getDataLayout();
if (AreAnyUnderlyingObjectsAnAlloca(SI->getPointerOperand(), DL)) {
auto I = MyStates.findPtrBottomUpState(
GetRCIdentityRoot(SI->getValueOperand()));
if (I != MyStates.bottom_up_ptr_end())
MultiOwnersSet.insert(I->first);
}
}
break;
default:
break;
}
@ -1540,8 +1478,7 @@ bool ObjCARCOpt::PairUpRetainsAndReleases(
DenseMap<const BasicBlock *, BBState> &BBStates,
BlotMapVector<Value *, RRInfo> &Retains,
DenseMap<Value *, RRInfo> &Releases, Module *M,
SmallVectorImpl<Instruction *> &NewRetains,
SmallVectorImpl<Instruction *> &NewReleases,
Instruction *Retain,
SmallVectorImpl<Instruction *> &DeadInsts, RRInfo &RetainsToMove,
RRInfo &ReleasesToMove, Value *Arg, bool KnownSafe,
bool &AnyPairsCompletelyEliminated) {
@ -1549,7 +1486,6 @@ bool ObjCARCOpt::PairUpRetainsAndReleases(
// is already incremented, we can similarly ignore possible decrements unless
// we are dealing with a retainable object with multiple provenance sources.
bool KnownSafeTD = true, KnownSafeBU = true;
bool MultipleOwners = false;
bool CFGHazardAfflicted = false;
// Connect the dots between the top-down-collected RetainsToMove and
@ -1561,14 +1497,13 @@ bool ObjCARCOpt::PairUpRetainsAndReleases(
unsigned OldCount = 0;
unsigned NewCount = 0;
bool FirstRelease = true;
for (;;) {
for (SmallVector<Instruction *, 4> NewRetains{Retain};;) {
SmallVector<Instruction *, 4> NewReleases;
for (Instruction *NewRetain : NewRetains) {
auto It = Retains.find(NewRetain);
assert(It != Retains.end());
const RRInfo &NewRetainRRI = It->second;
KnownSafeTD &= NewRetainRRI.KnownSafe;
MultipleOwners =
MultipleOwners || MultiOwnersSet.count(GetArgRCIdentityRoot(NewRetain));
for (Instruction *NewRetainRelease : NewRetainRRI.Calls) {
auto Jt = Releases.find(NewRetainRelease);
if (Jt == Releases.end())
@ -1691,7 +1626,6 @@ bool ObjCARCOpt::PairUpRetainsAndReleases(
}
}
}
NewReleases.clear();
if (NewRetains.empty()) break;
}
@ -1745,10 +1679,6 @@ bool ObjCARCOpt::PerformCodePlacement(
DEBUG(dbgs() << "\n== ObjCARCOpt::PerformCodePlacement ==\n");
bool AnyPairsCompletelyEliminated = false;
RRInfo RetainsToMove;
RRInfo ReleasesToMove;
SmallVector<Instruction *, 4> NewRetains;
SmallVector<Instruction *, 4> NewReleases;
SmallVector<Instruction *, 8> DeadInsts;
// Visit each retain.
@ -1780,9 +1710,10 @@ bool ObjCARCOpt::PerformCodePlacement(
// Connect the dots between the top-down-collected RetainsToMove and
// bottom-up-collected ReleasesToMove to form sets of related calls.
NewRetains.push_back(Retain);
RRInfo RetainsToMove, ReleasesToMove;
bool PerformMoveCalls = PairUpRetainsAndReleases(
BBStates, Retains, Releases, M, NewRetains, NewReleases, DeadInsts,
BBStates, Retains, Releases, M, Retain, DeadInsts,
RetainsToMove, ReleasesToMove, Arg, KnownSafe,
AnyPairsCompletelyEliminated);
@ -1794,8 +1725,6 @@ bool ObjCARCOpt::PerformCodePlacement(
}
// Clean up state for next retain.
NewReleases.clear();
NewRetains.clear();
RetainsToMove.clear();
ReleasesToMove.clear();
}
@ -1987,9 +1916,6 @@ bool ObjCARCOpt::OptimizeSequences(Function &F) {
Releases,
F.getParent());
// Cleanup.
MultiOwnersSet.clear();
return AnyPairsCompletelyEliminated && NestingDetected;
}