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[objc-arc] Remove dead code from previous commit.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189870 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Michael Gottesman 2013-09-03 22:40:56 +00:00
parent 72196ab082
commit be0857051f
1 changed files with 0 additions and 140 deletions
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140
lib/Transforms/ObjCARC/ObjCARCOpts.cpp
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@ -176,91 +176,6 @@ static const Value *FindSingleUseIdentifiedObject(const Value *Arg) {
return 0;
}
/// \brief Test whether the given retainable object pointer escapes.
///
/// This differs from regular escape analysis in that a use as an
/// argument to a call is not considered an escape.
///
static bool DoesRetainableObjPtrEscape(const User *Ptr) {
DEBUG(dbgs() << "DoesRetainableObjPtrEscape: Target: " << *Ptr << "\n");
// Walk the def-use chains.
SmallVector<const Value *, 4> Worklist;
Worklist.push_back(Ptr);
// If Ptr has any operands add them as well.
for (User::const_op_iterator I = Ptr->op_begin(), E = Ptr->op_end(); I != E;
++I) {
Worklist.push_back(*I);
}
// Ensure we do not visit any value twice.
SmallPtrSet<const Value *, 8> VisitedSet;
do {
const Value *V = Worklist.pop_back_val();
DEBUG(dbgs() << "Visiting: " << *V << "\n");
for (Value::const_use_iterator UI = V->use_begin(), UE = V->use_end();
UI != UE; ++UI) {
const User *UUser = *UI;
DEBUG(dbgs() << "User: " << *UUser << "\n");
// Special - Use by a call (callee or argument) is not considered
// to be an escape.
switch (GetBasicInstructionClass(UUser)) {
case IC_StoreWeak:
case IC_InitWeak:
case IC_StoreStrong:
case IC_Autorelease:
case IC_AutoreleaseRV: {
DEBUG(dbgs() << "User copies pointer arguments. Pointer Escapes!\n");
// These special functions make copies of their pointer arguments.
return true;
}
case IC_IntrinsicUser:
// Use by the use intrinsic is not an escape.
continue;
case IC_User:
case IC_None:
// Use by an instruction which copies the value is an escape if the
// result is an escape.
if (isa<BitCastInst>(UUser) || isa<GetElementPtrInst>(UUser) ||
isa<PHINode>(UUser) || isa<SelectInst>(UUser)) {
if (VisitedSet.insert(UUser)) {
DEBUG(dbgs() << "User copies value. Ptr escapes if result escapes."
" Adding to list.\n");
Worklist.push_back(UUser);
} else {
DEBUG(dbgs() << "Already visited node.\n");
}
continue;
}
// Use by a load is not an escape.
if (isa<LoadInst>(UUser))
continue;
// Use by a store is not an escape if the use is the address.
if (const StoreInst *SI = dyn_cast<StoreInst>(UUser))
if (V != SI->getValueOperand())
continue;
break;
default:
// Regular calls and other stuff are not considered escapes.
continue;
}
// Otherwise, conservatively assume an escape.
DEBUG(dbgs() << "Assuming ptr escapes.\n");
return true;
}
} while (!Worklist.empty());
// No escapes found.
DEBUG(dbgs() << "Ptr does not escape.\n");
return false;
}
/// This is a wrapper around getUnderlyingObjCPtr along the lines of
/// GetUnderlyingObjects except that it returns early when it sees the first
/// alloca.
@ -1188,13 +1103,9 @@ namespace {
unsigned ARCAnnotationProvenanceSourceMDKind;
#endif // ARC_ANNOATIONS
bool IsRetainBlockOptimizable(const Instruction *Inst);
bool OptimizeRetainRVCall(Function &F, Instruction *RetainRV);
void OptimizeAutoreleaseRVCall(Function &F, Instruction *AutoreleaseRV,
InstructionClass &Class);
bool OptimizeRetainBlockCall(Function &F, Instruction *RetainBlock,
InstructionClass &Class);
void OptimizeIndividualCalls(Function &F);
void CheckForCFGHazards(const BasicBlock *BB,
@ -1283,22 +1194,6 @@ void ObjCARCOpt::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
}
bool ObjCARCOpt::IsRetainBlockOptimizable(const Instruction *Inst) {
// Without the magic metadata tag, we have to assume this might be an
// objc_retainBlock call inserted to convert a block pointer to an id,
// in which case it really is needed.
if (!Inst->getMetadata(CopyOnEscapeMDKind))
return false;
// If the pointer "escapes" (not including being used in a call),
// the copy may be needed.
if (DoesRetainableObjPtrEscape(Inst))
return false;
// Otherwise, it's not needed.
return true;
}
/// Turn objc_retainAutoreleasedReturnValue into objc_retain if the operand is
/// not a return value. Or, if it can be paired with an
/// objc_autoreleaseReturnValue, delete the pair and return true.
@ -1399,41 +1294,6 @@ ObjCARCOpt::OptimizeAutoreleaseRVCall(Function &F, Instruction *AutoreleaseRV,
}
// \brief Attempt to strength reduce objc_retainBlock calls to objc_retain
// calls.
//
// Specifically: If an objc_retainBlock call has the copy_on_escape metadata and
// does not escape (following the rules of block escaping), strength reduce the
// objc_retainBlock to an objc_retain.
//
// TODO: If an objc_retainBlock call is dominated period by a previous
// objc_retainBlock call, strength reduce the objc_retainBlock to an
// objc_retain.
bool
ObjCARCOpt::OptimizeRetainBlockCall(Function &F, Instruction *Inst,
InstructionClass &Class) {
assert(GetBasicInstructionClass(Inst) == Class);
assert(IC_RetainBlock == Class);
// If we can not optimize Inst, return false.
if (!IsRetainBlockOptimizable(Inst))
return false;
Changed = true;
++NumPeeps;
DEBUG(dbgs() << "Strength reduced retainBlock => retain.\n");
DEBUG(dbgs() << "Old: " << *Inst << "\n");
CallInst *RetainBlock = cast<CallInst>(Inst);
Constant *NewDecl = EP.get(ARCRuntimeEntryPoints::EPT_Retain);
RetainBlock->setCalledFunction(NewDecl);
// Remove copy_on_escape metadata.
RetainBlock->setMetadata(CopyOnEscapeMDKind, 0);
Class = IC_Retain;
DEBUG(dbgs() << "New: " << *Inst << "\n");
return true;
}
/// Visit each call, one at a time, and make simplifications without doing any
/// additional analysis.
void ObjCARCOpt::OptimizeIndividualCalls(Function &F) {