[llvm] r189870 - [objc-arc] Remove dead code from previous commit.
Michael Gottesman
mgottesman at apple.com
Tue Sep 3 15:40:57 PDT 2013
Author: mgottesman
Date: Tue Sep 3 17:40:56 2013
New Revision: 189870
URL: http://llvm.org/viewvc/llvm-project?rev=189870&view=rev
Log:
[objc-arc] Remove dead code from previous commit.
Modified:
llvm/trunk/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
Modified: llvm/trunk/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/ObjCARC/ObjCARCOpts.cpp?rev=189870&r1=189869&r2=189870&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/ObjCARC/ObjCARCOpts.cpp (original)
+++ llvm/trunk/lib/Transforms/ObjCARC/ObjCARCOpts.cpp Tue Sep 3 17:40:56 2013
@@ -176,91 +176,6 @@ static const Value *FindSingleUseIdentif
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(Analys
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(Fu
}
-// \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) {
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