6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-09-30 04:56:49 +00:00
Code Issues Projects Releases Wiki Activity

[objc-arc-contract] Refactor out tryToPeepholeInstruction into its own method. NFC.

Browse Source 
The main method of ObjCARCContract is really large and busy. By refactoring this
out, it becomes easier to reason about.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229794 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Michael Gottesman 2015-02-19 00:42:30 +00:00
parent 7e1c99b759
commit 855f109cc0
1 changed files with 85 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

143
lib/Transforms/ObjCARC/ObjCARCContract.cpp
View File

@ -72,6 +72,13 @@ namespace {
/// "tail".
SmallPtrSet<CallInst *, 8> StoreStrongCalls;
/// Returns true if we eliminated Inst.
bool tryToPeepholeInstruction(Function &F, Instruction *Inst,
inst_iterator &Iter,
SmallPtrSetImpl<Instruction *> &DepInsts,
SmallPtrSetImpl<const BasicBlock *> &Visited,
bool &TailOkForStoreStrong);
bool optimizeRetainCall(Function &F, Instruction *Retain);
bool
@ -169,18 +176,16 @@ bool ObjCARCContract::contractAutorelease(
Changed = true;
++NumPeeps;
DEBUG(dbgs() << "ObjCARCContract::ContractAutorelease: Fusing "
"retain/autorelease. Erasing: " << *Autorelease << "\n"
" Old Retain: "
<< *Retain << "\n");
DEBUG(dbgs() << " Fusing retain/autorelease!\n"
" Autorelease:" << *Autorelease << "\n"
" Retain: " << *Retain << "\n");
Constant *Decl = EP.get(Class == IC_AutoreleaseRV ?
ARCRuntimeEntryPoints::EPT_RetainAutoreleaseRV :
ARCRuntimeEntryPoints::EPT_RetainAutorelease);
Retain->setCalledFunction(Decl);
DEBUG(dbgs() << " New Retain: "
<< *Retain << "\n");
DEBUG(dbgs() << " New RetainAutorelease: " << *Retain << "\n");
EraseInstruction(Autorelease);
return true;
@ -249,6 +254,14 @@ void ObjCARCContract::contractRelease(Instruction *Release,
Changed = true;
++NumStoreStrongs;
DEBUG(
llvm::dbgs() << " Contracting retain, release into objc_storeStrong.\n"
<< " Old:\n"
<< " Store: " << *Store << "\n"
<< " Release: " << *Release << "\n"
<< " Retain: " << *Retain << "\n"
<< " Load: " << *Load << "\n");
LLVMContext &C = Release->getContext();
Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
Type *I8XX = PointerType::getUnqual(I8X);
@ -268,6 +281,8 @@ void ObjCARCContract::contractRelease(Instruction *Release,
// we can set the tail flag once we know it's safe.
StoreStrongCalls.insert(StoreStrong);
DEBUG(llvm::dbgs() << " New Store Strong: " << *StoreStrong << "\n");
if (&*Iter == Store) ++Iter;
Store->eraseFromParent();
Release->eraseFromParent();
@ -276,61 +291,26 @@ void ObjCARCContract::contractRelease(Instruction *Release,
Load->eraseFromParent();
}
//===----------------------------------------------------------------------===//
// Top Level Driver
//===----------------------------------------------------------------------===//
bool ObjCARCContract::runOnFunction(Function &F) {
if (!EnableARCOpts)
return false;
// If nothing in the Module uses ARC, don't do anything.
if (!Run)
return false;
Changed = false;
AA = &getAnalysis<AliasAnalysis>();
DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
PA.setAA(&getAnalysis<AliasAnalysis>());
DEBUG(llvm::dbgs() << "**** ObjCARC Contract ****\n");
// Track whether it's ok to mark objc_storeStrong calls with the "tail"
// keyword. Be conservative if the function has variadic arguments.
// It seems that functions which "return twice" are also unsafe for the
// "tail" argument, because they are setjmp, which could need to
// return to an earlier stack state.
bool TailOkForStoreStrongs = !F.isVarArg() &&
!F.callsFunctionThatReturnsTwice();
// For ObjC library calls which return their argument, replace uses of the
// argument with uses of the call return value, if it dominates the use. This
// reduces register pressure.
SmallPtrSet<Instruction *, 4> DependingInstructions;
SmallPtrSet<const BasicBlock *, 4> Visited;
for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ) {
Instruction *Inst = &*I++;
DEBUG(dbgs() << "Visiting: " << *Inst << "\n");
bool ObjCARCContract::tryToPeepholeInstruction(
Function &F, Instruction *Inst, inst_iterator &Iter,
SmallPtrSetImpl<Instruction *> &DependingInsts,
SmallPtrSetImpl<const BasicBlock *> &Visited,
bool &TailOkForStoreStrongs) {
// Only these library routines return their argument. In particular,
// objc_retainBlock does not necessarily return its argument.
InstructionClass Class = GetBasicInstructionClass(Inst);
switch (Class) {
case IC_FusedRetainAutorelease:
case IC_FusedRetainAutoreleaseRV:
break;
return false;
case IC_Autorelease:
case IC_AutoreleaseRV:
if (contractAutorelease(F, Inst, Class, DependingInstructions, Visited))
continue;
break;
return contractAutorelease(F, Inst, Class, DependingInsts, Visited);
case IC_Retain:
// Attempt to convert retains to retainrvs if they are next to function
// calls.
if (!optimizeRetainCall(F, Inst))
break;
return false;
// If we succeed in our optimization, fall through.
// FALLTHROUGH
case IC_RetainRV: {
@ -338,7 +318,7 @@ bool ObjCARCContract::runOnFunction(Function &F) {
// marker to do the retainAutoreleasedReturnValue optimization,
// insert it now.
if (!RetainRVMarker)
break;
return false;
BasicBlock::iterator BBI = Inst;
BasicBlock *InstParent = Inst->getParent();
@ -368,7 +348,7 @@ bool ObjCARCContract::runOnFunction(Function &F) {
CallInst::Create(IA, "", Inst);
}
decline_rv_optimization:
break;
return false;
}
case IC_InitWeak: {
// objc_initWeak(p, null) => *p = null
@ -385,31 +365,78 @@ bool ObjCARCContract::runOnFunction(Function &F) {
CI->replaceAllUsesWith(Null);
CI->eraseFromParent();
}
continue;
return true;
}
case IC_Release:
contractRelease(Inst, I);
continue;
contractRelease(Inst, Iter);
return true;
case IC_User:
// Be conservative if the function has any alloca instructions.
// Technically we only care about escaping alloca instructions,
// but this is sufficient to handle some interesting cases.
if (isa<AllocaInst>(Inst))
TailOkForStoreStrongs = false;
continue;
return true;
case IC_IntrinsicUser:
// Remove calls to @clang.arc.use(...).
Inst->eraseFromParent();
continue;
return true;
default:
continue;
return true;
}
}
DEBUG(dbgs() << "Finished List.\n\n");
//===----------------------------------------------------------------------===//
// Top Level Driver
//===----------------------------------------------------------------------===//
bool ObjCARCContract::runOnFunction(Function &F) {
if (!EnableARCOpts)
return false;
// If nothing in the Module uses ARC, don't do anything.
if (!Run)
return false;
Changed = false;
AA = &getAnalysis<AliasAnalysis>();
DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
PA.setAA(&getAnalysis<AliasAnalysis>());
DEBUG(llvm::dbgs() << "**** ObjCARC Contract ****\n");
// Track whether it's ok to mark objc_storeStrong calls with the "tail"
// keyword. Be conservative if the function has variadic arguments.
// It seems that functions which "return twice" are also unsafe for the
// "tail" argument, because they are setjmp, which could need to
// return to an earlier stack state.
bool TailOkForStoreStrongs =
!F.isVarArg() && !F.callsFunctionThatReturnsTwice();
// For ObjC library calls which return their argument, replace uses of the
// argument with uses of the call return value, if it dominates the use. This
// reduces register pressure.
SmallPtrSet<Instruction *, 4> DependingInstructions;
SmallPtrSet<const BasicBlock *, 4> Visited;
for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E;) {
Instruction *Inst = &*I++;
DEBUG(dbgs() << "Visiting: " << *Inst << "\n");
// First try to peephole Inst. If there is nothing further we can do in
// terms of undoing objc-arc-expand, process the next inst.
if (tryToPeepholeInstruction(F, Inst, I, DependingInstructions, Visited,
TailOkForStoreStrongs))
continue;
// Otherwise, try to undo objc-arc-expand.
// Don't use GetObjCArg because we don't want to look through bitcasts
// and such; to do the replacement, the argument must have type i8*.
Value *Arg = cast<CallInst>(Inst)->getArgOperand(0);
// TODO: Change this to a do-while.
for (;;) {
// If we're compiling bugpointed code, don't get in trouble.
if (!isa<Instruction>(Arg) && !isa<Argument>(Arg))