#include "llvm/IntrinsicInst.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Support/IRBuilder.h"
+#include "llvm/MC/MCAsmInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/PromoteMemToReg.h"
using namespace llvm;
-STATISTIC(NumExceptionValuesMoved, "Number of eh.exception calls moved");
-STATISTIC(NumLonelyLandingPads, "Number of landing pads with no selector");
-STATISTIC(NumLonelySelectors, "Number of lonely selectors lowered");
STATISTIC(NumLandingPadsSplit, "Number of landing pads split");
-STATISTIC(NumSelectorsAdjusted, "Number of selector results adjusted");
-STATISTIC(NumSelectorsSimplified, "Number of selectors truncated");
-STATISTIC(NumStackTempsIntroduced, "Number of stack temporaries introduced");
STATISTIC(NumUnwindsLowered, "Number of unwind instructions lowered");
+STATISTIC(NumExceptionValuesMoved, "Number of eh.exception calls moved");
+STATISTIC(NumStackTempsIntroduced, "Number of stack temporaries introduced");
namespace {
class DwarfEHPrepare : public FunctionPass {
const TargetLowering *TLI;
+ bool CompileFast;
// The eh.exception intrinsic.
- Function *ExceptionIntrinsic;
-
- // The eh.selector intrinsic.
- Function *SelectorIntrinsic;
-
- // The eh.typeid.for intrinsic.
- Function *TypeIdIntrinsic;
+ Function *ExceptionValueIntrinsic;
// _Unwind_Resume or the target equivalent.
Constant *RewindFunction;
- // _Unwind_RaiseException.
- Constant *UnwindFunction;
-
// Dominator info is used when turning stack temporaries into registers.
DominatorTree *DT;
DominanceFrontier *DF;
// The function we are running on.
Function *F;
- // The current context.
- LLVMContext *Context;
-
- // The personality and catch-all value for this function.
- Constant *Personality;
- Constant *CatchAll;
-
// The landing pads for this function.
typedef SmallPtrSet<BasicBlock*, 8> BBSet;
BBSet LandingPads;
bool NormalizeLandingPads();
bool LowerUnwinds();
- bool MoveSelectorCalls();
- bool RectifySelectorCalls();
bool MoveExceptionValueCalls();
- bool AddMissingSelectors();
bool FinishStackTemporaries();
bool PromoteStackTemporaries();
public:
static char ID; // Pass identification, replacement for typeid.
- DwarfEHPrepare(const TargetLowering *tli) :
- FunctionPass(&ID), TLI(tli), ExceptionIntrinsic(0),
- SelectorIntrinsic(0), TypeIdIntrinsic(0), RewindFunction(0),
- UnwindFunction(0) {}
+ DwarfEHPrepare(const TargetLowering *tli, bool fast) :
+ FunctionPass(&ID), TLI(tli), CompileFast(fast),
+ ExceptionValueIntrinsic(0), RewindFunction(0) {}
virtual bool runOnFunction(Function &Fn);
+ // getAnalysisUsage - We need dominance frontiers for memory promotion.
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ if (!CompileFast)
+ AU.addRequired<DominatorTree>();
+ AU.addPreserved<DominatorTree>();
+ if (!CompileFast)
+ AU.addRequired<DominanceFrontier>();
+ AU.addPreserved<DominanceFrontier>();
+ }
+
const char *getPassName() const {
return "Exception handling preparation";
}
char DwarfEHPrepare::ID = 0;
-FunctionPass *llvm::createDwarfEHPass(const TargetLowering *tli) {
- return new DwarfEHPrepare(tli);
+FunctionPass *llvm::createDwarfEHPass(const TargetLowering *tli, bool fast) {
+ return new DwarfEHPrepare(tli, fast);
}
/// NormalizeLandingPads - Normalize and discover landing pads, noting them
bool DwarfEHPrepare::NormalizeLandingPads() {
bool Changed = false;
+ const MCAsmInfo *MAI = TLI->getTargetMachine().getMCAsmInfo();
+ bool usingSjLjEH = MAI->getExceptionHandlingType() == ExceptionHandling::SjLj;
+
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
TerminatorInst *TI = I->getTerminator();
if (!isa<InvokeInst>(TI))
// Check that only invoke unwind edges end at the landing pad.
bool OnlyUnwoundTo = true;
+ bool SwitchOK = usingSjLjEH;
for (pred_iterator PI = pred_begin(LPad), PE = pred_end(LPad);
PI != PE; ++PI) {
TerminatorInst *PT = (*PI)->getTerminator();
+ // The SjLj dispatch block uses a switch instruction. This is effectively
+ // an unwind edge, so we can disregard it here. There will only ever
+ // be one dispatch, however, so if there are multiple switches, one
+ // of them truly is a normal edge, not an unwind edge.
+ if (SwitchOK && isa<SwitchInst>(PT)) {
+ SwitchOK = false;
+ continue;
+ }
if (!isa<InvokeInst>(PT) || LPad == PT->getSuccessor(0)) {
OnlyUnwoundTo = false;
break;
// edges to a new basic block which falls through into this one.
// Create the new basic block.
- BasicBlock *NewBB = BasicBlock::Create(*Context,
+ BasicBlock *NewBB = BasicBlock::Create(F->getContext(),
LPad->getName() + "_unwind_edge");
// Insert it into the function right before the original landing pad.
// Find the rewind function if we didn't already.
if (!RewindFunction) {
+ LLVMContext &Ctx = UnwindInsts[0]->getContext();
std::vector<const Type*>
- Params(1, Type::getInt8PtrTy(*Context));
- FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Context),
+ Params(1, Type::getInt8PtrTy(Ctx));
+ FunctionType *FTy = FunctionType::get(Type::getVoidTy(Ctx),
Params, false);
const char *RewindName = TLI->getLibcallName(RTLIB::UNWIND_RESUME);
RewindFunction = F->getParent()->getOrInsertFunction(RewindName, FTy);
}
+ bool Changed = false;
+
for (SmallVectorImpl<TerminatorInst*>::iterator
I = UnwindInsts.begin(), E = UnwindInsts.end(); I != E; ++I) {
TerminatorInst *TI = *I;
"", TI);
CI->setCallingConv(TLI->getLibcallCallingConv(RTLIB::UNWIND_RESUME));
// ...followed by an UnreachableInst.
- new UnreachableInst(*Context, TI);
+ new UnreachableInst(TI->getContext(), TI);
// Nuke the unwind instruction.
TI->eraseFromParent();
++NumUnwindsLowered;
- }
-
- return true;
-}
-
-/// MoveSelectorCalls - Make sure that every call to eh.selector occurs in its
-/// own landing pad, the landing pad corresponding to the exception object.
-bool DwarfEHPrepare::MoveSelectorCalls() {
- // If the eh.selector intrinsic is not declared in the module then there is
- // nothing to do. Speed up compilation by checking for this common case.
- if (!F->getParent()->getFunction(Intrinsic::getName(Intrinsic::eh_selector)))
- return false;
-
- // TODO: There is a lot of room for optimization here.
-
- bool Changed = false;
- BasicBlock *UnrBB = 0;
-
- for (Function::iterator BB = F->begin(); BB != F->end(); ++BB) {
- // If this basic block is not a landing pad then synthesize a landing pad
- // for every selector in it.
- bool SynthesizeLandingPad = !LandingPads.count(BB);
-
- for (BasicBlock::iterator II = BB->begin(), IE = BB->end(); II != IE; ++II) {
- EHSelectorInst *SI = dyn_cast<EHSelectorInst>(II);
- // Only interested in eh.selector calls.
- if (!SI)
- continue;
-
- // Note the personality and catch-all for later use.
- Personality = cast<Constant>(SI->getOperand(2));
- CatchAll = cast<Constant>(SI->getOperand(SI->getNumOperands() - 1)
- ->stripPointerCasts());
-
- // The exception object.
- Value *Exception = SI->getOperand(1);
-
- if (!SynthesizeLandingPad) {
- // Did the exception come from unwinding to this landing pad or another?
- // If it comes from a different landing pad then we need to synthesize a
- // new landing pad for the selector.
- EHExceptionInst *EI = dyn_cast<EHExceptionInst>(Exception);
- SynthesizeLandingPad = !EI || EI->getParent() != BB;
- }
-
- if (!SynthesizeLandingPad) {
- // This is the first selector in this landing pad, and it is the landing
- // pad corresponding to the exception object. No need to do anything to
- // this selector, but any subsequent selectors in this landing pad will
- // need their own invoke in order to make them independent of this one.
- SynthesizeLandingPad = true;
- continue;
- }
-
- // Rethrow the exception and catch it again, generating a landing pad for
- // this selector to live in.
-
- // Find _Unwind_RaiseException if we didn't already.
- if (!UnwindFunction) {
- std::vector<const Type*> ArgTys(1, Type::getInt8PtrTy(*Context));
- const FunctionType *FTy =
- FunctionType::get(Type::getInt32Ty(*Context), ArgTys, true);
-
- const char *Name = "_Unwind_RaiseException";
- UnwindFunction = F->getParent()->getOrInsertFunction(Name, FTy);
- }
-
- // Create a basic block containing only an unreachable instruction if we
- // didn't already.
- if (!UnrBB) {
- UnrBB = BasicBlock::Create(*Context, "unreachable", F);
- new UnreachableInst(*Context, UnrBB);
- }
-
- // Split the basic block before the selector.
- BasicBlock *NewBB = SplitBlock(BB, SI, this);
-
- // Replace the terminator with an invoke of _Unwind_RaiseException.
- BB->getTerminator()->eraseFromParent();
- InvokeInst::Create(UnwindFunction, UnrBB, NewBB, &Exception,
- 1 + &Exception, "", BB);
-
- // The split off basic block is now a landing pad.
- LandingPads.insert(NewBB);
-
- // Replace the exception argument in the selector call with a call to
- // eh.exception. This is not really necessary but it makes things more
- // regular.
- Exception = CreateExceptionValueCall(NewBB);
- SI->setOperand(1, Exception);
-
- ++NumLonelySelectors;
- Changed = true;
-
- // All instructions still in the original basic block have been scanned.
- // Move on to the next basic block.
- break;
- }
- }
-
- return Changed;
-}
-
-/// RectifySelectorCalls - Remove useless catch-all clauses from the ends of
-/// selectors, or correct the selector result for the presence of the catch-all
-/// if it is really needed.
-bool DwarfEHPrepare::RectifySelectorCalls() {
- // If the eh.selector intrinsic is not declared in the module then there is
- // nothing to do. Speed up compilation by checking for this common case.
- if (!F->getParent()->getFunction(Intrinsic::getName(Intrinsic::eh_selector)))
- return false;
-
- bool Changed = false;
-
- for (BBSet::iterator I = LandingPads.begin(), E = LandingPads.end(); I != E;
- ++I)
- for (BasicBlock::iterator II = (*I)->begin(), IE = (*I)->end(); II != IE; )
- if (EHSelectorInst *SI = dyn_cast<EHSelectorInst>(II++)) {
- // Found a call to eh.selector. Check whether it has a catch-all in the
- // middle.
- unsigned LastIndex = 0;
- for (unsigned i = 3, e = SI->getNumOperands() - 1; i < e; ++i) {
- Value *V = SI->getOperand(i);
- if (V->stripPointerCasts() == CatchAll) {
- // A catch-all. The catch-all at the end was not needed.
- LastIndex = i;
- break;
- } else if (ConstantInt *FilterLength = dyn_cast<ConstantInt>(V)) {
- // A cleanup or a filter.
- unsigned Length = FilterLength->getZExtValue();
- if (Length == 0)
- // A cleanup - skip it.
- continue;
- if (Length == 1) {
- // A catch-all filter. Drop everything that follows.
- LastIndex = i;
- break;
- }
- // A filter, skip over the typeinfos.
- i += Length - 1;
- }
- }
-
- if (LastIndex) {
- // Drop the pointless catch-all from the end. In fact drop everything
- // after LastIndex as an optimization.
- SmallVector<Value*, 16> Args;
- Args.reserve(LastIndex);
- for (unsigned i = 1; i <= LastIndex; ++i)
- Args.push_back(SI->getOperand(i));
- CallInst *CI = CallInst::Create(SI->getOperand(0), Args.begin(),
- Args.end(), "", SI);
- CI->takeName(SI);
- SI->replaceAllUsesWith(CI);
- SI->eraseFromParent();
- ++NumSelectorsSimplified;
- } else if (!isa<ConstantInt>(CatchAll) && // Not a cleanup.
- !SI->use_empty()) {
- // Correct the selector value to return zero if the catch-all matches.
- Constant *Zero = ConstantInt::getNullValue(Type::getInt32Ty(*Context));
-
- // Create the new selector value, with placeholders instead of the
- // real operands and make everyone use it. The reason for this round
- // about approach is that the computation of the new value makes use
- // of the old value, so we can't just compute it then do RAUW.
- SelectInst *S = SelectInst::Create(ConstantInt::getFalse(*Context),
- Zero, Zero, "", II);
- SI->replaceAllUsesWith(S);
-
- // Now calculate the operands of the select.
- IRBuilder<> Builder(*I, S);
-
- // Find the eh.typeid.for intrinsic if we didn't already.
- if (!TypeIdIntrinsic)
- TypeIdIntrinsic = Intrinsic::getDeclaration(F->getParent(),
- Intrinsic::eh_typeid_for);
-
- // Obtain the id of the catch-all.
- Value *CatchAllId = Builder.CreateCall(TypeIdIntrinsic,
- ConstantExpr::getBitCast(CatchAll, Type::getInt8PtrTy(*Context)));
-
- // Compare it with the original selector result. If it matched then
- // the selector result is zero, otherwise it is the original selector.
- Value *MatchesCatchAll = Builder.CreateICmpEQ(SI, CatchAllId);
- S->setOperand(0, MatchesCatchAll);
- S->setOperand(2, SI);
- ++NumSelectorsAdjusted;
- }
-
- Changed = true;
- break;
- }
-
- return Changed;
-}
-
-/// Make sure every landing pad has a selector in it.
-bool DwarfEHPrepare::AddMissingSelectors() {
- if (!Personality)
- // We only know how to codegen invokes if there is a personality.
- // FIXME: This results in wrong code.
- return false;
-
- bool Changed = false;
-
- for (BBSet::iterator I = LandingPads.begin(), E = LandingPads.end(); I != E;
- ++I) {
- bool FoundSelector = false;
-
- // Check whether the landing pad already contains a call to eh.selector.
- for (BasicBlock::iterator II = (*I)->begin(), IE = (*I)->end(); II != IE;
- ++II)
- if (isa<EHSelectorInst>(II)) {
- FoundSelector = true;
- break;
- }
-
- if (FoundSelector)
- continue;
-
- // Find the eh.selector intrinsic if we didn't already.
- if (!SelectorIntrinsic)
- SelectorIntrinsic = Intrinsic::getDeclaration(F->getParent(),
- Intrinsic::eh_selector);
-
- // Get the exception object.
- Instruction *Exception = CreateExceptionValueCall(*I);
-
- Value *Args[3] = { Exception, Personality, CatchAll };
- CallInst *Selector = CallInst::Create(SelectorIntrinsic, Args, Args + 3);
- Selector->insertAfter(Exception);
-
- ++NumLonelyLandingPads;
Changed = true;
}
bool DwarfEHPrepare::MoveExceptionValueCalls() {
// If the eh.exception intrinsic is not declared in the module then there is
// nothing to do. Speed up compilation by checking for this common case.
- if (!ExceptionIntrinsic &&
+ if (!ExceptionValueIntrinsic &&
!F->getParent()->getFunction(Intrinsic::getName(Intrinsic::eh_exception)))
return false;
if (ExceptionValueVar && DT && DF && isAllocaPromotable(ExceptionValueVar)) {
// Turn the exception temporary into registers and phi nodes if possible.
std::vector<AllocaInst*> Allocas(1, ExceptionValueVar);
- PromoteMemToReg(Allocas, *DT, *DF, *Context);
+ PromoteMemToReg(Allocas, *DT, *DF);
return true;
}
return false;
return Start;
// Find the eh.exception intrinsic if we didn't already.
- if (!ExceptionIntrinsic)
- ExceptionIntrinsic = Intrinsic::getDeclaration(F->getParent(),
+ if (!ExceptionValueIntrinsic)
+ ExceptionValueIntrinsic = Intrinsic::getDeclaration(F->getParent(),
Intrinsic::eh_exception);
// Create the call.
- return CallInst::Create(ExceptionIntrinsic, "eh.value.call", Start);
+ return CallInst::Create(ExceptionValueIntrinsic, "eh.value.call", Start);
}
/// CreateValueLoad - Insert a load of the exception value stack variable
// Create the temporary if we didn't already.
if (!ExceptionValueVar) {
ExceptionValueVar = new AllocaInst(PointerType::getUnqual(
- Type::getInt8Ty(*Context)), "eh.value", F->begin()->begin());
+ Type::getInt8Ty(BB->getContext())), "eh.value", F->begin()->begin());
++NumStackTempsIntroduced;
}
DT = getAnalysisIfAvailable<DominatorTree>();
DF = getAnalysisIfAvailable<DominanceFrontier>();
ExceptionValueVar = 0;
- Personality = 0;
- CatchAll = 0;
- Context = &Fn.getContext();
F = &Fn;
// Ensure that only unwind edges end at landing pads (a landing pad is a
// Turn unwind instructions into libcalls.
Changed |= LowerUnwinds();
- // Make sure that every call to eh.selector occurs in its own landing pad.
- Changed |= MoveSelectorCalls();
-
- // Remove useless catch-all clauses from the ends of selectors, or correct the
- // selector result for the presence of the catch-all if it is really needed.
- Changed |= RectifySelectorCalls();
-
- // Make sure every landing pad has a selector in it.
- Changed |= AddMissingSelectors();
+ // TODO: Move eh.selector calls to landing pads and combine them.
// Move eh.exception calls to landing pads.
Changed |= MoveExceptionValueCalls();
Changed |= FinishStackTemporaries();
// Turn any stack temporaries into registers if possible.
-//TODO if (!CompileFast)
-//TODO Changed |= PromoteStackTemporaries();
+ if (!CompileFast)
+ Changed |= PromoteStackTemporaries();
LandingPads.clear();
projects / oota-llvm.git / blobdiff