#include "llvm/Analysis/Dominators.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/Support/CallSite.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Transforms/Utils/PromoteMemToReg.h"
+#include "llvm/Transforms/Utils/SSAUpdater.h"
using namespace llvm;
STATISTIC(NumLandingPadsSplit, "Number of landing pads split");
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 TargetMachine *TM;
const TargetLowering *TLI;
- bool CompileFast;
// The eh.exception intrinsic.
Function *ExceptionValueIntrinsic;
// The eh.selector intrinsic.
Function *SelectorIntrinsic;
- // _Unwind_Resume_or_Rethrow call.
+ // _Unwind_Resume_or_Rethrow or _Unwind_SjLj_Resume call.
Constant *URoR;
// The EH language-specific catch-all type.
// _Unwind_Resume or the target equivalent.
Constant *RewindFunction;
- // Dominator info is used when turning stack temporaries into registers.
+ // We both use and preserve dominator info.
DominatorTree *DT;
- DominanceFrontier *DF;
// The function we are running on.
Function *F;
typedef SmallPtrSet<BasicBlock*, 8> BBSet;
BBSet LandingPads;
- // Stack temporary used to hold eh.exception values.
- AllocaInst *ExceptionValueVar;
-
bool NormalizeLandingPads();
bool LowerUnwinds();
bool MoveExceptionValueCalls();
- bool FinishStackTemporaries();
- bool PromoteStackTemporaries();
Instruction *CreateExceptionValueCall(BasicBlock *BB);
- Instruction *CreateValueLoad(BasicBlock *BB);
-
- /// CreateReadOfExceptionValue - Return the result of the eh.exception
- /// intrinsic by calling the intrinsic if in a landing pad, or loading it
- /// from the exception value variable otherwise.
- Instruction *CreateReadOfExceptionValue(BasicBlock *BB) {
- return LandingPads.count(BB) ?
- CreateExceptionValueCall(BB) : CreateValueLoad(BB);
- }
/// CleanupSelectors - Any remaining eh.selector intrinsic calls which still
- /// use the ".llvm.eh.catch.all.value" call need to convert to using its
+ /// use the "llvm.eh.catch.all.value" call need to convert to using its
/// initializer instead.
- bool CleanupSelectors();
+ bool CleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels);
+
+ bool HasCatchAllInSelector(IntrinsicInst *);
/// FindAllCleanupSelectors - Find all eh.selector calls that are clean-ups.
- void FindAllCleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels);
+ void FindAllCleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels,
+ SmallPtrSet<IntrinsicInst*, 32> &CatchAllSels);
/// FindAllURoRInvokes - Find all URoR invokes in the function.
void FindAllURoRInvokes(SmallPtrSet<InvokeInst*, 32> &URoRInvokes);
- /// HandleURoRInvokes - Handle invokes of "_Unwind_Resume_or_Rethrow"
- /// calls. The "unwind" part of these invokes jump to a landing pad within
- /// the current function. This is a candidate to merge the selector
- /// associated with the URoR invoke with the one from the URoR's landing
- /// pad.
+ /// HandleURoRInvokes - Handle invokes of "_Unwind_Resume_or_Rethrow" or
+ /// "_Unwind_SjLj_Resume" calls. The "unwind" part of these invokes jump to
+ /// a landing pad within the current function. This is a candidate to merge
+ /// the selector associated with the URoR invoke with the one from the
+ /// URoR's landing pad.
bool HandleURoRInvokes();
/// FindSelectorAndURoR - Find the eh.selector call and URoR call associated
/// with the eh.exception call. This recursively looks past instructions
/// which don't change the EH pointer value, like casts or PHI nodes.
bool FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
- SmallPtrSet<IntrinsicInst*, 8> &SelCalls);
+ SmallPtrSet<IntrinsicInst*, 8> &SelCalls,
+ SmallPtrSet<PHINode*, 32> &SeenPHIs);
- /// DoMem2RegPromotion - Take an alloca call and promote it from memory to a
- /// register.
- bool DoMem2RegPromotion(Value *V) {
- AllocaInst *AI = dyn_cast<AllocaInst>(V);
- if (!AI || !isAllocaPromotable(AI)) return false;
-
- // Turn the alloca into a register.
- std::vector<AllocaInst*> Allocas(1, AI);
- PromoteMemToReg(Allocas, *DT, *DF);
- return true;
- }
-
- /// PromoteStoreInst - Perform Mem2Reg on a StoreInst.
- bool PromoteStoreInst(StoreInst *SI) {
- if (!SI || !DT || !DF) return false;
- if (DoMem2RegPromotion(SI->getOperand(1)))
- return true;
- return false;
- }
-
- /// PromoteEHPtrStore - Promote the storing of an EH pointer into a
- /// register. This should get rid of the store and subsequent loads.
- bool PromoteEHPtrStore(IntrinsicInst *II) {
- if (!DT || !DF) return false;
-
- bool Changed = false;
- StoreInst *SI;
-
- while (1) {
- SI = 0;
- for (Value::use_iterator
- I = II->use_begin(), E = II->use_end(); I != E; ++I) {
- SI = dyn_cast<StoreInst>(I);
- if (SI) break;
- }
-
- if (!PromoteStoreInst(SI))
- break;
-
- Changed = true;
- }
-
- return false;
- }
-
public:
static char ID; // Pass identification, replacement for typeid.
- DwarfEHPrepare(const TargetLowering *tli, bool fast) :
- FunctionPass(&ID), TLI(tli), CompileFast(fast),
+ DwarfEHPrepare(const TargetMachine *tm) :
+ FunctionPass(ID), TM(tm), TLI(TM->getTargetLowering()),
ExceptionValueIntrinsic(0), SelectorIntrinsic(0),
- URoR(0), EHCatchAllValue(0), RewindFunction(0) {}
+ URoR(0), EHCatchAllValue(0), RewindFunction(0) {
+ initializeDominatorTreePass(*PassRegistry::getPassRegistry());
+ }
virtual bool runOnFunction(Function &Fn);
- // getAnalysisUsage - We need dominance frontiers for memory promotion.
+ // getAnalysisUsage - We need the dominator tree for handling URoR.
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- if (!CompileFast)
- AU.addRequired<DominatorTree>();
+ AU.addRequired<DominatorTree>();
AU.addPreserved<DominatorTree>();
- if (!CompileFast)
- AU.addRequired<DominanceFrontier>();
- AU.addPreserved<DominanceFrontier>();
}
const char *getPassName() const {
char DwarfEHPrepare::ID = 0;
-FunctionPass *llvm::createDwarfEHPass(const TargetLowering *tli, bool fast) {
- return new DwarfEHPrepare(tli, fast);
+FunctionPass *llvm::createDwarfEHPass(const TargetMachine *tm) {
+ return new DwarfEHPrepare(tm);
+}
+
+/// HasCatchAllInSelector - Return true if the intrinsic instruction has a
+/// catch-all.
+bool DwarfEHPrepare::HasCatchAllInSelector(IntrinsicInst *II) {
+ if (!EHCatchAllValue) return false;
+
+ unsigned ArgIdx = II->getNumArgOperands() - 1;
+ GlobalVariable *GV = dyn_cast<GlobalVariable>(II->getArgOperand(ArgIdx));
+ return GV == EHCatchAllValue;
}
/// FindAllCleanupSelectors - Find all eh.selector calls that are clean-ups.
void DwarfEHPrepare::
-FindAllCleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels) {
+FindAllCleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels,
+ SmallPtrSet<IntrinsicInst*, 32> &CatchAllSels) {
for (Value::use_iterator
I = SelectorIntrinsic->use_begin(),
E = SelectorIntrinsic->use_end(); I != E; ++I) {
- IntrinsicInst *SI = cast<IntrinsicInst>(I);
- if (!SI || SI->getParent()->getParent() != F) continue;
+ IntrinsicInst *II = cast<IntrinsicInst>(*I);
- unsigned NumOps = SI->getNumOperands();
- if (NumOps > 4) continue;
- bool IsCleanUp = (NumOps == 3);
-
- if (!IsCleanUp)
- if (ConstantInt *CI = dyn_cast<ConstantInt>(SI->getOperand(2)))
- IsCleanUp = (CI->getZExtValue() == 0);
+ if (II->getParent()->getParent() != F)
+ continue;
- if (IsCleanUp)
- Sels.insert(SI);
+ if (!HasCatchAllInSelector(II))
+ Sels.insert(II);
+ else
+ CatchAllSels.insert(II);
}
}
for (Value::use_iterator
I = URoR->use_begin(),
E = URoR->use_end(); I != E; ++I) {
- if (InvokeInst *II = dyn_cast<InvokeInst>(I))
+ if (InvokeInst *II = dyn_cast<InvokeInst>(*I))
URoRInvokes.insert(II);
}
}
/// CleanupSelectors - Any remaining eh.selector intrinsic calls which still use
-/// the ".llvm.eh.catch.all.value" call need to convert to using its
+/// the "llvm.eh.catch.all.value" call need to convert to using its
/// initializer instead.
-bool DwarfEHPrepare::CleanupSelectors() {
+bool DwarfEHPrepare::CleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels) {
if (!EHCatchAllValue) return false;
if (!SelectorIntrinsic) {
}
bool Changed = false;
- for (Value::use_iterator
- I = SelectorIntrinsic->use_begin(),
- E = SelectorIntrinsic->use_end(); I != E; ++I) {
- IntrinsicInst *Sel = dyn_cast<IntrinsicInst>(I);
- if (!Sel || Sel->getParent()->getParent() != F) continue;
+ for (SmallPtrSet<IntrinsicInst*, 32>::iterator
+ I = Sels.begin(), E = Sels.end(); I != E; ++I) {
+ IntrinsicInst *Sel = *I;
- // Index of the ".llvm.eh.catch.all.value" variable.
- unsigned OpIdx = Sel->getNumOperands() - 2;
- GlobalVariable *GV = dyn_cast<GlobalVariable>(Sel->getOperand(OpIdx));
+ // Index of the "llvm.eh.catch.all.value" variable.
+ unsigned OpIdx = Sel->getNumArgOperands() - 1;
+ GlobalVariable *GV = dyn_cast<GlobalVariable>(Sel->getArgOperand(OpIdx));
if (GV != EHCatchAllValue) continue;
- Sel->setOperand(OpIdx, EHCatchAllValue->getInitializer());
+ Sel->setArgOperand(OpIdx, EHCatchAllValue->getInitializer());
Changed = true;
}
/// change the EH pointer value, like casts or PHI nodes.
bool
DwarfEHPrepare::FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
- SmallPtrSet<IntrinsicInst*, 8> &SelCalls) {
- SmallPtrSet<PHINode*, 32> SeenPHIs;
+ SmallPtrSet<IntrinsicInst*, 8> &SelCalls,
+ SmallPtrSet<PHINode*, 32> &SeenPHIs) {
bool Changed = false;
- restart:
for (Value::use_iterator
I = Inst->use_begin(), E = Inst->use_end(); I != E; ++I) {
- Instruction *II = dyn_cast<Instruction>(I);
+ Instruction *II = dyn_cast<Instruction>(*I);
if (!II || II->getParent()->getParent() != F) continue;
if (IntrinsicInst *Sel = dyn_cast<IntrinsicInst>(II)) {
if (Invoke->getCalledFunction() == URoR)
URoRInvoke = true;
} else if (CastInst *CI = dyn_cast<CastInst>(II)) {
- Changed |= FindSelectorAndURoR(CI, URoRInvoke, SelCalls);
- } else if (StoreInst *SI = dyn_cast<StoreInst>(II)) {
- if (!PromoteStoreInst(SI)) continue;
- Changed = true;
- SeenPHIs.clear();
- goto restart; // Uses may have changed, restart loop.
+ Changed |= FindSelectorAndURoR(CI, URoRInvoke, SelCalls, SeenPHIs);
} else if (PHINode *PN = dyn_cast<PHINode>(II)) {
if (SeenPHIs.insert(PN))
// Don't process a PHI node more than once.
- Changed |= FindSelectorAndURoR(PN, URoRInvoke, SelCalls);
+ Changed |= FindSelectorAndURoR(PN, URoRInvoke, SelCalls, SeenPHIs);
}
}
return Changed;
}
-/// HandleURoRInvokes - Handle invokes of "_Unwind_Resume_or_Rethrow" calls. The
-/// "unwind" part of these invokes jump to a landing pad within the current
-/// function. This is a candidate to merge the selector associated with the URoR
-/// invoke with the one from the URoR's landing pad.
+/// HandleURoRInvokes - Handle invokes of "_Unwind_Resume_or_Rethrow" or
+/// "_Unwind_SjLj_Resume" calls. The "unwind" part of these invokes jump to a
+/// landing pad within the current function. This is a candidate to merge the
+/// selector associated with the URoR invoke with the one from the URoR's
+/// landing pad.
bool DwarfEHPrepare::HandleURoRInvokes() {
- if (!DT) return CleanupSelectors(); // We require DominatorTree information.
-
if (!EHCatchAllValue) {
EHCatchAllValue =
- F->getParent()->getNamedGlobal(".llvm.eh.catch.all.value");
+ F->getParent()->getNamedGlobal("llvm.eh.catch.all.value");
if (!EHCatchAllValue) return false;
}
if (!SelectorIntrinsic) return false;
}
+ SmallPtrSet<IntrinsicInst*, 32> Sels;
+ SmallPtrSet<IntrinsicInst*, 32> CatchAllSels;
+ FindAllCleanupSelectors(Sels, CatchAllSels);
+
if (!URoR) {
URoR = F->getParent()->getFunction("_Unwind_Resume_or_Rethrow");
- if (!URoR) return CleanupSelectors();
+ if (!URoR) {
+ URoR = F->getParent()->getFunction("_Unwind_SjLj_Resume");
+ if (!URoR) return CleanupSelectors(CatchAllSels);
+ }
}
- SmallPtrSet<IntrinsicInst*, 32> Sels;
SmallPtrSet<InvokeInst*, 32> URoRInvokes;
- FindAllCleanupSelectors(Sels);
FindAllURoRInvokes(URoRInvokes);
SmallPtrSet<IntrinsicInst*, 32> SelsToConvert;
for (SmallPtrSet<InvokeInst*, 32>::iterator
UI = URoRInvokes.begin(), UE = URoRInvokes.end(); UI != UE; ++UI) {
const BasicBlock *URoRBB = (*UI)->getParent();
- if (SelBB == URoRBB || DT->dominates(SelBB, URoRBB)) {
+ if (DT->dominates(SelBB, URoRBB)) {
SelsToConvert.insert(*SI);
break;
}
if (!ExceptionValueIntrinsic) {
ExceptionValueIntrinsic =
Intrinsic::getDeclaration(F->getParent(), Intrinsic::eh_exception);
- if (!ExceptionValueIntrinsic) return CleanupSelectors();
+ if (!ExceptionValueIntrinsic)
+ return CleanupSelectors(CatchAllSels);
}
for (Value::use_iterator
I = ExceptionValueIntrinsic->use_begin(),
E = ExceptionValueIntrinsic->use_end(); I != E; ++I) {
- IntrinsicInst *EHPtr = dyn_cast<IntrinsicInst>(I);
+ IntrinsicInst *EHPtr = dyn_cast<IntrinsicInst>(*I);
if (!EHPtr || EHPtr->getParent()->getParent() != F) continue;
- Changed |= PromoteEHPtrStore(EHPtr);
-
bool URoRInvoke = false;
SmallPtrSet<IntrinsicInst*, 8> SelCalls;
- Changed |= FindSelectorAndURoR(EHPtr, URoRInvoke, SelCalls);
+ SmallPtrSet<PHINode*, 32> SeenPHIs;
+ Changed |= FindSelectorAndURoR(EHPtr, URoRInvoke, SelCalls, SeenPHIs);
if (URoRInvoke) {
// This EH pointer is being used by an invoke of an URoR instruction and
// an eh.selector intrinsic call. If the eh.selector is a 'clean-up', we
// need to convert it to a 'catch-all'.
for (SmallPtrSet<IntrinsicInst*, 8>::iterator
- SI = SelCalls.begin(), SE = SelCalls.end(); SI != SE; ++SI) {
- IntrinsicInst *II = *SI;
- unsigned NumOps = II->getNumOperands();
-
- if (NumOps <= 4) {
- bool IsCleanUp = (NumOps == 3);
-
- if (!IsCleanUp)
- if (ConstantInt *CI = dyn_cast<ConstantInt>(II->getOperand(2)))
- IsCleanUp = (CI->getZExtValue() == 0);
-
- if (IsCleanUp)
- SelsToConvert.insert(II);
- }
- }
+ SI = SelCalls.begin(), SE = SelCalls.end(); SI != SE; ++SI)
+ if (!HasCatchAllInSelector(*SI))
+ SelsToConvert.insert(*SI);
}
}
}
SI = SelsToConvert.begin(), SE = SelsToConvert.end();
SI != SE; ++SI) {
IntrinsicInst *II = *SI;
- SmallVector<Value*, 8> Args;
// Use the exception object pointer and the personality function
// from the original selector.
- Args.push_back(II->getOperand(0)); // Exception object pointer.
- Args.push_back(II->getOperand(1)); // Personality function.
+ CallSite CS(II);
+ IntrinsicInst::op_iterator I = CS.arg_begin();
+ IntrinsicInst::op_iterator E = CS.arg_end();
+ IntrinsicInst::op_iterator B = prior(E);
+
+ // Exclude last argument if it is an integer.
+ if (isa<ConstantInt>(B)) E = B;
+
+ // Add exception object pointer (front).
+ // Add personality function (next).
+ // Add in any filter IDs (rest).
+ SmallVector<Value*, 8> Args(I, E);
+
Args.push_back(EHCatchAllValue->getInitializer()); // Catch-all indicator.
CallInst *NewSelector =
}
}
- Changed |= CleanupSelectors();
+ Changed |= CleanupSelectors(CatchAllSels);
return Changed;
}
bool DwarfEHPrepare::NormalizeLandingPads() {
bool Changed = false;
- const MCAsmInfo *MAI = TLI->getTargetMachine().getMCAsmInfo();
+ const MCAsmInfo *MAI = TM->getMCAsmInfo();
bool usingSjLjEH = MAI->getExceptionHandlingType() == ExceptionHandling::SjLj;
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
if (InVal == 0) {
// Different unwind edges have different values. Create a new PHI node
// in NewBB.
- PHINode *NewPN = PHINode::Create(PN->getType(), PN->getName()+".unwind",
- NewBB);
+ PHINode *NewPN = PHINode::Create(PN->getType(),
+ PN->getNumIncomingValues(),
+ PN->getName()+".unwind", NewBB);
// Add an entry for each unwind edge, using the value from the old PHI.
for (pred_iterator PI = PB; PI != PE; ++PI)
NewPN->addIncoming(PN->getIncomingValueForBlock(*PI), *PI);
// Add a fallthrough from NewBB to the original landing pad.
BranchInst::Create(LPad, NewBB);
- // Now update DominatorTree and DominanceFrontier analysis information.
- if (DT)
- DT->splitBlock(NewBB);
- if (DF)
- DF->splitBlock(NewBB);
+ // Now update DominatorTree analysis information.
+ DT->splitBlock(NewBB);
// Remember the newly constructed landing pad. The original landing pad
// LPad is no longer a landing pad now that all unwind edges have been
// Create the call...
CallInst *CI = CallInst::Create(RewindFunction,
- CreateReadOfExceptionValue(TI->getParent()),
+ CreateExceptionValueCall(TI->getParent()),
"", TI);
CI->setCallingConv(TLI->getLibcallCallingConv(RTLIB::UNWIND_RESUME));
// ...followed by an UnreachableInst.
}
/// MoveExceptionValueCalls - Ensure that eh.exception is only ever called from
-/// landing pads by replacing calls outside of landing pads with loads from a
-/// stack temporary. Move eh.exception calls inside landing pads to the start
-/// of the landing pad (optional, but may make things simpler for later passes).
+/// landing pads by replacing calls outside of landing pads with direct use of
+/// a register holding the appropriate value; this requires adding calls inside
+/// all landing pads to initialize the register. Also, move eh.exception calls
+/// inside landing pads to the start of the landing pad (optional, but may make
+/// things simpler for later passes).
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.
bool Changed = false;
- for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
- for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E;)
- if (IntrinsicInst *CI = dyn_cast<IntrinsicInst>(II++))
- if (CI->getIntrinsicID() == Intrinsic::eh_exception) {
- if (!CI->use_empty()) {
- Value *ExceptionValue = CreateReadOfExceptionValue(BB);
- if (CI == ExceptionValue) {
- // The call was at the start of a landing pad - leave it alone.
- assert(LandingPads.count(BB) &&
- "Created eh.exception call outside landing pad!");
- continue;
- }
- CI->replaceAllUsesWith(ExceptionValue);
- }
- CI->eraseFromParent();
- ++NumExceptionValuesMoved;
- Changed = true;
+ // Move calls to eh.exception that are inside a landing pad to the start of
+ // the landing pad.
+ for (BBSet::const_iterator LI = LandingPads.begin(), LE = LandingPads.end();
+ LI != LE; ++LI) {
+ BasicBlock *LP = *LI;
+ for (BasicBlock::iterator II = LP->getFirstNonPHIOrDbg(), IE = LP->end();
+ II != IE;)
+ if (EHExceptionInst *EI = dyn_cast<EHExceptionInst>(II++)) {
+ // Found a call to eh.exception.
+ if (!EI->use_empty()) {
+ // If there is already a call to eh.exception at the start of the
+ // landing pad, then get hold of it; otherwise create such a call.
+ Value *CallAtStart = CreateExceptionValueCall(LP);
+
+ // If the call was at the start of a landing pad then leave it alone.
+ if (EI == CallAtStart)
+ continue;
+ EI->replaceAllUsesWith(CallAtStart);
}
+ EI->eraseFromParent();
+ ++NumExceptionValuesMoved;
+ Changed = true;
+ }
}
- return Changed;
-}
-
-/// FinishStackTemporaries - If we introduced a stack variable to hold the
-/// exception value then initialize it in each landing pad.
-bool DwarfEHPrepare::FinishStackTemporaries() {
- if (!ExceptionValueVar)
- // Nothing to do.
- return false;
+ // Look for calls to eh.exception that are not in a landing pad. If one is
+ // found, then a register that holds the exception value will be created in
+ // each landing pad, and the SSAUpdater will be used to compute the values
+ // returned by eh.exception calls outside of landing pads.
+ SSAUpdater SSA;
+
+ // Remember where we found the eh.exception call, to avoid rescanning earlier
+ // basic blocks which we already know contain no eh.exception calls.
+ bool FoundCallOutsideLandingPad = false;
+ Function::iterator BB = F->begin();
+ for (Function::iterator BE = F->end(); BB != BE; ++BB) {
+ // Skip over landing pads.
+ if (LandingPads.count(BB))
+ continue;
- bool Changed = false;
+ for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
+ II != IE; ++II)
+ if (isa<EHExceptionInst>(II)) {
+ SSA.Initialize(II->getType(), II->getName());
+ FoundCallOutsideLandingPad = true;
+ break;
+ }
- // Make sure that there is a store of the exception value at the start of
- // each landing pad.
- for (BBSet::iterator LI = LandingPads.begin(), LE = LandingPads.end();
- LI != LE; ++LI) {
- Instruction *ExceptionValue = CreateReadOfExceptionValue(*LI);
- Instruction *Store = new StoreInst(ExceptionValue, ExceptionValueVar);
- Store->insertAfter(ExceptionValue);
- Changed = true;
+ if (FoundCallOutsideLandingPad)
+ break;
}
- return Changed;
-}
+ // If all calls to eh.exception are in landing pads then we are done.
+ if (!FoundCallOutsideLandingPad)
+ return Changed;
-/// PromoteStackTemporaries - Turn any stack temporaries we introduced into
-/// registers if possible.
-bool DwarfEHPrepare::PromoteStackTemporaries() {
- 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);
- return true;
+ // Add a call to eh.exception at the start of each landing pad, and tell the
+ // SSAUpdater that this is the value produced by the landing pad.
+ for (BBSet::iterator LI = LandingPads.begin(), LE = LandingPads.end();
+ LI != LE; ++LI)
+ SSA.AddAvailableValue(*LI, CreateExceptionValueCall(*LI));
+
+ // Now turn all calls to eh.exception that are not in a landing pad into a use
+ // of the appropriate register.
+ for (Function::iterator BE = F->end(); BB != BE; ++BB) {
+ // Skip over landing pads.
+ if (LandingPads.count(BB))
+ continue;
+
+ for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
+ II != IE;)
+ if (EHExceptionInst *EI = dyn_cast<EHExceptionInst>(II++)) {
+ // Found a call to eh.exception, replace it with the value from any
+ // upstream landing pad(s).
+ EI->replaceAllUsesWith(SSA.GetValueAtEndOfBlock(BB));
+ EI->eraseFromParent();
+ ++NumExceptionValuesMoved;
+ }
}
- return false;
+
+ return true;
}
/// CreateExceptionValueCall - Insert a call to the eh.exception intrinsic at
return CallInst::Create(ExceptionValueIntrinsic, "eh.value.call", Start);
}
-/// CreateValueLoad - Insert a load of the exception value stack variable
-/// (creating it if necessary) at the start of the basic block (unless
-/// there already is a load, in which case the existing load is returned).
-Instruction *DwarfEHPrepare::CreateValueLoad(BasicBlock *BB) {
- Instruction *Start = BB->getFirstNonPHIOrDbg();
- // Is this a load of the exception temporary?
- if (ExceptionValueVar)
- if (LoadInst* LI = dyn_cast<LoadInst>(Start))
- if (LI->getPointerOperand() == ExceptionValueVar)
- // Reuse the existing load.
- return Start;
-
- // Create the temporary if we didn't already.
- if (!ExceptionValueVar) {
- ExceptionValueVar = new AllocaInst(PointerType::getUnqual(
- Type::getInt8Ty(BB->getContext())), "eh.value", F->begin()->begin());
- ++NumStackTempsIntroduced;
- }
-
- // Load the value.
- return new LoadInst(ExceptionValueVar, "eh.value.load", Start);
-}
-
bool DwarfEHPrepare::runOnFunction(Function &Fn) {
bool Changed = false;
// Initialize internal state.
- DT = getAnalysisIfAvailable<DominatorTree>();
- DF = getAnalysisIfAvailable<DominanceFrontier>();
- ExceptionValueVar = 0;
+ DT = &getAnalysis<DominatorTree>();
F = &Fn;
// Ensure that only unwind edges end at landing pads (a landing pad is a
// Move eh.exception calls to landing pads.
Changed |= MoveExceptionValueCalls();
- // Initialize any stack temporaries we introduced.
- Changed |= FinishStackTemporaries();
-
- // Turn any stack temporaries into registers if possible.
- if (!CompileFast)
- Changed |= PromoteStackTemporaries();
-
Changed |= HandleURoRInvokes();
LandingPads.clear();
projects / oota-llvm.git / blobdiff