//===----------------------------------------------------------------------===//
//
// This pass mulches exception handling code into a form adapted to code
-// generation. Required if using dwarf exception handling.
+// generation. Required if using dwarf exception handling.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "dwarfehprepare"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Analysis/Dominators.h"
-#include "llvm/CodeGen/Passes.h"
#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
-#include "llvm/Support/Compiler.h"
+#include "llvm/ADT/Statistic.h"
+#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"
STATISTIC(NumStackTempsIntroduced, "Number of stack temporaries introduced");
namespace {
- class VISIBILITY_HIDDEN DwarfEHPrepare : public FunctionPass {
+ 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.
+ Constant *URoR;
+
+ // The EH language-specific catch-all type.
+ GlobalVariable *EHCatchAllValue;
+
// _Unwind_Resume or the target equivalent.
Constant *RewindFunction;
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.
+ /// 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
+ /// initializer instead.
+ 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,
+ 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.
+ 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);
+
+ /// 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 Changed;
+ }
+
public:
static char ID; // Pass identification, replacement for typeid.
- DwarfEHPrepare(const TargetLowering *tli, bool fast) :
- FunctionPass(&ID), TLI(tli), CompileFast(fast),
- ExceptionValueIntrinsic(0), RewindFunction(0) {}
+ DwarfEHPrepare(const TargetMachine *tm, bool fast) :
+ FunctionPass(ID), TM(tm), TLI(TM->getTargetLowering()),
+ CompileFast(fast),
+ ExceptionValueIntrinsic(0), SelectorIntrinsic(0),
+ URoR(0), EHCatchAllValue(0), RewindFunction(0) {}
virtual bool runOnFunction(Function &Fn);
char DwarfEHPrepare::ID = 0;
-FunctionPass *llvm::createDwarfEHPass(const TargetLowering *tli, bool fast) {
- return new DwarfEHPrepare(tli, fast);
+FunctionPass *llvm::createDwarfEHPass(const TargetMachine *tm, bool fast) {
+ return new DwarfEHPrepare(tm, fast);
+}
+
+/// 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,
+ SmallPtrSet<IntrinsicInst*, 32> &CatchAllSels) {
+ for (Value::use_iterator
+ I = SelectorIntrinsic->use_begin(),
+ E = SelectorIntrinsic->use_end(); I != E; ++I) {
+ IntrinsicInst *II = cast<IntrinsicInst>(*I);
+
+ if (II->getParent()->getParent() != F)
+ continue;
+
+ if (!HasCatchAllInSelector(II))
+ Sels.insert(II);
+ else
+ CatchAllSels.insert(II);
+ }
+}
+
+/// FindAllURoRInvokes - Find all URoR invokes in the function.
+void DwarfEHPrepare::
+FindAllURoRInvokes(SmallPtrSet<InvokeInst*, 32> &URoRInvokes) {
+ for (Value::use_iterator
+ I = URoR->use_begin(),
+ E = URoR->use_end(); I != E; ++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
+/// initializer instead.
+bool DwarfEHPrepare::CleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels) {
+ if (!EHCatchAllValue) return false;
+
+ if (!SelectorIntrinsic) {
+ SelectorIntrinsic =
+ Intrinsic::getDeclaration(F->getParent(), Intrinsic::eh_selector);
+ if (!SelectorIntrinsic) return false;
+ }
+
+ bool Changed = false;
+ 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->getNumArgOperands() - 1;
+ GlobalVariable *GV = dyn_cast<GlobalVariable>(Sel->getArgOperand(OpIdx));
+ if (GV != EHCatchAllValue) continue;
+ Sel->setArgOperand(OpIdx, EHCatchAllValue->getInitializer());
+ Changed = true;
+ }
+
+ return Changed;
+}
+
+/// FindSelectorAndURoR - Find the eh.selector call associated with the
+/// eh.exception call. And indicate if there is a URoR "invoke" 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
+DwarfEHPrepare::FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
+ 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);
+ if (!II || II->getParent()->getParent() != F) continue;
+
+ if (IntrinsicInst *Sel = dyn_cast<IntrinsicInst>(II)) {
+ if (Sel->getIntrinsicID() == Intrinsic::eh_selector)
+ SelCalls.insert(Sel);
+ } else if (InvokeInst *Invoke = dyn_cast<InvokeInst>(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.
+ } 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);
+ }
+ }
+
+ 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.
+bool DwarfEHPrepare::HandleURoRInvokes() {
+ if (!EHCatchAllValue) {
+ EHCatchAllValue =
+ F->getParent()->getNamedGlobal("llvm.eh.catch.all.value");
+ if (!EHCatchAllValue) return false;
+ }
+
+ if (!SelectorIntrinsic) {
+ SelectorIntrinsic =
+ Intrinsic::getDeclaration(F->getParent(), Intrinsic::eh_selector);
+ if (!SelectorIntrinsic) return false;
+ }
+
+ SmallPtrSet<IntrinsicInst*, 32> Sels;
+ SmallPtrSet<IntrinsicInst*, 32> CatchAllSels;
+ FindAllCleanupSelectors(Sels, CatchAllSels);
+
+ if (!DT)
+ // We require DominatorTree information.
+ return CleanupSelectors(CatchAllSels);
+
+ if (!URoR) {
+ URoR = F->getParent()->getFunction("_Unwind_Resume_or_Rethrow");
+ if (!URoR) return CleanupSelectors(CatchAllSels);
+ }
+
+ SmallPtrSet<InvokeInst*, 32> URoRInvokes;
+ FindAllURoRInvokes(URoRInvokes);
+
+ SmallPtrSet<IntrinsicInst*, 32> SelsToConvert;
+
+ for (SmallPtrSet<IntrinsicInst*, 32>::iterator
+ SI = Sels.begin(), SE = Sels.end(); SI != SE; ++SI) {
+ const BasicBlock *SelBB = (*SI)->getParent();
+ for (SmallPtrSet<InvokeInst*, 32>::iterator
+ UI = URoRInvokes.begin(), UE = URoRInvokes.end(); UI != UE; ++UI) {
+ const BasicBlock *URoRBB = (*UI)->getParent();
+ if (DT->dominates(SelBB, URoRBB)) {
+ SelsToConvert.insert(*SI);
+ break;
+ }
+ }
+ }
+
+ bool Changed = false;
+
+ if (Sels.size() != SelsToConvert.size()) {
+ // If we haven't been able to convert all of the clean-up selectors, then
+ // loop through the slow way to see if they still need to be converted.
+ if (!ExceptionValueIntrinsic) {
+ ExceptionValueIntrinsic =
+ Intrinsic::getDeclaration(F->getParent(), Intrinsic::eh_exception);
+ 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);
+ if (!EHPtr || EHPtr->getParent()->getParent() != F) continue;
+
+ Changed |= PromoteEHPtrStore(EHPtr);
+
+ bool URoRInvoke = false;
+ SmallPtrSet<IntrinsicInst*, 8> SelCalls;
+ Changed |= FindSelectorAndURoR(EHPtr, URoRInvoke, SelCalls);
+
+ 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)
+ if (!HasCatchAllInSelector(*SI))
+ SelsToConvert.insert(*SI);
+ }
+ }
+ }
+
+ if (!SelsToConvert.empty()) {
+ // Convert all clean-up eh.selectors, which are associated with "invokes" of
+ // URoR calls, into catch-all eh.selectors.
+ Changed = true;
+
+ for (SmallPtrSet<IntrinsicInst*, 8>::iterator
+ SI = SelsToConvert.begin(), SE = SelsToConvert.end();
+ SI != SE; ++SI) {
+ IntrinsicInst *II = *SI;
+
+ // Use the exception object pointer and the personality function
+ // from the original selector.
+ 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 =
+ CallInst::Create(SelectorIntrinsic, Args.begin(), Args.end(),
+ "eh.sel.catch.all", II);
+
+ NewSelector->setTailCall(II->isTailCall());
+ NewSelector->setAttributes(II->getAttributes());
+ NewSelector->setCallingConv(II->getCallingConv());
+
+ II->replaceAllUsesWith(NewSelector);
+ II->eraseFromParent();
+ }
+ }
+
+ Changed |= CleanupSelectors(CatchAllSels);
+ return Changed;
}
/// NormalizeLandingPads - Normalize and discover landing pads, noting them
/// in the LandingPads set. A landing pad is normal if the only CFG edges
-/// that end at it are unwind edges from invoke instructions.
+/// that end at it are unwind edges from invoke instructions. If we inlined
+/// through an invoke we could have a normal branch from the previous
+/// unwind block through to the landing pad for the original invoke.
/// Abnormal landing pads are fixed up by redirecting all unwind edges to
/// a new basic block which falls through to the original.
bool DwarfEHPrepare::NormalizeLandingPads() {
bool Changed = false;
+ const MCAsmInfo *MAI = TM->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;
}
}
+
if (OnlyUnwoundTo) {
// Only unwind edges lead to the landing pad. Remember the landing pad.
LandingPads.insert(LPad);
// edges to a new basic block which falls through into this one.
// Create the new basic block.
- BasicBlock *NewBB = BasicBlock::Create(LPad->getName() + "_unwind_edge");
+ BasicBlock *NewBB = BasicBlock::Create(F->getContext(),
+ LPad->getName() + "_unwind_edge");
// Insert it into the function right before the original landing pad.
LPad->getParent()->getBasicBlockList().insert(LPad, NewBB);
/// at runtime if there is no such exception: using unwind to throw a new
/// exception is currently not supported.
bool DwarfEHPrepare::LowerUnwinds() {
- bool Changed = false;
+ SmallVector<TerminatorInst*, 16> UnwindInsts;
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
TerminatorInst *TI = I->getTerminator();
- if (!isa<UnwindInst>(TI))
- continue;
+ if (isa<UnwindInst>(TI))
+ UnwindInsts.push_back(TI);
+ }
+
+ if (UnwindInsts.empty()) return false;
+
+ // Find the rewind function if we didn't already.
+ if (!RewindFunction) {
+ LLVMContext &Ctx = UnwindInsts[0]->getContext();
+ std::vector<const Type*>
+ 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;
// Replace the unwind instruction with a call to _Unwind_Resume (or the
// appropriate target equivalent) followed by an UnreachableInst.
- // Find the rewind function if we didn't already.
- if (!RewindFunction) {
- std::vector<const Type*> Params(1, PointerType::getUnqual(Type::Int8Ty));
- FunctionType *FTy = FunctionType::get(Type::VoidTy, Params, false);
- const char *RewindName = TLI->getLibcallName(RTLIB::UNWIND_RESUME);
- RewindFunction = F->getParent()->getOrInsertFunction(RewindName, FTy);
- }
-
// Create the call...
- CallInst::Create(RewindFunction, CreateReadOfExceptionValue(I), "", TI);
+ CallInst *CI = CallInst::Create(RewindFunction,
+ CreateReadOfExceptionValue(TI->getParent()),
+ "", TI);
+ CI->setCallingConv(TLI->getLibcallCallingConv(RTLIB::UNWIND_RESUME));
// ...followed by an UnreachableInst.
- new UnreachableInst(TI);
+ new UnreachableInst(TI->getContext(), TI);
// Nuke the unwind instruction.
TI->eraseFromParent();
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;
/// the start of the basic block (unless there already is one, in which case
/// the existing call is returned).
Instruction *DwarfEHPrepare::CreateExceptionValueCall(BasicBlock *BB) {
- Instruction *Start = BB->getFirstNonPHI();
+ Instruction *Start = BB->getFirstNonPHIOrDbg();
// Is this a call to eh.exception?
if (IntrinsicInst *CI = dyn_cast<IntrinsicInst>(Start))
if (CI->getIntrinsicID() == Intrinsic::eh_exception)
/// (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->getFirstNonPHI();
+ Instruction *Start = BB->getFirstNonPHIOrDbg();
// Is this a load of the exception temporary?
if (ExceptionValueVar)
if (LoadInst* LI = dyn_cast<LoadInst>(Start))
// Create the temporary if we didn't already.
if (!ExceptionValueVar) {
- ExceptionValueVar = new AllocaInst(
- Context->getPointerTypeUnqual(Type::Int8Ty),
- "eh.value", F->begin()->begin());
+ ExceptionValueVar = new AllocaInst(PointerType::getUnqual(
+ Type::getInt8Ty(BB->getContext())), "eh.value", F->begin()->begin());
++NumStackTempsIntroduced;
}
if (!CompileFast)
Changed |= PromoteStackTemporaries();
+ Changed |= HandleURoRInvokes();
+
LandingPads.clear();
return Changed;
projects / oota-llvm.git / blobdiff