#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/Triple.h"
#include "llvm/ADT/TinyPtrVector.h"
+#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/LibCallSemantics.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/CodeGen/WinEHFuncInfo.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PatternMatch.h"
+#include "llvm/MC/MCSymbol.h"
#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/PromoteMemToReg.h"
+#include "llvm/Transforms/Utils/SSAUpdater.h"
#include <memory>
using namespace llvm;
#define DEBUG_TYPE "winehprepare"
+static cl::opt<bool> DisableDemotion(
+ "disable-demotion", cl::Hidden,
+ cl::desc(
+ "Clone multicolor basic blocks but do not demote cross funclet values"),
+ cl::init(false));
+
+static cl::opt<bool> DisableCleanups(
+ "disable-cleanups", cl::Hidden,
+ cl::desc("Do not remove implausible terminators or other similar cleanups"),
+ cl::init(false));
+
namespace {
// This map is used to model frame variable usage during outlining, to
WinEHPrepare(const TargetMachine *TM = nullptr)
: FunctionPass(ID) {
if (TM)
- TheTriple = Triple(TM->getTargetTriple());
+ TheTriple = TM->getTargetTriple();
}
bool runOnFunction(Function &Fn) override;
LandingPadInst *OutlinedLPad,
const LandingPadInst *OriginalLPad,
FrameVarInfoMap &VarInfo);
- Function *createHandlerFunc(Type *RetTy, const Twine &Name, Module *M,
- Value *&ParentFP);
+ Function *createHandlerFunc(Function *ParentFn, Type *RetTy,
+ const Twine &Name, Module *M, Value *&ParentFP);
bool outlineHandler(ActionHandler *Action, Function *SrcFn,
LandingPadInst *LPad, BasicBlock *StartBB,
FrameVarInfoMap &VarInfo);
BasicBlock *EndBB);
void processSEHCatchHandler(CatchHandler *Handler, BasicBlock *StartBB);
+ void insertPHIStores(PHINode *OriginalPHI, AllocaInst *SpillSlot);
+ void
+ insertPHIStore(BasicBlock *PredBlock, Value *PredVal, AllocaInst *SpillSlot,
+ SmallVectorImpl<std::pair<BasicBlock *, Value *>> &Worklist);
+ AllocaInst *insertPHILoads(PHINode *PN, Function &F);
+ void replaceUseWithLoad(Value *V, Use &U, AllocaInst *&SpillSlot,
+ DenseMap<BasicBlock *, Value *> &Loads, Function &F);
+ void demoteNonlocalUses(Value *V, std::set<BasicBlock *> &ColorsForBB,
+ Function &F);
+ bool prepareExplicitEH(Function &F,
+ SmallVectorImpl<BasicBlock *> &EntryBlocks);
+ void replaceTerminatePadWithCleanup(Function &F);
+ void colorFunclets(Function &F, SmallVectorImpl<BasicBlock *> &EntryBlocks);
+ void demotePHIsOnFunclets(Function &F);
+ void demoteUsesBetweenFunclets(Function &F);
+ void demoteArgumentUses(Function &F);
+ void cloneCommonBlocks(Function &F,
+ SmallVectorImpl<BasicBlock *> &EntryBlocks);
+ void removeImplausibleTerminators(Function &F);
+ void cleanupPreparedFunclets(Function &F);
+ void verifyPreparedFunclets(Function &F);
Triple TheTriple;
// outlined but before the outlined code is pruned from the parent function.
DenseMap<const BasicBlock *, BasicBlock *> LPadTargetBlocks;
- // Map from outlined handler to call to llvm.frameaddress(1). Only used for
+ // Map from outlined handler to call to parent local address. Only used for
// 32-bit EH.
DenseMap<Function *, Value *> HandlerToParentFP;
AllocaInst *SEHExceptionCodeSlot = nullptr;
+
+ std::map<BasicBlock *, std::set<BasicBlock *>> BlockColors;
+ std::map<BasicBlock *, std::set<BasicBlock *>> FuncletBlocks;
+ std::map<BasicBlock *, std::set<BasicBlock *>> FuncletChildren;
};
class WinEHFrameVariableMaterializer : public ValueMaterializer {
return new WinEHPrepare(TM);
}
-bool WinEHPrepare::runOnFunction(Function &Fn) {
- // No need to prepare outlined handlers.
- if (Fn.hasFnAttribute("wineh-parent"))
- return false;
-
- SmallVector<LandingPadInst *, 4> LPads;
- SmallVector<ResumeInst *, 4> Resumes;
+static bool
+findExceptionalConstructs(Function &Fn,
+ SmallVectorImpl<LandingPadInst *> &LPads,
+ SmallVectorImpl<ResumeInst *> &Resumes,
+ SmallVectorImpl<BasicBlock *> &EntryBlocks) {
+ bool ForExplicitEH = false;
for (BasicBlock &BB : Fn) {
- if (auto *LP = BB.getLandingPadInst())
+ Instruction *First = BB.getFirstNonPHI();
+ if (auto *LP = dyn_cast<LandingPadInst>(First)) {
LPads.push_back(LP);
+ } else if (First->isEHPad()) {
+ if (!ForExplicitEH)
+ EntryBlocks.push_back(&Fn.getEntryBlock());
+ if (!isa<CatchEndPadInst>(First) && !isa<CleanupEndPadInst>(First))
+ EntryBlocks.push_back(&BB);
+ ForExplicitEH = true;
+ }
if (auto *Resume = dyn_cast<ResumeInst>(BB.getTerminator()))
Resumes.push_back(Resume);
}
+ return ForExplicitEH;
+}
- // No need to prepare functions that lack landing pads.
- if (LPads.empty())
+bool WinEHPrepare::runOnFunction(Function &Fn) {
+ if (!Fn.hasPersonalityFn())
+ return false;
+
+ // No need to prepare outlined handlers.
+ if (Fn.hasFnAttribute("wineh-parent"))
return false;
// Classify the personality to see what kind of preparation we need.
Personality = classifyEHPersonality(Fn.getPersonalityFn());
- // Do nothing if this is not an MSVC personality.
- if (!isMSVCEHPersonality(Personality))
+ // Do nothing if this is not a funclet-based personality.
+ if (!isFuncletEHPersonality(Personality))
+ return false;
+
+ SmallVector<LandingPadInst *, 4> LPads;
+ SmallVector<ResumeInst *, 4> Resumes;
+ SmallVector<BasicBlock *, 4> EntryBlocks;
+ bool ForExplicitEH =
+ findExceptionalConstructs(Fn, LPads, Resumes, EntryBlocks);
+
+ if (ForExplicitEH)
+ return prepareExplicitEH(Fn, EntryBlocks);
+
+ // No need to prepare functions that lack landing pads.
+ if (LPads.empty())
return false;
DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
BasicBlock *NextBB;
Constant *Selector;
if (isSelectorDispatch(BB, CatchHandler, Selector, NextBB)) {
- // Split the edge if there is a phi node. Returning from EH to a phi node
- // is just as impossible as having a phi after an indirectbr.
- if (isa<PHINode>(CatchHandler->begin())) {
+ // Split the edge if there are multiple predecessors. This creates a place
+ // where we can insert EH recovery code.
+ if (!CatchHandler->getSinglePredecessor()) {
DEBUG(dbgs() << "splitting EH return edge from " << BB->getName()
<< " to " << CatchHandler->getName() << '\n');
BBI = CatchHandler = SplitCriticalEdge(
// identifyEHBlocks() should have been called before this function.
assert(!NormalBlocks.empty());
+ // Try to avoid demoting EH pointer and selector values. They get in the way
+ // of our pattern matching.
+ SmallPtrSet<Instruction *, 10> EHVals;
+ for (BasicBlock &BB : F) {
+ LandingPadInst *LP = BB.getLandingPadInst();
+ if (!LP)
+ continue;
+ EHVals.insert(LP);
+ for (User *U : LP->users()) {
+ auto *EI = dyn_cast<ExtractValueInst>(U);
+ if (!EI)
+ continue;
+ EHVals.insert(EI);
+ for (User *U2 : EI->users()) {
+ if (auto *PN = dyn_cast<PHINode>(U2))
+ EHVals.insert(PN);
+ }
+ }
+ }
+
SetVector<Argument *> ArgsToDemote;
SetVector<Instruction *> InstrsToDemote;
for (BasicBlock &BB : F) {
continue;
}
+ // Don't demote EH values.
auto *OpI = cast<Instruction>(Op);
+ if (EHVals.count(OpI))
+ continue;
+
BasicBlock *OpBB = OpI->getParent();
// If a value is produced and consumed in the same BB, we don't need to
// demote it.
LPad->replaceAllUsesWith(UndefValue::get(LPad->getType()));
// Rewrite uses of the exception pointer to loads of an alloca.
- for (Instruction *E : SEHCodeUses) {
+ while (!SEHCodeUses.empty()) {
+ Instruction *E = SEHCodeUses.pop_back_val();
SmallVector<Use *, 4> Uses;
for (Use &U : E->uses())
Uses.push_back(&U);
auto *I = cast<Instruction>(U->getUser());
if (isa<ResumeInst>(I))
continue;
- LoadInst *LI;
if (auto *Phi = dyn_cast<PHINode>(I))
- LI = new LoadInst(SEHExceptionCodeSlot, "sehcode", false,
- Phi->getIncomingBlock(*U));
+ SEHCodeUses.push_back(Phi);
else
- LI = new LoadInst(SEHExceptionCodeSlot, "sehcode", false, I);
- U->set(LI);
+ U->set(new LoadInst(SEHExceptionCodeSlot, "sehcode", false, I));
}
E->replaceAllUsesWith(UndefValue::get(E->getType()));
E->eraseFromParent();
Builder.SetInsertPoint(Entry->getFirstInsertionPt());
Function *FrameEscapeFn =
- Intrinsic::getDeclaration(M, Intrinsic::frameescape);
+ Intrinsic::getDeclaration(M, Intrinsic::localescape);
Function *RecoverFrameFn =
- Intrinsic::getDeclaration(M, Intrinsic::framerecover);
+ Intrinsic::getDeclaration(M, Intrinsic::localrecover);
SmallVector<Value *, 8> AllocasToEscape;
- // Scan the entry block for an existing call to llvm.frameescape. We need to
+ // Scan the entry block for an existing call to llvm.localescape. We need to
// keep escaping those objects.
for (Instruction &I : F.front()) {
auto *II = dyn_cast<IntrinsicInst>(&I);
- if (II && II->getIntrinsicID() == Intrinsic::frameescape) {
+ if (II && II->getIntrinsicID() == Intrinsic::localescape) {
auto Args = II->arg_operands();
AllocasToEscape.append(Args.begin(), Args.end());
II->eraseFromParent();
}
// Finally, replace all of the temporary allocas for frame variables used in
- // the outlined handlers with calls to llvm.framerecover.
+ // the outlined handlers with calls to llvm.localrecover.
for (auto &VarInfoEntry : FrameVarInfo) {
Value *ParentVal = VarInfoEntry.first;
TinyPtrVector<AllocaInst *> &Allocas = VarInfoEntry.second;
llvm::Value *FP = HandlerToParentFP[HandlerFn];
assert(FP);
- // FIXME: Sink this framerecover into the blocks where it is used.
+ // FIXME: Sink this localrecover into the blocks where it is used.
Builder.SetInsertPoint(TempAlloca);
Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc());
Value *RecoverArgs[] = {
}
} // End for each FrameVarInfo entry.
- // Insert 'call void (...)* @llvm.frameescape(...)' at the end of the entry
+ // Insert 'call void (...)* @llvm.localescape(...)' at the end of the entry
// block.
Builder.SetInsertPoint(&F.getEntryBlock().back());
Builder.CreateCall(FrameEscapeFn, AllocasToEscape);
// FIXME: Consider sinking this into lib/Target/X86 somehow. TargetLowering
// usually doesn't build LLVM IR, so that's probably the wrong place.
-Function *WinEHPrepare::createHandlerFunc(Type *RetTy, const Twine &Name,
- Module *M, Value *&ParentFP) {
+Function *WinEHPrepare::createHandlerFunc(Function *ParentFn, Type *RetTy,
+ const Twine &Name, Module *M,
+ Value *&ParentFP) {
// x64 uses a two-argument prototype where the parent FP is the second
// argument. x86 uses no arguments, just the incoming EBP value.
LLVMContext &Context = M->getContext();
+ Type *Int8PtrType = Type::getInt8PtrTy(Context);
FunctionType *FnType;
if (TheTriple.getArch() == Triple::x86_64) {
- Type *Int8PtrType = Type::getInt8PtrTy(Context);
Type *ArgTys[2] = {Int8PtrType, Int8PtrType};
FnType = FunctionType::get(RetTy, ArgTys, false);
} else {
assert(M);
Function *FrameAddressFn =
Intrinsic::getDeclaration(M, Intrinsic::frameaddress);
- Value *Args[1] = {ConstantInt::get(Type::getInt32Ty(Context), 1)};
- ParentFP = CallInst::Create(FrameAddressFn, Args, "parent_fp",
- &Handler->getEntryBlock());
+ Function *RecoverFPFn =
+ Intrinsic::getDeclaration(M, Intrinsic::x86_seh_recoverfp);
+ IRBuilder<> Builder(&Handler->getEntryBlock());
+ Value *EBP =
+ Builder.CreateCall(FrameAddressFn, {Builder.getInt32(1)}, "ebp");
+ Value *ParentI8Fn = Builder.CreateBitCast(ParentFn, Int8PtrType);
+ ParentFP = Builder.CreateCall(RecoverFPFn, {ParentI8Fn, EBP});
}
return Handler;
}
Value *ParentFP;
Function *Handler;
if (Action->getType() == Catch) {
- Handler = createHandlerFunc(Int8PtrType, SrcFn->getName() + ".catch", M,
+ Handler = createHandlerFunc(SrcFn, Int8PtrType, SrcFn->getName() + ".catch", M,
ParentFP);
} else {
- Handler = createHandlerFunc(Type::getVoidTy(Context),
+ Handler = createHandlerFunc(SrcFn, Type::getVoidTy(Context),
SrcFn->getName() + ".cleanup", M, ParentFP);
}
Handler->setPersonalityFn(SrcFn->getPersonalityFn());
VMap[Extract] = SelectorValue;
}
-static bool isFrameAddressCall(const Value *V) {
- return match(const_cast<Value *>(V),
- m_Intrinsic<Intrinsic::frameaddress>(m_SpecificInt(0)));
+static bool isLocalAddressCall(const Value *V) {
+ return match(const_cast<Value *>(V), m_Intrinsic<Intrinsic::localaddress>());
}
CloningDirector::CloningAction WinEHCloningDirectorBase::handleInstruction(
if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>()))
return handleTypeIdFor(VMap, Inst, NewBB);
- // When outlining llvm.frameaddress(i32 0), remap that to the second argument,
+ // When outlining llvm.localaddress(), remap that to the second argument,
// which is the FP of the parent.
- if (isFrameAddressCall(Inst)) {
+ if (isLocalAddressCall(Inst)) {
VMap[Inst] = ParentFP;
return CloningDirector::SkipInstruction;
}
// If we're asked to materialize a static alloca, we temporarily create an
// alloca in the outlined function and add this to the FrameVarInfo map. When
// all the outlining is complete, we'll replace these temporary allocas with
- // calls to llvm.framerecover.
+ // calls to llvm.localrecover.
if (auto *AV = dyn_cast<AllocaInst>(V)) {
assert(AV->isStaticAlloca() &&
"cannot materialize un-demoted dynamic alloca");
// of a catch parameter, add a sentinel to the multimap to indicate that it's
// used from another handler. This will prevent us from trying to sink the
// alloca into the handler and ensure that the catch parameter is present in
- // the call to llvm.frameescape.
+ // the call to llvm.localescape.
FrameVarInfo[V].push_back(getCatchObjectSentinel());
}
// Under some circumstances optimized IR will flow unconditionally into a
// handler block without checking the selector. This can only happen if
// the landing pad has a catch-all handler and the handler for the
- // preceeding catch clause is identical to the catch-call handler
+ // preceding catch clause is identical to the catch-call handler
// (typically an empty catch). In this case, the handler must be shared
// by all remaining clauses.
if (isa<ConstantPointerNull>(
static CallSite matchOutlinedFinallyCall(BasicBlock *BB,
Instruction *MaybeCall) {
// Look for finally blocks that Clang has already outlined for us.
- // %fp = call i8* @llvm.frameaddress(i32 0)
+ // %fp = call i8* @llvm.localaddress()
// call void @"fin$parent"(iN 1, i8* %fp)
- if (isFrameAddressCall(MaybeCall) && MaybeCall != BB->getTerminator())
+ if (isLocalAddressCall(MaybeCall) && MaybeCall != BB->getTerminator())
MaybeCall = MaybeCall->getNextNode();
CallSite FinallyCall(MaybeCall);
if (!FinallyCall || FinallyCall.arg_size() != 2)
return CallSite();
if (!match(FinallyCall.getArgument(0), m_SpecificInt(1)))
return CallSite();
- if (!isFrameAddressCall(FinallyCall.getArgument(1)))
+ if (!isLocalAddressCall(FinallyCall.getArgument(1)))
return CallSite();
return FinallyCall;
}
// value for this block but the value is a nullptr. This means that
// we have previously analyzed the block and determined that it did
// not contain any cleanup code. Based on the earlier analysis, we
- // know the the block must end in either an unconditional branch, a
+ // know the block must end in either an unconditional branch, a
// resume or a conditional branch that is predicated on a comparison
// with a selector. Either the resume or the selector dispatch
// would terminate the search for cleanup code, so the unconditional
MaybeCall = MaybeCall->getNextNode();
}
- // Look for outlined finally calls.
- if (CallSite FinallyCall = matchOutlinedFinallyCall(BB, MaybeCall)) {
- Function *Fin = FinallyCall.getCalledFunction();
- assert(Fin && "outlined finally call should be direct");
- auto *Action = new CleanupHandler(BB);
- Action->setHandlerBlockOrFunc(Fin);
- Actions.insertCleanupHandler(Action);
- CleanupHandlerMap[BB] = Action;
- DEBUG(dbgs() << " Found frontend-outlined finally call to "
- << Fin->getName() << " in block "
- << Action->getStartBlock()->getName() << "\n");
-
- // Split the block if there were more interesting instructions and look
- // for finally calls in the normal successor block.
- BasicBlock *SuccBB = BB;
- if (FinallyCall.getInstruction() != BB->getTerminator() &&
- FinallyCall.getInstruction()->getNextNode() !=
- BB->getTerminator()) {
- SuccBB =
- SplitBlock(BB, FinallyCall.getInstruction()->getNextNode(), DT);
- } else {
- if (FinallyCall.isInvoke()) {
+ // Look for outlined finally calls on x64, since those happen to match the
+ // prototype provided by the runtime.
+ if (TheTriple.getArch() == Triple::x86_64) {
+ if (CallSite FinallyCall = matchOutlinedFinallyCall(BB, MaybeCall)) {
+ Function *Fin = FinallyCall.getCalledFunction();
+ assert(Fin && "outlined finally call should be direct");
+ auto *Action = new CleanupHandler(BB);
+ Action->setHandlerBlockOrFunc(Fin);
+ Actions.insertCleanupHandler(Action);
+ CleanupHandlerMap[BB] = Action;
+ DEBUG(dbgs() << " Found frontend-outlined finally call to "
+ << Fin->getName() << " in block "
+ << Action->getStartBlock()->getName() << "\n");
+
+ // Split the block if there were more interesting instructions and
+ // look for finally calls in the normal successor block.
+ BasicBlock *SuccBB = BB;
+ if (FinallyCall.getInstruction() != BB->getTerminator() &&
+ FinallyCall.getInstruction()->getNextNode() !=
+ BB->getTerminator()) {
SuccBB =
- cast<InvokeInst>(FinallyCall.getInstruction())->getNormalDest();
+ SplitBlock(BB, FinallyCall.getInstruction()->getNextNode(), DT);
} else {
- SuccBB = BB->getUniqueSuccessor();
- assert(SuccBB &&
- "splitOutlinedFinallyCalls didn't insert a branch");
+ if (FinallyCall.isInvoke()) {
+ SuccBB = cast<InvokeInst>(FinallyCall.getInstruction())
+ ->getNormalDest();
+ } else {
+ SuccBB = BB->getUniqueSuccessor();
+ assert(SuccBB &&
+ "splitOutlinedFinallyCalls didn't insert a branch");
+ }
}
+ BB = SuccBB;
+ if (BB == EndBB)
+ return;
+ continue;
}
- BB = SuccBB;
- if (BB == EndBB)
- return;
- continue;
}
}
std::reverse(Actions.begin(), Actions.end());
}
-namespace {
-struct WinEHNumbering {
- WinEHNumbering(WinEHFuncInfo &FuncInfo) : FuncInfo(FuncInfo),
- CurrentBaseState(-1), NextState(0) {}
+static int addUnwindMapEntry(WinEHFuncInfo &FuncInfo, int ToState,
+ const Value *V) {
+ WinEHUnwindMapEntry UME;
+ UME.ToState = ToState;
+ UME.Cleanup = V;
+ FuncInfo.UnwindMap.push_back(UME);
+ return FuncInfo.getLastStateNumber();
+}
+
+static void addTryBlockMapEntry(WinEHFuncInfo &FuncInfo, int TryLow,
+ int TryHigh, int CatchHigh,
+ ArrayRef<const CatchPadInst *> Handlers) {
+ WinEHTryBlockMapEntry TBME;
+ TBME.TryLow = TryLow;
+ TBME.TryHigh = TryHigh;
+ TBME.CatchHigh = CatchHigh;
+ assert(TBME.TryLow <= TBME.TryHigh);
+ for (const CatchPadInst *CPI : Handlers) {
+ WinEHHandlerType HT;
+ Constant *TypeInfo = cast<Constant>(CPI->getArgOperand(0));
+ if (TypeInfo->isNullValue())
+ HT.TypeDescriptor = nullptr;
+ else
+ HT.TypeDescriptor = cast<GlobalVariable>(TypeInfo->stripPointerCasts());
+ HT.Adjectives = cast<ConstantInt>(CPI->getArgOperand(1))->getZExtValue();
+ HT.Handler = CPI->getNormalDest();
+ HT.CatchObjRecoverIdx = -2;
+ if (isa<ConstantPointerNull>(CPI->getArgOperand(2)))
+ HT.CatchObj.Alloca = nullptr;
+ else
+ HT.CatchObj.Alloca = cast<AllocaInst>(CPI->getArgOperand(2));
+ TBME.HandlerArray.push_back(HT);
+ }
+ FuncInfo.TryBlockMap.push_back(TBME);
+}
+
+static const CatchPadInst *getSingleCatchPadPredecessor(const BasicBlock *BB) {
+ for (const BasicBlock *PredBlock : predecessors(BB))
+ if (auto *CPI = dyn_cast<CatchPadInst>(PredBlock->getFirstNonPHI()))
+ return CPI;
+ return nullptr;
+}
+
+/// Find all the catchpads that feed directly into the catchendpad. Frontends
+/// using this personality should ensure that each catchendpad and catchpad has
+/// one or zero catchpad predecessors.
+///
+/// The following C++ generates the IR after it:
+/// try {
+/// } catch (A) {
+/// } catch (B) {
+/// }
+///
+/// IR:
+/// %catchpad.A
+/// catchpad [i8* A typeinfo]
+/// to label %catch.A unwind label %catchpad.B
+/// %catchpad.B
+/// catchpad [i8* B typeinfo]
+/// to label %catch.B unwind label %endcatches
+/// %endcatches
+/// catchendblock unwind to caller
+static void
+findCatchPadsForCatchEndPad(const BasicBlock *CatchEndBB,
+ SmallVectorImpl<const CatchPadInst *> &Handlers) {
+ const CatchPadInst *CPI = getSingleCatchPadPredecessor(CatchEndBB);
+ while (CPI) {
+ Handlers.push_back(CPI);
+ CPI = getSingleCatchPadPredecessor(CPI->getParent());
+ }
+ // We've pushed these back into reverse source order. Reverse them to get
+ // the list back into source order.
+ std::reverse(Handlers.begin(), Handlers.end());
+}
- WinEHFuncInfo &FuncInfo;
- int CurrentBaseState;
- int NextState;
+// Given BB which ends in an unwind edge, return the EHPad that this BB belongs
+// to. If the unwind edge came from an invoke, return null.
+static const BasicBlock *getEHPadFromPredecessor(const BasicBlock *BB) {
+ const TerminatorInst *TI = BB->getTerminator();
+ if (isa<InvokeInst>(TI))
+ return nullptr;
+ if (TI->isEHPad())
+ return BB;
+ return cast<CleanupReturnInst>(TI)->getCleanupPad()->getParent();
+}
- SmallVector<std::unique_ptr<ActionHandler>, 4> HandlerStack;
- SmallPtrSet<const Function *, 4> VisitedHandlers;
+static void calculateExplicitCXXStateNumbers(WinEHFuncInfo &FuncInfo,
+ const BasicBlock &BB,
+ int ParentState) {
+ assert(BB.isEHPad());
+ const Instruction *FirstNonPHI = BB.getFirstNonPHI();
+ // All catchpad instructions will be handled when we process their
+ // respective catchendpad instruction.
+ if (isa<CatchPadInst>(FirstNonPHI))
+ return;
- int currentEHNumber() const {
- return HandlerStack.empty() ? CurrentBaseState : HandlerStack.back()->getEHState();
+ if (isa<CatchEndPadInst>(FirstNonPHI)) {
+ SmallVector<const CatchPadInst *, 2> Handlers;
+ findCatchPadsForCatchEndPad(&BB, Handlers);
+ const BasicBlock *FirstTryPad = Handlers.front()->getParent();
+ int TryLow = addUnwindMapEntry(FuncInfo, ParentState, nullptr);
+ FuncInfo.EHPadStateMap[Handlers.front()] = TryLow;
+ for (const BasicBlock *PredBlock : predecessors(FirstTryPad))
+ if ((PredBlock = getEHPadFromPredecessor(PredBlock)))
+ calculateExplicitCXXStateNumbers(FuncInfo, *PredBlock, TryLow);
+ int CatchLow = addUnwindMapEntry(FuncInfo, ParentState, nullptr);
+
+ // catchpads are separate funclets in C++ EH due to the way rethrow works.
+ // In SEH, they aren't, so no invokes will unwind to the catchendpad.
+ FuncInfo.EHPadStateMap[FirstNonPHI] = CatchLow;
+ int TryHigh = CatchLow - 1;
+ for (const BasicBlock *PredBlock : predecessors(&BB))
+ if ((PredBlock = getEHPadFromPredecessor(PredBlock)))
+ calculateExplicitCXXStateNumbers(FuncInfo, *PredBlock, CatchLow);
+ int CatchHigh = FuncInfo.getLastStateNumber();
+ addTryBlockMapEntry(FuncInfo, TryLow, TryHigh, CatchHigh, Handlers);
+ DEBUG(dbgs() << "TryLow[" << FirstTryPad->getName() << "]: " << TryLow
+ << '\n');
+ DEBUG(dbgs() << "TryHigh[" << FirstTryPad->getName() << "]: " << TryHigh
+ << '\n');
+ DEBUG(dbgs() << "CatchHigh[" << FirstTryPad->getName() << "]: " << CatchHigh
+ << '\n');
+ } else if (isa<CleanupPadInst>(FirstNonPHI)) {
+ int CleanupState = addUnwindMapEntry(FuncInfo, ParentState, &BB);
+ FuncInfo.EHPadStateMap[FirstNonPHI] = CleanupState;
+ DEBUG(dbgs() << "Assigning state #" << CleanupState << " to BB "
+ << BB.getName() << '\n');
+ for (const BasicBlock *PredBlock : predecessors(&BB))
+ if ((PredBlock = getEHPadFromPredecessor(PredBlock)))
+ calculateExplicitCXXStateNumbers(FuncInfo, *PredBlock, CleanupState);
+ } else if (isa<TerminatePadInst>(FirstNonPHI)) {
+ report_fatal_error("Not yet implemented!");
+ } else {
+ llvm_unreachable("unexpected EH Pad!");
}
+}
- void createUnwindMapEntry(int ToState, ActionHandler *AH);
- void createTryBlockMapEntry(int TryLow, int TryHigh,
- ArrayRef<CatchHandler *> Handlers);
- void processCallSite(MutableArrayRef<std::unique_ptr<ActionHandler>> Actions,
- ImmutableCallSite CS);
- void popUnmatchedActions(int FirstMismatch);
- void calculateStateNumbers(const Function &F);
- void findActionRootLPads(const Function &F);
-};
+static int addSEHExcept(WinEHFuncInfo &FuncInfo, int ParentState,
+ const Function *Filter, const BasicBlock *Handler) {
+ SEHUnwindMapEntry Entry;
+ Entry.ToState = ParentState;
+ Entry.IsFinally = false;
+ Entry.Filter = Filter;
+ Entry.Handler = Handler;
+ FuncInfo.SEHUnwindMap.push_back(Entry);
+ return FuncInfo.SEHUnwindMap.size() - 1;
}
-void WinEHNumbering::createUnwindMapEntry(int ToState, ActionHandler *AH) {
- WinEHUnwindMapEntry UME;
- UME.ToState = ToState;
- if (auto *CH = dyn_cast_or_null<CleanupHandler>(AH))
- UME.Cleanup = cast<Function>(CH->getHandlerBlockOrFunc());
- else
- UME.Cleanup = nullptr;
- FuncInfo.UnwindMap.push_back(UME);
+static int addSEHFinally(WinEHFuncInfo &FuncInfo, int ParentState,
+ const BasicBlock *Handler) {
+ SEHUnwindMapEntry Entry;
+ Entry.ToState = ParentState;
+ Entry.IsFinally = true;
+ Entry.Filter = nullptr;
+ Entry.Handler = Handler;
+ FuncInfo.SEHUnwindMap.push_back(Entry);
+ return FuncInfo.SEHUnwindMap.size() - 1;
+}
+
+static void calculateExplicitSEHStateNumbers(WinEHFuncInfo &FuncInfo,
+ const BasicBlock &BB,
+ int ParentState) {
+ assert(BB.isEHPad());
+ const Instruction *FirstNonPHI = BB.getFirstNonPHI();
+ // All catchpad instructions will be handled when we process their
+ // respective catchendpad instruction.
+ if (isa<CatchPadInst>(FirstNonPHI))
+ return;
+
+ if (isa<CatchEndPadInst>(FirstNonPHI)) {
+ // Extract the filter function and the __except basic block and create a
+ // state for them.
+ SmallVector<const CatchPadInst *, 1> Handlers;
+ findCatchPadsForCatchEndPad(&BB, Handlers);
+ assert(Handlers.size() == 1 &&
+ "SEH doesn't have multiple handlers per __try");
+ const CatchPadInst *CPI = Handlers.front();
+ const BasicBlock *CatchPadBB = CPI->getParent();
+ const Constant *FilterOrNull =
+ cast<Constant>(CPI->getArgOperand(0)->stripPointerCasts());
+ const Function *Filter = dyn_cast<Function>(FilterOrNull);
+ assert((Filter || FilterOrNull->isNullValue()) &&
+ "unexpected filter value");
+ int TryState =
+ addSEHExcept(FuncInfo, ParentState, Filter, CPI->getNormalDest());
+
+ // Everything in the __try block uses TryState as its parent state.
+ FuncInfo.EHPadStateMap[CPI] = TryState;
+ DEBUG(dbgs() << "Assigning state #" << TryState << " to BB "
+ << CatchPadBB->getName() << '\n');
+ for (const BasicBlock *PredBlock : predecessors(CatchPadBB))
+ if ((PredBlock = getEHPadFromPredecessor(PredBlock)))
+ calculateExplicitSEHStateNumbers(FuncInfo, *PredBlock, TryState);
+
+ // Everything in the __except block unwinds to ParentState, just like code
+ // outside the __try.
+ FuncInfo.EHPadStateMap[FirstNonPHI] = ParentState;
+ DEBUG(dbgs() << "Assigning state #" << ParentState << " to BB "
+ << BB.getName() << '\n');
+ for (const BasicBlock *PredBlock : predecessors(&BB))
+ if ((PredBlock = getEHPadFromPredecessor(PredBlock)))
+ calculateExplicitSEHStateNumbers(FuncInfo, *PredBlock, ParentState);
+ } else if (isa<CleanupPadInst>(FirstNonPHI)) {
+ int CleanupState = addSEHFinally(FuncInfo, ParentState, &BB);
+ FuncInfo.EHPadStateMap[FirstNonPHI] = CleanupState;
+ DEBUG(dbgs() << "Assigning state #" << CleanupState << " to BB "
+ << BB.getName() << '\n');
+ for (const BasicBlock *PredBlock : predecessors(&BB))
+ if ((PredBlock = getEHPadFromPredecessor(PredBlock)))
+ calculateExplicitSEHStateNumbers(FuncInfo, *PredBlock, CleanupState);
+ } else if (isa<CleanupEndPadInst>(FirstNonPHI)) {
+ // Anything unwinding through CleanupEndPadInst is in ParentState.
+ FuncInfo.EHPadStateMap[FirstNonPHI] = ParentState;
+ DEBUG(dbgs() << "Assigning state #" << ParentState << " to BB "
+ << BB.getName() << '\n');
+ for (const BasicBlock *PredBlock : predecessors(&BB))
+ if ((PredBlock = getEHPadFromPredecessor(PredBlock)))
+ calculateExplicitSEHStateNumbers(FuncInfo, *PredBlock, ParentState);
+ } else if (isa<TerminatePadInst>(FirstNonPHI)) {
+ report_fatal_error("Not yet implemented!");
+ } else {
+ llvm_unreachable("unexpected EH Pad!");
+ }
}
-void WinEHNumbering::createTryBlockMapEntry(int TryLow, int TryHigh,
- ArrayRef<CatchHandler *> Handlers) {
- // See if we already have an entry for this set of handlers.
- // This is using iterators rather than a range-based for loop because
- // if we find the entry we're looking for we'll need the iterator to erase it.
- int NumHandlers = Handlers.size();
- auto I = FuncInfo.TryBlockMap.begin();
- auto E = FuncInfo.TryBlockMap.end();
- for ( ; I != E; ++I) {
- auto &Entry = *I;
- if (Entry.HandlerArray.size() != (size_t)NumHandlers)
+/// Check if the EH Pad unwinds to caller. Cleanups are a little bit of a
+/// special case because we have to look at the cleanupret instruction that uses
+/// the cleanuppad.
+static bool doesEHPadUnwindToCaller(const Instruction *EHPad) {
+ auto *CPI = dyn_cast<CleanupPadInst>(EHPad);
+ if (!CPI)
+ return EHPad->mayThrow();
+
+ // This cleanup does not return or unwind, so we say it unwinds to caller.
+ if (CPI->use_empty())
+ return true;
+
+ const Instruction *User = CPI->user_back();
+ if (auto *CRI = dyn_cast<CleanupReturnInst>(User))
+ return CRI->unwindsToCaller();
+ return cast<CleanupEndPadInst>(User)->unwindsToCaller();
+}
+
+void llvm::calculateSEHStateNumbers(const Function *Fn,
+ WinEHFuncInfo &FuncInfo) {
+ // Don't compute state numbers twice.
+ if (!FuncInfo.SEHUnwindMap.empty())
+ return;
+
+ for (const BasicBlock &BB : *Fn) {
+ if (!BB.isEHPad() || !doesEHPadUnwindToCaller(BB.getFirstNonPHI()))
continue;
- int N;
- for (N = 0; N < NumHandlers; ++N) {
- if (Entry.HandlerArray[N].Handler != Handlers[N]->getHandlerBlockOrFunc())
- break; // breaks out of inner loop
- }
- // If all the handlers match, this is what we were looking for.
- if (N == NumHandlers) {
- break;
- }
+ calculateExplicitSEHStateNumbers(FuncInfo, BB, -1);
}
+}
- // If we found an existing entry for this set of handlers, extend the range
- // but move the entry to the end of the map vector. The order of entries
- // in the map is critical to the way that the runtime finds handlers.
- // FIXME: Depending on what has happened with block ordering, this may
- // incorrectly combine entries that should remain separate.
- if (I != E) {
- // Copy the existing entry.
- WinEHTryBlockMapEntry Entry = *I;
- Entry.TryLow = std::min(TryLow, Entry.TryLow);
- Entry.TryHigh = std::max(TryHigh, Entry.TryHigh);
- assert(Entry.TryLow <= Entry.TryHigh);
- // Erase the old entry and add this one to the back.
- FuncInfo.TryBlockMap.erase(I);
- FuncInfo.TryBlockMap.push_back(Entry);
+void llvm::calculateWinCXXEHStateNumbers(const Function *Fn,
+ WinEHFuncInfo &FuncInfo) {
+ // Return if it's already been done.
+ if (!FuncInfo.EHPadStateMap.empty())
return;
+
+ for (const BasicBlock &BB : *Fn) {
+ if (!BB.isEHPad())
+ continue;
+ if (BB.isLandingPad())
+ report_fatal_error("MSVC C++ EH cannot use landingpads");
+ const Instruction *FirstNonPHI = BB.getFirstNonPHI();
+ // Skip cleanupendpads; they are exits, not entries.
+ if (isa<CleanupEndPadInst>(FirstNonPHI))
+ continue;
+ if (!doesEHPadUnwindToCaller(FirstNonPHI))
+ continue;
+ calculateExplicitCXXStateNumbers(FuncInfo, BB, -1);
}
+}
- // If we didn't find an entry, create a new one.
- WinEHTryBlockMapEntry TBME;
- TBME.TryLow = TryLow;
- TBME.TryHigh = TryHigh;
- assert(TBME.TryLow <= TBME.TryHigh);
- for (CatchHandler *CH : Handlers) {
- WinEHHandlerType HT;
- if (CH->getSelector()->isNullValue()) {
- HT.Adjectives = 0x40;
- HT.TypeDescriptor = nullptr;
+static int addClrEHHandler(WinEHFuncInfo &FuncInfo, int ParentState,
+ ClrHandlerType HandlerType, uint32_t TypeToken,
+ const BasicBlock *Handler) {
+ ClrEHUnwindMapEntry Entry;
+ Entry.Parent = ParentState;
+ Entry.Handler = Handler;
+ Entry.HandlerType = HandlerType;
+ Entry.TypeToken = TypeToken;
+ FuncInfo.ClrEHUnwindMap.push_back(Entry);
+ return FuncInfo.ClrEHUnwindMap.size() - 1;
+}
+
+void llvm::calculateClrEHStateNumbers(const Function *Fn,
+ WinEHFuncInfo &FuncInfo) {
+ // Return if it's already been done.
+ if (!FuncInfo.EHPadStateMap.empty())
+ return;
+
+ SmallVector<std::pair<const Instruction *, int>, 8> Worklist;
+
+ // Each pad needs to be able to refer to its parent, so scan the function
+ // looking for top-level handlers and seed the worklist with them.
+ for (const BasicBlock &BB : *Fn) {
+ if (!BB.isEHPad())
+ continue;
+ if (BB.isLandingPad())
+ report_fatal_error("CoreCLR EH cannot use landingpads");
+ const Instruction *FirstNonPHI = BB.getFirstNonPHI();
+ if (!doesEHPadUnwindToCaller(FirstNonPHI))
+ continue;
+ // queue this with sentinel parent state -1 to mean unwind to caller.
+ Worklist.emplace_back(FirstNonPHI, -1);
+ }
+
+ while (!Worklist.empty()) {
+ const Instruction *Pad;
+ int ParentState;
+ std::tie(Pad, ParentState) = Worklist.pop_back_val();
+
+ int PredState;
+ if (const CleanupEndPadInst *EndPad = dyn_cast<CleanupEndPadInst>(Pad)) {
+ FuncInfo.EHPadStateMap[EndPad] = ParentState;
+ // Queue the cleanuppad, in case it doesn't have a cleanupret.
+ Worklist.emplace_back(EndPad->getCleanupPad(), ParentState);
+ // Preds of the endpad should get the parent state.
+ PredState = ParentState;
+ } else if (const CleanupPadInst *Cleanup = dyn_cast<CleanupPadInst>(Pad)) {
+ // A cleanup can have multiple exits; don't re-process after the first.
+ if (FuncInfo.EHPadStateMap.count(Pad))
+ continue;
+ // CoreCLR personality uses arity to distinguish faults from finallies.
+ const BasicBlock *PadBlock = Cleanup->getParent();
+ ClrHandlerType HandlerType =
+ (Cleanup->getNumOperands() ? ClrHandlerType::Fault
+ : ClrHandlerType::Finally);
+ int NewState =
+ addClrEHHandler(FuncInfo, ParentState, HandlerType, 0, PadBlock);
+ FuncInfo.EHPadStateMap[Cleanup] = NewState;
+ // Propagate the new state to all preds of the cleanup
+ PredState = NewState;
+ } else if (const CatchEndPadInst *EndPad = dyn_cast<CatchEndPadInst>(Pad)) {
+ FuncInfo.EHPadStateMap[EndPad] = ParentState;
+ // Preds of the endpad should get the parent state.
+ PredState = ParentState;
+ } else if (const CatchPadInst *Catch = dyn_cast<CatchPadInst>(Pad)) {
+ const BasicBlock *Handler = Catch->getNormalDest();
+ uint32_t TypeToken = static_cast<uint32_t>(
+ cast<ConstantInt>(Catch->getArgOperand(0))->getZExtValue());
+ int NewState = addClrEHHandler(FuncInfo, ParentState,
+ ClrHandlerType::Catch, TypeToken, Handler);
+ FuncInfo.EHPadStateMap[Catch] = NewState;
+ // Preds of the catch get its state
+ PredState = NewState;
} else {
- auto *GV = cast<GlobalVariable>(CH->getSelector()->stripPointerCasts());
- // Selectors are always pointers to GlobalVariables with 'struct' type.
- // The struct has two fields, adjectives and a type descriptor.
- auto *CS = cast<ConstantStruct>(GV->getInitializer());
- HT.Adjectives =
- cast<ConstantInt>(CS->getAggregateElement(0U))->getZExtValue();
- HT.TypeDescriptor =
- cast<GlobalVariable>(CS->getAggregateElement(1)->stripPointerCasts());
+ llvm_unreachable("Unexpected EH pad");
+ }
+
+ // Queue all predecessors with the given state
+ for (const BasicBlock *Pred : predecessors(Pad->getParent())) {
+ if ((Pred = getEHPadFromPredecessor(Pred)))
+ Worklist.emplace_back(Pred->getFirstNonPHI(), PredState);
}
- HT.Handler = cast<Function>(CH->getHandlerBlockOrFunc());
- HT.CatchObjRecoverIdx = CH->getExceptionVarIndex();
- TBME.HandlerArray.push_back(HT);
}
- FuncInfo.TryBlockMap.push_back(TBME);
}
-static void print_name(const Value *V) {
-#ifndef NDEBUG
- if (!V) {
- DEBUG(dbgs() << "null");
+void WinEHPrepare::replaceTerminatePadWithCleanup(Function &F) {
+ if (Personality != EHPersonality::MSVC_CXX)
return;
+ for (BasicBlock &BB : F) {
+ Instruction *First = BB.getFirstNonPHI();
+ auto *TPI = dyn_cast<TerminatePadInst>(First);
+ if (!TPI)
+ continue;
+
+ if (TPI->getNumArgOperands() != 1)
+ report_fatal_error(
+ "Expected a unary terminatepad for MSVC C++ personalities!");
+
+ auto *TerminateFn = dyn_cast<Function>(TPI->getArgOperand(0));
+ if (!TerminateFn)
+ report_fatal_error("Function operand expected in terminatepad for MSVC "
+ "C++ personalities!");
+
+ // Insert the cleanuppad instruction.
+ auto *CPI = CleanupPadInst::Create(
+ BB.getContext(), {}, Twine("terminatepad.for.", BB.getName()), &BB);
+
+ // Insert the call to the terminate instruction.
+ auto *CallTerminate = CallInst::Create(TerminateFn, {}, &BB);
+ CallTerminate->setDoesNotThrow();
+ CallTerminate->setDoesNotReturn();
+ CallTerminate->setCallingConv(TerminateFn->getCallingConv());
+
+ // Insert a new terminator for the cleanuppad using the same successor as
+ // the terminatepad.
+ CleanupReturnInst::Create(CPI, TPI->getUnwindDest(), &BB);
+
+ // Let's remove the terminatepad now that we've inserted the new
+ // instructions.
+ TPI->eraseFromParent();
}
+}
- if (const auto *F = dyn_cast<Function>(V))
- DEBUG(dbgs() << F->getName());
- else
- DEBUG(V->dump());
-#endif
+static void
+colorFunclets(Function &F, SmallVectorImpl<BasicBlock *> &EntryBlocks,
+ std::map<BasicBlock *, std::set<BasicBlock *>> &BlockColors,
+ std::map<BasicBlock *, std::set<BasicBlock *>> &FuncletBlocks,
+ std::map<BasicBlock *, std::set<BasicBlock *>> &FuncletChildren) {
+ SmallVector<std::pair<BasicBlock *, BasicBlock *>, 16> Worklist;
+ BasicBlock *EntryBlock = &F.getEntryBlock();
+
+ // Build up the color map, which maps each block to its set of 'colors'.
+ // For any block B, the "colors" of B are the set of funclets F (possibly
+ // including a root "funclet" representing the main function), such that
+ // F will need to directly contain B or a copy of B (where the term "directly
+ // contain" is used to distinguish from being "transitively contained" in
+ // a nested funclet).
+ // Use a CFG walk driven by a worklist of (block, color) pairs. The "color"
+ // sets attached during this processing to a block which is the entry of some
+ // funclet F is actually the set of F's parents -- i.e. the union of colors
+ // of all predecessors of F's entry. For all other blocks, the color sets
+ // are as defined above. A post-pass fixes up the block color map to reflect
+ // the same sense of "color" for funclet entries as for other blocks.
+
+ Worklist.push_back({EntryBlock, EntryBlock});
+
+ while (!Worklist.empty()) {
+ BasicBlock *Visiting;
+ BasicBlock *Color;
+ std::tie(Visiting, Color) = Worklist.pop_back_val();
+ Instruction *VisitingHead = Visiting->getFirstNonPHI();
+ if (VisitingHead->isEHPad() && !isa<CatchEndPadInst>(VisitingHead) &&
+ !isa<CleanupEndPadInst>(VisitingHead)) {
+ // Mark this as a funclet head as a member of itself.
+ FuncletBlocks[Visiting].insert(Visiting);
+ // Queue exits with the parent color.
+ for (User *Exit : VisitingHead->users()) {
+ for (BasicBlock *Succ :
+ successors(cast<Instruction>(Exit)->getParent())) {
+ if (BlockColors[Succ].insert(Color).second) {
+ Worklist.push_back({Succ, Color});
+ }
+ }
+ }
+ // Handle CatchPad specially since its successors need different colors.
+ if (CatchPadInst *CatchPad = dyn_cast<CatchPadInst>(VisitingHead)) {
+ // Visit the normal successor with the color of the new EH pad, and
+ // visit the unwind successor with the color of the parent.
+ BasicBlock *NormalSucc = CatchPad->getNormalDest();
+ if (BlockColors[NormalSucc].insert(Visiting).second) {
+ Worklist.push_back({NormalSucc, Visiting});
+ }
+ BasicBlock *UnwindSucc = CatchPad->getUnwindDest();
+ if (BlockColors[UnwindSucc].insert(Color).second) {
+ Worklist.push_back({UnwindSucc, Color});
+ }
+ continue;
+ }
+ // Switch color to the current node, except for terminate pads which
+ // have no bodies and only unwind successors and so need their successors
+ // visited with the color of the parent.
+ if (!isa<TerminatePadInst>(VisitingHead))
+ Color = Visiting;
+ } else {
+ // Note that this is a member of the given color.
+ FuncletBlocks[Color].insert(Visiting);
+ }
+
+ TerminatorInst *Terminator = Visiting->getTerminator();
+ if (isa<CleanupReturnInst>(Terminator) ||
+ isa<CatchReturnInst>(Terminator) ||
+ isa<CleanupEndPadInst>(Terminator)) {
+ // These blocks' successors have already been queued with the parent
+ // color.
+ continue;
+ }
+ for (BasicBlock *Succ : successors(Visiting)) {
+ if (isa<CatchEndPadInst>(Succ->getFirstNonPHI())) {
+ // The catchendpad needs to be visited with the parent's color, not
+ // the current color. This will happen in the code above that visits
+ // any catchpad unwind successor with the parent color, so we can
+ // safely skip this successor here.
+ continue;
+ }
+ if (BlockColors[Succ].insert(Color).second) {
+ Worklist.push_back({Succ, Color});
+ }
+ }
+ }
+
+ // The processing above actually accumulated the parent set for this
+ // funclet into the color set for its entry; use the parent set to
+ // populate the children map, and reset the color set to include just
+ // the funclet itself (no instruction can target a funclet entry except on
+ // that transitions to the child funclet).
+ for (BasicBlock *FuncletEntry : EntryBlocks) {
+ std::set<BasicBlock *> &ColorMapItem = BlockColors[FuncletEntry];
+ for (BasicBlock *Parent : ColorMapItem)
+ FuncletChildren[Parent].insert(FuncletEntry);
+ ColorMapItem.clear();
+ ColorMapItem.insert(FuncletEntry);
+ }
}
-void WinEHNumbering::processCallSite(
- MutableArrayRef<std::unique_ptr<ActionHandler>> Actions,
- ImmutableCallSite CS) {
- DEBUG(dbgs() << "processCallSite (EH state = " << currentEHNumber()
- << ") for: ");
- print_name(CS ? CS.getCalledValue() : nullptr);
- DEBUG(dbgs() << '\n');
-
- DEBUG(dbgs() << "HandlerStack: \n");
- for (int I = 0, E = HandlerStack.size(); I < E; ++I) {
- DEBUG(dbgs() << " ");
- print_name(HandlerStack[I]->getHandlerBlockOrFunc());
- DEBUG(dbgs() << '\n');
- }
- DEBUG(dbgs() << "Actions: \n");
- for (int I = 0, E = Actions.size(); I < E; ++I) {
- DEBUG(dbgs() << " ");
- print_name(Actions[I]->getHandlerBlockOrFunc());
- DEBUG(dbgs() << '\n');
- }
- int FirstMismatch = 0;
- for (int E = std::min(HandlerStack.size(), Actions.size()); FirstMismatch < E;
- ++FirstMismatch) {
- if (HandlerStack[FirstMismatch]->getHandlerBlockOrFunc() !=
- Actions[FirstMismatch]->getHandlerBlockOrFunc())
- break;
+void WinEHPrepare::colorFunclets(Function &F,
+ SmallVectorImpl<BasicBlock *> &EntryBlocks) {
+ ::colorFunclets(F, EntryBlocks, BlockColors, FuncletBlocks, FuncletChildren);
+}
+
+void llvm::calculateCatchReturnSuccessorColors(const Function *Fn,
+ WinEHFuncInfo &FuncInfo) {
+ SmallVector<LandingPadInst *, 4> LPads;
+ SmallVector<ResumeInst *, 4> Resumes;
+ SmallVector<BasicBlock *, 4> EntryBlocks;
+ // colorFunclets needs the set of EntryBlocks, get them using
+ // findExceptionalConstructs.
+ bool ForExplicitEH = findExceptionalConstructs(const_cast<Function &>(*Fn),
+ LPads, Resumes, EntryBlocks);
+ if (!ForExplicitEH)
+ return;
+
+ std::map<BasicBlock *, std::set<BasicBlock *>> BlockColors;
+ std::map<BasicBlock *, std::set<BasicBlock *>> FuncletBlocks;
+ std::map<BasicBlock *, std::set<BasicBlock *>> FuncletChildren;
+ // Figure out which basic blocks belong to which funclets.
+ colorFunclets(const_cast<Function &>(*Fn), EntryBlocks, BlockColors,
+ FuncletBlocks, FuncletChildren);
+
+ // We need to find the catchret successors. To do this, we must first find
+ // all the catchpad funclets.
+ for (auto &Funclet : FuncletBlocks) {
+ // Figure out what kind of funclet we are looking at; We only care about
+ // catchpads.
+ BasicBlock *FuncletPadBB = Funclet.first;
+ Instruction *FirstNonPHI = FuncletPadBB->getFirstNonPHI();
+ auto *CatchPad = dyn_cast<CatchPadInst>(FirstNonPHI);
+ if (!CatchPad)
+ continue;
+
+ // The users of a catchpad are always catchrets.
+ for (User *Exit : CatchPad->users()) {
+ auto *CatchReturn = cast<CatchReturnInst>(Exit);
+ BasicBlock *CatchRetSuccessor = CatchReturn->getSuccessor();
+ std::set<BasicBlock *> &SuccessorColors = BlockColors[CatchRetSuccessor];
+ assert(SuccessorColors.size() == 1 && "Expected BB to be monochrome!");
+ BasicBlock *Color = *SuccessorColors.begin();
+ if (auto *CPI = dyn_cast<CatchPadInst>(Color->getFirstNonPHI()))
+ Color = CPI->getNormalDest();
+ // Record the catchret successor's funclet membership.
+ FuncInfo.CatchRetSuccessorColorMap[CatchReturn] = Color;
+ }
}
+}
- // Remove unmatched actions from the stack and process their EH states.
- popUnmatchedActions(FirstMismatch);
-
- DEBUG(dbgs() << "Pushing actions for CallSite: ");
- print_name(CS ? CS.getCalledValue() : nullptr);
- DEBUG(dbgs() << '\n');
-
- bool LastActionWasCatch = false;
- const LandingPadInst *LastRootLPad = nullptr;
- for (size_t I = FirstMismatch; I != Actions.size(); ++I) {
- // We can reuse eh states when pushing two catches for the same invoke.
- bool CurrActionIsCatch = isa<CatchHandler>(Actions[I].get());
- auto *Handler = cast<Function>(Actions[I]->getHandlerBlockOrFunc());
- // Various conditions can lead to a handler being popped from the
- // stack and re-pushed later. That shouldn't create a new state.
- // FIXME: Can code optimization lead to re-used handlers?
- if (FuncInfo.HandlerEnclosedState.count(Handler)) {
- // If we already assigned the state enclosed by this handler re-use it.
- Actions[I]->setEHState(FuncInfo.HandlerEnclosedState[Handler]);
+void WinEHPrepare::demotePHIsOnFunclets(Function &F) {
+ // Strip PHI nodes off of EH pads.
+ SmallVector<PHINode *, 16> PHINodes;
+ for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE;) {
+ BasicBlock *BB = FI++;
+ if (!BB->isEHPad())
continue;
+ for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) {
+ Instruction *I = BI++;
+ auto *PN = dyn_cast<PHINode>(I);
+ // Stop at the first non-PHI.
+ if (!PN)
+ break;
+
+ AllocaInst *SpillSlot = insertPHILoads(PN, F);
+ if (SpillSlot)
+ insertPHIStores(PN, SpillSlot);
+
+ PHINodes.push_back(PN);
}
- const LandingPadInst* RootLPad = FuncInfo.RootLPad[Handler];
- if (CurrActionIsCatch && LastActionWasCatch && RootLPad == LastRootLPad) {
- DEBUG(dbgs() << "setEHState for handler to " << currentEHNumber() << "\n");
- Actions[I]->setEHState(currentEHNumber());
- } else {
- DEBUG(dbgs() << "createUnwindMapEntry(" << currentEHNumber() << ", ");
- print_name(Actions[I]->getHandlerBlockOrFunc());
- DEBUG(dbgs() << ") with EH state " << NextState << "\n");
- createUnwindMapEntry(currentEHNumber(), Actions[I].get());
- DEBUG(dbgs() << "setEHState for handler to " << NextState << "\n");
- Actions[I]->setEHState(NextState);
- NextState++;
+ }
+
+ for (auto *PN : PHINodes) {
+ // There may be lingering uses on other EH PHIs being removed
+ PN->replaceAllUsesWith(UndefValue::get(PN->getType()));
+ PN->eraseFromParent();
+ }
+}
+
+void WinEHPrepare::demoteUsesBetweenFunclets(Function &F) {
+ // Turn all inter-funclet uses of a Value into loads and stores.
+ for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE;) {
+ BasicBlock *BB = FI++;
+ std::set<BasicBlock *> &ColorsForBB = BlockColors[BB];
+ for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) {
+ Instruction *I = BI++;
+ // Funclets are permitted to use static allocas.
+ if (auto *AI = dyn_cast<AllocaInst>(I))
+ if (AI->isStaticAlloca())
+ continue;
+
+ demoteNonlocalUses(I, ColorsForBB, F);
}
- HandlerStack.push_back(std::move(Actions[I]));
- LastActionWasCatch = CurrActionIsCatch;
- LastRootLPad = RootLPad;
}
+}
+
+void WinEHPrepare::demoteArgumentUses(Function &F) {
+ // Also demote function parameters used in funclets.
+ std::set<BasicBlock *> &ColorsForEntry = BlockColors[&F.getEntryBlock()];
+ for (Argument &Arg : F.args())
+ demoteNonlocalUses(&Arg, ColorsForEntry, F);
+}
- // This is used to defer numbering states for a handler until after the
- // last time it appears in an invoke action list.
- if (CS.isInvoke()) {
- for (int I = 0, E = HandlerStack.size(); I < E; ++I) {
- auto *Handler = cast<Function>(HandlerStack[I]->getHandlerBlockOrFunc());
- if (FuncInfo.LastInvoke[Handler] != cast<InvokeInst>(CS.getInstruction()))
+void WinEHPrepare::cloneCommonBlocks(
+ Function &F, SmallVectorImpl<BasicBlock *> &EntryBlocks) {
+ // We need to clone all blocks which belong to multiple funclets. Values are
+ // remapped throughout the funclet to propogate both the new instructions
+ // *and* the new basic blocks themselves.
+ for (BasicBlock *FuncletPadBB : EntryBlocks) {
+ std::set<BasicBlock *> &BlocksInFunclet = FuncletBlocks[FuncletPadBB];
+
+ std::map<BasicBlock *, BasicBlock *> Orig2Clone;
+ ValueToValueMapTy VMap;
+ for (BasicBlock *BB : BlocksInFunclet) {
+ std::set<BasicBlock *> &ColorsForBB = BlockColors[BB];
+ // We don't need to do anything if the block is monochromatic.
+ size_t NumColorsForBB = ColorsForBB.size();
+ if (NumColorsForBB == 1)
continue;
- FuncInfo.LastInvokeVisited[Handler] = true;
- DEBUG(dbgs() << "Last invoke of ");
- print_name(Handler);
- DEBUG(dbgs() << " has been visited.\n");
+
+ // Create a new basic block and copy instructions into it!
+ BasicBlock *CBB =
+ CloneBasicBlock(BB, VMap, Twine(".for.", FuncletPadBB->getName()));
+ // Insert the clone immediately after the original to ensure determinism
+ // and to keep the same relative ordering of any funclet's blocks.
+ CBB->insertInto(&F, BB->getNextNode());
+
+ // Add basic block mapping.
+ VMap[BB] = CBB;
+
+ // Record delta operations that we need to perform to our color mappings.
+ Orig2Clone[BB] = CBB;
}
- }
- DEBUG(dbgs() << "In EHState " << currentEHNumber() << " for CallSite: ");
- print_name(CS ? CS.getCalledValue() : nullptr);
- DEBUG(dbgs() << '\n');
-}
-
-void WinEHNumbering::popUnmatchedActions(int FirstMismatch) {
- // Don't recurse while we are looping over the handler stack. Instead, defer
- // the numbering of the catch handlers until we are done popping.
- SmallVector<CatchHandler *, 4> PoppedCatches;
- for (int I = HandlerStack.size() - 1; I >= FirstMismatch; --I) {
- std::unique_ptr<ActionHandler> Handler = HandlerStack.pop_back_val();
- if (isa<CatchHandler>(Handler.get()))
- PoppedCatches.push_back(cast<CatchHandler>(Handler.release()));
- }
-
- int TryHigh = NextState - 1;
- int LastTryLowIdx = 0;
- for (int I = 0, E = PoppedCatches.size(); I != E; ++I) {
- CatchHandler *CH = PoppedCatches[I];
- DEBUG(dbgs() << "Popped handler with state " << CH->getEHState() << "\n");
- if (I + 1 == E || CH->getEHState() != PoppedCatches[I + 1]->getEHState()) {
- int TryLow = CH->getEHState();
- auto Handlers =
- makeArrayRef(&PoppedCatches[LastTryLowIdx], I - LastTryLowIdx + 1);
- DEBUG(dbgs() << "createTryBlockMapEntry(" << TryLow << ", " << TryHigh);
- for (size_t J = 0; J < Handlers.size(); ++J) {
- DEBUG(dbgs() << ", ");
- print_name(Handlers[J]->getHandlerBlockOrFunc());
- }
- DEBUG(dbgs() << ")\n");
- createTryBlockMapEntry(TryLow, TryHigh, Handlers);
- LastTryLowIdx = I + 1;
+ // Update our color mappings to reflect that one block has lost a color and
+ // another has gained a color.
+ for (auto &BBMapping : Orig2Clone) {
+ BasicBlock *OldBlock = BBMapping.first;
+ BasicBlock *NewBlock = BBMapping.second;
+
+ BlocksInFunclet.insert(NewBlock);
+ BlockColors[NewBlock].insert(FuncletPadBB);
+
+ BlocksInFunclet.erase(OldBlock);
+ BlockColors[OldBlock].erase(FuncletPadBB);
}
- }
- for (CatchHandler *CH : PoppedCatches) {
- if (auto *F = dyn_cast<Function>(CH->getHandlerBlockOrFunc())) {
- if (FuncInfo.LastInvokeVisited[F]) {
- DEBUG(dbgs() << "Assigning base state " << NextState << " to ");
- print_name(F);
- DEBUG(dbgs() << '\n');
- FuncInfo.HandlerBaseState[F] = NextState;
- DEBUG(dbgs() << "createUnwindMapEntry(" << currentEHNumber()
- << ", null)\n");
- createUnwindMapEntry(currentEHNumber(), nullptr);
- ++NextState;
- calculateStateNumbers(*F);
+ // Loop over all of the instructions in the function, fixing up operand
+ // references as we go. This uses VMap to do all the hard work.
+ for (BasicBlock *BB : BlocksInFunclet)
+ // Loop over all instructions, fixing each one as we find it...
+ for (Instruction &I : *BB)
+ RemapInstruction(&I, VMap, RF_IgnoreMissingEntries);
+
+ // Check to see if SuccBB has PHI nodes. If so, we need to add entries to
+ // the PHI nodes for NewBB now.
+ for (auto &BBMapping : Orig2Clone) {
+ BasicBlock *OldBlock = BBMapping.first;
+ BasicBlock *NewBlock = BBMapping.second;
+ for (BasicBlock *SuccBB : successors(NewBlock)) {
+ for (Instruction &SuccI : *SuccBB) {
+ auto *SuccPN = dyn_cast<PHINode>(&SuccI);
+ if (!SuccPN)
+ break;
+
+ // Ok, we have a PHI node. Figure out what the incoming value was for
+ // the OldBlock.
+ int OldBlockIdx = SuccPN->getBasicBlockIndex(OldBlock);
+ if (OldBlockIdx == -1)
+ break;
+ Value *IV = SuccPN->getIncomingValue(OldBlockIdx);
+
+ // Remap the value if necessary.
+ if (auto *Inst = dyn_cast<Instruction>(IV)) {
+ ValueToValueMapTy::iterator I = VMap.find(Inst);
+ if (I != VMap.end())
+ IV = I->second;
+ }
+
+ SuccPN->addIncoming(IV, NewBlock);
+ }
}
- else {
- DEBUG(dbgs() << "Deferring handling of ");
- print_name(F);
- DEBUG(dbgs() << " until last invoke visited.\n");
+ }
+
+ for (ValueToValueMapTy::value_type VT : VMap) {
+ // If there were values defined in BB that are used outside the funclet,
+ // then we now have to update all uses of the value to use either the
+ // original value, the cloned value, or some PHI derived value. This can
+ // require arbitrary PHI insertion, of which we are prepared to do, clean
+ // these up now.
+ SmallVector<Use *, 16> UsesToRename;
+
+ auto *OldI = dyn_cast<Instruction>(const_cast<Value *>(VT.first));
+ if (!OldI)
+ continue;
+ auto *NewI = cast<Instruction>(VT.second);
+ // Scan all uses of this instruction to see if it is used outside of its
+ // funclet, and if so, record them in UsesToRename.
+ for (Use &U : OldI->uses()) {
+ Instruction *UserI = cast<Instruction>(U.getUser());
+ BasicBlock *UserBB = UserI->getParent();
+ std::set<BasicBlock *> &ColorsForUserBB = BlockColors[UserBB];
+ assert(!ColorsForUserBB.empty());
+ if (ColorsForUserBB.size() > 1 ||
+ *ColorsForUserBB.begin() != FuncletPadBB)
+ UsesToRename.push_back(&U);
}
+
+ // If there are no uses outside the block, we're done with this
+ // instruction.
+ if (UsesToRename.empty())
+ continue;
+
+ // We found a use of OldI outside of the funclet. Rename all uses of OldI
+ // that are outside its funclet to be uses of the appropriate PHI node
+ // etc.
+ SSAUpdater SSAUpdate;
+ SSAUpdate.Initialize(OldI->getType(), OldI->getName());
+ SSAUpdate.AddAvailableValue(OldI->getParent(), OldI);
+ SSAUpdate.AddAvailableValue(NewI->getParent(), NewI);
+
+ while (!UsesToRename.empty())
+ SSAUpdate.RewriteUseAfterInsertions(*UsesToRename.pop_back_val());
}
- delete CH;
}
}
-void WinEHNumbering::calculateStateNumbers(const Function &F) {
- auto I = VisitedHandlers.insert(&F);
- if (!I.second)
- return; // We've already visited this handler, don't renumber it.
+void WinEHPrepare::removeImplausibleTerminators(Function &F) {
+ // Remove implausible terminators and replace them with UnreachableInst.
+ for (auto &Funclet : FuncletBlocks) {
+ BasicBlock *FuncletPadBB = Funclet.first;
+ std::set<BasicBlock *> &BlocksInFunclet = Funclet.second;
+ Instruction *FirstNonPHI = FuncletPadBB->getFirstNonPHI();
+ auto *CatchPad = dyn_cast<CatchPadInst>(FirstNonPHI);
+ auto *CleanupPad = dyn_cast<CleanupPadInst>(FirstNonPHI);
+
+ for (BasicBlock *BB : BlocksInFunclet) {
+ TerminatorInst *TI = BB->getTerminator();
+ // CatchPadInst and CleanupPadInst can't transfer control to a ReturnInst.
+ bool IsUnreachableRet = isa<ReturnInst>(TI) && (CatchPad || CleanupPad);
+ // The token consumed by a CatchReturnInst must match the funclet token.
+ bool IsUnreachableCatchret = false;
+ if (auto *CRI = dyn_cast<CatchReturnInst>(TI))
+ IsUnreachableCatchret = CRI->getCatchPad() != CatchPad;
+ // The token consumed by a CleanupReturnInst must match the funclet token.
+ bool IsUnreachableCleanupret = false;
+ if (auto *CRI = dyn_cast<CleanupReturnInst>(TI))
+ IsUnreachableCleanupret = CRI->getCleanupPad() != CleanupPad;
+ // The token consumed by a CleanupEndPadInst must match the funclet token.
+ bool IsUnreachableCleanupendpad = false;
+ if (auto *CEPI = dyn_cast<CleanupEndPadInst>(TI))
+ IsUnreachableCleanupendpad = CEPI->getCleanupPad() != CleanupPad;
+ if (IsUnreachableRet || IsUnreachableCatchret ||
+ IsUnreachableCleanupret || IsUnreachableCleanupendpad) {
+ // Loop through all of our successors and make sure they know that one
+ // of their predecessors is going away.
+ for (BasicBlock *SuccBB : TI->successors())
+ SuccBB->removePredecessor(BB);
+
+ if (IsUnreachableCleanupendpad) {
+ // We can't simply replace a cleanupendpad with unreachable, because
+ // its predecessor edges are EH edges and unreachable is not an EH
+ // pad. Change all predecessors to the "unwind to caller" form.
+ for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
+ PI != PE;) {
+ BasicBlock *Pred = *PI++;
+ removeUnwindEdge(Pred);
+ }
+ }
- int OldBaseState = CurrentBaseState;
- if (FuncInfo.HandlerBaseState.count(&F)) {
- CurrentBaseState = FuncInfo.HandlerBaseState[&F];
+ new UnreachableInst(BB->getContext(), TI);
+ TI->eraseFromParent();
+ }
+ // FIXME: Check for invokes/cleanuprets/cleanupendpads which unwind to
+ // implausible catchendpads (i.e. catchendpad not in immediate parent
+ // funclet).
+ }
}
+}
- size_t SavedHandlerStackSize = HandlerStack.size();
+void WinEHPrepare::cleanupPreparedFunclets(Function &F) {
+ // Clean-up some of the mess we made by removing useles PHI nodes, trivial
+ // branches, etc.
+ for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE;) {
+ BasicBlock *BB = FI++;
+ SimplifyInstructionsInBlock(BB);
+ ConstantFoldTerminator(BB, /*DeleteDeadConditions=*/true);
+ MergeBlockIntoPredecessor(BB);
+ }
- DEBUG(dbgs() << "Calculating state numbers for: " << F.getName() << '\n');
- SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
- for (const BasicBlock &BB : F) {
- for (const Instruction &I : BB) {
- const auto *CI = dyn_cast<CallInst>(&I);
- if (!CI || CI->doesNotThrow())
- continue;
- processCallSite(None, CI);
+ // We might have some unreachable blocks after cleaning up some impossible
+ // control flow.
+ removeUnreachableBlocks(F);
+}
+
+void WinEHPrepare::verifyPreparedFunclets(Function &F) {
+ // Recolor the CFG to verify that all is well.
+ for (BasicBlock &BB : F) {
+ size_t NumColors = BlockColors[&BB].size();
+ assert(NumColors == 1 && "Expected monochromatic BB!");
+ if (NumColors == 0)
+ report_fatal_error("Uncolored BB!");
+ if (NumColors > 1)
+ report_fatal_error("Multicolor BB!");
+ if (!DisableDemotion) {
+ bool EHPadHasPHI = BB.isEHPad() && isa<PHINode>(BB.begin());
+ assert(!EHPadHasPHI && "EH Pad still has a PHI!");
+ if (EHPadHasPHI)
+ report_fatal_error("EH Pad still has a PHI!");
}
- const auto *II = dyn_cast<InvokeInst>(BB.getTerminator());
- if (!II)
- continue;
- const LandingPadInst *LPI = II->getLandingPadInst();
- auto *ActionsCall = dyn_cast<IntrinsicInst>(LPI->getNextNode());
- if (!ActionsCall)
- continue;
- parseEHActions(ActionsCall, ActionList);
- if (ActionList.empty())
- continue;
- processCallSite(ActionList, II);
- ActionList.clear();
- FuncInfo.LandingPadStateMap[LPI] = currentEHNumber();
- DEBUG(dbgs() << "Assigning state " << currentEHNumber()
- << " to landing pad at " << LPI->getParent()->getName()
- << '\n');
}
+}
- // Pop any actions that were pushed on the stack for this function.
- popUnmatchedActions(SavedHandlerStackSize);
+bool WinEHPrepare::prepareExplicitEH(
+ Function &F, SmallVectorImpl<BasicBlock *> &EntryBlocks) {
+ // Remove unreachable blocks. It is not valuable to assign them a color and
+ // their existence can trick us into thinking values are alive when they are
+ // not.
+ removeUnreachableBlocks(F);
- DEBUG(dbgs() << "Assigning max state " << NextState - 1
- << " to " << F.getName() << '\n');
- FuncInfo.CatchHandlerMaxState[&F] = NextState - 1;
+ replaceTerminatePadWithCleanup(F);
- CurrentBaseState = OldBaseState;
-}
+ // Determine which blocks are reachable from which funclet entries.
+ colorFunclets(F, EntryBlocks);
-// This function follows the same basic traversal as calculateStateNumbers
-// but it is necessary to identify the root landing pad associated
-// with each action before we start assigning state numbers.
-void WinEHNumbering::findActionRootLPads(const Function &F) {
- auto I = VisitedHandlers.insert(&F);
- if (!I.second)
- return; // We've already visited this handler, don't revisit it.
+ if (!DisableDemotion) {
+ demotePHIsOnFunclets(F);
- SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
- for (const BasicBlock &BB : F) {
- const auto *II = dyn_cast<InvokeInst>(BB.getTerminator());
- if (!II)
- continue;
- const LandingPadInst *LPI = II->getLandingPadInst();
- auto *ActionsCall = dyn_cast<IntrinsicInst>(LPI->getNextNode());
- if (!ActionsCall)
- continue;
+ demoteUsesBetweenFunclets(F);
+
+ demoteArgumentUses(F);
+ }
+
+ cloneCommonBlocks(F, EntryBlocks);
+
+ if (!DisableCleanups) {
+ removeImplausibleTerminators(F);
+
+ cleanupPreparedFunclets(F);
+ }
+
+ verifyPreparedFunclets(F);
+
+ BlockColors.clear();
+ FuncletBlocks.clear();
+ FuncletChildren.clear();
+
+ return true;
+}
- assert(ActionsCall->getIntrinsicID() == Intrinsic::eh_actions);
- parseEHActions(ActionsCall, ActionList);
- if (ActionList.empty())
+// TODO: Share loads when one use dominates another, or when a catchpad exit
+// dominates uses (needs dominators).
+AllocaInst *WinEHPrepare::insertPHILoads(PHINode *PN, Function &F) {
+ BasicBlock *PHIBlock = PN->getParent();
+ AllocaInst *SpillSlot = nullptr;
+
+ if (isa<CleanupPadInst>(PHIBlock->getFirstNonPHI())) {
+ // Insert a load in place of the PHI and replace all uses.
+ SpillSlot = new AllocaInst(PN->getType(), nullptr,
+ Twine(PN->getName(), ".wineh.spillslot"),
+ F.getEntryBlock().begin());
+ Value *V = new LoadInst(SpillSlot, Twine(PN->getName(), ".wineh.reload"),
+ PHIBlock->getFirstInsertionPt());
+ PN->replaceAllUsesWith(V);
+ return SpillSlot;
+ }
+
+ DenseMap<BasicBlock *, Value *> Loads;
+ for (Value::use_iterator UI = PN->use_begin(), UE = PN->use_end();
+ UI != UE;) {
+ Use &U = *UI++;
+ auto *UsingInst = cast<Instruction>(U.getUser());
+ BasicBlock *UsingBB = UsingInst->getParent();
+ if (UsingBB->isEHPad()) {
+ // Use is on an EH pad phi. Leave it alone; we'll insert loads and
+ // stores for it separately.
+ assert(isa<PHINode>(UsingInst));
continue;
- for (int I = 0, E = ActionList.size(); I < E; ++I) {
- if (auto *Handler
- = dyn_cast<Function>(ActionList[I]->getHandlerBlockOrFunc())) {
- FuncInfo.LastInvoke[Handler] = II;
- // Don't replace the root landing pad if we previously saw this
- // handler in a different function.
- if (FuncInfo.RootLPad.count(Handler) &&
- FuncInfo.RootLPad[Handler]->getParent()->getParent() != &F)
+ }
+ replaceUseWithLoad(PN, U, SpillSlot, Loads, F);
+ }
+ return SpillSlot;
+}
+
+// TODO: improve store placement. Inserting at def is probably good, but need
+// to be careful not to introduce interfering stores (needs liveness analysis).
+// TODO: identify related phi nodes that can share spill slots, and share them
+// (also needs liveness).
+void WinEHPrepare::insertPHIStores(PHINode *OriginalPHI,
+ AllocaInst *SpillSlot) {
+ // Use a worklist of (Block, Value) pairs -- the given Value needs to be
+ // stored to the spill slot by the end of the given Block.
+ SmallVector<std::pair<BasicBlock *, Value *>, 4> Worklist;
+
+ Worklist.push_back({OriginalPHI->getParent(), OriginalPHI});
+
+ while (!Worklist.empty()) {
+ BasicBlock *EHBlock;
+ Value *InVal;
+ std::tie(EHBlock, InVal) = Worklist.pop_back_val();
+
+ PHINode *PN = dyn_cast<PHINode>(InVal);
+ if (PN && PN->getParent() == EHBlock) {
+ // The value is defined by another PHI we need to remove, with no room to
+ // insert a store after the PHI, so each predecessor needs to store its
+ // incoming value.
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i < e; ++i) {
+ Value *PredVal = PN->getIncomingValue(i);
+
+ // Undef can safely be skipped.
+ if (isa<UndefValue>(PredVal))
continue;
- DEBUG(dbgs() << "Setting root lpad for ");
- print_name(Handler);
- DEBUG(dbgs() << " to " << LPI->getParent()->getName() << '\n');
- FuncInfo.RootLPad[Handler] = LPI;
+
+ insertPHIStore(PN->getIncomingBlock(i), PredVal, SpillSlot, Worklist);
+ }
+ } else {
+ // We need to store InVal, which dominates EHBlock, but can't put a store
+ // in EHBlock, so need to put stores in each predecessor.
+ for (BasicBlock *PredBlock : predecessors(EHBlock)) {
+ insertPHIStore(PredBlock, InVal, SpillSlot, Worklist);
}
}
- // Walk the actions again and look for nested handlers. This has to
- // happen after all of the actions have been processed in the current
- // function.
- for (int I = 0, E = ActionList.size(); I < E; ++I)
- if (auto *Handler
- = dyn_cast<Function>(ActionList[I]->getHandlerBlockOrFunc()))
- findActionRootLPads(*Handler);
- ActionList.clear();
}
}
-void llvm::calculateWinCXXEHStateNumbers(const Function *ParentFn,
- WinEHFuncInfo &FuncInfo) {
- // Return if it's already been done.
- if (!FuncInfo.LandingPadStateMap.empty())
+void WinEHPrepare::insertPHIStore(
+ BasicBlock *PredBlock, Value *PredVal, AllocaInst *SpillSlot,
+ SmallVectorImpl<std::pair<BasicBlock *, Value *>> &Worklist) {
+
+ if (PredBlock->isEHPad() &&
+ !isa<CleanupPadInst>(PredBlock->getFirstNonPHI())) {
+ // Pred is unsplittable, so we need to queue it on the worklist.
+ Worklist.push_back({PredBlock, PredVal});
return;
+ }
+
+ // Otherwise, insert the store at the end of the basic block.
+ new StoreInst(PredVal, SpillSlot, PredBlock->getTerminator());
+}
+
+// TODO: Share loads for same-funclet uses (requires dominators if funclets
+// aren't properly nested).
+void WinEHPrepare::demoteNonlocalUses(Value *V,
+ std::set<BasicBlock *> &ColorsForBB,
+ Function &F) {
+ // Tokens can only be used non-locally due to control flow involving
+ // unreachable edges. Don't try to demote the token usage, we'll simply
+ // delete the cloned user later.
+ if (isa<CatchPadInst>(V) || isa<CleanupPadInst>(V))
+ return;
+
+ DenseMap<BasicBlock *, Value *> Loads;
+ AllocaInst *SpillSlot = nullptr;
+ for (Value::use_iterator UI = V->use_begin(), UE = V->use_end(); UI != UE;) {
+ Use &U = *UI++;
+ auto *UsingInst = cast<Instruction>(U.getUser());
+ BasicBlock *UsingBB = UsingInst->getParent();
+
+ // Is the Use inside a block which is colored the same as the Def?
+ // If so, we don't need to escape the Def because we will clone
+ // ourselves our own private copy.
+ std::set<BasicBlock *> &ColorsForUsingBB = BlockColors[UsingBB];
+ if (ColorsForUsingBB == ColorsForBB)
+ continue;
+
+ replaceUseWithLoad(V, U, SpillSlot, Loads, F);
+ }
+ if (SpillSlot) {
+ // Insert stores of the computed value into the stack slot.
+ // We have to be careful if I is an invoke instruction,
+ // because we can't insert the store AFTER the terminator instruction.
+ BasicBlock::iterator InsertPt;
+ if (isa<Argument>(V)) {
+ InsertPt = F.getEntryBlock().getTerminator();
+ } else if (isa<TerminatorInst>(V)) {
+ auto *II = cast<InvokeInst>(V);
+ // We cannot demote invoke instructions to the stack if their normal
+ // edge is critical. Therefore, split the critical edge and create a
+ // basic block into which the store can be inserted.
+ if (!II->getNormalDest()->getSinglePredecessor()) {
+ unsigned SuccNum =
+ GetSuccessorNumber(II->getParent(), II->getNormalDest());
+ assert(isCriticalEdge(II, SuccNum) && "Expected a critical edge!");
+ BasicBlock *NewBlock = SplitCriticalEdge(II, SuccNum);
+ assert(NewBlock && "Unable to split critical edge.");
+ // Update the color mapping for the newly split edge.
+ std::set<BasicBlock *> &ColorsForUsingBB = BlockColors[II->getParent()];
+ BlockColors[NewBlock] = ColorsForUsingBB;
+ for (BasicBlock *FuncletPad : ColorsForUsingBB)
+ FuncletBlocks[FuncletPad].insert(NewBlock);
+ }
+ InsertPt = II->getNormalDest()->getFirstInsertionPt();
+ } else {
+ InsertPt = cast<Instruction>(V);
+ ++InsertPt;
+ // Don't insert before PHI nodes or EH pad instrs.
+ for (; isa<PHINode>(InsertPt) || InsertPt->isEHPad(); ++InsertPt)
+ ;
+ }
+ new StoreInst(V, SpillSlot, InsertPt);
+ }
+}
+
+void WinEHPrepare::replaceUseWithLoad(Value *V, Use &U, AllocaInst *&SpillSlot,
+ DenseMap<BasicBlock *, Value *> &Loads,
+ Function &F) {
+ // Lazilly create the spill slot.
+ if (!SpillSlot)
+ SpillSlot = new AllocaInst(V->getType(), nullptr,
+ Twine(V->getName(), ".wineh.spillslot"),
+ F.getEntryBlock().begin());
+
+ auto *UsingInst = cast<Instruction>(U.getUser());
+ if (auto *UsingPHI = dyn_cast<PHINode>(UsingInst)) {
+ // If this is a PHI node, we can't insert a load of the value before
+ // the use. Instead insert the load in the predecessor block
+ // corresponding to the incoming value.
+ //
+ // Note that if there are multiple edges from a basic block to this
+ // PHI node that we cannot have multiple loads. The problem is that
+ // the resulting PHI node will have multiple values (from each load)
+ // coming in from the same block, which is illegal SSA form.
+ // For this reason, we keep track of and reuse loads we insert.
+ BasicBlock *IncomingBlock = UsingPHI->getIncomingBlock(U);
+ if (auto *CatchRet =
+ dyn_cast<CatchReturnInst>(IncomingBlock->getTerminator())) {
+ // Putting a load above a catchret and use on the phi would still leave
+ // a cross-funclet def/use. We need to split the edge, change the
+ // catchret to target the new block, and put the load there.
+ BasicBlock *PHIBlock = UsingInst->getParent();
+ BasicBlock *NewBlock = SplitEdge(IncomingBlock, PHIBlock);
+ // SplitEdge gives us:
+ // IncomingBlock:
+ // ...
+ // br label %NewBlock
+ // NewBlock:
+ // catchret label %PHIBlock
+ // But we need:
+ // IncomingBlock:
+ // ...
+ // catchret label %NewBlock
+ // NewBlock:
+ // br label %PHIBlock
+ // So move the terminators to each others' blocks and swap their
+ // successors.
+ BranchInst *Goto = cast<BranchInst>(IncomingBlock->getTerminator());
+ Goto->removeFromParent();
+ CatchRet->removeFromParent();
+ IncomingBlock->getInstList().push_back(CatchRet);
+ NewBlock->getInstList().push_back(Goto);
+ Goto->setSuccessor(0, PHIBlock);
+ CatchRet->setSuccessor(NewBlock);
+ // Update the color mapping for the newly split edge.
+ std::set<BasicBlock *> &ColorsForPHIBlock = BlockColors[PHIBlock];
+ BlockColors[NewBlock] = ColorsForPHIBlock;
+ for (BasicBlock *FuncletPad : ColorsForPHIBlock)
+ FuncletBlocks[FuncletPad].insert(NewBlock);
+ // Treat the new block as incoming for load insertion.
+ IncomingBlock = NewBlock;
+ }
+ Value *&Load = Loads[IncomingBlock];
+ // Insert the load into the predecessor block
+ if (!Load)
+ Load = new LoadInst(SpillSlot, Twine(V->getName(), ".wineh.reload"),
+ /*Volatile=*/false, IncomingBlock->getTerminator());
+
+ U.set(Load);
+ } else {
+ // Reload right before the old use.
+ auto *Load = new LoadInst(SpillSlot, Twine(V->getName(), ".wineh.reload"),
+ /*Volatile=*/false, UsingInst);
+ U.set(Load);
+ }
+}
- WinEHNumbering Num(FuncInfo);
- Num.findActionRootLPads(*ParentFn);
- // The VisitedHandlers list is used by both findActionRootLPads and
- // calculateStateNumbers, but both functions need to visit all handlers.
- Num.VisitedHandlers.clear();
- Num.calculateStateNumbers(*ParentFn);
- // Pop everything on the handler stack.
- // It may be necessary to call this more than once because a handler can
- // be pushed on the stack as a result of clearing the stack.
- while (!Num.HandlerStack.empty())
- Num.processCallSite(None, ImmutableCallSite());
+void WinEHFuncInfo::addIPToStateRange(const BasicBlock *PadBB,
+ MCSymbol *InvokeBegin,
+ MCSymbol *InvokeEnd) {
+ assert(PadBB->isEHPad() && EHPadStateMap.count(PadBB->getFirstNonPHI()) &&
+ "should get EH pad BB with precomputed state");
+ InvokeToStateMap[InvokeBegin] =
+ std::make_pair(EHPadStateMap[PadBB->getFirstNonPHI()], InvokeEnd);
}