//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/Passes.h"
-#include "llvm/ADT/MapVector.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/SmallSet.h"
-#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/Dominators.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/IR/Module.h"
-#include "llvm/IR/PatternMatch.h"
#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Transforms/Utils/PromoteMemToReg.h"
-#include <memory>
+#include "llvm/Transforms/Utils/SSAUpdater.h"
using namespace llvm;
-using namespace llvm::PatternMatch;
#define DEBUG_TYPE "winehprepare"
-namespace {
-
-// This map is used to model frame variable usage during outlining, to
-// construct a structure type to hold the frame variables in a frame
-// allocation block, and to remap the frame variable allocas (including
-// spill locations as needed) to GEPs that get the variable from the
-// frame allocation structure.
-typedef MapVector<Value *, TinyPtrVector<AllocaInst *>> FrameVarInfoMap;
-
-// TinyPtrVector cannot hold nullptr, so we need our own sentinel that isn't
-// quite null.
-AllocaInst *getCatchObjectSentinel() {
- return static_cast<AllocaInst *>(nullptr) + 1;
-}
-
-typedef SmallSet<BasicBlock *, 4> VisitedBlockSet;
+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));
-class LandingPadActions;
-class LandingPadMap;
+static cl::opt<bool> DisableCleanups(
+ "disable-cleanups", cl::Hidden,
+ cl::desc("Do not remove implausible terminators or other similar cleanups"),
+ cl::init(false));
-typedef DenseMap<const BasicBlock *, CatchHandler *> CatchHandlerMapTy;
-typedef DenseMap<const BasicBlock *, CleanupHandler *> CleanupHandlerMapTy;
+namespace {
class WinEHPrepare : public FunctionPass {
public:
static char ID; // Pass identification, replacement for typeid.
- WinEHPrepare(const TargetMachine *TM = nullptr)
- : FunctionPass(ID) {
- if (TM)
- TheTriple = TM->getTargetTriple();
- }
+ WinEHPrepare(const TargetMachine *TM = nullptr) : FunctionPass(ID) {}
bool runOnFunction(Function &Fn) override;
}
private:
- bool prepareExceptionHandlers(Function &F,
- SmallVectorImpl<LandingPadInst *> &LPads);
- void identifyEHBlocks(Function &F, SmallVectorImpl<LandingPadInst *> &LPads);
- void promoteLandingPadValues(LandingPadInst *LPad);
- void demoteValuesLiveAcrossHandlers(Function &F,
- SmallVectorImpl<LandingPadInst *> &LPads);
- void findSEHEHReturnPoints(Function &F,
- SetVector<BasicBlock *> &EHReturnBlocks);
- void findCXXEHReturnPoints(Function &F,
- SetVector<BasicBlock *> &EHReturnBlocks);
- void getPossibleReturnTargets(Function *ParentF, Function *HandlerF,
- SetVector<BasicBlock*> &Targets);
- void completeNestedLandingPad(Function *ParentFn,
- LandingPadInst *OutlinedLPad,
- const LandingPadInst *OriginalLPad,
- FrameVarInfoMap &VarInfo);
- 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);
- void addStubInvokeToHandlerIfNeeded(Function *Handler);
-
- void mapLandingPadBlocks(LandingPadInst *LPad, LandingPadActions &Actions);
- CatchHandler *findCatchHandler(BasicBlock *BB, BasicBlock *&NextBB,
- VisitedBlockSet &VisitedBlocks);
- void findCleanupHandlers(LandingPadActions &Actions, BasicBlock *StartBB,
- BasicBlock *EndBB);
-
- void processSEHCatchHandler(CatchHandler *Handler, BasicBlock *StartBB);
void insertPHIStores(PHINode *OriginalPHI, AllocaInst *SpillSlot);
void
insertPHIStore(BasicBlock *PredBlock, Value *PredVal, AllocaInst *SpillSlot,
Function &F);
bool prepareExplicitEH(Function &F,
SmallVectorImpl<BasicBlock *> &EntryBlocks);
+ void replaceTerminatePadWithCleanup(Function &F);
void colorFunclets(Function &F, SmallVectorImpl<BasicBlock *> &EntryBlocks);
-
- Triple TheTriple;
+ 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);
// All fields are reset by runOnFunction.
- DominatorTree *DT = nullptr;
- const TargetLibraryInfo *LibInfo = nullptr;
EHPersonality Personality = EHPersonality::Unknown;
- CatchHandlerMapTy CatchHandlerMap;
- CleanupHandlerMapTy CleanupHandlerMap;
- DenseMap<const LandingPadInst *, LandingPadMap> LPadMaps;
- SmallPtrSet<BasicBlock *, 4> NormalBlocks;
- SmallPtrSet<BasicBlock *, 4> EHBlocks;
- SetVector<BasicBlock *> EHReturnBlocks;
-
- // This maps landing pad instructions found in outlined handlers to
- // the landing pad instruction in the parent function from which they
- // were cloned. The cloned/nested landing pad is used as the key
- // because the landing pad may be cloned into multiple handlers.
- // This map will be used to add the llvm.eh.actions call to the nested
- // landing pads after all handlers have been outlined.
- DenseMap<LandingPadInst *, const LandingPadInst *> NestedLPtoOriginalLP;
-
- // This maps blocks in the parent function which are destinations of
- // catch handlers to cloned blocks in (other) outlined handlers. This
- // handles the case where a nested landing pads has a catch handler that
- // returns to a handler function rather than the parent function.
- // The original block is used as the key here because there should only
- // ever be one handler function from which the cloned block is not pruned.
- // The original block will be pruned from the parent function after all
- // handlers have been outlined. This map will be used to adjust the
- // return instructions of handlers which return to the block that was
- // outlined into a handler. This is done after all handlers have been
- // outlined but before the outlined code is pruned from the parent function.
- DenseMap<const BasicBlock *, BasicBlock *> LPadTargetBlocks;
-
- // 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 {
-public:
- WinEHFrameVariableMaterializer(Function *OutlinedFn, Value *ParentFP,
- FrameVarInfoMap &FrameVarInfo);
- ~WinEHFrameVariableMaterializer() override {}
-
- Value *materializeValueFor(Value *V) override;
-
- void escapeCatchObject(Value *V);
-
-private:
- FrameVarInfoMap &FrameVarInfo;
- IRBuilder<> Builder;
-};
-
-class LandingPadMap {
-public:
- LandingPadMap() : OriginLPad(nullptr) {}
- void mapLandingPad(const LandingPadInst *LPad);
-
- bool isInitialized() { return OriginLPad != nullptr; }
-
- bool isOriginLandingPadBlock(const BasicBlock *BB) const;
- bool isLandingPadSpecificInst(const Instruction *Inst) const;
-
- void remapEHValues(ValueToValueMapTy &VMap, Value *EHPtrValue,
- Value *SelectorValue) const;
-
-private:
- const LandingPadInst *OriginLPad;
- // We will normally only see one of each of these instructions, but
- // if more than one occurs for some reason we can handle that.
- TinyPtrVector<const ExtractValueInst *> ExtractedEHPtrs;
- TinyPtrVector<const ExtractValueInst *> ExtractedSelectors;
-};
-
-class WinEHCloningDirectorBase : public CloningDirector {
-public:
- WinEHCloningDirectorBase(Function *HandlerFn, Value *ParentFP,
- FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap)
- : Materializer(HandlerFn, ParentFP, VarInfo),
- SelectorIDType(Type::getInt32Ty(HandlerFn->getContext())),
- Int8PtrType(Type::getInt8PtrTy(HandlerFn->getContext())),
- LPadMap(LPadMap), ParentFP(ParentFP) {}
-
- CloningAction handleInstruction(ValueToValueMapTy &VMap,
- const Instruction *Inst,
- BasicBlock *NewBB) override;
-
- virtual CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
- const Instruction *Inst,
- BasicBlock *NewBB) = 0;
- virtual CloningAction handleEndCatch(ValueToValueMapTy &VMap,
- const Instruction *Inst,
- BasicBlock *NewBB) = 0;
- virtual CloningAction handleTypeIdFor(ValueToValueMapTy &VMap,
- const Instruction *Inst,
- BasicBlock *NewBB) = 0;
- virtual CloningAction handleIndirectBr(ValueToValueMapTy &VMap,
- const IndirectBrInst *IBr,
- BasicBlock *NewBB) = 0;
- virtual CloningAction handleInvoke(ValueToValueMapTy &VMap,
- const InvokeInst *Invoke,
- BasicBlock *NewBB) = 0;
- virtual CloningAction handleResume(ValueToValueMapTy &VMap,
- const ResumeInst *Resume,
- BasicBlock *NewBB) = 0;
- virtual CloningAction handleCompare(ValueToValueMapTy &VMap,
- const CmpInst *Compare,
- BasicBlock *NewBB) = 0;
- virtual CloningAction handleLandingPad(ValueToValueMapTy &VMap,
- const LandingPadInst *LPad,
- BasicBlock *NewBB) = 0;
-
- ValueMaterializer *getValueMaterializer() override { return &Materializer; }
-
-protected:
- WinEHFrameVariableMaterializer Materializer;
- Type *SelectorIDType;
- Type *Int8PtrType;
- LandingPadMap &LPadMap;
-
- /// The value representing the parent frame pointer.
- Value *ParentFP;
-};
-
-class WinEHCatchDirector : public WinEHCloningDirectorBase {
-public:
- WinEHCatchDirector(
- Function *CatchFn, Value *ParentFP, Value *Selector,
- FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap,
- DenseMap<LandingPadInst *, const LandingPadInst *> &NestedLPads,
- DominatorTree *DT, SmallPtrSetImpl<BasicBlock *> &EHBlocks)
- : WinEHCloningDirectorBase(CatchFn, ParentFP, VarInfo, LPadMap),
- CurrentSelector(Selector->stripPointerCasts()),
- ExceptionObjectVar(nullptr), NestedLPtoOriginalLP(NestedLPads),
- DT(DT), EHBlocks(EHBlocks) {}
-
- CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
- const Instruction *Inst,
- BasicBlock *NewBB) override;
- CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst,
- BasicBlock *NewBB) override;
- CloningAction handleTypeIdFor(ValueToValueMapTy &VMap,
- const Instruction *Inst,
- BasicBlock *NewBB) override;
- CloningAction handleIndirectBr(ValueToValueMapTy &VMap,
- const IndirectBrInst *IBr,
- BasicBlock *NewBB) override;
- CloningAction handleInvoke(ValueToValueMapTy &VMap, const InvokeInst *Invoke,
- BasicBlock *NewBB) override;
- CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume,
- BasicBlock *NewBB) override;
- CloningAction handleCompare(ValueToValueMapTy &VMap, const CmpInst *Compare,
- BasicBlock *NewBB) override;
- CloningAction handleLandingPad(ValueToValueMapTy &VMap,
- const LandingPadInst *LPad,
- BasicBlock *NewBB) override;
-
- Value *getExceptionVar() { return ExceptionObjectVar; }
- TinyPtrVector<BasicBlock *> &getReturnTargets() { return ReturnTargets; }
-
-private:
- Value *CurrentSelector;
-
- Value *ExceptionObjectVar;
- TinyPtrVector<BasicBlock *> ReturnTargets;
-
- // This will be a reference to the field of the same name in the WinEHPrepare
- // object which instantiates this WinEHCatchDirector object.
- DenseMap<LandingPadInst *, const LandingPadInst *> &NestedLPtoOriginalLP;
- DominatorTree *DT;
- SmallPtrSetImpl<BasicBlock *> &EHBlocks;
-};
-
-class WinEHCleanupDirector : public WinEHCloningDirectorBase {
-public:
- WinEHCleanupDirector(Function *CleanupFn, Value *ParentFP,
- FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap)
- : WinEHCloningDirectorBase(CleanupFn, ParentFP, VarInfo,
- LPadMap) {}
-
- CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
- const Instruction *Inst,
- BasicBlock *NewBB) override;
- CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst,
- BasicBlock *NewBB) override;
- CloningAction handleTypeIdFor(ValueToValueMapTy &VMap,
- const Instruction *Inst,
- BasicBlock *NewBB) override;
- CloningAction handleIndirectBr(ValueToValueMapTy &VMap,
- const IndirectBrInst *IBr,
- BasicBlock *NewBB) override;
- CloningAction handleInvoke(ValueToValueMapTy &VMap, const InvokeInst *Invoke,
- BasicBlock *NewBB) override;
- CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume,
- BasicBlock *NewBB) override;
- CloningAction handleCompare(ValueToValueMapTy &VMap, const CmpInst *Compare,
- BasicBlock *NewBB) override;
- CloningAction handleLandingPad(ValueToValueMapTy &VMap,
- const LandingPadInst *LPad,
- BasicBlock *NewBB) override;
-};
-
-class LandingPadActions {
-public:
- LandingPadActions() : HasCleanupHandlers(false) {}
-
- void insertCatchHandler(CatchHandler *Action) { Actions.push_back(Action); }
- void insertCleanupHandler(CleanupHandler *Action) {
- Actions.push_back(Action);
- HasCleanupHandlers = true;
- }
-
- bool includesCleanup() const { return HasCleanupHandlers; }
-
- SmallVectorImpl<ActionHandler *> &actions() { return Actions; }
- SmallVectorImpl<ActionHandler *>::iterator begin() { return Actions.begin(); }
- SmallVectorImpl<ActionHandler *>::iterator end() { return Actions.end(); }
-
-private:
- // Note that this class does not own the ActionHandler objects in this vector.
- // The ActionHandlers are owned by the CatchHandlerMap and CleanupHandlerMap
- // in the WinEHPrepare class.
- SmallVector<ActionHandler *, 4> Actions;
- bool HasCleanupHandlers;
-};
-
} // end anonymous namespace
char WinEHPrepare::ID = 0;
return new WinEHPrepare(TM);
}
-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))
- return false;
-
- SmallVector<LandingPadInst *, 4> LPads;
- SmallVector<ResumeInst *, 4> Resumes;
- SmallVector<BasicBlock *, 4> EntryBlocks;
- bool ForExplicitEH = false;
+static void findFuncletEntryPoints(Function &Fn,
+ SmallVectorImpl<BasicBlock *> &EntryBlocks) {
+ EntryBlocks.push_back(&Fn.getEntryBlock());
for (BasicBlock &BB : Fn) {
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);
- }
-
- if (ForExplicitEH)
- return prepareExplicitEH(Fn, EntryBlocks);
-
- // No need to prepare functions that lack landing pads.
- if (LPads.empty())
- return false;
-
- DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
- LibInfo = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
-
- // If there were any landing pads, prepareExceptionHandlers will make changes.
- prepareExceptionHandlers(Fn, LPads);
- return true;
-}
-
-bool WinEHPrepare::doFinalization(Module &M) { return false; }
-
-void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequired<DominatorTreeWrapperPass>();
- AU.addRequired<TargetLibraryInfoWrapperPass>();
-}
-
-static bool isSelectorDispatch(BasicBlock *BB, BasicBlock *&CatchHandler,
- Constant *&Selector, BasicBlock *&NextBB);
-
-// Finds blocks reachable from the starting set Worklist. Does not follow unwind
-// edges or blocks listed in StopPoints.
-static void findReachableBlocks(SmallPtrSetImpl<BasicBlock *> &ReachableBBs,
- SetVector<BasicBlock *> &Worklist,
- const SetVector<BasicBlock *> *StopPoints) {
- while (!Worklist.empty()) {
- BasicBlock *BB = Worklist.pop_back_val();
-
- // Don't cross blocks that we should stop at.
- if (StopPoints && StopPoints->count(BB))
- continue;
-
- if (!ReachableBBs.insert(BB).second)
- continue; // Already visited.
-
- // Don't follow unwind edges of invokes.
- if (auto *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
- Worklist.insert(II->getNormalDest());
+ if (!First->isEHPad())
continue;
- }
-
- // Otherwise, follow all successors.
- Worklist.insert(succ_begin(BB), succ_end(BB));
- }
-}
-
-// Attempt to find an instruction where a block can be split before
-// a call to llvm.eh.begincatch and its operands. If the block
-// begins with the begincatch call or one of its adjacent operands
-// the block will not be split.
-static Instruction *findBeginCatchSplitPoint(BasicBlock *BB,
- IntrinsicInst *II) {
- // If the begincatch call is already the first instruction in the block,
- // don't split.
- Instruction *FirstNonPHI = BB->getFirstNonPHI();
- if (II == FirstNonPHI)
- return nullptr;
-
- // If either operand is in the same basic block as the instruction and
- // isn't used by another instruction before the begincatch call, include it
- // in the split block.
- auto *Op0 = dyn_cast<Instruction>(II->getOperand(0));
- auto *Op1 = dyn_cast<Instruction>(II->getOperand(1));
-
- Instruction *I = II->getPrevNode();
- Instruction *LastI = II;
-
- while (I == Op0 || I == Op1) {
- // If the block begins with one of the operands and there are no other
- // instructions between the operand and the begincatch call, don't split.
- if (I == FirstNonPHI)
- return nullptr;
-
- LastI = I;
- I = I->getPrevNode();
- }
-
- // If there is at least one instruction in the block before the begincatch
- // call and its operands, split the block at either the begincatch or
- // its operand.
- return LastI;
-}
-
-/// Find all points where exceptional control rejoins normal control flow via
-/// llvm.eh.endcatch. Add them to the normal bb reachability worklist.
-void WinEHPrepare::findCXXEHReturnPoints(
- Function &F, SetVector<BasicBlock *> &EHReturnBlocks) {
- for (auto BBI = F.begin(), BBE = F.end(); BBI != BBE; ++BBI) {
- BasicBlock *BB = BBI;
- for (Instruction &I : *BB) {
- if (match(&I, m_Intrinsic<Intrinsic::eh_begincatch>())) {
- Instruction *SplitPt =
- findBeginCatchSplitPoint(BB, cast<IntrinsicInst>(&I));
- if (SplitPt) {
- // Split the block before the llvm.eh.begincatch call to allow
- // cleanup and catch code to be distinguished later.
- // Do not update BBI because we still need to process the
- // portion of the block that we are splitting off.
- SplitBlock(BB, SplitPt, DT);
- break;
- }
- }
- if (match(&I, m_Intrinsic<Intrinsic::eh_endcatch>())) {
- // Split the block after the call to llvm.eh.endcatch if there is
- // anything other than an unconditional branch, or if the successor
- // starts with a phi.
- auto *Br = dyn_cast<BranchInst>(I.getNextNode());
- if (!Br || !Br->isUnconditional() ||
- isa<PHINode>(Br->getSuccessor(0)->begin())) {
- DEBUG(dbgs() << "splitting block " << BB->getName()
- << " with llvm.eh.endcatch\n");
- BBI = SplitBlock(BB, I.getNextNode(), DT);
- }
- // The next BB is normal control flow.
- EHReturnBlocks.insert(BB->getTerminator()->getSuccessor(0));
- break;
- }
- }
- }
-}
-
-static bool isCatchAllLandingPad(const BasicBlock *BB) {
- const LandingPadInst *LP = BB->getLandingPadInst();
- if (!LP)
- return false;
- unsigned N = LP->getNumClauses();
- return (N > 0 && LP->isCatch(N - 1) &&
- isa<ConstantPointerNull>(LP->getClause(N - 1)));
-}
-
-/// Find all points where exceptions control rejoins normal control flow via
-/// selector dispatch.
-void WinEHPrepare::findSEHEHReturnPoints(
- Function &F, SetVector<BasicBlock *> &EHReturnBlocks) {
- for (auto BBI = F.begin(), BBE = F.end(); BBI != BBE; ++BBI) {
- BasicBlock *BB = BBI;
- // If the landingpad is a catch-all, treat the whole lpad as if it is
- // reachable from normal control flow.
- // FIXME: This is imprecise. We need a better way of identifying where a
- // catch-all starts and cleanups stop. As far as LLVM is concerned, there
- // is no difference.
- if (isCatchAllLandingPad(BB)) {
- EHReturnBlocks.insert(BB);
- continue;
- }
-
- BasicBlock *CatchHandler;
- BasicBlock *NextBB;
- Constant *Selector;
- if (isSelectorDispatch(BB, CatchHandler, Selector, NextBB)) {
- // 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(
- BB, std::find(succ_begin(BB), succ_end(BB), CatchHandler));
- }
- EHReturnBlocks.insert(CatchHandler);
- }
- }
-}
-
-void WinEHPrepare::identifyEHBlocks(Function &F,
- SmallVectorImpl<LandingPadInst *> &LPads) {
- DEBUG(dbgs() << "Demoting values live across exception handlers in function "
- << F.getName() << '\n');
-
- // Build a set of all non-exceptional blocks and exceptional blocks.
- // - Non-exceptional blocks are blocks reachable from the entry block while
- // not following invoke unwind edges.
- // - Exceptional blocks are blocks reachable from landingpads. Analysis does
- // not follow llvm.eh.endcatch blocks, which mark a transition from
- // exceptional to normal control.
-
- if (Personality == EHPersonality::MSVC_CXX)
- findCXXEHReturnPoints(F, EHReturnBlocks);
- else
- findSEHEHReturnPoints(F, EHReturnBlocks);
-
- DEBUG({
- dbgs() << "identified the following blocks as EH return points:\n";
- for (BasicBlock *BB : EHReturnBlocks)
- dbgs() << " " << BB->getName() << '\n';
- });
-
-// Join points should not have phis at this point, unless they are a
-// landingpad, in which case we will demote their phis later.
-#ifndef NDEBUG
- for (BasicBlock *BB : EHReturnBlocks)
- assert((BB->isLandingPad() || !isa<PHINode>(BB->begin())) &&
- "non-lpad EH return block has phi");
-#endif
-
- // Normal blocks are the blocks reachable from the entry block and all EH
- // return points.
- SetVector<BasicBlock *> Worklist;
- Worklist = EHReturnBlocks;
- Worklist.insert(&F.getEntryBlock());
- findReachableBlocks(NormalBlocks, Worklist, nullptr);
- DEBUG({
- dbgs() << "marked the following blocks as normal:\n";
- for (BasicBlock *BB : NormalBlocks)
- dbgs() << " " << BB->getName() << '\n';
- });
-
- // Exceptional blocks are the blocks reachable from landingpads that don't
- // cross EH return points.
- Worklist.clear();
- for (auto *LPI : LPads)
- Worklist.insert(LPI->getParent());
- findReachableBlocks(EHBlocks, Worklist, &EHReturnBlocks);
- DEBUG({
- dbgs() << "marked the following blocks as exceptional:\n";
- for (BasicBlock *BB : EHBlocks)
- dbgs() << " " << BB->getName() << '\n';
- });
-
-}
-
-/// Ensure that all values live into and out of exception handlers are stored
-/// in memory.
-/// FIXME: This falls down when values are defined in one handler and live into
-/// another handler. For example, a cleanup defines a value used only by a
-/// catch handler.
-void WinEHPrepare::demoteValuesLiveAcrossHandlers(
- Function &F, SmallVectorImpl<LandingPadInst *> &LPads) {
- DEBUG(dbgs() << "Demoting values live across exception handlers in function "
- << F.getName() << '\n');
-
- // 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) {
- bool IsNormalBB = NormalBlocks.count(&BB);
- bool IsEHBB = EHBlocks.count(&BB);
- if (!IsNormalBB && !IsEHBB)
- continue; // Blocks that are neither normal nor EH are unreachable.
- for (Instruction &I : BB) {
- for (Value *Op : I.operands()) {
- // Don't demote static allocas, constants, and labels.
- if (isa<Constant>(Op) || isa<BasicBlock>(Op) || isa<InlineAsm>(Op))
- continue;
- auto *AI = dyn_cast<AllocaInst>(Op);
- if (AI && AI->isStaticAlloca())
- continue;
-
- if (auto *Arg = dyn_cast<Argument>(Op)) {
- if (IsEHBB) {
- DEBUG(dbgs() << "Demoting argument " << *Arg
- << " used by EH instr: " << I << "\n");
- ArgsToDemote.insert(Arg);
- }
- 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.
- if (OpBB == &BB)
- continue;
- bool IsOpNormalBB = NormalBlocks.count(OpBB);
- bool IsOpEHBB = EHBlocks.count(OpBB);
- if (IsNormalBB != IsOpNormalBB || IsEHBB != IsOpEHBB) {
- DEBUG({
- dbgs() << "Demoting instruction live in-out from EH:\n";
- dbgs() << "Instr: " << *OpI << '\n';
- dbgs() << "User: " << I << '\n';
- });
- InstrsToDemote.insert(OpI);
- }
- }
- }
+ assert(!isa<LandingPadInst>(First) &&
+ "landingpad cannot be used with funclet EH personality");
+ // Find EH pad blocks that represent funclet start points.
+ if (!isa<CatchEndPadInst>(First) && !isa<CleanupEndPadInst>(First))
+ EntryBlocks.push_back(&BB);
}
-
- // Demote values live into and out of handlers.
- // FIXME: This demotion is inefficient. We should insert spills at the point
- // of definition, insert one reload in each handler that uses the value, and
- // insert reloads in the BB used to rejoin normal control flow.
- Instruction *AllocaInsertPt = F.getEntryBlock().getFirstInsertionPt();
- for (Instruction *I : InstrsToDemote)
- DemoteRegToStack(*I, false, AllocaInsertPt);
-
- // Demote arguments separately, and only for uses in EH blocks.
- for (Argument *Arg : ArgsToDemote) {
- auto *Slot = new AllocaInst(Arg->getType(), nullptr,
- Arg->getName() + ".reg2mem", AllocaInsertPt);
- SmallVector<User *, 4> Users(Arg->user_begin(), Arg->user_end());
- for (User *U : Users) {
- auto *I = dyn_cast<Instruction>(U);
- if (I && EHBlocks.count(I->getParent())) {
- auto *Reload = new LoadInst(Slot, Arg->getName() + ".reload", false, I);
- U->replaceUsesOfWith(Arg, Reload);
- }
- }
- new StoreInst(Arg, Slot, AllocaInsertPt);
- }
-
- // Demote landingpad phis, as the landingpad will be removed from the machine
- // CFG.
- for (LandingPadInst *LPI : LPads) {
- BasicBlock *BB = LPI->getParent();
- while (auto *Phi = dyn_cast<PHINode>(BB->begin()))
- DemotePHIToStack(Phi, AllocaInsertPt);
- }
-
- DEBUG(dbgs() << "Demoted " << InstrsToDemote.size() << " instructions and "
- << ArgsToDemote.size() << " arguments for WinEHPrepare\n\n");
}
-bool WinEHPrepare::prepareExceptionHandlers(
- Function &F, SmallVectorImpl<LandingPadInst *> &LPads) {
- // Don't run on functions that are already prepared.
- for (LandingPadInst *LPad : LPads) {
- BasicBlock *LPadBB = LPad->getParent();
- for (Instruction &Inst : *LPadBB)
- if (match(&Inst, m_Intrinsic<Intrinsic::eh_actions>()))
- return false;
- }
-
- identifyEHBlocks(F, LPads);
- demoteValuesLiveAcrossHandlers(F, LPads);
-
- // These containers are used to re-map frame variables that are used in
- // outlined catch and cleanup handlers. They will be populated as the
- // handlers are outlined.
- FrameVarInfoMap FrameVarInfo;
-
- bool HandlersOutlined = false;
-
- Module *M = F.getParent();
- LLVMContext &Context = M->getContext();
-
- // Create a new function to receive the handler contents.
- PointerType *Int8PtrType = Type::getInt8PtrTy(Context);
- Type *Int32Type = Type::getInt32Ty(Context);
- Function *ActionIntrin = Intrinsic::getDeclaration(M, Intrinsic::eh_actions);
-
- if (isAsynchronousEHPersonality(Personality)) {
- // FIXME: Switch the ehptr type to i32 and then switch this.
- SEHExceptionCodeSlot =
- new AllocaInst(Int8PtrType, nullptr, "seh_exception_code",
- F.getEntryBlock().getFirstInsertionPt());
- }
-
- // In order to handle the case where one outlined catch handler returns
- // to a block within another outlined catch handler that would otherwise
- // be unreachable, we need to outline the nested landing pad before we
- // outline the landing pad which encloses it.
- if (!isAsynchronousEHPersonality(Personality))
- std::sort(LPads.begin(), LPads.end(),
- [this](LandingPadInst *const &L, LandingPadInst *const &R) {
- return DT->properlyDominates(R->getParent(), L->getParent());
- });
-
- // This container stores the llvm.eh.recover and IndirectBr instructions
- // that make up the body of each landing pad after it has been outlined.
- // We need to defer the population of the target list for the indirectbr
- // until all landing pads have been outlined so that we can handle the
- // case of blocks in the target that are reached only from nested
- // landing pads.
- SmallVector<std::pair<CallInst*, IndirectBrInst *>, 4> LPadImpls;
-
- for (LandingPadInst *LPad : LPads) {
- // Look for evidence that this landingpad has already been processed.
- bool LPadHasActionList = false;
- BasicBlock *LPadBB = LPad->getParent();
- for (Instruction &Inst : *LPadBB) {
- if (match(&Inst, m_Intrinsic<Intrinsic::eh_actions>())) {
- LPadHasActionList = true;
- break;
- }
- }
-
- // If we've already outlined the handlers for this landingpad,
- // there's nothing more to do here.
- if (LPadHasActionList)
- continue;
-
- // If either of the values in the aggregate returned by the landing pad is
- // extracted and stored to memory, promote the stored value to a register.
- promoteLandingPadValues(LPad);
-
- LandingPadActions Actions;
- mapLandingPadBlocks(LPad, Actions);
-
- HandlersOutlined |= !Actions.actions().empty();
- for (ActionHandler *Action : Actions) {
- if (Action->hasBeenProcessed())
- continue;
- BasicBlock *StartBB = Action->getStartBlock();
-
- // SEH doesn't do any outlining for catches. Instead, pass the handler
- // basic block addr to llvm.eh.actions and list the block as a return
- // target.
- if (isAsynchronousEHPersonality(Personality)) {
- if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
- processSEHCatchHandler(CatchAction, StartBB);
- continue;
- }
- }
-
- outlineHandler(Action, &F, LPad, StartBB, FrameVarInfo);
- }
-
- // Split the block after the landingpad instruction so that it is just a
- // call to llvm.eh.actions followed by indirectbr.
- assert(!isa<PHINode>(LPadBB->begin()) && "lpad phi not removed");
- SplitBlock(LPadBB, LPad->getNextNode(), DT);
- // Erase the branch inserted by the split so we can insert indirectbr.
- LPadBB->getTerminator()->eraseFromParent();
-
- // Replace all extracted values with undef and ultimately replace the
- // landingpad with undef.
- SmallVector<Instruction *, 4> SEHCodeUses;
- SmallVector<Instruction *, 4> EHUndefs;
- for (User *U : LPad->users()) {
- auto *E = dyn_cast<ExtractValueInst>(U);
- if (!E)
- continue;
- assert(E->getNumIndices() == 1 &&
- "Unexpected operation: extracting both landing pad values");
- unsigned Idx = *E->idx_begin();
- assert((Idx == 0 || Idx == 1) && "unexpected index");
- if (Idx == 0 && isAsynchronousEHPersonality(Personality))
- SEHCodeUses.push_back(E);
- else
- EHUndefs.push_back(E);
- }
- for (Instruction *E : EHUndefs) {
- E->replaceAllUsesWith(UndefValue::get(E->getType()));
- E->eraseFromParent();
- }
- LPad->replaceAllUsesWith(UndefValue::get(LPad->getType()));
-
- // Rewrite uses of the exception pointer to loads of an alloca.
- while (!SEHCodeUses.empty()) {
- Instruction *E = SEHCodeUses.pop_back_val();
- SmallVector<Use *, 4> Uses;
- for (Use &U : E->uses())
- Uses.push_back(&U);
- for (Use *U : Uses) {
- auto *I = cast<Instruction>(U->getUser());
- if (isa<ResumeInst>(I))
- continue;
- if (auto *Phi = dyn_cast<PHINode>(I))
- SEHCodeUses.push_back(Phi);
- else
- U->set(new LoadInst(SEHExceptionCodeSlot, "sehcode", false, I));
- }
- E->replaceAllUsesWith(UndefValue::get(E->getType()));
- E->eraseFromParent();
- }
-
- // Add a call to describe the actions for this landing pad.
- std::vector<Value *> ActionArgs;
- for (ActionHandler *Action : Actions) {
- // Action codes from docs are: 0 cleanup, 1 catch.
- if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
- ActionArgs.push_back(ConstantInt::get(Int32Type, 1));
- ActionArgs.push_back(CatchAction->getSelector());
- // Find the frame escape index of the exception object alloca in the
- // parent.
- int FrameEscapeIdx = -1;
- Value *EHObj = const_cast<Value *>(CatchAction->getExceptionVar());
- if (EHObj && !isa<ConstantPointerNull>(EHObj)) {
- auto I = FrameVarInfo.find(EHObj);
- assert(I != FrameVarInfo.end() &&
- "failed to map llvm.eh.begincatch var");
- FrameEscapeIdx = std::distance(FrameVarInfo.begin(), I);
- }
- ActionArgs.push_back(ConstantInt::get(Int32Type, FrameEscapeIdx));
- } else {
- ActionArgs.push_back(ConstantInt::get(Int32Type, 0));
- }
- ActionArgs.push_back(Action->getHandlerBlockOrFunc());
- }
- CallInst *Recover =
- CallInst::Create(ActionIntrin, ActionArgs, "recover", LPadBB);
-
- SetVector<BasicBlock *> ReturnTargets;
- for (ActionHandler *Action : Actions) {
- if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
- const auto &CatchTargets = CatchAction->getReturnTargets();
- ReturnTargets.insert(CatchTargets.begin(), CatchTargets.end());
- }
- }
- IndirectBrInst *Branch =
- IndirectBrInst::Create(Recover, ReturnTargets.size(), LPadBB);
- for (BasicBlock *Target : ReturnTargets)
- Branch->addDestination(Target);
-
- if (!isAsynchronousEHPersonality(Personality)) {
- // C++ EH must repopulate the targets later to handle the case of
- // targets that are reached indirectly through nested landing pads.
- LPadImpls.push_back(std::make_pair(Recover, Branch));
- }
-
- } // End for each landingpad
-
- // If nothing got outlined, there is no more processing to be done.
- if (!HandlersOutlined)
+bool WinEHPrepare::runOnFunction(Function &Fn) {
+ if (!Fn.hasPersonalityFn())
return false;
- // Replace any nested landing pad stubs with the correct action handler.
- // This must be done before we remove unreachable blocks because it
- // cleans up references to outlined blocks that will be deleted.
- for (auto &LPadPair : NestedLPtoOriginalLP)
- completeNestedLandingPad(&F, LPadPair.first, LPadPair.second, FrameVarInfo);
- NestedLPtoOriginalLP.clear();
-
- // Update the indirectbr instructions' target lists if necessary.
- SetVector<BasicBlock*> CheckedTargets;
- SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
- for (auto &LPadImplPair : LPadImpls) {
- IntrinsicInst *Recover = cast<IntrinsicInst>(LPadImplPair.first);
- IndirectBrInst *Branch = LPadImplPair.second;
-
- // Get a list of handlers called by
- parseEHActions(Recover, ActionList);
-
- // Add an indirect branch listing possible successors of the catch handlers.
- SetVector<BasicBlock *> ReturnTargets;
- for (const auto &Action : ActionList) {
- if (auto *CA = dyn_cast<CatchHandler>(Action.get())) {
- Function *Handler = cast<Function>(CA->getHandlerBlockOrFunc());
- getPossibleReturnTargets(&F, Handler, ReturnTargets);
- }
- }
- ActionList.clear();
- // Clear any targets we already knew about.
- for (unsigned int I = 0, E = Branch->getNumDestinations(); I < E; ++I) {
- BasicBlock *KnownTarget = Branch->getDestination(I);
- if (ReturnTargets.count(KnownTarget))
- ReturnTargets.remove(KnownTarget);
- }
- for (BasicBlock *Target : ReturnTargets) {
- Branch->addDestination(Target);
- // The target may be a block that we excepted to get pruned.
- // If it is, it may contain a call to llvm.eh.endcatch.
- if (CheckedTargets.insert(Target)) {
- // Earlier preparations guarantee that all calls to llvm.eh.endcatch
- // will be followed by an unconditional branch.
- auto *Br = dyn_cast<BranchInst>(Target->getTerminator());
- if (Br && Br->isUnconditional() &&
- Br != Target->getFirstNonPHIOrDbgOrLifetime()) {
- Instruction *Prev = Br->getPrevNode();
- if (match(cast<Value>(Prev), m_Intrinsic<Intrinsic::eh_endcatch>()))
- Prev->eraseFromParent();
- }
- }
- }
- }
- LPadImpls.clear();
-
- F.addFnAttr("wineh-parent", F.getName());
-
- // Delete any blocks that were only used by handlers that were outlined above.
- removeUnreachableBlocks(F);
-
- BasicBlock *Entry = &F.getEntryBlock();
- IRBuilder<> Builder(F.getParent()->getContext());
- Builder.SetInsertPoint(Entry->getFirstInsertionPt());
-
- Function *FrameEscapeFn =
- Intrinsic::getDeclaration(M, Intrinsic::localescape);
- Function *RecoverFrameFn =
- Intrinsic::getDeclaration(M, Intrinsic::localrecover);
- SmallVector<Value *, 8> AllocasToEscape;
-
- // 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::localescape) {
- auto Args = II->arg_operands();
- AllocasToEscape.append(Args.begin(), Args.end());
- II->eraseFromParent();
- break;
- }
- }
-
- // Finally, replace all of the temporary allocas for frame variables used in
- // the outlined handlers with calls to llvm.localrecover.
- for (auto &VarInfoEntry : FrameVarInfo) {
- Value *ParentVal = VarInfoEntry.first;
- TinyPtrVector<AllocaInst *> &Allocas = VarInfoEntry.second;
- AllocaInst *ParentAlloca = cast<AllocaInst>(ParentVal);
-
- // FIXME: We should try to sink unescaped allocas from the parent frame into
- // the child frame. If the alloca is escaped, we have to use the lifetime
- // markers to ensure that the alloca is only live within the child frame.
-
- // Add this alloca to the list of things to escape.
- AllocasToEscape.push_back(ParentAlloca);
-
- // Next replace all outlined allocas that are mapped to it.
- for (AllocaInst *TempAlloca : Allocas) {
- if (TempAlloca == getCatchObjectSentinel())
- continue; // Skip catch parameter sentinels.
- Function *HandlerFn = TempAlloca->getParent()->getParent();
- llvm::Value *FP = HandlerToParentFP[HandlerFn];
- assert(FP);
-
- // FIXME: Sink this localrecover into the blocks where it is used.
- Builder.SetInsertPoint(TempAlloca);
- Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc());
- Value *RecoverArgs[] = {
- Builder.CreateBitCast(&F, Int8PtrType, ""), FP,
- llvm::ConstantInt::get(Int32Type, AllocasToEscape.size() - 1)};
- Instruction *RecoveredAlloca =
- Builder.CreateCall(RecoverFrameFn, RecoverArgs);
-
- // Add a pointer bitcast if the alloca wasn't an i8.
- if (RecoveredAlloca->getType() != TempAlloca->getType()) {
- RecoveredAlloca->setName(Twine(TempAlloca->getName()) + ".i8");
- RecoveredAlloca = cast<Instruction>(
- Builder.CreateBitCast(RecoveredAlloca, TempAlloca->getType()));
- }
- TempAlloca->replaceAllUsesWith(RecoveredAlloca);
- TempAlloca->removeFromParent();
- RecoveredAlloca->takeName(TempAlloca);
- delete TempAlloca;
- }
- } // End for each FrameVarInfo entry.
-
- // Insert 'call void (...)* @llvm.localescape(...)' at the end of the entry
- // block.
- Builder.SetInsertPoint(&F.getEntryBlock().back());
- Builder.CreateCall(FrameEscapeFn, AllocasToEscape);
-
- if (SEHExceptionCodeSlot) {
- if (isAllocaPromotable(SEHExceptionCodeSlot)) {
- SmallPtrSet<BasicBlock *, 4> UserBlocks;
- for (User *U : SEHExceptionCodeSlot->users()) {
- if (auto *Inst = dyn_cast<Instruction>(U))
- UserBlocks.insert(Inst->getParent());
- }
- PromoteMemToReg(SEHExceptionCodeSlot, *DT);
- // After the promotion, kill off dead instructions.
- for (BasicBlock *BB : UserBlocks)
- SimplifyInstructionsInBlock(BB, LibInfo);
- }
- }
-
- // Clean up the handler action maps we created for this function
- DeleteContainerSeconds(CatchHandlerMap);
- CatchHandlerMap.clear();
- DeleteContainerSeconds(CleanupHandlerMap);
- CleanupHandlerMap.clear();
- HandlerToParentFP.clear();
- DT = nullptr;
- LibInfo = nullptr;
- SEHExceptionCodeSlot = nullptr;
- EHBlocks.clear();
- NormalBlocks.clear();
- EHReturnBlocks.clear();
-
- return HandlersOutlined;
-}
-
-void WinEHPrepare::promoteLandingPadValues(LandingPadInst *LPad) {
- // If the return values of the landing pad instruction are extracted and
- // stored to memory, we want to promote the store locations to reg values.
- SmallVector<AllocaInst *, 2> EHAllocas;
-
- // The landingpad instruction returns an aggregate value. Typically, its
- // value will be passed to a pair of extract value instructions and the
- // results of those extracts are often passed to store instructions.
- // In unoptimized code the stored value will often be loaded and then stored
- // again.
- for (auto *U : LPad->users()) {
- ExtractValueInst *Extract = dyn_cast<ExtractValueInst>(U);
- if (!Extract)
- continue;
-
- for (auto *EU : Extract->users()) {
- if (auto *Store = dyn_cast<StoreInst>(EU)) {
- auto *AV = cast<AllocaInst>(Store->getPointerOperand());
- EHAllocas.push_back(AV);
- }
- }
- }
-
- // We can't do this without a dominator tree.
- assert(DT);
-
- if (!EHAllocas.empty()) {
- PromoteMemToReg(EHAllocas, *DT);
- EHAllocas.clear();
- }
-
- // After promotion, some extracts may be trivially dead. Remove them.
- SmallVector<Value *, 4> Users(LPad->user_begin(), LPad->user_end());
- for (auto *U : Users)
- RecursivelyDeleteTriviallyDeadInstructions(U);
-}
-
-void WinEHPrepare::getPossibleReturnTargets(Function *ParentF,
- Function *HandlerF,
- SetVector<BasicBlock*> &Targets) {
- for (BasicBlock &BB : *HandlerF) {
- // If the handler contains landing pads, check for any
- // handlers that may return directly to a block in the
- // parent function.
- if (auto *LPI = BB.getLandingPadInst()) {
- IntrinsicInst *Recover = cast<IntrinsicInst>(LPI->getNextNode());
- SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
- parseEHActions(Recover, ActionList);
- for (const auto &Action : ActionList) {
- if (auto *CH = dyn_cast<CatchHandler>(Action.get())) {
- Function *NestedF = cast<Function>(CH->getHandlerBlockOrFunc());
- getPossibleReturnTargets(ParentF, NestedF, Targets);
- }
- }
- }
-
- auto *Ret = dyn_cast<ReturnInst>(BB.getTerminator());
- if (!Ret)
- continue;
-
- // Handler functions must always return a block address.
- BlockAddress *BA = cast<BlockAddress>(Ret->getReturnValue());
-
- // If this is the handler for a nested landing pad, the
- // return address may have been remapped to a block in the
- // parent handler. We're not interested in those.
- if (BA->getFunction() != ParentF)
- continue;
-
- Targets.insert(BA->getBasicBlock());
- }
-}
-
-void WinEHPrepare::completeNestedLandingPad(Function *ParentFn,
- LandingPadInst *OutlinedLPad,
- const LandingPadInst *OriginalLPad,
- FrameVarInfoMap &FrameVarInfo) {
- // Get the nested block and erase the unreachable instruction that was
- // temporarily inserted as its terminator.
- LLVMContext &Context = ParentFn->getContext();
- BasicBlock *OutlinedBB = OutlinedLPad->getParent();
- // If the nested landing pad was outlined before the landing pad that enclosed
- // it, it will already be in outlined form. In that case, we just need to see
- // if the returns and the enclosing branch instruction need to be updated.
- IndirectBrInst *Branch =
- dyn_cast<IndirectBrInst>(OutlinedBB->getTerminator());
- if (!Branch) {
- // If the landing pad wasn't in outlined form, it should be a stub with
- // an unreachable terminator.
- assert(isa<UnreachableInst>(OutlinedBB->getTerminator()));
- OutlinedBB->getTerminator()->eraseFromParent();
- // That should leave OutlinedLPad as the last instruction in its block.
- assert(&OutlinedBB->back() == OutlinedLPad);
- }
-
- // The original landing pad will have already had its action intrinsic
- // built by the outlining loop. We need to clone that into the outlined
- // location. It may also be necessary to add references to the exception
- // variables to the outlined handler in which this landing pad is nested
- // and remap return instructions in the nested handlers that should return
- // to an address in the outlined handler.
- Function *OutlinedHandlerFn = OutlinedBB->getParent();
- BasicBlock::const_iterator II = OriginalLPad;
- ++II;
- // The instruction after the landing pad should now be a call to eh.actions.
- const Instruction *Recover = II;
- const IntrinsicInst *EHActions = cast<IntrinsicInst>(Recover);
-
- // Remap the return target in the nested handler.
- SmallVector<BlockAddress *, 4> ActionTargets;
- SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
- parseEHActions(EHActions, ActionList);
- for (const auto &Action : ActionList) {
- auto *Catch = dyn_cast<CatchHandler>(Action.get());
- if (!Catch)
- continue;
- // The dyn_cast to function here selects C++ catch handlers and skips
- // SEH catch handlers.
- auto *Handler = dyn_cast<Function>(Catch->getHandlerBlockOrFunc());
- if (!Handler)
- continue;
- // Visit all the return instructions, looking for places that return
- // to a location within OutlinedHandlerFn.
- for (BasicBlock &NestedHandlerBB : *Handler) {
- auto *Ret = dyn_cast<ReturnInst>(NestedHandlerBB.getTerminator());
- if (!Ret)
- continue;
-
- // Handler functions must always return a block address.
- BlockAddress *BA = cast<BlockAddress>(Ret->getReturnValue());
- // The original target will have been in the main parent function,
- // but if it is the address of a block that has been outlined, it
- // should be a block that was outlined into OutlinedHandlerFn.
- assert(BA->getFunction() == ParentFn);
-
- // Ignore targets that aren't part of an outlined handler function.
- if (!LPadTargetBlocks.count(BA->getBasicBlock()))
- continue;
-
- // If the return value is the address ofF a block that we
- // previously outlined into the parent handler function, replace
- // the return instruction and add the mapped target to the list
- // of possible return addresses.
- BasicBlock *MappedBB = LPadTargetBlocks[BA->getBasicBlock()];
- assert(MappedBB->getParent() == OutlinedHandlerFn);
- BlockAddress *NewBA = BlockAddress::get(OutlinedHandlerFn, MappedBB);
- Ret->eraseFromParent();
- ReturnInst::Create(Context, NewBA, &NestedHandlerBB);
- ActionTargets.push_back(NewBA);
- }
- }
- ActionList.clear();
-
- if (Branch) {
- // If the landing pad was already in outlined form, just update its targets.
- for (unsigned int I = Branch->getNumDestinations(); I > 0; --I)
- Branch->removeDestination(I);
- // Add the previously collected action targets.
- for (auto *Target : ActionTargets)
- Branch->addDestination(Target->getBasicBlock());
- } else {
- // If the landing pad was previously stubbed out, fill in its outlined form.
- IntrinsicInst *NewEHActions = cast<IntrinsicInst>(EHActions->clone());
- OutlinedBB->getInstList().push_back(NewEHActions);
-
- // Insert an indirect branch into the outlined landing pad BB.
- IndirectBrInst *IBr = IndirectBrInst::Create(NewEHActions, 0, OutlinedBB);
- // Add the previously collected action targets.
- for (auto *Target : ActionTargets)
- IBr->addDestination(Target->getBasicBlock());
- }
-}
-
-// This function examines a block to determine whether the block ends with a
-// conditional branch to a catch handler based on a selector comparison.
-// This function is used both by the WinEHPrepare::findSelectorComparison() and
-// WinEHCleanupDirector::handleTypeIdFor().
-static bool isSelectorDispatch(BasicBlock *BB, BasicBlock *&CatchHandler,
- Constant *&Selector, BasicBlock *&NextBB) {
- ICmpInst::Predicate Pred;
- BasicBlock *TBB, *FBB;
- Value *LHS, *RHS;
-
- if (!match(BB->getTerminator(),
- m_Br(m_ICmp(Pred, m_Value(LHS), m_Value(RHS)), TBB, FBB)))
- return false;
+ // Classify the personality to see what kind of preparation we need.
+ Personality = classifyEHPersonality(Fn.getPersonalityFn());
- if (!match(LHS,
- m_Intrinsic<Intrinsic::eh_typeid_for>(m_Constant(Selector))) &&
- !match(RHS, m_Intrinsic<Intrinsic::eh_typeid_for>(m_Constant(Selector))))
+ // Do nothing if this is not a funclet-based personality.
+ if (!isFuncletEHPersonality(Personality))
return false;
- if (Pred == CmpInst::ICMP_EQ) {
- CatchHandler = TBB;
- NextBB = FBB;
- return true;
- }
-
- if (Pred == CmpInst::ICMP_NE) {
- CatchHandler = FBB;
- NextBB = TBB;
- return true;
- }
-
- return false;
-}
-
-static bool isCatchBlock(BasicBlock *BB) {
- for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
- II != IE; ++II) {
- if (match(cast<Value>(II), m_Intrinsic<Intrinsic::eh_begincatch>()))
- return true;
- }
- return false;
-}
-
-static BasicBlock *createStubLandingPad(Function *Handler) {
- // FIXME: Finish this!
- LLVMContext &Context = Handler->getContext();
- BasicBlock *StubBB = BasicBlock::Create(Context, "stub");
- Handler->getBasicBlockList().push_back(StubBB);
- IRBuilder<> Builder(StubBB);
- LandingPadInst *LPad = Builder.CreateLandingPad(
- llvm::StructType::get(Type::getInt8PtrTy(Context),
- Type::getInt32Ty(Context), nullptr),
- 0);
- // Insert a call to llvm.eh.actions so that we don't try to outline this lpad.
- Function *ActionIntrin =
- Intrinsic::getDeclaration(Handler->getParent(), Intrinsic::eh_actions);
- Builder.CreateCall(ActionIntrin, {}, "recover");
- LPad->setCleanup(true);
- Builder.CreateUnreachable();
- return StubBB;
-}
-
-// Cycles through the blocks in an outlined handler function looking for an
-// invoke instruction and inserts an invoke of llvm.donothing with an empty
-// landing pad if none is found. The code that generates the .xdata tables for
-// the handler needs at least one landing pad to identify the parent function's
-// personality.
-void WinEHPrepare::addStubInvokeToHandlerIfNeeded(Function *Handler) {
- ReturnInst *Ret = nullptr;
- UnreachableInst *Unreached = nullptr;
- for (BasicBlock &BB : *Handler) {
- TerminatorInst *Terminator = BB.getTerminator();
- // If we find an invoke, there is nothing to be done.
- auto *II = dyn_cast<InvokeInst>(Terminator);
- if (II)
- return;
- // If we've already recorded a return instruction, keep looking for invokes.
- if (!Ret)
- Ret = dyn_cast<ReturnInst>(Terminator);
- // If we haven't recorded an unreachable instruction, try this terminator.
- if (!Unreached)
- Unreached = dyn_cast<UnreachableInst>(Terminator);
- }
-
- // If we got this far, the handler contains no invokes. We should have seen
- // at least one return or unreachable instruction. We'll insert an invoke of
- // llvm.donothing ahead of that instruction.
- assert(Ret || Unreached);
- TerminatorInst *Term;
- if (Ret)
- Term = Ret;
- else
- Term = Unreached;
- BasicBlock *OldRetBB = Term->getParent();
- BasicBlock *NewRetBB = SplitBlock(OldRetBB, Term, DT);
- // SplitBlock adds an unconditional branch instruction at the end of the
- // parent block. We want to replace that with an invoke call, so we can
- // erase it now.
- OldRetBB->getTerminator()->eraseFromParent();
- BasicBlock *StubLandingPad = createStubLandingPad(Handler);
- Function *F =
- Intrinsic::getDeclaration(Handler->getParent(), Intrinsic::donothing);
- InvokeInst::Create(F, NewRetBB, StubLandingPad, None, "", OldRetBB);
-}
-
-// 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(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 *ArgTys[2] = {Int8PtrType, Int8PtrType};
- FnType = FunctionType::get(RetTy, ArgTys, false);
- } else {
- FnType = FunctionType::get(RetTy, None, false);
- }
-
- Function *Handler =
- Function::Create(FnType, GlobalVariable::InternalLinkage, Name, M);
- BasicBlock *Entry = BasicBlock::Create(Context, "entry");
- Handler->getBasicBlockList().push_front(Entry);
- if (TheTriple.getArch() == Triple::x86_64) {
- ParentFP = &(Handler->getArgumentList().back());
- } else {
- assert(M);
- Function *FrameAddressFn =
- Intrinsic::getDeclaration(M, Intrinsic::frameaddress);
- 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;
-}
-
-bool WinEHPrepare::outlineHandler(ActionHandler *Action, Function *SrcFn,
- LandingPadInst *LPad, BasicBlock *StartBB,
- FrameVarInfoMap &VarInfo) {
- Module *M = SrcFn->getParent();
- LLVMContext &Context = M->getContext();
- Type *Int8PtrType = Type::getInt8PtrTy(Context);
-
- // Create a new function to receive the handler contents.
- Value *ParentFP;
- Function *Handler;
- if (Action->getType() == Catch) {
- Handler = createHandlerFunc(SrcFn, Int8PtrType, SrcFn->getName() + ".catch", M,
- ParentFP);
- } else {
- Handler = createHandlerFunc(SrcFn, Type::getVoidTy(Context),
- SrcFn->getName() + ".cleanup", M, ParentFP);
- }
- Handler->setPersonalityFn(SrcFn->getPersonalityFn());
- HandlerToParentFP[Handler] = ParentFP;
- Handler->addFnAttr("wineh-parent", SrcFn->getName());
- BasicBlock *Entry = &Handler->getEntryBlock();
-
- // Generate a standard prolog to setup the frame recovery structure.
- IRBuilder<> Builder(Context);
- Builder.SetInsertPoint(Entry);
- Builder.SetCurrentDebugLocation(LPad->getDebugLoc());
-
- std::unique_ptr<WinEHCloningDirectorBase> Director;
-
- ValueToValueMapTy VMap;
-
- LandingPadMap &LPadMap = LPadMaps[LPad];
- if (!LPadMap.isInitialized())
- LPadMap.mapLandingPad(LPad);
- if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
- Constant *Sel = CatchAction->getSelector();
- Director.reset(new WinEHCatchDirector(Handler, ParentFP, Sel, VarInfo,
- LPadMap, NestedLPtoOriginalLP, DT,
- EHBlocks));
- LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType),
- ConstantInt::get(Type::getInt32Ty(Context), 1));
- } else {
- Director.reset(
- new WinEHCleanupDirector(Handler, ParentFP, VarInfo, LPadMap));
- LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType),
- UndefValue::get(Type::getInt32Ty(Context)));
- }
-
- SmallVector<ReturnInst *, 8> Returns;
- ClonedCodeInfo OutlinedFunctionInfo;
-
- // If the start block contains PHI nodes, we need to map them.
- BasicBlock::iterator II = StartBB->begin();
- while (auto *PN = dyn_cast<PHINode>(II)) {
- bool Mapped = false;
- // Look for PHI values that we have already mapped (such as the selector).
- for (Value *Val : PN->incoming_values()) {
- if (VMap.count(Val)) {
- VMap[PN] = VMap[Val];
- Mapped = true;
- }
- }
- // If we didn't find a match for this value, map it as an undef.
- if (!Mapped) {
- VMap[PN] = UndefValue::get(PN->getType());
- }
- ++II;
- }
-
- // The landing pad value may be used by PHI nodes. It will ultimately be
- // eliminated, but we need it in the map for intermediate handling.
- VMap[LPad] = UndefValue::get(LPad->getType());
-
- // Skip over PHIs and, if applicable, landingpad instructions.
- II = StartBB->getFirstInsertionPt();
-
- CloneAndPruneIntoFromInst(Handler, SrcFn, II, VMap,
- /*ModuleLevelChanges=*/false, Returns, "",
- &OutlinedFunctionInfo, Director.get());
-
- // Move all the instructions in the cloned "entry" block into our entry block.
- // Depending on how the parent function was laid out, the block that will
- // correspond to the outlined entry block may not be the first block in the
- // list. We can recognize it, however, as the cloned block which has no
- // predecessors. Any other block wouldn't have been cloned if it didn't
- // have a predecessor which was also cloned.
- Function::iterator ClonedIt = std::next(Function::iterator(Entry));
- while (!pred_empty(ClonedIt))
- ++ClonedIt;
- BasicBlock *ClonedEntryBB = ClonedIt;
- assert(ClonedEntryBB);
- Entry->getInstList().splice(Entry->end(), ClonedEntryBB->getInstList());
- ClonedEntryBB->eraseFromParent();
-
- // Make sure we can identify the handler's personality later.
- addStubInvokeToHandlerIfNeeded(Handler);
-
- if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
- WinEHCatchDirector *CatchDirector =
- reinterpret_cast<WinEHCatchDirector *>(Director.get());
- CatchAction->setExceptionVar(CatchDirector->getExceptionVar());
- CatchAction->setReturnTargets(CatchDirector->getReturnTargets());
-
- // Look for blocks that are not part of the landing pad that we just
- // outlined but terminate with a call to llvm.eh.endcatch and a
- // branch to a block that is in the handler we just outlined.
- // These blocks will be part of a nested landing pad that intends to
- // return to an address in this handler. This case is best handled
- // after both landing pads have been outlined, so for now we'll just
- // save the association of the blocks in LPadTargetBlocks. The
- // return instructions which are created from these branches will be
- // replaced after all landing pads have been outlined.
- for (const auto MapEntry : VMap) {
- // VMap maps all values and blocks that were just cloned, but dead
- // blocks which were pruned will map to nullptr.
- if (!isa<BasicBlock>(MapEntry.first) || MapEntry.second == nullptr)
- continue;
- const BasicBlock *MappedBB = cast<BasicBlock>(MapEntry.first);
- for (auto *Pred : predecessors(const_cast<BasicBlock *>(MappedBB))) {
- auto *Branch = dyn_cast<BranchInst>(Pred->getTerminator());
- if (!Branch || !Branch->isUnconditional() || Pred->size() <= 1)
- continue;
- BasicBlock::iterator II = const_cast<BranchInst *>(Branch);
- --II;
- if (match(cast<Value>(II), m_Intrinsic<Intrinsic::eh_endcatch>())) {
- // This would indicate that a nested landing pad wants to return
- // to a block that is outlined into two different handlers.
- assert(!LPadTargetBlocks.count(MappedBB));
- LPadTargetBlocks[MappedBB] = cast<BasicBlock>(MapEntry.second);
- }
- }
- }
- } // End if (CatchAction)
-
- Action->setHandlerBlockOrFunc(Handler);
-
- return true;
-}
-
-/// This BB must end in a selector dispatch. All we need to do is pass the
-/// handler block to llvm.eh.actions and list it as a possible indirectbr
-/// target.
-void WinEHPrepare::processSEHCatchHandler(CatchHandler *CatchAction,
- BasicBlock *StartBB) {
- BasicBlock *HandlerBB;
- BasicBlock *NextBB;
- Constant *Selector;
- bool Res = isSelectorDispatch(StartBB, HandlerBB, Selector, NextBB);
- if (Res) {
- // If this was EH dispatch, this must be a conditional branch to the handler
- // block.
- // FIXME: Handle instructions in the dispatch block. Currently we drop them,
- // leading to crashes if some optimization hoists stuff here.
- assert(CatchAction->getSelector() && HandlerBB &&
- "expected catch EH dispatch");
- } else {
- // This must be a catch-all. Split the block after the landingpad.
- assert(CatchAction->getSelector()->isNullValue() && "expected catch-all");
- HandlerBB = SplitBlock(StartBB, StartBB->getFirstInsertionPt(), DT);
- }
- IRBuilder<> Builder(HandlerBB->getFirstInsertionPt());
- Function *EHCodeFn = Intrinsic::getDeclaration(
- StartBB->getParent()->getParent(), Intrinsic::eh_exceptioncode);
- Value *Code = Builder.CreateCall(EHCodeFn, {}, "sehcode");
- Code = Builder.CreateIntToPtr(Code, SEHExceptionCodeSlot->getAllocatedType());
- Builder.CreateStore(Code, SEHExceptionCodeSlot);
- CatchAction->setHandlerBlockOrFunc(BlockAddress::get(HandlerBB));
- TinyPtrVector<BasicBlock *> Targets(HandlerBB);
- CatchAction->setReturnTargets(Targets);
-}
-
-void LandingPadMap::mapLandingPad(const LandingPadInst *LPad) {
- // Each instance of this class should only ever be used to map a single
- // landing pad.
- assert(OriginLPad == nullptr || OriginLPad == LPad);
-
- // If the landing pad has already been mapped, there's nothing more to do.
- if (OriginLPad == LPad)
- return;
-
- OriginLPad = LPad;
-
- // The landingpad instruction returns an aggregate value. Typically, its
- // value will be passed to a pair of extract value instructions and the
- // results of those extracts will have been promoted to reg values before
- // this routine is called.
- for (auto *U : LPad->users()) {
- const ExtractValueInst *Extract = dyn_cast<ExtractValueInst>(U);
- if (!Extract)
- continue;
- assert(Extract->getNumIndices() == 1 &&
- "Unexpected operation: extracting both landing pad values");
- unsigned int Idx = *(Extract->idx_begin());
- assert((Idx == 0 || Idx == 1) &&
- "Unexpected operation: extracting an unknown landing pad element");
- if (Idx == 0) {
- ExtractedEHPtrs.push_back(Extract);
- } else if (Idx == 1) {
- ExtractedSelectors.push_back(Extract);
- }
- }
-}
-
-bool LandingPadMap::isOriginLandingPadBlock(const BasicBlock *BB) const {
- return BB->getLandingPadInst() == OriginLPad;
-}
-
-bool LandingPadMap::isLandingPadSpecificInst(const Instruction *Inst) const {
- if (Inst == OriginLPad)
- return true;
- for (auto *Extract : ExtractedEHPtrs) {
- if (Inst == Extract)
- return true;
- }
- for (auto *Extract : ExtractedSelectors) {
- if (Inst == Extract)
- return true;
- }
- return false;
-}
-
-void LandingPadMap::remapEHValues(ValueToValueMapTy &VMap, Value *EHPtrValue,
- Value *SelectorValue) const {
- // Remap all landing pad extract instructions to the specified values.
- for (auto *Extract : ExtractedEHPtrs)
- VMap[Extract] = EHPtrValue;
- for (auto *Extract : ExtractedSelectors)
- VMap[Extract] = SelectorValue;
-}
-
-static bool isLocalAddressCall(const Value *V) {
- return match(const_cast<Value *>(V), m_Intrinsic<Intrinsic::localaddress>());
-}
-
-CloningDirector::CloningAction WinEHCloningDirectorBase::handleInstruction(
- ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
- // If this is one of the boilerplate landing pad instructions, skip it.
- // The instruction will have already been remapped in VMap.
- if (LPadMap.isLandingPadSpecificInst(Inst))
- return CloningDirector::SkipInstruction;
-
- // Nested landing pads that have not already been outlined will be cloned as
- // stubs, with just the landingpad instruction and an unreachable instruction.
- // When all landingpads have been outlined, we'll replace this with the
- // llvm.eh.actions call and indirect branch created when the landing pad was
- // outlined.
- if (auto *LPad = dyn_cast<LandingPadInst>(Inst)) {
- return handleLandingPad(VMap, LPad, NewBB);
- }
-
- // Nested landing pads that have already been outlined will be cloned in their
- // outlined form, but we need to intercept the ibr instruction to filter out
- // targets that do not return to the handler we are outlining.
- if (auto *IBr = dyn_cast<IndirectBrInst>(Inst)) {
- return handleIndirectBr(VMap, IBr, NewBB);
- }
-
- if (auto *Invoke = dyn_cast<InvokeInst>(Inst))
- return handleInvoke(VMap, Invoke, NewBB);
-
- if (auto *Resume = dyn_cast<ResumeInst>(Inst))
- return handleResume(VMap, Resume, NewBB);
-
- if (auto *Cmp = dyn_cast<CmpInst>(Inst))
- return handleCompare(VMap, Cmp, NewBB);
-
- if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>()))
- return handleBeginCatch(VMap, Inst, NewBB);
- if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>()))
- return handleEndCatch(VMap, Inst, NewBB);
- if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>()))
- return handleTypeIdFor(VMap, Inst, NewBB);
-
- // When outlining llvm.localaddress(), remap that to the second argument,
- // which is the FP of the parent.
- if (isLocalAddressCall(Inst)) {
- VMap[Inst] = ParentFP;
- return CloningDirector::SkipInstruction;
- }
-
- // Continue with the default cloning behavior.
- return CloningDirector::CloneInstruction;
-}
-
-CloningDirector::CloningAction WinEHCatchDirector::handleLandingPad(
- ValueToValueMapTy &VMap, const LandingPadInst *LPad, BasicBlock *NewBB) {
- // If the instruction after the landing pad is a call to llvm.eh.actions
- // the landing pad has already been outlined. In this case, we should
- // clone it because it may return to a block in the handler we are
- // outlining now that would otherwise be unreachable. The landing pads
- // are sorted before outlining begins to enable this case to work
- // properly.
- const Instruction *NextI = LPad->getNextNode();
- if (match(NextI, m_Intrinsic<Intrinsic::eh_actions>()))
- return CloningDirector::CloneInstruction;
-
- // If the landing pad hasn't been outlined yet, the landing pad we are
- // outlining now does not dominate it and so it cannot return to a block
- // in this handler. In that case, we can just insert a stub landing
- // pad now and patch it up later.
- Instruction *NewInst = LPad->clone();
- if (LPad->hasName())
- NewInst->setName(LPad->getName());
- // Save this correlation for later processing.
- NestedLPtoOriginalLP[cast<LandingPadInst>(NewInst)] = LPad;
- VMap[LPad] = NewInst;
- BasicBlock::InstListType &InstList = NewBB->getInstList();
- InstList.push_back(NewInst);
- InstList.push_back(new UnreachableInst(NewBB->getContext()));
- return CloningDirector::StopCloningBB;
-}
-
-CloningDirector::CloningAction WinEHCatchDirector::handleBeginCatch(
- ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
- // The argument to the call is some form of the first element of the
- // landingpad aggregate value, but that doesn't matter. It isn't used
- // here.
- // The second argument is an outparameter where the exception object will be
- // stored. Typically the exception object is a scalar, but it can be an
- // aggregate when catching by value.
- // FIXME: Leave something behind to indicate where the exception object lives
- // for this handler. Should it be part of llvm.eh.actions?
- assert(ExceptionObjectVar == nullptr && "Multiple calls to "
- "llvm.eh.begincatch found while "
- "outlining catch handler.");
- ExceptionObjectVar = Inst->getOperand(1)->stripPointerCasts();
- if (isa<ConstantPointerNull>(ExceptionObjectVar))
- return CloningDirector::SkipInstruction;
- assert(cast<AllocaInst>(ExceptionObjectVar)->isStaticAlloca() &&
- "catch parameter is not static alloca");
- Materializer.escapeCatchObject(ExceptionObjectVar);
- return CloningDirector::SkipInstruction;
-}
-
-CloningDirector::CloningAction
-WinEHCatchDirector::handleEndCatch(ValueToValueMapTy &VMap,
- const Instruction *Inst, BasicBlock *NewBB) {
- auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
- // It might be interesting to track whether or not we are inside a catch
- // function, but that might make the algorithm more brittle than it needs
- // to be.
-
- // The end catch call can occur in one of two places: either in a
- // landingpad block that is part of the catch handlers exception mechanism,
- // or at the end of the catch block. However, a catch-all handler may call
- // end catch from the original landing pad. If the call occurs in a nested
- // landing pad block, we must skip it and continue so that the landing pad
- // gets cloned.
- auto *ParentBB = IntrinCall->getParent();
- if (ParentBB->isLandingPad() && !LPadMap.isOriginLandingPadBlock(ParentBB))
- return CloningDirector::SkipInstruction;
-
- // If an end catch occurs anywhere else we want to terminate the handler
- // with a return to the code that follows the endcatch call. If the
- // next instruction is not an unconditional branch, we need to split the
- // block to provide a clear target for the return instruction.
- BasicBlock *ContinueBB;
- auto Next = std::next(BasicBlock::const_iterator(IntrinCall));
- const BranchInst *Branch = dyn_cast<BranchInst>(Next);
- if (!Branch || !Branch->isUnconditional()) {
- // We're interrupting the cloning process at this location, so the
- // const_cast we're doing here will not cause a problem.
- ContinueBB = SplitBlock(const_cast<BasicBlock *>(ParentBB),
- const_cast<Instruction *>(cast<Instruction>(Next)));
- } else {
- ContinueBB = Branch->getSuccessor(0);
- }
-
- ReturnInst::Create(NewBB->getContext(), BlockAddress::get(ContinueBB), NewBB);
- ReturnTargets.push_back(ContinueBB);
-
- // We just added a terminator to the cloned block.
- // Tell the caller to stop processing the current basic block so that
- // the branch instruction will be skipped.
- return CloningDirector::StopCloningBB;
-}
-
-CloningDirector::CloningAction WinEHCatchDirector::handleTypeIdFor(
- ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
- auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
- Value *Selector = IntrinCall->getArgOperand(0)->stripPointerCasts();
- // This causes a replacement that will collapse the landing pad CFG based
- // on the filter function we intend to match.
- if (Selector == CurrentSelector)
- VMap[Inst] = ConstantInt::get(SelectorIDType, 1);
- else
- VMap[Inst] = ConstantInt::get(SelectorIDType, 0);
- // Tell the caller not to clone this instruction.
- return CloningDirector::SkipInstruction;
-}
-
-CloningDirector::CloningAction WinEHCatchDirector::handleIndirectBr(
- ValueToValueMapTy &VMap,
- const IndirectBrInst *IBr,
- BasicBlock *NewBB) {
- // If this indirect branch is not part of a landing pad block, just clone it.
- const BasicBlock *ParentBB = IBr->getParent();
- if (!ParentBB->isLandingPad())
- return CloningDirector::CloneInstruction;
-
- // If it is part of a landing pad, we want to filter out target blocks
- // that are not part of the handler we are outlining.
- const LandingPadInst *LPad = ParentBB->getLandingPadInst();
-
- // Save this correlation for later processing.
- NestedLPtoOriginalLP[cast<LandingPadInst>(VMap[LPad])] = LPad;
-
- // We should only get here for landing pads that have already been outlined.
- assert(match(LPad->getNextNode(), m_Intrinsic<Intrinsic::eh_actions>()));
-
- // Copy the indirectbr, but only include targets that were previously
- // identified as EH blocks and are dominated by the nested landing pad.
- SetVector<const BasicBlock *> ReturnTargets;
- for (int I = 0, E = IBr->getNumDestinations(); I < E; ++I) {
- auto *TargetBB = IBr->getDestination(I);
- if (EHBlocks.count(const_cast<BasicBlock*>(TargetBB)) &&
- DT->dominates(ParentBB, TargetBB)) {
- DEBUG(dbgs() << " Adding destination " << TargetBB->getName() << "\n");
- ReturnTargets.insert(TargetBB);
- }
- }
- IndirectBrInst *NewBranch =
- IndirectBrInst::Create(const_cast<Value *>(IBr->getAddress()),
- ReturnTargets.size(), NewBB);
- for (auto *Target : ReturnTargets)
- NewBranch->addDestination(const_cast<BasicBlock*>(Target));
-
- // The operands and targets of the branch instruction are remapped later
- // because it is a terminator. Tell the cloning code to clone the
- // blocks we just added to the target list.
- return CloningDirector::CloneSuccessors;
-}
-
-CloningDirector::CloningAction
-WinEHCatchDirector::handleInvoke(ValueToValueMapTy &VMap,
- const InvokeInst *Invoke, BasicBlock *NewBB) {
- return CloningDirector::CloneInstruction;
-}
-
-CloningDirector::CloningAction
-WinEHCatchDirector::handleResume(ValueToValueMapTy &VMap,
- const ResumeInst *Resume, BasicBlock *NewBB) {
- // Resume instructions shouldn't be reachable from catch handlers.
- // We still need to handle it, but it will be pruned.
- BasicBlock::InstListType &InstList = NewBB->getInstList();
- InstList.push_back(new UnreachableInst(NewBB->getContext()));
- return CloningDirector::StopCloningBB;
-}
-
-CloningDirector::CloningAction
-WinEHCatchDirector::handleCompare(ValueToValueMapTy &VMap,
- const CmpInst *Compare, BasicBlock *NewBB) {
- const IntrinsicInst *IntrinCall = nullptr;
- if (match(Compare->getOperand(0), m_Intrinsic<Intrinsic::eh_typeid_for>())) {
- IntrinCall = dyn_cast<IntrinsicInst>(Compare->getOperand(0));
- } else if (match(Compare->getOperand(1),
- m_Intrinsic<Intrinsic::eh_typeid_for>())) {
- IntrinCall = dyn_cast<IntrinsicInst>(Compare->getOperand(1));
- }
- if (IntrinCall) {
- Value *Selector = IntrinCall->getArgOperand(0)->stripPointerCasts();
- // This causes a replacement that will collapse the landing pad CFG based
- // on the filter function we intend to match.
- if (Selector == CurrentSelector->stripPointerCasts()) {
- VMap[Compare] = ConstantInt::get(SelectorIDType, 1);
- } else {
- VMap[Compare] = ConstantInt::get(SelectorIDType, 0);
- }
- return CloningDirector::SkipInstruction;
- }
- return CloningDirector::CloneInstruction;
-}
-
-CloningDirector::CloningAction WinEHCleanupDirector::handleLandingPad(
- ValueToValueMapTy &VMap, const LandingPadInst *LPad, BasicBlock *NewBB) {
- // The MS runtime will terminate the process if an exception occurs in a
- // cleanup handler, so we shouldn't encounter landing pads in the actual
- // cleanup code, but they may appear in catch blocks. Depending on where
- // we started cloning we may see one, but it will get dropped during dead
- // block pruning.
- Instruction *NewInst = new UnreachableInst(NewBB->getContext());
- VMap[LPad] = NewInst;
- BasicBlock::InstListType &InstList = NewBB->getInstList();
- InstList.push_back(NewInst);
- return CloningDirector::StopCloningBB;
-}
-
-CloningDirector::CloningAction WinEHCleanupDirector::handleBeginCatch(
- ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
- // Cleanup code may flow into catch blocks or the catch block may be part
- // of a branch that will be optimized away. We'll insert a return
- // instruction now, but it may be pruned before the cloning process is
- // complete.
- ReturnInst::Create(NewBB->getContext(), nullptr, NewBB);
- return CloningDirector::StopCloningBB;
-}
-
-CloningDirector::CloningAction WinEHCleanupDirector::handleEndCatch(
- ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
- // Cleanup handlers nested within catch handlers may begin with a call to
- // eh.endcatch. We can just ignore that instruction.
- return CloningDirector::SkipInstruction;
-}
-
-CloningDirector::CloningAction WinEHCleanupDirector::handleTypeIdFor(
- ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
- // If we encounter a selector comparison while cloning a cleanup handler,
- // we want to stop cloning immediately. Anything after the dispatch
- // will be outlined into a different handler.
- BasicBlock *CatchHandler;
- Constant *Selector;
- BasicBlock *NextBB;
- if (isSelectorDispatch(const_cast<BasicBlock *>(Inst->getParent()),
- CatchHandler, Selector, NextBB)) {
- ReturnInst::Create(NewBB->getContext(), nullptr, NewBB);
- return CloningDirector::StopCloningBB;
- }
- // If eg.typeid.for is called for any other reason, it can be ignored.
- VMap[Inst] = ConstantInt::get(SelectorIDType, 0);
- return CloningDirector::SkipInstruction;
-}
-
-CloningDirector::CloningAction WinEHCleanupDirector::handleIndirectBr(
- ValueToValueMapTy &VMap,
- const IndirectBrInst *IBr,
- BasicBlock *NewBB) {
- // No special handling is required for cleanup cloning.
- return CloningDirector::CloneInstruction;
-}
-
-CloningDirector::CloningAction WinEHCleanupDirector::handleInvoke(
- ValueToValueMapTy &VMap, const InvokeInst *Invoke, BasicBlock *NewBB) {
- // All invokes in cleanup handlers can be replaced with calls.
- SmallVector<Value *, 16> CallArgs(Invoke->op_begin(), Invoke->op_end() - 3);
- // Insert a normal call instruction...
- CallInst *NewCall =
- CallInst::Create(const_cast<Value *>(Invoke->getCalledValue()), CallArgs,
- Invoke->getName(), NewBB);
- NewCall->setCallingConv(Invoke->getCallingConv());
- NewCall->setAttributes(Invoke->getAttributes());
- NewCall->setDebugLoc(Invoke->getDebugLoc());
- VMap[Invoke] = NewCall;
-
- // Remap the operands.
- llvm::RemapInstruction(NewCall, VMap, RF_None, nullptr, &Materializer);
-
- // Insert an unconditional branch to the normal destination.
- BranchInst::Create(Invoke->getNormalDest(), NewBB);
-
- // The unwind destination won't be cloned into the new function, so
- // we don't need to clean up its phi nodes.
-
- // We just added a terminator to the cloned block.
- // Tell the caller to stop processing the current basic block.
- return CloningDirector::CloneSuccessors;
-}
-
-CloningDirector::CloningAction WinEHCleanupDirector::handleResume(
- ValueToValueMapTy &VMap, const ResumeInst *Resume, BasicBlock *NewBB) {
- ReturnInst::Create(NewBB->getContext(), nullptr, NewBB);
-
- // We just added a terminator to the cloned block.
- // Tell the caller to stop processing the current basic block so that
- // the branch instruction will be skipped.
- return CloningDirector::StopCloningBB;
-}
-
-CloningDirector::CloningAction
-WinEHCleanupDirector::handleCompare(ValueToValueMapTy &VMap,
- const CmpInst *Compare, BasicBlock *NewBB) {
- if (match(Compare->getOperand(0), m_Intrinsic<Intrinsic::eh_typeid_for>()) ||
- match(Compare->getOperand(1), m_Intrinsic<Intrinsic::eh_typeid_for>())) {
- VMap[Compare] = ConstantInt::get(SelectorIDType, 1);
- return CloningDirector::SkipInstruction;
- }
- return CloningDirector::CloneInstruction;
-}
-
-WinEHFrameVariableMaterializer::WinEHFrameVariableMaterializer(
- Function *OutlinedFn, Value *ParentFP, FrameVarInfoMap &FrameVarInfo)
- : FrameVarInfo(FrameVarInfo), Builder(OutlinedFn->getContext()) {
- BasicBlock *EntryBB = &OutlinedFn->getEntryBlock();
-
- // New allocas should be inserted in the entry block, but after the parent FP
- // is established if it is an instruction.
- Instruction *InsertPoint = EntryBB->getFirstInsertionPt();
- if (auto *FPInst = dyn_cast<Instruction>(ParentFP))
- InsertPoint = FPInst->getNextNode();
- Builder.SetInsertPoint(EntryBB, InsertPoint);
-}
-
-Value *WinEHFrameVariableMaterializer::materializeValueFor(Value *V) {
- // 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.localrecover.
- if (auto *AV = dyn_cast<AllocaInst>(V)) {
- assert(AV->isStaticAlloca() &&
- "cannot materialize un-demoted dynamic alloca");
- AllocaInst *NewAlloca = dyn_cast<AllocaInst>(AV->clone());
- Builder.Insert(NewAlloca, AV->getName());
- FrameVarInfo[AV].push_back(NewAlloca);
- return NewAlloca;
- }
-
- if (isa<Instruction>(V) || isa<Argument>(V)) {
- Function *Parent = isa<Instruction>(V)
- ? cast<Instruction>(V)->getParent()->getParent()
- : cast<Argument>(V)->getParent();
- errs()
- << "Failed to demote instruction used in exception handler of function "
- << GlobalValue::getRealLinkageName(Parent->getName()) << ":\n";
- errs() << " " << *V << '\n';
- report_fatal_error("WinEHPrepare failed to demote instruction");
- }
-
- // Don't materialize other values.
- return nullptr;
-}
-
-void WinEHFrameVariableMaterializer::escapeCatchObject(Value *V) {
- // Catch parameter objects have to live in the parent frame. When we see a use
- // 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.localescape.
- FrameVarInfo[V].push_back(getCatchObjectSentinel());
-}
-
-// This function maps the catch and cleanup handlers that are reachable from the
-// specified landing pad. The landing pad sequence will have this basic shape:
-//
-// <cleanup handler>
-// <selector comparison>
-// <catch handler>
-// <cleanup handler>
-// <selector comparison>
-// <catch handler>
-// <cleanup handler>
-// ...
-//
-// Any of the cleanup slots may be absent. The cleanup slots may be occupied by
-// any arbitrary control flow, but all paths through the cleanup code must
-// eventually reach the next selector comparison and no path can skip to a
-// different selector comparisons, though some paths may terminate abnormally.
-// Therefore, we will use a depth first search from the start of any given
-// cleanup block and stop searching when we find the next selector comparison.
-//
-// If the landingpad instruction does not have a catch clause, we will assume
-// that any instructions other than selector comparisons and catch handlers can
-// be ignored. In practice, these will only be the boilerplate instructions.
-//
-// The catch handlers may also have any control structure, but we are only
-// interested in the start of the catch handlers, so we don't need to actually
-// follow the flow of the catch handlers. The start of the catch handlers can
-// be located from the compare instructions, but they can be skipped in the
-// flow by following the contrary branch.
-void WinEHPrepare::mapLandingPadBlocks(LandingPadInst *LPad,
- LandingPadActions &Actions) {
- unsigned int NumClauses = LPad->getNumClauses();
- unsigned int HandlersFound = 0;
- BasicBlock *BB = LPad->getParent();
-
- DEBUG(dbgs() << "Mapping landing pad: " << BB->getName() << "\n");
-
- if (NumClauses == 0) {
- findCleanupHandlers(Actions, BB, nullptr);
- return;
- }
-
- VisitedBlockSet VisitedBlocks;
-
- while (HandlersFound != NumClauses) {
- BasicBlock *NextBB = nullptr;
-
- // Skip over filter clauses.
- if (LPad->isFilter(HandlersFound)) {
- ++HandlersFound;
- continue;
- }
-
- // See if the clause we're looking for is a catch-all.
- // If so, the catch begins immediately.
- Constant *ExpectedSelector =
- LPad->getClause(HandlersFound)->stripPointerCasts();
- if (isa<ConstantPointerNull>(ExpectedSelector)) {
- // The catch all must occur last.
- assert(HandlersFound == NumClauses - 1);
-
- // There can be additional selector dispatches in the call chain that we
- // need to ignore.
- BasicBlock *CatchBlock = nullptr;
- Constant *Selector;
- while (BB && isSelectorDispatch(BB, CatchBlock, Selector, NextBB)) {
- DEBUG(dbgs() << " Found extra catch dispatch in block "
- << CatchBlock->getName() << "\n");
- BB = NextBB;
- }
-
- // Add the catch handler to the action list.
- CatchHandler *Action = nullptr;
- if (CatchHandlerMap.count(BB) && CatchHandlerMap[BB] != nullptr) {
- // If the CatchHandlerMap already has an entry for this BB, re-use it.
- Action = CatchHandlerMap[BB];
- assert(Action->getSelector() == ExpectedSelector);
- } else {
- // We don't expect a selector dispatch, but there may be a call to
- // llvm.eh.begincatch, which separates catch handling code from
- // cleanup code in the same control flow. This call looks for the
- // begincatch intrinsic.
- Action = findCatchHandler(BB, NextBB, VisitedBlocks);
- if (Action) {
- // For C++ EH, check if there is any interesting cleanup code before
- // we begin the catch. This is important because cleanups cannot
- // rethrow exceptions but code called from catches can. For SEH, it
- // isn't important if some finally code before a catch-all is executed
- // out of line or after recovering from the exception.
- if (Personality == EHPersonality::MSVC_CXX)
- findCleanupHandlers(Actions, BB, BB);
- } else {
- // If an action was not found, it means that the control flows
- // directly into the catch-all handler and there is no cleanup code.
- // That's an expected situation and we must create a catch action.
- // Since this is a catch-all handler, the selector won't actually
- // appear in the code anywhere. ExpectedSelector here is the constant
- // null ptr that we got from the landing pad instruction.
- Action = new CatchHandler(BB, ExpectedSelector, nullptr);
- CatchHandlerMap[BB] = Action;
- }
- }
- Actions.insertCatchHandler(Action);
- DEBUG(dbgs() << " Catch all handler at block " << BB->getName() << "\n");
- ++HandlersFound;
-
- // Once we reach a catch-all, don't expect to hit a resume instruction.
- BB = nullptr;
- break;
- }
-
- CatchHandler *CatchAction = findCatchHandler(BB, NextBB, VisitedBlocks);
- assert(CatchAction);
-
- // See if there is any interesting code executed before the dispatch.
- findCleanupHandlers(Actions, BB, CatchAction->getStartBlock());
-
- // When the source program contains multiple nested try blocks the catch
- // handlers can get strung together in such a way that we can encounter
- // a dispatch for a selector that we've already had a handler for.
- if (CatchAction->getSelector()->stripPointerCasts() == ExpectedSelector) {
- ++HandlersFound;
-
- // Add the catch handler to the action list.
- DEBUG(dbgs() << " Found catch dispatch in block "
- << CatchAction->getStartBlock()->getName() << "\n");
- Actions.insertCatchHandler(CatchAction);
- } else {
- // 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
- // 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>(
- CatchAction->getSelector()->stripPointerCasts())) {
- DEBUG(dbgs() << " Applying early catch-all handler in block "
- << CatchAction->getStartBlock()->getName()
- << " to all remaining clauses.\n");
- Actions.insertCatchHandler(CatchAction);
- return;
- }
-
- DEBUG(dbgs() << " Found extra catch dispatch in block "
- << CatchAction->getStartBlock()->getName() << "\n");
- }
-
- // Move on to the block after the catch handler.
- BB = NextBB;
- }
-
- // If we didn't wind up in a catch-all, see if there is any interesting code
- // executed before the resume.
- findCleanupHandlers(Actions, BB, BB);
-
- // It's possible that some optimization moved code into a landingpad that
- // wasn't
- // previously being used for cleanup. If that happens, we need to execute
- // that
- // extra code from a cleanup handler.
- if (Actions.includesCleanup() && !LPad->isCleanup())
- LPad->setCleanup(true);
-}
-
-// This function searches starting with the input block for the next
-// block that terminates with a branch whose condition is based on a selector
-// comparison. This may be the input block. See the mapLandingPadBlocks
-// comments for a discussion of control flow assumptions.
-//
-CatchHandler *WinEHPrepare::findCatchHandler(BasicBlock *BB,
- BasicBlock *&NextBB,
- VisitedBlockSet &VisitedBlocks) {
- // See if we've already found a catch handler use it.
- // Call count() first to avoid creating a null entry for blocks
- // we haven't seen before.
- if (CatchHandlerMap.count(BB) && CatchHandlerMap[BB] != nullptr) {
- CatchHandler *Action = cast<CatchHandler>(CatchHandlerMap[BB]);
- NextBB = Action->getNextBB();
- return Action;
- }
-
- // VisitedBlocks applies only to the current search. We still
- // need to consider blocks that we've visited while mapping other
- // landing pads.
- VisitedBlocks.insert(BB);
-
- BasicBlock *CatchBlock = nullptr;
- Constant *Selector = nullptr;
-
- // If this is the first time we've visited this block from any landing pad
- // look to see if it is a selector dispatch block.
- if (!CatchHandlerMap.count(BB)) {
- if (isSelectorDispatch(BB, CatchBlock, Selector, NextBB)) {
- CatchHandler *Action = new CatchHandler(BB, Selector, NextBB);
- CatchHandlerMap[BB] = Action;
- return Action;
- }
- // If we encounter a block containing an llvm.eh.begincatch before we
- // find a selector dispatch block, the handler is assumed to be
- // reached unconditionally. This happens for catch-all blocks, but
- // it can also happen for other catch handlers that have been combined
- // with the catch-all handler during optimization.
- if (isCatchBlock(BB)) {
- PointerType *Int8PtrTy = Type::getInt8PtrTy(BB->getContext());
- Constant *NullSelector = ConstantPointerNull::get(Int8PtrTy);
- CatchHandler *Action = new CatchHandler(BB, NullSelector, nullptr);
- CatchHandlerMap[BB] = Action;
- return Action;
- }
- }
-
- // Visit each successor, looking for the dispatch.
- // FIXME: We expect to find the dispatch quickly, so this will probably
- // work better as a breadth first search.
- for (BasicBlock *Succ : successors(BB)) {
- if (VisitedBlocks.count(Succ))
- continue;
-
- CatchHandler *Action = findCatchHandler(Succ, NextBB, VisitedBlocks);
- if (Action)
- return Action;
- }
- return nullptr;
-}
-
-// These are helper functions to combine repeated code from findCleanupHandlers.
-static void createCleanupHandler(LandingPadActions &Actions,
- CleanupHandlerMapTy &CleanupHandlerMap,
- BasicBlock *BB) {
- CleanupHandler *Action = new CleanupHandler(BB);
- CleanupHandlerMap[BB] = Action;
- Actions.insertCleanupHandler(Action);
- DEBUG(dbgs() << " Found cleanup code in block "
- << Action->getStartBlock()->getName() << "\n");
-}
-
-static CallSite matchOutlinedFinallyCall(BasicBlock *BB,
- Instruction *MaybeCall) {
- // Look for finally blocks that Clang has already outlined for us.
- // %fp = call i8* @llvm.localaddress()
- // call void @"fin$parent"(iN 1, i8* %fp)
- 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 (!isLocalAddressCall(FinallyCall.getArgument(1)))
- return CallSite();
- return FinallyCall;
-}
-
-static BasicBlock *followSingleUnconditionalBranches(BasicBlock *BB) {
- // Skip single ubr blocks.
- while (BB->getFirstNonPHIOrDbg() == BB->getTerminator()) {
- auto *Br = dyn_cast<BranchInst>(BB->getTerminator());
- if (Br && Br->isUnconditional())
- BB = Br->getSuccessor(0);
- else
- return BB;
- }
- return BB;
-}
-
-// This function searches starting with the input block for the next block that
-// contains code that is not part of a catch handler and would not be eliminated
-// during handler outlining.
-//
-void WinEHPrepare::findCleanupHandlers(LandingPadActions &Actions,
- BasicBlock *StartBB, BasicBlock *EndBB) {
- // Here we will skip over the following:
- //
- // landing pad prolog:
- //
- // Unconditional branches
- //
- // Selector dispatch
- //
- // Resume pattern
- //
- // Anything else marks the start of an interesting block
-
- BasicBlock *BB = StartBB;
- // Anything other than an unconditional branch will kick us out of this loop
- // one way or another.
- while (BB) {
- BB = followSingleUnconditionalBranches(BB);
- // If we've already scanned this block, don't scan it again. If it is
- // a cleanup block, there will be an action in the CleanupHandlerMap.
- // If we've scanned it and it is not a cleanup block, there will be a
- // nullptr in the CleanupHandlerMap. If we have not scanned it, there will
- // be no entry in the CleanupHandlerMap. We must call count() first to
- // avoid creating a null entry for blocks we haven't scanned.
- if (CleanupHandlerMap.count(BB)) {
- if (auto *Action = CleanupHandlerMap[BB]) {
- Actions.insertCleanupHandler(Action);
- DEBUG(dbgs() << " Found cleanup code in block "
- << Action->getStartBlock()->getName() << "\n");
- // FIXME: This cleanup might chain into another, and we need to discover
- // that.
- return;
- } else {
- // Here we handle the case where the cleanup handler map contains a
- // 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 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
- // branch is the only case for which we might need to continue
- // searching.
- BasicBlock *SuccBB = followSingleUnconditionalBranches(BB);
- if (SuccBB == BB || SuccBB == EndBB)
- return;
- BB = SuccBB;
- continue;
- }
- }
-
- // Create an entry in the cleanup handler map for this block. Initially
- // we create an entry that says this isn't a cleanup block. If we find
- // cleanup code, the caller will replace this entry.
- CleanupHandlerMap[BB] = nullptr;
-
- TerminatorInst *Terminator = BB->getTerminator();
-
- // Landing pad blocks have extra instructions we need to accept.
- LandingPadMap *LPadMap = nullptr;
- if (BB->isLandingPad()) {
- LandingPadInst *LPad = BB->getLandingPadInst();
- LPadMap = &LPadMaps[LPad];
- if (!LPadMap->isInitialized())
- LPadMap->mapLandingPad(LPad);
- }
-
- // Look for the bare resume pattern:
- // %lpad.val1 = insertvalue { i8*, i32 } undef, i8* %exn, 0
- // %lpad.val2 = insertvalue { i8*, i32 } %lpad.val1, i32 %sel, 1
- // resume { i8*, i32 } %lpad.val2
- if (auto *Resume = dyn_cast<ResumeInst>(Terminator)) {
- InsertValueInst *Insert1 = nullptr;
- InsertValueInst *Insert2 = nullptr;
- Value *ResumeVal = Resume->getOperand(0);
- // If the resume value isn't a phi or landingpad value, it should be a
- // series of insertions. Identify them so we can avoid them when scanning
- // for cleanups.
- if (!isa<PHINode>(ResumeVal) && !isa<LandingPadInst>(ResumeVal)) {
- Insert2 = dyn_cast<InsertValueInst>(ResumeVal);
- if (!Insert2)
- return createCleanupHandler(Actions, CleanupHandlerMap, BB);
- Insert1 = dyn_cast<InsertValueInst>(Insert2->getAggregateOperand());
- if (!Insert1)
- return createCleanupHandler(Actions, CleanupHandlerMap, BB);
- }
- for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
- II != IE; ++II) {
- Instruction *Inst = II;
- if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
- continue;
- if (Inst == Insert1 || Inst == Insert2 || Inst == Resume)
- continue;
- if (!Inst->hasOneUse() ||
- (Inst->user_back() != Insert1 && Inst->user_back() != Insert2)) {
- return createCleanupHandler(Actions, CleanupHandlerMap, BB);
- }
- }
- return;
- }
-
- BranchInst *Branch = dyn_cast<BranchInst>(Terminator);
- if (Branch && Branch->isConditional()) {
- // Look for the selector dispatch.
- // %2 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIf to i8*))
- // %matches = icmp eq i32 %sel, %2
- // br i1 %matches, label %catch14, label %eh.resume
- CmpInst *Compare = dyn_cast<CmpInst>(Branch->getCondition());
- if (!Compare || !Compare->isEquality())
- return createCleanupHandler(Actions, CleanupHandlerMap, BB);
- for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
- II != IE; ++II) {
- Instruction *Inst = II;
- if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
- continue;
- if (Inst == Compare || Inst == Branch)
- continue;
- if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>()))
- continue;
- return createCleanupHandler(Actions, CleanupHandlerMap, BB);
- }
- // The selector dispatch block should always terminate our search.
- assert(BB == EndBB);
- return;
- }
-
- if (isAsynchronousEHPersonality(Personality)) {
- // If this is a landingpad block, split the block at the first non-landing
- // pad instruction.
- Instruction *MaybeCall = BB->getFirstNonPHIOrDbg();
- if (LPadMap) {
- while (MaybeCall != BB->getTerminator() &&
- LPadMap->isLandingPadSpecificInst(MaybeCall))
- MaybeCall = MaybeCall->getNextNode();
- }
-
- // 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 =
- SplitBlock(BB, FinallyCall.getInstruction()->getNextNode(), DT);
- } else {
- 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;
- }
- }
- }
-
- // Anything else is either a catch block or interesting cleanup code.
- for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
- II != IE; ++II) {
- Instruction *Inst = II;
- if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
- continue;
- // Unconditional branches fall through to this loop.
- if (Inst == Branch)
- continue;
- // If this is a catch block, there is no cleanup code to be found.
- if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>()))
- return;
- // If this a nested landing pad, it may contain an endcatch call.
- if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>()))
- return;
- // Anything else makes this interesting cleanup code.
- return createCleanupHandler(Actions, CleanupHandlerMap, BB);
- }
-
- // Only unconditional branches in empty blocks should get this far.
- assert(Branch && Branch->isUnconditional());
- if (BB == EndBB)
- return;
- BB = Branch->getSuccessor(0);
- }
-}
-
-// This is a public function, declared in WinEHFuncInfo.h and is also
-// referenced by WinEHNumbering in FunctionLoweringInfo.cpp.
-void llvm::parseEHActions(
- const IntrinsicInst *II,
- SmallVectorImpl<std::unique_ptr<ActionHandler>> &Actions) {
- assert(II->getIntrinsicID() == Intrinsic::eh_actions &&
- "attempted to parse non eh.actions intrinsic");
- for (unsigned I = 0, E = II->getNumArgOperands(); I != E;) {
- uint64_t ActionKind =
- cast<ConstantInt>(II->getArgOperand(I))->getZExtValue();
- if (ActionKind == /*catch=*/1) {
- auto *Selector = cast<Constant>(II->getArgOperand(I + 1));
- ConstantInt *EHObjIndex = cast<ConstantInt>(II->getArgOperand(I + 2));
- int64_t EHObjIndexVal = EHObjIndex->getSExtValue();
- Constant *Handler = cast<Constant>(II->getArgOperand(I + 3));
- I += 4;
- auto CH = make_unique<CatchHandler>(/*BB=*/nullptr, Selector,
- /*NextBB=*/nullptr);
- CH->setHandlerBlockOrFunc(Handler);
- CH->setExceptionVarIndex(EHObjIndexVal);
- Actions.push_back(std::move(CH));
- } else if (ActionKind == 0) {
- Constant *Handler = cast<Constant>(II->getArgOperand(I + 1));
- I += 2;
- auto CH = make_unique<CleanupHandler>(/*BB=*/nullptr);
- CH->setHandlerBlockOrFunc(Handler);
- Actions.push_back(std::move(CH));
- } else {
- llvm_unreachable("Expected either a catch or cleanup handler!");
- }
- }
- std::reverse(Actions.begin(), Actions.end());
-}
-
-namespace {
-struct WinEHNumbering {
- WinEHNumbering(WinEHFuncInfo &FuncInfo) : FuncInfo(FuncInfo),
- CurrentBaseState(-1), NextState(0) {}
-
- WinEHFuncInfo &FuncInfo;
- int CurrentBaseState;
- int NextState;
-
- SmallVector<std::unique_ptr<ActionHandler>, 4> HandlerStack;
- SmallPtrSet<const Function *, 4> VisitedHandlers;
-
- int currentEHNumber() const {
- return HandlerStack.empty() ? CurrentBaseState : HandlerStack.back()->getEHState();
- }
+ // 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(Fn);
- 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);
-};
+ SmallVector<BasicBlock *, 4> EntryBlocks;
+ findFuncletEntryPoints(Fn, EntryBlocks);
+ return prepareExplicitEH(Fn, EntryBlocks);
}
+bool WinEHPrepare::doFinalization(Module &M) { return false; }
+
+void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const {}
+
static int addUnwindMapEntry(WinEHFuncInfo &FuncInfo, int ToState,
- const Value *V) {
- WinEHUnwindMapEntry UME;
+ const BasicBlock *BB) {
+ CxxUnwindMapEntry UME;
UME.ToState = ToState;
- UME.Cleanup = V;
- FuncInfo.UnwindMap.push_back(UME);
+ UME.Cleanup = BB;
+ FuncInfo.CxxUnwindMap.push_back(UME);
return FuncInfo.getLastStateNumber();
}
for (const CatchPadInst *CPI : Handlers) {
WinEHHandlerType HT;
Constant *TypeInfo = cast<Constant>(CPI->getArgOperand(0));
- if (TypeInfo->isNullValue()) {
- HT.Adjectives = 0x40;
- HT.TypeDescriptor = nullptr;
- } else {
- auto *GV = cast<GlobalVariable>(TypeInfo->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());
- }
- HT.Handler = CPI->getNormalDest();
- HT.HandlerMBB = nullptr;
- // FIXME: Pass CPI->getArgOperand(1).
- HT.CatchObjRecoverIdx = -1;
- TBME.HandlerArray.push_back(HT);
- }
- FuncInfo.TryBlockMap.push_back(TBME);
-}
-
-void WinEHNumbering::createUnwindMapEntry(int ToState, ActionHandler *AH) {
- Value *V = nullptr;
- if (auto *CH = dyn_cast_or_null<CleanupHandler>(AH))
- V = cast<Function>(CH->getHandlerBlockOrFunc());
- addUnwindMapEntry(FuncInfo, ToState, V);
-}
-
-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)
- 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;
- }
- }
-
- // 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);
- return;
- }
-
- // 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;
+ if (TypeInfo->isNullValue())
HT.TypeDescriptor = nullptr;
- } 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());
- }
- HT.Handler = cast<Function>(CH->getHandlerBlockOrFunc());
- HT.HandlerMBB = nullptr;
- HT.CatchObjRecoverIdx = CH->getExceptionVarIndex();
+ else
+ HT.TypeDescriptor = cast<GlobalVariable>(TypeInfo->stripPointerCasts());
+ HT.Adjectives = cast<ConstantInt>(CPI->getArgOperand(1))->getZExtValue();
+ HT.Handler = CPI->getParent();
+ 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 void print_name(const Value *V) {
-#ifndef NDEBUG
- if (!V) {
- DEBUG(dbgs() << "null");
- return;
- }
-
- if (const auto *F = dyn_cast<Function>(V))
- DEBUG(dbgs() << F->getName());
- else
- DEBUG(V->dump());
-#endif
-}
-
-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;
- }
-
- // 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]);
- continue;
- }
- 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++;
- }
- HandlerStack.push_back(std::move(Actions[I]));
- LastActionWasCatch = CurrActionIsCatch;
- LastRootLPad = RootLPad;
- }
-
- // 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()))
- continue;
- FuncInfo.LastInvokeVisited[Handler] = true;
- DEBUG(dbgs() << "Last invoke of ");
- print_name(Handler);
- DEBUG(dbgs() << " has been visited.\n");
- }
- }
-
- 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;
- }
- }
-
- 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);
- }
- else {
- DEBUG(dbgs() << "Deferring handling of ");
- print_name(F);
- DEBUG(dbgs() << " until last invoke visited.\n");
- }
- }
- 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.
-
- int OldBaseState = CurrentBaseState;
- if (FuncInfo.HandlerBaseState.count(&F)) {
- CurrentBaseState = FuncInfo.HandlerBaseState[&F];
- }
-
- size_t SavedHandlerStackSize = HandlerStack.size();
-
- 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);
- }
- 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.EHPadStateMap[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);
-
- DEBUG(dbgs() << "Assigning max state " << NextState - 1
- << " to " << F.getName() << '\n');
- FuncInfo.CatchHandlerMaxState[&F] = NextState - 1;
-
- CurrentBaseState = OldBaseState;
-}
-
-// 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.
-
- 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;
-
- assert(ActionsCall->getIntrinsicID() == Intrinsic::eh_actions);
- parseEHActions(ActionsCall, ActionList);
- if (ActionList.empty())
- 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)
- continue;
- DEBUG(dbgs() << "Setting root lpad for ");
- print_name(Handler);
- DEBUG(dbgs() << " to " << LPI->getParent()->getName() << '\n');
- FuncInfo.RootLPad[Handler] = LPI;
- }
- }
- // 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();
- }
+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;
}
-static const BasicBlock *getSingleCatchPadPredecessor(const BasicBlock &BB) {
- for (const BasicBlock *PredBlock : predecessors(&BB))
- if (isa<CatchPadInst>(PredBlock->getFirstNonPHI()))
- return PredBlock;
- 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());
}
// Given BB which ends in an unwind edge, return the EHPad that this BB belongs
const TerminatorInst *TI = BB->getTerminator();
if (isa<InvokeInst>(TI))
return nullptr;
- if (isa<CatchPadInst>(TI) || isa<CatchEndPadInst>(TI) ||
- isa<TerminatePadInst>(TI))
+ if (TI->isEHPad())
return BB;
- if (auto *CEPI = dyn_cast<CleanupEndPadInst>(TI))
- return CEPI->getCleanupPad()->getParent();
return cast<CleanupReturnInst>(TI)->getCleanupPad()->getParent();
}
-static void calculateExplicitStateNumbers(WinEHFuncInfo &FuncInfo,
- const BasicBlock &BB,
- int ParentState) {
+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
return;
if (isa<CatchEndPadInst>(FirstNonPHI)) {
- const BasicBlock *TryPad = &BB;
- const BasicBlock *LastTryPad = nullptr;
SmallVector<const CatchPadInst *, 2> Handlers;
- do {
- LastTryPad = TryPad;
- TryPad = getSingleCatchPadPredecessor(*TryPad);
- if (TryPad)
- Handlers.push_back(cast<CatchPadInst>(TryPad->getFirstNonPHI()));
- } while (TryPad);
- // 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());
+ 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(LastTryPad))
+ for (const BasicBlock *PredBlock : predecessors(FirstTryPad))
if ((PredBlock = getEHPadFromPredecessor(PredBlock)))
- calculateExplicitStateNumbers(FuncInfo, *PredBlock, TryLow);
+ 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)))
- calculateExplicitStateNumbers(FuncInfo, *PredBlock, CatchLow);
+ calculateExplicitCXXStateNumbers(FuncInfo, *PredBlock, CatchLow);
int CatchHigh = FuncInfo.getLastStateNumber();
addTryBlockMapEntry(FuncInfo, TryLow, TryHigh, CatchHigh, Handlers);
- DEBUG(dbgs() << "TryLow[" << LastTryPad->getName() << "]: " << TryLow
+ DEBUG(dbgs() << "TryLow[" << FirstTryPad->getName() << "]: " << TryLow
<< '\n');
- DEBUG(dbgs() << "TryHigh[" << LastTryPad->getName() << "]: " << TryHigh
+ DEBUG(dbgs() << "TryHigh[" << FirstTryPad->getName() << "]: " << TryHigh
<< '\n');
- DEBUG(dbgs() << "CatchHigh[" << LastTryPad->getName() << "]: " << CatchHigh
+ DEBUG(dbgs() << "CatchHigh[" << FirstTryPad->getName() << "]: " << CatchHigh
<< '\n');
} else if (isa<CleanupPadInst>(FirstNonPHI)) {
+ // A cleanup can have multiple exits; don't re-process after the first.
+ if (FuncInfo.EHPadStateMap.count(FirstNonPHI))
+ return;
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)))
- calculateExplicitStateNumbers(FuncInfo, *PredBlock, CleanupState);
+ calculateExplicitCXXStateNumbers(FuncInfo, *PredBlock, CleanupState);
+ } else if (auto *CEPI = dyn_cast<CleanupEndPadInst>(FirstNonPHI)) {
+ // Propagate ParentState to the cleanuppad in case it doesn't have
+ // any cleanuprets.
+ BasicBlock *CleanupBlock = CEPI->getCleanupPad()->getParent();
+ calculateExplicitCXXStateNumbers(FuncInfo, *CleanupBlock, ParentState);
+ // Anything unwinding through CleanupEndPadInst is in ParentState.
+ FuncInfo.EHPadStateMap[FirstNonPHI] = ParentState;
+ for (const BasicBlock *PredBlock : predecessors(&BB))
+ if ((PredBlock = getEHPadFromPredecessor(PredBlock)))
+ calculateExplicitCXXStateNumbers(FuncInfo, *PredBlock, ParentState);
+ } else if (isa<TerminatePadInst>(FirstNonPHI)) {
+ report_fatal_error("Not yet implemented!");
+ } else {
+ llvm_unreachable("unexpected EH Pad!");
+ }
+}
+
+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;
+}
+
+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, CatchPadBB);
+
+ // 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)) {
+ // A cleanup can have multiple exits; don't re-process after the first.
+ if (FuncInfo.EHPadStateMap.count(FirstNonPHI))
+ return;
+ 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 (auto *CEPI = dyn_cast<CleanupEndPadInst>(FirstNonPHI)) {
+ // Propagate ParentState to the cleanuppad in case it doesn't have
+ // any cleanuprets.
+ BasicBlock *CleanupBlock = CEPI->getCleanupPad()->getParent();
+ calculateExplicitSEHStateNumbers(FuncInfo, *CleanupBlock, ParentState);
+ // 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 {
}
}
-void llvm::calculateWinCXXEHStateNumbers(const Function *ParentFn,
+/// 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;
+ calculateExplicitSEHStateNumbers(FuncInfo, BB, -1);
+ }
+}
+
+void llvm::calculateWinCXXEHStateNumbers(const Function *Fn,
WinEHFuncInfo &FuncInfo) {
// Return if it's already been done.
if (!FuncInfo.EHPadStateMap.empty())
return;
- bool IsExplicit = false;
- for (const BasicBlock &BB : *ParentFn) {
+ 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))
+ if (!doesEHPadUnwindToCaller(FirstNonPHI))
continue;
- // Check if the EH Pad has no exceptional successors (i.e. it unwinds to
- // caller). Cleanups are a little bit of a special case because their
- // control flow cannot be determined by looking at the pad but instead by
- // the pad's users.
- bool HasNoSuccessors = false;
- if (FirstNonPHI->mayThrow()) {
- HasNoSuccessors = true;
- } else if (auto *CPI = dyn_cast<CleanupPadInst>(FirstNonPHI)) {
- if (CPI->use_empty()) {
- HasNoSuccessors = true;
- } else {
- const Instruction *User = CPI->user_back();
- if (auto *CRI = dyn_cast<CleanupReturnInst>(User))
- HasNoSuccessors = CRI->unwindsToCaller();
- else
- HasNoSuccessors = cast<CleanupEndPadInst>(User)->unwindsToCaller();
- }
- }
+ calculateExplicitCXXStateNumbers(FuncInfo, BB, -1);
+ }
+}
+
+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;
- if (!HasNoSuccessors)
+ // 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;
- calculateExplicitStateNumbers(FuncInfo, BB, -1);
- IsExplicit = true;
+ // 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 *PadBlock = Catch->getParent();
+ uint32_t TypeToken = static_cast<uint32_t>(
+ cast<ConstantInt>(Catch->getArgOperand(0))->getZExtValue());
+ int NewState = addClrEHHandler(FuncInfo, ParentState,
+ ClrHandlerType::Catch, TypeToken, PadBlock);
+ FuncInfo.EHPadStateMap[Catch] = NewState;
+ // Preds of the catch get its state
+ PredState = NewState;
+ } else {
+ 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);
+ }
}
+}
- if (IsExplicit)
+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);
- 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());
+ // 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();
+ }
}
-void WinEHPrepare::colorFunclets(Function &F,
- SmallVectorImpl<BasicBlock *> &EntryBlocks) {
+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();
!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});
- }
+ // Queue exits (i.e. successors of rets/endpads) with the parent color.
+ // Skip any exits that are catchendpads, since the parent color must then
+ // represent one of the catches chained to that catchendpad, but the
+ // catchendpad should get the color of the common parent of all its
+ // chained catches (i.e. the grandparent color of the current pad).
+ // We don't need to worry abou catchendpads going unvisited, since the
+ // catches chained to them must have unwind edges to them by which we will
+ // visit them.
+ for (User *U : VisitingHead->users()) {
+ if (auto *Exit = dyn_cast<TerminatorInst>(U)) {
+ for (BasicBlock *Succ : successors(Exit->getParent()))
+ if (!isa<CatchEndPadInst>(*Succ->getFirstNonPHI()))
+ if (BlockColors[Succ].insert(Color).second)
+ Worklist.push_back({Succ, Color});
}
}
// Handle CatchPad specially since its successors need different colors.
} 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 block's successors have already been queued with the parent
- // color.
- continue;
- }
+ }
+
+ 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())) {
}
}
-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);
+void WinEHPrepare::colorFunclets(Function &F,
+ SmallVectorImpl<BasicBlock *> &EntryBlocks) {
+ ::colorFunclets(F, EntryBlocks, BlockColors, FuncletBlocks, FuncletChildren);
+}
- // Determine which blocks are reachable from which funclet entries.
- colorFunclets(F, EntryBlocks);
+void llvm::calculateCatchReturnSuccessorColors(const Function *Fn,
+ WinEHFuncInfo &FuncInfo) {
+ SmallVector<BasicBlock *, 4> EntryBlocks;
+ // colorFunclets needs the set of EntryBlocks, get them using
+ // findFuncletEntryPoints.
+ findFuncletEntryPoints(const_cast<Function &>(*Fn), EntryBlocks);
+
+ 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 = dyn_cast<CatchReturnInst>(Exit);
+ if (!CatchReturn)
+ continue;
+ BasicBlock *CatchRetSuccessor = CatchReturn->getSuccessor();
+ std::set<BasicBlock *> &SuccessorColors = BlockColors[CatchRetSuccessor];
+ assert(SuccessorColors.size() == 1 && "Expected BB to be monochrome!");
+ BasicBlock *Color = *SuccessorColors.begin();
+ // Record the catchret successor's funclet membership.
+ FuncInfo.CatchRetSuccessorColorMap[CatchReturn] = Color;
+ }
+ }
+}
+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++;
+ BasicBlock *BB = &*FI++;
if (!BB->isEHPad())
continue;
for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) {
- Instruction *I = BI++;
+ Instruction *I = &*BI++;
auto *PN = dyn_cast<PHINode>(I);
// Stop at the first non-PHI.
if (!PN)
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++;
+ BasicBlock *BB = &*FI++;
std::set<BasicBlock *> &ColorsForBB = BlockColors[BB];
for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) {
- Instruction *I = BI++;
+ Instruction *I = &*BI++;
// Funclets are permitted to use static allocas.
if (auto *AI = dyn_cast<AllocaInst>(I))
if (AI->isStaticAlloca())
demoteNonlocalUses(I, ColorsForBB, F);
}
}
+}
+
+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);
+}
+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.
Orig2Clone[BB] = CBB;
}
+ // If nothing was cloned, we're done cloning in this funclet.
+ if (Orig2Clone.empty())
+ continue;
+
// Update our color mappings to reflect that one block has lost a color and
// another has gained a color.
for (auto &BBMapping : Orig2Clone) {
BlockColors[OldBlock].erase(FuncletPadBB);
}
- // Loop over all of the instructions in the function, fixing up operand
+ // Loop over all of the instructions in this funclet, 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);
+ RemapInstruction(&I, VMap,
+ RF_IgnoreMissingEntries | RF_NoModuleLevelChanges);
+
+ // 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);
+ }
+ }
+ }
+
+ 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());
+ }
}
+}
+void WinEHPrepare::removeImplausibleTerminators(Function &F) {
// Remove implausible terminators and replace them with UnreachableInst.
for (auto &Funclet : FuncletBlocks) {
BasicBlock *FuncletPadBB = Funclet.first;
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);
+ }
+ }
+
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).
}
}
+}
+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++;
+ BasicBlock *BB = &*FI++;
SimplifyInstructionsInBlock(BB);
ConstantFoldTerminator(BB, /*DeleteDeadConditions=*/true);
MergeBlockIntoPredecessor(BB);
// 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();
report_fatal_error("Uncolored BB!");
if (NumColors > 1)
report_fatal_error("Multicolor BB!");
- 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!");
+ 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!");
+ }
+ }
+}
+
+bool WinEHPrepare::prepareExplicitEH(
+ Function &F, SmallVectorImpl<BasicBlock *> &EntryBlocks) {
+ replaceTerminatePadWithCleanup(F);
+
+ // Determine which blocks are reachable from which funclet entries.
+ colorFunclets(F, EntryBlocks);
+
+ if (!DisableDemotion) {
+ demotePHIsOnFunclets(F);
+
+ demoteUsesBetweenFunclets(F);
+
+ demoteArgumentUses(F);
+ }
+
+ cloneCommonBlocks(F, EntryBlocks);
+
+ if (!DisableCleanups) {
+ removeImplausibleTerminators(F);
+
+ cleanupPreparedFunclets(F);
}
+ verifyPreparedFunclets(F);
+
BlockColors.clear();
FuncletBlocks.clear();
FuncletChildren.clear();
// 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());
+ &F.getEntryBlock().front());
Value *V = new LoadInst(SpillSlot, Twine(PN->getName(), ".wineh.reload"),
- PHIBlock->getFirstInsertionPt());
+ &*PHIBlock->getFirstInsertionPt());
PN->replaceAllUsesWith(V);
return SpillSlot;
}
// because we can't insert the store AFTER the terminator instruction.
BasicBlock::iterator InsertPt;
if (isa<Argument>(V)) {
- InsertPt = F.getEntryBlock().getTerminator();
+ InsertPt = F.getEntryBlock().getTerminator()->getIterator();
} else if (isa<TerminatorInst>(V)) {
auto *II = cast<InvokeInst>(V);
// We cannot demote invoke instructions to the stack if their normal
}
InsertPt = II->getNormalDest()->getFirstInsertionPt();
} else {
- InsertPt = cast<Instruction>(V);
+ InsertPt = cast<Instruction>(V)->getIterator();
++InsertPt;
// Don't insert before PHI nodes or EH pad instrs.
for (; isa<PHINode>(InsertPt) || InsertPt->isEHPad(); ++InsertPt)
;
}
- new StoreInst(V, SpillSlot, InsertPt);
+ new StoreInst(V, SpillSlot, &*InsertPt);
}
}
if (!SpillSlot)
SpillSlot = new AllocaInst(V->getType(), nullptr,
Twine(V->getName(), ".wineh.spillslot"),
- F.getEntryBlock().begin());
+ &F.getEntryBlock().front());
auto *UsingInst = cast<Instruction>(U.getUser());
if (auto *UsingPHI = dyn_cast<PHINode>(UsingInst)) {
U.set(Load);
}
}
+
+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);
+}
projects / oota-llvm.git / blobdiff