[WinEH] Generate .xdata for catch handlers
This lets us catch exceptions in simple cases.
N.B. Things that do not work include (but are not limited to):
- Throwing from within a catch handler.
- Catching an object with a named catch parameter.
- 'CatchHigh' is fictitious, we aren't sure of its purpose.
- We aren't entirely efficient with regards to the number of EH states
that we generate.
- IP-to-State tables are sensitive to the order of emission.
llvm-svn: 233767
diff --git a/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp b/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp
index 974e94d..7a82daa 100644
--- a/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp
@@ -68,6 +68,27 @@
shouldEmitLSDA = shouldEmitPersonality &&
LSDAEncoding != dwarf::DW_EH_PE_omit;
+
+ // If this was an outlined handler, we need to define the label corresponding
+ // to the offset of the parent frame relative to the stack pointer after the
+ // prologue.
+ const Function *F = MF->getFunction();
+ const Function *ParentF = MMI->getWinEHParent(F);
+ if (F != ParentF) {
+ WinEHFuncInfo &FuncInfo = MMI->getWinEHFuncInfo(ParentF);
+ auto I = FuncInfo.CatchHandlerParentFrameObjOffset.find(F);
+ if (I != FuncInfo.CatchHandlerParentFrameObjOffset.end()) {
+ MCSymbol *HandlerTypeParentFrameOffset =
+ Asm->OutContext.getOrCreateParentFrameOffsetSymbol(
+ GlobalValue::getRealLinkageName(F->getName()));
+
+ // Emit a symbol assignment.
+ Asm->OutStreamer.EmitAssignment(
+ HandlerTypeParentFrameOffset,
+ MCConstantExpr::Create(I->second, Asm->OutContext));
+ }
+ }
+
if (!shouldEmitPersonality && !shouldEmitMoves)
return;
@@ -253,6 +274,7 @@
const Function *F = MF->getFunction();
const Function *ParentF = MMI->getWinEHParent(F);
auto &OS = Asm->OutStreamer;
+ WinEHFuncInfo &FuncInfo = MMI->getWinEHFuncInfo(ParentF);
StringRef ParentLinkageName =
GlobalValue::getRealLinkageName(ParentF->getName());
@@ -279,8 +301,6 @@
// an ordinary call) between the end of the previous try-range and now.
bool SawPotentiallyThrowing = false;
- WinEHFuncInfo &FuncInfo = MMI->getWinEHFuncInfo(ParentF);
-
int LastEHState = -2;
// The parent function and the catch handlers contribute to the 'ip2state'
@@ -424,11 +444,17 @@
// };
OS.EmitLabel(HandlerMapXData);
for (const WinEHHandlerType &HT : TBME.HandlerArray) {
+ MCSymbol *ParentFrameOffset =
+ Asm->OutContext.getOrCreateParentFrameOffsetSymbol(
+ GlobalValue::getRealLinkageName(HT.Handler->getName()));
+ const MCSymbolRefExpr *ParentFrameOffsetRef = MCSymbolRefExpr::Create(
+ ParentFrameOffset, MCSymbolRefExpr::VK_None, Asm->OutContext);
+
OS.EmitIntValue(HT.Adjectives, 4); // Adjectives
OS.EmitValue(createImageRel32(HT.TypeDescriptor), 4); // Type
- OS.EmitIntValue(0, 4); // CatchObjOffset
+ OS.EmitIntValue(HT.CatchObjOffset, 4); // CatchObjOffset
OS.EmitValue(createImageRel32(HT.Handler), 4); // Handler
- OS.EmitIntValue(0, 4); // ParentFrameOffset
+ OS.EmitValue(ParentFrameOffsetRef, 4); // ParentFrameOffset
}
}
}
diff --git a/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp b/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
index c00b118..e2235fb 100644
--- a/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
@@ -88,6 +88,7 @@
int NextState;
SmallVector<ActionHandler *, 4> HandlerStack;
+ SmallPtrSet<const Function *, 4> VisitedHandlers;
int currentEHNumber() const {
return HandlerStack.empty() ? -1 : HandlerStack.back()->getEHState();
@@ -96,7 +97,9 @@
void parseEHActions(const IntrinsicInst *II,
SmallVectorImpl<ActionHandler *> &Actions);
void createUnwindMapEntry(int ToState, ActionHandler *AH);
- void proccessCallSite(ArrayRef<ActionHandler *> Actions, ImmutableCallSite CS);
+ void createTryBlockMapEntry(int TryLow, int TryHigh,
+ ArrayRef<CatchHandler *> Handlers);
+ void processCallSite(ArrayRef<ActionHandler *> Actions, ImmutableCallSite CS);
void calculateStateNumbers(const Function &F);
};
}
@@ -276,8 +279,12 @@
MBBMap[Invoke->getSuccessor(1)]->setIsLandingPad();
// Calculate EH numbers for WinEH.
- if (fn.getFnAttribute("wineh-parent").getValueAsString() == fn.getName())
- WinEHNumbering(MMI.getWinEHFuncInfo(&fn)).calculateStateNumbers(fn);
+ if (fn.getFnAttribute("wineh-parent").getValueAsString() == fn.getName()) {
+ WinEHNumbering Num(MMI.getWinEHFuncInfo(&fn));
+ Num.calculateStateNumbers(fn);
+ // Pop everything on the handler stack.
+ Num.processCallSite(None, ImmutableCallSite());
+ }
}
void WinEHNumbering::parseEHActions(const IntrinsicInst *II,
@@ -309,13 +316,42 @@
void WinEHNumbering::createUnwindMapEntry(int ToState, ActionHandler *AH) {
WinEHUnwindMapEntry UME;
UME.ToState = ToState;
- if (auto *CH = dyn_cast<CleanupHandler>(AH))
+ if (auto *CH = dyn_cast_or_null<CleanupHandler>(AH))
UME.Cleanup = cast<Function>(CH->getHandlerBlockOrFunc());
else
UME.Cleanup = nullptr;
FuncInfo.UnwindMap.push_back(UME);
}
+void WinEHNumbering::createTryBlockMapEntry(int TryLow, int TryHigh,
+ ArrayRef<CatchHandler *> Handlers) {
+ WinEHTryBlockMapEntry TBME;
+ TBME.TryLow = TryLow;
+ TBME.TryHigh = TryHigh;
+ // FIXME: This should be revisited when we want to throw inside a catch
+ // handler.
+ TBME.CatchHigh = INT_MAX;
+ assert(TBME.TryLow <= TBME.TryHigh);
+ assert(TBME.CatchHigh > TBME.TryHigh);
+ for (CatchHandler *CH : Handlers) {
+ WinEHHandlerType HT;
+ 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());
+ // FIXME: We don't support catching objects yet!
+ HT.CatchObjIdx = INT_MAX;
+ HT.CatchObjOffset = 0;
+ TBME.HandlerArray.push_back(HT);
+ }
+ FuncInfo.TryBlockMap.push_back(TBME);
+}
+
static void print_name(const Value *V) {
#ifndef NDEBUG
if (!V) {
@@ -330,10 +366,8 @@
#endif
}
-void WinEHNumbering::proccessCallSite(ArrayRef<ActionHandler *> Actions,
- ImmutableCallSite CS) {
- // float, int
- // float, double, int
+void WinEHNumbering::processCallSite(ArrayRef<ActionHandler *> Actions,
+ ImmutableCallSite CS) {
int FirstMismatch = 0;
for (int E = std::min(HandlerStack.size(), Actions.size()); FirstMismatch < E;
++FirstMismatch) {
@@ -343,28 +377,65 @@
delete Actions[FirstMismatch];
}
+ bool EnteringScope = (int)Actions.size() > FirstMismatch;
+ bool ExitingScope = (int)HandlerStack.size() > 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<const Function *, 4> UnnumberedHandlers;
+ SmallVector<CatchHandler *, 4> PoppedCatches;
for (int I = HandlerStack.size() - 1; I >= FirstMismatch; --I) {
- if (auto *CH = dyn_cast<CatchHandler>(HandlerStack.back()))
- if (const auto *F = dyn_cast<Function>(CH->getHandlerBlockOrFunc()))
- UnnumberedHandlers.push_back(F);
- // Pop the handlers off of the stack.
- delete HandlerStack.back();
+ if (auto *CH = dyn_cast<CatchHandler>(HandlerStack.back())) {
+ PoppedCatches.push_back(CH);
+ } else {
+ // Delete cleanup handlers
+ delete HandlerStack.back();
+ }
HandlerStack.pop_back();
}
- for (const Function *F : UnnumberedHandlers)
- calculateStateNumbers(*F);
+ // We need to create a new state number if we are exiting a try scope and we
+ // will not push any more actions.
+ int TryHigh = NextState - 1;
+ if (ExitingScope && !EnteringScope && !PoppedCatches.empty()) {
+ createUnwindMapEntry(currentEHNumber(), nullptr);
+ ++NextState;
+ }
+ int LastTryLowIdx = 0;
+ for (int I = 0, E = PoppedCatches.size(); I != E; ++I) {
+ CatchHandler *CH = PoppedCatches[I];
+ if (I + 1 == E || CH->getEHState() != PoppedCatches[I + 1]->getEHState()) {
+ int TryLow = CH->getEHState();
+ auto Handlers =
+ makeArrayRef(&PoppedCatches[LastTryLowIdx], I - LastTryLowIdx + 1);
+ createTryBlockMapEntry(TryLow, TryHigh, Handlers);
+ LastTryLowIdx = I + 1;
+ }
+ }
+
+ for (CatchHandler *CH : PoppedCatches) {
+ if (auto *F = dyn_cast<Function>(CH->getHandlerBlockOrFunc()))
+ calculateStateNumbers(*F);
+ delete CH;
+ }
+
+ bool LastActionWasCatch = false;
for (size_t I = FirstMismatch; I != Actions.size(); ++I) {
- createUnwindMapEntry(currentEHNumber(), Actions[I]);
- Actions[I]->setEHState(NextState++);
- DEBUG(dbgs() << "Creating unwind map entry for: (");
- print_name(Actions[I]->getHandlerBlockOrFunc());
- DEBUG(dbgs() << ", " << currentEHNumber() << ")\n");
+ // We can reuse eh states when pushing two catches for the same invoke.
+ bool CurrActionIsCatch = isa<CatchHandler>(Actions[I]);
+ // FIXME: Reenable this optimization!
+ if (CurrActionIsCatch && LastActionWasCatch && false) {
+ Actions[I]->setEHState(currentEHNumber());
+ } else {
+ createUnwindMapEntry(currentEHNumber(), Actions[I]);
+ Actions[I]->setEHState(NextState);
+ NextState++;
+ DEBUG(dbgs() << "Creating unwind map entry for: (");
+ print_name(Actions[I]->getHandlerBlockOrFunc());
+ DEBUG(dbgs() << ", " << currentEHNumber() << ")\n");
+ }
HandlerStack.push_back(Actions[I]);
+ LastActionWasCatch = CurrActionIsCatch;
}
DEBUG(dbgs() << "In EHState " << currentEHNumber() << " for CallSite: ");
@@ -373,6 +444,10 @@
}
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.
+
DEBUG(dbgs() << "Calculating state numbers for: " << F.getName() << '\n');
SmallVector<ActionHandler *, 4> ActionList;
for (const BasicBlock &BB : F) {
@@ -380,21 +455,21 @@
const auto *CI = dyn_cast<CallInst>(&I);
if (!CI || CI->doesNotThrow())
continue;
- proccessCallSite(None, CI);
+ processCallSite(None, CI);
}
const auto *II = dyn_cast<InvokeInst>(BB.getTerminator());
if (!II)
continue;
const LandingPadInst *LPI = II->getLandingPadInst();
- if (auto *ActionsCall = dyn_cast<IntrinsicInst>(LPI->getNextNode())) {
- assert(ActionsCall->getIntrinsicID() == Intrinsic::eh_actions);
- parseEHActions(ActionsCall, ActionList);
- proccessCallSite(ActionList, II);
- ActionList.clear();
- FuncInfo.LandingPadStateMap[LPI] = currentEHNumber();
- }
+ auto *ActionsCall = dyn_cast<IntrinsicInst>(LPI->getNextNode());
+ if (!ActionsCall)
+ continue;
+ assert(ActionsCall->getIntrinsicID() == Intrinsic::eh_actions);
+ parseEHActions(ActionsCall, ActionList);
+ processCallSite(ActionList, II);
+ ActionList.clear();
+ FuncInfo.LandingPadStateMap[LPI] = currentEHNumber();
}
- proccessCallSite(None, ImmutableCallSite());
}
/// clear - Clear out all the function-specific state. This returns this
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index fd9d7e6..fa58614 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -5450,18 +5450,6 @@
case Intrinsic::eh_begincatch:
case Intrinsic::eh_endcatch:
llvm_unreachable("begin/end catch intrinsics not lowered in codegen");
- case Intrinsic::eh_parentframe: {
- AllocaInst *Slot =
- cast<AllocaInst>(I.getArgOperand(0)->stripPointerCasts());
- assert(FuncInfo.StaticAllocaMap.count(Slot) &&
- "can only use static allocas with llvm.eh.parentframe");
- int FI = FuncInfo.StaticAllocaMap[Slot];
- MachineFunction &MF = DAG.getMachineFunction();
- const Function *F = MF.getFunction();
- MachineModuleInfo &MMI = MF.getMMI();
- MMI.getWinEHFuncInfo(F).CatchHandlerParentFrameObjIdx[F] = FI;
- return nullptr;
- }
case Intrinsic::eh_unwindhelp: {
AllocaInst *Slot =
cast<AllocaInst>(I.getArgOperand(0)->stripPointerCasts());
diff --git a/llvm/lib/CodeGen/WinEHPrepare.cpp b/llvm/lib/CodeGen/WinEHPrepare.cpp
index 94e046c..5b4ee17 100644
--- a/llvm/lib/CodeGen/WinEHPrepare.cpp
+++ b/llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -638,16 +638,6 @@
if (!LPadMap.isInitialized())
LPadMap.mapLandingPad(LPad);
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
- // Insert an alloca for the object which holds the address of the parent's
- // frame pointer. The stack offset of this object needs to be encoded in
- // xdata.
- AllocaInst *ParentFrame = new AllocaInst(Int8PtrType, "parentframe", Entry);
- Builder.CreateStore(&Handler->getArgumentList().back(), ParentFrame,
- /*isStore=*/true);
- Function *ParentFrameFn =
- Intrinsic::getDeclaration(M, Intrinsic::eh_parentframe);
- Builder.CreateCall(ParentFrameFn, ParentFrame);
-
Constant *Sel = CatchAction->getSelector();
Director.reset(new WinEHCatchDirector(Handler, Sel, VarInfo, LPadMap));
LPadMap.remapSelector(VMap, ConstantInt::get(Type::getInt32Ty(Context), 1));