[WinEH] Start EH preparation for 32-bit x86, it uses no arguments
32-bit x86 MSVC-style exceptions are functionaly similar to 64-bit, but
they take no arguments. Instead, they implicitly use the value of EBP
passed in by the caller as a pointer to the parent's frame. In LLVM, we
can represent this as llvm.frameaddress(1), and feed that into all of
our calls to llvm.framerecover.
The next steps are:
- Add an alloca to the fs:00 linked list of handlers
- Add something like llvm.sjlj.lsda or generalize it to store in the
alloca
- Move state number calculation to WinEHPrepare, arrange for
FunctionLoweringInfo to call it
- Use the state numbers to insert explicit loads and stores in the IR
llvm-svn: 236172
diff --git a/llvm/lib/CodeGen/WinEHPrepare.cpp b/llvm/lib/CodeGen/WinEHPrepare.cpp
index 0fa5a12..0461d71 100644
--- a/llvm/lib/CodeGen/WinEHPrepare.cpp
+++ b/llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -19,6 +19,7 @@
#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/LibCallSemantics.h"
#include "llvm/CodeGen/WinEHFuncInfo.h"
@@ -71,7 +72,10 @@
public:
static char ID; // Pass identification, replacement for typeid.
WinEHPrepare(const TargetMachine *TM = nullptr)
- : FunctionPass(ID), DT(nullptr), SEHExceptionCodeSlot(nullptr) {}
+ : FunctionPass(ID), DT(nullptr), SEHExceptionCodeSlot(nullptr) {
+ if (TM)
+ TheTriple = Triple(TM->getTargetTriple());
+ }
bool runOnFunction(Function &Fn) override;
@@ -97,6 +101,8 @@
LandingPadInst *OutlinedLPad,
const LandingPadInst *OriginalLPad,
FrameVarInfoMap &VarInfo);
+ Function *createHandlerFunc(Type *RetTy, const Twine &Name, Module *M,
+ Value *&ParentFP);
bool outlineHandler(ActionHandler *Action, Function *SrcFn,
LandingPadInst *LPad, BasicBlock *StartBB,
FrameVarInfoMap &VarInfo);
@@ -110,6 +116,8 @@
void processSEHCatchHandler(CatchHandler *Handler, BasicBlock *StartBB);
+ Triple TheTriple;
+
// All fields are reset by runOnFunction.
DominatorTree *DT;
EHPersonality Personality;
@@ -138,12 +146,16 @@
// outlined but before the outlined code is pruned from the parent function.
DenseMap<const BasicBlock *, BasicBlock *> LPadTargetBlocks;
+ // Map from outlined handler to call to llvm.frameaddress(1). Only used for
+ // 32-bit EH.
+ DenseMap<Function *, Value *> HandlerToParentFP;
+
AllocaInst *SEHExceptionCodeSlot;
};
class WinEHFrameVariableMaterializer : public ValueMaterializer {
public:
- WinEHFrameVariableMaterializer(Function *OutlinedFn,
+ WinEHFrameVariableMaterializer(Function *OutlinedFn, Value *ParentFP,
FrameVarInfoMap &FrameVarInfo);
~WinEHFrameVariableMaterializer() override {}
@@ -179,16 +191,12 @@
class WinEHCloningDirectorBase : public CloningDirector {
public:
- WinEHCloningDirectorBase(Function *HandlerFn, FrameVarInfoMap &VarInfo,
- LandingPadMap &LPadMap)
- : Materializer(HandlerFn, VarInfo),
+ 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) {
- auto AI = HandlerFn->getArgumentList().begin();
- ++AI;
- EstablisherFrame = AI;
- }
+ LPadMap(LPadMap), ParentFP(ParentFP) {}
CloningAction handleInstruction(ValueToValueMapTy &VMap,
const Instruction *Inst,
@@ -225,16 +233,16 @@
LandingPadMap &LPadMap;
/// The value representing the parent frame pointer.
- Value *EstablisherFrame;
+ Value *ParentFP;
};
class WinEHCatchDirector : public WinEHCloningDirectorBase {
public:
WinEHCatchDirector(
- Function *CatchFn, Value *Selector, FrameVarInfoMap &VarInfo,
- LandingPadMap &LPadMap,
+ Function *CatchFn, Value *ParentFP, Value *Selector,
+ FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap,
DenseMap<LandingPadInst *, const LandingPadInst *> &NestedLPads)
- : WinEHCloningDirectorBase(CatchFn, VarInfo, LPadMap),
+ : WinEHCloningDirectorBase(CatchFn, ParentFP, VarInfo, LPadMap),
CurrentSelector(Selector->stripPointerCasts()),
ExceptionObjectVar(nullptr), NestedLPtoOriginalLP(NestedLPads) {}
@@ -272,9 +280,10 @@
class WinEHCleanupDirector : public WinEHCloningDirectorBase {
public:
- WinEHCleanupDirector(Function *CleanupFn, FrameVarInfoMap &VarInfo,
- LandingPadMap &LPadMap)
- : WinEHCloningDirectorBase(CleanupFn, VarInfo, LPadMap) {}
+ WinEHCleanupDirector(Function *CleanupFn, Value *ParentFP,
+ FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap)
+ : WinEHCloningDirectorBase(CleanupFn, ParentFP, VarInfo,
+ LPadMap) {}
CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
const Instruction *Inst,
@@ -880,19 +889,23 @@
if (TempAlloca == getCatchObjectSentinel())
continue; // Skip catch parameter sentinels.
Function *HandlerFn = TempAlloca->getParent()->getParent();
- // FIXME: Sink this GEP into the blocks where it is used.
+ llvm::Value *FP = HandlerToParentFP[HandlerFn];
+ assert(FP);
+
+ // FIXME: Sink this framerecover into the blocks where it is used.
Builder.SetInsertPoint(TempAlloca);
Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc());
Value *RecoverArgs[] = {
- Builder.CreateBitCast(&F, Int8PtrType, ""),
- &(HandlerFn->getArgumentList().back()),
+ Builder.CreateBitCast(&F, Int8PtrType, ""), FP,
llvm::ConstantInt::get(Int32Type, AllocasToEscape.size() - 1)};
- Value *RecoveredAlloca = Builder.CreateCall(RecoverFrameFn, RecoverArgs);
+ 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 =
- Builder.CreateBitCast(RecoveredAlloca, TempAlloca->getType());
+ RecoveredAlloca = cast<Instruction>(
+ Builder.CreateBitCast(RecoveredAlloca, TempAlloca->getType()));
}
TempAlloca->replaceAllUsesWith(RecoveredAlloca);
TempAlloca->removeFromParent();
@@ -918,6 +931,8 @@
CatchHandlerMap.clear();
DeleteContainerSeconds(CleanupHandlerMap);
CleanupHandlerMap.clear();
+ HandlerToParentFP.clear();
+ DT = nullptr;
return HandlersOutlined;
}
@@ -987,7 +1002,6 @@
IntrinsicInst *EHActions = cast<IntrinsicInst>(Recover->clone());
// Remap the exception variables into the outlined function.
- WinEHFrameVariableMaterializer Materializer(OutlinedHandlerFn, FrameVarInfo);
SmallVector<BlockAddress *, 4> ActionTargets;
SmallVector<ActionHandler *, 4> ActionList;
parseEHActions(EHActions, ActionList);
@@ -1148,35 +1162,62 @@
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(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();
+ FunctionType *FnType;
+ if (TheTriple.getArch() == Triple::x86_64) {
+ Type *Int8PtrType = Type::getInt8PtrTy(Context);
+ Type *ArgTys[2] = {Int8PtrType, Int8PtrType};
+ FnType = FunctionType::get(RetTy, ArgTys, false);
+ } else {
+ 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);
+ Value *Args[1] = {ConstantInt::get(Type::getInt32Ty(Context), 1)};
+ ParentFP = CallInst::Create(FrameAddressFn, Args, "parent_fp",
+ &Handler->getEntryBlock());
+ }
+ 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.
- Type *Int8PtrType = Type::getInt8PtrTy(Context);
- std::vector<Type *> ArgTys;
- ArgTys.push_back(Int8PtrType);
- ArgTys.push_back(Int8PtrType);
+ Value *ParentFP;
Function *Handler;
if (Action->getType() == Catch) {
- FunctionType *FnType = FunctionType::get(Int8PtrType, ArgTys, false);
- Handler = Function::Create(FnType, GlobalVariable::InternalLinkage,
- SrcFn->getName() + ".catch", M);
+ Handler = createHandlerFunc(Int8PtrType, SrcFn->getName() + ".catch", M,
+ ParentFP);
} else {
- FunctionType *FnType =
- FunctionType::get(Type::getVoidTy(Context), ArgTys, false);
- Handler = Function::Create(FnType, GlobalVariable::InternalLinkage,
- SrcFn->getName() + ".cleanup", M);
+ Handler = createHandlerFunc(Type::getVoidTy(Context),
+ SrcFn->getName() + ".cleanup", M, ParentFP);
}
-
+ 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);
- BasicBlock *Entry = BasicBlock::Create(Context, "entry");
- Handler->getBasicBlockList().push_front(Entry);
Builder.SetInsertPoint(Entry);
Builder.SetCurrentDebugLocation(LPad->getDebugLoc());
@@ -1189,12 +1230,14 @@
LPadMap.mapLandingPad(LPad);
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
Constant *Sel = CatchAction->getSelector();
- Director.reset(new WinEHCatchDirector(Handler, Sel, VarInfo, LPadMap,
+ Director.reset(new WinEHCatchDirector(Handler, ParentFP, Sel,
+ VarInfo, LPadMap,
NestedLPtoOriginalLP));
LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType),
ConstantInt::get(Type::getInt32Ty(Context), 1));
} else {
- Director.reset(new WinEHCleanupDirector(Handler, VarInfo, LPadMap));
+ Director.reset(
+ new WinEHCleanupDirector(Handler, ParentFP, VarInfo, LPadMap));
LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType),
UndefValue::get(Type::getInt32Ty(Context)));
}
@@ -1421,7 +1464,7 @@
// When outlining llvm.frameaddress(i32 0), remap that to the second argument,
// which is the FP of the parent.
if (isFrameAddressCall(Inst)) {
- VMap[Inst] = EstablisherFrame;
+ VMap[Inst] = ParentFP;
return CloningDirector::SkipInstruction;
}
@@ -1660,10 +1703,16 @@
}
WinEHFrameVariableMaterializer::WinEHFrameVariableMaterializer(
- Function *OutlinedFn, FrameVarInfoMap &FrameVarInfo)
+ Function *OutlinedFn, Value *ParentFP, FrameVarInfoMap &FrameVarInfo)
: FrameVarInfo(FrameVarInfo), Builder(OutlinedFn->getContext()) {
BasicBlock *EntryBB = &OutlinedFn->getEntryBlock();
- Builder.SetInsertPoint(EntryBB, EntryBB->getFirstInsertionPt());
+
+ // 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) {
