-//===- SjLjEHPass.cpp - Eliminate Invoke & Unwind instructions -----------===//
+//===- SjLjEHPrepare.cpp - Eliminate Invoke & Unwind instructions ---------===//
//
// The LLVM Compiler Infrastructure
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "sjljehprepare"
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/Constants.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Instructions.h"
-#include "llvm/Intrinsics.h"
-#include "llvm/LLVMContext.h"
-#include "llvm/Module.h"
-#include "llvm/Pass.h"
#include "llvm/CodeGen/Passes.h"
-#include "llvm/Target/TargetLowering.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Support/Debug.h"
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetLowering.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/Local.h"
#include <set>
using namespace llvm;
STATISTIC(NumInvokes, "Number of invokes replaced");
-STATISTIC(NumUnwinds, "Number of unwinds replaced");
STATISTIC(NumSpilled, "Number of registers live across unwind edges");
namespace {
- class SjLjEHPass : public FunctionPass {
+ class SjLjEHPrepare : public FunctionPass {
const TargetLowering *TLI;
Type *FunctionContextTy;
Constant *RegisterFn;
Constant *StackRestoreFn;
Constant *LSDAAddrFn;
Value *PersonalityFn;
- Constant *SelectorFn;
- Constant *ExceptionFn;
Constant *CallSiteFn;
- Constant *DispatchSetupFn;
- Value *CallSite;
- DenseMap<InvokeInst*, BasicBlock*> LPadSuccMap;
+ Constant *FuncCtxFn;
+ AllocaInst *FuncCtx;
public:
static char ID; // Pass identification, replacement for typeid
- explicit SjLjEHPass(const TargetLowering *tli = NULL)
+ explicit SjLjEHPrepare(const TargetLowering *tli = NULL)
: FunctionPass(ID), TLI(tli) { }
bool doInitialization(Module &M);
bool runOnFunction(Function &F);
}
private:
- void insertCallSiteStore(Instruction *I, int Number, Value *CallSite);
- void markInvokeCallSite(InvokeInst *II, int InvokeNo, Value *CallSite,
- SwitchInst *CatchSwitch);
- void splitLiveRangesAcrossInvokes(SmallVector<InvokeInst*,16> &Invokes);
- bool insertSjLjEHSupport(Function &F);
+ bool setupEntryBlockAndCallSites(Function &F);
+ void substituteLPadValues(LandingPadInst *LPI, Value *ExnVal,
+ Value *SelVal);
+ Value *setupFunctionContext(Function &F, ArrayRef<LandingPadInst*> LPads);
+ void lowerIncomingArguments(Function &F);
+ void lowerAcrossUnwindEdges(Function &F, ArrayRef<InvokeInst*> Invokes);
+ void insertCallSiteStore(Instruction *I, int Number);
};
} // end anonymous namespace
-char SjLjEHPass::ID = 0;
+char SjLjEHPrepare::ID = 0;
-// Public Interface To the SjLjEHPass pass.
-FunctionPass *llvm::createSjLjEHPass(const TargetLowering *TLI) {
- return new SjLjEHPass(TLI);
+// Public Interface To the SjLjEHPrepare pass.
+FunctionPass *llvm::createSjLjEHPreparePass(const TargetLowering *TLI) {
+ return new SjLjEHPrepare(TLI);
}
// doInitialization - Set up decalarations and types needed to process
// exceptions.
-bool SjLjEHPass::doInitialization(Module &M) {
+bool SjLjEHPrepare::doInitialization(Module &M) {
// Build the function context structure.
// builtin_setjmp uses a five word jbuf
Type *VoidPtrTy = Type::getInt8PtrTy(M.getContext());
StackRestoreFn = Intrinsic::getDeclaration(&M, Intrinsic::stackrestore);
BuiltinSetjmpFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_setjmp);
LSDAAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_lsda);
- SelectorFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_selector);
- ExceptionFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_exception);
CallSiteFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_callsite);
- DispatchSetupFn
- = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_dispatch_setup);
+ FuncCtxFn = Intrinsic::getDeclaration(&M, Intrinsic::eh_sjlj_functioncontext);
PersonalityFn = 0;
return true;
/// insertCallSiteStore - Insert a store of the call-site value to the
/// function context
-void SjLjEHPass::insertCallSiteStore(Instruction *I, int Number,
- Value *CallSite) {
+void SjLjEHPrepare::insertCallSiteStore(Instruction *I, int Number) {
+ IRBuilder<> Builder(I);
+
+ // Get a reference to the call_site field.
+ Type *Int32Ty = Type::getInt32Ty(I->getContext());
+ Value *Zero = ConstantInt::get(Int32Ty, 0);
+ Value *One = ConstantInt::get(Int32Ty, 1);
+ Value *Idxs[2] = { Zero, One };
+ Value *CallSite = Builder.CreateGEP(FuncCtx, Idxs, "call_site");
+
+ // Insert a store of the call-site number
ConstantInt *CallSiteNoC = ConstantInt::get(Type::getInt32Ty(I->getContext()),
Number);
- // Insert a store of the call-site number
- new StoreInst(CallSiteNoC, CallSite, true, I); // volatile
+ Builder.CreateStore(CallSiteNoC, CallSite, true/*volatile*/);
}
-/// markInvokeCallSite - Insert code to mark the call_site for this invoke
-void SjLjEHPass::markInvokeCallSite(InvokeInst *II, int InvokeNo,
- Value *CallSite,
- SwitchInst *CatchSwitch) {
- ConstantInt *CallSiteNoC= ConstantInt::get(Type::getInt32Ty(II->getContext()),
- InvokeNo);
- // The runtime comes back to the dispatcher with the call_site - 1 in
- // the context. Odd, but there it is.
- ConstantInt *SwitchValC = ConstantInt::get(Type::getInt32Ty(II->getContext()),
- InvokeNo - 1);
-
- // If the unwind edge has phi nodes, split the edge.
- if (isa<PHINode>(II->getUnwindDest()->begin())) {
- SplitCriticalEdge(II, 1, this);
-
- // If there are any phi nodes left, they must have a single predecessor.
- while (PHINode *PN = dyn_cast<PHINode>(II->getUnwindDest()->begin())) {
- PN->replaceAllUsesWith(PN->getIncomingValue(0));
- PN->eraseFromParent();
- }
- }
-
- // Insert the store of the call site value
- insertCallSiteStore(II, InvokeNo, CallSite);
+/// MarkBlocksLiveIn - Insert BB and all of its predescessors into LiveBBs until
+/// we reach blocks we've already seen.
+static void MarkBlocksLiveIn(BasicBlock *BB,
+ SmallPtrSet<BasicBlock*, 64> &LiveBBs) {
+ if (!LiveBBs.insert(BB)) return; // already been here.
- // Record the call site value for the back end so it stays associated with
- // the invoke.
- CallInst::Create(CallSiteFn, CallSiteNoC, "", II);
+ for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
+ MarkBlocksLiveIn(*PI, LiveBBs);
+}
- // Add a switch case to our unwind block.
- if (BasicBlock *SuccBB = LPadSuccMap[II]) {
- CatchSwitch->addCase(SwitchValC, SuccBB);
- } else {
- CatchSwitch->addCase(SwitchValC, II->getUnwindDest());
+/// substituteLPadValues - Substitute the values returned by the landingpad
+/// instruction with those returned by the personality function.
+void SjLjEHPrepare::substituteLPadValues(LandingPadInst *LPI, Value *ExnVal,
+ Value *SelVal) {
+ SmallVector<Value*, 8> UseWorkList(LPI->use_begin(), LPI->use_end());
+ while (!UseWorkList.empty()) {
+ Value *Val = UseWorkList.pop_back_val();
+ ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(Val);
+ if (!EVI) continue;
+ if (EVI->getNumIndices() != 1) continue;
+ if (*EVI->idx_begin() == 0)
+ EVI->replaceAllUsesWith(ExnVal);
+ else if (*EVI->idx_begin() == 1)
+ EVI->replaceAllUsesWith(SelVal);
+ if (EVI->getNumUses() == 0)
+ EVI->eraseFromParent();
}
- // We still want this to look like an invoke so we emit the LSDA properly,
- // so we don't transform the invoke into a call here.
-}
+ if (LPI->getNumUses() == 0) return;
-/// MarkBlocksLiveIn - Insert BB and all of its predescessors into LiveBBs until
-/// we reach blocks we've already seen.
-static void MarkBlocksLiveIn(BasicBlock *BB, std::set<BasicBlock*> &LiveBBs) {
- if (!LiveBBs.insert(BB).second) return; // already been here.
+ // There are still some uses of LPI. Construct an aggregate with the exception
+ // values and replace the LPI with that aggregate.
+ Type *LPadType = LPI->getType();
+ Value *LPadVal = UndefValue::get(LPadType);
+ IRBuilder<>
+ Builder(llvm::next(BasicBlock::iterator(cast<Instruction>(SelVal))));
+ LPadVal = Builder.CreateInsertValue(LPadVal, ExnVal, 0, "lpad.val");
+ LPadVal = Builder.CreateInsertValue(LPadVal, SelVal, 1, "lpad.val");
- for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
- MarkBlocksLiveIn(*PI, LiveBBs);
+ LPI->replaceAllUsesWith(LPadVal);
}
-/// splitLiveRangesAcrossInvokes - Each value that is live across an unwind edge
-/// we spill into a stack location, guaranteeing that there is nothing live
-/// across the unwind edge. This process also splits all critical edges
-/// coming out of invoke's.
-/// FIXME: Move this function to a common utility file (Local.cpp?) so
-/// both SjLj and LowerInvoke can use it.
-void SjLjEHPass::
-splitLiveRangesAcrossInvokes(SmallVector<InvokeInst*,16> &Invokes) {
- // First step, split all critical edges from invoke instructions.
- for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
- InvokeInst *II = Invokes[i];
- SplitCriticalEdge(II, 0, this);
-
- // FIXME: New EH - This if-condition will be always true in the new scheme.
- if (II->getUnwindDest()->isLandingPad()) {
- SmallVector<BasicBlock*, 2> NewBBs;
- SplitLandingPadPredecessors(II->getUnwindDest(), II->getParent(),
- ".1", ".2", this, NewBBs);
- LPadSuccMap[II] = *succ_begin(NewBBs[0]);
- } else {
- SplitCriticalEdge(II, 1, this);
- }
+/// setupFunctionContext - Allocate the function context on the stack and fill
+/// it with all of the data that we know at this point.
+Value *SjLjEHPrepare::
+setupFunctionContext(Function &F, ArrayRef<LandingPadInst*> LPads) {
+ BasicBlock *EntryBB = F.begin();
- assert(!isa<PHINode>(II->getNormalDest()) &&
- !isa<PHINode>(II->getUnwindDest()) &&
- "Critical edge splitting left single entry phi nodes?");
+ // Create an alloca for the incoming jump buffer ptr and the new jump buffer
+ // that needs to be restored on all exits from the function. This is an alloca
+ // because the value needs to be added to the global context list.
+ unsigned Align =
+ TLI->getDataLayout()->getPrefTypeAlignment(FunctionContextTy);
+ FuncCtx =
+ new AllocaInst(FunctionContextTy, 0, Align, "fn_context", EntryBB->begin());
+
+ // Fill in the function context structure.
+ for (unsigned I = 0, E = LPads.size(); I != E; ++I) {
+ LandingPadInst *LPI = LPads[I];
+ IRBuilder<> Builder(LPI->getParent()->getFirstInsertionPt());
+
+ // Reference the __data field.
+ Value *FCData = Builder.CreateConstGEP2_32(FuncCtx, 0, 2, "__data");
+
+ // The exception values come back in context->__data[0].
+ Value *ExceptionAddr = Builder.CreateConstGEP2_32(FCData, 0, 0,
+ "exception_gep");
+ Value *ExnVal = Builder.CreateLoad(ExceptionAddr, true, "exn_val");
+ ExnVal = Builder.CreateIntToPtr(ExnVal, Builder.getInt8PtrTy());
+
+ Value *SelectorAddr = Builder.CreateConstGEP2_32(FCData, 0, 1,
+ "exn_selector_gep");
+ Value *SelVal = Builder.CreateLoad(SelectorAddr, true, "exn_selector_val");
+
+ substituteLPadValues(LPI, ExnVal, SelVal);
}
- Function *F = Invokes.back()->getParent()->getParent();
-
- // To avoid having to handle incoming arguments specially, we lower each arg
- // to a copy instruction in the entry block. This ensures that the argument
- // value itself cannot be live across the entry block.
- BasicBlock::iterator AfterAllocaInsertPt = F->begin()->begin();
- while (isa<AllocaInst>(AfterAllocaInsertPt) &&
- isa<ConstantInt>(cast<AllocaInst>(AfterAllocaInsertPt)->getArraySize()))
- ++AfterAllocaInsertPt;
- for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
- AI != E; ++AI) {
+ // Personality function
+ IRBuilder<> Builder(EntryBB->getTerminator());
+ if (!PersonalityFn)
+ PersonalityFn = LPads[0]->getPersonalityFn();
+ Value *PersonalityFieldPtr = Builder.CreateConstGEP2_32(FuncCtx, 0, 3,
+ "pers_fn_gep");
+ Builder.CreateStore(PersonalityFn, PersonalityFieldPtr, /*isVolatile=*/true);
+
+ // LSDA address
+ Value *LSDA = Builder.CreateCall(LSDAAddrFn, "lsda_addr");
+ Value *LSDAFieldPtr = Builder.CreateConstGEP2_32(FuncCtx, 0, 4, "lsda_gep");
+ Builder.CreateStore(LSDA, LSDAFieldPtr, /*isVolatile=*/true);
+
+ return FuncCtx;
+}
+
+/// lowerIncomingArguments - To avoid having to handle incoming arguments
+/// specially, we lower each arg to a copy instruction in the entry block. This
+/// ensures that the argument value itself cannot be live out of the entry
+/// block.
+void SjLjEHPrepare::lowerIncomingArguments(Function &F) {
+ BasicBlock::iterator AfterAllocaInsPt = F.begin()->begin();
+ while (isa<AllocaInst>(AfterAllocaInsPt) &&
+ isa<ConstantInt>(cast<AllocaInst>(AfterAllocaInsPt)->getArraySize()))
+ ++AfterAllocaInsPt;
+
+ for (Function::arg_iterator
+ AI = F.arg_begin(), AE = F.arg_end(); AI != AE; ++AI) {
Type *Ty = AI->getType();
+
// Aggregate types can't be cast, but are legal argument types, so we have
// to handle them differently. We use an extract/insert pair as a
// lightweight method to achieve the same goal.
if (isa<StructType>(Ty) || isa<ArrayType>(Ty) || isa<VectorType>(Ty)) {
- Instruction *EI = ExtractValueInst::Create(AI, 0, "",AfterAllocaInsertPt);
+ Instruction *EI = ExtractValueInst::Create(AI, 0, "", AfterAllocaInsPt);
Instruction *NI = InsertValueInst::Create(AI, EI, 0);
NI->insertAfter(EI);
AI->replaceAllUsesWith(NI);
+
// Set the operand of the instructions back to the AllocaInst.
EI->setOperand(0, AI);
NI->setOperand(0, AI);
// This is always a no-op cast because we're casting AI to AI->getType()
// so src and destination types are identical. BitCast is the only
// possibility.
- CastInst *NC = new BitCastInst(
- AI, AI->getType(), AI->getName()+".tmp", AfterAllocaInsertPt);
+ CastInst *NC =
+ new BitCastInst(AI, AI->getType(), AI->getName() + ".tmp",
+ AfterAllocaInsPt);
AI->replaceAllUsesWith(NC);
+
// Set the operand of the cast instruction back to the AllocaInst.
// Normally it's forbidden to replace a CastInst's operand because it
- // could cause the opcode to reflect an illegal conversion. However,
- // we're replacing it here with the same value it was constructed with.
- // We do this because the above replaceAllUsesWith() clobbered the
- // operand, but we want this one to remain.
+ // could cause the opcode to reflect an illegal conversion. However, we're
+ // replacing it here with the same value it was constructed with. We do
+ // this because the above replaceAllUsesWith() clobbered the operand, but
+ // we want this one to remain.
NC->setOperand(0, AI);
}
}
+}
+/// lowerAcrossUnwindEdges - Find all variables which are alive across an unwind
+/// edge and spill them.
+void SjLjEHPrepare::lowerAcrossUnwindEdges(Function &F,
+ ArrayRef<InvokeInst*> Invokes) {
// Finally, scan the code looking for instructions with bad live ranges.
- for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
- for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E; ++II) {
- // Ignore obvious cases we don't have to handle. In particular, most
+ for (Function::iterator
+ BB = F.begin(), BBE = F.end(); BB != BBE; ++BB) {
+ for (BasicBlock::iterator
+ II = BB->begin(), IIE = BB->end(); II != IIE; ++II) {
+ // Ignore obvious cases we don't have to handle. In particular, most
// instructions either have no uses or only have a single use inside the
- // current block. Ignore them quickly.
+ // current block. Ignore them quickly.
Instruction *Inst = II;
if (Inst->use_empty()) continue;
if (Inst->hasOneUse() &&
// If this is an alloca in the entry block, it's not a real register
// value.
if (AllocaInst *AI = dyn_cast<AllocaInst>(Inst))
- if (isa<ConstantInt>(AI->getArraySize()) && BB == F->begin())
+ if (isa<ConstantInt>(AI->getArraySize()) && BB == F.begin())
continue;
// Avoid iterator invalidation by copying users to a temporary vector.
- SmallVector<Instruction*,16> Users;
- for (Value::use_iterator UI = Inst->use_begin(), E = Inst->use_end();
- UI != E; ++UI) {
+ SmallVector<Instruction*, 16> Users;
+ for (Value::use_iterator
+ UI = Inst->use_begin(), E = Inst->use_end(); UI != E; ++UI) {
Instruction *User = cast<Instruction>(*UI);
if (User->getParent() != BB || isa<PHINode>(User))
Users.push_back(User);
}
// Find all of the blocks that this value is live in.
- std::set<BasicBlock*> LiveBBs;
+ SmallPtrSet<BasicBlock*, 64> LiveBBs;
LiveBBs.insert(Inst->getParent());
while (!Users.empty()) {
Instruction *U = Users.back();
for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
BasicBlock *UnwindBlock = Invokes[i]->getUnwindDest();
if (UnwindBlock != BB && LiveBBs.count(UnwindBlock)) {
+ DEBUG(dbgs() << "SJLJ Spill: " << *Inst << " around "
+ << UnwindBlock->getName() << "\n");
NeedsSpill = true;
+ break;
}
}
// the value to be reloaded from the stack slot, even those that aren't
// in the unwind blocks. We should be more selective.
if (NeedsSpill) {
- ++NumSpilled;
DemoteRegToStack(*Inst, true);
+ ++NumSpilled;
}
}
-}
-
-/// CreateLandingPadLoad - Load the exception handling values and insert them
-/// into a structure.
-static Instruction *CreateLandingPadLoad(Function &F, Value *ExnAddr,
- Value *SelAddr,
- BasicBlock::iterator InsertPt) {
- Value *Exn = new LoadInst(ExnAddr, "exn", false,
- InsertPt);
- Type *Ty = Type::getInt8PtrTy(F.getContext());
- Exn = CastInst::Create(Instruction::IntToPtr, Exn, Ty, "", InsertPt);
- Value *Sel = new LoadInst(SelAddr, "sel", false, InsertPt);
-
- Ty = StructType::get(Exn->getType(), Sel->getType(), NULL);
- InsertValueInst *LPadVal = InsertValueInst::Create(llvm::UndefValue::get(Ty),
- Exn, 0,
- "lpad.val", InsertPt);
- return InsertValueInst::Create(LPadVal, Sel, 1, "lpad.val", InsertPt);
-}
-
-/// ReplaceLandingPadVal - Replace the landingpad instruction's value with a
-/// load from the stored values (via CreateLandingPadLoad). This looks through
-/// PHI nodes, and removes them if they are dead.
-static void ReplaceLandingPadVal(Function &F, Instruction *Inst, Value *ExnAddr,
- Value *SelAddr) {
- if (Inst->use_empty()) return;
-
- while (!Inst->use_empty()) {
- Instruction *I = cast<Instruction>(Inst->use_back());
-
- if (PHINode *PN = dyn_cast<PHINode>(I)) {
- ReplaceLandingPadVal(F, PN, ExnAddr, SelAddr);
- if (PN->use_empty()) PN->eraseFromParent();
- continue;
- }
+ }
- Inst->replaceAllUsesWith(CreateLandingPadLoad(F, ExnAddr, SelAddr, I));
+ // Go through the landing pads and remove any PHIs there.
+ for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
+ BasicBlock *UnwindBlock = Invokes[i]->getUnwindDest();
+ LandingPadInst *LPI = UnwindBlock->getLandingPadInst();
+
+ // Place PHIs into a set to avoid invalidating the iterator.
+ SmallPtrSet<PHINode*, 8> PHIsToDemote;
+ for (BasicBlock::iterator
+ PN = UnwindBlock->begin(); isa<PHINode>(PN); ++PN)
+ PHIsToDemote.insert(cast<PHINode>(PN));
+ if (PHIsToDemote.empty()) continue;
+
+ // Demote the PHIs to the stack.
+ for (SmallPtrSet<PHINode*, 8>::iterator
+ I = PHIsToDemote.begin(), E = PHIsToDemote.end(); I != E; ++I)
+ DemotePHIToStack(*I);
+
+ // Move the landingpad instruction back to the top of the landing pad block.
+ LPI->moveBefore(UnwindBlock->begin());
}
}
-bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
- SmallVector<ReturnInst*,16> Returns;
- SmallVector<UnwindInst*,16> Unwinds;
- SmallVector<InvokeInst*,16> Invokes;
-
- // Look through the terminators of the basic blocks to find invokes, returns
- // and unwinds.
- for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
- if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
- // Remember all return instructions in case we insert an invoke into this
- // function.
- Returns.push_back(RI);
- } else if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
+/// setupEntryBlockAndCallSites - Setup the entry block by creating and filling
+/// the function context and marking the call sites with the appropriate
+/// values. These values are used by the DWARF EH emitter.
+bool SjLjEHPrepare::setupEntryBlockAndCallSites(Function &F) {
+ SmallVector<ReturnInst*, 16> Returns;
+ SmallVector<InvokeInst*, 16> Invokes;
+ SmallSetVector<LandingPadInst*, 16> LPads;
+
+ // Look through the terminators of the basic blocks to find invokes.
+ for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
+ if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
Invokes.push_back(II);
- } else if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
- Unwinds.push_back(UI);
+ LPads.insert(II->getUnwindDest()->getLandingPadInst());
+ } else if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
+ Returns.push_back(RI);
}
- }
-
- NumInvokes += Invokes.size();
- NumUnwinds += Unwinds.size();
- // If we don't have any invokes, there's nothing to do.
if (Invokes.empty()) return false;
- // Find the eh.selector.*, eh.exception and alloca calls.
- //
- // Remember any allocas() that aren't in the entry block, as the
- // jmpbuf saved SP will need to be updated for them.
- //
- // We'll use the first eh.selector to determine the right personality
- // function to use. For SJLJ, we always use the same personality for the
- // whole function, not on a per-selector basis.
- // FIXME: That's a bit ugly. Better way?
- SmallVector<CallInst*,16> EH_Selectors;
- SmallVector<CallInst*,16> EH_Exceptions;
- SmallVector<Instruction*,16> JmpbufUpdatePoints;
-
- for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
- // Note: Skip the entry block since there's nothing there that interests
- // us. eh.selector and eh.exception shouldn't ever be there, and we
- // want to disregard any allocas that are there.
- //
- // FIXME: This is awkward. The new EH scheme won't need to skip the entry
- // block.
- if (BB == F.begin()) {
- if (InvokeInst *II = dyn_cast<InvokeInst>(F.begin()->getTerminator())) {
- // FIXME: This will be always non-NULL in the new EH.
- if (LandingPadInst *LPI = II->getUnwindDest()->getLandingPadInst())
- if (!PersonalityFn) PersonalityFn = LPI->getPersonalityFn();
- }
-
- continue;
- }
-
- for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
- if (CallInst *CI = dyn_cast<CallInst>(I)) {
- if (CI->getCalledFunction() == SelectorFn) {
- if (!PersonalityFn) PersonalityFn = CI->getArgOperand(1);
- EH_Selectors.push_back(CI);
- } else if (CI->getCalledFunction() == ExceptionFn) {
- EH_Exceptions.push_back(CI);
- } else if (CI->getCalledFunction() == StackRestoreFn) {
- JmpbufUpdatePoints.push_back(CI);
- }
- } else if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
- JmpbufUpdatePoints.push_back(AI);
- } else if (InvokeInst *II = dyn_cast<InvokeInst>(I)) {
- // FIXME: This will be always non-NULL in the new EH.
- if (LandingPadInst *LPI = II->getUnwindDest()->getLandingPadInst())
- if (!PersonalityFn) PersonalityFn = LPI->getPersonalityFn();
- }
- }
- }
-
- // If we don't have any eh.selector calls, we can't determine the personality
- // function. Without a personality function, we can't process exceptions.
- if (!PersonalityFn) return false;
-
- // We have invokes, so we need to add register/unregister calls to get this
- // function onto the global unwind stack.
- //
- // First thing we need to do is scan the whole function for values that are
- // live across unwind edges. Each value that is live across an unwind edge we
- // spill into a stack location, guaranteeing that there is nothing live across
- // the unwind edge. This process also splits all critical edges coming out of
- // invoke's.
- splitLiveRangesAcrossInvokes(Invokes);
-
-
- SmallVector<LandingPadInst*, 16> LandingPads;
- for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
- if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator()))
- // FIXME: This will be always non-NULL in the new EH.
- if (LandingPadInst *LPI = II->getUnwindDest()->getLandingPadInst())
- LandingPads.push_back(LPI);
- }
+ NumInvokes += Invokes.size();
+ lowerIncomingArguments(F);
+ lowerAcrossUnwindEdges(F, Invokes);
+ Value *FuncCtx =
+ setupFunctionContext(F, makeArrayRef(LPads.begin(), LPads.end()));
BasicBlock *EntryBB = F.begin();
- // Create an alloca for the incoming jump buffer ptr and the new jump buffer
- // that needs to be restored on all exits from the function. This is an
- // alloca because the value needs to be added to the global context list.
- unsigned Align = 4; // FIXME: Should be a TLI check?
- AllocaInst *FunctionContext =
- new AllocaInst(FunctionContextTy, 0, Align,
- "fcn_context", F.begin()->begin());
-
- Value *Idxs[2];
- Type *Int32Ty = Type::getInt32Ty(F.getContext());
- Value *Zero = ConstantInt::get(Int32Ty, 0);
- // We need to also keep around a reference to the call_site field
- Idxs[0] = Zero;
- Idxs[1] = ConstantInt::get(Int32Ty, 1);
- CallSite = GetElementPtrInst::Create(FunctionContext, Idxs, "call_site",
- EntryBB->getTerminator());
-
- // The exception selector comes back in context->data[1]
- Idxs[1] = ConstantInt::get(Int32Ty, 2);
- Value *FCData = GetElementPtrInst::Create(FunctionContext, Idxs, "fc_data",
- EntryBB->getTerminator());
- Idxs[1] = ConstantInt::get(Int32Ty, 1);
- Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs,
- "exc_selector_gep",
- EntryBB->getTerminator());
- // The exception value comes back in context->data[0]
- Idxs[1] = Zero;
- Value *ExceptionAddr = GetElementPtrInst::Create(FCData, Idxs,
- "exception_gep",
- EntryBB->getTerminator());
-
- // The result of the eh.selector call will be replaced with a a reference to
- // the selector value returned in the function context. We leave the selector
- // itself so the EH analysis later can use it.
- for (int i = 0, e = EH_Selectors.size(); i < e; ++i) {
- CallInst *I = EH_Selectors[i];
- Value *SelectorVal = new LoadInst(SelectorAddr, "select_val", true, I);
- I->replaceAllUsesWith(SelectorVal);
- }
+ IRBuilder<> Builder(EntryBB->getTerminator());
- // eh.exception calls are replaced with references to the proper location in
- // the context. Unlike eh.selector, the eh.exception calls are removed
- // entirely.
- for (int i = 0, e = EH_Exceptions.size(); i < e; ++i) {
- CallInst *I = EH_Exceptions[i];
- // Possible for there to be duplicates, so check to make sure the
- // instruction hasn't already been removed.
- if (!I->getParent()) continue;
- Value *Val = new LoadInst(ExceptionAddr, "exception", true, I);
- Type *Ty = Type::getInt8PtrTy(F.getContext());
- Val = CastInst::Create(Instruction::IntToPtr, Val, Ty, "", I);
-
- I->replaceAllUsesWith(Val);
- I->eraseFromParent();
- }
-
- for (unsigned i = 0, e = LandingPads.size(); i != e; ++i)
- ReplaceLandingPadVal(F, LandingPads[i], ExceptionAddr, SelectorAddr);
-
- // The entry block changes to have the eh.sjlj.setjmp, with a conditional
- // branch to a dispatch block for non-zero returns. If we return normally,
- // we're not handling an exception and just register the function context and
- // continue.
-
- // Create the dispatch block. The dispatch block is basically a big switch
- // statement that goes to all of the invoke landing pads.
- BasicBlock *DispatchBlock =
- BasicBlock::Create(F.getContext(), "eh.sjlj.setjmp.catch", &F);
-
- // Insert a load of the callsite in the dispatch block, and a switch on its
- // value. By default, we issue a trap statement.
- BasicBlock *TrapBlock =
- BasicBlock::Create(F.getContext(), "trapbb", &F);
- CallInst::Create(Intrinsic::getDeclaration(F.getParent(), Intrinsic::trap),
- "", TrapBlock);
- new UnreachableInst(F.getContext(), TrapBlock);
-
- Value *DispatchLoad = new LoadInst(CallSite, "invoke.num", true,
- DispatchBlock);
- SwitchInst *DispatchSwitch =
- SwitchInst::Create(DispatchLoad, TrapBlock, Invokes.size(),
- DispatchBlock);
- // Split the entry block to insert the conditional branch for the setjmp.
- BasicBlock *ContBlock = EntryBB->splitBasicBlock(EntryBB->getTerminator(),
- "eh.sjlj.setjmp.cont");
-
- // Populate the Function Context
- // 1. LSDA address
- // 2. Personality function address
- // 3. jmpbuf (save SP, FP and call eh.sjlj.setjmp)
-
- // LSDA address
- Idxs[0] = Zero;
- Idxs[1] = ConstantInt::get(Int32Ty, 4);
- Value *LSDAFieldPtr =
- GetElementPtrInst::Create(FunctionContext, Idxs, "lsda_gep",
- EntryBB->getTerminator());
- Value *LSDA = CallInst::Create(LSDAAddrFn, "lsda_addr",
- EntryBB->getTerminator());
- new StoreInst(LSDA, LSDAFieldPtr, true, EntryBB->getTerminator());
-
- Idxs[1] = ConstantInt::get(Int32Ty, 3);
- Value *PersonalityFieldPtr =
- GetElementPtrInst::Create(FunctionContext, Idxs, "lsda_gep",
- EntryBB->getTerminator());
- new StoreInst(PersonalityFn, PersonalityFieldPtr, true,
- EntryBB->getTerminator());
+ // Get a reference to the jump buffer.
+ Value *JBufPtr = Builder.CreateConstGEP2_32(FuncCtx, 0, 5, "jbuf_gep");
// Save the frame pointer.
- Idxs[1] = ConstantInt::get(Int32Ty, 5);
- Value *JBufPtr
- = GetElementPtrInst::Create(FunctionContext, Idxs, "jbuf_gep",
- EntryBB->getTerminator());
- Idxs[1] = ConstantInt::get(Int32Ty, 0);
- Value *FramePtr =
- GetElementPtrInst::Create(JBufPtr, Idxs, "jbuf_fp_gep",
- EntryBB->getTerminator());
-
- Value *Val = CallInst::Create(FrameAddrFn,
- ConstantInt::get(Int32Ty, 0),
- "fp",
- EntryBB->getTerminator());
- new StoreInst(Val, FramePtr, true, EntryBB->getTerminator());
+ Value *FramePtr = Builder.CreateConstGEP2_32(JBufPtr, 0, 0, "jbuf_fp_gep");
+
+ Value *Val = Builder.CreateCall(FrameAddrFn, Builder.getInt32(0), "fp");
+ Builder.CreateStore(Val, FramePtr, /*isVolatile=*/true);
// Save the stack pointer.
- Idxs[1] = ConstantInt::get(Int32Ty, 2);
- Value *StackPtr =
- GetElementPtrInst::Create(JBufPtr, Idxs, "jbuf_sp_gep",
- EntryBB->getTerminator());
+ Value *StackPtr = Builder.CreateConstGEP2_32(JBufPtr, 0, 2, "jbuf_sp_gep");
- Val = CallInst::Create(StackAddrFn, "sp", EntryBB->getTerminator());
- new StoreInst(Val, StackPtr, true, EntryBB->getTerminator());
+ Val = Builder.CreateCall(StackAddrFn, "sp");
+ Builder.CreateStore(Val, StackPtr, /*isVolatile=*/true);
// Call the setjmp instrinsic. It fills in the rest of the jmpbuf.
- Value *SetjmpArg =
- CastInst::Create(Instruction::BitCast, JBufPtr,
- Type::getInt8PtrTy(F.getContext()), "",
- EntryBB->getTerminator());
- Value *DispatchVal = CallInst::Create(BuiltinSetjmpFn, SetjmpArg,
- "dispatch",
- EntryBB->getTerminator());
+ Value *SetjmpArg = Builder.CreateBitCast(JBufPtr, Builder.getInt8PtrTy());
+ Builder.CreateCall(BuiltinSetjmpFn, SetjmpArg);
- // Add a call to dispatch_setup after the setjmp call. This is expanded to any
- // target-specific setup that needs to be done.
- CallInst::Create(DispatchSetupFn, DispatchVal, "", EntryBB->getTerminator());
+ // Store a pointer to the function context so that the back-end will know
+ // where to look for it.
+ Value *FuncCtxArg = Builder.CreateBitCast(FuncCtx, Builder.getInt8PtrTy());
+ Builder.CreateCall(FuncCtxFn, FuncCtxArg);
- // check the return value of the setjmp. non-zero goes to dispatcher.
- Value *IsNormal = new ICmpInst(EntryBB->getTerminator(),
- ICmpInst::ICMP_EQ, DispatchVal, Zero,
- "notunwind");
- // Nuke the uncond branch.
- EntryBB->getTerminator()->eraseFromParent();
+ // At this point, we are all set up, update the invoke instructions to mark
+ // their call_site values.
+ for (unsigned I = 0, E = Invokes.size(); I != E; ++I) {
+ insertCallSiteStore(Invokes[I], I + 1);
- // Put in a new condbranch in its place.
- BranchInst::Create(ContBlock, DispatchBlock, IsNormal, EntryBB);
+ ConstantInt *CallSiteNum =
+ ConstantInt::get(Type::getInt32Ty(F.getContext()), I + 1);
- // Register the function context and make sure it's known to not throw
- CallInst *Register =
- CallInst::Create(RegisterFn, FunctionContext, "",
- ContBlock->getTerminator());
- Register->setDoesNotThrow();
-
- // At this point, we are all set up, update the invoke instructions to mark
- // their call_site values, and fill in the dispatch switch accordingly.
- for (unsigned i = 0, e = Invokes.size(); i != e; ++i)
- markInvokeCallSite(Invokes[i], i+1, CallSite, DispatchSwitch);
+ // Record the call site value for the back end so it stays associated with
+ // the invoke.
+ CallInst::Create(CallSiteFn, CallSiteNum, "", Invokes[I]);
+ }
// Mark call instructions that aren't nounwind as no-action (call_site ==
// -1). Skip the entry block, as prior to then, no function context has been
// created for this function and any unexpected exceptions thrown will go
// directly to the caller's context, which is what we want anyway, so no need
// to do anything here.
- for (Function::iterator BB = F.begin(), E = F.end(); ++BB != E;) {
+ for (Function::iterator BB = F.begin(), E = F.end(); ++BB != E;)
for (BasicBlock::iterator I = BB->begin(), end = BB->end(); I != end; ++I)
if (CallInst *CI = dyn_cast<CallInst>(I)) {
- // Ignore calls to the EH builtins (eh.selector, eh.exception)
- Constant *Callee = CI->getCalledFunction();
- if (Callee != SelectorFn && Callee != ExceptionFn
- && !CI->doesNotThrow())
- insertCallSiteStore(CI, -1, CallSite);
+ if (!CI->doesNotThrow())
+ insertCallSiteStore(CI, -1);
+ } else if (ResumeInst *RI = dyn_cast<ResumeInst>(I)) {
+ insertCallSiteStore(RI, -1);
}
- }
- // Replace all unwinds with a branch to the unwind handler.
- // ??? Should this ever happen with sjlj exceptions?
- for (unsigned i = 0, e = Unwinds.size(); i != e; ++i) {
- BranchInst::Create(TrapBlock, Unwinds[i]);
- Unwinds[i]->eraseFromParent();
- }
+ // Register the function context and make sure it's known to not throw
+ CallInst *Register = CallInst::Create(RegisterFn, FuncCtx, "",
+ EntryBB->getTerminator());
+ Register->setDoesNotThrow();
// Following any allocas not in the entry block, update the saved SP in the
// jmpbuf to the new value.
- for (unsigned i = 0, e = JmpbufUpdatePoints.size(); i != e; ++i) {
- Instruction *AI = JmpbufUpdatePoints[i];
- Instruction *StackAddr = CallInst::Create(StackAddrFn, "sp");
- StackAddr->insertAfter(AI);
- Instruction *StoreStackAddr = new StoreInst(StackAddr, StackPtr, true);
- StoreStackAddr->insertAfter(StackAddr);
+ for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
+ if (BB == F.begin())
+ continue;
+ for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
+ if (CallInst *CI = dyn_cast<CallInst>(I)) {
+ if (CI->getCalledFunction() != StackRestoreFn)
+ continue;
+ } else if (!isa<AllocaInst>(I)) {
+ continue;
+ }
+ Instruction *StackAddr = CallInst::Create(StackAddrFn, "sp");
+ StackAddr->insertAfter(I);
+ Instruction *StoreStackAddr = new StoreInst(StackAddr, StackPtr, true);
+ StoreStackAddr->insertAfter(StackAddr);
+ }
}
// Finally, for any returns from this function, if this function contains an
// invoke, add a call to unregister the function context.
- for (unsigned i = 0, e = Returns.size(); i != e; ++i)
- CallInst::Create(UnregisterFn, FunctionContext, "", Returns[i]);
+ for (unsigned I = 0, E = Returns.size(); I != E; ++I)
+ CallInst::Create(UnregisterFn, FuncCtx, "", Returns[I]);
return true;
}
-bool SjLjEHPass::runOnFunction(Function &F) {
- bool Res = insertSjLjEHSupport(F);
+bool SjLjEHPrepare::runOnFunction(Function &F) {
+ bool Res = setupEntryBlockAndCallSites(F);
return Res;
}
projects / oota-llvm.git / blobdiff