#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/CodeGen/Passes.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetLowering.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetLowering.h"
+#include "llvm/Support/IRBuilder.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
+#include <set>
using namespace llvm;
+static cl::opt<bool> DisableOldSjLjEH("disable-old-sjlj-eh", cl::Hidden,
+ cl::desc("Disable the old SjLj EH preparation pass"));
+
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 {
-
const TargetLowering *TLI;
-
- const Type *FunctionContextTy;
+ Type *FunctionContextTy;
Constant *RegisterFn;
Constant *UnregisterFn;
- Constant *ResumeFn;
Constant *BuiltinSetjmpFn;
Constant *FrameAddrFn;
+ Constant *StackAddrFn;
+ Constant *StackRestoreFn;
Constant *LSDAAddrFn;
Value *PersonalityFn;
Constant *SelectorFn;
Constant *ExceptionFn;
-
+ Constant *CallSiteFn;
+ Constant *DispatchSetupFn;
Value *CallSite;
+ DenseMap<InvokeInst*, BasicBlock*> LPadSuccMap;
public:
static char ID; // Pass identification, replacement for typeid
explicit SjLjEHPass(const TargetLowering *tli = NULL)
- : FunctionPass(&ID), TLI(tli) { }
+ : FunctionPass(ID), TLI(tli) { }
bool doInitialization(Module &M);
bool runOnFunction(Function &F);
- virtual void getAnalysisUsage(AnalysisUsage &AU) const { }
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {}
const char *getPassName() const {
return "SJLJ Exception Handling preparation";
}
private:
- void markInvokeCallSite(InvokeInst *II, unsigned InvokeNo,
- Value *CallSite,
+ bool setupEntryBlockAndCallSites(Function &F);
+ void setupFunctionContext(Function &F, ArrayRef<LandingPadInst*> LPads);
+
+ void insertCallSiteStore(Instruction *I, int Number, Value *CallSite);
+ void markInvokeCallSite(InvokeInst *II, int InvokeNo, Value *CallSite,
SwitchInst *CatchSwitch);
- void splitLiveRangesLiveAcrossInvokes(SmallVector<InvokeInst*,16> &Invokes);
+ void splitLiveRangesAcrossInvokes(SmallVector<InvokeInst*,16> &Invokes);
+ void splitLandingPad(InvokeInst *II);
bool insertSjLjEHSupport(Function &F);
};
} // end anonymous namespace
bool SjLjEHPass::doInitialization(Module &M) {
// Build the function context structure.
// builtin_setjmp uses a five word jbuf
- const Type *VoidPtrTy =
- Type::getInt8PtrTy(M.getContext());
- const Type *Int32Ty = Type::getInt32Ty(M.getContext());
+ Type *VoidPtrTy = Type::getInt8PtrTy(M.getContext());
+ Type *Int32Ty = Type::getInt32Ty(M.getContext());
FunctionContextTy =
- StructType::get(M.getContext(),
- VoidPtrTy, // __prev
+ StructType::get(VoidPtrTy, // __prev
Int32Ty, // call_site
ArrayType::get(Int32Ty, 4), // __data
VoidPtrTy, // __personality
Type::getVoidTy(M.getContext()),
PointerType::getUnqual(FunctionContextTy),
(Type *)0);
- ResumeFn =
- M.getOrInsertFunction("_Unwind_SjLj_Resume",
- Type::getVoidTy(M.getContext()),
- VoidPtrTy,
- (Type *)0);
FrameAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::frameaddress);
+ StackAddrFn = Intrinsic::getDeclaration(&M, Intrinsic::stacksave);
+ 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);
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) {
+ ConstantInt *CallSiteNoC = ConstantInt::get(Type::getInt32Ty(I->getContext()),
+ Number);
+ // Insert a store of the call-site number
+ new StoreInst(CallSiteNoC, CallSite, true, I); // volatile
+}
+
+/// splitLandingPad - Split a landing pad. This takes considerable care because
+/// of PHIs and other nasties. The problem is that the jump table needs to jump
+/// to the landing pad block. However, the landing pad block can be jumped to
+/// only by an invoke instruction. So we clone the landingpad instruction into
+/// its own basic block, have the invoke jump to there. The landingpad
+/// instruction's basic block's successor is now the target for the jump table.
+///
+/// But because of PHI nodes, we need to create another basic block for the jump
+/// table to jump to. This is definitely a hack, because the values for the PHI
+/// nodes may not be defined on the edge from the jump table. But that's okay,
+/// because the jump table is simply a construct to mimic what is happening in
+/// the CFG. So the values are mysteriously there, even though there is no value
+/// for the PHI from the jump table's edge (hence calling this a hack).
+void SjLjEHPass::splitLandingPad(InvokeInst *II) {
+ SmallVector<BasicBlock*, 2> NewBBs;
+ SplitLandingPadPredecessors(II->getUnwindDest(), II->getParent(),
+ ".1", ".2", this, NewBBs);
+
+ // Create an empty block so that the jump table has something to jump to
+ // which doesn't have any PHI nodes.
+ BasicBlock *LPad = NewBBs[0];
+ BasicBlock *Succ = *succ_begin(LPad);
+ BasicBlock *JumpTo = BasicBlock::Create(II->getContext(), "jt.land",
+ LPad->getParent(), Succ);
+ LPad->getTerminator()->eraseFromParent();
+ BranchInst::Create(JumpTo, LPad);
+ BranchInst::Create(Succ, JumpTo);
+ LPadSuccMap[II] = JumpTo;
+
+ for (BasicBlock::iterator I = Succ->begin(); isa<PHINode>(I); ++I) {
+ PHINode *PN = cast<PHINode>(I);
+ Value *Val = PN->removeIncomingValue(LPad, false);
+ PN->addIncoming(Val, JumpTo);
+ }
+}
+
/// markInvokeCallSite - Insert code to mark the call_site for this invoke
-void SjLjEHPass::markInvokeCallSite(InvokeInst *II, unsigned InvokeNo,
+void SjLjEHPass::markInvokeCallSite(InvokeInst *II, int InvokeNo,
Value *CallSite,
SwitchInst *CatchSwitch) {
ConstantInt *CallSiteNoC= ConstantInt::get(Type::getInt32Ty(II->getContext()),
- InvokeNo);
+ 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);
+ InvokeNo - 1);
// If the unwind edge has phi nodes, split the edge.
if (isa<PHINode>(II->getUnwindDest()->begin())) {
- SplitCriticalEdge(II, 1, this);
+ // FIXME: New EH - This if-condition will be always true in the new scheme.
+ if (II->getUnwindDest()->isLandingPad())
+ splitLandingPad(II);
+ else
+ 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())) {
}
}
- // Insert a store of the invoke num before the invoke and store zero into the
- // location afterward.
- new StoreInst(CallSiteNoC, CallSite, true, II); // volatile
+ // Insert the store of the call site value
+ insertCallSiteStore(II, InvokeNo, CallSite);
+
+ // Record the call site value for the back end so it stays associated with
+ // the invoke.
+ CallInst::Create(CallSiteFn, CallSiteNoC, "", II);
// Add a switch case to our unwind block.
- CatchSwitch->addCase(SwitchValC, II->getUnwindDest());
- // We still want this to look like an invoke so we emit the LSDA properly
- // FIXME: ??? Or will this cause strangeness with mis-matched IDs like
- // when it was in the front end?
+ if (BasicBlock *SuccBB = LPadSuccMap[II]) {
+ CatchSwitch->addCase(SwitchValC, SuccBB);
+ } else {
+ CatchSwitch->addCase(SwitchValC, II->getUnwindDest());
+ }
+
+ // 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.
}
/// MarkBlocksLiveIn - Insert BB and all of its predescessors into LiveBBs until
/// 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::
-splitLiveRangesLiveAcrossInvokes(SmallVector<InvokeInst*,16> &Invokes) {
+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);
- SplitCriticalEdge(II, 1, this);
+
+ // FIXME: New EH - This if-condition will be always true in the new scheme.
+ if (II->getUnwindDest()->isLandingPad())
+ splitLandingPad(II);
+ else
+ SplitCriticalEdge(II, 1, this);
+
assert(!isa<PHINode>(II->getNormalDest()) &&
!isa<PHINode>(II->getUnwindDest()) &&
- "critical edge splitting left single entry phi nodes?");
+ "Critical edge splitting left single entry phi nodes?");
}
Function *F = Invokes.back()->getParent()->getParent();
++AfterAllocaInsertPt;
for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
AI != E; ++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);
- AI->replaceAllUsesWith(NC);
- // Normally its is 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 to simply
- // make NC its user.
- NC->setOperand(0, 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 *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);
+ } else {
+ // 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);
+ 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.
+ NC->setOperand(0, AI);
+ }
}
// Finally, scan the code looking for instructions with bad live ranges.
}
// If we decided we need a spill, do it.
+ // FIXME: Spilling this way is overkill, as it forces all uses of
+ // 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);
}
}
+/// 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;
+ }
+
+ I->replaceUsesOfWith(Inst, CreateLandingPadLoad(F, ExnAddr, SelAddr, I));
+ }
+}
+
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)
+ // 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.
} else if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
Unwinds.push_back(UI);
}
- // If we don't have any invokes or unwinds, there's nothing to do.
- if (Unwinds.empty() && Invokes.empty()) return false;
+ }
+
+ NumInvokes += Invokes.size();
+ NumUnwinds += Unwinds.size();
- // Find the eh.selector.* and eh.exception calls. 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.
+ // 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->getOperand(2);
+ 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;
- NumInvokes += Invokes.size();
- NumUnwinds += Unwinds.size();
+ // 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);
+ }
- if (!Invokes.empty()) {
- // 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.
- splitLiveRangesLiveAcrossInvokes(Invokes);
-
- 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];
- const 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, Idxs+2,
- "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, Idxs+2,
- "fc_data",
- EntryBB->getTerminator());
- Idxs[1] = ConstantInt::get(Int32Ty, 1);
- Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2,
- "exc_selector_gep",
- EntryBB->getTerminator());
- // The exception value comes back in context->data[0]
- Idxs[1] = Zero;
- Value *ExceptionAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2,
- "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);
- }
- // 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);
- const Type *Ty = Type::getInt8PtrTy(F.getContext());
- Val = CastInst::Create(Instruction::IntToPtr, Val, Ty, "", I);
-
- I->replaceAllUsesWith(Val);
- I->eraseFromParent();
- }
- // 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 in the Catch block, and a switch on its value. By default,
- // we go to a block that just does an unwind (which is the correct action
- // for a standard call).
- BasicBlock *UnwindBlock =
- BasicBlock::Create(F.getContext(), "unwindbb", &F);
- Unwinds.push_back(new UnwindInst(F.getContext(), UnwindBlock));
-
- Value *DispatchLoad = new LoadInst(CallSite, "invoke.num", true,
- DispatchBlock);
- SwitchInst *DispatchSwitch =
- SwitchInst::Create(DispatchLoad, UnwindBlock, 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 FP and call eh.sjlj.setjmp)
-
- // LSDA address
- Idxs[0] = Zero;
- Idxs[1] = ConstantInt::get(Int32Ty, 4);
- Value *LSDAFieldPtr =
- GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
- "lsda_gep",
+ 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);
+ }
+
+ // 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());
+
+ // Save the frame pointer.
+ Idxs[1] = ConstantInt::get(Int32Ty, 5);
+ Value *JBufPtr
+ = GetElementPtrInst::Create(FunctionContext, Idxs, "jbuf_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, Idxs+2,
- "lsda_gep",
+ 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(PersonalityFn, PersonalityFieldPtr, true,
- EntryBB->getTerminator());
-
- // Save the frame pointer.
- Idxs[1] = ConstantInt::get(Int32Ty, 5);
- Value *FieldPtr
- = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
- "jbuf_gep",
- EntryBB->getTerminator());
- Idxs[1] = ConstantInt::get(Int32Ty, 0);
- Value *ElemPtr =
- GetElementPtrInst::Create(FieldPtr, Idxs, Idxs+2, "jbuf_fp_gep",
+ new StoreInst(Val, FramePtr, true, EntryBB->getTerminator());
+
+ // Save the stack pointer.
+ Idxs[1] = ConstantInt::get(Int32Ty, 2);
+ Value *StackPtr =
+ GetElementPtrInst::Create(JBufPtr, Idxs, "jbuf_sp_gep",
+ EntryBB->getTerminator());
+
+ Val = CallInst::Create(StackAddrFn, "sp", EntryBB->getTerminator());
+ new StoreInst(Val, StackPtr, true, EntryBB->getTerminator());
+
+ // 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());
+
+ // 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());
+
+ // 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();
+
+ // Put in a new condbranch in its place.
+ BranchInst::Create(ContBlock, DispatchBlock, IsNormal, EntryBB);
+
+ // 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);
+
+ // 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 (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);
+ } else if (ResumeInst *RI = dyn_cast<ResumeInst>(I)) {
+ insertCallSiteStore(RI, -1, CallSite);
+ }
+ }
+
+ // 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();
+ }
+
+ // 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);
+ }
+
+ // 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]);
+
+ return true;
+}
+
+/// setupFunctionContext - Allocate the function context on the stack and fill
+/// it with all of the data that we know at this point.
+void SjLjEHPass::setupFunctionContext(Function &F,
+ ArrayRef<LandingPadInst*> LPads) {
+ 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 =
+ TLI->getTargetData()->getPrefTypeAlignment(FunctionContextTy);
+ AllocaInst *FuncCtx =
+ new AllocaInst(FunctionContextTy, 0, Align, "fn_context", EntryBB->begin());
+
+ // Fill in the function context structure.
+ Value *Idxs[2];
+ Type *Int32Ty = Type::getInt32Ty(F.getContext());
+ Value *Zero = ConstantInt::get(Int32Ty, 0);
+ Value *One = ConstantInt::get(Int32Ty, 1);
+
+ // Keep around a reference to the call_site field.
+ Idxs[0] = Zero;
+ Idxs[1] = One;
+ CallSite = GetElementPtrInst::Create(FuncCtx, Idxs, "call_site",
+ EntryBB->getTerminator());
+
+ // Reference the __data field.
+ Idxs[1] = ConstantInt::get(Int32Ty, 2);
+ Value *FCData = GetElementPtrInst::Create(FuncCtx, Idxs, "__data",
+ 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 exception selector comes back in context->__data[1].
+ Idxs[1] = One;
+ Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs,
+ "exn_selector_gep",
+ EntryBB->getTerminator());
+
+ for (unsigned I = 0, E = LPads.size(); I != E; ++I) {
+ LandingPadInst *LPI = LPads[I];
+ IRBuilder<> Builder(LPI->getParent()->getFirstInsertionPt());
+
+ Value *ExnVal = Builder.CreateLoad(ExceptionAddr, true, "exn_val");
+ ExnVal = Builder.CreateIntToPtr(ExnVal, Type::getInt8PtrTy(F.getContext()));
+ Value *SelVal = Builder.CreateLoad(SelectorAddr, true, "exn_selector_val");
+
+ Type *LPadType = LPI->getType();
+ Value *LPadVal = UndefValue::get(LPadType);
+ LPadVal = Builder.CreateInsertValue(LPadVal, ExnVal, 0, "lpad.val");
+ LPadVal = Builder.CreateInsertValue(LPadVal, SelVal, 1, "lpad.val");
+
+ LPI->replaceAllUsesWith(LPadVal);
+ }
+
+ // Personality function
+ Idxs[1] = ConstantInt::get(Int32Ty, 3);
+ if (!PersonalityFn)
+ PersonalityFn = LPads[0]->getPersonalityFn();
+ Value *PersonalityFieldPtr =
+ GetElementPtrInst::Create(FuncCtx, Idxs, "pers_fn_gep",
+ EntryBB->getTerminator());
+ new StoreInst(PersonalityFn, PersonalityFieldPtr, true,
+ EntryBB->getTerminator());
+
+ // LSDA address
+ Idxs[1] = ConstantInt::get(Int32Ty, 4);
+ Value *LSDAFieldPtr =
+ GetElementPtrInst::Create(FuncCtx, Idxs, "lsda_gep",
+ EntryBB->getTerminator());
+ Value *LSDA = CallInst::Create(LSDAAddrFn, "lsda_addr",
+ EntryBB->getTerminator());
+ new StoreInst(LSDA, LSDAFieldPtr, true, EntryBB->getTerminator());
+
+ // Get a reference to the jump buffer.
+ Idxs[1] = ConstantInt::get(Int32Ty, 5);
+ Value *JBufPtr =
+ GetElementPtrInst::Create(FuncCtx, Idxs, "jbuf_gep",
+ EntryBB->getTerminator());
+ Idxs[1] = Zero;
+ Value *FramePtr =
+ GetElementPtrInst::Create(JBufPtr, Idxs, "jbuf_fp_gep",
+ EntryBB->getTerminator());
+
+ // Save the frame pointer.
+ Value *Val = CallInst::Create(FrameAddrFn,
+ ConstantInt::get(Int32Ty, 0),
+ "fp",
EntryBB->getTerminator());
+ new StoreInst(Val, FramePtr, true, EntryBB->getTerminator());
+
+ // Save the stack pointer.
+ Idxs[1] = ConstantInt::get(Int32Ty, 2);
+ Value *StackPtr =
+ GetElementPtrInst::Create(JBufPtr, Idxs, "jbuf_sp_gep",
+ EntryBB->getTerminator());
+
+ Val = CallInst::Create(StackAddrFn, "sp", EntryBB->getTerminator());
+ new StoreInst(Val, StackPtr, true, EntryBB->getTerminator());
+
+ // 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());
+
+ // 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());
+}
- Value *Val = CallInst::Create(FrameAddrFn,
- ConstantInt::get(Int32Ty, 0),
- "fp",
- EntryBB->getTerminator());
- new StoreInst(Val, ElemPtr, true, EntryBB->getTerminator());
- // Call the setjmp instrinsic. It fills in the rest of the jmpbuf
- Value *SetjmpArg =
- CastInst::Create(Instruction::BitCast, FieldPtr,
- Type::getInt8PtrTy(F.getContext()), "",
- EntryBB->getTerminator());
- Value *DispatchVal = CallInst::Create(BuiltinSetjmpFn, SetjmpArg,
- "dispatch",
- EntryBB->getTerminator());
- // 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();
-
- // Put in a new condbranch in its place.
- BranchInst::Create(ContBlock, DispatchBlock, IsNormal, EntryBB);
-
- // 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);
-
- // The front end has likely added calls to _Unwind_Resume. We need
- // to find those calls and mark the call_site as -1 immediately prior.
- // resume is a noreturn function, so any block that has a call to it
- // should end in an 'unreachable' instruction with the call immediately
- // prior. That's how we'll search.
- // ??? There's got to be a better way. this is fugly.
- for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
- if ((dyn_cast<UnreachableInst>(BB->getTerminator()))) {
- BasicBlock::iterator I = BB->getTerminator();
- // Check the previous instruction and see if it's a resume call
- if (I == BB->begin()) continue;
- if (CallInst *CI = dyn_cast<CallInst>(--I)) {
- if (CI->getCalledFunction() == ResumeFn) {
- Value *NegativeOne = Constant::getAllOnesValue(Int32Ty);
- new StoreInst(NegativeOne, CallSite, true, I); // volatile
- }
- }
- }
+/// 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 SjLjEHPass::setupEntryBlockAndCallSites(Function &F) {
+ SmallVector<InvokeInst*, 16> Invokes;
+ SmallVector<LandingPadInst*, 16> LPads;
- // 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(UnwindBlock, Unwinds[i]);
- Unwinds[i]->eraseFromParent();
+ // 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);
+ LPads.push_back(II->getUnwindDest()->getLandingPadInst());
}
- // 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]);
+ if (Invokes.empty()) return false;
+
+ setupFunctionContext(F, LPads);
+
+ // 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) {
+ insertCallSiteStore(Invokes[I], I + 1, CallSite);
+
+ ConstantInt *CallSiteNum =
+ ConstantInt::get(Type::getInt32Ty(F.getContext()), I + 1);
+
+ // 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 (BasicBlock::iterator I = BB->begin(), end = BB->end(); I != end; ++I)
+ if (CallInst *CI = dyn_cast<CallInst>(I)) {
+ if (!CI->doesNotThrow())
+ insertCallSiteStore(CI, -1, CallSite);
+ } else if (ResumeInst *RI = dyn_cast<ResumeInst>(I)) {
+ insertCallSiteStore(RI, -1, CallSite);
+ }
}
return true;
}
bool SjLjEHPass::runOnFunction(Function &F) {
- bool Res = insertSjLjEHSupport(F);
+ bool Res = false;
+ if (!DisableOldSjLjEH)
+ Res = insertSjLjEHSupport(F);
+ else
+ Res = setupEntryBlockAndCallSites(F);
return Res;
}
projects / oota-llvm.git / blobdiff