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-rw-r--r--lib/CodeGen/SjLjEHPrepare.cpp114
1 files changed, 86 insertions, 28 deletions
diff --git a/lib/CodeGen/SjLjEHPrepare.cpp b/lib/CodeGen/SjLjEHPrepare.cpp
index 059e8d6..e90869d 100644
--- a/lib/CodeGen/SjLjEHPrepare.cpp
+++ b/lib/CodeGen/SjLjEHPrepare.cpp
@@ -46,6 +46,8 @@ namespace {
Constant *UnregisterFn;
Constant *BuiltinSetjmpFn;
Constant *FrameAddrFn;
+ Constant *StackAddrFn;
+ Constant *StackRestoreFn;
Constant *LSDAAddrFn;
Value *PersonalityFn;
Constant *SelectorFn;
@@ -69,7 +71,7 @@ namespace {
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);
bool insertSjLjEHSupport(Function &F);
};
} // end anonymous namespace
@@ -107,6 +109,8 @@ bool SjLjEHPass::doInitialization(Module &M) {
PointerType::getUnqual(FunctionContextTy),
(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);
@@ -175,8 +179,10 @@ static void MarkBlocksLiveIn(BasicBlock *BB, std::set<BasicBlock*> &LiveBBs) {
/// 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];
@@ -198,16 +204,33 @@ splitLiveRangesLiveAcrossInvokes(SmallVector<InvokeInst*,16> &Invokes) {
++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);
+ const 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.
@@ -266,6 +289,9 @@ splitLiveRangesLiveAcrossInvokes(SmallVector<InvokeInst*,16> &Invokes) {
}
// 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);
@@ -294,22 +320,34 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
// If we don't have any invokes or unwinds, there's nothing to do.
if (Unwinds.empty() && Invokes.empty()) return false;
- // 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.
+ // 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;
- for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
+ SmallVector<Instruction*,16> JmpbufUpdatePoints;
+ // 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.
+ for (Function::iterator BB = F.begin(), E = F.end(); ++BB != E;) {
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);
}
}
}
@@ -329,7 +367,7 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
// 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);
+ splitLiveRangesAcrossInvokes(Invokes);
BasicBlock *EntryBB = F.begin();
// Create an alloca for the incoming jump buffer ptr and the new jump buffer
@@ -419,7 +457,7 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
// Populate the Function Context
// 1. LSDA address
// 2. Personality function address
- // 3. jmpbuf (save FP and call eh.sjlj.setjmp)
+ // 3. jmpbuf (save SP, FP and call eh.sjlj.setjmp)
// LSDA address
Idxs[0] = Zero;
@@ -440,31 +478,41 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
new StoreInst(PersonalityFn, PersonalityFieldPtr, true,
EntryBB->getTerminator());
- // Save the frame pointer.
+ // Save the frame pointer.
Idxs[1] = ConstantInt::get(Int32Ty, 5);
- Value *FieldPtr
+ Value *JBufPtr
= 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",
+ Value *FramePtr =
+ GetElementPtrInst::Create(JBufPtr, Idxs, Idxs+2, "jbuf_fp_gep",
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
+ new StoreInst(Val, FramePtr, true, EntryBB->getTerminator());
+
+ // Save the stack pointer.
+ Idxs[1] = ConstantInt::get(Int32Ty, 2);
+ Value *StackPtr =
+ GetElementPtrInst::Create(JBufPtr, Idxs, Idxs+2, "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, FieldPtr,
+ CastInst::Create(Instruction::BitCast, JBufPtr,
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
+ // check the return value of the setjmp. non-zero goes to dispatcher.
Value *IsNormal = new ICmpInst(EntryBB->getTerminator(),
ICmpInst::ICMP_EQ, DispatchVal, Zero,
"notunwind");
@@ -509,6 +557,16 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
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)
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