diff options
Diffstat (limited to 'lib/CodeGen/SjLjEHPrepare.cpp')
| -rw-r--r-- | lib/CodeGen/SjLjEHPrepare.cpp | 114 |
1 files changed, 86 insertions, 28 deletions
diff --git a/lib/CodeGen/SjLjEHPrepare.cpp b/lib/CodeGen/SjLjEHPrepare.cpp index 059e8d6c19aa..e90869d600dd 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) |