#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
-#include "llvm/CodeGen/Passes.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Compiler.h"
+#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetLowering.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/Local.h"
#include <set>
using namespace llvm;
STATISTIC(NumSpilled, "Number of registers live across unwind edges");
namespace {
- class VISIBILITY_HIDDEN SjLjEHPass : public FunctionPass {
+ class SjLjEHPass : public FunctionPass {
const TargetLowering *TLI;
const Type *FunctionContextTy;
Constant *RegisterFn;
Constant *UnregisterFn;
- Constant *ResumeFn;
Constant *BuiltinSetjmpFn;
Constant *FrameAddrFn;
+ Constant *StackAddrFn;
+ Constant *StackRestoreFn;
Constant *LSDAAddrFn;
Value *PersonalityFn;
- Constant *Selector32Fn;
- Constant *Selector64Fn;
+ Constant *SelectorFn;
Constant *ExceptionFn;
+ Constant *CallSiteFn;
+ Constant *DispatchSetupFn;
Value *CallSite;
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);
}
private:
- void markInvokeCallSite(InvokeInst *II, unsigned InvokeNo,
- Value *CallSite,
+ void insertCallSiteStore(Instruction *I, int Number, Value *CallSite);
+ void markInvokeCallSite(InvokeInst *II, int InvokeNo, Value *CallSite,
SwitchInst *CatchSwitch);
- void splitLiveRangesLiveAcrossInvokes(std::vector<InvokeInst*> &Invokes);
+ void splitLiveRangesAcrossInvokes(SmallVector<InvokeInst*,16> &Invokes);
bool insertSjLjEHSupport(Function &F);
};
} // end anonymous namespace
FunctionPass *llvm::createSjLjEHPass(const TargetLowering *TLI) {
return new SjLjEHPass(TLI);
}
-// doInitialization - Make sure that there is a prototype for abort in the
-// current module.
+// doInitialization - Set up decalarations and types needed to process
+// exceptions.
bool SjLjEHPass::doInitialization(Module &M) {
// Build the function context structure.
// builtin_setjmp uses a five word jbuf
const Type *VoidPtrTy =
- PointerType::getUnqual(Type::getInt8Ty(M.getContext()));
+ Type::getInt8PtrTy(M.getContext());
const Type *Int32Ty = Type::getInt32Ty(M.getContext());
FunctionContextTy =
StructType::get(M.getContext(),
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);
- Selector32Fn = Intrinsic::getDeclaration(&M, Intrinsic::eh_selector_i32);
- Selector64Fn = Intrinsic::getDeclaration(&M, Intrinsic::eh_selector_i64);
+ 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
+}
+
/// 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()),
}
}
- // 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?
+ // 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
MarkBlocksLiveIn(*PI, LiveBBs);
}
-// 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 - 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::
-splitLiveRangesLiveAcrossInvokes(std::vector<InvokeInst*> &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];
++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.
continue;
// Avoid iterator invalidation by copying users to a temporary vector.
- std::vector<Instruction*> Users;
+ SmallVector<Instruction*,16> Users;
for (Value::use_iterator UI = Inst->use_begin(), E = Inst->use_end();
UI != E; ++UI) {
Instruction *User = cast<Instruction>(*UI);
Users.push_back(User);
}
- // Scan all of the uses and see if the live range is live across an unwind
- // edge. If we find a use live across an invoke edge, create an alloca
- // and spill the value.
- std::set<InvokeInst*> InvokesWithStoreInserted;
-
// Find all of the blocks that this value is live in.
std::set<BasicBlock*> LiveBBs;
LiveBBs.insert(Inst->getParent());
}
// 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);
}
bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
- std::vector<ReturnInst*> Returns;
- std::vector<UnwindInst*> Unwinds;
- std::vector<InvokeInst*> Invokes;
+ 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;
+ // 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;
+ // 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->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);
+ }
+ }
+ }
+ // 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();
-
if (!Invokes.empty()) {
// We have invokes, so we need to add register/unregister calls to get
// this function onto the global unwind stack.
// 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
"exception_gep",
EntryBB->getTerminator());
- // Find the eh.selector.* and eh.exception calls. We'll use the first
- // ex.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?
- std::vector<CallInst*> EH_Selectors;
- std::vector<CallInst*> EH_Exceptions;
- for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
- // for (unsigned i = 0, e = Invokes.size(); i != e; ++i) {
-// BasicBlock *Pad = Invokes[0]->getUnwindDest();
- for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
- if (CallInst *CI = dyn_cast<CallInst>(I)) {
- if (CI->getCalledFunction() == Selector32Fn ||
- CI->getCalledFunction() == Selector64Fn) {
- if (!PersonalityFn) PersonalityFn = CI->getOperand(2);
- EH_Selectors.push_back(CI);
- } else if (CI->getCalledFunction() == ExceptionFn) {
- EH_Exceptions.push_back(CI);
- }
- }
- }
- }
// 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
// the instruction hasn't already been removed.
if (!I->getParent()) continue;
Value *Val = new LoadInst(ExceptionAddr, "exception", true, I);
- Val = CastInst::Create(Instruction::IntToPtr, Val,
- PointerType::getUnqual(Type::getInt8Ty(F.getContext())),
- "", 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
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);
+ // Add a call to dispatch_setup at the start of the dispatch block. This
+ // is expanded to any target-specific setup that needs to be done.
+ Value *SetupArg =
+ CastInst::Create(Instruction::BitCast, FunctionContext,
+ Type::getInt8PtrTy(F.getContext()), "",
+ DispatchBlock);
+ CallInst::Create(DispatchSetupFn, SetupArg, "", DispatchBlock);
+
+ // Insert a load of the callsite in the dispatch 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);
+ 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)
+ // 3. jmpbuf (save SP, FP and call eh.sjlj.setjmp)
// LSDA address
Idxs[0] = Zero;
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,
- Type::getInt8Ty(F.getContext())->getPointerTo(), "",
- EntryBB->getTerminator());
+ 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");
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
- }
+ // 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);
}
- }
+ }
// Replace all unwinds with a branch to the unwind handler.
// ??? Should this ever happen with sjlj exceptions?
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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