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Early exit if we don't have invokes. The 'Unwinds' vector isn't modified unless 

we have invokes, so there is no functionality change here.

llvm-svn: 122990
This commit is contained in:
Bill Wendling 2011-01-07 02:54:45 +00:00
parent db59823068
commit 34e2bc0f08
1 changed files with 222 additions and 222 deletions
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444
llvm/lib/CodeGen/SjLjEHPrepare.cpp
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@ -319,8 +319,12 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
Unwinds.push_back(UI); 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();
// 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. // Find the eh.selector.*, eh.exception and alloca calls.
// //
@ -334,6 +338,7 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
SmallVector<CallInst*,16> EH_Selectors; SmallVector<CallInst*,16> EH_Selectors;
SmallVector<CallInst*,16> EH_Exceptions; SmallVector<CallInst*,16> EH_Exceptions;
SmallVector<Instruction*,16> JmpbufUpdatePoints; SmallVector<Instruction*,16> JmpbufUpdatePoints;
// Note: Skip the entry block since there's nothing there that interests // 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 // us. eh.selector and eh.exception shouldn't ever be there, and we
// want to disregard any allocas that are there. // want to disregard any allocas that are there.
@ -353,236 +358,231 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
} }
} }
} }
// If we don't have any eh.selector calls, we can't determine the personality // 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. // function. Without a personality function, we can't process exceptions.
if (!PersonalityFn) return false; if (!PersonalityFn) return false;
NumInvokes += Invokes.size(); // We have invokes, so we need to add register/unregister calls to get this
NumUnwinds += Unwinds.size(); // 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);
if (!Invokes.empty()) { BasicBlock *EntryBB = F.begin();
// We have invokes, so we need to add register/unregister calls to get // Create an alloca for the incoming jump buffer ptr and the new jump buffer
// this function onto the global unwind stack. // 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.
// First thing we need to do is scan the whole function for values that are unsigned Align = 4; // FIXME: Should be a TLI check?
// live across unwind edges. Each value that is live across an unwind edge AllocaInst *FunctionContext =
// we spill into a stack location, guaranteeing that there is nothing live new AllocaInst(FunctionContextTy, 0, Align,
// across the unwind edge. This process also splits all critical edges "fcn_context", F.begin()->begin());
// coming out of invoke's.
splitLiveRangesAcrossInvokes(Invokes);
BasicBlock *EntryBB = F.begin(); Value *Idxs[2];
// Create an alloca for the incoming jump buffer ptr and the new jump buffer const Type *Int32Ty = Type::getInt32Ty(F.getContext());
// that needs to be restored on all exits from the function. This is an Value *Zero = ConstantInt::get(Int32Ty, 0);
// alloca because the value needs to be added to the global context list. // We need to also keep around a reference to the call_site field
unsigned Align = 4; // FIXME: Should be a TLI check? Idxs[0] = Zero;
AllocaInst *FunctionContext = Idxs[1] = ConstantInt::get(Int32Ty, 1);
new AllocaInst(FunctionContextTy, 0, Align, CallSite = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
"fcn_context", F.begin()->begin()); "call_site",
EntryBB->getTerminator());
Value *Idxs[2]; // The exception selector comes back in context->data[1]
const Type *Int32Ty = Type::getInt32Ty(F.getContext()); Idxs[1] = ConstantInt::get(Int32Ty, 2);
Value *Zero = ConstantInt::get(Int32Ty, 0); Value *FCData = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2,
// We need to also keep around a reference to the call_site field "fc_data",
Idxs[0] = Zero; EntryBB->getTerminator());
Idxs[1] = ConstantInt::get(Int32Ty, 1); Idxs[1] = ConstantInt::get(Int32Ty, 1);
CallSite = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2,
"call_site", "exc_selector_gep",
EntryBB->getTerminator()); 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 exception selector comes back in context->data[1] // The result of the eh.selector call will be replaced with a a reference to
Idxs[1] = ConstantInt::get(Int32Ty, 2); // the selector value returned in the function context. We leave the selector
Value *FCData = GetElementPtrInst::Create(FunctionContext, Idxs, Idxs+2, // itself so the EH analysis later can use it.
"fc_data", for (int i = 0, e = EH_Selectors.size(); i < e; ++i) {
EntryBB->getTerminator()); CallInst *I = EH_Selectors[i];
Idxs[1] = ConstantInt::get(Int32Ty, 1); Value *SelectorVal = new LoadInst(SelectorAddr, "select_val", true, I);
Value *SelectorAddr = GetElementPtrInst::Create(FCData, Idxs, Idxs+2, I->replaceAllUsesWith(SelectorVal);
"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);
// 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);
// 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, Idxs+2,
"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, Idxs+2,
"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, Idxs+2,
"jbuf_gep",
EntryBB->getTerminator());
Idxs[1] = ConstantInt::get(Int32Ty, 0);
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, 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, 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.
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);
}
}
// 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();
}
// 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]);
} }
// 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);
// 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);
// 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, Idxs+2,
"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, Idxs+2,
"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, Idxs+2,
"jbuf_gep",
EntryBB->getTerminator());
Idxs[1] = ConstantInt::get(Int32Ty, 0);
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, 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, 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.
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);
}
}
// 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();
}
// 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; return true;
} }