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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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78
llvm/lib/CodeGen/SjLjEHPrepare.cpp
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@ -319,8 +319,12 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
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.
//
@ -334,6 +338,7 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
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.
@ -353,22 +358,19 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
}
}
}
// 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 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.
// 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);
BasicBlock *EntryBB = F.begin();
@ -405,22 +407,22 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
"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.
// 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.
// 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.
// 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());
@ -432,25 +434,25 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
// 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.
// 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.
// 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).
// 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));
@ -538,17 +540,16 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
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.
// 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.
// 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)) {
@ -567,8 +568,8 @@ 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.
// 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");
@ -581,7 +582,6 @@ bool SjLjEHPass::insertSjLjEHSupport(Function &F) {
// 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;
}