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Initial stab at getting inlining working with the EH rewrite.

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This takes the new 'resume' instruction and turns it into a direct jump to the
caller's landing pad code. The caller's landingpad instruction is merged with
the landingpad instructions of the callee. This is a bit rough and makes some
assumptions in how the code works. But it passes a simple test.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136313 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2011-07-28 00:38:23 +00:00
parent 8050a61914
commit 2bf84c15d2
1 changed files with 98 additions and 10 deletions
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108
lib/Transforms/Utils/InlineFunction.cpp
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@ -250,21 +250,29 @@ namespace {
PHINode *InnerSelectorPHI;
SmallVector<Value*, 8> UnwindDestPHIValues;
public:
InvokeInliningInfo(InvokeInst *II) :
OuterUnwindDest(II->getUnwindDest()), OuterSelector(0),
InnerUnwindDest(0), InnerExceptionPHI(0), InnerSelectorPHI(0) {
SmallVector<LandingPadInst*, 16> CalleeLPads;
LandingPadInst *CallerLPad;
BasicBlock *SplitLPad;
public:
InvokeInliningInfo(InvokeInst *II)
: OuterUnwindDest(II->getUnwindDest()), OuterSelector(0),
InnerUnwindDest(0), InnerExceptionPHI(0), InnerSelectorPHI(0),
CallerLPad(0), SplitLPad(0) {
// If there are PHI nodes in the unwind destination block, we
// need to keep track of which values came into them from the
// invoke before removing the edge from this block.
llvm::BasicBlock *invokeBB = II->getParent();
for (BasicBlock::iterator I = OuterUnwindDest->begin();
isa<PHINode>(I); ++I) {
BasicBlock::iterator I = OuterUnwindDest->begin();
for (; isa<PHINode>(I); ++I) {
// Save the value to use for this edge.
PHINode *phi = cast<PHINode>(I);
UnwindDestPHIValues.push_back(phi->getIncomingValueForBlock(invokeBB));
}
// FIXME: With the new EH, this if/dyn_cast should be a 'cast'.
if (LandingPadInst *LPI = dyn_cast<LandingPadInst>(I))
CallerLPad = LPI;
}
/// The outer unwind destination is the target of unwind edges
@ -281,15 +289,39 @@ namespace {
BasicBlock *getInnerUnwindDest();
void addCalleeLandingPad(LandingPadInst *LPI) {
CalleeLPads.push_back(LPI);
}
LandingPadInst *getLandingPadInst() const { return CallerLPad; }
BasicBlock *getSplitLandingPad() {
if (SplitLPad) return SplitLPad;
assert(CallerLPad && "Trying to split a block that isn't a landing pad!");
BasicBlock::iterator I = CallerLPad; ++I;
SplitLPad = CallerLPad->getParent()->splitBasicBlock(I, "split.lpad");
return SplitLPad;
}
bool forwardEHResume(CallInst *call, BasicBlock *src);
/// Add incoming-PHI values to the unwind destination block for
/// the given basic block, using the values for the original
/// invoke's source block.
/// forwardResume - Forward the 'resume' instruction to the caller's landing
/// pad block. When the landing pad block has only one predecessor, this is
/// a simple branch. When there is more than one predecessor, we need to
/// split the landing pad block after the landingpad instruction and jump
/// to there.
void forwardResume(ResumeInst *RI);
/// mergeLandingPadClauses - Visit all of the landing pad instructions which
/// supply the value for the ResumeInst, and merge the clauses from the new
/// destination (the caller's landing pad).
void mergeLandingPadClauses(ResumeInst *RI);
/// addIncomingPHIValuesFor - Add incoming-PHI values to the unwind
/// destination block for the given basic block, using the values for the
/// original invoke's source block.
void addIncomingPHIValuesFor(BasicBlock *BB) const {
addIncomingPHIValuesForInto(BB, OuterUnwindDest);
}
void addIncomingPHIValuesForInto(BasicBlock *src, BasicBlock *dest) const {
BasicBlock::iterator I = dest->begin();
for (unsigned i = 0, e = UnwindDestPHIValues.size(); i != e; ++i, ++I) {
@ -404,6 +436,51 @@ bool InvokeInliningInfo::forwardEHResume(CallInst *call, BasicBlock *src) {
return true;
}
/// mergeLandingPadClauses - Visit all of the landing pad instructions merge the
/// clauses from the new destination (the caller's landing pad).
void InvokeInliningInfo::mergeLandingPadClauses(ResumeInst *RI) {
for (SmallVectorImpl<LandingPadInst*>::iterator
I = CalleeLPads.begin(), E = CalleeLPads.end(); I != E; ++I)
for (unsigned i = 0, e = CallerLPad->getNumClauses(); i != e; ++i)
(*I)->addClause(CallerLPad->getClauseType(i),
CallerLPad->getClauseValue(i));
}
/// forwardResume - Forward the 'resume' instruction to the caller's landing pad
/// block. When the landing pad block has only one predecessor, this is a simple
/// branch. When there is more than one predecessor, we need to split the
/// landing pad block after the landingpad instruction and jump to there.
void InvokeInliningInfo::forwardResume(ResumeInst *RI) {
BasicBlock *LPadBB = CallerLPad->getParent();
Value *ResumeOp = RI->getOperand(0);
if (!LPadBB->getSinglePredecessor()) {
// There are multiple predecessors to this landing pad block. Split this
// landing pad block and jump to the new BB.
BasicBlock *SplitLPad = getSplitLandingPad();
BranchInst::Create(SplitLPad, RI->getParent());
if (CallerLPad->hasOneUse() && isa<PHINode>(CallerLPad->use_back())) {
PHINode *PN = cast<PHINode>(CallerLPad->use_back());
PN->addIncoming(ResumeOp, RI->getParent());
} else {
PHINode *PN = PHINode::Create(ResumeOp->getType(), 0, "lpad.phi",
&SplitLPad->front());
CallerLPad->replaceAllUsesWith(PN);
PN->addIncoming(ResumeOp, RI->getParent());
PN->addIncoming(CallerLPad, LPadBB);
}
RI->eraseFromParent();
return;
}
BranchInst::Create(LPadBB, RI->getParent());
CallerLPad->replaceAllUsesWith(ResumeOp);
CallerLPad->eraseFromParent();
RI->eraseFromParent();
}
/// [LIBUNWIND] Check whether this selector is "only cleanups":
/// call i32 @llvm.eh.selector(blah, blah, i32 0)
static bool isCleanupOnlySelector(EHSelectorInst *selector) {
@ -423,6 +500,12 @@ static bool HandleCallsInBlockInlinedThroughInvoke(BasicBlock *BB,
InvokeInliningInfo &Invoke) {
for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) {
Instruction *I = BBI++;
// Collect the callee's landingpad instructions.
if (LandingPadInst *LPI = dyn_cast<LandingPadInst>(I)) {
Invoke.addCalleeLandingPad(LPI);
continue;
}
// We only need to check for function calls: inlined invoke
// instructions require no special handling.
@ -557,6 +640,11 @@ static void HandleInlinedInvoke(InvokeInst *II, BasicBlock *FirstNewBlock,
// there is now a new entry in them.
Invoke.addIncomingPHIValuesFor(BB);
}
if (ResumeInst *RI = dyn_cast<ResumeInst>(BB->getTerminator())) {
Invoke.mergeLandingPadClauses(RI);
Invoke.forwardResume(RI);
}
}
// Now that everything is happy, we have one final detail. The PHI nodes in