/// DeleteBasicBlock - remove the specified basic block from the program,
/// updating the callgraph to reflect any now-obsolete edges due to calls that
/// exist in the BB.
void PruneEH::DeleteBasicBlock(BasicBlock *BB) {
assert(pred_begin(BB) == pred_end(BB) && "BB is not dead!");
CallGraph &CG = getAnalysis<CallGraph>();
CallGraphNode *CGN = CG[BB->getParent()];
for (BasicBlock::iterator I = BB->end(), E = BB->begin(); I != E; ) {
--I;
if (CallInst *CI = dyn_cast<CallInst>(I)) {
if (Function *Callee = CI->getCalledFunction())
CGN->removeCallEdgeTo(CG[Callee]);
} else if (InvokeInst *II = dyn_cast<InvokeInst>(I)) {
if (Function *Callee = II->getCalledFunction())
CGN->removeCallEdgeTo(CG[Callee]);
}
if (!I->use_empty())
I->replaceAllUsesWith(UndefValue::get(I->getType()));
}
// Get the list of successors of this block.
std::vector<BasicBlock*> Succs(succ_begin(BB), succ_end(BB));
for (unsigned i = 0, e = Succs.size(); i != e; ++i)
Succs[i]->removePredecessor(BB);
BB->eraseFromParent();
}
/// UpdateCallGraphAfterInlining - Once we have cloned code over from a callee
/// into the caller, update the specified callgraph to reflect the changes we
/// made. Note that it's possible that not all code was copied over, so only
/// some edges of the callgraph will be remain.
static void UpdateCallGraphAfterInlining(const Function *Caller,
const Function *Callee,
Function::iterator FirstNewBlock,
DenseMap<const Value*, Value*> &ValueMap,
CallGraph &CG) {
// Update the call graph by deleting the edge from Callee to Caller
CallGraphNode *CalleeNode = CG[Callee];
CallGraphNode *CallerNode = CG[Caller];
CallerNode->removeCallEdgeTo(CalleeNode);
// Since we inlined some uninlined call sites in the callee into the caller,
// add edges from the caller to all of the callees of the callee.
for (CallGraphNode::iterator I = CalleeNode->begin(),
E = CalleeNode->end(); I != E; ++I) {
const Instruction *OrigCall = I->first.getInstruction();
DenseMap<const Value*, Value*>::iterator VMI = ValueMap.find(OrigCall);
// Only copy the edge if the call was inlined!
if (VMI != ValueMap.end() && VMI->second) {
// If the call was inlined, but then constant folded, there is no edge to
// add. Check for this case.
if (Instruction *NewCall = dyn_cast<Instruction>(VMI->second))
CallerNode->addCalledFunction(CallSite::get(NewCall), I->second);
}
}
}
// doFinalization - Remove now-dead linkonce functions at the end of
// processing to avoid breaking the SCC traversal.
bool Inliner::doFinalization(CallGraph &CG) {
std::set<CallGraphNode*> FunctionsToRemove;
// Scan for all of the functions, looking for ones that should now be removed
// from the program. Insert the dead ones in the FunctionsToRemove set.
for (CallGraph::iterator I = CG.begin(), E = CG.end(); I != E; ++I) {
CallGraphNode *CGN = I->second;
if (Function *F = CGN ? CGN->getFunction() : 0) {
// If the only remaining users of the function are dead constants, remove
// them.
F->removeDeadConstantUsers();
if ((F->hasLinkOnceLinkage() || F->hasInternalLinkage()) &&
F->use_empty()) {
// Remove any call graph edges from the function to its callees.
while (!CGN->empty())
CGN->removeCallEdgeTo((CGN->end()-1)->second);
// Remove any edges from the external node to the function's call graph
// node. These edges might have been made irrelegant due to
// optimization of the program.
CG.getExternalCallingNode()->removeAnyCallEdgeTo(CGN);
// Removing the node for callee from the call graph and delete it.
FunctionsToRemove.insert(CGN);
}
}
}
// Now that we know which functions to delete, do so. We didn't want to do
// this inline, because that would invalidate our CallGraph::iterator
// objects. :(
bool Changed = false;
for (std::set<CallGraphNode*>::iterator I = FunctionsToRemove.begin(),
E = FunctionsToRemove.end(); I != E; ++I) {
delete CG.removeFunctionFromModule(*I);
++NumDeleted;
Changed = true;
}
return Changed;
}
// InlineCallIfPossible - If it is possible to inline the specified call site,
// do so and update the CallGraph for this operation.
static bool InlineCallIfPossible(CallSite CS, CallGraph &CG,
const std::set<Function*> &SCCFunctions,
const TargetData &TD) {
Function *Callee = CS.getCalledFunction();
if (!InlineFunction(CS, &CG, &TD)) return false;
// If we inlined the last possible call site to the function, delete the
// function body now.
if (Callee->use_empty() && Callee->hasInternalLinkage() &&
!SCCFunctions.count(Callee)) {
DOUT << " -> Deleting dead function: " << Callee->getName() << "\n";
// Remove any call graph edges from the callee to its callees.
CallGraphNode *CalleeNode = CG[Callee];
while (!CalleeNode->empty())
CalleeNode->removeCallEdgeTo((CalleeNode->end()-1)->second);
// Removing the node for callee from the call graph and delete it.
delete CG.removeFunctionFromModule(CalleeNode);
++NumDeleted;
}
return true;
}
