+ if (Cond) { // Constant fold to uncond branch!
+ SwitchInst::ConstCaseIt Case = SI->findCaseValue(Cond);
+ BasicBlock *Dest = const_cast<BasicBlock*>(Case.getCaseSuccessor());
+ VMap[OldTI] = BranchInst::Create(Dest, NewBB);
+ ToClone.push_back(Dest);
+ TerminatorDone = true;
+ }
+ }
+
+ if (!TerminatorDone) {
+ Instruction *NewInst = OldTI->clone();
+ if (OldTI->hasName())
+ NewInst->setName(OldTI->getName()+NameSuffix);
+ NewBB->getInstList().push_back(NewInst);
+ VMap[OldTI] = NewInst; // Add instruction map to value.
+
+ if (CodeInfo)
+ if (auto CS = ImmutableCallSite(OldTI))
+ if (CS.hasOperandBundles())
+ CodeInfo->OperandBundleCallSites.push_back(NewInst);
+
+ // Recursively clone any reachable successor blocks.
+ const TerminatorInst *TI = BB->getTerminator();
+ for (const BasicBlock *Succ : TI->successors())
+ ToClone.push_back(Succ);
+ }
+
+ if (CodeInfo) {
+ CodeInfo->ContainsCalls |= hasCalls;
+ CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
+ CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
+ BB != &BB->getParent()->front();
+ }
+}
+
+/// This works like CloneAndPruneFunctionInto, except that it does not clone the
+/// entire function. Instead it starts at an instruction provided by the caller
+/// and copies (and prunes) only the code reachable from that instruction.
+void llvm::CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
+ const Instruction *StartingInst,
+ ValueToValueMapTy &VMap,
+ bool ModuleLevelChanges,
+ SmallVectorImpl<ReturnInst *> &Returns,
+ const char *NameSuffix,
+ ClonedCodeInfo *CodeInfo) {
+ assert(NameSuffix && "NameSuffix cannot be null!");
+
+ ValueMapTypeRemapper *TypeMapper = nullptr;
+ ValueMaterializer *Materializer = nullptr;
+
+#ifndef NDEBUG
+ // If the cloning starts at the beginning of the function, verify that
+ // the function arguments are mapped.
+ if (!StartingInst)
+ for (const Argument &II : OldFunc->args())
+ assert(VMap.count(&II) && "No mapping from source argument specified!");
+#endif
+
+ PruningFunctionCloner PFC(NewFunc, OldFunc, VMap, ModuleLevelChanges,
+ NameSuffix, CodeInfo);
+ const BasicBlock *StartingBB;
+ if (StartingInst)
+ StartingBB = StartingInst->getParent();
+ else {
+ StartingBB = &OldFunc->getEntryBlock();
+ StartingInst = &StartingBB->front();
+ }
+
+ // Clone the entry block, and anything recursively reachable from it.
+ std::vector<const BasicBlock*> CloneWorklist;
+ PFC.CloneBlock(StartingBB, StartingInst->getIterator(), CloneWorklist);
+ while (!CloneWorklist.empty()) {
+ const BasicBlock *BB = CloneWorklist.back();
+ CloneWorklist.pop_back();
+ PFC.CloneBlock(BB, BB->begin(), CloneWorklist);
+ }
+
+ // Loop over all of the basic blocks in the old function. If the block was
+ // reachable, we have cloned it and the old block is now in the value map:
+ // insert it into the new function in the right order. If not, ignore it.
+ //
+ // Defer PHI resolution until rest of function is resolved.
+ SmallVector<const PHINode*, 16> PHIToResolve;
+ for (const BasicBlock &BI : *OldFunc) {
+ Value *V = VMap[&BI];
+ BasicBlock *NewBB = cast_or_null<BasicBlock>(V);
+ if (!NewBB) continue; // Dead block.
+
+ // Add the new block to the new function.
+ NewFunc->getBasicBlockList().push_back(NewBB);
+
+ // Handle PHI nodes specially, as we have to remove references to dead
+ // blocks.
+ for (BasicBlock::const_iterator I = BI.begin(), E = BI.end(); I != E; ++I) {
+ // PHI nodes may have been remapped to non-PHI nodes by the caller or
+ // during the cloning process.
+ if (const PHINode *PN = dyn_cast<PHINode>(I)) {
+ if (isa<PHINode>(VMap[PN]))
+ PHIToResolve.push_back(PN);
+ else
+ break;
+ } else {
+ break;
+ }
+ }
+
+ // Finally, remap the terminator instructions, as those can't be remapped
+ // until all BBs are mapped.
+ RemapInstruction(NewBB->getTerminator(), VMap,
+ ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
+ TypeMapper, Materializer);
+ }
+
+ // Defer PHI resolution until rest of function is resolved, PHI resolution
+ // requires the CFG to be up-to-date.
+ for (unsigned phino = 0, e = PHIToResolve.size(); phino != e; ) {
+ const PHINode *OPN = PHIToResolve[phino];
+ unsigned NumPreds = OPN->getNumIncomingValues();
+ const BasicBlock *OldBB = OPN->getParent();
+ BasicBlock *NewBB = cast<BasicBlock>(VMap[OldBB]);
+
+ // Map operands for blocks that are live and remove operands for blocks
+ // that are dead.
+ for (; phino != PHIToResolve.size() &&
+ PHIToResolve[phino]->getParent() == OldBB; ++phino) {
+ OPN = PHIToResolve[phino];
+ PHINode *PN = cast<PHINode>(VMap[OPN]);
+ for (unsigned pred = 0, e = NumPreds; pred != e; ++pred) {
+ Value *V = VMap[PN->getIncomingBlock(pred)];
+ if (BasicBlock *MappedBlock = cast_or_null<BasicBlock>(V)) {
+ Value *InVal = MapValue(PN->getIncomingValue(pred),
+ VMap,
+ ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
+ assert(InVal && "Unknown input value?");
+ PN->setIncomingValue(pred, InVal);
+ PN->setIncomingBlock(pred, MappedBlock);
+ } else {
+ PN->removeIncomingValue(pred, false);
+ --pred, --e; // Revisit the next entry.
+ }
+ }
+ }
+
+ // The loop above has removed PHI entries for those blocks that are dead
+ // and has updated others. However, if a block is live (i.e. copied over)
+ // but its terminator has been changed to not go to this block, then our
+ // phi nodes will have invalid entries. Update the PHI nodes in this
+ // case.
+ PHINode *PN = cast<PHINode>(NewBB->begin());
+ NumPreds = std::distance(pred_begin(NewBB), pred_end(NewBB));
+ if (NumPreds != PN->getNumIncomingValues()) {
+ assert(NumPreds < PN->getNumIncomingValues());
+ // Count how many times each predecessor comes to this block.
+ std::map<BasicBlock*, unsigned> PredCount;
+ for (pred_iterator PI = pred_begin(NewBB), E = pred_end(NewBB);
+ PI != E; ++PI)
+ --PredCount[*PI];
+
+ // Figure out how many entries to remove from each PHI.
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
+ ++PredCount[PN->getIncomingBlock(i)];
+
+ // At this point, the excess predecessor entries are positive in the
+ // map. Loop over all of the PHIs and remove excess predecessor
+ // entries.
+ BasicBlock::iterator I = NewBB->begin();
+ for (; (PN = dyn_cast<PHINode>(I)); ++I) {
+ for (std::map<BasicBlock*, unsigned>::iterator PCI =PredCount.begin(),
+ E = PredCount.end(); PCI != E; ++PCI) {
+ BasicBlock *Pred = PCI->first;
+ for (unsigned NumToRemove = PCI->second; NumToRemove; --NumToRemove)
+ PN->removeIncomingValue(Pred, false);
+ }
+ }
+ }
+
+ // If the loops above have made these phi nodes have 0 or 1 operand,
+ // replace them with undef or the input value. We must do this for
+ // correctness, because 0-operand phis are not valid.
+ PN = cast<PHINode>(NewBB->begin());
+ if (PN->getNumIncomingValues() == 0) {
+ BasicBlock::iterator I = NewBB->begin();
+ BasicBlock::const_iterator OldI = OldBB->begin();
+ while ((PN = dyn_cast<PHINode>(I++))) {
+ Value *NV = UndefValue::get(PN->getType());
+ PN->replaceAllUsesWith(NV);
+ assert(VMap[&*OldI] == PN && "VMap mismatch");
+ VMap[&*OldI] = NV;
+ PN->eraseFromParent();
+ ++OldI;
+ }
+ }
+ }
+
+ // Make a second pass over the PHINodes now that all of them have been
+ // remapped into the new function, simplifying the PHINode and performing any
+ // recursive simplifications exposed. This will transparently update the
+ // WeakVH in the VMap. Notably, we rely on that so that if we coalesce
+ // two PHINodes, the iteration over the old PHIs remains valid, and the
+ // mapping will just map us to the new node (which may not even be a PHI
+ // node).
+ for (unsigned Idx = 0, Size = PHIToResolve.size(); Idx != Size; ++Idx)
+ if (PHINode *PN = dyn_cast<PHINode>(VMap[PHIToResolve[Idx]]))
+ recursivelySimplifyInstruction(PN);
+
+ // Now that the inlined function body has been fully constructed, go through
+ // and zap unconditional fall-through branches. This happens all the time when
+ // specializing code: code specialization turns conditional branches into
+ // uncond branches, and this code folds them.
+ Function::iterator Begin = cast<BasicBlock>(VMap[StartingBB])->getIterator();
+ Function::iterator I = Begin;
+ while (I != NewFunc->end()) {
+ // Check if this block has become dead during inlining or other
+ // simplifications. Note that the first block will appear dead, as it has
+ // not yet been wired up properly.
+ if (I != Begin && (pred_begin(&*I) == pred_end(&*I) ||
+ I->getSinglePredecessor() == &*I)) {
+ BasicBlock *DeadBB = &*I++;
+ DeleteDeadBlock(DeadBB);
+ continue;
+ }
+
+ // We need to simplify conditional branches and switches with a constant
+ // operand. We try to prune these out when cloning, but if the
+ // simplification required looking through PHI nodes, those are only
+ // available after forming the full basic block. That may leave some here,
+ // and we still want to prune the dead code as early as possible.
+ ConstantFoldTerminator(&*I);
+
+ BranchInst *BI = dyn_cast<BranchInst>(I->getTerminator());
+ if (!BI || BI->isConditional()) { ++I; continue; }
+
+ BasicBlock *Dest = BI->getSuccessor(0);
+ if (!Dest->getSinglePredecessor()) {
+ ++I; continue;
+ }
+
+ // We shouldn't be able to get single-entry PHI nodes here, as instsimplify
+ // above should have zapped all of them..
+ assert(!isa<PHINode>(Dest->begin()));
+
+ // We know all single-entry PHI nodes in the inlined function have been
+ // removed, so we just need to splice the blocks.
+ BI->eraseFromParent();
+
+ // Make all PHI nodes that referred to Dest now refer to I as their source.
+ Dest->replaceAllUsesWith(&*I);
+
+ // Move all the instructions in the succ to the pred.
+ I->getInstList().splice(I->end(), Dest->getInstList());
+
+ // Remove the dest block.
+ Dest->eraseFromParent();
+
+ // Do not increment I, iteratively merge all things this block branches to.
+ }
+
+ // Make a final pass over the basic blocks from the old function to gather
+ // any return instructions which survived folding. We have to do this here
+ // because we can iteratively remove and merge returns above.
+ for (Function::iterator I = cast<BasicBlock>(VMap[StartingBB])->getIterator(),
+ E = NewFunc->end();
+ I != E; ++I)
+ if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator()))
+ Returns.push_back(RI);
+}
+
+
+/// This works exactly like CloneFunctionInto,
+/// except that it does some simple constant prop and DCE on the fly. The
+/// effect of this is to copy significantly less code in cases where (for
+/// example) a function call with constant arguments is inlined, and those
+/// constant arguments cause a significant amount of code in the callee to be
+/// dead. Since this doesn't produce an exact copy of the input, it can't be
+/// used for things like CloneFunction or CloneModule.
+void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
+ ValueToValueMapTy &VMap,
+ bool ModuleLevelChanges,
+ SmallVectorImpl<ReturnInst*> &Returns,
+ const char *NameSuffix,
+ ClonedCodeInfo *CodeInfo,
+ Instruction *TheCall) {
+ CloneAndPruneIntoFromInst(NewFunc, OldFunc, &OldFunc->front().front(), VMap,
+ ModuleLevelChanges, Returns, NameSuffix, CodeInfo);
+}
+
+/// \brief Remaps instructions in \p Blocks using the mapping in \p VMap.
+void llvm::remapInstructionsInBlocks(
+ const SmallVectorImpl<BasicBlock *> &Blocks, ValueToValueMapTy &VMap) {
+ // Rewrite the code to refer to itself.
+ for (auto *BB : Blocks)
+ for (auto &Inst : *BB)
+ RemapInstruction(&Inst, VMap,
+ RF_NoModuleLevelChanges | RF_IgnoreMissingEntries);
+}
+
+/// \brief Clones a loop \p OrigLoop. Returns the loop and the blocks in \p
+/// Blocks.
+///
+/// Updates LoopInfo and DominatorTree assuming the loop is dominated by block
+/// \p LoopDomBB. Insert the new blocks before block specified in \p Before.
+Loop *llvm::cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB,
+ Loop *OrigLoop, ValueToValueMapTy &VMap,
+ const Twine &NameSuffix, LoopInfo *LI,
+ DominatorTree *DT,
+ SmallVectorImpl<BasicBlock *> &Blocks) {
+ Function *F = OrigLoop->getHeader()->getParent();
+ Loop *ParentLoop = OrigLoop->getParentLoop();
+
+ Loop *NewLoop = new Loop();
+ if (ParentLoop)
+ ParentLoop->addChildLoop(NewLoop);
+ else
+ LI->addTopLevelLoop(NewLoop);
+
+ BasicBlock *OrigPH = OrigLoop->getLoopPreheader();
+ assert(OrigPH && "No preheader");
+ BasicBlock *NewPH = CloneBasicBlock(OrigPH, VMap, NameSuffix, F);
+ // To rename the loop PHIs.
+ VMap[OrigPH] = NewPH;
+ Blocks.push_back(NewPH);
+
+ // Update LoopInfo.
+ if (ParentLoop)
+ ParentLoop->addBasicBlockToLoop(NewPH, *LI);
+
+ // Update DominatorTree.
+ DT->addNewBlock(NewPH, LoopDomBB);
+
+ for (BasicBlock *BB : OrigLoop->getBlocks()) {
+ BasicBlock *NewBB = CloneBasicBlock(BB, VMap, NameSuffix, F);
+ VMap[BB] = NewBB;
+
+ // Update LoopInfo.
+ NewLoop->addBasicBlockToLoop(NewBB, *LI);
+
+ // Update DominatorTree.
+ BasicBlock *IDomBB = DT->getNode(BB)->getIDom()->getBlock();
+ DT->addNewBlock(NewBB, cast<BasicBlock>(VMap[IDomBB]));
+
+ Blocks.push_back(NewBB);
+ }
+
+ // Move them physically from the end of the block list.
+ F->getBasicBlockList().splice(Before->getIterator(), F->getBasicBlockList(),
+ NewPH);
+ F->getBasicBlockList().splice(Before->getIterator(), F->getBasicBlockList(),
+ NewLoop->getHeader()->getIterator(), F->end());