#include "llvm/Analysis/Dominators.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/Compiler.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SetOperations.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/DominatorInternals.h"
#include "llvm/Instructions.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/CommandLine.h"
#include <algorithm>
using namespace llvm;
#ifdef XDEBUG
bool VerifyDomInfo = true;
#else
bool VerifyDomInfo = false;
#endif
static cl::opt<bool,true>
VerifyDomInfoX("verify-dom-info", cl::location(VerifyDomInfo),
cl::desc("Verify dominator info (time consuming)"));
TEMPLATE_INSTANTIATION(class llvm::DomTreeNodeBase<BasicBlock>);
TEMPLATE_INSTANTIATION(class llvm::DominatorTreeBase<BasicBlock>);
char DominatorTree::ID = 0;
static RegisterPass<DominatorTree>
E("domtree", "Dominator Tree Construction", true, true);
bool DominatorTree::runOnFunction(Function &F) {
DT->recalculate(F);
return false;
}
void DominatorTree::verifyAnalysis() const {
if (!VerifyDomInfo) return;
Function &F = *getRoot()->getParent();
DominatorTree OtherDT;
OtherDT.getBase().recalculate(F);
assert(!compare(OtherDT) && "Invalid DominatorTree info!");
}
void DominatorTree::print(raw_ostream &OS, const Module *) const {
DT->print(OS);
}
bool DominatorTree::dominates(const Instruction *A, const Instruction *B) const{
const BasicBlock *BBA = A->getParent(), *BBB = B->getParent();
if (const InvokeInst *II = dyn_cast<InvokeInst>(A))
BBA = II->getNormalDest();
if (BBA != BBB) return dominates(BBA, BBB);
if (isa<PHINode>(A) && isa<PHINode>(B))
return false;
BasicBlock::const_iterator I = BBA->begin();
for (; &*I != A && &*I != B; ++I)
;
return &*I == A;
}
char DominanceFrontier::ID = 0;
static RegisterPass<DominanceFrontier>
G("domfrontier", "Dominance Frontier Construction", true, true);
void DominanceFrontier::verifyAnalysis() const {
if (!VerifyDomInfo) return;
DominatorTree &DT = getAnalysis<DominatorTree>();
DominanceFrontier OtherDF;
const std::vector<BasicBlock*> &DTRoots = DT.getRoots();
OtherDF.calculate(DT, DT.getNode(DTRoots[0]));
assert(!compare(OtherDF) && "Invalid DominanceFrontier info!");
}
void DominanceFrontier::splitBlock(BasicBlock *NewBB) {
assert(NewBB->getTerminator()->getNumSuccessors() == 1
&& "NewBB should have a single successor!");
BasicBlock *NewBBSucc = NewBB->getTerminator()->getSuccessor(0);
SmallVector<BasicBlock*, 8> PredBlocks;
for (pred_iterator PI = pred_begin(NewBB), PE = pred_end(NewBB);
PI != PE; ++PI)
PredBlocks.push_back(*PI);
if (PredBlocks.empty())
return;
DominanceFrontier::iterator NewBBI = find(NewBB);
if (NewBBI != end()) {
DominanceFrontier::DomSetType NewBBSet = NewBBI->second;
DominanceFrontier::DomSetType NewBBSuccSet;
NewBBSuccSet.insert(NewBBSet.begin(), NewBBSet.end());
addBasicBlock(NewBBSucc, NewBBSuccSet);
}
DominatorTree &DT = getAnalysis<DominatorTree>();
if (DT.dominates(NewBB, NewBBSucc)) {
DominanceFrontier::iterator DFI = find(PredBlocks[0]);
if (DFI != end()) {
DominanceFrontier::DomSetType Set = DFI->second;
for (DominanceFrontier::DomSetType::iterator SetI = Set.begin(),
E = Set.end(); SetI != E;) {
bool DominatesPred = false;
for (pred_iterator PI = pred_begin(*SetI), E = pred_end(*SetI);
PI != E; ++PI)
if (DT.dominates(NewBB, *PI))
DominatesPred = true;
if (!DominatesPred)
Set.erase(SetI++);
else
++SetI;
}
if (NewBBI != end()) {
for (DominanceFrontier::DomSetType::iterator SetI = Set.begin(),
E = Set.end(); SetI != E; ++SetI) {
BasicBlock *SB = *SetI;
addToFrontier(NewBBI, SB);
}
} else
addBasicBlock(NewBB, Set);
}
} else {
DominanceFrontier::DomSetType NewDFSet;
NewDFSet.insert(NewBBSucc);
addBasicBlock(NewBB, NewDFSet);
}
for (Function::iterator FI = NewBB->getParent()->begin(),
FE = NewBB->getParent()->end(); FI != FE; ++FI) {
DominanceFrontier::iterator DFI = find(FI);
if (DFI == end()) continue;
if (!DFI->second.count(NewBBSucc)) continue;
bool BlockDominatesAny = false;
for (SmallVectorImpl<BasicBlock*>::const_iterator BI = PredBlocks.begin(),
BE = PredBlocks.end(); BI != BE; ++BI) {
if (DT.dominates(FI, *BI)) {
BlockDominatesAny = true;
break;
}
}
bool ShouldRemove = true;
if ((BasicBlock*)FI == NewBBSucc || !DT.dominates(FI, NewBBSucc)) {
for (pred_iterator PI = pred_begin(NewBBSucc),
E = pred_end(NewBBSucc); PI != E; ++PI)
if (DT.dominates(FI, *PI)) {
ShouldRemove = false;
break;
}
}
if (ShouldRemove)
removeFromFrontier(DFI, NewBBSucc);
if (BlockDominatesAny && (&*FI == NewBB || !DT.dominates(FI, NewBB)))
addToFrontier(DFI, NewBB);
}
}
namespace {
class DFCalculateWorkObject {
public:
DFCalculateWorkObject(BasicBlock *B, BasicBlock *P,
const DomTreeNode *N,
const DomTreeNode *PN)
: currentBB(B), parentBB(P), Node(N), parentNode(PN) {}
BasicBlock *currentBB;
BasicBlock *parentBB;
const DomTreeNode *Node;
const DomTreeNode *parentNode;
};
}
const DominanceFrontier::DomSetType &
DominanceFrontier::calculate(const DominatorTree &DT,
const DomTreeNode *Node) {
BasicBlock *BB = Node->getBlock();
DomSetType *Result = NULL;
std::vector<DFCalculateWorkObject> workList;
SmallPtrSet<BasicBlock *, 32> visited;
workList.push_back(DFCalculateWorkObject(BB, NULL, Node, NULL));
do {
DFCalculateWorkObject *currentW = &workList.back();
assert (currentW && "Missing work object.");
BasicBlock *currentBB = currentW->currentBB;
BasicBlock *parentBB = currentW->parentBB;
const DomTreeNode *currentNode = currentW->Node;
const DomTreeNode *parentNode = currentW->parentNode;
assert (currentBB && "Invalid work object. Missing current Basic Block");
assert (currentNode && "Invalid work object. Missing current Node");
DomSetType &S = Frontiers[currentBB];
if (visited.count(currentBB) == 0) {
visited.insert(currentBB);
for (succ_iterator SI = succ_begin(currentBB), SE = succ_end(currentBB);
SI != SE; ++SI) {
if (DT[*SI]->getIDom() != currentNode)
S.insert(*SI);
}
}
bool visitChild = false;
for (DomTreeNode::const_iterator NI = currentNode->begin(),
NE = currentNode->end(); NI != NE; ++NI) {
DomTreeNode *IDominee = *NI;
BasicBlock *childBB = IDominee->getBlock();
if (visited.count(childBB) == 0) {
workList.push_back(DFCalculateWorkObject(childBB, currentBB,
IDominee, currentNode));
visitChild = true;
}
}
if (!visitChild) {
if (!parentBB) {
Result = &S;
break;
}
DomSetType::const_iterator CDFI = S.begin(), CDFE = S.end();
DomSetType &parentSet = Frontiers[parentBB];
for (; CDFI != CDFE; ++CDFI) {
if (!DT.properlyDominates(parentNode, DT[*CDFI]))
parentSet.insert(*CDFI);
}
workList.pop_back();
}
} while (!workList.empty());
return *Result;
}
void DominanceFrontierBase::print(raw_ostream &OS, const Module* ) const {
for (const_iterator I = begin(), E = end(); I != E; ++I) {
OS << " DomFrontier for BB ";
if (I->first)
WriteAsOperand(OS, I->first, false);
else
OS << " <<exit node>>";
OS << " is:\t";
const std::set<BasicBlock*> &BBs = I->second;
for (std::set<BasicBlock*>::const_iterator I = BBs.begin(), E = BBs.end();
I != E; ++I) {
OS << ' ';
if (*I)
WriteAsOperand(OS, *I, false);
else
OS << "<<exit node>>";
}
OS << "\n";
}
}