#include "llvm/IR/Dominators.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/GenericDomTreeConstruction.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
using namespace llvm;
#ifdef XDEBUG
static bool VerifyDomInfo = true;
#else
static bool VerifyDomInfo = false;
#endif
static cl::opt<bool,true>
VerifyDomInfoX("verify-dom-info", cl::location(VerifyDomInfo),
cl::desc("Verify dominator info (time consuming)"));
bool BasicBlockEdge::isSingleEdge() const {
const TerminatorInst *TI = Start->getTerminator();
unsigned NumEdgesToEnd = 0;
for (unsigned int i = 0, n = TI->getNumSuccessors(); i < n; ++i) {
if (TI->getSuccessor(i) == End)
++NumEdgesToEnd;
if (NumEdgesToEnd >= 2)
return false;
}
assert(NumEdgesToEnd == 1);
return true;
}
template class llvm::DomTreeNodeBase<BasicBlock>;
template class llvm::DominatorTreeBase<BasicBlock>;
template void llvm::Calculate<Function, BasicBlock *>(
DominatorTreeBase<GraphTraits<BasicBlock *>::NodeType> &DT, Function &F);
template void llvm::Calculate<Function, Inverse<BasicBlock *>>(
DominatorTreeBase<GraphTraits<Inverse<BasicBlock *>>::NodeType> &DT,
Function &F);
bool DominatorTree::dominates(const Instruction *Def,
const Instruction *User) const {
const BasicBlock *UseBB = User->getParent();
const BasicBlock *DefBB = Def->getParent();
if (!isReachableFromEntry(UseBB))
return true;
if (!isReachableFromEntry(DefBB))
return false;
if (Def == User)
return false;
if (isa<InvokeInst>(Def) || isa<CatchPadInst>(Def) || isa<PHINode>(User))
return dominates(Def, UseBB);
if (DefBB != UseBB)
return dominates(DefBB, UseBB);
BasicBlock::const_iterator I = DefBB->begin();
for (; &*I != Def && &*I != User; ++I)
;
return &*I == Def;
}
bool DominatorTree::dominates(const Instruction *Def,
const BasicBlock *UseBB) const {
const BasicBlock *DefBB = Def->getParent();
if (!isReachableFromEntry(UseBB))
return true;
if (!isReachableFromEntry(DefBB))
return false;
if (DefBB == UseBB)
return false;
if (const auto *II = dyn_cast<InvokeInst>(Def)) {
BasicBlock *NormalDest = II->getNormalDest();
BasicBlockEdge E(DefBB, NormalDest);
return dominates(E, UseBB);
}
if (const auto *CPI = dyn_cast<CatchPadInst>(Def)) {
BasicBlock *NormalDest = CPI->getNormalDest();
BasicBlockEdge E(DefBB, NormalDest);
return dominates(E, UseBB);
}
return dominates(DefBB, UseBB);
}
bool DominatorTree::dominates(const BasicBlockEdge &BBE,
const BasicBlock *UseBB) const {
assert(BBE.isSingleEdge() &&
"This function is not efficient in handling multiple edges");
const BasicBlock *Start = BBE.getStart();
const BasicBlock *End = BBE.getEnd();
if (!dominates(End, UseBB))
return false;
if (End->getSinglePredecessor())
return true;
for (const_pred_iterator PI = pred_begin(End), E = pred_end(End);
PI != E; ++PI) {
const BasicBlock *BB = *PI;
if (BB == Start)
continue;
if (!dominates(End, BB))
return false;
}
return true;
}
bool DominatorTree::dominates(const BasicBlockEdge &BBE, const Use &U) const {
assert(BBE.isSingleEdge() &&
"This function is not efficient in handling multiple edges");
Instruction *UserInst = cast<Instruction>(U.getUser());
PHINode *PN = dyn_cast<PHINode>(UserInst);
if (PN && PN->getParent() == BBE.getEnd() &&
PN->getIncomingBlock(U) == BBE.getStart())
return true;
const BasicBlock *UseBB;
if (PN)
UseBB = PN->getIncomingBlock(U);
else
UseBB = UserInst->getParent();
return dominates(BBE, UseBB);
}
bool DominatorTree::dominates(const Instruction *Def, const Use &U) const {
Instruction *UserInst = cast<Instruction>(U.getUser());
const BasicBlock *DefBB = Def->getParent();
const BasicBlock *UseBB;
if (PHINode *PN = dyn_cast<PHINode>(UserInst))
UseBB = PN->getIncomingBlock(U);
else
UseBB = UserInst->getParent();
if (!isReachableFromEntry(UseBB))
return true;
if (!isReachableFromEntry(DefBB))
return false;
if (const InvokeInst *II = dyn_cast<InvokeInst>(Def)) {
BasicBlock *NormalDest = II->getNormalDest();
BasicBlockEdge E(DefBB, NormalDest);
return dominates(E, U);
}
if (const auto *CPI = dyn_cast<CatchPadInst>(Def)) {
BasicBlock *NormalDest = CPI->getNormalDest();
BasicBlockEdge E(DefBB, NormalDest);
return dominates(E, U);
}
if (DefBB != UseBB)
return dominates(DefBB, UseBB);
if (isa<PHINode>(UserInst))
return true;
BasicBlock::const_iterator I = DefBB->begin();
for (; &*I != Def && &*I != UserInst; ++I)
;
return &*I != UserInst;
}
bool DominatorTree::isReachableFromEntry(const Use &U) const {
Instruction *I = dyn_cast<Instruction>(U.getUser());
if (!I) return true;
if (PHINode *PN = dyn_cast<PHINode>(I))
return isReachableFromEntry(PN->getIncomingBlock(U));
return isReachableFromEntry(I->getParent());
}
void DominatorTree::verifyDomTree() const {
Function &F = *getRoot()->getParent();
DominatorTree OtherDT;
OtherDT.recalculate(F);
if (compare(OtherDT)) {
errs() << "DominatorTree is not up to date!\nComputed:\n";
print(errs());
errs() << "\nActual:\n";
OtherDT.print(errs());
abort();
}
}
DominatorTree DominatorTreeAnalysis::run(Function &F) {
DominatorTree DT;
DT.recalculate(F);
return DT;
}
char DominatorTreeAnalysis::PassID;
DominatorTreePrinterPass::DominatorTreePrinterPass(raw_ostream &OS) : OS(OS) {}
PreservedAnalyses DominatorTreePrinterPass::run(Function &F,
FunctionAnalysisManager *AM) {
OS << "DominatorTree for function: " << F.getName() << "\n";
AM->getResult<DominatorTreeAnalysis>(F).print(OS);
return PreservedAnalyses::all();
}
PreservedAnalyses DominatorTreeVerifierPass::run(Function &F,
FunctionAnalysisManager *AM) {
AM->getResult<DominatorTreeAnalysis>(F).verifyDomTree();
return PreservedAnalyses::all();
}
char DominatorTreeWrapperPass::ID = 0;
INITIALIZE_PASS(DominatorTreeWrapperPass, "domtree",
"Dominator Tree Construction", true, true)
bool DominatorTreeWrapperPass::runOnFunction(Function &F) {
DT.recalculate(F);
return false;
}
void DominatorTreeWrapperPass::verifyAnalysis() const {
if (VerifyDomInfo)
DT.verifyDomTree();
}
void DominatorTreeWrapperPass::print(raw_ostream &OS, const Module *) const {
DT.print(OS);
}