#include "llvm/IR/BasicBlock.h"
#include "SymbolTableListTraitsImpl.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/LeakDetector.h"
#include "llvm/IR/Type.h"
#include <algorithm>
using namespace llvm;
ValueSymbolTable *BasicBlock::getValueSymbolTable() {
if (Function *F = getParent())
return &F->getValueSymbolTable();
return nullptr;
}
const DataLayout *BasicBlock::getDataLayout() const {
return getParent()->getDataLayout();
}
LLVMContext &BasicBlock::getContext() const {
return getType()->getContext();
}
template class llvm::SymbolTableListTraits<Instruction, BasicBlock>;
BasicBlock::BasicBlock(LLVMContext &C, const Twine &Name, Function *NewParent,
BasicBlock *InsertBefore)
: Value(Type::getLabelTy(C), Value::BasicBlockVal), Parent(nullptr) {
LeakDetector::addGarbageObject(this);
if (NewParent)
insertInto(NewParent, InsertBefore);
else
assert(!InsertBefore &&
"Cannot insert block before another block with no function!");
setName(Name);
}
void BasicBlock::insertInto(Function *NewParent, BasicBlock *InsertBefore) {
assert(NewParent && "Expected a parent");
assert(!Parent && "Already has a parent");
if (InsertBefore)
NewParent->getBasicBlockList().insert(InsertBefore, this);
else
NewParent->getBasicBlockList().push_back(this);
}
BasicBlock::~BasicBlock() {
if (hasAddressTaken()) {
assert(!use_empty() && "There should be at least one blockaddress!");
Constant *Replacement =
ConstantInt::get(llvm::Type::getInt32Ty(getContext()), 1);
while (!use_empty()) {
BlockAddress *BA = cast<BlockAddress>(user_back());
BA->replaceAllUsesWith(ConstantExpr::getIntToPtr(Replacement,
BA->getType()));
BA->destroyConstant();
}
}
assert(getParent() == nullptr && "BasicBlock still linked into the program!");
dropAllReferences();
InstList.clear();
}
void BasicBlock::setParent(Function *parent) {
if (getParent())
LeakDetector::addGarbageObject(this);
InstList.setSymTabObject(&Parent, parent);
if (getParent())
LeakDetector::removeGarbageObject(this);
}
void BasicBlock::removeFromParent() {
getParent()->getBasicBlockList().remove(this);
}
void BasicBlock::eraseFromParent() {
getParent()->getBasicBlockList().erase(this);
}
void BasicBlock::moveBefore(BasicBlock *MovePos) {
MovePos->getParent()->getBasicBlockList().splice(MovePos,
getParent()->getBasicBlockList(), this);
}
void BasicBlock::moveAfter(BasicBlock *MovePos) {
Function::iterator I = MovePos;
MovePos->getParent()->getBasicBlockList().splice(++I,
getParent()->getBasicBlockList(), this);
}
TerminatorInst *BasicBlock::getTerminator() {
if (InstList.empty()) return nullptr;
return dyn_cast<TerminatorInst>(&InstList.back());
}
const TerminatorInst *BasicBlock::getTerminator() const {
if (InstList.empty()) return nullptr;
return dyn_cast<TerminatorInst>(&InstList.back());
}
CallInst *BasicBlock::getTerminatingMustTailCall() {
if (InstList.empty())
return nullptr;
ReturnInst *RI = dyn_cast<ReturnInst>(&InstList.back());
if (!RI || RI == &InstList.front())
return nullptr;
Instruction *Prev = RI->getPrevNode();
if (!Prev)
return nullptr;
if (Value *RV = RI->getReturnValue()) {
if (RV != Prev)
return nullptr;
if (auto *BI = dyn_cast<BitCastInst>(Prev)) {
RV = BI->getOperand(0);
Prev = BI->getPrevNode();
if (!Prev || RV != Prev)
return nullptr;
}
}
if (auto *CI = dyn_cast<CallInst>(Prev)) {
if (CI->isMustTailCall())
return CI;
}
return nullptr;
}
Instruction* BasicBlock::getFirstNonPHI() {
BasicBlock::iterator i = begin();
while (isa<PHINode>(i)) ++i;
return &*i;
}
Instruction* BasicBlock::getFirstNonPHIOrDbg() {
BasicBlock::iterator i = begin();
while (isa<PHINode>(i) || isa<DbgInfoIntrinsic>(i)) ++i;
return &*i;
}
Instruction* BasicBlock::getFirstNonPHIOrDbgOrLifetime() {
BasicBlock::iterator i = begin();
for (;; ++i) {
if (isa<PHINode>(i) || isa<DbgInfoIntrinsic>(i))
continue;
const IntrinsicInst *II = dyn_cast<IntrinsicInst>(i);
if (!II)
break;
if (II->getIntrinsicID() != Intrinsic::lifetime_start &&
II->getIntrinsicID() != Intrinsic::lifetime_end)
break;
}
return &*i;
}
BasicBlock::iterator BasicBlock::getFirstInsertionPt() {
iterator InsertPt = getFirstNonPHI();
if (isa<LandingPadInst>(InsertPt)) ++InsertPt;
return InsertPt;
}
void BasicBlock::dropAllReferences() {
for(iterator I = begin(), E = end(); I != E; ++I)
I->dropAllReferences();
}
BasicBlock *BasicBlock::getSinglePredecessor() {
pred_iterator PI = pred_begin(this), E = pred_end(this);
if (PI == E) return nullptr; BasicBlock *ThePred = *PI;
++PI;
return (PI == E) ? ThePred : nullptr ;
}
BasicBlock *BasicBlock::getUniquePredecessor() {
pred_iterator PI = pred_begin(this), E = pred_end(this);
if (PI == E) return nullptr; BasicBlock *PredBB = *PI;
++PI;
for (;PI != E; ++PI) {
if (*PI != PredBB)
return nullptr;
}
return PredBB;
}
void BasicBlock::removePredecessor(BasicBlock *Pred,
bool DontDeleteUselessPHIs) {
assert((hasNUsesOrMore(16)|| find(pred_begin(this), pred_end(this), Pred) != pred_end(this)) &&
"removePredecessor: BB is not a predecessor!");
if (InstList.empty()) return;
PHINode *APN = dyn_cast<PHINode>(&front());
if (!APN) return;
unsigned max_idx = APN->getNumIncomingValues();
assert(max_idx != 0 && "PHI Node in block with 0 predecessors!?!?!");
if (max_idx == 2) {
BasicBlock *Other = APN->getIncomingBlock(APN->getIncomingBlock(0) == Pred);
if (this == Other) max_idx = 3;
}
if (max_idx <= 2 && !DontDeleteUselessPHIs) {
while (PHINode *PN = dyn_cast<PHINode>(&front())) {
PN->removeIncomingValue(Pred, !DontDeleteUselessPHIs);
if (max_idx == 2) {
if (PN->getIncomingValue(0) != PN)
PN->replaceAllUsesWith(PN->getIncomingValue(0));
else
PN->replaceAllUsesWith(UndefValue::get(PN->getType()));
getInstList().pop_front(); }
}
} else {
PHINode *PN;
for (iterator II = begin(); (PN = dyn_cast<PHINode>(II)); ) {
++II;
PN->removeIncomingValue(Pred, false);
Value* PNV = nullptr;
if (!DontDeleteUselessPHIs && (PNV = PN->hasConstantValue()))
if (PNV != PN) {
PN->replaceAllUsesWith(PNV);
PN->eraseFromParent();
}
}
}
}
BasicBlock *BasicBlock::splitBasicBlock(iterator I, const Twine &BBName) {
assert(getTerminator() && "Can't use splitBasicBlock on degenerate BB!");
assert(I != InstList.end() &&
"Trying to get me to create degenerate basic block!");
BasicBlock *InsertBefore = std::next(Function::iterator(this))
.getNodePtrUnchecked();
BasicBlock *New = BasicBlock::Create(getContext(), BBName,
getParent(), InsertBefore);
New->getInstList().splice(New->end(), this->getInstList(), I, end());
BranchInst::Create(New, this);
for (succ_iterator I = succ_begin(New), E = succ_end(New); I != E; ++I) {
BasicBlock *Successor = *I;
PHINode *PN;
for (BasicBlock::iterator II = Successor->begin();
(PN = dyn_cast<PHINode>(II)); ++II) {
int IDX = PN->getBasicBlockIndex(this);
while (IDX != -1) {
PN->setIncomingBlock((unsigned)IDX, New);
IDX = PN->getBasicBlockIndex(this);
}
}
}
return New;
}
void BasicBlock::replaceSuccessorsPhiUsesWith(BasicBlock *New) {
TerminatorInst *TI = getTerminator();
if (!TI)
return;
for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
BasicBlock *Succ = TI->getSuccessor(i);
for (iterator II = Succ->begin(), IE = Succ->end(); II != IE; ++II) {
PHINode *PN = dyn_cast<PHINode>(II);
if (!PN)
break;
int i;
while ((i = PN->getBasicBlockIndex(this)) >= 0)
PN->setIncomingBlock(i, New);
}
}
}
bool BasicBlock::isLandingPad() const {
return isa<LandingPadInst>(getFirstNonPHI());
}
LandingPadInst *BasicBlock::getLandingPadInst() {
return dyn_cast<LandingPadInst>(getFirstNonPHI());
}
const LandingPadInst *BasicBlock::getLandingPadInst() const {
return dyn_cast<LandingPadInst>(getFirstNonPHI());
}