bool FunctionStaticSlicer::updateRCSC(
PostDominanceFrontier::DomSetType::const_iterator start,
PostDominanceFrontier::DomSetType::const_iterator end) {
bool changed = false;
#ifdef DEBUG_RC
errs() << __func__ << " ============ BEG\n";
#endif
for (; start != end; start++) {
const BasicBlock *BB = *start;
const Instruction &i = BB->back();
InsInfo *ii = getInsInfo(&i);
/* SC = BC \cup ... */
#ifdef DEBUG_SLICING
errs() << "XXXXXXXXXXXXXX " << BB->getName() << " ";
i.print(errs());
errs() << '\n';
#endif
ii->deslice();
/* RC = ... \cup \cup(b \in BC) RB */
for (ValSet::const_iterator II = ii->REF_begin(), EE = ii->REF_end();
II != EE; II++)
if (ii->addRC(*II)) {
changed = true;
#ifdef DEBUG_RC
errs() << " added " << (*II)->getName() << "\n";
#endif
}
}
#ifdef DEBUG_RC
errs() << __func__ << " ============ END: changed=" << changed << "\n";
#endif
return changed;
}
/*
* SC(i)={i| DEF(i) \cap RC(j) \neq \emptyset}
*/
void FunctionStaticSlicer::computeSCi(const Instruction *i, const Instruction *j) {
InsInfo *insInfoi = getInsInfo(i), *insInfoj = getInsInfo(j);
bool isect_nonempty = false;
for (ValSet::const_iterator I = insInfoi->DEF_begin(),
E = insInfoi->DEF_end(); I != E && !isect_nonempty; I++) {
const Pointee &DEFi = *I;
for (ValSet::const_iterator II = insInfoj->RC_begin(),
EE = insInfoj->RC_end(); II != EE; II++) {
if (sameValues(DEFi, *II)) {
isect_nonempty = true;
break;
}
}
}
if (isect_nonempty) {
insInfoi->deslice();
#ifdef DEBUG_SLICING
errs() << "XXXXXXXXXXXXXY ";
i->print(errs());
errs() << '\n';
#endif
}
}
/*
* SC(i)={i| DEF(i) \cap RC(j) \neq \emptyset}
*/
void FunctionStaticSlicer::computeSCi(const Instruction *i, const Instruction *j) {
InsInfo *insInfoi = getInsInfo(i), *insInfoj = getInsInfo(j);
// Intersection between DEF and RC is initially empty
bool isect_nonempty = false;
for (ValSet::const_iterator I = insInfoi->DEF_begin(),
E = insInfoi->DEF_end(); I != E && !isect_nonempty; I++) {
const Pointee &DEFi = *I;
for (ValSet::const_iterator II = insInfoj->RC_begin(),
EE = insInfoj->RC_end(); II != EE; II++) {
if(Helper::checkValid(DEFi, *II))
if (AA->alias(DEFi.first, II->first)) {
DEBUG( errs() << "isect_nonempty " );
DEBUG( DEFi.first->print(errs()) );
DEBUG( errs() << "\n" );
isect_nonempty = true;
break;
}
}
}
if (isect_nonempty) {
insInfoi->deslice();
#ifdef DEBUG_SLICING
errs() << "XXXXXXXXXXXXXY ";
i->print(errs());
errs() << '\n';
#endif
}
}
void FunctionStaticSlicer::clearMem() {
// Clear RC from every instruction other than call or return
// instruction. Call and return instruction will be later
// used in emitToCalls and emitToExits.
for (inst_iterator I = inst_begin(fun), E = inst_end(fun); I != E; I++) {
Instruction *i = &*I;
if( CallInst *CI = dyn_cast<CallInst>(i) )
continue;
if( ReturnInst *RI = dyn_cast<ReturnInst>(i) )
continue;
InsInfo *insInfoi = getInsInfo(&*I);
insInfoi->clearRC();
}
}
/*
* j is predecessor of i
* SC(i)={i| REF(i) \cap RC(j) \neq \emptyset}
* Statement i should be in slice if it uses a relevant variable
*/
void FwdFunctionStaticSlicer::computeSCi(const Instruction *i, const Instruction *j) {
InsInfo *insInfoi = getInsInfo(i), *insInfoj = getInsInfo(j);
#ifdef DEBUG_SLICE
errs() << "\n\ti ==>\t";
i->print(errs());
errs() << "\n\tj ==>\t";
j->print(errs());
#endif
bool isect_nonempty = false;
for (ValSet::const_iterator I = insInfoi->REF_begin(),
E = insInfoi->REF_end(); I != E && !isect_nonempty; I++) {
const Pointee &REFi = *I;
for (ValSet::const_iterator II = insInfoj->RC_begin(),
EE = insInfoj->RC_end(); II != EE; II++) {
if(Helper::checkValid(REFi, *II)) {
#ifdef DEBUG_SLICE
errs() << "\n\t\t";
REFi.first->print(errs());
errs() << "\t\t";
II->first->print(errs());
#endif
if (AA->isMustAlias(REFi.first, II->first)) {
isect_nonempty = true;
break;
}
}
}
}
if (isect_nonempty) {
insInfoi->deslice();
#ifdef DEBUG_SLICING
errs() << "\n\tXXXXXXXXXXXXXY ";
i->print(errs());
errs() << '\n';
#endif
}
}
bool FunctionStaticSlicer::computeBC() {
bool changed = false;
#ifdef DEBUG_BC
errs() << " ====== BEG BC Computation ======\n";
#endif
if (!forward) {
PostDominanceFrontier &PDF = MP->getAnalysis<PostDominanceFrontier>(fun);
for (inst_iterator I = inst_begin(fun), E = inst_end(fun); I != E; I++) {
Instruction *i = &*I;
const InsInfo *ii = getInsInfo(i);
if (ii->isSliced())
continue;
BasicBlock *BB = i->getParent();
#ifdef DEBUG_BC
errs() << " ";
i->print(errs());
errs() << " -> bb=" << BB->getName() << '\n';
#endif
PostDominanceFrontier::const_iterator frontier = PDF.find(BB);
if (frontier == PDF.end())
continue;
changed |= updateRCSC(frontier->second.begin(), frontier->second.end());
}
}
else {
for (inst_iterator I = inst_begin(fun), E = inst_end(fun); I != E; I++) {
Instruction *i = &*I;
if (!isa<BranchInst>(i))
continue;
BranchInst * bi = dyn_cast<BranchInst>(i);
if (bi->isUnconditional()) // skip unconditional inst
continue;
const InsInfo *ii = getInsInfo(i);
if (ii->isSliced())
continue;
unsigned succs = bi->getNumSuccessors();
for (unsigned si = 0; si < succs; si++) {
BasicBlock * BB = bi->getSuccessor(si);
BasicBlock * Pred = BB->getUniquePredecessor();
if (Pred == NULL)
continue;
for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE; BI++) {
InsInfo *bii = getInsInfo(&*BI);
bii->deslice();
for (ValSet::const_iterator VI = bii->DEF_begin(), VE = bii->DEF_end();
VI != VE; VI++) {
if (bii->addRC(*VI)) {
changed = true;
#ifdef DEBUG_RC
errs() << " added ";
printVal(*VI);
errs() << "\n";
#endif
}
}
}
}
}
}
#ifdef DEBUG_BC
errs() << " ====== END BC Computation ======\n";
#endif
return changed;
}