bool AArch64PromoteConstant::insertDefinitions(
Constant *Cst, InsertionPointsPerFunc &InsPtsPerFunc) {
// We will create one global variable per Module.
DenseMap<Module *, GlobalVariable *> ModuleToMergedGV;
bool HasChanged = false;
// Traverse all insertion points in all the function.
for (InsertionPointsPerFunc::iterator FctToInstPtsIt = InsPtsPerFunc.begin(),
EndIt = InsPtsPerFunc.end();
FctToInstPtsIt != EndIt; ++FctToInstPtsIt) {
InsertionPoints &InsertPts = FctToInstPtsIt->second;
// Do more checking for debug purposes.
#ifndef NDEBUG
DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>(
*FctToInstPtsIt->first).getDomTree();
#endif
GlobalVariable *PromotedGV;
assert(!InsertPts.empty() && "Empty uses does not need a definition");
Module *M = FctToInstPtsIt->first->getParent();
DenseMap<Module *, GlobalVariable *>::iterator MapIt =
ModuleToMergedGV.find(M);
if (MapIt == ModuleToMergedGV.end()) {
PromotedGV = new GlobalVariable(
*M, Cst->getType(), true, GlobalValue::InternalLinkage, nullptr,
"_PromotedConst", nullptr, GlobalVariable::NotThreadLocal);
PromotedGV->setInitializer(Cst);
ModuleToMergedGV[M] = PromotedGV;
DEBUG(dbgs() << "Global replacement: ");
DEBUG(PromotedGV->print(dbgs()));
DEBUG(dbgs() << '\n');
++NumPromoted;
HasChanged = true;
} else {
PromotedGV = MapIt->second;
}
for (InsertionPoints::iterator IPI = InsertPts.begin(),
EndIPI = InsertPts.end();
IPI != EndIPI; ++IPI) {
// Create the load of the global variable.
IRBuilder<> Builder(IPI->first->getParent(), IPI->first);
LoadInst *LoadedCst = Builder.CreateLoad(PromotedGV);
DEBUG(dbgs() << "**********\n");
DEBUG(dbgs() << "New def: ");
DEBUG(LoadedCst->print(dbgs()));
DEBUG(dbgs() << '\n');
// Update the dominated uses.
Users &DominatedUsers = IPI->second;
for (Value::user_iterator Use : DominatedUsers) {
#ifndef NDEBUG
assert((DT.dominates(LoadedCst, cast<Instruction>(*Use)) ||
(isa<PHINode>(*Use) &&
DT.dominates(LoadedCst, findInsertionPoint(Use)))) &&
"Inserted definition does not dominate all its uses!");
#endif
DEBUG(dbgs() << "Use to update " << Use.getOperandNo() << ":");
DEBUG(Use->print(dbgs()));
DEBUG(dbgs() << '\n');
Use->setOperand(Use.getOperandNo(), LoadedCst);
++NumPromotedUses;
}
}
}
return HasChanged;
}
