[PM] Use range-based for loops in LegacyPassManager.cpp (NFC).

[fhahn]

Summary

This patch replaces a bunch of iterator-based for loops with range-based
for loops. There are 2 iterator-based loops left in this file in
removeNotPreservedAnalysis, but I think those cannot be replaced by
range-based for loops as they modify the container they are iterating
over.

Unless I missed something, this schould be a NFC and I would appreciate
if someone could have a quick look to confirm that.

[mehdi_amini]

lib/IR/LegacyPassManager.cpp

641

Shouldn't this be a break;?

1255

Side note but: why don't we use unique_ptr? (always surprised when I see delete used)

[fhahn]

Use break instead of continue

lib/IR/LegacyPassManager.cpp

641

Ah yes!

1255

I can check how much effort using unique_ptr would be and will submit a separate patch if it's feasible.

[jhenderson]

LGTM, with one minor request.

lib/IR/LegacyPassManager.cpp

1073–1074

Could you use ID here instead of I, please, for consistency (and readability)?

[fhahn]

Changed I -> ID

[fhahn]

Thanks James & Mehdi

lib/IR/LegacyPassManager.cpp

void PMTopLevelManager::schedulePass(Pass *P) {
 
   AnalysisUsage *AnUsage = findAnalysisUsage(P);
 
   bool checkAnalysis = true;
   while (checkAnalysis) {
     checkAnalysis = false;
 
     const AnalysisUsage::VectorType &RequiredSet = AnUsage->getRequiredSet();
-    for (AnalysisUsage::VectorType::const_iterator I = RequiredSet.begin(),
-           E = RequiredSet.end(); I != E; ++I) {
+    for (const AnalysisID ID : RequiredSet) {
 
-      Pass *AnalysisPass = findAnalysisPass(*I);
+      Pass *AnalysisPass = findAnalysisPass(ID);
       if (!AnalysisPass) {
-        const PassInfo *PI = findAnalysisPassInfo(*I);
+        const PassInfo *PI = findAnalysisPassInfo(ID);
 
         if (!PI) {
           // Pass P is not in the global PassRegistry
           dbgs() << "Pass '"  << P->getPassName() << "' is not initialized." << "\n";
           dbgs() << "Verify if there is a pass dependency cycle." << "\n";
           dbgs() << "Required Passes:" << "\n";
-          for (AnalysisUsage::VectorType::const_iterator I2 = RequiredSet.begin(),
-                 E = RequiredSet.end(); I2 != E && I2 != I; ++I2) {
-            Pass *AnalysisPass2 = findAnalysisPass(*I2);
+          for (const AnalysisID ID2 : RequiredSet) {
+            if (ID == ID2)
+              break;
+            Pass *AnalysisPass2 = findAnalysisPass(ID2);
             if (AnalysisPass2) {
               dbgs() << "\t" << AnalysisPass2->getPassName() << "\n";
             } else {
               dbgs() << "\t"   << "Error: Required pass not found! Possible causes:"  << "\n";
               dbgs() << "\t\t" << "- Pass misconfiguration (e.g.: missing macros)"    << "\n";
               dbgs() << "\t\t" << "- Corruption of the global PassRegistry"           << "\n";
             }
           }

 // All Required analyses should be available to the pass as it runs!  Here
 // we fill in the AnalysisImpls member of the pass so that it can
 // successfully use the getAnalysis() method to retrieve the
 // implementations it needs.
 //
 void PMDataManager::initializeAnalysisImpl(Pass *P) {
   AnalysisUsage *AnUsage = TPM->findAnalysisUsage(P);
 
-  for (AnalysisUsage::VectorType::const_iterator
-         I = AnUsage->getRequiredSet().begin(),
-         E = AnUsage->getRequiredSet().end(); I != E; ++I) {
-    Pass *Impl = findAnalysisPass(*I, true);
+  for (const AnalysisID ID : AnUsage->getRequiredSet()) {
+    Pass *Impl = findAnalysisPass(ID, true);
     if (!Impl)
       // This may be analysis pass that is initialized on the fly.
       // If that is not the case then it will raise an assert when it is used.
       continue;
     AnalysisResolver *AR = P->getResolver();
     assert(AR && "Analysis Resolver is not set");
-    AR->addAnalysisImplsPair(*I, Impl);
+    AR->addAnalysisImplsPair(ID, Impl);
   }
 }
 
 /// Find the pass that implements Analysis AID. If desired pass is not found
 /// then return NULL.
 Pass *PMDataManager::findAnalysisPass(AnalysisID AID, bool SearchParent) {
 
   // Check if AvailableAnalysis map has one entry.
void PMDataManager::dumpLastUses(Pass *P, unsigned Offset) const{
   SmallVector<Pass *, 12> LUses;
 
   // If this is a on the fly manager then it does not have TPM.
   if (!TPM)
     return;
 
   TPM->collectLastUses(LUses, P);
 
-  for (SmallVectorImpl<Pass *>::iterator I = LUses.begin(),
-         E = LUses.end(); I != E; ++I) {
+  for (Pass *P : LUses) {
     dbgs() << "--" << std::string(Offset*2, ' ');
-    (*I)->dumpPassStructure(0);
+    P->dumpPassStructure(0);
   }
 }
 
 void PMDataManager::dumpPassArguments() const {
-  for (SmallVectorImpl<Pass *>::const_iterator I = PassVector.begin(),
-        E = PassVector.end(); I != E; ++I) {
-    if (PMDataManager *PMD = (*I)->getAsPMDataManager())
+  for (Pass *P : PassVector) {
+    if (PMDataManager *PMD = P->getAsPMDataManager())
       PMD->dumpPassArguments();
     else
       if (const PassInfo *PI =
-            TPM->findAnalysisPassInfo((*I)->getPassID()))
+            TPM->findAnalysisPassInfo(P->getPassID()))
         if (!PI->isAnalysisGroup())
           dbgs() << " -" << PI->getPassArgument();
   }
 }
 
 void PMDataManager::dumpPassInfo(Pass *P, enum PassDebuggingString S1,
                                  enum PassDebuggingString S2,
                                  StringRef Msg) {

 }
 
 Pass *PMDataManager::getOnTheFlyPass(Pass *P, AnalysisID PI, Function &F) {
   llvm_unreachable("Unable to find on the fly pass");
 }
 
 // Destructor
 PMDataManager::~PMDataManager() {
-  for (SmallVectorImpl<Pass *>::iterator I = PassVector.begin(),
-         E = PassVector.end(); I != E; ++I)
-    delete *I;
+  for (Pass *P : PassVector)
+    delete P;
 }
 
 //===----------------------------------------------------------------------===//
 // NOTE: Is this the right place to define this method ?
 // getAnalysisIfAvailable - Return analysis result or null if it doesn't exist.
 Pass *AnalysisResolver::getAnalysisIfAvailable(AnalysisID ID, bool dir) const {
   return PM.findAnalysisPass(ID, dir);
 }

 /// runOnBasicBlock method.  Keep track of whether any of the passes modifies
 /// the function, and if so, return true.
 bool BBPassManager::runOnFunction(Function &F) {
   if (F.isDeclaration())
     return false;
 
   bool Changed = doInitialization(F);
 
-  for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
+  for (BasicBlock &BB : F)
     for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
       BasicBlockPass *BP = getContainedPass(Index);
       bool LocalChanged = false;
 
-      dumpPassInfo(BP, EXECUTION_MSG, ON_BASICBLOCK_MSG, I->getName());
+      dumpPassInfo(BP, EXECUTION_MSG, ON_BASICBLOCK_MSG, BB.getName());
       dumpRequiredSet(BP);
 
       initializeAnalysisImpl(BP);
 
       {
         // If the pass crashes, remember this.
-        PassManagerPrettyStackEntry X(BP, *I);
+        PassManagerPrettyStackEntry X(BP, BB);
         TimeRegion PassTimer(getPassTimer(BP));
 
-        LocalChanged |= BP->runOnBasicBlock(*I);
+        LocalChanged |= BP->runOnBasicBlock(BB);
       }
 
       Changed |= LocalChanged;
       if (LocalChanged)
         dumpPassInfo(BP, MODIFICATION_MSG, ON_BASICBLOCK_MSG,
-                     I->getName());
+                     BB.getName());
       dumpPreservedSet(BP);
       dumpUsedSet(BP);
 
       verifyPreservedAnalysis(BP);
       removeNotPreservedAnalysis(BP);
       recordAvailableAnalysis(BP);
-      removeDeadPasses(BP, I->getName(), ON_BASICBLOCK_MSG);
+      removeDeadPasses(BP, BB.getName(), ON_BASICBLOCK_MSG);
     }
 
   return doFinalization(F) || Changed;
 }
 
 // Implement doInitialization and doFinalization
 bool BBPassManager::doInitialization(Module &M) {
   bool Changed = false;