[NFC] Finish clang-tidy cleanup

- Follow up on previous clang-tidy changes. Finish up clang-tidy changes
  of remaining project sources.
- Add support to enable clang-tidy checks on project source files
  by adding a new cmake variable viz., MCTOLL_CLANG_TIDY, that can be
  specified while configuring cmake.
- Update README.md

.clang-format

@@ -68,7 +68,7 @@ ForEachMacros:
   - BOOST_FOREACH
 IncludeBlocks:   Preserve
 IncludeCategories:
-  - Regex:           '^"(llvm|llvm-c|clang|clang-c)/'
+  - Regex:           '^"(llvm-|llvm|clang-c|clang)/'
     Priority:        2
     SortPriority:    0
   - Regex:           '^(<|"(gtest|gmock|isl|json)/)'
@@ -105,7 +105,7 @@ PenaltyExcessCharacter: 1000000
 PenaltyReturnTypeOnItsOwnLine: 60
 PointerAlignment: Right
 ReflowComments:  true
-SortIncludes:    CaseInsensitive
+SortIncludes:    CaseSensitive
 SortUsingDeclarations: true
 SpaceAfterCStyleCast: false
 SpaceAfterLogicalNot: false

ARM/ARMArgumentRaiser.cpp

@@ -163,7 +163,7 @@ bool ARMArgumentRaiser::raiseArgs() {
        ArgIter != ArgEnd; ++ArgIter)
     ArgIter->setName("arg." + std::to_string(ArgIdx++));
 
-  for (unsigned i = 0, End = RF->arg_size() + 1; i < End; ++i) {
+  for (unsigned Idx = 0, End = RF->arg_size() + 1; Idx < End; ++Idx) {
     Align ALG(32);
     MFI->CreateStackObject(32, ALG, false);
   }

ARM/ARMCreateJumpTable.cpp

@@ -85,8 +85,8 @@ MachineBasicBlock *ARMCreateJumpTable::checkJumptableBB(MachineFunction &MF) {
       }
     }
 
-    for (unsigned int i = 0; i < Instrs.size(); i++) {
-      MBB->erase(Instrs[i]);
+    for (unsigned int Idx = 0; Idx < Instrs.size(); Idx++) {
+      MBB->erase(Instrs[Idx]);
     }
   }
   return JumpTableBB;
@@ -103,16 +103,16 @@ bool ARMCreateJumpTable::updatetheBranchInst(MachineBasicBlock &MBB) {
     MachineInstr &CurMI = (*MIIter);
 
     if (CurMI.getOpcode() == ARM::Bcc) {
-      for (unsigned int i = 0; i < CurMI.getNumOperands(); i++) {
-        LLVM_DEBUG(CurMI.getOperand(i).dump());
+      for (unsigned int Idx = 0; Idx < CurMI.getNumOperands(); Idx++) {
+        LLVM_DEBUG(CurMI.getOperand(Idx).dump());
       }
       BuildMI(&MBB, DebugLoc(), TII->get(ARM::B)).add(CurMI.getOperand(0));
       Instrs.push_back(&CurMI);
     }
   }
 
-  for (unsigned int i = 0; i < Instrs.size(); i++) {
-    MBB.erase(Instrs[i]);
+  for (unsigned int Idx = 0; Idx < Instrs.size(); Idx++) {
+    MBB.erase(Instrs[Idx]);
   }
   return true;
 }
@@ -122,8 +122,8 @@ bool ARMCreateJumpTable::raiseMaichineJumpTable(MachineFunction &MF) {
   // A vector to record MBBs that need to be erased upon jump table creation.
   std::vector<MachineBasicBlock *> MBBsToBeErased;
 
-  std::map<uint64_t, MCInstOrData> mcInstMapData;
-  MCInstRaiser::const_mcinst_iter iter_in;
+  std::map<uint64_t, MCInstOrData> MCInstMapData;
+  MCInstRaiser::const_mcinst_iter IterIn;
 
   // Save the ADDri and Calculate the start address of data.
   for (MachineBasicBlock &JmpTblBaseCalcMBB : MF) {
@@ -156,20 +156,20 @@ bool ARMCreateJumpTable::raiseMaichineJumpTable(MachineFunction &MF) {
         assert(
             MCIR != nullptr &&
             "Current function machine instruction raiser wasn't initialized!");
-        for (iter_in = MCIR->const_mcinstr_begin();
-             iter_in != MCIR->const_mcinstr_end(); iter_in++) {
-          MCInstOrData mcInstorData = iter_in->second;
-          if (mcInstorData.isData() && mcInstorData.getData() > 0) {
+        for (IterIn = MCIR->const_mcinstr_begin();
+             IterIn != MCIR->const_mcinstr_end(); IterIn++) {
+          MCInstOrData MCInstorData = IterIn->second;
+          if (MCInstorData.isData() && MCInstorData.getData() > 0) {
             // The 16 is 8 + 8. The first 8 is the PC offset, the second 8 is
             // the immediate of current instruction.
             // If the current library is position-independent, the offset should
             // be CASE VALUE + PC + 8.
             // If the current library is not position-independent, the offset
             // should be CASE VALUE - text section address.
             uint64_t Offset =
-                IsFPIC ? (mcInstorData.getData() +
+                IsFPIC ? (MCInstorData.getData() +
                           MCIR->getMCInstIndex(JmpTblOffsetCalcMI) + 16)
-                       : (mcInstorData.getData() - MR->getTextSectionAddress());
+                       : (MCInstorData.getData() - MR->getTextSectionAddress());
             auto MBBNo = MCIR->getMBBNumberOfMCInstOffset(Offset, MF);
             if (MBBNo != -1) {
               MachineBasicBlock *MBB = MF.getBlockNumbered(MBBNo);

ARM/ARMEliminatePrologEpilog.cpp

@@ -41,8 +41,8 @@ bool ARMEliminatePrologEpilog::checkRegister(
   for (; Iter < Instrs.end(); ++Iter) {
     MachineInstr *MI = *Iter;
     if (MI->mayStore()) {
-      for (unsigned i = 0; i < MI->getNumOperands(); i++) {
-        MachineOperand MO = MI->getOperand(i);
+      for (unsigned Idx = 0; Idx < MI->getNumOperands(); Idx++) {
+        MachineOperand MO = MI->getOperand(Idx);
 
         // Compare the register number.
         if (MO.isReg() && MO.getReg() == Reg)
@@ -136,8 +136,8 @@ bool ARMEliminatePrologEpilog::eliminateProlog(MachineFunction &MF) const {
   const MCPhysReg *CSRegs = TRI->getCalleeSavedRegs(&MF);
 
   std::vector<CalleeSavedInfo> CSI;
-  for (unsigned i = 0; CSRegs[i]; ++i) {
-    unsigned Reg = CSRegs[i];
+  for (unsigned Idx = 0; CSRegs[Idx]; ++Idx) {
+    unsigned Reg = CSRegs[Idx];
 
     // Save register.
     if (checkRegister(Reg, PrologInstrs)) {
@@ -201,8 +201,8 @@ bool ARMEliminatePrologEpilog::eliminateProlog(MachineFunction &MF) const {
 
   // Eliminate the instructions identified in function prologue
   unsigned int DelInstSz = PrologInstrs.size();
-  for (unsigned int i = 0; i < DelInstSz; i++) {
-    FrontMBB.erase(PrologInstrs[i]);
+  for (unsigned int Idx = 0; Idx < DelInstSz; Idx++) {
+    FrontMBB.erase(PrologInstrs[Idx]);
   }
 
   return true;
@@ -281,8 +281,8 @@ bool ARMEliminatePrologEpilog::eliminateEpilog(MachineFunction &MF) const {
 
     // Eliminate the instructions identified in function epilogue
     unsigned int DelInstSz = EpilogInstrs.size();
-    for (unsigned int i = 0; i < DelInstSz; i++) {
-      MBB.erase(EpilogInstrs[i]);
+    for (unsigned int Idx = 0; Idx < DelInstSz; Idx++) {
+      MBB.erase(EpilogInstrs[Idx]);
     }
   }