[clang][syntax] Replace `std::vector<bool>` use

[jansvoboda11]

Summary

LLVM Programmer’s Manual strongly discourages the use of std::vector<bool> and suggests llvm::BitVector as a possible replacement.

This patch replaces std::vector<bool> with llvm::BitVector in the Format library and replaces range-based for loop with regular for loop. This is necessary due to llvm::BitVector not having begin() and end() (D117116).

[dblaikie]

Looks good, thanks!

[dexonsmith]

LGTM too.

clang/lib/Tooling/Syntax/Tree.cpp

 //===- Tree.cpp -----------------------------------------------*- C++ -*-=====//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 #include "clang/Tooling/Syntax/Tree.h"
 #include "clang/Basic/TokenKinds.h"
 #include "clang/Tooling/Syntax/Nodes.h"
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Casting.h"
 #include <cassert>
 
 using namespace clang;
 
 namespace {
 static void traverse(const syntax::Node *N,
static void dumpLeaf(raw_ostream &OS, const syntax::Leaf *L,
   // Handle 'eof' separately, calling text() on it produces an empty string.
   if (Token->kind() == tok::eof)
     OS << "<eof>";
   else
     OS << Token->text(SM);
 }
 
 static void dumpNode(raw_ostream &OS, const syntax::Node *N,
-                     const SourceManager &SM, std::vector<bool> IndentMask) {
+                     const SourceManager &SM, llvm::BitVector IndentMask) {
   auto DumpExtraInfo = [&OS](const syntax::Node *N) {
     if (N->getRole() != syntax::NodeRole::Unknown)
       OS << " " << N->getRole();
     if (!N->isOriginal())
       OS << " synthesized";
     if (!N->canModify())
       OS << " unmodifiable";
   };
static void dumpNode(raw_ostream &OS, const syntax::Node *N,
   }
 
   const auto *T = cast<syntax::Tree>(N);
   OS << T->getKind();
   DumpExtraInfo(N);
   OS << "\n";
 
   for (const syntax::Node &It : T->getChildren()) {
-    for (bool Filled : IndentMask) {
-      if (Filled)
+    for (unsigned Idx = 0; Idx < IndentMask.size(); ++Idx) {
+      if (IndentMask[Idx])
         OS << "| ";
       else
         OS << "  ";
     }
     if (!It.getNextSibling()) {
       OS << "`-";
       IndentMask.push_back(false);
     } else {