[BOLT] Use range-based for loops (NFC)

LLVM Coding Standards discourage for_each unless callable objects
already exist.

bolt/lib/Core/BinaryFunction.cpp

@@ -4419,12 +4419,14 @@ void BinaryFunction::printLoopInfo(raw_ostream &OS) const {
   OS << "\n";
 
   std::stack<BinaryLoop *> St;
-  for_each(*BLI, [&](BinaryLoop *L) { St.push(L); });
+  for (BinaryLoop *L : *BLI)
+    St.push(L);
   while (!St.empty()) {
     BinaryLoop *L = St.top();
     St.pop();
 
-    for_each(*L, [&](BinaryLoop *Inner) { St.push(Inner); });
+    for (BinaryLoop *Inner : *L)
+      St.push(Inner);
 
     if (!hasValidProfile())
       continue;

bolt/lib/Core/DebugData.cpp

@@ -1183,11 +1183,9 @@ void DebugAbbrevWriter::addUnitAbbreviations(DWARFUnit &Unit) {
       // FIXME: if we had a full access to DWARFDebugAbbrev::AbbrDeclSets
       // we wouldn't have to build our own sorted list for the quick lookup.
       if (AbbrevSetOffsets.empty()) {
-        for_each(
-            *Unit.getContext().getDebugAbbrev(),
-            [&](const std::pair<uint64_t, DWARFAbbreviationDeclarationSet> &P) {
-              AbbrevSetOffsets.push_back(P.first);
-            });
+        for (const std::pair<const uint64_t, DWARFAbbreviationDeclarationSet>
+                 &P : *Unit.getContext().getDebugAbbrev())
+          AbbrevSetOffsets.push_back(P.first);
         sort(AbbrevSetOffsets);
       }
       auto It = upper_bound(AbbrevSetOffsets, StartOffset);

bolt/lib/Core/FunctionLayout.cpp

@@ -151,8 +151,9 @@ void FunctionLayout::eraseBasicBlocks(
   };
   const FragmentListType::iterator EmptyTailBegin =
       llvm::find_if_not(reverse(Fragments), IsEmpty).base();
-  std::for_each(EmptyTailBegin, Fragments.end(),
-                [](FunctionFragment *const FF) { delete FF; });
+  for (FunctionFragment *const FF :
+       llvm::make_range(EmptyTailBegin, Fragments.end()))
+    delete FF;
   Fragments.erase(EmptyTailBegin, Fragments.end());
 
   updateLayoutIndices();
@@ -208,8 +209,8 @@ void FunctionLayout::clear() {
   // be written to the output stream at its original file offset (see
   // `RewriteInstance::rewriteFile`). Hence, when the layout is cleared, retain
   // the main fragment, so that this information is not lost.
-  std::for_each(Fragments.begin() + 1, Fragments.end(),
-                [](FunctionFragment *const FF) { delete FF; });
+  for (FunctionFragment *const FF : llvm::drop_begin(Fragments))
+    delete FF;
   Fragments = FragmentListType{Fragments.front()};
   getMainFragment().Size = 0;
 }

bolt/lib/Passes/SplitFunctions.cpp

@@ -129,11 +129,11 @@ struct SplitProfile2 {
   }
 
   template <typename It> void partition(const It Start, const It End) const {
-    std::for_each(Start, End, [](BinaryBasicBlock *const BB) {
+    for (BinaryBasicBlock *const BB : llvm::make_range(Start, End)) {
       assert(BB->canOutline() &&
              "Moving a block that is not outlineable to cold fragment");
       BB->setFragmentNum(FragmentNum::cold());
-    });
+    }
   }
 };
 
@@ -155,9 +155,8 @@ struct SplitRandom2 {
     std::uniform_int_distribution<DiffT> Dist(MinimumSplit,
                                               NumOutlineableBlocks);
     const DiffT NumColdBlocks = Dist(*Gen);
-    std::for_each(End - NumColdBlocks, End, [](BinaryBasicBlock *BB) {
+    for (BinaryBasicBlock *BB : llvm::make_range(End - NumColdBlocks, End))
       BB->setFragmentNum(FragmentNum::cold());
-    });
 
     LLVM_DEBUG(dbgs() << formatv("BOLT-DEBUG: randomly chose last {0} (out of "
                                  "{1} possible) blocks to split\n",
@@ -216,11 +215,11 @@ struct SplitAll {
 
   template <typename It> void partition(It Start, It End) const {
     unsigned Fragment = 1;
-    std::for_each(Start, End, [&](BinaryBasicBlock *const BB) {
+    for (BinaryBasicBlock *const BB : llvm::make_range(Start, End)) {
       assert(BB->canOutline() &&
              "Moving a block that is not outlineable to cold fragment");
       BB->setFragmentNum(FragmentNum(Fragment++));
-    });
+    }
   }
 };
 } // namespace