diff --git a/lld/COFF/Chunks.cpp b/lld/COFF/Chunks.cpp
--- a/lld/COFF/Chunks.cpp
+++ b/lld/COFF/Chunks.cpp
@@ -12,14 +12,15 @@
 #include "SymbolTable.h"
 #include "Symbols.h"
 #include "Writer.h"
-#include "llvm/ADT/Twine.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/Twine.h"
 #include "llvm/BinaryFormat/COFF.h"
 #include "llvm/Object/COFF.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
+#include <iterator>
 
 using namespace llvm;
 using namespace llvm::object;
@@ -947,7 +948,7 @@
 void MergeChunk::addSection(COFFLinkerContext &ctx, SectionChunk *c) {
   assert(isPowerOf2_32(c->getAlignment()));
   uint8_t p2Align = llvm::Log2_32(c->getAlignment());
-  assert(p2Align < array_lengthof(ctx.mergeChunkInstances));
+  assert(p2Align < std::size(ctx.mergeChunkInstances));
   auto *&mc = ctx.mergeChunkInstances[p2Align];
   if (!mc)
     mc = make<MergeChunk>(c->getAlignment());