Index: lib/Object/COFFObjectFile.cpp
===================================================================
--- lib/Object/COFFObjectFile.cpp
+++ lib/Object/COFFObjectFile.cpp
@@ -883,7 +883,7 @@
 }
 
 uint8_t COFFObjectFile::getBytesInAddress() const {
-  return getArch() == Triple::x86_64 ? 8 : 4;
+  return getArch() == Triple::x86_64 || getArch() == Triple::aarch64 ? 8 : 4;
 }
 
 StringRef COFFObjectFile::getFileFormatName() const {
Index: test/tools/llvm-readobj/file-headers.test
===================================================================
--- test/tools/llvm-readobj/file-headers.test
+++ test/tools/llvm-readobj/file-headers.test
@@ -1,5 +1,7 @@
 RUN: llvm-readobj -h %p/Inputs/trivial.obj.coff-arm \
 RUN:   | FileCheck %s -check-prefix COFF-ARM
+RUN: llvm-readobj -h %p/Inputs/trivial.obj.coff-arm64 \
+RUN:   | FileCheck %s -check-prefix COFF-ARM64
 RUN: llvm-readobj -h %p/Inputs/trivial.obj.coff-i386 \
 RUN:   | FileCheck %s -check-prefix COFF32
 RUN: llvm-readobj -h %p/Inputs/trivial.obj.coff-x86-64 \
@@ -47,6 +49,21 @@
 COFF-ARM-NEXT:   ]
 COFF-ARM-NEXT: }
 
+COFF-ARM64:      File: {{(.*[/\\])?}}trivial.obj.coff-arm64
+COFF-ARM64-NEXT: Format: COFF-ARM64
+COFF-ARM64-NEXT: Arch: aarch64
+COFF-ARM64-NEXT: AddressSize: 64bit
+COFF-ARM64-NEXT: ImageFileHeader {
+COFF-ARM64-NEXT:   Machine: IMAGE_FILE_MACHINE_ARM64 (0xAA64)
+COFF-ARM64-NEXT:   SectionCount: 1
+COFF-ARM64-NEXT:   TimeDateStamp: 1970-01-01 00:00:00 (0x0)
+COFF-ARM64-NEXT:   PointerToSymbolTable: 0x44
+COFF-ARM64-NEXT:   SymbolCount: 3
+COFF-ARM64-NEXT:   OptionalHeaderSize: 0
+COFF-ARM64-NEXT:   Characteristics [ (0x0)
+COFF-ARM64-NEXT:   ]
+COFF-ARM64-NEXT: }
+
 COFF32:      File: {{(.*[/\\])?}}trivial.obj.coff-i386
 COFF32-NEXT: Format: COFF-i386
 COFF32-NEXT: Arch: i386
Index: tools/llvm-readobj/COFFDumper.cpp
===================================================================
--- tools/llvm-readobj/COFFDumper.cpp
+++ tools/llvm-readobj/COFFDumper.cpp
@@ -335,6 +335,7 @@
   LLVM_READOBJ_ENUM_ENT(COFF, IMAGE_FILE_MACHINE_AM33     ),
   LLVM_READOBJ_ENUM_ENT(COFF, IMAGE_FILE_MACHINE_AMD64    ),
   LLVM_READOBJ_ENUM_ENT(COFF, IMAGE_FILE_MACHINE_ARM      ),
+  LLVM_READOBJ_ENUM_ENT(COFF, IMAGE_FILE_MACHINE_ARM64    ),
   LLVM_READOBJ_ENUM_ENT(COFF, IMAGE_FILE_MACHINE_ARMNT    ),
   LLVM_READOBJ_ENUM_ENT(COFF, IMAGE_FILE_MACHINE_EBC      ),
   LLVM_READOBJ_ENUM_ENT(COFF, IMAGE_FILE_MACHINE_I386     ),