Index: llvm/trunk/test/tools/yaml2obj/coff-arm64.yaml
===================================================================
--- llvm/trunk/test/tools/yaml2obj/coff-arm64.yaml
+++ llvm/trunk/test/tools/yaml2obj/coff-arm64.yaml
@@ -0,0 +1,89 @@
+# RUN: yaml2obj %s -o %t
+# RUN: llvm-readobj -file-headers %t | FileCheck %s
+
+# CHECK: OptionalHeaderSize: 240
+
+--- !COFF
+OptionalHeader:  
+  AddressOfEntryPoint: 4096
+  ImageBase:       1073741824
+  SectionAlignment: 4096
+  FileAlignment:   512
+  MajorOperatingSystemVersion: 6
+  MinorOperatingSystemVersion: 0
+  MajorImageVersion: 0
+  MinorImageVersion: 0
+  MajorSubsystemVersion: 6
+  MinorSubsystemVersion: 0
+  Subsystem:       IMAGE_SUBSYSTEM_WINDOWS_CUI
+  DLLCharacteristics: [ IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA, IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE, IMAGE_DLL_CHARACTERISTICS_NX_COMPAT, IMAGE_DLL_CHARACTERISTICS_TERMINAL_SERVER_AWARE ]
+  SizeOfStackReserve: 1048576
+  SizeOfStackCommit: 4096
+  SizeOfHeapReserve: 1048576
+  SizeOfHeapCommit: 4096
+  ExportTable:     
+    RelativeVirtualAddress: 0
+    Size:            0
+  ImportTable:     
+    RelativeVirtualAddress: 0
+    Size:            0
+  ResourceTable:   
+    RelativeVirtualAddress: 0
+    Size:            0
+  ExceptionTable:  
+    RelativeVirtualAddress: 12288
+    Size:            8
+  CertificateTable: 
+    RelativeVirtualAddress: 0
+    Size:            0
+  BaseRelocationTable: 
+    RelativeVirtualAddress: 0
+    Size:            0
+  Debug:           
+    RelativeVirtualAddress: 0
+    Size:            0
+  Architecture:    
+    RelativeVirtualAddress: 0
+    Size:            0
+  GlobalPtr:       
+    RelativeVirtualAddress: 0
+    Size:            0
+  TlsTable:        
+    RelativeVirtualAddress: 0
+    Size:            0
+  LoadConfigTable: 
+    RelativeVirtualAddress: 0
+    Size:            0
+  BoundImport:     
+    RelativeVirtualAddress: 0
+    Size:            0
+  IAT:             
+    RelativeVirtualAddress: 0
+    Size:            0
+  DelayImportDescriptor: 
+    RelativeVirtualAddress: 0
+    Size:            0
+  ClrRuntimeHeader: 
+    RelativeVirtualAddress: 0
+    Size:            0
+header:          
+  Machine:         IMAGE_FILE_MACHINE_ARM64
+  Characteristics: [ IMAGE_FILE_EXECUTABLE_IMAGE, IMAGE_FILE_LARGE_ADDRESS_AWARE ]
+sections:        
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    VirtualAddress:  1073745920
+    VirtualSize:     4
+    SectionData:     C0035FD6
+  - Name:            .rdata
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]
+    VirtualAddress:  1073750016
+    VirtualSize:     12
+    SectionData:     0100400800000000E4E3E3E3
+  - Name:            .pdata
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]
+    VirtualAddress:  1073754112
+    VirtualSize:     8
+    SectionData:     '0010000000200000'
+symbols:         []
+...
Index: llvm/trunk/tools/yaml2obj/yaml2coff.cpp
===================================================================
--- llvm/trunk/tools/yaml2obj/yaml2coff.cpp
+++ llvm/trunk/tools/yaml2obj/yaml2coff.cpp
@@ -46,7 +46,8 @@
 
   bool isPE() const { return Obj.OptionalHeader.hasValue(); }
   bool is64Bit() const {
-    return Obj.Header.Machine == COFF::IMAGE_FILE_MACHINE_AMD64;
+    return Obj.Header.Machine == COFF::IMAGE_FILE_MACHINE_AMD64 ||
+           Obj.Header.Machine == COFF::IMAGE_FILE_MACHINE_ARM64;
   }
 
   uint32_t getFileAlignment() const {