Index: lld/trunk/COFF/Config.h
===================================================================
--- lld/trunk/COFF/Config.h
+++ lld/trunk/COFF/Config.h
@@ -31,6 +31,7 @@
 
 // Short aliases.
 static const auto AMD64 = llvm::COFF::IMAGE_FILE_MACHINE_AMD64;
+static const auto ARM64 = llvm::COFF::IMAGE_FILE_MACHINE_ARM64;
 static const auto ARMNT = llvm::COFF::IMAGE_FILE_MACHINE_ARMNT;
 static const auto I386 = llvm::COFF::IMAGE_FILE_MACHINE_I386;
 
@@ -73,7 +74,7 @@
 // Global configuration.
 struct Configuration {
   enum ManifestKind { SideBySide, Embed, No };
-  bool is64() { return Machine == AMD64; }
+  bool is64() { return Machine == AMD64 || Machine == ARM64; }
 
   llvm::COFF::MachineTypes Machine = IMAGE_FILE_MACHINE_UNKNOWN;
   bool Verbose = false;
Index: lld/trunk/COFF/DriverUtils.cpp
===================================================================
--- lld/trunk/COFF/DriverUtils.cpp
+++ lld/trunk/COFF/DriverUtils.cpp
@@ -85,6 +85,7 @@
                         .Cases("x64", "amd64", AMD64)
                         .Cases("x86", "i386", I386)
                         .Case("arm", ARMNT)
+                        .Case("arm64", ARM64)
                         .Default(IMAGE_FILE_MACHINE_UNKNOWN);
   if (MT != IMAGE_FILE_MACHINE_UNKNOWN)
     return MT;
@@ -95,6 +96,8 @@
   switch (MT) {
   case ARMNT:
     return "arm";
+  case ARM64:
+    return "arm64";
   case AMD64:
     return "x64";
   case I386:
Index: lld/trunk/COFF/InputFiles.cpp
===================================================================
--- lld/trunk/COFF/InputFiles.cpp
+++ lld/trunk/COFF/InputFiles.cpp
@@ -380,6 +380,8 @@
     return I386;
   case Triple::arm:
     return ARMNT;
+  case Triple::aarch64:
+    return ARM64;
   default:
     return IMAGE_FILE_MACHINE_UNKNOWN;
   }
Index: lld/trunk/test/COFF/arm64-magic.yaml
===================================================================
--- lld/trunk/test/COFF/arm64-magic.yaml
+++ lld/trunk/test/COFF/arm64-magic.yaml
@@ -0,0 +1,46 @@
+# RUN: yaml2obj < %s > %t.obj
+# RUN: lld-link /out:%t.exe /entry:mainCRTStartup /subsystem:console %t.obj
+# RUN: llvm-readobj -file-headers %t.exe | FileCheck %s
+
+# CHECK: Format: COFF-ARM64
+# CHECK: Arch: aarch64
+# CHECK: AddressSize: 64bit
+# CHECK: ImageFileHeader {
+# CHECK:   Machine: IMAGE_FILE_MACHINE_ARM64 (0xAA64)
+# CHECK:   Characteristics [ (0x22)
+# CHECK:     IMAGE_FILE_EXECUTABLE_IMAGE (0x2)
+# CHECK:     IMAGE_FILE_LARGE_ADDRESS_AWARE (0x20)
+# CHECK:   ]
+# CHECK: }
+# CHECK: ImageOptionalHeader {
+# CHECK:   Magic: 0x20B
+
+--- !COFF
+header:
+  Machine:         IMAGE_FILE_MACHINE_ARM64
+  Characteristics: []
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_PURGEABLE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    Alignment:       4
+    SectionData:     'e0031f2ac0035fd6'
+symbols:
+  - Name:            .text
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+    SectionDefinition:
+      Length:          8
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          1
+  - Name:            mainCRTStartup
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+...