Add support for building for Windows ARM64 devices

README.md

@@ -174,9 +174,13 @@ Or for visionOS:
 
 ##### Windows:
 
-Launch the "x64 Native Tools Command Prompt" for your version of Visual Studio
-and run the script in the opened shell. Make sure to use the 64-bit (x64) 
-command prompt and not the 32-bit (x86) command prompt.
+On Windows, it is possible to compile for either x64, or ARM64.
+**Note**: ARM64EC is not compatible at this time.
+
+Launch the "x64 Native Tools Command Prompt" (or "ARM64 Native Tools Command
+Prompt" where appropriate) for your version of Visual Studio, and run the script
+in the opened shell. Make sure to use the appropriate version of the command
+prompt (e.g. on x64, use the x64 version, not the x86 version).
 
 See https://docs.microsoft.com/en-us/cpp/build/how-to-enable-a-64-bit-visual-cpp-toolset-on-the-command-line for more details.
 

build_scripts/build_usd.py

@@ -152,6 +152,18 @@ def IsVisualStudio2017OrGreater():
     VISUAL_STUDIO_2017_VERSION = (14, 1)
     return IsVisualStudioVersionOrGreater(VISUAL_STUDIO_2017_VERSION)
 
+# Helper to get the current host arch on Windows
+def GetWindowsHostArch():
+    identifier = os.environ.get('PROCESSOR_IDENTIFIER')
+    # ARM64 identifiers currently start with "ARMv8 ...."
+    # Note: This could be modified in the future to distinguish between ARMv8 and ARMv9
+    if "ARM" in identifier:
+        return "ARM64"
+    elif any(x64Arch in identifier for x64Arch in ["AMD64", "Intel64", "EM64T"]):
+        return "x64"
+    else:
+        raise RuntimeError("Unknown Windows host arch")
+
 def GetPythonInfo(context):
     """Returns a tuple containing the path to the Python executable, shared
     library, and include directory corresponding to the version of Python
@@ -393,7 +405,8 @@ def RunCMake(context, force, extraArgs = None):
 
     # Note - don't want to add -A (architecture flag) if generator is, ie, Ninja
     if IsVisualStudio2019OrGreater() and "Visual Studio" in generator:
-        generator = generator + " -A x64"
+        windowsHostArch = GetWindowsHostArch()
+        generator = generator + " -A " + windowsHostArch
 
     toolset = context.cmakeToolset
     if toolset is not None:

pxr/base/arch/defines.h

@@ -35,15 +35,17 @@
 #if defined(i386) || defined(__i386__) || defined(__x86_64__) || \
     defined(_M_IX86) || defined(_M_X64)
 #define ARCH_CPU_INTEL
-#elif defined(__arm__) || defined(__aarch64__) || defined(_M_ARM)
+#elif defined(__arm__) || defined(__aarch64__) || defined(_M_ARM) || \
+    defined(_M_ARM64)
 #define ARCH_CPU_ARM
 #endif
 
 //
 // Bits
 //
 
-#if defined(__x86_64__) || defined(__aarch64__) || defined(_M_X64)
+#if defined(__x86_64__) || defined(__aarch64__) || defined(_M_X64) || \
+    defined(_M_ARM64)
 #define ARCH_BITS_64
 #else
 #error "Unsupported architecture.  x86_64 or ARM64 required."

pxr/base/arch/timing.h

@@ -52,7 +52,13 @@ ArchGetTickTime()
     return __rdtsc();
 #elif defined (ARCH_CPU_ARM)
     uint64_t result;
+    #if defined(ARCH_COMPILER_MSVC)
+    // MSVC does not support inline assembly on ARM64 platforms
+    // 0x5F02 == ARM64_CNTVCT - manually calculated value avoids <windows.h>
+    result = _ReadStatusReg(0x5F02);
+    #else
     __asm __volatile("mrs	%0, CNTVCT_EL0" : "=&r" (result));
+    #endif
     return result;
 #else
 #error Unknown architecture.
@@ -68,7 +74,8 @@ inline uint64_t
 ArchGetStartTickTime()
 {
     uint64_t t;
-#if defined (ARCH_OS_DARWIN)
+#if defined (ARCH_OS_DARWIN) || \
+    (defined (ARCH_CPU_ARM) && defined (ARCH_COMPILER_MSVC))
     return ArchGetTickTime();
 #elif defined (ARCH_CPU_ARM)
     std::atomic_signal_fence(std::memory_order_seq_cst);
@@ -109,7 +116,8 @@ inline uint64_t
 ArchGetStopTickTime()
 {
     uint64_t t;
-#if defined (ARCH_OS_DARWIN)
+#if defined (ARCH_OS_DARWIN) || \
+    (defined (ARCH_CPU_ARM) && defined (ARCH_COMPILER_MSVC))
     return ArchGetTickTime();
 #elif defined (ARCH_CPU_ARM)
     std::atomic_signal_fence(std::memory_order_seq_cst);