From 8263be5acc501f310292dc1167893b72927e666a Mon Sep 17 00:00:00 2001
From: Mugunthan Selvanayagam <mugunthan.selvanayagam@multicorewareinc.com>
Date: Tue, 31 Mar 2026 10:17:26 +0530
Subject: [PATCH] Add support for building and testing Folly on Windows ARM64

---
 .github/workflows/getdeps_windows_arm64.yml | 408 ++++++++++++++++++++
 build/fbcode_builder/getdeps/builder.py     |  32 +-
 build/fbcode_builder/getdeps/buildopts.py   |   4 +-
 build/fbcode_builder/getdeps/platform.py    |   2 +-
 folly/Portability.h                         |   8 +-
 folly/algorithm/simd/Movemask.h             |  28 +-
 folly/algorithm/simd/find_first_of.h        |  10 +-
 folly/chrono/Hardware.h                     |   2 +-
 folly/compression/Instructions.h            |  24 +-
 folly/container/detail/F14Table.h           |   8 +-
 folly/fibers/BoostContextCompatibility.h    | 115 +++++-
 folly/lang/Bits.h                           |  17 +-
 folly/portability/Asm.h                     |   2 +
 13 files changed, 626 insertions(+), 34 deletions(-)
 create mode 100644 .github/workflows/getdeps_windows_arm64.yml

diff --git a/.github/workflows/getdeps_windows_arm64.yml b/.github/workflows/getdeps_windows_arm64.yml
new file mode 100644
index 00000000000..a6d22d050de
--- /dev/null
+++ b/.github/workflows/getdeps_windows_arm64.yml
@@ -0,0 +1,408 @@
+# This file was @generated by getdeps.py
+
+name: Windows ARM64
+
+on:
+  push:
+    branches:
+    - main
+  pull_request:
+    branches:
+    - main
+
+permissions:
+  contents: read  #  to fetch code (actions/checkout)
+
+jobs:
+  build:
+    runs-on: windows-11-arm
+    steps:
+    - name: Set up Python
+      uses: actions/setup-python@v5
+      with:
+        python-version: '3.11'
+    - name: Export boost environment
+      run: "echo BOOST_ROOT=%BOOST_ROOT_1_83_0% >> %GITHUB_ENV%"
+      shell: cmd
+    - name: Fix Git config
+      run: >
+        git config --system core.longpaths true &&
+        git config --system core.autocrlf false &&
+        git config --system core.symlinks true
+      shell: cmd
+    - uses: actions/checkout@v6
+    - id: paths
+      name: Query paths
+      run: python build/fbcode_builder/getdeps.py query-paths --recursive --src-dir=. folly  >> $env:GITHUB_OUTPUT
+      shell: pwsh
+    - name: Fetch boost
+      if: ${{ steps.paths.outputs.boost_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests boost
+    - name: Fetch libsodium
+      if: ${{ steps.paths.outputs.libsodium_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests libsodium
+    - name: Fetch ninja
+      if: ${{ steps.paths.outputs.ninja_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests ninja
+    - name: Fetch cmake
+      if: ${{ steps.paths.outputs.cmake_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests cmake
+    - name: Fetch double-conversion
+      if: ${{ steps.paths.outputs.double-conversion_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests double-conversion
+    - name: Fetch fast_float
+      if: ${{ steps.paths.outputs.fast_float_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests fast_float
+    - name: Fetch fmt
+      if: ${{ steps.paths.outputs.fmt_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests fmt
+    - name: Fetch gflags
+      if: ${{ steps.paths.outputs.gflags_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests gflags
+    - name: Fetch glog
+      if: ${{ steps.paths.outputs.glog_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests glog
+    - name: Fetch googletest
+      if: ${{ steps.paths.outputs.googletest_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests googletest
+    - name: Fetch libdwarf
+      if: ${{ steps.paths.outputs.libdwarf_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests libdwarf
+    - name: Fetch lz4
+      if: ${{ steps.paths.outputs.lz4_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests lz4
+    - name: Fetch jom
+      if: ${{ steps.paths.outputs.jom_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests jom
+    - name: Fetch perl
+      if: ${{ steps.paths.outputs.perl_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests perl
+    - name: Fetch openssl
+      if: ${{ steps.paths.outputs.openssl_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests openssl
+    - name: Fetch snappy
+      if: ${{ steps.paths.outputs.snappy_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests snappy
+    - name: Fetch zlib
+      if: ${{ steps.paths.outputs.zlib_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests zlib
+    - name: Fetch zstd
+      if: ${{ steps.paths.outputs.zstd_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests zstd
+    - name: Fetch libevent
+      if: ${{ steps.paths.outputs.libevent_SOURCE }}
+      run: python build/fbcode_builder/getdeps.py fetch --no-tests libevent
+    - name: Restore boost from cache
+      id: restore_boost
+      if: ${{ steps.paths.outputs.boost_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.boost_INSTALL }}
+       key: ${{ steps.paths.outputs.boost_CACHE_KEY }}-install
+    - name: Build boost
+      if: ${{ steps.paths.outputs.boost_SOURCE && ! steps.restore_boost.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests boost
+    - name: Save boost to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.boost_SOURCE && ! steps.restore_boost.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.boost_INSTALL }}
+       key: ${{ steps.paths.outputs.boost_CACHE_KEY }}-install
+    - name: Restore libsodium from cache
+      id: restore_libsodium
+      if: ${{ steps.paths.outputs.libsodium_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.libsodium_INSTALL }}
+       key: ${{ steps.paths.outputs.libsodium_CACHE_KEY }}-install
+    - name: Build libsodium
+      if: ${{ steps.paths.outputs.libsodium_SOURCE && ! steps.restore_libsodium.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests libsodium
+    - name: Save libsodium to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.libsodium_SOURCE && ! steps.restore_libsodium.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.libsodium_INSTALL }}
+       key: ${{ steps.paths.outputs.libsodium_CACHE_KEY }}-install
+    - name: Restore ninja from cache
+      id: restore_ninja
+      if: ${{ steps.paths.outputs.ninja_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.ninja_INSTALL }}
+       key: ${{ steps.paths.outputs.ninja_CACHE_KEY }}-install
+    - name: Build ninja
+      if: ${{ steps.paths.outputs.ninja_SOURCE && ! steps.restore_ninja.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests ninja
+    - name: Save ninja to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.ninja_SOURCE && ! steps.restore_ninja.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.ninja_INSTALL }}
+       key: ${{ steps.paths.outputs.ninja_CACHE_KEY }}-install
+    - name: Restore cmake from cache
+      id: restore_cmake
+      if: ${{ steps.paths.outputs.cmake_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.cmake_INSTALL }}
+       key: ${{ steps.paths.outputs.cmake_CACHE_KEY }}-install
+    - name: Build cmake
+      if: ${{ steps.paths.outputs.cmake_SOURCE && ! steps.restore_cmake.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests cmake
+    - name: Save cmake to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.cmake_SOURCE && ! steps.restore_cmake.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.cmake_INSTALL }}
+       key: ${{ steps.paths.outputs.cmake_CACHE_KEY }}-install
+    - name: Restore double-conversion from cache
+      id: restore_double-conversion
+      if: ${{ steps.paths.outputs.double-conversion_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.double-conversion_INSTALL }}
+       key: ${{ steps.paths.outputs.double-conversion_CACHE_KEY }}-install
+    - name: Build double-conversion
+      if: ${{ steps.paths.outputs.double-conversion_SOURCE && ! steps.restore_double-conversion.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests double-conversion
+    - name: Save double-conversion to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.double-conversion_SOURCE && ! steps.restore_double-conversion.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.double-conversion_INSTALL }}
+       key: ${{ steps.paths.outputs.double-conversion_CACHE_KEY }}-install
+    - name: Restore fast_float from cache
+      id: restore_fast_float
+      if: ${{ steps.paths.outputs.fast_float_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.fast_float_INSTALL }}
+       key: ${{ steps.paths.outputs.fast_float_CACHE_KEY }}-install
+    - name: Build fast_float
+      if: ${{ steps.paths.outputs.fast_float_SOURCE && ! steps.restore_fast_float.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests fast_float
+    - name: Save fast_float to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.fast_float_SOURCE && ! steps.restore_fast_float.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.fast_float_INSTALL }}
+       key: ${{ steps.paths.outputs.fast_float_CACHE_KEY }}-install
+    - name: Restore fmt from cache
+      id: restore_fmt
+      if: ${{ steps.paths.outputs.fmt_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.fmt_INSTALL }}
+       key: ${{ steps.paths.outputs.fmt_CACHE_KEY }}-install
+    - name: Build fmt
+      if: ${{ steps.paths.outputs.fmt_SOURCE && ! steps.restore_fmt.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests fmt
+    - name: Save fmt to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.fmt_SOURCE && ! steps.restore_fmt.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.fmt_INSTALL }}
+       key: ${{ steps.paths.outputs.fmt_CACHE_KEY }}-install
+    - name: Restore gflags from cache
+      id: restore_gflags
+      if: ${{ steps.paths.outputs.gflags_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.gflags_INSTALL }}
+       key: ${{ steps.paths.outputs.gflags_CACHE_KEY }}-install
+    - name: Build gflags
+      if: ${{ steps.paths.outputs.gflags_SOURCE && ! steps.restore_gflags.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests gflags
+    - name: Save gflags to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.gflags_SOURCE && ! steps.restore_gflags.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.gflags_INSTALL }}
+       key: ${{ steps.paths.outputs.gflags_CACHE_KEY }}-install
+    - name: Restore glog from cache
+      id: restore_glog
+      if: ${{ steps.paths.outputs.glog_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.glog_INSTALL }}
+       key: ${{ steps.paths.outputs.glog_CACHE_KEY }}-install
+    - name: Build glog
+      if: ${{ steps.paths.outputs.glog_SOURCE && ! steps.restore_glog.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests glog
+    - name: Save glog to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.glog_SOURCE && ! steps.restore_glog.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.glog_INSTALL }}
+       key: ${{ steps.paths.outputs.glog_CACHE_KEY }}-install
+    - name: Restore googletest from cache
+      id: restore_googletest
+      if: ${{ steps.paths.outputs.googletest_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.googletest_INSTALL }}
+       key: ${{ steps.paths.outputs.googletest_CACHE_KEY }}-install
+    - name: Build googletest
+      if: ${{ steps.paths.outputs.googletest_SOURCE && ! steps.restore_googletest.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests googletest
+    - name: Save googletest to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.googletest_SOURCE && ! steps.restore_googletest.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.googletest_INSTALL }}
+       key: ${{ steps.paths.outputs.googletest_CACHE_KEY }}-install
+    - name: Restore libdwarf from cache
+      id: restore_libdwarf
+      if: ${{ steps.paths.outputs.libdwarf_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.libdwarf_INSTALL }}
+       key: ${{ steps.paths.outputs.libdwarf_CACHE_KEY }}-install
+    - name: Build libdwarf
+      if: ${{ steps.paths.outputs.libdwarf_SOURCE && ! steps.restore_libdwarf.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests libdwarf
+    - name: Save libdwarf to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.libdwarf_SOURCE && ! steps.restore_libdwarf.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.libdwarf_INSTALL }}
+       key: ${{ steps.paths.outputs.libdwarf_CACHE_KEY }}-install
+    - name: Restore lz4 from cache
+      id: restore_lz4
+      if: ${{ steps.paths.outputs.lz4_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.lz4_INSTALL }}
+       key: ${{ steps.paths.outputs.lz4_CACHE_KEY }}-install
+    - name: Build lz4
+      if: ${{ steps.paths.outputs.lz4_SOURCE && ! steps.restore_lz4.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests lz4
+    - name: Save lz4 to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.lz4_SOURCE && ! steps.restore_lz4.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.lz4_INSTALL }}
+       key: ${{ steps.paths.outputs.lz4_CACHE_KEY }}-install
+    - name: Restore jom from cache
+      id: restore_jom
+      if: ${{ steps.paths.outputs.jom_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.jom_INSTALL }}
+       key: ${{ steps.paths.outputs.jom_CACHE_KEY }}-install
+    - name: Build jom
+      if: ${{ steps.paths.outputs.jom_SOURCE && ! steps.restore_jom.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests jom
+    - name: Save jom to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.jom_SOURCE && ! steps.restore_jom.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.jom_INSTALL }}
+       key: ${{ steps.paths.outputs.jom_CACHE_KEY }}-install
+    - name: Restore perl from cache
+      id: restore_perl
+      if: ${{ steps.paths.outputs.perl_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.perl_INSTALL }}
+       key: ${{ steps.paths.outputs.perl_CACHE_KEY }}-install
+    - name: Build perl
+      if: ${{ steps.paths.outputs.perl_SOURCE && ! steps.restore_perl.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests perl
+    - name: Save perl to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.perl_SOURCE && ! steps.restore_perl.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.perl_INSTALL }}
+       key: ${{ steps.paths.outputs.perl_CACHE_KEY }}-install
+    - name: Restore openssl from cache
+      id: restore_openssl
+      if: ${{ steps.paths.outputs.openssl_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.openssl_INSTALL }}
+       key: ${{ steps.paths.outputs.openssl_CACHE_KEY }}-install
+    - name: Build openssl
+      if: ${{ steps.paths.outputs.openssl_SOURCE && ! steps.restore_openssl.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests openssl
+    - name: Save openssl to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.openssl_SOURCE && ! steps.restore_openssl.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.openssl_INSTALL }}
+       key: ${{ steps.paths.outputs.openssl_CACHE_KEY }}-install
+    - name: Restore snappy from cache
+      id: restore_snappy
+      if: ${{ steps.paths.outputs.snappy_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.snappy_INSTALL }}
+       key: ${{ steps.paths.outputs.snappy_CACHE_KEY }}-install
+    - name: Build snappy
+      if: ${{ steps.paths.outputs.snappy_SOURCE && ! steps.restore_snappy.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests snappy
+    - name: Save snappy to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.snappy_SOURCE && ! steps.restore_snappy.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.snappy_INSTALL }}
+       key: ${{ steps.paths.outputs.snappy_CACHE_KEY }}-install
+    - name: Restore zlib from cache
+      id: restore_zlib
+      if: ${{ steps.paths.outputs.zlib_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.zlib_INSTALL }}
+       key: ${{ steps.paths.outputs.zlib_CACHE_KEY }}-install
+    - name: Build zlib
+      if: ${{ steps.paths.outputs.zlib_SOURCE && ! steps.restore_zlib.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests zlib
+    - name: Save zlib to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.zlib_SOURCE && ! steps.restore_zlib.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.zlib_INSTALL }}
+       key: ${{ steps.paths.outputs.zlib_CACHE_KEY }}-install
+    - name: Restore zstd from cache
+      id: restore_zstd
+      if: ${{ steps.paths.outputs.zstd_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.zstd_INSTALL }}
+       key: ${{ steps.paths.outputs.zstd_CACHE_KEY }}-install
+    - name: Build zstd
+      if: ${{ steps.paths.outputs.zstd_SOURCE && ! steps.restore_zstd.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests zstd
+    - name: Save zstd to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.zstd_SOURCE && ! steps.restore_zstd.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.zstd_INSTALL }}
+       key: ${{ steps.paths.outputs.zstd_CACHE_KEY }}-install
+    - name: Restore libevent from cache
+      id: restore_libevent
+      if: ${{ steps.paths.outputs.libevent_SOURCE }}
+      uses: actions/cache/restore@v4
+      with:
+       path: ${{ steps.paths.outputs.libevent_INSTALL }}
+       key: ${{ steps.paths.outputs.libevent_CACHE_KEY }}-install
+    - name: Build libevent
+      if: ${{ steps.paths.outputs.libevent_SOURCE && ! steps.restore_libevent.outputs.cache-hit }}
+      run: python build/fbcode_builder/getdeps.py build --free-up-disk --no-tests libevent
+    - name: Save libevent to cache
+      uses: actions/cache/save@v4
+      if: ${{ steps.paths.outputs.libevent_SOURCE && ! steps.restore_libevent.outputs.cache-hit }}
+      with:
+       path: ${{ steps.paths.outputs.libevent_INSTALL }}
+       key: ${{ steps.paths.outputs.libevent_CACHE_KEY }}-install
+    - name: Build folly
+      run: python build/fbcode_builder/getdeps.py build --src-dir=. folly
+    - name: Copy artifacts
+      run: python build/fbcode_builder/getdeps.py fixup-dyn-deps --src-dir=. folly _artifacts/windows --final-install-prefix /usr/local
+    - uses: actions/upload-artifact@v6
+      with:
+        name: folly
+        path: _artifacts
+    - name: Test folly
+      run: python build/fbcode_builder/getdeps.py test --src-dir=. folly
diff --git a/build/fbcode_builder/getdeps/builder.py b/build/fbcode_builder/getdeps/builder.py
index 2e7ba2e58d8..4bcbd6b5926 100644
--- a/build/fbcode_builder/getdeps/builder.py
+++ b/build/fbcode_builder/getdeps/builder.py
@@ -92,7 +92,8 @@ def _get_cmd_prefix(self) -> list[str]:
                 wrapper = os.path.join(self.build_dir, "succeed.bat")
                 with open(wrapper, "w") as f:
                     f.write("@echo off\n")
-                    f.write(f'call "{vcvarsall}" amd64\n')
+                    arch = "arm64" if self.build_opts.is_arm() else "amd64"
+                    f.write(f'call "{vcvarsall}" {arch}\n')
                     f.write("set ERRORLEVEL=0\n")
                     f.write("exit /b 0\n")
                 return [wrapper, "&&"]
@@ -1421,7 +1422,7 @@ def _build(self, reconfigure: bool) -> None:
             # jom is compatible with nmake, adds the /j argument for parallel build
             make = "jom.exe"
             make_j_args = ["/j%s" % self.num_jobs]
-            args = ["VC-WIN64A-masm", "-utf-8"]
+            args = ["VC-WIN64-ARM", "-utf-8"] if self.build_opts.is_arm() else ["VC-WIN64A-masm", "-utf-8"]
             # fixes "if multiple CL.EXE write to the same .PDB file, please use /FS"
             extra_args = ["/FS"]
         elif self.build_opts.is_darwin():
@@ -1498,6 +1499,13 @@ def __init__(
 
     def _build(self, reconfigure: bool) -> None:
         env = self._compute_env()
+        if self.build_opts.is_arm():
+            if not self.b2_args:
+                self.b2_args = []
+            self.b2_args += [
+                "pch=off",
+                "context-impl=winfib",
+            ]
         linkage: list[str] = ["static"]
         if self.build_opts.is_windows() or self.build_opts.shared_libs:
             linkage.append("shared")
@@ -1517,7 +1525,10 @@ def _build(self, reconfigure: bool) -> None:
             if self.build_opts.is_windows():
                 bootstrap = os.path.join(self.src_dir, "bootstrap.bat")
                 self._check_cmd([bootstrap] + bootstrap_args, cwd=self.src_dir, env=env)
-                args += ["address-model=64"]
+                if self.build_opts.is_arm():
+                    args += ["address-model=64", "architecture=arm"]
+                else:
+                    args += ["address-model=64"]
             else:
                 bootstrap = os.path.join(self.src_dir, "bootstrap.sh")
                 self._check_cmd(
@@ -1526,6 +1537,19 @@ def _build(self, reconfigure: bool) -> None:
                     env=env,
                 )
 
+            b2_args = list(self.b2_args)
+            if self.build_opts.is_arm():
+                ARM_EXCLUDED_LIBS = {
+                    "coroutine",
+                    "graph",
+                    "graph_parallel",
+                    "mpi",
+                    "python",
+                }
+                b2_args = [
+                    arg for arg in b2_args
+                    if not any(arg == f"--with-{lib}" for lib in ARM_EXCLUDED_LIBS)
+                ]
             b2 = os.path.join(self.src_dir, "b2")
             self._check_cmd(
                 [
@@ -1535,7 +1559,7 @@ def _build(self, reconfigure: bool) -> None:
                     "--builddir=%s" % self.build_dir,
                 ]
                 + args
-                + self.b2_args
+                + b2_args
                 + [
                     "link=%s" % link,
                     "runtime-link=shared",
diff --git a/build/fbcode_builder/getdeps/buildopts.py b/build/fbcode_builder/getdeps/buildopts.py
index 435cce5951a..659d98f55fa 100644
--- a/build/fbcode_builder/getdeps/buildopts.py
+++ b/build/fbcode_builder/getdeps/buildopts.py
@@ -330,7 +330,9 @@ def compute_env_for_install_dirs(
                 "xplat/third-party/yarn/",
                 yarn_exe,
             )
-            node_exe = "node-win-x64.exe" if self.is_windows() else "node"
+            node_exe = "node"
+            if self.is_windows():
+                node_exe = "node-win-arm64.exe" if self.is_arm() else "node-win-x64.exe"
             env["NODE_BIN"] = os.path.join(
                 # pyre-fixme[6]: For 1st argument expected `LiteralString` but got
                 #  `Optional[str]`.
diff --git a/build/fbcode_builder/getdeps/platform.py b/build/fbcode_builder/getdeps/platform.py
index cae49d3dcb4..aa8bfde157e 100644
--- a/build/fbcode_builder/getdeps/platform.py
+++ b/build/fbcode_builder/getdeps/platform.py
@@ -195,7 +195,7 @@ def is_current_host_arm() -> bool:
         return "ARM64" in os.uname().version
     else:
         machine = platform.machine().lower()
-        return "arm" in machine or "aarch" in machine
+        return "arm" in machine or "aarch" in machine or "arm64" in machine
 
 
 class HostType:
diff --git a/folly/Portability.h b/folly/Portability.h
index d76900b0a5b..be6f7f87242 100644
--- a/folly/Portability.h
+++ b/folly/Portability.h
@@ -108,7 +108,7 @@ constexpr bool kHasUnalignedAccess = false;
 #define FOLLY_ARM 0
 #endif
 
-#if defined(__aarch64__)
+#if defined(__aarch64__) || defined(_M_ARM64)
 #define FOLLY_AARCH64 1
 #else
 #define FOLLY_AARCH64 0
@@ -361,7 +361,7 @@ constexpr auto kHasWeakSymbols = false;
   (FOLLY_SSE > major || FOLLY_SSE == major && FOLLY_SSE_MINOR >= minor)
 
 #ifndef FOLLY_NEON
-#if (defined(__ARM_NEON) || defined(__ARM_NEON__)) && !defined(__CUDACC__)
+#if (defined(__ARM_NEON) || defined(__ARM_NEON__) || defined(_M_ARM64)) && !defined(__CUDACC__)
 #define FOLLY_NEON 1
 #else
 #define FOLLY_NEON 0
@@ -646,6 +646,10 @@ constexpr auto kCpplibVer = 0;
 #if defined(__NVCC__)
 // For now, NVCC matches other compilers but does not offer coroutines.
 #define FOLLY_HAS_COROUTINES 0
+#elif defined(_MSC_VER) && defined(_M_ARM64)
+// MSVC ARM64: coroutine codegen triggers unsupported relocations at link time,
+// leading to build failures. Disable coroutines for this target.
+#define FOLLY_HAS_COROUTINES 0
 #elif defined(_WIN32) && defined(__clang__) && !defined(LLVM_COROUTINES) && \
     !defined(LLVM_COROUTINES_CPP20)
 // LLVM and MSVC coroutines are ABI incompatible, so for the MSVC implementation
diff --git a/folly/algorithm/simd/Movemask.h b/folly/algorithm/simd/Movemask.h
index eec9ee1d5bc..ad30e627587 100644
--- a/folly/algorithm/simd/Movemask.h
+++ b/folly/algorithm/simd/Movemask.h
@@ -146,13 +146,13 @@ FOLLY_ERASE auto movemaskChars16Aarch64(uint8x16_t reg) {
   return std::pair{bits, std::integral_constant<std::uint32_t, 4>{}};
 }
 
-template <typename Reg>
+template <typename Scalar, typename Reg>
 FOLLY_ERASE uint64x1_t asUint64x1Aarch64(Reg reg) {
-  if constexpr (std::is_same_v<Reg, uint64x1_t>) {
+  if constexpr (sizeof(Scalar) == 8) {
     return reg;
-  } else if constexpr (std::is_same_v<Reg, uint32x2_t>) {
+  } else if constexpr (sizeof(Scalar) == 4) {
     return vreinterpret_u64_u32(reg);
-  } else if constexpr (std::is_same_v<Reg, uint16x4_t>) {
+  } else if constexpr (sizeof(Scalar) == 2) {
     return vreinterpret_u64_u16(reg);
   } else {
     return vreinterpret_u64_u8(reg);
@@ -164,16 +164,18 @@ FOLLY_ERASE uint64x1_t asUint64x1Aarch64(Reg reg) {
 template <typename Scalar>
 template <typename Reg>
 FOLLY_ERASE auto movemask_fn<Scalar>::operator()(Reg reg) const {
-  if constexpr (std::is_same_v<Reg, uint64x2_t>) {
-    return movemask<std::uint32_t>(vmovn_u64(reg));
-  } else if constexpr (std::is_same_v<Reg, uint32x4_t>) {
-    return movemask<std::uint16_t>(vmovn_u32(reg));
-  } else if constexpr (std::is_same_v<Reg, uint16x8_t>) {
-    return movemask<std::uint8_t>(vmovn_u16(reg));
-  } else if constexpr (std::is_same_v<Reg, uint8x16_t>) {
-    return detail::movemaskChars16Aarch64(reg);
+  if constexpr (sizeof(Reg) == 16) {
+    if constexpr (sizeof(Scalar) == 1) {
+      return detail::movemaskChars16Aarch64(reg);
+    } else if constexpr (sizeof(Scalar) == 2) {
+      return movemask<std::uint8_t>(vmovn_u16(reg));
+    } else if constexpr (sizeof(Scalar) == 4) {
+      return movemask<std::uint16_t>(vmovn_u32(reg));
+    } else {
+      return movemask<std::uint32_t>(vmovn_u64(reg));
+    }
   } else {
-    std::uint64_t mmask = vget_lane_u64(detail::asUint64x1Aarch64(reg), 0);
+    std::uint64_t mmask = vget_lane_u64(detail::asUint64x1Aarch64<Scalar>(reg), 0);
     return std::pair{
         mmask, std::integral_constant<std::uint32_t, sizeof(Scalar) * 8>{}};
   }
diff --git a/folly/algorithm/simd/find_first_of.h b/folly/algorithm/simd/find_first_of.h
index 5b099c1455d..3ddd3d2ba29 100644
--- a/folly/algorithm/simd/find_first_of.h
+++ b/folly/algorithm/simd/find_first_of.h
@@ -277,8 +277,8 @@ class default_vector_finder_first_op_of {
             vld1q_u8(reinterpret_cast<uint8_t const*>(input.data() + size));
         auto vmask = vdupq_n_u8(Eq ? 0 : -1);
         for (auto const a : alphabet_) {
-          auto const veq = vhaystack == vdupq_n_u8(a);
-          vmask = Eq ? veq | vmask : ~veq & vmask;
+            auto const veq = vceqq_u8(vhaystack, vdupq_n_u8(static_cast<uint8_t>(a)));
+            vmask = Eq ? vorrq_u8(veq, vmask) : vbicq_u8(vmask, veq);
         }
 #endif
         if (auto const [word, bits] = movemask<CharT>(vmask); word) {
@@ -398,10 +398,12 @@ class shuffle_vector_finder_first_op_of {
         auto const vtable = reinterpret_cast<uint8x16_t const*>(table);
         auto const vhaystack =
             vld1q_u8(reinterpret_cast<uint8_t const*>(input.data() + size));
+        auto const vhaystack_lo = vandq_u8(vhaystack, vdupq_n_u8(15));
         auto vmask = vdupq_n_u8(Eq ? 0 : -1);
         for (size_t i = 0; i < shuffle_.rounds; ++i) {
-          auto const veq = vqtbl1q_u8(vtable[i], vhaystack & 15) == vhaystack;
-          vmask = Eq ? veq | vmask : ~veq & vmask;
+            auto const vshuffle = vqtbl1q_u8(vtable[i], vhaystack_lo);
+            auto const veq = vceqq_u8(vshuffle, vhaystack);
+            vmask = Eq ? vorrq_u8(veq, vmask) : vbicq_u8(vmask, veq);
         }
 #endif
         if (auto const [word, bits] = movemask<CharT>(vmask); word) {
diff --git a/folly/chrono/Hardware.h b/folly/chrono/Hardware.h
index 4f41ad62480..a5f9d3afefe 100644
--- a/folly/chrono/Hardware.h
+++ b/folly/chrono/Hardware.h
@@ -43,7 +43,7 @@ inline std::uint64_t hardware_timestamp() {
   return __rdtsc();
 #elif defined(__GNUC__) && (defined(__i386__) || FOLLY_X64)
   return __builtin_ia32_rdtsc();
-#elif FOLLY_AARCH64 && !FOLLY_MOBILE
+#elif FOLLY_AARCH64 && !FOLLY_MOBILE && !defined(_MSC_VER)
   uint64_t cval;
   asm volatile("mrs %0, cntvct_el0" : "=r"(cval));
   return cval;
diff --git a/folly/compression/Instructions.h b/folly/compression/Instructions.h
index 0e7c8937401..06af6d75397 100644
--- a/folly/compression/Instructions.h
+++ b/folly/compression/Instructions.h
@@ -18,7 +18,9 @@
 
 #include <glog/logging.h>
 
-#ifdef _MSC_VER
+#if defined(_MSC_VER) && defined(_M_ARM64)
+#include <intrin.h>
+#elif defined(_MSC_VER)
 #include <immintrin.h>
 #endif
 
@@ -45,15 +47,31 @@ struct Default {
   static std::string_view name() noexcept { return "Default"; }
   static bool supported(const folly::CpuId& /* cpuId */ = {}) { return true; }
   static FOLLY_ALWAYS_INLINE uint64_t popcount(uint64_t value) {
+  #if defined(_MSC_VER) && defined(_M_ARM64)
+    return uint64_t(__popcnt64(value));
+  #else
     return uint64_t(__builtin_popcountll(value));
+  #endif
   }
   static FOLLY_ALWAYS_INLINE int ctz(uint64_t value) {
     DCHECK_GT(value, 0u);
-    return __builtin_ctzll(value);
+    #if defined(_MSC_VER) && defined(_M_ARM64)
+      unsigned long index;
+      _BitScanForward64(&index, value);
+      return int(index);
+    #else
+      return __builtin_ctzll(value);
+    #endif
   }
   static FOLLY_ALWAYS_INLINE int clz(uint64_t value) {
     DCHECK_GT(value, 0u);
-    return __builtin_clzll(value);
+    #if defined(_MSC_VER) && defined(_M_ARM64)
+      unsigned long index;
+      _BitScanReverse64(&index, value);
+      return 63 - int(index);
+    #else
+      return __builtin_clzll(value);
+    #endif
   }
   static FOLLY_ALWAYS_INLINE uint64_t blsr(uint64_t value) {
     return value & (value - 1);
diff --git a/folly/container/detail/F14Table.h b/folly/container/detail/F14Table.h
index 69887e2ec8b..3bdd077688b 100644
--- a/folly/container/detail/F14Table.h
+++ b/folly/container/detail/F14Table.h
@@ -338,7 +338,13 @@ std::pair<std::size_t, std::size_t> splitHashImpl(std::size_t hash) {
     // was 48 bytes of assembly (even after using the same multiplicand
     // for both steps) and this one was 27 bytes, for example.
     auto const kMul = 0xc4ceb9fe1a85ec53ULL;
-#ifdef _WIN32
+#if defined(_MSC_VER) && defined(_M_ARM64)
+    // MSVC ARM64: no _mul128, no __int128.
+    // Use 32-bit halves to compute the 128-bit product manually.
+    uint64_t lo = hash * kMul;
+    // __umulh gives the high 64 bits of an unsigned 64x64 multiply
+    uint64_t hi = __umulh(hash, kMul);
+#elif defined(_WIN32) && !defined(FOLLY_AARCH64)
     __int64 signedHi;
     __int64 signedLo = _mul128(
         static_cast<__int64>(hash), static_cast<__int64>(kMul), &signedHi);
diff --git a/folly/fibers/BoostContextCompatibility.h b/folly/fibers/BoostContextCompatibility.h
index 310c4d13c77..30b04251347 100644
--- a/folly/fibers/BoostContextCompatibility.h
+++ b/folly/fibers/BoostContextCompatibility.h
@@ -16,17 +16,127 @@
 
 #pragma once
 
-#include <boost/context/detail/fcontext.hpp>
 #include <glog/logging.h>
+#include <folly/Function.h>
 
 /**
  * Wrappers for different versions of boost::context library
  * API reference for different versions
  * Boost 1.61:
  * https://github.com/boostorg/context/blob/boost-1.61.0/include/boost/context/detail/fcontext.hpp
+ *
+ * On Windows ARM64, boost::context assembly stubs (jump_fcontext / make_fcontext)
+ * are not currently supported, so fall back to the native Windows Fibers API.
  */
 
-#include <folly/Function.h>
+#if defined(_WIN32) && defined(_M_ARM64)
+
+#ifndef NOMINMAX
+#define NOMINMAX
+#endif
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#include <windows.h>
+
+namespace folly {
+namespace fibers {
+
+class FiberImpl {
+ public:
+  FiberImpl(
+      folly::Function<void()> func,
+      unsigned char* /*stackLimit*/,
+      size_t stackSize)
+      : func_(std::move(func)) {
+    fiber_ = CreateFiberEx(
+    stackSize,             
+    stackSize,            
+    FIBER_FLAG_FLOAT_SWITCH,
+    &FiberImpl::fiberFunc,
+    this);
+    CHECK(fiber_ != nullptr)
+    << "CreateFiberEx failed: " << GetLastError();
+  }
+
+  ~FiberImpl() {
+      if (fiber_) {
+          DCHECK(GetCurrentFiber() != fiber_)
+              << "Destroying fiber while it is active";
+          DeleteFiber(std::exchange(fiber_, nullptr));
+      }
+  }
+
+  FiberImpl(const FiberImpl&) = delete;
+  FiberImpl& operator=(const FiberImpl&) = delete;
+
+  FiberImpl(FiberImpl&& other) noexcept
+      : func_(std::move(other.func_)),
+        fiber_(std::exchange(other.fiber_, nullptr)),
+        mainFiber_(std::exchange(other.mainFiber_, nullptr)),
+        convertedThread_(std::exchange(other.convertedThread_, false)) {}
+
+  FiberImpl& operator=(FiberImpl&& other) noexcept {
+    if (this != &other) {
+      if (fiber_) DeleteFiber(fiber_);
+      func_ = std::move(other.func_);
+      fiber_ = std::exchange(other.fiber_, nullptr);
+      mainFiber_ = std::exchange(other.mainFiber_, nullptr);
+      convertedThread_ = std::exchange(other.convertedThread_, false);
+    }
+    return *this;
+  }
+
+  void activate() {
+      mainFiber_ = GetCurrentFiber();
+      // On ARM64 Windows, GetCurrentFiber() returns a garbage low address
+      // (e.g. 0x1E00) when the thread has not been converted to a fiber yet.
+      // A real fiber handle is always above 64KB (Windows minimum allocation
+      // granularity), so use 0x10000 as the threshold.
+      if (mainFiber_ == nullptr ||
+          mainFiber_ == INVALID_HANDLE_VALUE ||
+          reinterpret_cast<uintptr_t>(mainFiber_) < 0x10000) {
+          mainFiber_ = ConvertThreadToFiber(nullptr);
+          CHECK(mainFiber_ != nullptr)
+              << "ConvertThreadToFiber failed: " << GetLastError();
+          convertedThread_ = true;
+      }
+      SwitchToFiber(fiber_);
+  }
+
+
+  void deactivate() {
+    DCHECK(mainFiber_ != nullptr) << "deactivate() called before activate()";
+    SwitchToFiber(std::exchange(mainFiber_, nullptr));
+    if (convertedThread_) {
+        ConvertFiberToThread();
+        convertedThread_ = false;
+    }
+  }
+
+  void* getStackPointer() const { return nullptr; }
+
+ private:
+  static VOID CALLBACK fiberFunc(LPVOID param) {
+    auto* self = static_cast<FiberImpl*>(param);
+    self->func_();
+    // func_() must not return in normal folly::fibers usage.
+    // If it does, switch back to avoid undefined behavior — but
+    // don't call deactivate() as mainFiber_ may already be cleared.
+    CHECK(false) << "FiberImpl::func_() returned unexpectedly";
+  }
+
+  folly::Function<void()> func_;
+  LPVOID fiber_{nullptr};
+  LPVOID mainFiber_{nullptr};
+  bool convertedThread_{false};
+};
+
+} // namespace fibers
+} // namespace folly
+#else
+
+#include <boost/context/detail/fcontext.hpp>
 
 namespace folly {
 namespace fibers {
@@ -110,3 +220,4 @@ class FiberImpl {
 };
 } // namespace fibers
 } // namespace folly
+#endif
diff --git a/folly/lang/Bits.h b/folly/lang/Bits.h
index 3043f0f3d0f..8a33c71205c 100644
--- a/folly/lang/Bits.h
+++ b/folly/lang/Bits.h
@@ -67,6 +67,10 @@
 #include <folly/lang/CString.h>
 #include <folly/portability/Builtins.h>
 
+#if defined(_MSC_VER) && defined(_M_ARM64) 
+#include <intrin.h>
+#endif
+
 #ifdef __BMI2__
 #include <immintrin.h>
 #endif
@@ -183,14 +187,22 @@ inline constexpr T extractFirstSet(T const v) {
 /// Returns the number of bits which are set.
 template <typename T>
 inline constexpr unsigned int popcount(T const v) {
-  using U0 = unsigned int;
-  using U1 = unsigned long int;
   using U2 = unsigned long long int;
   using detail::bits_to_unsigned;
   static_assert(sizeof(T) <= sizeof(U2), "over-sized type");
   static_assert(std::is_integral<T>::value, "non-integral type");
   static_assert(!std::is_same<T, bool>::value, "bool type");
 
+#if defined(_MSC_VER) && defined(_M_ARM64) 
+  // For MSVC ARM64 use __popcnt intrinsics.
+  return static_cast<unsigned int>(
+      sizeof(T) <= sizeof(unsigned int) ?
+        __popcnt(bits_to_unsigned<unsigned int>(v))
+        : __popcnt64(bits_to_unsigned<unsigned long long>(v))
+      );
+#else
+  using U0 = unsigned int;
+  using U1 = unsigned long int;
   // clang-format off
   return static_cast<unsigned int>(
       sizeof(T) <= sizeof(U0) ? __builtin_popcount(bits_to_unsigned<U0>(v)) :
@@ -198,6 +210,7 @@ inline constexpr unsigned int popcount(T const v) {
       sizeof(T) <= sizeof(U2) ? __builtin_popcountll(bits_to_unsigned<U2>(v)) :
       0);
   // clang-format on
+#endif
 }
 
 template <class T>
diff --git a/folly/portability/Asm.h b/folly/portability/Asm.h
index 5f850163e30..a5637bdf4a4 100644
--- a/folly/portability/Asm.h
+++ b/folly/portability/Asm.h
@@ -36,6 +36,8 @@ inline void asm_volatile_memory() {
 inline void asm_volatile_pause() {
 #if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
   ::_mm_pause();
+#elif defined(_MSC_VER) && defined(_M_ARM64)
+  __yield();
 #elif defined(__i386__) || FOLLY_X64 || \
     (defined(__mips_isa_rev) && __mips_isa_rev > 1)
   asm volatile("pause");