Add initial Windows support

Author: 0xDELUXA

CMakeLists.txt

@@ -24,7 +24,9 @@ include(TableGen)
 include(AddLLVM)
 include(AddMLIR)
 include(HandleLLVMOptions)
-string(REPLACE "-Wl,-z,defs" "" CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS}")
+if(NOT WIN32)
+  string(REPLACE "-Wl,-z,defs" "" CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS}")
+endif()
 include(MLIRDetectPythonEnv)
 mlir_configure_python_dev_packages()
 
@@ -45,6 +47,22 @@ set(MLIR_PYTHON_PACKAGE_PREFIX "_mlir" CACHE STRING "" FORCE)
 set(MLIR_BINDINGS_PYTHON_INSTALL_PREFIX "python_packages/flydsl/${MLIR_PYTHON_PACKAGE_PREFIX}" CACHE STRING "" FORCE)
 
 
+# On Windows, MLIR's default SelfOwningTypeID scheme does not work across DLL
+# boundaries: the TypeID's `static SelfOwningTypeID id` member cannot be auto-imported
+# from a DLL without explicit __declspec(dllimport). So FlyDSL's Fly-defined types
+# (defined in obj.MLIRFlyDialect embedded in FlyPythonCAPI.dll) are unreachable from
+# .pyd extensions that reference them, causing link errors or runtime TypeID mismatches.
+#
+# Switch our compilation to string-based FallbackTypeIDs globally. Our own types all
+# route through the process-shared `registerImplicitTypeID` exported from
+# FlyPythonCAPI.dll, giving consistent TypeIDs across every DLL. Upstream MLIR's
+# prebuilt static libs (MLIRIR.lib, etc.) were compiled with SelfOwning TypeIDs,
+# but those are now linked into FlyPythonCAPI.dll as a single copy — internal usage
+# within that DLL still agrees with itself, so no mismatch there.
+if(WIN32)
+  add_compile_definitions(MLIR_USE_FALLBACK_TYPE_IDS=1)
+endif()
+
 add_subdirectory(include/flydsl)
 add_subdirectory(lib)
 add_subdirectory(tools)

docs/windows_build_guide.md

@@ -0,0 +1,144 @@
+# FlyDSL on Windows (experimental)
+
+This guide covers building and running FlyDSL natively on Windows. The Windows
+port uses the **TheRock ROCm SDK** (installed as a Python package into a venv)
+rather than a system-wide ROCm install.
+
+> **Status**: experimental. 301 / 310 unit tests pass (97%). See
+> [Known limitations](#known-limitations) for what doesn't yet.
+
+## Prerequisites
+
+1. **Windows 10/11, x64** with an AMD GPU supported by ROCm. Tested on RDNA4 (`gfx1200`, Radeon RX 9060 XT).
+2. **Visual Studio 2022 Build Tools** (or full VS 2022) with the *Desktop
+   development with C++* workload — provides the MSVC toolchain.
+3. **LLVM/Clang** in PATH — `clang-cl`, `llvm-ar`, `llvm-ml`, `lld-link`. The
+   official LLVM Windows installer puts these on PATH.
+4. **Ninja** in PATH (`choco install ninja` or bundled with VS).
+5. **Git** in PATH.
+6. **Python 3.12** (the build has only been exercised against 3.12).
+7. **PowerShell 5.1+** (ships with Windows).
+
+All commands below assume you're running in a **Developer PowerShell / x64
+Native Tools Command Prompt**, or have run `vcvarsall.bat amd64` first so that
+`cl.exe`/`link.exe` are on PATH.
+
+## 1. Create a venv and install TheRock ROCm SDK
+
+TheRock ships ROCm as a Python wheel that installs into your venv. FlyDSL on
+Windows currently expects this layout (it finds `ld.lld.exe`, OCML bitcode,
+and `amdhip64_7.dll` relative to the SDK root).
+
+```powershell
+python -m venv C:\path\to\flydsl-venv
+C:\path\to\flydsl-venv\Scripts\Activate.ps1
+
+# Install TheRock ROCm SDK for your GPU family and initialize. For RDNA4 / gfx1200:
+pip install --pre --index-url https://rocm.nightlies.amd.com/v2/gfx120X-all torch torchaudio torchvision rocm[libraries,devel]
+rocm-sdk init
+```
+
+After install, locate the SDK development root — typically:
+`...\flydsl-venv\Lib\site-packages\_rocm_sdk_devel`
+
+## 2. Set environment variables
+
+```powershell
+$env:ROCM_PATH = "C:\path\to\flydsl-venv\Lib\site-packages\_rocm_sdk_devel"
+# Optional: force a specific GPU arch when torch-rocm auto-detect isn't right.
+# $env:FLYDSL_GPU_ARCH = "gfx1200"
+```
+
+## 3. Build LLVM/MLIR
+
+This pins the commit from `thirdparty/llvm-hash.txt`, builds with Ninja +
+`clang-cl`, and installs into `..\llvm-project\mlir_install\`.
+
+```powershell
+# From the FlyDSL repo root:
+.\scripts\build_llvm.ps1 -Arch gfx1200 # substitute your GPU arch
+# or rely on FLYDSL_GPU_ARCH env var; default is gfx942.
+```
+
+Notes:
+- The script passes `/DMLIR_USE_FALLBACK_TYPE_IDS=1` globally — required to
+  make MLIR's TypeIDs work across multiple DLLs on Windows.
+- Build takes 30–60 min on a typical workstation. Use `-Jobs N` to cap
+  parallelism (default is `NUMBER_OF_PROCESSORS / 2`).
+- Output: `..\llvm-project\mlir_install\` — keep this around.
+
+## 4. Build FlyDSL
+
+```powershell
+$env:MLIR_PATH = "C:\llvm-project\mlir_install" # or wherever step 3 installed
+.\scripts\build.ps1
+```
+
+This produces `build-fly\python_packages\flydsl\` with the compiled extension
+modules, runtime DLLs, and python sources.
+
+## 5. Install FlyDSL into the venv
+
+```powershell
+pip install -e .
+```
+
+This runs `setup.py` which creates a directory junction from
+`python\flydsl\_mlir` → `build-fly\python_packages\flydsl\_mlir` (junction
+instead of symlink so no admin / Developer Mode required).
+
+## 6. Run tests
+
+```powershell
+$env:PYTHONPATH = "$PWD\build-fly\python_packages;$PWD"
+python -m pytest tests\unit\ -q
+```
+
+Expected: ~301 passed / ~4 failed / 5 skipped. See
+[Known limitations](#known-limitations).
+
+## How the Windows-specific bits work
+
+| Component | Linux behavior | Windows behavior |
+|---|---|---|
+| TypeID | `SelfOwningTypeID` (pointer identity across `.so`) | `MLIR_USE_FALLBACK_TYPE_IDS=1` — string-based, works across DLLs |
+| Symbol export | `-fvisibility=hidden` + version script | `WINDOWS_EXPORT_ALL_SYMBOLS` on `FlyPythonCAPI.dll`, with `obj.MLIRFlyDialect` / `obj.MLIRFlyROCDLDialect` added as direct sources and upstream `MLIRIR.lib` / `MLIRSupport.lib` extracted via `llvm-ar x` so auto-`.def` generation sees them |
+| lld for ROCDL | `<toolkit>/llvm/bin/ld.lld` — matches `/opt/rocm` layout | Staging junction at `%LOCALAPPDATA%\flydsl\rocm_toolkit\` unifies TheRock's `lib/llvm/bin/ld.lld.exe` + `lib/llvm/amdgcn/bitcode/` into the layout MLIR expects |
+| Runtime DLL search | `RPATH=$ORIGIN` | `os.add_dll_directory` + ctypes pre-load of `_mlir_libs\*.dll` before JIT engine init (LLVM's `LoadLibraryPermanently` doesn't search DLL-local dirs) |
+| GPU arch detect | `rocm_agent_enumerator` | Falls back to `torch.cuda.get_device_properties(0).gcnArchName` since TheRock doesn't ship the enumerator |
+| `_mlir` package link | Symlink | Directory junction (no admin needed) |
+
+## Known limitations
+
+- **Multi-stream correctness**: 2 `test_multi_stream_launch` tests fail
+  (`test_two_streams_independent`, `test_diamond_pipeline_with_event_sync`).
+  Single-stream launches work correctly.
+- **Disk cache test fragility**: `test_fp_math_reaches_pipeline` passes solo
+  but fails in-suite because cached compilation artifacts bypass the monkey-
+  patched hook. Not Windows-specific. Run with `FLYDSL_RUNTIME_ENABLE_CACHE=0`.
+- **Torch profiler test**: `test_cache_disabled_run_perftest_does_not_crash`
+  hits a `DataFrame.host_time_sum` attribute error inside torch.profiler —
+  version compat, not a FlyDSL issue.
+- **No CI coverage** yet — every build is verified manually.
+- **Only gfx1200 exercised** on Windows; other arches should work
+  if your TheRock SDK + GPU combination is supported.
+
+## Troubleshooting
+
+- **`MLIR_FOUND=FALSE` or `LLVMNVPTXCodeGen` missing at configure time**:
+  the ROCm SDK ships its own `LLVMConfig.cmake`. Ensure `-DLLVM_DIR=...` is
+  passed explicitly (the scripts do this). Don't add `_rocm_sdk_devel` to
+  `CMAKE_PREFIX_PATH`.
+- **`_ITERATOR_DEBUG_LEVEL` link mismatch**: you're building FlyDSL as Debug
+  while MLIR was built Release. Keep both at Release (`build.ps1` passes
+  `-DCMAKE_BUILD_TYPE=Release`).
+- **`ModuleNotFoundError: flydsl._mlir`**: the editable install junction
+  didn't get created. `cd` into the repo and run:
+  `New-Item -ItemType Junction -Path python\flydsl\_mlir -Target build-fly\python_packages\flydsl\_mlir`.
+- **`hipErrorNoBinaryForGpu`**: your kernel was compiled for the wrong arch.
+  Set `FLYDSL_GPU_ARCH` to the value printed by
+  `python -c "import torch; print(torch.cuda.get_device_properties(0).gcnArchName)"`.
+- **`rocm amdgcn bitcode path ... does not exist`** during compilation:
+  the toolkit staging junction failed. Check
+  `%LOCALAPPDATA%\flydsl\rocm_toolkit\amdgcn\bitcode\` and that `ROCM_PATH`
+  points at TheRock's `_rocm_sdk_devel`.

kernels/custom_all_reduce.py

@@ -130,8 +130,10 @@ def _get_gpu_arch(cls) -> str:
             pass
         if not arch:
             try:
+                import shutil
                 import subprocess
-                r = subprocess.run(["rocminfo"], capture_output=True, text=True, timeout=10)
+                rocminfo = shutil.which("rocminfo") or "rocminfo"
+                r = subprocess.run([rocminfo], capture_output=True, text=True, timeout=10)
                 for line in r.stdout.splitlines():
                     if "Name:" in line and "gfx" in line.lower():
                         arch = line.split(":")[-1].strip()
@@ -147,7 +149,13 @@ def _load_hip(cls):
         if cls._hip is not None:
             return cls._hip
         import ctypes
-        for name in ("libamdhip64.so", "libamdhip64.so.6", "libamdhip64.so.5"):
+        import sys
+
+        if sys.platform == "win32":
+            hip_candidates = ("amdhip64.dll", "amdhip64_7.dll", "amdhip64_6.dll")
+        else:
+            hip_candidates = ("libamdhip64.so", "libamdhip64.so.6", "libamdhip64.so.5")
+        for name in hip_candidates:
             try:
                 cls._hip = ctypes.CDLL(name)
                 break

lib/Bindings/Python/BindingUtils.h

@@ -4,9 +4,11 @@
 #ifndef FLYDSL_BINDINGS_PYTHON_BINDINGUTILS_H
 #define FLYDSL_BINDINGS_PYTHON_BINDINGUTILS_H
 
+// Nanobind.h must come before Interop.h: nanobind includes Python.h which
+// defines PyObject — Interop.h uses PyObject but doesn't include Python.h.
+#include "mlir/Bindings/Python/Nanobind.h"
 #include "mlir-c/Bindings/Python/Interop.h"
 #include "mlir/Bindings/Python/IRCore.h"
-#include "mlir/Bindings/Python/Nanobind.h"
 #include "mlir/Bindings/Python/NanobindAdaptors.h"
 #include "mlir/CAPI/IR.h"
 #include "mlir/CAPI/Support.h"

lib/CAPI/Dialect/Fly/CMakeLists.txt

@@ -1,5 +1,21 @@
-add_mlir_public_c_api_library(MLIRCPIFly
-  FlyDialect.cpp
-  LINK_LIBS PUBLIC
-  MLIRFlyDialect
-)
+# On Windows, MLIRFlyDialect's OBJECT files are added directly to FlyPythonCAPI
+# (see python/mlir_flydsl/CMakeLists.txt) so that WINDOWS_EXPORT_ALL_SYMBOLS exports
+# the mlir::fly::* C++ symbols. Linking MLIRFlyDialect here transitively would cause
+# duplicate-symbol errors at FlyPythonCAPI.dll link time.
+if(WIN32)
+  add_mlir_public_c_api_library(MLIRCPIFly
+    FlyDialect.cpp
+  )
+  # Still need to compile against the dialect's headers (TableGen'd types).
+  add_dependencies(obj.MLIRCPIFly MLIRFlyIncGen)
+  target_include_directories(obj.MLIRCPIFly PRIVATE
+    ${CMAKE_BINARY_DIR}/include
+    ${CMAKE_SOURCE_DIR}/include
+  )
+else()
+  add_mlir_public_c_api_library(MLIRCPIFly
+    FlyDialect.cpp
+    LINK_LIBS PUBLIC
+    MLIRFlyDialect
+  )
+endif()

lib/CAPI/Dialect/FlyROCDL/CMakeLists.txt

@@ -1,6 +1,23 @@
-add_mlir_public_c_api_library(MLIRCPIFlyROCDL
-  FlyROCDLDialect.cpp
-  LINK_LIBS PUBLIC
-  MLIRFlyROCDLDialect
-  MLIRFlyToROCDL
-)
+# On Windows, MLIRFlyROCDLDialect's OBJECT files are added directly to FlyPythonCAPI
+# so WINDOWS_EXPORT_ALL_SYMBOLS exports the C++ symbols. Avoid duplicate linkage here.
+# MLIRFlyToROCDL is still linked as a static lib — its symbols are only used through
+# the CAPI registerFlyToROCDLConversionPass wrapper, which IS in an embedded obj.
+if(WIN32)
+  add_mlir_public_c_api_library(MLIRCPIFlyROCDL
+    FlyROCDLDialect.cpp
+    LINK_LIBS PUBLIC
+    MLIRFlyToROCDL
+  )
+  add_dependencies(obj.MLIRCPIFlyROCDL MLIRFlyROCDLIncGen)
+  target_include_directories(obj.MLIRCPIFlyROCDL PRIVATE
+    ${CMAKE_BINARY_DIR}/include
+    ${CMAKE_SOURCE_DIR}/include
+  )
+else()
+  add_mlir_public_c_api_library(MLIRCPIFlyROCDL
+    FlyROCDLDialect.cpp
+    LINK_LIBS PUBLIC
+    MLIRFlyROCDLDialect
+    MLIRFlyToROCDL
+  )
+endif()