00531fb591
Building the `gpu` (OpenCL) backend on Windows no longer needs a vendor OpenCL SDK. `cl-sys` links `OpenCL` (#[link(name = "OpenCL")]); instead of requiring an SDK-provided OpenCL.lib, build.rs now generates a vendor-neutral import library at build time from windows/OpenCL.def (all 118 cl-sys exports) — lib.exe for MSVC (located via the cc crate), dlltool for MinGW — and puts it on the link search path. The real OpenCL.dll is supplied at runtime by the GPU driver. build.rs no-ops on non-Windows targets and when the gpu feature is off, and warns rather than panics if the toolchain tool is absent so `cargo check` still works. Combined with the runtime-loaded (dlopen) CUDA/NVML, a Windows build now needs zero external GPU libraries. Add BUILD-windows.md (toolchain, build, crt-static packaging, runtime deps, CI) and link it from the README. Verified the whole crate compiles for x86_64-pc-windows-gnu (default features and gpu,cuda); Linux is unaffected. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
120 lines
4.5 KiB
Markdown
120 lines
4.5 KiB
Markdown
# Building jackpotminer on Windows
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The miner builds on Windows with **no external GPU SDKs**. The CUDA driver and
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NVML are loaded at runtime (`dlopen`/`LoadLibrary`), and the OpenCL import
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library is generated at build time from `windows/OpenCL.def` — so you don't need
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the CUDA Toolkit, an OpenCL SDK, or any vendor libraries to compile. The whole
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codebase (miner + the `jackpotminer-config` GUI) is verified to compile for
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`x86_64-pc-windows-*`.
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## Prerequisites
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- **Rust** (https://rustup.rs). The default target is `x86_64-pc-windows-msvc`.
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- **MSVC build tools** — Visual Studio 2019/2022 or the standalone *Build Tools
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for Visual Studio* with the **“Desktop development with C++”** workload (gives
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`link.exe`, `lib.exe`, and the Windows SDK).
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- Build from a **“x64 Native Tools Command Prompt for VS”** (or any shell where
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the MSVC environment is active) so `lib.exe` is found. `cargo` also locates
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it automatically via the registry in most cases.
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- *(Alternative toolchain)* the GNU target `x86_64-pc-windows-gnu` works too,
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with **MinGW-w64** on `PATH` (provides `dlltool` and the linker).
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No CUDA Toolkit and **no OpenCL SDK** are required.
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## Build
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```powershell
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:: Default: OpenCL + CUDA backends + the GUI config tool
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cargo build --release
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:: Miner only (no GUI), both GPU backends
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cargo build --release --no-default-features --features gpu,cuda
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:: OpenCL only (AMD / Intel / NVIDIA)
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cargo build --release --no-default-features --features gpu
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:: NVIDIA only — needs nothing external at build time (CUDA is dlopen'd)
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cargo build --release --no-default-features --features cuda
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```
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Outputs: `target\release\jackpotminer.exe` (and `jackpotminer-config.exe` with
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the default features).
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### How the OpenCL build dependency is avoided
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`ocl`/`cl-sys` link `OpenCL` (`#[link(name = "OpenCL")]`), which normally needs
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an `OpenCL.lib` from a vendor SDK. Instead, `build.rs` generates a
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vendor-neutral import library from `windows/OpenCL.def`:
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- **MSVC:** `lib.exe /def:windows\OpenCL.def /out:OpenCL.lib /machine:X64`
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- **GNU:** `dlltool -d windows/OpenCL.def -l libOpenCL.a -m i386:x86-64`
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and puts it on the link search path. The import library only forwards to
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`OpenCL.dll`, which the GPU driver provides at runtime. If the toolchain tool
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isn’t on `PATH`, `build.rs` prints a warning and the link step fails with a clear
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message (compilation/`cargo check` still works).
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## Distribution
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Statically link the MSVC C runtime so users don’t need the VC++ redistributable:
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```powershell
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set RUSTFLAGS=-C target-feature=+crt-static
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cargo build --release
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```
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## Runtime dependencies (on the mining machine)
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- **`OpenCL.dll`** — the ICD loader, installed with any GPU driver (AMD/NVIDIA/
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Intel). Required for the OpenCL backend.
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- **`nvcuda.dll`** + **`nvml.dll`** — installed with the NVIDIA driver. Loaded
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on demand for the CUDA backend; absent on AMD-only machines, where the miner
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simply reports no CUDA devices.
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- The **VC++ runtime**, unless you built with `+crt-static`.
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A `cuda`-enabled binary still starts on a machine with no NVIDIA driver.
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## Building Windows binaries without a Windows machine
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### GitHub Actions (recommended)
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```yaml
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name: windows
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on: [push, workflow_dispatch]
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jobs:
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build:
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runs-on: windows-latest # MSVC + lib.exe already on PATH
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steps:
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- uses: actions/checkout@v4
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- uses: dtolnay/rust-toolchain@stable
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- run: cargo build --release --features gpu,cuda
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env:
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RUSTFLAGS: -C target-feature=+crt-static
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- uses: actions/upload-artifact@v4
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with:
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name: jackpotminer-windows
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path: target/release/*.exe
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```
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### Cross-compile from Linux (GNU target)
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```bash
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rustup target add x86_64-pc-windows-gnu
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sudo pacman -S mingw-w64 # or your distro's mingw-w64 (gives dlltool + linker)
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cargo build --release --target x86_64-pc-windows-gnu --no-default-features --features gpu,cuda
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```
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The MSVC target can’t be linked from Linux. The GUI config tool (`eframe`) is
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easiest to build natively on Windows.
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## Status / caveats
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- **Compilation for Windows is verified** here via `cargo check
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--target x86_64-pc-windows-gnu` (default features, and `gpu,cuda`).
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- The OpenCL **import-library linking** uses the standard `lib.exe`/`dlltool`
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technique; validate it with an actual Windows (or MinGW cross) build, which
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needs those tools present.
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- `relaunch_in_terminal` (reopen-in-a-terminal on GUI launch) is Linux-only;
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harmless on Windows, where double-clicking a console binary already opens a
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console.
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