diff --git a/AGENTS.md b/AGENTS.md index 9108767..091807a 100644 --- a/AGENTS.md +++ b/AGENTS.md @@ -21,7 +21,7 @@ crafter-build is a C++26 modules build system. A project is described by a `proj Partitions and what they own: -- `:Toolchain` resolves the compiler once per process (`GetToolchain`): clang++, clang, llvm-ar, libclang, libc++'s std module source and the default sysroots, from `CRAFTER_BUILD_LLVM_DIR`, else a toolchain installed beside crafter-build, else PATH. It also holds the version baked in at build time. +- `:Toolchain` resolves the compiler once per process (`GetToolchain`): clang++, clang, llvm-ar, libclang, libc++'s std module source and the default sysroots, from `CRAFTER_BUILD_LLVM_DIR`, else a toolchain installed beside crafter-build, else PATH. It also holds the version baked in at build time. `SysrootStdModule` picks the std module source for a sysroot build by the sysroot's libc++ release. - `:Clang` holds `Configuration`, `Build()`, `VariantId()`, `ApplyStandardArgs`, `HostTarget`, the CLI entry point `Crafter::Run`, and the lint and test data types. - `:Platform` runs commands, implements `LoadProject` (compile and load `project.cpp`), the host PCM cache, `#pragma crafter dependency`, and all OS-specific code. - `:Interface` and `:Implementation` model module units, their staleness checks and their compiles. @@ -169,4 +169,5 @@ To release: add a `` to `packaging/flatpak/net.catcrafts.CrafterBuild.m - `crafter-build clean` leaves a pragma dependency's build alone; it lives with the clone in the cache. - The bootstrap binary is compiled without `CRAFTER_BUILD_HAS_ASSET`, so `cfg.assets` only works in the self-hosted binary. Changing asset extensions means updating two maps in `Crafter.Build-Clang.cpp`: `assetOutput` and the transitive copy loop. - A warning is printed only when its unit actually recompiles. A build with nothing to do is silent, which is not evidence that a warning is gone. +- A std module source only compiles against the headers of its own libc++ release, and a sysroot does not always ship one (Alpine). The Flatpak therefore carries the sources of the release next to the bundled one under `share/crafter-build/libc++-modules//`, one `libcxx--modules` manifest module each. When the bundled LLVM is bumped, keep the release it leaves behind as such a module: sysroots on the stable distro stay on it for months. The native loop has no such directory; stage one by hand under `share/crafter-build/` to test against a foreign sysroot. - `VariantId()` names the output directory, so CI globs `bin/crafter.build-exe---*/` rather than predicting the hash. diff --git a/README.md b/README.md index 5296f74..c195fb2 100644 --- a/README.md +++ b/README.md @@ -116,6 +116,8 @@ Inside the Flatpak: /app/bin/clang++ lld llvm-ar wasmtime # the bundled toolchain the executable resolves first /app/lib/libcrafter-build.a # static archive for downstream consumers /app/share/crafter-build/*.cppm # module sources (rebuilt on the user's machine on first run) +/app/share/crafter-build/libc++-modules// + # std module sources of other libc++ releases, for sysroots without their own /app/share/wasi-sysroot/ # WASI sysroot for wasm32 targets ~/.var/app/net.catcrafts.CrafterBuild/cache/crafter.build/---/ # std.pcm + Crafter.Build*.pcm, built locally per toolchain @@ -174,7 +176,7 @@ TestRunner::Cmd("wine") // local exec via prefix co For elaborate setups (rsync, ssh ControlMaster, env vars on the spawn, `QEMU_LD_PREFIX` for sysroots), construct `TestRunner` directly — `copy`/`exec`/`cleanup`/`probe` are public string fields with `{bundle}`, `{remote_bundle}`, `{bin}`, `{bin_name}`, `{args}` placeholders. -For cross-arch builds, set `cfg.sysroot` on the `Configuration` to point at a sysroot for the target. `BuildStdPcm` and the compile/link commands both consume it: `--sysroot=` is passed to clang, and `/usr/share/libc++/v1/std.cppm` is precompiled instead of the host's. The cheapest aarch64 sysroot is an extracted [Arch Linux ARM rootfs](http://os.archlinuxarm.org/) plus `libc++` + `libc++abi` + `gcc` installed into it via `pacman --root --config --dbpath /var/lib/pacman -Sy …` (point pacman at ALARM's mirrors via explicit config to avoid pulling host-arch packages). +For cross-arch builds, set `cfg.sysroot` on the `Configuration` to point at a sysroot for the target. `BuildStdPcm` and the compile/link commands both consume it: `--sysroot=` is passed to clang, and the std module is precompiled against the sysroot's libc++ headers. The module source has to come from the same libc++ release as those headers, so it is taken from `/usr/share/libc++/v1/std.cppm` when the sysroot ships it, else from the toolchain when both are the same major release, else from the sources crafter-build carries for other releases (`share/crafter-build/libc++-modules//`; `crafter-build --version` lists them). Alpine is the common case for the last two: its `libc++-dev` has the headers and no module source. When nothing matches, the build stops with one line naming both releases; installing that release's `share/libc++/v1` directory into the sysroot resolves it. The cheapest aarch64 sysroot is an extracted [Arch Linux ARM rootfs](http://os.archlinuxarm.org/) plus `libc++` + `libc++abi` + `gcc` installed into it via `pacman --root --config --dbpath /var/lib/pacman -Sy …` (point pacman at ALARM's mirrors via explicit config to avoid pulling host-arch packages). For `--target=x86_64-w64-mingw32` (Windows from Linux), the pipeline cross-compiles as long as `mingw-w64` is installed. Pair it with `--runner=cmd:wine` to run the result. Only the MinGW ABI is supported; there is no MSVC target and no Windows host. `-fuse-ld=lld` is auto-injected on every link, and `-lstdc++exp` is auto-linked for the mingw target so user projects don't need to declare those flags.