Supported platforms

This page lists the targets Leyline builds for and the tools the BoringSSL build needs.

Supported targets

leyline-bssl-sys compiles BoringSSL from source with the cc crate, from the source lists BoringSSL ships in gen/sources.json, and uses the Rust bindings committed for the target. A build needs no CMake, Go, Perl, or libclang.

On any other target, including Intel macOS (x86_64-apple-darwin), 32-bit targets, and windows-gnu, the build stops with an error that names the supported targets.

The platform a session claims is separate from the build target: a Linux build can claim Windows or macOS. See Choose a platform.

Build BoringSSL

The build compiles the BoringSSL source that ships in leyline-bssl-sys. LEYLINE_BSSL_SOURCE_PATH points the build at another BoringSSL source tree. The build applies Leyline’s patches to that tree in place.

LEYLINE_BSSL_PATH links a BoringSSL that you built yourself. The build applies no patches to it, so it must carry Leyline’s patches and be built with -DBORINGSSL_PREFIX=LEYLINE.

Other variables:

• LEYLINE_BSSL_ASSUME_PATCHED skips the patches for a tree that already carries them. It needs LEYLINE_BSSL_PATH or LEYLINE_BSSL_SOURCE_PATH.
• LEYLINE_BSSL_RUST_CPPLIB replaces the C++ standard library that the build links: by default c++ on macOS, stdc++ on Linux, none on Windows.
• LEYLINE_BSSL_SYSROOT gives bindgen a sysroot when the bindgen feature is on.

The committed bindings match the headers that ship in leyline-bssl-sys. LEYLINE_BSSL_INCLUDE_PATH needs the bindgen feature of leyline-bssl-sys; without it the build stops with an error. When LEYLINE_BSSL_PATH links a BoringSSL whose headers differ, turn on the bindgen feature too.

The build needs:

• A C and C++ compiler: Xcode Command Line Tools on macOS, GCC or Clang on Linux, the MSVC build tools on Windows. The cc crate finds it, and CC, CXX, CFLAGS, and CXXFLAGS work as they do for any cc build.
• Git. Every build runs git apply for Leyline’s patches unless LEYLINE_BSSL_ASSUME_PATCHED is set. A source checkout also uses Git to fetch the BoringSSL submodule.

On Windows, the x86_64 assembly is NASM source. When NASM is on PATH, or NASM names it, the build assembles it. Otherwise it links the objects that ship in prebuilt/x86_64-pc-windows-msvc/, which CI assembles with NASM 2.16.01 from the same source and checks on every run. LEYLINE_BSSL_SOURCE_PATH needs NASM, because the shipped objects match only the bundled BoringSSL.

The build uses the macOS deployment target that Rust uses (MACOSX_DEPLOYMENT_TARGET, 11.0 by default), honors +crt-static on MSVC, and maps the source and output directories to /build, so the libraries embed no local paths. The first build compiles BoringSSL; later builds reuse it.

Windows

Install Visual Studio Build Tools with the C++ workload. A Developer Command Prompt is not required, and NASM is optional.

With the bindgen feature, also install LLVM and set LIBCLANG_PATH to its bin directory, so bindgen finds libclang.dll.

musl

BoringSSL has C++ code, so a musl build needs a musl C and C++ toolchain. The musl-gcc wrapper from musl-tools has no C++ compiler; use a full cross toolchain, such as the musl.cc builds or the one cross ships.

1. Put the toolchain on PATH, for example x86_64-linux-musl-cross/bin.

2. Set the Rust linker to the musl compiler:

   export CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_LINKER=x86_64-linux-musl-gcc
   export CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_LINKER=aarch64-linux-musl-gcc
   

3. Build:

   cargo build -p leyline-http --target x86_64-unknown-linux-musl
   

The build finds <arch>-linux-musl-gcc and <arch>-linux-musl-g++ on PATH; set CC_<target> and CXX_<target> to use another compiler. The musl libstdc++ links statically.

Next

Read the Profile reference for each bundled profile and the capture it comes from.