load("//buck/rules:cc.bzl", "cc_binary")
load("//buck/rules:rust.bzl", "rust_binary")

# wrapgen: writes the Mach-O stub that lets a Darwin program call into a HOST ELF library.
#
# Cider reaches host libraries (fuse, X11, the ffmpeg family) through libelfloader, and the guest
# side of that bridge is a generated stub dylib per host library: elf_wrapper() in
# buck/rules/codegen.bzl runs this tool over the ELF dynamic symbol table at BUILD TIME (it
# dlopen()s the real .so while it runs) and emits a Mach-O whose every export forwards through
# libelfloader. So this is a build-time HOST tool, not something that ships.
#
# THE RUST ONE IS THE BUILD TOOL (#76). The three consumers name //src/linux/libelfloader:wrapgen and
# get this; nothing had to change at those call sites. Gated on generated output rather than on
# behaviour: all 22 libraries the consumers feed it come out byte identical in the .c, the vars
# .h, stdout, stderr and exit code, as do five error paths.
rust_binary(
    name = "wrapgen",
    crate_root = "wrapgen/wrapgen.rs",
    deps = ["//vendor/rust:libc"],
    visibility = ["PUBLIC"],
)

# The C++ original stays beside it as wrapgen_c, the arrangement getuuid_c and elfdep_c already
# have, and for the same reason: scripts/buck-hosttools-parity.nu needs both binaries present to
# compare them, so deleting this would delete the check.
#
# A single translation unit against host headers only (elf.h, link.h, dlfcn.h), linked with the
# C++ driver and -ldl, exactly as the reference does.
# buck-registry: src/libelfloader/wrapgen/wrapgen = wrapgen_c
#
# Same reason as PlistBuddy_c: #76 gave the canonical name to the Rust rewrite, and the artifact
# the REFERENCE build produced comes from wrapgen.cpp, which is this target.
cc_binary(
    name = "wrapgen_c",
    srcs = ["wrapgen/wrapgen.cpp"],
    compiler_flags = [
        "-DDARLING",
        "-Wno-error=implicit-function-declaration",
        "-Wno-nullability-completeness",
        "-Wno-deprecated-declarations",
        "-Wno-availability",
        "-Wno-expansion-to-defined",
        "-Wno-elaborated-enum-base",
        "-Wno-undef-prefix",
    ],
    link_cxx = True,
    linker_flags = ["-ldl"],
    visibility = ["PUBLIC"],
)