compiletest: add a proper supports-crate-type: xxx directive (original) (raw)

Apparently needs-dynamic-linking is not equivalent to checking if dylib or cdylib crate types are supported.

• In compiletest, needs-dynamic-linking performs a check based on target cfg's dynamic_linking field + --print=cfg --target $TARGET.
• However, target cfg has an additional field only_cdylib which, if dynamic_linking is true, indicates that only cdylib crate type is supported and not dylib.

  /// Whether dynamic linking is available on this target. Defaults to false.
  pub dynamic_linking: bool,
  /// Whether dynamic linking can export TLS globals. Defaults to true.
  pub dll_tls_export: bool,
  /// If dynamic linking is available, whether only cdylibs are supported.
  pub only_cdylib: bool,

  • This is the case for wasm base, dynamic linking is supported but not dylib crate type, only cdylib is supported.

    // we allow dynamic linking, but only cdylibs. Basically we allow a
    // final library artifact that exports some symbols (a wasm module) but
    // we don't allow intermediate `dylib` crate types
    dynamic_linking: true,
    only_cdylib: true,

Originally posted by @jieyouxu in #130860 (comment)