feat(third_party/bazel): Check in rules_haskell from Tweag

third_party/bazel/rules_haskell/haskell/private/actions/runghc.bzl

@@ -0,0 +1,115 @@
+"""runghc support"""
+
+load(":private/context.bzl", "render_env")
+load(":private/packages.bzl", "expose_packages", "pkg_info_to_compile_flags")
+load(
+    ":private/path_utils.bzl",
+    "get_lib_name",
+    "is_shared_library",
+    "link_libraries",
+    "ln",
+    "target_unique_name",
+)
+load(
+    ":private/set.bzl",
+    "set",
+)
+load(":providers.bzl", "get_libs_for_ghc_linker")
+load("@bazel_skylib//lib:shell.bzl", "shell")
+
+def build_haskell_runghc(
+        hs,
+        runghc_wrapper,
+        user_compile_flags,
+        extra_args,
+        hs_info,
+        output,
+        package_databases,
+        version,
+        lib_info = None):
+    """Build runghc script.
+
+    Args:
+      hs: Haskell context.
+      hs_info: HaskellInfo.
+
+      package_databases: package caches excluding the cache file of the package
+                      we're creating a runghc for.
+      lib_info: If we're building runghc for a library target, pass
+                HaskellLibraryInfo here, otherwise it should be None.
+
+    Returns:
+      None.
+    """
+
+    args = pkg_info_to_compile_flags(expose_packages(
+        hs_info,
+        lib_info,
+        use_direct = False,
+        use_my_pkg_id = None,
+        custom_package_databases = package_databases,
+        version = version,
+    ))
+
+    if lib_info != None:
+        for idir in set.to_list(hs_info.import_dirs):
+            args += ["-i{0}".format(idir)]
+
+    link_ctx = hs_info.cc_dependencies.dynamic_linking
+    libs_to_link = link_ctx.dynamic_libraries_for_runtime.to_list()
+
+    # External C libraries that we need to make available to runghc.
+    link_libraries(libs_to_link, args)
+
+    # Transitive library dependencies to have in runfiles.
+    (library_deps, ld_library_deps, ghc_env) = get_libs_for_ghc_linker(
+        hs,
+        hs_info.transitive_cc_dependencies,
+        path_prefix = "$RULES_HASKELL_EXEC_ROOT",
+    )
+
+    runghc_file = hs.actions.declare_file(target_unique_name(hs, "runghc"))
+
+    # Extra arguments.
+    # `compiler flags` is the default set of arguments for runghc,
+    # augmented by `extra_args`.
+    # The ordering is important, first compiler flags (from toolchain
+    # and local rule), then from `extra_args`. This way the more
+    # specific arguments are listed last, and then have more priority in
+    # GHC.
+    # Note that most flags for GHCI do have their negative value, so a
+    # negative flag in `extra_args` can disable a positive flag set
+    # in `user_compile_flags`, such as `-XNoOverloadedStrings` will disable
+    # `-XOverloadedStrings`.
+    args += hs.toolchain.compiler_flags + user_compile_flags + hs.toolchain.repl_ghci_args
+
+    # ghc args need to be wrapped up in "--ghc-arg=" when passing to runghc
+    runcompile_flags = ["--ghc-arg=%s" % a for a in args]
+    runcompile_flags += extra_args
+
+    hs.actions.expand_template(
+        template = runghc_wrapper,
+        output = runghc_file,
+        substitutions = {
+            "{ENV}": render_env(ghc_env),
+            "{TOOL}": hs.tools.runghc.path,
+            "{ARGS}": " ".join([shell.quote(a) for a in runcompile_flags]),
+        },
+        is_executable = True,
+    )
+
+    # XXX We create a symlink here because we need to force
+    # hs.tools.runghc and the best way to do that is
+    # to use hs.actions.run. That action, in turn must produce
+    # a result, so using ln seems to be the only sane choice.
+    extra_inputs = depset(transitive = [
+        depset([
+            hs.tools.runghc,
+            runghc_file,
+        ]),
+        set.to_depset(package_databases),
+        depset(library_deps),
+        depset(ld_library_deps),
+        set.to_depset(hs_info.source_files),
+    ])
+    ln(hs, runghc_file, output, extra_inputs)