extension: add yosys_plugins attribute to orfs.default()

config.bzl

@@ -6,6 +6,9 @@ def _global_config_impl(repository_ctx):
         num_cpus = int(result.stdout.strip())
     else:
         num_cpus = 4
+    yosys_plugins_repr = "[" + ", ".join(
+        ['"{}"'.format(p) for p in repository_ctx.attr.yosys_plugins],
+    ) + "]"
     repository_ctx.file(
         "global_config.bzl",
         """
@@ -19,6 +22,7 @@ CONFIG_PDK = "{pdk}"
 CONFIG_YOSYS = "{yosys}"
 CONFIG_YOSYS_ABC = "{yosys_abc}"
 CONFIG_YOSYS_SHARE = "{yosys_share}"
+CONFIG_YOSYS_PLUGINS = {yosys_plugins}
 NUM_CPUS = {num_cpus}
 """.format(
             klayout = repository_ctx.attr.klayout,
@@ -31,6 +35,7 @@ NUM_CPUS = {num_cpus}
             yosys = repository_ctx.attr.yosys,
             yosys_abc = repository_ctx.attr.yosys_abc,
             yosys_share = repository_ctx.attr.yosys_share,
+            yosys_plugins = yosys_plugins_repr,
             num_cpus = num_cpus,
         ),
     )
@@ -68,6 +73,7 @@ global_config = repository_rule(
             cfg = "exec",
         ),
         "yosys_share": attr.label(mandatory = True),
+        "yosys_plugins": attr.label_list(),
     },
     doc = "A repository that provides global configuration values as strings.",
 )

extension.bzl

@@ -66,6 +66,12 @@ _default_tag = tag_class(
             mandatory = False,
             default = Label("@yosys//:yosys_share"),
         ),
+        "yosys_plugins": attr.label_list(
+            mandatory = False,
+            doc = "Extra .so plugin files to expose via YOSYS_PLUGIN_PATH " +
+                  "during yosys actions. Use to load out-of-tree plugins " +
+                  "(e.g. yosys-slang) without merging them into yosys_share.",
+        ),
     },
 )
 
@@ -90,6 +96,7 @@ def _orfs_repositories_impl(module_ctx):
             yosys = default.yosys,
             yosys_abc = default.yosys_abc,
             yosys_share = default.yosys_share,
+            yosys_plugins = default.yosys_plugins,
         )
 
         load_json_file(

private/attrs.bzl

@@ -12,6 +12,7 @@ load(
     "CONFIG_PDK",
     "CONFIG_YOSYS",
     "CONFIG_YOSYS_ABC",
+    "CONFIG_YOSYS_PLUGINS",
     "CONFIG_YOSYS_SHARE",
 )
 load(
@@ -163,6 +164,12 @@ def yosys_only_attrs():
             cfg = "exec",
             default = CONFIG_YOSYS_SHARE,
         ),
+        "_yosys_plugins": attr.label_list(
+            doc = "Extra .so plugin files exposed via YOSYS_PLUGIN_PATH.",
+            allow_files = True,
+            cfg = "exec",
+            default = CONFIG_YOSYS_PLUGINS,
+        ),
     }
 
 def renamed_inputs_attr():

private/environment.bzl

@@ -55,11 +55,19 @@ def yosys_environment(ctx):
         "YOSYS_EXE": ctx.executable.yosys.path,
     } | orfs_environment(ctx)
 
-    # When yosys_share is a single tree artifact (e.g. merged share with
-    # plugins), tell yosys where to find plugins via YOSYS_PLUGIN_PATH.
-    # BCR yosys discovers plugins via /proc/self/exe and won't find plugins
-    # that live outside its own share/ tree without this hint.
-    if len(ctx.files._yosys_share) == 1:
+    # Tell yosys where to find out-of-tree plugins (e.g. yosys-slang)
+    # via YOSYS_PLUGIN_PATH. BCR yosys discovers plugins via
+    # /proc/self/exe and won't find plugins that live outside its own
+    # share/ tree without this hint.
+    plugin_dirs = []
+    for f in ctx.files._yosys_plugins:
+        if f.dirname not in plugin_dirs:
+            plugin_dirs.append(f.dirname)
+    if plugin_dirs:
+        env["YOSYS_PLUGIN_PATH"] = ":".join(plugin_dirs)
+    elif len(ctx.files._yosys_share) == 1:
+        # Backwards-compat: a single tree-artifact yosys_share with a
+        # plugins/ subdir still works.
         env["YOSYS_PLUGIN_PATH"] = ctx.files._yosys_share[0].path + "/plugins"
     return env
 
@@ -133,7 +141,7 @@ def test_inputs(ctx):
 
 def yosys_inputs(ctx):
     return depset(
-        ctx.files._yosys_share,
+        ctx.files._yosys_share + ctx.files._yosys_plugins,
         transitive = [
             _runfiles(
                 [