fix: resolve firtool from Chisel metadata

MODULE.bazel

@@ -37,18 +37,10 @@ chisel.toolchain(
 )
 use_repo(
     chisel,
+    "chisel_firtool",
     "chisel_maven",
 )
 
 bazel_dep(name = "rules_python", version = "1.7.0", dev_dependency = True)
 
 bazel_dep(name = "rules_verilog", version = "1.1.1")
-
-circt_repo = use_repo_rule(
-    "//verilog:circt_repo.bzl",
-    "circt_repo",
-)
-
-circt_repo(
-    name = "circt",
-)

README.md

@@ -10,12 +10,16 @@ This repository packages the following helpers as a BCR-friendly module:
 - `chisel_binary`
 - `chisel_library`
 - `chisel_test`
+- `fir_library`
+- `verilog_file`
+- `verilog_directory`
 - `verilog_single_file_library`
 
 ## Features
 
-- One extension (`chisel.toolchain`) to fetch Chisel/ScalaTest Maven artifacts.
+- One extension (`chisel.toolchain`) to fetch Chisel/ScalaTest Maven artifacts and a compatible native firtool.
 - Ready-to-use macro defaults via `@chisel_maven` aliases (`:chisel`, `:chisel_plugin`, etc.).
+- Automatic firtool version selection from Chisel's own build metadata via `@chisel_firtool`.
 - Built-in Verilator runtime wrapper in `chisel_test` for BCR Verilator layout quirks.
 - Minimal smoke tests and GitHub CI workflows.
 
@@ -38,25 +42,25 @@ scala_deps = use_extension("@rules_scala//scala/extensions:deps.bzl", "scala_dep
 scala_deps.scala()
 scala_deps.scalatest()  # only needed if you use chisel_test
 
-# Chisel dependencies (creates @chisel_maven)
+# Chisel dependencies (creates @chisel_maven and @chisel_firtool)
 chisel = use_extension("@rules_chisel//chisel:extensions.bzl", "chisel")
 chisel.toolchain(
     chisel_version = "7.8.0",
     scala_version = "2.13.17", # should match rules_scala's scala_version
     firtool_resolver_version = "2.0.1",  # choose a known compatible resolver for your Chisel release
     lock_file = "//:maven_install.json",  # run `touch maven_install.json && REPIN=1 bazel run @chisel_maven//:pin` to generate the lock file
 )
-use_repo(chisel, "chisel_maven")
+use_repo(chisel, "chisel_firtool", "chisel_maven")
 ```
 
 If you are authoring a reusable Bazel module (not an application root) and only need Chisel for that module's own development/tests, use `dev_dependency = True` on `use_extension(...)` so your toolchain tag does not leak to downstream consumers.
 
-
 ## Notes
 
 - Scala toolchain setup is **mandatory** in your own `MODULE.bazel`. This is by design: `rules_chisel` leaves Scala version/toolchain control to users.
 - `chisel_test` wraps `scala_test` and sets up a Verilator runtime environment. It expects `@verilator//:bin/verilator` and `@verilator//:verilator_includes`. If you don't use `chisel_test`, you can skip the Verilator dependency.
 - Please explicitly set `firtool_resolver_version` in `chisel.toolchain(...)`. Use the Chisel Maven POM as the source of truth (for example: [`chisel_2.13-7.8.0.pom`](https://repo1.maven.org/maven2/org/chipsalliance/chisel_2.13/7.8.0/chisel_2.13-7.8.0.pom), see dependency `firtool-resolver_2.13` with `<version>2.0.1</version>`).
+- `@chisel_firtool` reads the configured Chisel artifact's `BuildInfo.firtoolVersion` and asks `firtool-resolver` for that exact native tool. The download happens while Bazel prepares external repositories, not inside each Verilog action.
 - To make dependency resolution faster, deterministic and avoid repeated conflict-selection drift/noise across builds, set `lock_file` and pin once: `touch maven_install.json && REPIN=1 bazel run @chisel_maven//:pin`.
 - `lock_file` records a resolved result. The first pin still performs dependency resolution; repin when you intentionally change dependency versions.
 
@@ -66,7 +70,13 @@ You can check `tests` for examples as well.
 
 ```starlark
 load("@rules_chisel//chisel:defs.bzl", "chisel_binary", "chisel_library", "chisel_test")
-load("@rules_chisel//verilog:defs.bzl", "verilog_single_file_library")
+load(
+    "@rules_chisel//verilog:defs.bzl",
+    "fir_library",
+    "verilog_directory",
+    "verilog_file",
+    "verilog_single_file_library",
+)
 
 chisel_library(
     name = "adder_lib",
@@ -86,6 +96,21 @@ chisel_test(
     deps = [":adder_lib"],
 )
 
+fir_library(
+    name = "adder_fir",
+    generator = ":emit_adder",
+)
+
+verilog_file(
+    name = "adder.sv",
+    srcs = [":adder_fir"],
+)
+
+verilog_directory(
+    name = "adder_split",
+    srcs = [":adder_fir"],
+)
+
 verilog_single_file_library(
     name = "merged_sv",
     srcs = [
@@ -127,6 +152,7 @@ Local smoke targets:
 bazel build //...
 bazel test //tests/smoke:verilog_concat_test
 bazel test //tests/smoke:simple_adder_test --test_output=errors
+bazel test //tests/smoke:fir_verilog_test --test_output=errors
 tests/version_compat/check_chisel_versions.sh
 ```
 

chisel/extensions.bzl

@@ -4,6 +4,9 @@ load("@rules_jvm_external//:defs.bzl", "maven_install")
 load("@rules_jvm_external//private/extensions:download_pinned_deps.bzl", "download_pinned_deps")
 load("@rules_jvm_external//private/rules:v1_lock_file.bzl", "v1_lock_file")
 load("@rules_jvm_external//private/rules:v2_lock_file.bzl", "v2_lock_file")
+load("//verilog:firtool_repo.bzl", "firtool_repo")
+
+_FIRTOOL_REPO_NAME = "chisel_firtool"
 
 _DEFAULT_REPOSITORIES = [
     "https://repo1.maven.org/maven2",
@@ -170,6 +173,13 @@ def _chisel_extension_impl(module_ctx):
         pin_repo_name = "unpinned_" + internal_repo_name if settings.lock_file else internal_repo_name,
         scala_version = settings.scala_version,
     )
+    firtool_repo(
+        name = _FIRTOOL_REPO_NAME,
+        chisel_version = settings.chisel_version,
+        firtool_resolver_version = settings.firtool_resolver_version,
+        repositories = settings.repositories,
+        scala_version = settings.scala_version,
+    )
 
     root_is_dev = True
     for mod in module_ctx.modules:
@@ -180,8 +190,8 @@ def _chisel_extension_impl(module_ctx):
 
     return module_ctx.extension_metadata(
         reproducible = settings.lock_file != None,
-        root_module_direct_deps = [] if root_is_dev else [settings.repo_name],
-        root_module_direct_dev_deps = [settings.repo_name] if root_is_dev else [],
+        root_module_direct_deps = [] if root_is_dev else [settings.repo_name, _FIRTOOL_REPO_NAME],
+        root_module_direct_dev_deps = [settings.repo_name, _FIRTOOL_REPO_NAME] if root_is_dev else [],
     )
 
 toolchain = tag_class(

tests/version_compat/check_chisel_versions.sh

@@ -83,7 +83,7 @@ chisel.toolchain(
     scala_version = "${SCALA_VERSION}",
     firtool_resolver_version = "${firtool_version}",
 )
-use_repo(chisel, "chisel_maven")
+use_repo(chisel, "chisel_firtool", "chisel_maven")
 MODULE
 
   cat > "${ws}/BUILD.bazel" <<'BUILD'
@@ -100,6 +100,13 @@ chisel_binary(
     deps = [":compat_lib"],
     main_class = "compat.Main",
 )
+
+genrule(
+    name = "firtool_version",
+    outs = ["firtool-version.txt"],
+    cmd = "$(location @chisel_firtool//:bin/firtool) --version > $@",
+    tools = ["@chisel_firtool//:bin/firtool"],
+)
 BUILD
 
   cat > "${ws}/Compat.scala" <<'SCALA'
@@ -135,7 +142,7 @@ SCALA
       --nohome_rc \
       --noworkspace_rc \
       --output_user_root="${out_root}" \
-      build //:compat_lib //:compat_bin \
+      build //:compat_lib //:compat_bin //:firtool_version \
       --enable_bzlmod \
       --repository_cache="${TMP_ROOT}/repo_cache" \
       --disk_cache="${TMP_ROOT}/disk_cache" \

verilog/BUILD.bazel

@@ -3,4 +3,8 @@ package(
     default_visibility = ["//visibility:private"],
 )
 
-exports_files(["defs.bzl"])
+exports_files([
+    "ResolveFirtool.java",
+    "defs.bzl",
+    "firtool_repo.bzl",
+])

verilog/ResolveFirtool.java

@@ -0,0 +1,68 @@
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.InputStream;
+import java.lang.reflect.Method;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+
+public final class ResolveFirtool {
+  private ResolveFirtool() {}
+
+  public static void main(String[] args) throws Exception {
+    if (args.length != 1) {
+      throw new IllegalArgumentException("Usage: ResolveFirtool <output-file>");
+    }
+
+    Object buildInfo = Class.forName("chisel3.BuildInfo$").getField("MODULE$").get(null);
+    Object versionOption = buildInfo.getClass().getMethod("firtoolVersion").invoke(buildInfo);
+    Method isDefined = versionOption.getClass().getMethod("isDefined");
+    if (!(Boolean) isDefined.invoke(versionOption)) {
+      throw new IllegalStateException("The configured Chisel artifact does not declare a firtool version");
+    }
+    String version = (String) versionOption.getClass().getMethod("get").invoke(versionOption);
+
+    String javaExecutable = Paths.get(
+            System.getProperty("java.home"),
+            "bin",
+            System.getProperty("os.name").toLowerCase().startsWith("windows") ? "java.exe" : "java")
+        .toString();
+    ProcessBuilder processBuilder = new ProcessBuilder(
+        javaExecutable,
+        "-cp",
+        System.getProperty("java.class.path"),
+        "firtoolresolver.Main",
+        version);
+    processBuilder.environment().remove("CHISEL_FIRTOOL_PATH");
+    processBuilder.redirectError(ProcessBuilder.Redirect.INHERIT);
+
+    Process process = processBuilder.start();
+    String output;
+    try (InputStream input = process.getInputStream();
+         ByteArrayOutputStream bytes = new ByteArrayOutputStream()) {
+      input.transferTo(bytes);
+      output = bytes.toString(StandardCharsets.UTF_8.name()).trim();
+    }
+    int exitCode = process.waitFor();
+    if (exitCode != 0) {
+      throw new IllegalStateException("firtool-resolver failed with exit code " + exitCode);
+    }
+    if (output.isEmpty()) {
+      throw new IllegalStateException("firtool-resolver did not return a firtool path");
+    }
+
+    String[] outputLines = output.split("\\R");
+    Path source = Paths.get(outputLines[outputLines.length - 1]);
+    Path destination = Paths.get(args[0]);
+    Files.createDirectories(destination.getParent());
+    Files.copy(source, destination, StandardCopyOption.REPLACE_EXISTING);
+    File destinationFile = destination.toFile();
+    if (!destinationFile.setExecutable(true, false) && !destinationFile.canExecute()) {
+      throw new IllegalStateException("Unable to make firtool executable: " + destination);
+    }
+
+    System.out.println("Resolved firtool " + version + " for the configured Chisel artifact");
+  }
+}

verilog/defs.bzl

@@ -47,7 +47,7 @@ fir_library = rule(
             executable = True,
             allow_files = True,
             cfg = "exec",
-            default = Label("@circt//:bin/firtool"),
+            default = Label("@chisel_firtool//:bin/firtool"),
         ),
     },
 )
@@ -112,7 +112,7 @@ def verilog_attrs():
             executable = True,
             allow_files = True,
             cfg = "exec",
-            default = Label("@circt//:bin/firtool"),
+            default = Label("@chisel_firtool//:bin/firtool"),
         ),
     }