Simplify tcl library initialization post switch to Tcl9

In tcl9, we don't need the runfiles anymore as we can use the
embedded zipfs. Remove remants that were needed to provide
runfile support.

Signed-off-by: Henner Zeller <h.zeller@acm.org>

Author: hzeller

bazel/BUILD

@@ -6,7 +6,6 @@ load("@rules_pkg//pkg:mappings.bzl", "pkg_files", "strip_prefix")
 load("@rules_pkg//pkg:zip.bzl", "pkg_zip")
 load("@rules_python//python:pip.bzl", "compile_pip_requirements")
 load("@rules_python//python/entry_points:py_console_script_binary.bzl", "py_console_script_binary")
-load("//bazel:extract_zip.bzl", "extract_zip")
 
 package(features = ["layering_check"])
 
@@ -68,12 +67,6 @@ pkg_zip(
     ],
 )
 
-# ... however, Tcl8 still needs access to a directory, so unpack in that case.
-extract_zip(
-    name = "tcl_resources_dir",
-    src = ":tcl_resources_zip",
-)
-
 genrule(
     name = "tcl_resources_zip_data_h",
     srcs = [":tcl_resources_zip"],
@@ -87,44 +80,15 @@ cc_binary(
     srcs = ["embed.cc"],
 )
 
-# As long as we support tcl8 (using runfiles) we need this flag.
-bool_flag(
-    name = "use_zipfs",
-    build_setting_default = True,  # True as we use tcl9 with zipfs feature
-)
-
-config_setting(
-    name = "zipfs_config",
-    flag_values = {":use_zipfs": "true"},
-)
-
-# Library initialization is a bit different for tcl8 and tcl9.
-# In tcl9, we can use a zipped version of the needed include files, but
-# for tcl8, we have to use the unpacked zip file and point our runfiles
-# to it.
 cc_library(
     name = "tcl_library_init",
-    srcs = ["tcl_library_init.cc"] +
-           select({
-               ":zipfs_config": ["tcl_resources_zip_data.h"],
-               "//conditions:default": [],
-           }),
+    srcs = [
+        "tcl_library_init.cc",
+        "tcl_resources_zip_data.h",
+    ],
     hdrs = ["tcl_library_init.h"],
-    copts = select({
-        ":zipfs_config": [],
-        "//conditions:default": ["-DUSE_TCL_RUNFILE_INIT"],
-    }),
-    data = select({
-        ":zipfs_config": [],
-        "//conditions:default": [":tcl_resources_dir"],
-    }),
     visibility = ["//visibility:public"],
-    deps = [
-        "@tcl_lang//:tcl",
-    ] + select({
-        ":zipfs_config": [],
-        "//conditions:default": ["@rules_cc//cc/runfiles"],
-    }),
+    deps = ["@tcl_lang//:tcl"],
 )
 
 # small build test to check if "bazel build //src/sta:StaTclInitVar" works

bazel/extract_zip.bzl

@@ -3,130 +3,26 @@
 
 #include "bazel/tcl_library_init.h"
 
-#include <cstdlib>
-#include <filesystem>
 #include <iostream>
 #include <optional>
 #include <string>
-#include <system_error>
 
-#include "tcl.h"
-
-// In tcl 9, we can use the //zipfs:/ virtual file system (unless
-// we specifically disabled with the --//bazel:use_zipfs=False flag)
-#if TCL_MAJOR_VERSION >= 9 && !defined(USE_TCL_RUNFILE_INIT)
-#define USE_ZIPFS_INIT 1
-#else
-#define USE_ZIPFS_INIT 0
-#endif
-
-#if USE_ZIPFS_INIT
 #include "bazel/tcl_resources_zip_data.h"
-#else
-
-#include <limits.h>
-#include <unistd.h>
-
-#if defined(__APPLE__)
-#include <mach-o/dyld.h>
-#include <sys/param.h>
-#endif
-
-#include <memory>
-
-#include "rules_cc/cc/runfiles/runfiles.h"
-#endif
+#include "tcl.h"
 
 namespace in_bazel {
 
-#if !USE_ZIPFS_INIT
-// Avoid adding any dependencies like boost.filesystem
-// Returns path to running binary if possible.
-static std::string GetProgramLocation()
-{
-#if defined(_WIN32)
-  char result[MAX_PATH + 1] = {'\0'};
-  auto path_len = GetModuleFileNameA(NULL, result, MAX_PATH);
-#elif defined(__APPLE__)
-  char result[MAXPATHLEN + 1] = {'\0'};
-  uint32_t path_len = MAXPATHLEN;
-  if (_NSGetExecutablePath(result, &path_len) != 0) {
-    path_len = readlink(result, result, MAXPATHLEN);
-  }
-#else
-  char result[PATH_MAX + 1] = {'\0'};
-  ssize_t path_len = readlink("/proc/self/exe", result, PATH_MAX);
-#endif
-  if (path_len > 0) {
-    return result;
-  }
-  return Tcl_GetNameOfExecutable();
-}
-#endif
-
 static std::optional<std::string> TclLibraryMountPoint(Tcl_Interp* interp)
 {
   // In tcl9, we can use //zipfs:/ otherwise we need to point to the
   // directory where the tcl library files are extracted.
-#if USE_ZIPFS_INIT
   if (TclZipfs_MountBuffer(
           interp, kTclResourceZip, sizeof(kTclResourceZip), "/app", 0)
       != TCL_OK) {
     std::cerr << "[Warning] Failed to mount Tcl zipfs.\n";
     return std::nullopt;
   }
   return Tcl_GetStringResult(interp);
-#else
-  using rules_cc::cc::runfiles::Runfiles;
-
-  auto find_tcl_resources
-      = [](const Runfiles* runfiles) -> std::optional<std::string> {
-    std::error_code ec;
-    for (const std::string loc : {"openroad", "opensta", "_main"}) {
-      const std::string check_loc = loc + "/bazel/tcl_resources_dir";
-      const std::string path = runfiles->Rlocation(check_loc);
-      if (!path.empty() && std::filesystem::exists(path, ec)) {
-        return path;
-      }
-    }
-    return std::nullopt;
-  };
-
-  // First try with the inherited RUNFILES_* env vars.  When OpenROAD
-  // is the direct Bazel target (or invoked from an sh_test whose
-  // runfiles tree also contains OpenROAD's data), those env vars
-  // already point at the correct tree.
-  std::string error;
-  std::unique_ptr<Runfiles> runfiles(
-      Runfiles::Create(GetProgramLocation(), BAZEL_CURRENT_REPOSITORY, &error));
-  if (runfiles) {
-    if (auto path = find_tcl_resources(runfiles.get())) {
-      return path;
-    }
-  }
-
-  // Fallback: when OpenROAD is invoked by a build system that
-  // previously ran another Bazel binary (e.g. a Python wrapper), the
-  // inherited RUNFILES_* variables point to the *other* binary's
-  // runfiles tree and won't contain OpenROAD's tcl_resources_dir.
-  // Unset them and retry so Runfiles::Create falls back to the
-  // exe_path derived from /proc/self/exe.
-  unsetenv("RUNFILES_DIR");
-  unsetenv("RUNFILES_MANIFEST_FILE");
-  unsetenv("RUNFILES_MANIFEST_ONLY");
-
-  runfiles.reset(
-      Runfiles::Create(GetProgramLocation(), BAZEL_CURRENT_REPOSITORY, &error));
-  if (!runfiles) {
-    std::cerr << "[Warning] Failed to create bazel runfiles: " << error << "\n";
-    return std::nullopt;
-  }
-
-  if (auto path = find_tcl_resources(runfiles.get())) {
-    return path;
-  }
-  return std::nullopt;
-#endif
 }
 
 int SetupTclEnvironment(Tcl_Interp* interp)