Add --without-stdlib option to exclude stdlib components

Author: kateinoigakukun

lib/ruby_wasm/cli.rb

@@ -53,6 +53,7 @@ def build(args)
         target_triplet: "wasm32-unknown-wasip1",
         profile: "full",
         stdlib: true,
+        without_stdlib_components: [],
         dest_dir: nil,
         disable_gems: false,
         gemfile: nil,
@@ -105,6 +106,10 @@ def build(args)
             options[:stdlib] = stdlib
           end
 
+          opts.on("--without-stdlib COMPONENT", "Exclude stdlib component") do |component|
+            options[:without_stdlib_components] << component
+          end
+
           opts.on("--disable-gems", "Disable gems") do
             options[:disable_gems] = true
           end

lib/ruby_wasm/packager.rb

@@ -36,7 +36,13 @@ def package(executor, dest_dir, options)
 
     fs.package_gems
     fs.remove_non_runtime_files(executor)
-    fs.remove_stdlib(executor) unless options[:stdlib]
+    if options[:stdlib]
+      options[:without_stdlib_components].each do |component|
+        fs.remove_stdlib_component(executor, component)
+      end
+    else
+      fs.remove_stdlib(executor)
+    end
 
     if full_build_options[:target] == "wasm32-unknown-wasip1" && !features.support_dynamic_linking?
       # wasi-vfs supports only WASI target
@@ -46,7 +52,7 @@ def package(executor, dest_dir, options)
 
       wasm_bytes = wasi_vfs.pack(wasm_bytes)
     end
-    wasm_bytes = ruby_core.link_gem_exts(executor, fs.bundle_dir, wasm_bytes)
+    wasm_bytes = ruby_core.link_gem_exts(executor, fs.ruby_root, fs.bundle_dir, wasm_bytes)
 
     wasm_bytes = RubyWasmExt.preinitialize(wasm_bytes) if options[:optimize]
     wasm_bytes

lib/ruby_wasm/packager/core.rb

@@ -41,7 +41,7 @@ def build_gem_exts(executor, gem_home)
       raise NotImplementedError
     end
 
-    def link_gem_exts(executor, gem_home, module_bytes)
+    def link_gem_exts(executor, ruby_root, gem_home, module_bytes)
       raise NotImplementedError
     end
 
@@ -110,15 +110,13 @@ def build_gem_exts(executor, gem_home)
       self._build_gem_exts(executor, build, gem_home)
     end
 
-    def link_gem_exts(executor, gem_home, module_bytes)
+    def link_gem_exts(executor, ruby_root, gem_home, module_bytes)
       build = derive_build
-      self._link_gem_exts(executor, build, gem_home)
+      self._link_gem_exts(executor, build, ruby_root, gem_home, module_bytes)
     end
 
-    def _link_gem_exts(executor, build, gem_home)
-      ruby_root = build.crossruby.dest_dir
-
-      libraries = [File.join(ruby_root, "usr", "local", "bin", "ruby")]
+    def _link_gem_exts(executor, build, ruby_root, gem_home, module_bytes)
+      libraries = []
 
       # TODO: Should be computed from dyinfo of ruby binary
       wasi_libc_shared_libs = [
@@ -138,14 +136,16 @@ def _link_gem_exts(executor, build, gem_home)
       wasi_adapter = RubyWasm::Packager::ComponentAdapter.wasi_snapshot_preview1(wasi_exec_model)
       adapters = [wasi_adapter]
       dl_openable_libs = []
-      dl_openable_libs << [File.join(ruby_root, "usr"), Dir.glob(File.join(ruby_root, "usr", "local", "lib", "ruby", "**", "*.so"))]
+      dl_openable_libs << [File.dirname(ruby_root), Dir.glob(File.join(ruby_root, "lib", "ruby", "**", "*.so"))]
       dl_openable_libs << [gem_home, Dir.glob(File.join(gem_home, "**", "*.so"))]
 
       linker = RubyWasmExt::ComponentLink.new
       linker.use_built_in_libdl(true)
       linker.stub_missing_functions(false)
       linker.validate(ENV["RUBYWASM_SKIP_LINKER_VALIDATION"] != "1")
 
+      linker.library("ruby", module_bytes, false)
+
       libraries.each do |lib|
         # Non-DL openable libraries should be referenced as base name
         lib_name = File.basename(lib)
@@ -333,7 +333,7 @@ def build_gem_exts(executor, gem_home)
       # No-op because we already built extensions as part of the Ruby build
     end
 
-    def link_gem_exts(executor, gem_home, module_bytes)
+    def link_gem_exts(executor, ruby_root, gem_home, module_bytes)
       return module_bytes unless @packager.features.support_component_model?
 
       linker = RubyWasmExt::ComponentEncode.new

lib/ruby_wasm/packager/file_system.rb

@@ -38,6 +38,23 @@ def remove_stdlib(executor)
     File.write(rbconfig, rbconfig_contents)
   end
 
+  def remove_stdlib_component(executor, component)
+    RubyWasm.logger.info "Removing stdlib component: #{component}"
+    case component
+    when "enc"
+      # Remove all encodings except for encdb.so and transdb.so
+      enc_dir = File.join(@ruby_root, "lib", "ruby", ruby_version, "wasm32-wasi", "enc")
+      puts File.join(enc_dir, "**/*.so")
+      Dir.glob(File.join(enc_dir, "**/*.so")).each do |entry|
+        next if entry.end_with?("encdb.so", "transdb.so")
+        RubyWasm.logger.debug "Removing stdlib encoding: #{entry}"
+        executor.rm_rf entry
+      end
+    else
+      raise "Unknown stdlib component: #{component}"
+    end
+  end
+
   def package_gems
     @packager.specs.each do |spec|
       RubyWasm.logger.info "Packaging gem: #{spec.full_name}"