Use rake-compiler to compile

.gitignore

@@ -1,8 +1,4 @@
 .ruby-version
 Gemfile.lock
 
-# ignore resources directory, where temp build artifacts are placed
-res
-
-# ignore the gc module build directory
-mod_gc
+tmp

Gemfile

@@ -1,3 +1,4 @@
 source "https://rubygems.org"
 
 gem "rake"
+gem "rake-compiler"

Rakefile

@@ -1,34 +1,36 @@
 # frozen_string_literal: true
 
-$LOAD_PATH << File.expand_path("tool", __dir__)
+require "fileutils"
+require "net/http"
+require "rbconfig"
+require "rake/extensiontask"
 
-require 'fileutils'
-require 'tempfile'
-require 'net/http'
-require 'digest'
-require 'etc'
-require 'mmtk_support'
+task default: [:compile, :install]
 
-task default: %i[compile install]
-
-desc <<~DESC
-  Install the MMTk GC shared object into the Shared GC dir for the currently
-  running Ruby
-DESC
-task :install, :compile do
-  install_mmtk
+Rake::ExtensionTask.new do |ext|
+  ext.name = "librubygc.mmtk"
+  ext.ext_dir = "gc/mmtk"
+  ext.lib_dir = "tmp/binaries"
 end
 
-desc <<~DESC
-  Build the MMTk GC implementation shared object
-DESC
-task :compile do
-  MMTkSupport.new.build
+task :install do
+  FileUtils.mv(Dir.glob("tmp/binaries/*"), RbConfig::CONFIG["modular_gc_dir"])
 end
 
-desc <<~DESC
-  Remove all generated build artifacts
-DESC
-task :clean do
-  system("git clean -ffdx")
+RUBY_HEADERS = %w[
+  ccan/check_type/check_type.h ccan/container_of/container_of.h ccan/list/list.h ccan/str/str.h
+  gc/gc_impl.h gc/gc.h gc/extconf_base.rb
+  darray.h
+]
+task :vendor_ruby_headers do
+  RUBY_HEADERS.each do |file|
+    Net::HTTP.start("raw.githubusercontent.com", 443, use_ssl: true) do |http|
+      resp = http.get("ruby/ruby/refs/heads/master/#{file}")
+
+      FileUtils.mkdir_p(File.dirname(file))
+      open(file, "wb") do |file|
+        file.write(resp.body)
+      end
+    end
+  end
 end

ccan/check_type/check_type.h

@@ -0,0 +1,63 @@
+/* CC0 (Public domain) - see ccan/licenses/CC0 file for details */
+#ifndef CCAN_CHECK_TYPE_H
+#define CCAN_CHECK_TYPE_H
+
+/**
+ * ccan_check_type - issue a warning or build failure if type is not correct.
+ * @expr: the expression whose type we should check (not evaluated).
+ * @type: the exact type we expect the expression to be.
+ *
+ * This macro is usually used within other macros to try to ensure that a macro
+ * argument is of the expected type.  No type promotion of the expression is
+ * done: an unsigned int is not the same as an int!
+ *
+ * ccan_check_type() always evaluates to 0.
+ *
+ * If your compiler does not support typeof, then the best we can do is fail
+ * to compile if the sizes of the types are unequal (a less complete check).
+ *
+ * Example:
+ *	// They should always pass a 64-bit value to _set_some_value!
+ *	#define set_some_value(expr)			\
+ *		_set_some_value((ccan_check_type((expr), uint64_t), (expr)))
+ */
+
+/**
+ * ccan_check_types_match - issue a warning or build failure if types are not same.
+ * @expr1: the first expression (not evaluated).
+ * @expr2: the second expression (not evaluated).
+ *
+ * This macro is usually used within other macros to try to ensure that
+ * arguments are of identical types.  No type promotion of the expressions is
+ * done: an unsigned int is not the same as an int!
+ *
+ * ccan_check_types_match() always evaluates to 0.
+ *
+ * If your compiler does not support typeof, then the best we can do is fail
+ * to compile if the sizes of the types are unequal (a less complete check).
+ *
+ * Example:
+ *	// Do subtraction to get to enclosing type, but make sure that
+ *	// pointer is of correct type for that member.
+ *	#define ccan_container_of(mbr_ptr, encl_type, mbr)			\
+ *		(ccan_check_types_match((mbr_ptr), &((encl_type *)0)->mbr),	\
+ *		 ((encl_type *)						\
+ *		  ((char *)(mbr_ptr) - offsetof(enclosing_type, mbr))))
+ */
+#if defined(HAVE_TYPEOF) && HAVE_TYPEOF
+#define ccan_check_type(expr, type)			\
+	((typeof(expr) *)0 != (type *)0)
+
+#define ccan_check_types_match(expr1, expr2)		\
+	((typeof(expr1) *)0 != (typeof(expr2) *)0)
+#else
+#include "ccan/build_assert/build_assert.h"
+/* Without typeof, we can only test the sizes. */
+#define ccan_check_type(expr, type)					\
+	CCAN_BUILD_ASSERT_OR_ZERO(sizeof(expr) == sizeof(type))
+
+#define ccan_check_types_match(expr1, expr2)				\
+	CCAN_BUILD_ASSERT_OR_ZERO(sizeof(expr1) == sizeof(expr2))
+#endif /* HAVE_TYPEOF */
+
+#endif /* CCAN_CHECK_TYPE_H */

ccan/container_of/container_of.h

@@ -0,0 +1,142 @@
+/* CC0 (Public domain) - see ccan/licenses/CC0 file for details */
+#ifndef CCAN_CONTAINER_OF_H
+#define CCAN_CONTAINER_OF_H
+#include "ccan/check_type/check_type.h"
+
+/**
+ * ccan_container_of - get pointer to enclosing structure
+ * @member_ptr: pointer to the structure member
+ * @containing_type: the type this member is within
+ * @member: the name of this member within the structure.
+ *
+ * Given a pointer to a member of a structure, this macro does pointer
+ * subtraction to return the pointer to the enclosing type.
+ *
+ * Example:
+ *	struct foo {
+ *		int fielda, fieldb;
+ *		// ...
+ *	};
+ *	struct info {
+ *		int some_other_field;
+ *		struct foo my_foo;
+ *	};
+ *
+ *	static struct info *foo_to_info(struct foo *foo)
+ *	{
+ *		return ccan_container_of(foo, struct info, my_foo);
+ *	}
+ */
+#define ccan_container_of(member_ptr, containing_type, member)		\
+	 ((containing_type *)						\
+	  ((char *)(member_ptr)						\
+	   - ccan_container_off(containing_type, member))		\
+	  + ccan_check_types_match(*(member_ptr), ((containing_type *)0)->member))
+
+
+/**
+ * ccan_container_of_or_null - get pointer to enclosing structure, or NULL
+ * @member_ptr: pointer to the structure member
+ * @containing_type: the type this member is within
+ * @member: the name of this member within the structure.
+ *
+ * Given a pointer to a member of a structure, this macro does pointer
+ * subtraction to return the pointer to the enclosing type, unless it
+ * is given NULL, in which case it also returns NULL.
+ *
+ * Example:
+ *	struct foo {
+ *		int fielda, fieldb;
+ *		// ...
+ *	};
+ *	struct info {
+ *		int some_other_field;
+ *		struct foo my_foo;
+ *	};
+ *
+ *	static struct info *foo_to_info_allowing_null(struct foo *foo)
+ *	{
+ *		return ccan_container_of_or_null(foo, struct info, my_foo);
+ *	}
+ */
+static inline char *container_of_or_null_(void *member_ptr, size_t offset)
+{
+	return member_ptr ? (char *)member_ptr - offset : NULL;
+}
+#define ccan_container_of_or_null(member_ptr, containing_type, member)	\
+	((containing_type *)						\
+	 ccan_container_of_or_null_(member_ptr,				\
+			       ccan_container_off(containing_type, member))	\
+	 + ccan_check_types_match(*(member_ptr), ((containing_type *)0)->member))
+
+/**
+ * ccan_container_off - get offset to enclosing structure
+ * @containing_type: the type this member is within
+ * @member: the name of this member within the structure.
+ *
+ * Given a pointer to a member of a structure, this macro does
+ * typechecking and figures out the offset to the enclosing type.
+ *
+ * Example:
+ *	struct foo {
+ *		int fielda, fieldb;
+ *		// ...
+ *	};
+ *	struct info {
+ *		int some_other_field;
+ *		struct foo my_foo;
+ *	};
+ *
+ *	static struct info *foo_to_info(struct foo *foo)
+ *	{
+ *		size_t off = ccan_container_off(struct info, my_foo);
+ *		return (void *)((char *)foo - off);
+ *	}
+ */
+#define ccan_container_off(containing_type, member)	\
+	offsetof(containing_type, member)
+
+/**
+ * ccan_container_of_var - get pointer to enclosing structure using a variable
+ * @member_ptr: pointer to the structure member
+ * @container_var: a pointer of same type as this member's container
+ * @member: the name of this member within the structure.
+ *
+ * Given a pointer to a member of a structure, this macro does pointer
+ * subtraction to return the pointer to the enclosing type.
+ *
+ * Example:
+ *	static struct info *foo_to_i(struct foo *foo)
+ *	{
+ *		struct info *i = ccan_container_of_var(foo, i, my_foo);
+ *		return i;
+ *	}
+ */
+#if defined(HAVE_TYPEOF) && HAVE_TYPEOF
+#define ccan_container_of_var(member_ptr, container_var, member) \
+	ccan_container_of(member_ptr, typeof(*container_var), member)
+#else
+#define ccan_container_of_var(member_ptr, container_var, member)	\
+	((void *)((char *)(member_ptr)	-			\
+		  ccan_container_off_var(container_var, member)))
+#endif
+
+/**
+ * ccan_container_off_var - get offset of a field in enclosing structure
+ * @container_var: a pointer to a container structure
+ * @member: the name of a member within the structure.
+ *
+ * Given (any) pointer to a structure and a its member name, this
+ * macro does pointer subtraction to return offset of member in a
+ * structure memory layout.
+ *
+ */
+#if defined(HAVE_TYPEOF) && HAVE_TYPEOF
+#define ccan_container_off_var(var, member)		\
+	ccan_container_off(typeof(*var), member)
+#else
+#define ccan_container_off_var(var, member)			\
+	((const char *)&(var)->member - (const char *)(var))
+#endif
+
+#endif /* CCAN_CONTAINER_OF_H */