Make MMTk a runtime option (#14)

This commit makes MMTk a runtime option.

Code related to MMTk is still by a macro (USE_MMTK, previously USE_THIRD_PARTY_HEAP), but MMTk also needs to be enabled at run time using command line options (`--mmtk` or `--enable-mmtk`), or environment variables (`RUBYOPT=--mmtk` or `MMTK_PLAN=...`)

Author: chrisseaton

gc.c

@@ -118,13 +118,14 @@ VALUE rb_gc_disable_no_rest(void);
 
 struct rb_thread_struct;
 
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
 #define MMTK_DEFAULT_PLAN "MarkSweep"
-void rb_gc_init_collection();
+void rb_gc_init_collection(void);
 void rb_mmtk_pre_process_opts(int argc, char **argv);
 void rb_mmtk_post_process_opts(const char *arg);
-void rb_mmtk_post_process_opts_finish(bool enable);
-#endif // USE_THIRD_PARTY_HEAP
+void rb_mmtk_post_process_opts_finish(bool feature_enable);
+bool rb_mmtk_enabled_p(void);
+#endif
 
 RUBY_SYMBOL_EXPORT_BEGIN
 

gc.h

@@ -30,15 +30,15 @@
 # undef RUBY_DEBUG_ENV
 #endif
 
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
 #include "gc.h"
 #endif
 
 static int
 rb_main(int argc, char **argv)
 {
     RUBY_INIT_STACK;
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
     rb_mmtk_pre_process_opts(argc, argv);
 #endif
     ruby_init();

main.c

@@ -40,6 +40,10 @@
 #include "ruby/assert.h"
 #include "builtin.h"
 
+#if USE_MMTK
+#include "gc.h"
+#endif
+
 /*!
  * \addtogroup object
  * \{
@@ -284,7 +288,13 @@ init_copy(VALUE dest, VALUE obj)
     }
     RBASIC(dest)->flags &= ~(T_MASK|FL_EXIVAR);
     RBASIC(dest)->flags |= RBASIC(obj)->flags & (T_MASK|FL_EXIVAR);
-    rb_copy_wb_protected_attribute(dest, obj);
+#if USE_MMTK
+    if (!rb_mmtk_enabled_p()) {
+#endif
+        rb_copy_wb_protected_attribute(dest, obj);
+#if USE_MMTK
+    }
+#endif
     rb_copy_generic_ivar(dest, obj);
     rb_gc_copy_finalizer(dest, obj);
     if (RB_TYPE_P(obj, T_OBJECT)) {

object.c

@@ -61,7 +61,7 @@
 #include "ruby/version.h"
 #include "ruby/internal/error.h"
 
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
 #include "gc.h"
 #endif
 
@@ -291,7 +291,7 @@ usage(const char *name, int help, int highlight, int columns)
 #if YJIT_BUILD
         M("--yjit",        "",                     "enable in-process JIT compiler (experimental)"),
 #endif
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
         M("--mmtk",        "",                     "use MMTk for garbage collection (experimental)"),
 #endif
         M("-h",		   "",			   "show this message, --help for more info"),
@@ -328,7 +328,7 @@ usage(const char *name, int help, int highlight, int columns)
 #if YJIT_BUILD
         M("yjit", "",           "in-process JIT compiler (default: disabled)"),
 #endif
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
         M("mmtk", "",           "MMTk garbage collection (default: disabled)"),
 #endif
     };
@@ -350,7 +350,7 @@ usage(const char *name, int help, int highlight, int columns)
         M("--yjit-greedy-versioning",  "", "Greedy versioning mode (default: disabled)"),
     };
 #endif
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
     static const struct ruby_opt_message mmtk_options[] = {
         M("--mmtk-plan=name",          "", "MMTk garbage collection plan to use (default: " MMTK_DEFAULT_PLAN ")"),
     };
@@ -391,7 +391,7 @@ usage(const char *name, int help, int highlight, int columns)
     for (i = 0; i < numberof(yjit_options); ++i)
         SHOW(yjit_options[i]);
 #endif
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
     printf("%s""MMTk options (experimental):%s\n", sb, se);
     for (i = 0; i < numberof(mmtk_options); ++i)
         SHOW(mmtk_options[i]);
@@ -1468,7 +1468,7 @@ proc_options(long argc, char **argv, ruby_cmdline_options_t *opt, int envopt)
 #endif
             }
             else if (is_option_with_optarg("mmtk", '-', true, false, false)) {
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
                 FEATURE_SET(opt->features, FEATURE_BIT(mmtk));
                 rb_mmtk_post_process_opts(s);
 #undef opt_match_noarg
@@ -1841,7 +1841,7 @@ process_options(int argc, char **argv, ruby_cmdline_options_t *opt)
         FEATURE_SET_RESTORE(opt->warn, warn);
     }
 
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
     rb_mmtk_post_process_opts_finish(FEATURE_SET_P(opt->features, mmtk));
 #endif
 

ruby.c

@@ -46,9 +46,9 @@
 #include "ruby_assert.h"
 #include "vm_sync.h"
 
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
 #include "mmtk.h"
-#endif // USE_THIRD_PARTY_HEAP
+#endif
 
 #if defined HAVE_CRYPT_R
 # if defined HAVE_CRYPT_H
@@ -475,9 +475,11 @@ fstr_update_callback(st_data_t *key, st_data_t *value, st_data_t data, int exist
         }
         RBASIC(str)->flags |= RSTRING_FSTR;
 
-#ifdef USE_THIRD_PARTY_HEAP
-        mmtk_register_finalizable((void *)str);
-#endif // USE_THIRD_PARTY_HEAP
+#if USE_MMTK
+        if (rb_mmtk_enabled_p()) {
+            mmtk_register_finalizable((void *)str);
+        }
+#endif
 
         *key = *value = arg->fstr = str;
         return ST_CONTINUE;

string.c

@@ -56,7 +56,7 @@ def eval_with_jit_without_retry(env = nil, script, verbose: 0, min_calls: 5, sav
   end
 
   def supported?
-    return false if defined?(GC::MMTk)
+    return false if defined?(GC::MMTk) && GC::MMTk.enabled?
     return @supported if defined?(@supported)
     @supported = RbConfig::CONFIG["MJIT_SUPPORT"] != 'no' && UNSUPPORTED_COMPILERS.all? do |regexp|
       !regexp.match?(RbConfig::CONFIG['MJIT_CC'])

test/lib/jit_support.rb

@@ -100,9 +100,9 @@
 #include "vm_debug.h"
 #include "vm_sync.h"
 
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
 #include "mmtk.h"
-#endif // USE_THIRD_PARTY_HEAP
+#endif
 
 #ifndef USE_NATIVE_THREAD_PRIORITY
 #define USE_NATIVE_THREAD_PRIORITY 0
@@ -650,12 +650,12 @@ thread_start_func_2(rb_thread_t *th, VALUE *stack_start)
     VM_ASSERT(th != th->vm->ractor.main_thread);
     RUBY_DEBUG_LOG("th:%u", rb_th_serial(th));
 
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
     // Threads may be reused, so we only initialize MMTk mutator once.
-    if (th->mutator == NULL) {
+    if (rb_mmtk_enabled_p() && th->mutator == NULL) {
         th->mutator = mmtk_bind_mutator((MMTk_VMMutatorThread)th);
     }
-#endif // USE_THIRD_PARTY_HEAP
+#endif
 
     // setup native thread
     thread_sched_to_running(TH_SCHED(th), th);

thread.c

@@ -66,7 +66,7 @@ AS_IF([test -n "$with_mmtk_ruby"], [
         AC_MSG_ERROR([$MMTK_RUBY_SO_NAME does not exist. $mmtk_ruby_build_suggestion])
     ])
 
-    AC_DEFINE([USE_THIRD_PARTY_HEAP])
+    AC_DEFINE([USE_MMTK], [1])
     AC_DEFINE([USE_TRANSIENT_HEAP], [0])
 
     mmtk_ruby_so_realpath=$(realpath $mmtk_ruby_so_path)
@@ -78,6 +78,7 @@ AS_IF([test -n "$with_mmtk_ruby"], [
     AC_SUBST([mmtk_ruby_lib_dir])
 ], [
     AC_MSG_RESULT([no])
+    AC_DEFINE([USE_MMTK], [0])
     gc_support="Ruby's built-in GC"
 ])
 

tool/m4/mmtk_ruby.m4

@@ -16,7 +16,8 @@
 #include "yjit.h"
 #include <stdio.h>
 
-#ifdef USE_THIRD_PARTY_HEAP
+#if USE_MMTK
+#include "gc.h"
 #include "mmtk.h"
 #endif
 
@@ -115,10 +116,10 @@ Init_ruby_description(void)
             ruby_description_pre,
             MJIT_OPTS_ON ? " +MJIT" : "",
             rb_yjit_enabled_p() ? " +YJIT" : "",
-#ifdef USE_THIRD_PARTY_HEAP
-            " +MMTk(",
-            mmtk_plan_name(),
-            ")",
+#if USE_MMTK
+            rb_mmtk_enabled_p() ? " +MMTk(" : "",
+            rb_mmtk_enabled_p() ? mmtk_plan_name() : "",
+            rb_mmtk_enabled_p() ? ")" : "",
 #else
             "", "", "",
 #endif