Add --mmtk option, but at the moment it has to match the compilation configuration

Author: chrisseaton

gc.c

@@ -158,6 +158,7 @@ RubyUpcalls ruby_upcalls;
 #endif
 
 #ifdef USE_THIRD_PARTY_HEAP
+static bool mmtk_enable = false;
 static const char *mmtk_env_plan = NULL;
 static const char *mmtk_pre_arg_plan = NULL;
 static const char *mmtk_post_arg_plan = NULL;
@@ -15143,6 +15144,9 @@ void rb_mmtk_pre_process_opts(int argc, char **argv) {
     bool enable_rubyopt = true;
 
     mmtk_env_plan = getenv("MMTK_PLAN");
+    if (mmtk_env_plan) {
+        mmtk_enable = true;
+    }
 
     for (int n = 1; n < argc; n++) {
         if (strcmp(argv[n], "--") == 0) {
@@ -15222,10 +15226,14 @@ void rb_mmtk_post_process_opts(const char *s) {
     }
 }
 
-void rb_mmtk_post_process_opts_finish(void) {
+void rb_mmtk_post_process_opts_finish(bool enable) {
+    mmtk_enable |= enable;
     if (strcmp(mmtk_pre_arg_plan ? mmtk_pre_arg_plan : "", mmtk_post_arg_plan ? mmtk_post_arg_plan : "") != 0) {
         rb_raise(rb_eRuntimeError, "--mmtk-plan values disagree");
     }
+    if (!mmtk_enable) {
+        rb_bug("must enable MMTk");
+    }
 }
 
 #endif

gc.h

@@ -123,7 +123,7 @@ struct rb_thread_struct;
 void rb_gc_init_collection();
 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(void);
+void rb_mmtk_post_process_opts_finish(bool enable);
 #endif // USE_THIRD_PARTY_HEAP
 
 RUBY_SYMBOL_EXPORT_BEGIN

ruby.c

@@ -105,6 +105,8 @@ void rb_warning_category_update(unsigned int mask, unsigned int bits);
     X(mjit) \
     SEP \
     X(yjit) \
+    SEP \
+    X(mmtk) \
     /* END OF FEATURES */
 #define EACH_DEBUG_FEATURES(X, SEP) \
     X(frozen_string_literal) \
@@ -194,6 +196,7 @@ enum {
 #endif
 	& ~FEATURE_BIT(frozen_string_literal)
         & ~feature_jit_mask
+        & ~FEATURE_BIT(mmtk)
 	)
 };
 
@@ -211,6 +214,9 @@ cmdline_options_init(ruby_cmdline_options_t *opt)
 #elif defined(YJIT_FORCE_ENABLE)
     opt->features.set |= FEATURE_BIT(yjit);
 #endif
+#ifdef MMTK_FORCE_ENABLE /* to use with: ./configure cppflags="-DMMTK_FORCE_ENABLE" */
+    opt->features.set |= FEATURE_BIT(mmtk);
+#endif
 
     return opt;
 }
@@ -284,6 +290,9 @@ usage(const char *name, int help, int highlight, int columns)
 #endif
 #if YJIT_BUILD
         M("--yjit",        "",                     "enable in-process JIT compiler (experimental)"),
+#endif
+#ifdef USE_THIRD_PARTY_HEAP
+        M("--mmtk",        "",                     "use MMTk for garbage collection (experimental)"),
 #endif
 	M("-h",		   "",			   "show this message, --help for more info"),
     };
@@ -318,6 +327,9 @@ usage(const char *name, int help, int highlight, int columns)
 #endif
 #if YJIT_BUILD
         M("yjit", "",           "in-process JIT compiler (default: disabled)"),
+#endif
+#ifdef USE_THIRD_PARTY_HEAP
+        M("mmtk", "",           "MMTk garbage collection (default: disabled)"),
 #endif
     };
     static const struct ruby_opt_message warn_categories[] = {
@@ -1457,6 +1469,7 @@ proc_options(long argc, char **argv, ruby_cmdline_options_t *opt, int envopt)
             }
             else if (is_option_with_optarg("mmtk", '-', true, false, false)) {
 #ifdef USE_THIRD_PARTY_HEAP
+                FEATURE_SET(opt->features, FEATURE_BIT(mmtk));
                 rb_mmtk_post_process_opts(s);
 #undef opt_match_noarg
 #undef opt_match_arg
@@ -1829,7 +1842,7 @@ process_options(int argc, char **argv, ruby_cmdline_options_t *opt)
     }
 
 #ifdef USE_THIRD_PARTY_HEAP
-    rb_mmtk_post_process_opts_finish();
+    rb_mmtk_post_process_opts_finish(FEATURE_SET_P(opt->features, mmtk));
 #endif
 
     if (opt->src.enc.name)