Rename --jit to --mjit (#5248)

* Rename --jit to --mjit

[Feature #18349]

* Fix a few more --jit references

* Fix MJIT Actions

* More s/jit/mjit/ and re-introduce --disable-jit

* Update NEWS.md

* Fix test_bug_reporter_add

.github/workflows/mjit.yml

@@ -20,12 +20,12 @@ jobs:
     strategy:
       matrix:
         test_task: [ "check" ] # to make job names consistent
-        jit_opts: [ "--jit", "--jit-wait" ]
+        jit_opts: [ "--mjit", "--mjit-wait" ]
       fail-fast: false
     runs-on: ubuntu-latest
     env:
       TESTOPTS: '-q --tty=no'
-      RUN_OPTS: '--disable-gems ${{ matrix.jit_opts }} --jit-debug=-ggdb3'
+      RUN_OPTS: '--disable-gems ${{ matrix.jit_opts }} --mjit-debug=-ggdb3'
       GITPULLOPTIONS: --no-tags origin ${{github.ref}}
     steps:
       - run: mkdir build

NEWS.md

@@ -419,9 +419,14 @@ Excluding feature bug fixes.
   This feature is turned off by default and can be enabled by compiling Ruby
   with flag `USE_RVARGC=1` set. [[Feature #18045]] [[Feature #18239]]
 
-### JIT
+## JIT
 
-* The default `--jit-max-cache` is changed from 100 to 10000.
+* Rename Ruby 3.0's `--jit` to `--mjit`, and alias `--jit` to `--yjit`
+  on non-Windows x86-64 platforms and to `--mjit` on others.
+
+### MJIT
+
+* The default `--mjit-max-cache` is changed from 100 to 10000.
 
 * JIT-ed code is no longer cancelled when a TracePoint for class events
   is enabled.
@@ -429,7 +434,7 @@ Excluding feature bug fixes.
 * The JIT compiler no longer skips compilation of methods longer than
   1000 instructions.
 
-* `--jit-verbose` and `--jit-warning` output "JIT cancel" when JIT-ed
+* `--mjit-verbose` and `--mjit-warning` output "JIT cancel" when JIT-ed
   code is disabled because TracePoint or GC.compact is used.
 
 * `RubyVM::MJIT` is renamed to `RubyVM::JIT`. [[Feature #17490]]

mjit_worker.c

@@ -249,7 +249,7 @@ static char *tmp_dir;
 static const char *cc_path;
 // Used C compiler flags.
 static const char **cc_common_args;
-// Used C compiler flags added by --jit-debug=...
+// Used C compiler flags added by --mjit-debug=...
 static char **cc_added_args;
 // Name of the precompiled header file.
 static char *pch_file;
@@ -686,7 +686,7 @@ remove_so_file(const char *so_file, struct rb_mjit_unit *unit)
 #endif
 }
 
-// Print _mjitX, but make a human-readable funcname when --jit-debug is used
+// Print _mjitX, but make a human-readable funcname when --mjit-debug is used
 static void
 sprint_funcname(char *funcname, const struct rb_mjit_unit *unit)
 {

ruby.c

@@ -103,7 +103,7 @@ void rb_warning_category_update(unsigned int mask, unsigned int bits);
     SEP \
     X(frozen_string_literal) \
     SEP \
-    X(jit) \
+    X(mjit) \
     SEP \
     X(yjit)
     /* END OF FEATURES */
@@ -220,7 +220,7 @@ enum {
 	& ~FEATURE_BIT(gems)
 #endif
 	& ~FEATURE_BIT(frozen_string_literal)
-        & ~FEATURE_BIT(jit)
+        & ~FEATURE_BIT(mjit)
         & ~FEATURE_BIT(yjit)
 	)
 };
@@ -235,7 +235,7 @@ cmdline_options_init(ruby_cmdline_options_t *opt)
     opt->intern.enc.index = -1;
     opt->features.set = DEFAULT_FEATURES;
 #ifdef MJIT_FORCE_ENABLE /* to use with: ./configure cppflags="-DMJIT_FORCE_ENABLE" */
-    opt->features.set |= FEATURE_BIT(jit);
+    opt->features.set |= FEATURE_BIT(mjit);
 #elif defined(YJIT_FORCE_ENABLE)
     opt->features.set |= FEATURE_BIT(yjit);
 #endif
@@ -291,6 +291,11 @@ usage(const char *name, int help, int highlight, int columns)
     (unsigned short)sizeof(shortopt), \
     (unsigned short)sizeof(longopt), \
 }
+#if YJIT_SUPPORTED_P
+# define PLATFORM_JIT_OPTION "--yjit"
+#else
+# define PLATFORM_JIT_OPTION "--mjit"
+#endif
     static const struct message usage_msg[] = {
 	M("-0[octal]",	   "",			   "specify record separator (\\0, if no argument)"),
 	M("-a",		   "",			   "autosplit mode with -n or -p (splits $_ into $F)"),
@@ -312,8 +317,8 @@ usage(const char *name, int help, int highlight, int columns)
 	M("-w",		   "",			   "turn warnings on for your script"),
 	M("-W[level=2|:category]",   "",	   "set warning level; 0=silence, 1=medium, 2=verbose"),
 	M("-x[directory]", "",			   "strip off text before #!ruby line and perhaps cd to directory"),
-        M("--jit",         "",                     "enable JIT with default options (experimental)"),
+        M("--jit",         "",                     "enable JIT for the platform, same as " PLATFORM_JIT_OPTION " (experimental)"),
-        M("--jit-[option]","",                     "enable JIT with an option (experimental)"),
+        M("--mjit",        "",                     "enable C compiler-based JIT compiler (experimental)"),
         M("--yjit",        "",                     "enable in-process JIT compiler (experimental)"),
 	M("-h",		   "",			   "show this message, --help for more info"),
     };
@@ -321,7 +326,7 @@ usage(const char *name, int help, int highlight, int columns)
 	M("--copyright",                            "", "print the copyright"),
 	M("--dump={insns|parsetree|...}[,...]",     "",
           "dump debug information. see below for available dump list"),
-	M("--enable={jit|rubyopt|...}[,...]", ", --disable={jit|rubyopt|...}[,...]",
+	M("--enable={mjit|rubyopt|...}[,...]", ", --disable={mjit|rubyopt|...}[,...]",
 	  "enable or disable features. see below for available features"),
 	M("--external-encoding=encoding",           ", --internal-encoding=encoding",
 	  "specify the default external or internal character encoding"),
@@ -343,7 +348,7 @@ usage(const char *name, int help, int highlight, int columns)
 	M("did_you_mean", "",   "did_you_mean (default: "DEFAULT_RUBYGEMS_ENABLED")"),
 	M("rubyopt", "",        "RUBYOPT environment variable (default: enabled)"),
 	M("frozen-string-literal", "", "freeze all string literals (default: disabled)"),
-        M("jit", "",            "JIT compiler (default: disabled)"),
+        M("mjit", "",           "C compiler-based JIT compiler (default: disabled)"),
         M("yjit", "",           "in-process JIT compiler (default: disabled)"),
     };
     static const struct message warn_categories[] = {
@@ -351,13 +356,13 @@ usage(const char *name, int help, int highlight, int columns)
         M("experimental", "",     "experimental features"),
     };
     static const struct message mjit_options[] = {
-        M("--jit-warnings",      "", "Enable printing JIT warnings"),
+        M("--mjit-warnings",      "", "Enable printing JIT warnings"),
-        M("--jit-debug",         "", "Enable JIT debugging (very slow), or add cflags if specified"),
+        M("--mjit-debug",         "", "Enable JIT debugging (very slow), or add cflags if specified"),
-        M("--jit-wait",          "", "Wait until JIT compilation finishes every time (for testing)"),
+        M("--mjit-wait",          "", "Wait until JIT compilation finishes every time (for testing)"),
-        M("--jit-save-temps",    "", "Save JIT temporary files in $TMP or /tmp (for testing)"),
+        M("--mjit-save-temps",    "", "Save JIT temporary files in $TMP or /tmp (for testing)"),
-        M("--jit-verbose=num",   "", "Print JIT logs of level num or less to stderr (default: 0)"),
+        M("--mjit-verbose=num",   "", "Print JIT logs of level num or less to stderr (default: 0)"),
-        M("--jit-max-cache=num", "", "Max number of methods to be JIT-ed in a cache (default: 100)"),
+        M("--mjit-max-cache=num", "", "Max number of methods to be JIT-ed in a cache (default: 100)"),
-        M("--jit-min-calls=num", "", "Number of calls to trigger JIT (for testing, default: 10000)"),
+        M("--mjit-min-calls=num", "", "Number of calls to trigger JIT (for testing, default: 10000)"),
     };
     static const struct message yjit_options[] = {
 #if YJIT_STATS
@@ -952,12 +957,20 @@ feature_option(const char *str, int len, void *arg, const unsigned int enable)
 #define SET_FEATURE(bit) \
     if (NAME_MATCH_P(#bit, str, len)) {set |= mask = FEATURE_BIT(bit); FEATURE_FOUND;}
     EACH_FEATURES(SET_FEATURE, ;);
+    if (NAME_MATCH_P("jit", str, len)) { // This allows you to cancel --jit
+#if defined(MJIT_FORCE_ENABLE) || !YJIT_SUPPORTED_P
+        set |= mask = FEATURE_BIT(mjit);
+#else
+        set |= mask = FEATURE_BIT(yjit);
+#endif
+        goto found;
+    }
     if (NAME_MATCH_P("all", str, len)) {
         // YJIT and MJIT cannot be enabled at the same time. We enable only YJIT for --enable=all.
-#ifdef MJIT_FORCE_ENABLE
+#if defined(MJIT_FORCE_ENABLE) || !YJIT_SUPPORTED_P
         mask &= ~(FEATURE_BIT(yjit));
 #else
-        mask &= ~(FEATURE_BIT(jit));
+        mask &= ~(FEATURE_BIT(mjit));
 #endif
         goto found;
     }
@@ -1512,10 +1525,19 @@ proc_options(long argc, char **argv, ruby_cmdline_options_t *opt, int envopt)
 		opt->verbose = 1;
 		ruby_verbose = Qtrue;
 	    }
-            else if (strncmp("jit", s, 3) == 0) {
+            else if (strcmp("jit", s) == 0) {
+#if !USE_MJIT
+                rb_warn("Ruby was built without JIT support");
+#elif defined(MJIT_FORCE_ENABLE) || !YJIT_SUPPORTED_P
+                FEATURE_SET(opt->features, FEATURE_BIT(mjit));
+#else
+                FEATURE_SET(opt->features, FEATURE_BIT(yjit));
+#endif
+            }
+            else if (strncmp("mjit", s, 4) == 0) {
 #if USE_MJIT
-                FEATURE_SET(opt->features, FEATURE_BIT(jit));
+                FEATURE_SET(opt->features, FEATURE_BIT(mjit));
-                setup_mjit_options(s + 3, &opt->mjit);
+                setup_mjit_options(s + 4, &opt->mjit);
 #else
                 rb_warn("MJIT support is disabled.");
 #endif
@@ -1888,7 +1910,7 @@ process_options(int argc, char **argv, ruby_cmdline_options_t *opt)
         rb_warning("-K is specified; it is for 1.8 compatibility and may cause odd behavior");
 
 #if USE_MJIT
-    if (opt->features.set & FEATURE_BIT(jit)) {
+    if (opt->features.set & FEATURE_BIT(mjit)) {
         opt->mjit.on = TRUE; /* set mjit.on for ruby_show_version() API and check to call mjit_init() */
     }
 #endif

template/fake.rb.in

@@ -15,7 +15,7 @@ if inc = arg['i']
     scan(/rb_define_global_const\("(RUBY_\w+)",[^;]*?\bMK(?:INT|STR)\(([^()]*)\)/m) do |n, v|
     version[n] = src.value(v)
   end
-  arg['RUBY_DESCRIPTION_WITH_JIT'] = src.value('description_with_jit')
+  arg['RUBY_DESCRIPTION_WITH_MJIT'] = src.value('description_with_mjit')
 end
 %>baseruby="<%=arg['BASERUBY']%>"
 _\

test/-ext-/bug_reporter/test_bug_reporter.rb

@@ -7,7 +7,7 @@ class TestBugReporter < Test::Unit::TestCase
     skip if ENV['RUBY_ON_BUG']
 
     description = RUBY_DESCRIPTION
-    description = description.sub(/\+JIT /, '') if defined?(RubyVM::JIT) && RubyVM::JIT.enabled?
+    description = description.sub(/\+MJIT /, '') if defined?(RubyVM::JIT) && RubyVM::JIT.enabled?
     description = description.sub(/\+YJIT /, '') if defined?(RubyVM::YJIT.enabled?) && RubyVM::YJIT.enabled?
     expected_stderr = [
       :*,

test/lib/jit_support.rb

@@ -21,7 +21,7 @@ module JITSupport
   ]
 
   module_function
-  # Run Ruby script with --jit-wait (Synchronous JIT compilation).
+  # Run Ruby script with --mjit-wait (Synchronous JIT compilation).
   # Returns [stdout, stderr]
   def eval_with_jit(env = nil, script, **opts)
     stdout, stderr = nil, nil
@@ -36,13 +36,13 @@ module JITSupport
 
   def eval_with_jit_without_retry(env = nil, script, verbose: 0, min_calls: 5, save_temps: false, max_cache: 1000, wait: true, timeout: JIT_TIMEOUT)
     args = [
-      '--disable-gems', "--jit-verbose=#{verbose}",
+      '--disable-gems', "--mjit-verbose=#{verbose}",
-      "--jit-min-calls=#{min_calls}", "--jit-max-cache=#{max_cache}",
+      "--mjit-min-calls=#{min_calls}", "--mjit-max-cache=#{max_cache}",
     ]
     args << '--disable-yjit'
-    args << '--jit-wait' if wait
+    args << '--mjit-wait' if wait
-    args << '--jit-save-temps' if save_temps
+    args << '--mjit-save-temps' if save_temps
-    args << '--jit-debug' if defined?(@jit_debug) && @jit_debug
+    args << '--mjit-debug' if defined?(@mjit_debug) && @mjit_debug
     args << '-e' << script
     base_env = { 'MJIT_SEARCH_BUILD_DIR' => 'true' } # workaround to skip requiring `make install` for `make test-all`
     if preloadenv = RbConfig::CONFIG['PRELOADENV'] and !preloadenv.empty?

test/ruby/test_jit.rb

@@ -1194,8 +1194,8 @@ class TestJIT < Test::Unit::TestCase
     out, err = eval_with_jit(script, verbose: 1, min_calls: min_calls, max_cache: max_cache)
     success_actual = err.scan(/^#{JIT_SUCCESS_PREFIX}:/).size
     recompile_actual = err.scan(/^#{JIT_RECOMPILE_PREFIX}:/).size
-    # Add --jit-verbose=2 logs for cl.exe because compiler's error message is suppressed
+    # Add --mjit-verbose=2 logs for cl.exe because compiler's error message is suppressed
-    # for cl.exe with --jit-verbose=1. See `start_process` in mjit_worker.c.
+    # for cl.exe with --mjit-verbose=1. See `start_process` in mjit_worker.c.
     if RUBY_PLATFORM.match?(/mswin/) && success_count != success_actual
       out2, err2 = eval_with_jit(script, verbose: 2, min_calls: min_calls, max_cache: max_cache)
     end

test/ruby/test_jit_debug.rb

@@ -11,7 +11,7 @@ class TestJITDebug < TestJIT
 
   def setup
     super
-    # let `#eval_with_jit` use --jit-debug
+    # let `#eval_with_jit` use --mjit-debug
-    @jit_debug = true
+    @mjit_debug = true
   end
 end

test/ruby/test_rubyoptions.rb

@@ -11,7 +11,7 @@ class TestRubyOptions < Test::Unit::TestCase
 
   NO_JIT_DESCRIPTION =
     if defined?(RubyVM::JIT) && RubyVM::JIT.enabled? # checking -DMJIT_FORCE_ENABLE
-      RUBY_DESCRIPTION.sub(/\+JIT /, '')
+      RUBY_DESCRIPTION.sub(/\+MJIT /, '')
     elsif yjit_enabled? # checking -DYJIT_FORCE_ENABLE
       RUBY_DESCRIPTION.sub(/\+YJIT /, '')
     else
@@ -137,7 +137,7 @@ class TestRubyOptions < Test::Unit::TestCase
   VERSION_PATTERN_WITH_JIT =
     case RUBY_ENGINE
     when 'ruby'
-      /^ruby #{q[RUBY_VERSION]}(?:[p ]|dev|rc).*? \+JIT \[#{q[RUBY_PLATFORM]}\]$/
+      /^ruby #{q[RUBY_VERSION]}(?:[p ]|dev|rc).*? \+MJIT \[#{q[RUBY_PLATFORM]}\]$/
     else
       VERSION_PATTERN
     end
@@ -226,9 +226,14 @@ class TestRubyOptions < Test::Unit::TestCase
     return if yjit_force_enabled?
 
     [
-      %w(--version --jit --disable=jit),
+      %w(--version --mjit --disable=mjit),
-      %w(--version --enable=jit --disable=jit),
+      %w(--version --enable=mjit --disable=mjit),
-      %w(--version --enable-jit --disable-jit),
+      %w(--version --enable-mjit --disable-mjit),
+      *([
+        %w(--version --jit --disable=jit),
+        %w(--version --enable=jit --disable=jit),
+        %w(--version --enable-jit --disable-jit),
+      ] unless RUBY_PLATFORM.start_with?('x86_64-') && RUBY_PLATFORM !~ /mswin|mingw|msys/),
     ].each do |args|
       assert_in_out_err([env] + args) do |r, e|
         assert_match(VERSION_PATTERN, r[0])
@@ -239,16 +244,21 @@ class TestRubyOptions < Test::Unit::TestCase
 
     if JITSupport.supported?
       [
-        %w(--version --jit),
+        %w(--version --mjit),
-        %w(--version --enable=jit),
+        %w(--version --enable=mjit),
-        %w(--version --enable-jit),
+        %w(--version --enable-mjit),
+        *([
+          %w(--version --jit),
+          %w(--version --enable=jit),
+          %w(--version --enable-jit),
+        ] unless RUBY_PLATFORM.start_with?('x86_64-') && RUBY_PLATFORM !~ /mswin|mingw|msys/),
       ].each do |args|
         assert_in_out_err([env] + args) do |r, e|
           assert_match(VERSION_PATTERN_WITH_JIT, r[0])
           if defined?(RubyVM::JIT) && RubyVM::JIT.enabled? # checking -DMJIT_FORCE_ENABLE
             assert_equal(RUBY_DESCRIPTION, r[0])
           else
-            assert_equal(EnvUtil.invoke_ruby([env, '--jit', '-e', 'print RUBY_DESCRIPTION'], '', true).first, r[0])
+            assert_equal(EnvUtil.invoke_ruby([env, '--mjit', '-e', 'print RUBY_DESCRIPTION'], '', true).first, r[0])
           end
           assert_equal([], e)
         end
@@ -1113,7 +1123,7 @@ class TestRubyOptions < Test::Unit::TestCase
     # mswin uses prebuilt precompiled header. Thus it does not show a pch compilation log to check "-O0 -O1".
     if JITSupport.supported? && !RUBY_PLATFORM.match?(/mswin/)
       env = { 'MJIT_SEARCH_BUILD_DIR' => 'true' }
-      assert_in_out_err([env, "--disable-yjit", "--jit-debug=-O0 -O1", "--jit-verbose=2", "" ], "", [], /-O0 -O1/)
+      assert_in_out_err([env, "--disable-yjit", "--mjit-debug=-O0 -O1", "--mjit-verbose=2", "" ], "", [], /-O0 -O1/)
     end
   end
 

test/ruby/test_yjit.rb

@@ -21,6 +21,15 @@ class TestYJIT < Test::Unit::TestCase
       %w(--version --disable=yjit --yjit),
       %w(--version --disable=yjit --enable-yjit),
       %w(--version --disable=yjit --enable=yjit),
+      *([
+        %w(--version --jit),
+        %w(--version --disable-jit --jit),
+        %w(--version --disable-jit --enable-jit),
+        %w(--version --disable-jit --enable=jit),
+        %w(--version --disable=jit --yjit),
+        %w(--version --disable=jit --enable-jit),
+        %w(--version --disable=jit --enable=jit),
+      ] if RUBY_PLATFORM.start_with?('x86_64-') && RUBY_PLATFORM !~ /mswin|mingw|msys/),
     ].each do |version_args|
       assert_in_out_err(version_args) do |stdout, stderr|
         assert_equal(RUBY_DESCRIPTION, stdout.first)

version.c

@@ -42,7 +42,7 @@ const char ruby_release_date[] = RUBY_RELEASE_DATE;
 const char ruby_platform[] = RUBY_PLATFORM;
 const int ruby_patchlevel = RUBY_PATCHLEVEL;
 const char ruby_description[] = RUBY_DESCRIPTION_WITH("");
-static const char ruby_description_with_jit[] = RUBY_DESCRIPTION_WITH(" +JIT");
+static const char ruby_description_with_mjit[] = RUBY_DESCRIPTION_WITH(" +MJIT");
 static const char ruby_description_with_yjit[] = RUBY_DESCRIPTION_WITH(" +YJIT");
 const char ruby_copyright[] = RUBY_COPYRIGHT;
 const char ruby_engine[] = "ruby";
@@ -104,7 +104,7 @@ Init_ruby_description(void)
     VALUE description;
 
     if (MJIT_OPTS_ON) {
-        description = MKSTR(description_with_jit);
+        description = MKSTR(description_with_mjit);
     }
     else if (rb_yjit_enabled_p()) {
         description = MKSTR(description_with_yjit);
@@ -123,7 +123,7 @@ void
 ruby_show_version(void)
 {
     if (MJIT_OPTS_ON) {
-        PRINT(description_with_jit);
+        PRINT(description_with_mjit);
     }
     else if (rb_yjit_enabled_p()) {
         PRINT(description_with_yjit);

win32/Makefile.sub

@@ -1322,14 +1322,14 @@ clean-local::
 	$(Q)$(RM) $(arch_hdrdir)/rb_mjit_header-*.$(OBJEXT)
 
 # Non-mswin environment is not using prebuilt precompiled header because upgrading compiler
-# or changing compiler options may break MJIT so build (currently only by --jit-debug though).
+# or changing compiler options may break MJIT so build (currently only by --mjit-debug though).
 #
 # But mswin is building precompiled header because cl.exe cannot leave macro after preprocess.
 # As a workaround to use macro without installing many source files, it uses precompiled header
 # without sufficient guard for a broken build.
 #
 # TODO: Fix the above issue by including VC version in header name, and create another header
-# for --jit-debug as well.
+# for --mjit-debug as well.
 $(TIMESTAMPDIR)/$(MJIT_PRECOMPILED_HEADER_NAME:.pch=).time: probes.h vm.$(OBJEXT)
 	$(ECHO) building $(@F:.time=.pch)
 	$(Q) $(CC) -DMJIT_HEADER $(CFLAGS: -Zi = -Z7 ) $(XCFLAGS:-DRUBY_EXPORT =) -URUBY_EXPORT $(CPPFLAGS) $(srcdir)/vm.c -c -Yc \

yjit.c

@@ -20,17 +20,11 @@
 # define YJIT_DUMP_MODE 0
 #endif
 
-#if defined(__x86_64__) && !defined(_WIN32)
-# define PLATFORM_SUPPORTED_P 1
-#else
-# define PLATFORM_SUPPORTED_P 0
-#endif
-
 // USE_MJIT comes from configure options
 #define JIT_ENABLED USE_MJIT
 
 // Check if we need to include YJIT in the build
-#if JIT_ENABLED && PLATFORM_SUPPORTED_P
+#if JIT_ENABLED && YJIT_SUPPORTED_P
 
 #include "yjit_asm.c"
 
@@ -165,7 +159,7 @@ static uint32_t yjit_codepage_frozen_bytes = 0;
 #include "yjit_codegen.c"
 
 #else
-// !JIT_ENABLED || !PLATFORM_SUPPORTED_P
+// !JIT_ENABLED || !YJIT_SUPPORTED_P
 // In these builds, YJIT could never be turned on. Provide dummy
 // implementations for YJIT functions exposed to the rest of the code base.
 // See yjit.h.
@@ -190,4 +184,4 @@ void rb_yjit_before_ractor_spawn(void) {}
 void rb_yjit_constant_ic_update(const rb_iseq_t *const iseq, IC ic) {}
 void rb_yjit_tracing_invalidate_all(void) {}
 
-#endif // if JIT_ENABLED && PLATFORM_SUPPORTED_P
+#endif // if JIT_ENABLED && YJIT_SUPPORTED_P

yjit.h

@@ -15,6 +15,13 @@
 # define YJIT_STATS RUBY_DEBUG
 #endif
 
+// We generate x86 assembly and rely on mmap(2).
+#if defined(__x86_64__) && !defined(_WIN32)
+# define YJIT_SUPPORTED_P 1
+#else
+# define YJIT_SUPPORTED_P 0
+#endif
+
 struct rb_yjit_options {
     // Enable compilation with YJIT
     bool yjit_enabled;

yjit_iface.c

@@ -1233,7 +1233,7 @@ outgoing_ids(VALUE self)
 void
 rb_yjit_init(struct rb_yjit_options *options)
 {
-    if (!PLATFORM_SUPPORTED_P || !JIT_ENABLED) {
+    if (!YJIT_SUPPORTED_P || !JIT_ENABLED) {
         return;
     }