Simplify around `USE_YJIT` macro (#6240)

* Simplify around `USE_YJIT` macro

- Use `USE_YJIT` macro only instead of `YJIT_BUILD`.
- An intermediate macro `YJIT_SUPPORTED_P` is no longer used.

* Bail out if YJIT is enabled on unsupported platforms

1 files changed, 7 insertions, 16 deletions

diff --git a/yjit.h b/yjit.h
index cf420df251..1f507f1b51 100644
--- a/yjit.h
+++ b/yjit.h
@@ -15,24 +15,15 @@
 # define YJIT_STATS RUBY_DEBUG
 #endif
 
-// We generate x86 assembly
-#if (defined(__x86_64__) && !defined(_WIN32)) || (defined(_WIN32) && defined(_M_AMD64)) // x64 platforms without mingw/msys
-# define YJIT_SUPPORTED_P 1
-#else
-# define YJIT_SUPPORTED_P 0
-#endif
+#if USE_YJIT
 
-// Is the output binary going to include YJIT?
-#if USE_MJIT && USE_YJIT && YJIT_SUPPORTED_P
-# define YJIT_BUILD 1
+// We generate x86 assembly
+#if defined(_WIN32) ? defined(_M_AMD64) : defined(__x86_64__)
+// x86_64 platforms without mingw/msys or x64-mswin
 #else
-# define YJIT_BUILD 0
+# error YJIT unsupported platform
 #endif
 
-#undef YJIT_SUPPORTED_P
-
-#if YJIT_BUILD
-
 // Expose these as declarations since we are building YJIT.
 bool rb_yjit_enabled_p(void);
 unsigned rb_yjit_call_threshold(void);
@@ -54,7 +45,7 @@ void rb_yjit_constant_ic_update(const rb_iseq_t *const iseq, IC ic);
 void rb_yjit_tracing_invalidate_all(void);
 
 #else
-// !YJIT_BUILD
+// !USE_YJIT
 // In these builds, YJIT could never be turned on. Provide dummy implementations.
 
 static inline bool rb_yjit_enabled_p(void) { return false; }
@@ -76,6 +67,6 @@ static inline void rb_yjit_before_ractor_spawn(void) {}
 static inline void rb_yjit_constant_ic_update(const rb_iseq_t *const iseq, IC ic) {}
 static inline void rb_yjit_tracing_invalidate_all(void) {}
 
-#endif // #if YJIT_BUILD
+#endif // #if USE_YJIT
 
 #endif // #ifndef YJIT_H