1 files changed, 34 insertions, 21 deletions

diff --git a/include/ruby/internal/core/rmatch.h b/include/ruby/internal/core/rmatch.h
index a528c2999e..ae93755531 100644
--- a/include/ruby/internal/core/rmatch.h
+++ b/include/ruby/internal/core/rmatch.h
@@ -67,23 +67,6 @@ struct rmatch_offset {
     long end; /**< End of a group. */
 };
 
-/** Represents a match. */
-struct rb_matchext_struct {
-    /**
-     * "Registers"  of a  match.   This  is a  quasi-opaque  struct that  holds
-     * execution result of a match.  Roughly resembles `&~`.
-     */
-    struct re_registers regs;
-
-    /** Capture group offsets, in C array. */
-    struct rmatch_offset *char_offset;
-
-    /** Number of ::rmatch_offset that ::rmatch::char_offset holds. */
-    int char_offset_num_allocated;
-};
-
-typedef struct rb_matchext_struct rb_matchext_t;
-
 /**
  * Regular expression  execution context.  When a  regular expression "matches"
  * to a string, it generates capture  groups etc.  This struct holds that info.
@@ -107,12 +90,41 @@ struct RMatch {
      * The expression of this match.
      */
     VALUE regexp;  /* RRegexp */
+
+    /** Number of ::rmatch_offset that ::rmatch::char_offset holds. */
+    int char_offset_num_allocated;
+
+    /** Capture group offsets, in C array. */
+    struct rmatch_offset *char_offset;
+
+    /** Number of capture-group registers. */
+    int num_regs;
+
+    /** Capacity of `as.embed`, in OnigPosition slots. */
+    int capa;
+
+    /**
+     * "Registers" of a match.  This is a quasi-opaque struct that holds
+     * execution result of a match.  Roughly resembles `$~`.
+     */
+    union {
+        OnigPosition embed[1];
+        struct re_registers onig;
+    } as;
 };
 
-#define RMATCH_EXT(m) ((rb_matchext_t *)((char *)(m) + sizeof(struct RMatch)))
+RBIMPL_SYMBOL_EXPORT_BEGIN()
+/**
+ * @private
+ *
+ * Converts an  embedded match  to onig  form.  This  is an  implementation
+ * detail of #RMATCH_REGS.  People don't use it directly.
+ *
+ * @param[out]  match  A match object, possibly in embedded form.
+ */
+void rb_match_ensure_onig(VALUE match);
+RBIMPL_SYMBOL_EXPORT_END()
 
-RBIMPL_ATTR_PURE_UNLESS_DEBUG()
-RBIMPL_ATTR_ARTIFICIAL()
 /**
  * Queries the raw ::re_registers.
  *
@@ -138,7 +150,8 @@ static inline struct re_registers *
 RMATCH_REGS(VALUE match)
 {
     RBIMPL_ASSERT_TYPE(match, RUBY_T_MATCH);
-    return &RMATCH_EXT(match)->regs;
+    rb_match_ensure_onig(match);
+    return &RMATCH(match)->as.onig;
 }
 
 #endif /* RBIMPL_RMATCH_H */