Adding `GC.compact` and compacting GC support.

This commit adds the new method `GC.compact` and compacting GC support.
Please see this issue for caveats:

  https://bugs.ruby-lang.org/issues/15626

[Feature #15626]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67479 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 19 insertions, 4 deletions

diff --git a/include/ruby/intern.h b/include/ruby/intern.h
index 17aafd7f8e..192347c8d5 100644
--- a/include/ruby/intern.h
+++ b/include/ruby/intern.h
@@ -507,10 +507,15 @@ COLDFUNC NORETURN(void rb_memerror(void));
 PUREFUNC(int rb_during_gc(void));
 void rb_gc_mark_locations(const VALUE*, const VALUE*);
 void rb_mark_tbl(struct st_table*);
+void rb_mark_tbl_no_pin(struct st_table*);
+void rb_gc_update_tbl_refs(st_table *ptr);
 void rb_mark_set(struct st_table*);
 void rb_mark_hash(struct st_table*);
+void rb_update_st_references(struct st_table *ht);
 void rb_gc_mark_maybe(VALUE);
 void rb_gc_mark(VALUE);
+void rb_gc_mark_no_pin(VALUE);
+VALUE rb_gc_new_location(VALUE);
 void rb_gc_force_recycle(VALUE);
 void rb_gc(void);
 void rb_gc_copy_finalizer(VALUE,VALUE);
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index 11387b540a..b22c4e3f2e 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -512,6 +512,7 @@ enum ruby_value_type {
     RUBY_T_NODE   = 0x1b,
     RUBY_T_ICLASS = 0x1c,
     RUBY_T_ZOMBIE = 0x1d,
+    RUBY_T_MOVED  = 0x1e,
 
     RUBY_T_MASK   = 0x1f
 };
@@ -542,6 +543,7 @@ enum ruby_value_type {
 #define T_UNDEF  RUBY_T_UNDEF
 #define T_NODE   RUBY_T_NODE
 #define T_ZOMBIE RUBY_T_ZOMBIE
+#define T_MOVED RUBY_T_MOVED
 #define T_MASK   RUBY_T_MASK
 
 #define RB_BUILTIN_TYPE(x) (int)(((struct RBasic*)(x))->flags & RUBY_T_MASK)
@@ -881,9 +883,14 @@ enum ruby_fl_type {
     RUBY_FL_SINGLETON = RUBY_FL_USER0
 };
 
+struct RMoved {
+    VALUE flags;
+    VALUE destination;
+};
+
 struct RUBY_ALIGNAS(SIZEOF_VALUE) RBasic {
     VALUE flags;
-    const VALUE klass;
+    VALUE klass;
 };
 
 VALUE rb_obj_hide(VALUE obj);
@@ -1105,7 +1112,7 @@ struct RArray {
 struct RRegexp {
     struct RBasic basic;
     struct re_pattern_buffer *ptr;
-    const VALUE src;
+    VALUE src;
     unsigned long usecnt;
 };
 #define RREGEXP_PTR(r) (RREGEXP(r)->ptr)
@@ -1144,7 +1151,8 @@ struct rb_data_type_struct {
 	void (*dmark)(void*);
 	void (*dfree)(void*);
 	size_t (*dsize)(const void *);
-	void *reserved[2]; /* For future extension.
+        void (*dcompact)(void*);
+        void *reserved[1]; /* For future extension.
 			      This array *must* be filled with ZERO. */
     } function;
     const rb_data_type_t *parent;
@@ -1255,6 +1263,7 @@ int rb_big_sign(VALUE);
 #define RBIGNUM_NEGATIVE_P(b) (RBIGNUM_SIGN(b)==0)
 
 #define R_CAST(st)   (struct st*)
+#define RMOVED(obj)  (R_CAST(RMoved)(obj))
 #define RBASIC(obj)  (R_CAST(RBasic)(obj))
 #define ROBJECT(obj) (R_CAST(RObject)(obj))
 #define RCLASS(obj)  (R_CAST(RClass)(obj))
diff --git a/include/ruby/st.h b/include/ruby/st.h
index 149e0ebaef..a7eb0c6d7c 100644
--- a/include/ruby/st.h
+++ b/include/ruby/st.h
@@ -96,7 +96,7 @@ struct st_table {
 
 #define st_is_member(table,key) st_lookup((table),(key),(st_data_t *)0)
 
-enum st_retval {ST_CONTINUE, ST_STOP, ST_DELETE, ST_CHECK};
+enum st_retval {ST_CONTINUE, ST_STOP, ST_DELETE, ST_CHECK, ST_REPLACE};
 
 st_table *st_init_table(const struct st_hash_type *);
 st_table *st_init_table_with_size(const struct st_hash_type *, st_index_t);
@@ -118,6 +118,7 @@ typedef int st_update_callback_func(st_data_t *key, st_data_t *value, st_data_t
  * results of hash() are same and compare() returns 0, otherwise the
  * behavior is undefined */
 int st_update(st_table *table, st_data_t key, st_update_callback_func *func, st_data_t arg);
+int st_foreach_with_replace(st_table *tab, int (*func)(ANYARGS), st_update_callback_func *replace, st_data_t arg);
 int st_foreach(st_table *, int (*)(ANYARGS), st_data_t);
 int st_foreach_check(st_table *, int (*)(ANYARGS), st_data_t, st_data_t);
 st_index_t st_keys(st_table *table, st_data_t *keys, st_index_t size);