https://git.ruby-lang.org/ruby.git/commit/?id=c08d4067be

From c08d4067be83d03a6fcd173ffd2d206a01d09c90 Mon Sep 17 00:00:00 2001
From: Peter Zhu <peter@p...>
Date: Tue, 24 Aug 2021 13:14:14 -0400
Subject: [Feature #18045] Remove T_PAYLOAD

This commit removes T_PAYLOAD since the new VWA implementation no longer
requires T_PAYLOAD types.

Co-authored-by: Aaron Patterson <tenderlove@r...>
---
 ext/objspace/objspace.c            |   2 -
 gc.c                               | 345 +------------------------------------
 include/ruby/internal/value_type.h |   2 -
 internal/gc.h                      |   4 -
 misc/lldb_cruby.py                 |   3 -
 vm_eval.c                          |   1 -
 6 files changed, 2 insertions(+), 355 deletions(-)

diff --git a/ext/objspace/objspace.c b/ext/objspace/objspace.c
index 72d1eb8..3fa4fd2 100644
--- a/ext/objspace/objspace.c
+++ b/ext/objspace/objspace.c
@@ -66,7 +66,6 @@ total_i(VALUE v, void *ptr) https://github.com/ruby/ruby/blob/trunk/ext/objspace/objspace.c#L66
       case T_IMEMO:
       case T_ICLASS:
       case T_NODE:
-      case T_PAYLOAD:
       case T_ZOMBIE:
           return;
       default:
@@ -225,7 +224,6 @@ type2sym(enum ruby_value_type i) https://github.com/ruby/ruby/blob/trunk/ext/objspace/objspace.c#L224
 	CASE_TYPE(T_ICLASS);
         CASE_TYPE(T_MOVED);
 	CASE_TYPE(T_ZOMBIE);
-	CASE_TYPE(T_PAYLOAD);
 #undef CASE_TYPE
       default: rb_bug("type2sym: unknown type (%d)", i);
     }
diff --git a/gc.c b/gc.c
index 0c35625..e410178 100644
--- a/gc.c
+++ b/gc.c
@@ -556,7 +556,6 @@ typedef struct gc_profile_record { https://github.com/ruby/ruby/blob/trunk/gc.c#L556
 } gc_profile_record;
 
 #define FL_FROM_FREELIST FL_USER0
-#define FL_FROM_PAYLOAD FL_USER0
 
 struct RMoved {
     VALUE flags;
@@ -570,31 +569,12 @@ struct RMoved { https://github.com/ruby/ruby/blob/trunk/gc.c#L569
 #pragma pack(push, 4) /* == SIZEOF_VALUE: magic for reducing sizeof(RVALUE): 24 -> 20 */
 #endif
 
-struct RPayload {
-    VALUE flags;
-};
-#define RPAYLOAD(obj) ((struct RPayload *)obj)
-static unsigned short
-RPAYLOAD_LEN(VALUE obj)
-{
-    unsigned short len = (unsigned short)(RPAYLOAD(obj)->flags >> FL_USHIFT);
-    return len;
-}
-
-static void
-RPAYLOAD_FLAGS_SET(VALUE obj, unsigned short len)
-{
-    // as len is the only thing in the user bits, we can overwrite it every time
-    RPAYLOAD(obj)->flags = T_PAYLOAD | (len << FL_USHIFT);
-}
-
 typedef struct RVALUE {
     union {
 	struct {
 	    VALUE flags;		/* always 0 for freed obj */
 	    struct RVALUE *next;
 	} free;
-        struct RPayload payload;
         struct RMoved  moved;
 	struct RBasic  basic;
 	struct RObject object;
@@ -1290,36 +1270,6 @@ RVALUE_FLAGS_AGE(VALUE flags) https://github.com/ruby/ruby/blob/trunk/gc.c#L1270
     return (int)((flags & (FL_PROMOTED0 | FL_PROMOTED1)) >> RVALUE_AGE_SHIFT);
 }
 
-#if USE_RVARGC
-static VALUE
-payload_or_self(VALUE obj)
-{
-    struct heap_page *p = GET_HEAP_PAGE(obj);
-    VALUE cur = (VALUE)p->start;
-
-    while (cur != obj && GET_HEAP_PAGE(cur) == p) {
-        VALUE p = cur;
-        void *poisoned = asan_poisoned_object_p((VALUE)p);
-        asan_unpoison_object((VALUE)p, false);
-
-        if (BUILTIN_TYPE(cur) == T_PAYLOAD) {
-            if (cur < obj && obj < cur + RPAYLOAD_LEN(cur) * sizeof(RVALUE)) {
-                return cur;
-            }
-            cur += RPAYLOAD_LEN(cur) * sizeof(RVALUE);
-        }
-        else {
-            cur += sizeof(RVALUE);
-        }
-        if (poisoned) {
-            asan_poison_object((VALUE)p);
-        }
-    }
-
-    return obj;
-}
-#endif
-
 static int
 check_rvalue_consistency_force(const VALUE obj, int terminate)
 {
@@ -1527,18 +1477,6 @@ RVALUE_PAGE_OLD_UNCOLLECTIBLE_SET(rb_objspace_t *objspace, struct heap_page *pag https://github.com/ruby/ruby/blob/trunk/gc.c#L1477
 {
     MARK_IN_BITMAP(&page->uncollectible_bits[0], obj);
     objspace->rgengc.old_objects++;
-
-#if USE_RVARGC
-    if (BUILTIN_TYPE(obj) == T_PAYLOAD) {
-        int plen = RPAYLOAD_LEN(obj);
-
-        for (int i = 1; i < plen; i++) {
-            VALUE pbody = obj + i * sizeof(RVALUE);
-            MARK_IN_BITMAP(GET_HEAP_UNCOLLECTIBLE_BITS(pbody), pbody);
-        }
-        objspace->rgengc.old_objects += plen - 1;
-    }
-#endif
     rb_transient_heap_promote(obj);
 
 #if RGENGC_PROFILE >= 2
@@ -1628,11 +1566,6 @@ RVALUE_DEMOTE(rb_objspace_t *objspace, VALUE obj) https://github.com/ruby/ruby/blob/trunk/gc.c#L1566
 
     if (RVALUE_MARKED(obj)) {
 	objspace->rgengc.old_objects--;
-#if USE_RVARGC
-        if (BUILTIN_TYPE(obj) == T_PAYLOAD) {
-            objspace->rgengc.old_objects -= RPAYLOAD_LEN(obj) - 1;
-        }
-#endif
     }
 
     check_rvalue_consistency(obj);
@@ -2255,136 +2188,11 @@ newobj_init(VALUE klass, VALUE flags, int wb_protected, rb_objspace_t *objspace, https://github.com/ruby/ruby/blob/trunk/gc.c#L2188
     return obj;
 }
 
-static unsigned long
-rvargc_slot_count(size_t size)
-{
-    // roomof == ceiling division, so we don't have to do div then mod
-    return roomof(size + sizeof(struct RPayload), sizeof(RVALUE));
-}
-
-#if USE_RVARGC
-static RVALUE *
-rvargc_find_contiguous_slots(int slots, RVALUE *freelist)
-{
-    RVALUE *cursor = freelist;
-    RVALUE *previous_region = NULL;
-
-    while (cursor) {
-        int i;
-        RVALUE *search = cursor;
-        for (i = 0; i < (slots - 1); i++) {
-
-            // Peek ahead to see if the region is contiguous
-            if (search->as.free.next == (search - 1)) {
-                search = search->as.free.next;
-            }
-            else {
-                // Next slot is not contiguous
-                if (search->as.free.next) {
-                    cursor = search->as.free.next;
-                    previous_region = search;
-
-                    break;
-                }
-                else {
-                    // Hit the end of the free list
-                    return NULL;
-                }
-            }
-        }
-
-        if (i == slots - 1) {
-            if (previous_region) {
-                previous_region->as.free.next = search->as.free.next;
-                search->as.free.next = freelist;
-            }
-            return search;
-        }
-    }
-    rb_bug("rvargc_find_contiguous_slots: unreachable");
-}
-#endif
-
 static inline void heap_add_freepage(rb_heap_t *heap, struct heap_page *page);
 static struct heap_page * heap_next_freepage(rb_objspace_t *objspace, rb_heap_t *heap);
 static inline void ractor_set_cache(rb_ractor_t *cr, struct heap_page *page);
 
 #if USE_RVARGC
-static inline void *
-rvargc_find_region(size_t size, rb_ractor_t *cr, RVALUE *freelist)
-{
-    // maintain master behaviour when we only need one slot
-    if (size == sizeof(RVALUE))
-        return freelist;
-
-    if (!freelist) return freelist;
-
-    rb_objspace_t *objspace = &rb_objspace;
-    int slots = (int)rvargc_slot_count(size);
-    RVALUE * p = rvargc_find_contiguous_slots(slots, freelist);
-
-    // We found a contiguous space on the freelist stored in the ractor cache
-    if (p) {
-        struct heap_page *page = GET_HEAP_PAGE(p);
-
-        page->free_slots -= slots;
-        asan_unpoison_memory_region(p, sizeof(RVALUE) * slots, false);
-        return p;
-    }
-    else {
-        struct heap_page *search_page;
-        heap_allocatable_pages_set(objspace, heap_allocatable_pages + 1);
-
-        while (!p) {
-            // search_page is the page we're going to search for contiguous slots
-            search_page = heap_next_freepage(objspace, heap_eden);
-            p = rvargc_find_contiguous_slots(slots, search_page->freelist);
-
-            if (p) {
-                // Remove the region from the freelist
-                search_page->freelist = p->as.free.next;
-                search_page->free_slots -= slots;
-
-                // If we started sweeping, the object cache can be removed
-                // from the ractor.  Set it to the page we found
-                if (!cr->newobj_cache.using_page) {
-                    ractor_set_cache(cr, search_page);
-                }
-                // Otherwise we need to add this page back to the list of free
-                // pages.
-                else {
-                    // make this pointer point at the Ractor's freelist
-                    p->as.free.next = freelist;
-                }
-
-                asan_unpoison_memory_region(p, sizeof(RVALUE) * slots, false);
-                return p;
-            }
-        }
-    }
-    return NULL;
-}
-#endif
-
-int
-rb_slot_size(void)
-{
-    return sizeof(RVALUE);
-}
-
-VALUE
-rb_rvargc_payload_init(VALUE obj, size_t size)
-{
-    rb_objspace_t * objspace = &rb_objspace;
-    struct RPayload *ph = (struct RPayload *)obj;
-    memset(ph, 0, rvargc_slot_count(size) * sizeof(RVALUE));
-
-    RPAYLOAD_FLAGS_SET((VALUE)ph, rvargc_slot_count(size));
-    objspace->total_allocated_objects += rvargc_slot_count(size);
-
-    return (VALUE)ph;
-}
-
 void *
 rb_rvargc_payload_data_ptr(VALUE phead)
 {
@@ -2394,11 +2202,7 @@ rb_rvargc_payload_data_ptr(VALUE phead) https://github.com/ruby/ruby/blob/trunk/gc.c#L2202
 static inline VALUE
 ractor_cached_free_region(rb_objspace_t *objspace, rb_ractor_t *cr, size_t size)
 {
-#if USE_RVARGC
-    RVALUE *p = rvargc_find_region(size, cr, cr->newobj_cache.freelist);
-#else
     RVALUE *p = cr->newobj_cache.freelist;
-#endif
 
     if (p) {
         VALUE obj = (VALUE)p;
@@ -2496,10 +2300,6 @@ newobj_slowpath(VALUE klass, VALUE flags, rb_objspace_t *objspace, rb_ractor_t * https://github.com/ruby/ruby/blob/trunk/gc.c#L2300
         }
         GC_ASSERT(obj != 0);
         newobj_init(klass, flags, wb_protected, objspace, obj);
-#if USE_RVARGC
-        if (alloc_size > sizeof(RVALUE))
-            rb_rvargc_payload_init(obj + sizeof(RVALUE), alloc_size - sizeof(RVALUE));
-#endif
 
         gc_event_hook_prep(objspace, RUBY_INTERNAL_EVENT_NEWOBJ, obj, newobj_fill(obj, 0, 0, 0));
     }
@@ -2550,10 +2350,6 @@ newobj_of0(VALUE klass, VALU (... truncated)

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