experiment: dump segments size

Author: byroot

ext/objspace/objspace_dump.c

@@ -461,6 +461,14 @@ dump_object(VALUE obj, struct dump_config *dc)
             }
             break;
 
+          case imemo_iseq: {
+                size_t segment_size = rb_iseq_ic_segments_size((const rb_iseq_t *)obj);
+                if (segment_size) {
+                    dump_append(dc, ", \"segments_memsize\":");
+                    dump_append_sizet(dc, segment_size);
+                }
+                break;
+            }
           default:
             break;
         }

iseq.c

@@ -504,6 +504,29 @@ rb_iseq_memsize(const rb_iseq_t *iseq)
     return size;
 }
 
+size_t
+rb_iseq_ic_segments_size(const rb_iseq_t *iseq)
+{
+    size_t size = 0;
+    const struct rb_iseq_constant_body *body = ISEQ_BODY(iseq);
+
+    if (ISEQ_EXECUTABLE_P(iseq) && body) {
+        if (ISEQ_BODY(iseq)->is_entries) {
+            /* IC entries constant segments */
+            for (unsigned int ic_idx = 0; ic_idx < body->ic_size; ic_idx++) {
+                IC ic = &ISEQ_IS_IC_ENTRY(body, ic_idx);
+                const ID *ids = ic->segments;
+                if (!ids) continue;
+                while (*ids++) {
+                    size += sizeof(ID);
+                }
+                size += sizeof(ID); // null terminator
+            }
+        }
+    }
+    return size;
+}
+
 struct rb_iseq_constant_body *
 rb_iseq_constant_body_alloc(void)
 {

vm_core.h

@@ -590,6 +590,7 @@ static inline const rb_iseq_t *rb_iseq_complete(const rb_iseq_t *iseq) {return 0
 #endif
 const rb_iseq_t *rb_iseq_complete(const rb_iseq_t *iseq);
 
+
 static inline const rb_iseq_t *
 rb_iseq_check(const rb_iseq_t *iseq)
 {
@@ -1213,6 +1214,8 @@ typedef enum {
 /* iseq.c */
 RUBY_SYMBOL_EXPORT_BEGIN
 
+size_t rb_iseq_ic_segments_size(const rb_iseq_t *iseq);
+
 /* node -> iseq */
 rb_iseq_t *rb_iseq_new         (const VALUE ast_value, VALUE name, VALUE path, VALUE realpath,                   const rb_iseq_t *parent, enum rb_iseq_type);
 rb_iseq_t *rb_iseq_new_top     (const VALUE ast_value, VALUE name, VALUE path, VALUE realpath,                   const rb_iseq_t *parent);