Use ID instead of GENTRY for gvars. (#3278)

Use ID instead of GENTRY for gvars.

Global variables are compiled into GENTRY (a pointer to struct
rb_global_entry). This patch replace this GENTRY to ID and
make the code simple.

We need to search GENTRY from ID every time (st_lookup), so
additional overhead will be introduced.
However, the performance of accessing global variables is not
important now a day and this simplicity helps Ractor development.

10 files changed, 68 insertions, 178 deletions

diff --git a/compile.c b/compile.c
index ccb079c5e0..dfa3802579 100644
--- a/compile.c
+++ b/compile.c
@@ -2318,13 +2318,6 @@ iseq_set_sequence(rb_iseq_t *iseq, LINK_ANCHOR *const anchor)
 		      case TS_ID: /* ID */
 			generated_iseq[code_index + 1 + j] = SYM2ID(operands[j]);
 			break;
-		      case TS_GENTRY:
-			{
-			    struct rb_global_entry *entry =
-				(struct rb_global_entry *)(operands[j] & (~1));
-			    generated_iseq[code_index + 1 + j] = (VALUE)entry;
-			}
-			break;
 		      case TS_FUNCPTR:
 			generated_iseq[code_index + 1 + j] = operands[j];
 			break;
@@ -4875,7 +4868,7 @@ defined_expr0(rb_iseq_t *iseq, LINK_ANCHOR *const ret,
       case NODE_GVAR:
         ADD_INSN(ret, line, putnil);
         ADD_INSN3(ret, line, defined, INT2FIX(DEFINED_GVAR),
-		  ID2SYM(node->nd_entry->id), needstr);
+		  ID2SYM(node->nd_entry), needstr);
         return;
 
       case NODE_CVAR:
@@ -5262,7 +5255,7 @@ compile_named_capture_assign(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE
     LABEL *fail_label = NEW_LABEL(line), *end_label = NEW_LABEL(line);
 
 #if !(defined(NAMED_CAPTURE_BY_SVAR) && NAMED_CAPTURE_BY_SVAR-0)
-    ADD_INSN1(ret, line, getglobal, ((VALUE)rb_global_entry(idBACKREF) | 1));
+    ADD_INSN1(ret, line, getglobal, ID2SYM(idBACKREF));
 #else
     ADD_INSN2(ret, line, getspecial, INT2FIX(1) /* '~' */, INT2FIX(0));
 #endif
@@ -7599,8 +7592,7 @@ iseq_compile_each0(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *node, in
 	if (!popped) {
 	    ADD_INSN(ret, line, dup);
 	}
-	ADD_INSN1(ret, line, setglobal,
-		  ((VALUE)node->nd_entry | 1));
+	ADD_INSN1(ret, line, setglobal, ID2SYM(node->nd_entry));
 	break;
       }
       case NODE_IASGN:{
@@ -8212,8 +8204,7 @@ iseq_compile_each0(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *node, in
 	break;
       }
       case NODE_GVAR:{
-	ADD_INSN1(ret, line, getglobal,
-		  ((VALUE)node->nd_entry | 1));
+	ADD_INSN1(ret, line, getglobal, ID2SYM(node->nd_entry));
 	if (popped) {
 	    ADD_INSN(ret, line, pop);
 	}
@@ -8980,13 +8971,6 @@ insn_data_to_s_detail(INSN *iobj)
 	      case TS_ID:	/* ID */
 		rb_str_concat(str, opobj_inspect(OPERAND_AT(iobj, j)));
 		break;
-	      case TS_GENTRY:
-		{
-		    struct rb_global_entry *entry = (struct rb_global_entry *)
-		      (OPERAND_AT(iobj, j) & (~1));
-		    rb_str_append(str, rb_id2str(entry->id));
-		    break;
-		}
 	      case TS_IC:	/* inline cache */
 	      case TS_IVC:	/* inline ivar cache */
 	      case TS_ISE:	/* inline storage entry */
@@ -9376,10 +9360,6 @@ iseq_build_from_ary_body(rb_iseq_t *iseq, LINK_ANCHOR *const anchor,
 			    }
 			}
 			break;
-		      case TS_GENTRY:
-			op = rb_to_symbol_type(op);
-			argv[j] = (VALUE)rb_global_entry(SYM2ID(op));
-			break;
 		      case TS_ISE:
                         FL_SET((VALUE)iseq, ISEQ_MARKABLE_ISEQ);
                         /* fall through */
@@ -10136,19 +10116,6 @@ ibf_dump_iseq(struct ibf_dump *dump, const rb_iseq_t *iseq)
     }
 }
 
-static VALUE
-ibf_dump_gentry(struct ibf_dump *dump, const struct rb_global_entry *entry)
-{
-    return (VALUE)ibf_dump_id(dump, entry->id);
-}
-
-static VALUE
-ibf_load_gentry(const struct ibf_load *load, const struct rb_global_entry *entry)
-{
-    ID gid = ibf_load_id(load, (ID)(VALUE)entry);
-    return (VALUE)rb_global_entry(gid);
-}
-
 static unsigned char
 ibf_load_byte(const struct ibf_load *load, ibf_offset_t *offset)
 {
@@ -10316,9 +10283,6 @@ ibf_dump_code(struct ibf_dump *dump, const rb_iseq_t *iseq)
               case TS_ID:
                 wv = ibf_dump_id(dump, (ID)op);
                 break;
-              case TS_GENTRY:
-                wv = ibf_dump_gentry(dump, (const struct rb_global_entry *)op);
-                break;
               case TS_FUNCPTR:
                 rb_raise(rb_eRuntimeError, "TS_FUNCPTR is not supported");
                 goto skip_wv;
@@ -10403,12 +10367,6 @@ ibf_load_code(const struct ibf_load *load, rb_iseq_t *iseq, ibf_offset_t bytecod
                     code[code_index] = ibf_load_id(load, (ID)(VALUE)op);
                 }
                 break;
-              case TS_GENTRY:
-                {
-                    VALUE op = ibf_load_small_value(load, &reading_pos);
-                    code[code_index] = ibf_load_gentry(load, (const struct rb_global_entry *)(VALUE)op);
-                }
-                break;
               case TS_FUNCPTR:
                 rb_raise(rb_eRuntimeError, "TS_FUNCPTR is not supported");
                 break;
diff --git a/insns.def b/insns.def
index 95f13915a5..c4e80040b6 100644
--- a/insns.def
+++ b/insns.def
@@ -288,25 +288,23 @@ setconstant
 /* get global variable id. */
 DEFINE_INSN
 getglobal
-(GENTRY entry)
+(ID gid)
 ()
 (VALUE val)
-// attr bool leaf = leafness_of_getglobal(entry);
+// attr bool leaf = false;
 {
-    struct rb_global_entry *gentry = (void *)entry;
-    val = rb_gvar_get(gentry);
+    val = rb_gvar_get(gid);
 }
 
 /* set global variable id as val. */
 DEFINE_INSN
 setglobal
-(GENTRY entry)
+(ID gid)
 (VALUE val)
 ()
-// attr bool leaf = leafness_of_setglobal(entry);
+// attr bool leaf = false;
 {
-    struct rb_global_entry *gentry = (void *)entry;
-    rb_gvar_set(gentry, val);
+    rb_gvar_set(gid, val);
 }
 
 /**********************************************************/
diff --git a/internal/variable.h b/internal/variable.h
index f0b7b215a4..6ed728076e 100644
--- a/internal/variable.h
+++ b/internal/variable.h
@@ -19,13 +19,6 @@
 
 #define ROBJECT_TRANSIENT_FLAG    FL_USER13
 
-struct rb_global_variable;      /* defined in variable.c */
-
-struct rb_global_entry {
-    struct rb_global_variable *var;
-    ID id;
-};
-
 /* variable.c */
 void rb_gc_mark_global_tbl(void);
 void rb_gc_update_global_tbl(void);
@@ -36,9 +29,8 @@ VALUE rb_ivar_lookup(VALUE obj, ID id, VALUE undef);
 void rb_autoload_str(VALUE mod, ID id, VALUE file);
 VALUE rb_autoload_at_p(VALUE, ID, int);
 NORETURN(VALUE rb_mod_const_missing(VALUE,VALUE));
-rb_gvar_getter_t *rb_gvar_getter_function_of(const struct rb_global_entry *);
-rb_gvar_setter_t *rb_gvar_setter_function_of(const struct rb_global_entry *);
-bool rb_gvar_is_traced(const struct rb_global_entry *);
+rb_gvar_getter_t *rb_gvar_getter_function_of(ID);
+rb_gvar_setter_t *rb_gvar_setter_function_of(ID);
 void rb_gvar_readonly_setter(VALUE v, ID id, VALUE *_);
 static inline bool ROBJ_TRANSIENT_P(VALUE obj);
 static inline void ROBJ_TRANSIENT_SET(VALUE obj);
@@ -55,11 +47,9 @@ void rb_deprecate_constant(VALUE mod, const char *name);
 RUBY_SYMBOL_EXPORT_END
 
 MJIT_SYMBOL_EXPORT_BEGIN
-struct rb_global_entry *rb_global_entry(ID);
-VALUE rb_gvar_get(struct rb_global_entry *);
-VALUE rb_gvar_set(struct rb_global_entry *, VALUE);
-VALUE rb_gvar_defined(struct rb_global_entry *);
-struct st_table *rb_ivar_generic_ivtbl(void);
+VALUE rb_gvar_get(ID);
+VALUE rb_gvar_set(ID, VALUE);
+VALUE rb_gvar_defined(ID);
 void rb_const_warn_if_deprecated(const rb_const_entry_t *, VALUE, ID);
 MJIT_SYMBOL_EXPORT_END
 
diff --git a/iseq.c b/iseq.c
index 956bd2a697..e6568a6a2e 100644
--- a/iseq.c
+++ b/iseq.c
@@ -1946,12 +1946,6 @@ rb_insn_operand_intern(const rb_iseq_t *iseq,
 	    }
 	    break;
 	}
-      case TS_GENTRY:
-	{
-	    struct rb_global_entry *entry = (struct rb_global_entry *)op;
-	    ret = rb_str_dup(rb_id2str(entry->id));
-	}
-	break;
 
       case TS_IC:
       case TS_IVC:
@@ -2776,12 +2770,6 @@ iseq_data_to_ary(const rb_iseq_t *iseq)
 		    }
 		}
 		break;
-	      case TS_GENTRY:
-		{
-		    struct rb_global_entry *entry = (struct rb_global_entry *)*seq;
-		    rb_ary_push(ary, ID2SYM(entry->id));
-		}
-		break;
 	      case TS_IC:
               case TS_IVC:
 	      case TS_ISE:
diff --git a/node.c b/node.c
index 4ef18db544..7a2fce1997 100644
--- a/node.c
+++ b/node.c
@@ -63,7 +63,7 @@
 #define SIMPLE_FIELD1(name, ann)    SIMPLE_FIELD(FIELD_NAME_LEN(name, ann), FIELD_NAME_DESC(name, ann))
 #define F_CUSTOM1(name, ann)	    SIMPLE_FIELD1(#name, ann)
 #define F_ID(name, ann) 	    SIMPLE_FIELD1(#name, ann) A_ID(node->name)
-#define F_GENTRY(name, ann)	    SIMPLE_FIELD1(#name, ann) A_ID((node->name)->id)
+#define F_GENTRY(name, ann)	    SIMPLE_FIELD1(#name, ann) A_ID(node->name)
 #define F_INT(name, ann)	    SIMPLE_FIELD1(#name, ann) A_INT(node->name)
 #define F_LONG(name, ann)	    SIMPLE_FIELD1(#name, ann) A_LONG(node->name)
 #define F_LIT(name, ann)	    SIMPLE_FIELD1(#name, ann) A_LIT(node->name)
diff --git a/node.h b/node.h
index 60e9604f46..84c5d09b83 100644
--- a/node.h
+++ b/node.h
@@ -164,7 +164,6 @@ typedef struct RNode {
 	struct RNode *node;
 	ID id;
 	long state;
-	struct rb_global_entry *entry;
 	struct rb_args_info *args;
 	struct rb_ary_pattern_info *apinfo;
 	struct rb_fnd_pattern_info *fpinfo;
@@ -228,7 +227,7 @@ typedef struct RNode {
 
 #define nd_stts  u1.node
 
-#define nd_entry u3.entry
+#define nd_entry u3.id
 #define nd_vid   u1.id
 #define nd_cflag u2.id
 #define nd_cval  u3.value
@@ -316,7 +315,7 @@ typedef struct RNode {
 #define NEW_ZLIST(loc) NEW_NODE(NODE_ZLIST,0,0,0,loc)
 #define NEW_HASH(a,loc)  NEW_NODE(NODE_HASH,a,0,0,loc)
 #define NEW_MASGN(l,r,loc)   NEW_NODE(NODE_MASGN,l,0,r,loc)
-#define NEW_GASGN(v,val,loc) NEW_NODE(NODE_GASGN,v,val,rb_global_entry(v),loc)
+#define NEW_GASGN(v,val,loc) NEW_NODE(NODE_GASGN,v,val,v,loc)
 #define NEW_LASGN(v,val,loc) NEW_NODE(NODE_LASGN,v,val,0,loc)
 #define NEW_DASGN(v,val,loc) NEW_NODE(NODE_DASGN,v,val,0,loc)
 #define NEW_DASGN_CURR(v,val,loc) NEW_NODE(NODE_DASGN_CURR,v,val,0,loc)
@@ -329,7 +328,7 @@ typedef struct RNode {
 #define NEW_OP_ASGN_OR(i,val,loc) NEW_NODE(NODE_OP_ASGN_OR,i,val,0,loc)
 #define NEW_OP_ASGN_AND(i,val,loc) NEW_NODE(NODE_OP_ASGN_AND,i,val,0,loc)
 #define NEW_OP_CDECL(v,op,val,loc) NEW_NODE(NODE_OP_CDECL,v,val,op,loc)
-#define NEW_GVAR(v,loc) NEW_NODE(NODE_GVAR,v,0,rb_global_entry(v),loc)
+#define NEW_GVAR(v,loc) NEW_NODE(NODE_GVAR,v,0,v,loc)
 #define NEW_LVAR(v,loc) NEW_NODE(NODE_LVAR,v,0,0,loc)
 #define NEW_DVAR(v,loc) NEW_NODE(NODE_DVAR,v,0,0,loc)
 #define NEW_IVAR(v,loc) NEW_NODE(NODE_IVAR,v,0,0,loc)
diff --git a/tool/ruby_vm/models/typemap.rb b/tool/ruby_vm/models/typemap.rb
index c4b13f67f9..ed3aea7d2e 100644
--- a/tool/ruby_vm/models/typemap.rb
+++ b/tool/ruby_vm/models/typemap.rb
@@ -14,7 +14,6 @@ RubyVM::Typemap = {
   "..."            => %w[. TS_VARIABLE],
   "CALL_DATA"      => %w[C TS_CALLDATA],
   "CDHASH"         => %w[H TS_CDHASH],
-  "GENTRY"         => %w[G TS_GENTRY],
   "IC"             => %w[K TS_IC],
   "IVC"            => %w[A TS_IVC],
   "ID"             => %w[I TS_ID],
diff --git a/tool/ruby_vm/views/_leaf_helpers.erb b/tool/ruby_vm/views/_leaf_helpers.erb
index ac60f2dcbc..2637f8777d 100644
--- a/tool/ruby_vm/views/_leaf_helpers.erb
+++ b/tool/ruby_vm/views/_leaf_helpers.erb
@@ -8,63 +8,6 @@
 %;
 #line <%= __LINE__ + 1 %> <%=cstr __FILE__ %>
 
-static bool
-leafness_of_getglobal(VALUE gentry)
-{
-    const struct rb_global_entry *e = (void *)gentry;
-
-    if (UNLIKELY(rb_gvar_is_traced(e))) {
-        return false;
-    }
-    else {
-        /* We cannot write this function using a switch() because a
-         * case label cannot be a function pointer. */
-        static rb_gvar_getter_t *const allowlist[] = {
-            rb_gvar_val_getter,
-            rb_gvar_var_getter,
-            /* rb_gvar_undef_getter issues rb_warning() */
-        };
-        rb_gvar_getter_t *f = rb_gvar_getter_function_of(e);
-        int i;
-
-        for (i = 0; i < numberof(allowlist); i++) {
-            if (f == allowlist[i]) {
-                return true;
-            }
-        }
-        return false;
-    }
-}
-
-static bool
-leafness_of_setglobal(VALUE gentry)
-{
-    const struct rb_global_entry *e = (void *)gentry;
-
-    if (UNLIKELY(rb_gvar_is_traced(e))) {
-        return false;
-    }
-    else {
-        /* We cannot write this function using a switch() because a
-         * case label cannot be a function pointer. */
-        static rb_gvar_setter_t *const allowlist[] = {
-            rb_gvar_val_setter,
-            /* rb_gvar_readonly_setter issues rb_name_error() */
-            rb_gvar_var_setter,
-            rb_gvar_undef_setter,
-        };
-        rb_gvar_setter_t *f = rb_gvar_setter_function_of(e);
-        int i;
-
-        for (i = 0; i < numberof(allowlist); i++) {
-            if (f == allowlist[i]) {
-                return true;
-            }
-        }
-        return false;
-    }
-}
-
 #include "iseq.h"
 
 static bool
diff --git a/variable.c b/variable.c
index 4d62361fd0..5d3785b346 100644
--- a/variable.c
+++ b/variable.c
@@ -325,13 +325,24 @@ struct rb_global_variable {
     struct trace_var *trace;
 };
 
+struct rb_global_entry {
+    struct rb_global_variable *var;
+    ID id;
+};
+
+static struct rb_id_table *
+global_tbl(void)
+{
+    return rb_global_tbl;
+}
+
 static struct rb_global_entry*
 rb_find_global_entry(ID id)
 {
     struct rb_global_entry *entry;
     VALUE data;
 
-    if (!rb_id_table_lookup(rb_global_tbl, id, &data)) {
+    if (!rb_id_table_lookup(global_tbl(), id, &data)) {
         return NULL;
     }
     entry = (struct rb_global_entry *)data;
@@ -344,7 +355,7 @@ rb_gvar_undef_compactor(void *var)
 {
 }
 
-MJIT_FUNC_EXPORTED struct rb_global_entry*
+static struct rb_global_entry*
 rb_global_entry(ID id)
 {
     struct rb_global_entry *entry = rb_find_global_entry(id);
@@ -363,7 +374,7 @@ rb_global_entry(ID id)
 
 	var->block_trace = 0;
 	var->trace = 0;
-	rb_id_table_insert(rb_global_tbl, id, (VALUE)entry);
+	rb_id_table_insert(global_tbl(), id, (VALUE)entry);
     }
     return entry;
 }
@@ -472,8 +483,9 @@ mark_global_entry(VALUE v, void *ignored)
 void
 rb_gc_mark_global_tbl(void)
 {
-    if (rb_global_tbl)
+    if (rb_global_tbl) {
         rb_id_table_foreach_values(rb_global_tbl, mark_global_entry, 0);
+    }
 }
 
 static enum rb_id_table_iterator_result
@@ -640,7 +652,7 @@ rb_f_untrace_var(int argc, const VALUE *argv)
     if (!id) {
 	rb_name_error_str(var, "undefined global variable %"PRIsVALUE"", QUOTE(var));
     }
-    if (!rb_id_table_lookup(rb_global_tbl, id, &data)) {
+    if (!rb_id_table_lookup(global_tbl(), id, &data)) {
 	rb_name_error(id, "undefined global variable %"PRIsVALUE"", QUOTE_ID(id));
     }
 
@@ -671,13 +683,6 @@ rb_f_untrace_var(int argc, const VALUE *argv)
     return Qnil;
 }
 
-MJIT_FUNC_EXPORTED VALUE
-rb_gvar_get(struct rb_global_entry *entry)
-{
-    struct rb_global_variable *var = entry->var;
-    return (*var->getter)(entry->id, var->data);
-}
-
 struct trace_data {
     struct trace_var *trace;
     VALUE val;
@@ -706,8 +711,8 @@ trace_en(VALUE v)
     return Qnil;		/* not reached */
 }
 
-MJIT_FUNC_EXPORTED VALUE
-rb_gvar_set(struct rb_global_entry *entry, VALUE val)
+static VALUE
+rb_gvar_set_entry(struct rb_global_entry *entry, VALUE val)
 {
     struct trace_data trace;
     struct rb_global_variable *var = entry->var;
@@ -724,54 +729,63 @@ rb_gvar_set(struct rb_global_entry *entry, VALUE val)
 }
 
 VALUE
-rb_gv_set(const char *name, VALUE val)
+rb_gvar_set(ID id, VALUE val)
 {
     struct rb_global_entry *entry;
+    entry = rb_global_entry(id);
+
+    return rb_gvar_set_entry(entry, val);
+}
 
-    entry = rb_global_entry(global_id(name));
-    return rb_gvar_set(entry, val);
+VALUE
+rb_gv_set(const char *name, VALUE val)
+{
+    return rb_gvar_set(global_id(name), val);
+}
+
+VALUE
+rb_gvar_get(ID id)
+{
+    struct rb_global_entry *entry = rb_global_entry(id);
+    struct rb_global_variable *var = entry->var;
+    return (*var->getter)(entry->id, var->data);
 }
 
 VALUE
 rb_gv_get(const char *name)
 {
-    struct rb_global_entry *entry;
     ID id = find_global_id(name);
-
+    
     if (!id) {
         rb_warning("global variable `%s' not initialized", name);
         return Qnil;
     }
 
-    entry = rb_global_entry(id);
-    return rb_gvar_get(entry);
+    return rb_gvar_get(id);
 }
 
 MJIT_FUNC_EXPORTED VALUE
-rb_gvar_defined(struct rb_global_entry *entry)
+rb_gvar_defined(ID id)
 {
+    struct rb_global_entry *entry = rb_global_entry(id);
     if (entry->var->getter == rb_gvar_undef_getter) return Qfalse;
     return Qtrue;
 }
 
 rb_gvar_getter_t *
-rb_gvar_getter_function_of(const struct rb_global_entry *entry)
+rb_gvar_getter_function_of(ID id)
 {
+    const struct rb_global_entry *entry = rb_global_entry(id);
     return entry->var->getter;
 }
 
 rb_gvar_setter_t *
-rb_gvar_setter_function_of(const struct rb_global_entry *entry)
+rb_gvar_setter_function_of(ID id)
 {
+    const struct rb_global_entry *entry = rb_global_entry(id);
     return entry->var->setter;
 }
 
-bool
-rb_gvar_is_traced(const struct rb_global_entry *entry)
-{
-    return !!entry->var->trace;
-}
-
 static enum rb_id_table_iterator_result
 gvar_i(ID key, VALUE val, void *a)
 {
@@ -786,7 +800,7 @@ rb_f_global_variables(void)
     VALUE ary = rb_ary_new();
     VALUE sym, backref = rb_backref_get();
 
-    rb_id_table_foreach(rb_global_tbl, gvar_i, (void *)ary);
+    rb_id_table_foreach(global_tbl(), gvar_i, (void *)ary);
     if (!NIL_P(backref)) {
 	char buf[2];
 	int i, nmatch = rb_match_count(backref);
@@ -813,12 +827,13 @@ rb_alias_variable(ID name1, ID name2)
 {
     struct rb_global_entry *entry1, *entry2;
     VALUE data1;
+    struct rb_id_table *gtbl = global_tbl();
 
     entry2 = rb_global_entry(name2);
-    if (!rb_id_table_lookup(rb_global_tbl, name1, &data1)) {
+    if (!rb_id_table_lookup(gtbl, name1, &data1)) {
 	entry1 = ALLOC(struct rb_global_entry);
 	entry1->id = name1;
-	rb_id_table_insert(rb_global_tbl, name1, (VALUE)entry1);
+	rb_id_table_insert(gtbl, name1, (VALUE)entry1);
     }
     else if ((entry1 = (struct rb_global_entry *)data1)->var != entry2->var) {
 	struct rb_global_variable *var = entry1->var;
diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index cacddc2b0e..f2cab2f4b5 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -3661,7 +3661,7 @@ vm_defined(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, rb_num_t op_
 	klass = vm_get_cbase(GET_EP());
 	break;
       case DEFINED_GVAR:
-	if (rb_gvar_defined(rb_global_entry(SYM2ID(obj)))) {
+	if (rb_gvar_defined(SYM2ID(obj))) {
 	    expr_type = DEFINED_GVAR;
 	}
 	break;