Manage AST NODEs out of GC

NODEs in AST are no longer objects managed by GC.  This change will
remove the restriction imposed by the GC.  For example, a NODE can use
more than five words (this is my primary purpose; we want to store the
position data for each NODE, for coverage library), or even a NODE can
have variable length (some kinds of NODEs have unused fields).
To do this, however, we need more work, since Ripper still uses T_NODE
objects managed by the GC.

The life time of NODEs is more obvious than other kinds of objects; they
are created at parsing, and they become disused immediately after
compilation.  This change releases all NODEs by a few `xfree`s after
compilation, so performance will be improved a bit.  In extreme example,
`eval("x=1;" * 10000000)` runs much faster (40 sec. -> 7.8 sec. on my
machine).

The most important part of this change is `ast_t` struct, which has
three contents: (1) NODE buffer (malloc'ed memory), (2) a reference to
the root NODE, and (3) an array that contains objects that must be
marked during parsing (such as literal objects).  Some functions that
had received `NODE*` arguments, must now receive `ast_t*`.

* node.c, node.h: defines `ast_t` struct and related operations.
* gc.c, internal.h: defines `imemo_ast`.
* parse.y: makes `parser_params` struct have a reference to `ast_t`.
  Instead of `rb_node_newnode`, use `rb_ast_newnode` to create a NODE.
* iseq.c, load.c, ruby.c, template/prelude.c.tmpl: modifies some
  functions to handle `ast_t*` instead of `NODE*`.
* test/ruby/test_gc.rb: ad-hoc fix for a failed test.  The test assumes
  GC eden is increased at startup by NODE object creation.  However,
  this change now create no NODE object, so GC eden is not necessarily
  increased.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60485 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 55 insertions, 25 deletions

diff --git a/parse.y b/parse.y
index 082365dac2..cb3849e28e 100644
--- a/parse.y
+++ b/parse.y
@@ -239,6 +239,7 @@ struct parser_params {
     unsigned int do_chomp: 1;
     unsigned int do_split: 1;
 
+    ast_t *ast;
     NODE *eval_tree_begin;
     NODE *eval_tree;
     VALUE error_buffer;
@@ -338,15 +339,27 @@ parser_set_line(NODE *n, int l)
 }
 
 static inline void
-rb_discard_node(NODE *n)
+rb_discard_node_gen(struct parser_params *parser, NODE *n)
 {
+#ifndef RIPPER
+    rb_ast_delete_node(parser->ast, n);
+#else
     rb_gc_force_recycle((VALUE)n);
+#endif
 }
-
-#define add_mark_object(obj) (void)(obj)
+#define rb_discard_node(n) rb_discard_node_gen(parser, (n))
 
 #ifndef RIPPER
 static inline void
+add_mark_object_gen(struct parser_params *parser, VALUE obj)
+{
+    if (!SPECIAL_CONST_P(obj)) {
+	rb_ast_add_mark_object(parser->ast, obj);
+    }
+}
+#define add_mark_object(obj) add_mark_object_gen(parser, (obj))
+
+static inline void
 set_line_body(NODE *body, int line)
 {
     if (!body) return;
@@ -575,6 +588,8 @@ static NODE *parser_heredoc_dedent(struct parser_params*,NODE*);
 #else  /* RIPPER */
 #define NODE_RIPPER NODE_CDECL
 
+#define add_mark_object(obj) (void)(obj)
+
 static inline VALUE
 ripper_new_yylval(ID a, VALUE b, VALUE c)
 {
@@ -2850,6 +2865,7 @@ primary		: literal
 				break;
 			    }
 			}
+			add_mark_object((VALUE)rb_imemo_alloc_new((VALUE)tbl, 0, 0, 0));
 			scope = NEW_NODE(NODE_SCOPE, tbl, $8, args);
 			nd_set_column(scope, @1.first_column);
 			tbl[0] = 1; tbl[1] = id;
@@ -5573,52 +5589,55 @@ lex_getline(struct parser_params *parser)
 static const rb_data_type_t parser_data_type;
 
 #ifndef RIPPER
-static NODE*
+static ast_t*
 parser_compile_string(VALUE vparser, VALUE fname, VALUE s, int line)
 {
     struct parser_params *parser;
-    NODE *node;
+    ast_t *ast;
 
     TypedData_Get_Struct(vparser, struct parser_params, &parser_data_type, parser);
+    parser->ast = ast = rb_ast_new();
+
     lex_gets = lex_get_str;
     lex_gets_ptr = 0;
     lex_input = rb_str_new_frozen(s);
     lex_pbeg = lex_p = lex_pend = 0;
 
-    node = yycompile(parser, fname, line);
+    ast->root = yycompile(parser, fname, line);
+    parser->ast = 0;
     RB_GC_GUARD(vparser); /* prohibit tail call optimization */
 
-    return node;
+    return ast;
 }
 
-NODE*
+ast_t*
 rb_compile_string(const char *f, VALUE s, int line)
 {
     must_be_ascii_compatible(s);
     return parser_compile_string(rb_parser_new(), rb_filesystem_str_new_cstr(f), s, line);
 }
 
-NODE*
+ast_t*
 rb_parser_compile_string(VALUE vparser, const char *f, VALUE s, int line)
 {
     return rb_parser_compile_string_path(vparser, rb_filesystem_str_new_cstr(f), s, line);
 }
 
-NODE*
+ast_t*
 rb_parser_compile_string_path(VALUE vparser, VALUE f, VALUE s, int line)
 {
     must_be_ascii_compatible(s);
     return parser_compile_string(vparser, f, s, line);
 }
 
-NODE*
+ast_t*
 rb_compile_cstr(const char *f, const char *s, int len, int line)
 {
     VALUE str = rb_str_new(s, len);
     return parser_compile_string(rb_parser_new(), rb_filesystem_str_new_cstr(f), str, line);
 }
 
-NODE*
+ast_t*
 rb_parser_compile_cstr(VALUE vparser, const char *f, const char *s, int len, int line)
 {
     VALUE str = rb_str_new(s, len);
@@ -5633,7 +5652,7 @@ lex_io_gets(struct parser_params *parser, VALUE io)
     return rb_io_gets_internal(io);
 }
 
-NODE*
+ast_t*
 rb_compile_file(const char *f, VALUE file, int start)
 {
     VALUE vparser = rb_parser_new();
@@ -5641,27 +5660,30 @@ rb_compile_file(const char *f, VALUE file, int start)
     return rb_parser_compile_file(vparser, f, file, start);
 }
 
-NODE*
+ast_t*
 rb_parser_compile_file(VALUE vparser, const char *f, VALUE file, int start)
 {
     return rb_parser_compile_file_path(vparser, rb_filesystem_str_new_cstr(f), file, start);
 }
 
-NODE*
+ast_t*
 rb_parser_compile_file_path(VALUE vparser, VALUE fname, VALUE file, int start)
 {
     struct parser_params *parser;
-    NODE *node;
+    ast_t *ast;
 
     TypedData_Get_Struct(vparser, struct parser_params, &parser_data_type, parser);
+    parser->ast = ast = rb_ast_new();
+
     lex_gets = lex_io_gets;
     lex_input = file;
     lex_pbeg = lex_p = lex_pend = 0;
 
-    node = yycompile(parser, fname, start);
+    ast->root = yycompile(parser, fname, start);
+    parser->ast = 0;
     RB_GC_GUARD(vparser); /* prohibit tail call optimization */
 
-    return node;
+    return ast;
 }
 #endif  /* !RIPPER */
 
@@ -6160,8 +6182,11 @@ parser_regx_options(struct parser_params *parser)
 }
 
 static void
-dispose_string(VALUE str)
+dispose_string(struct parser_params *parser, VALUE str)
 {
+#ifndef RIPPER
+    rb_ast_delete_mark_object(parser->ast, str);
+#endif
     rb_str_free(str);
     rb_gc_force_recycle(str);
 }
@@ -6639,7 +6664,7 @@ parser_heredoc_restore(struct parser_params *parser, NODE *here)
     lex_p = lex_pbeg + here->nd_nth;
     heredoc_end = ruby_sourceline;
     ruby_sourceline = nd_line(here);
-    dispose_string(here->nd_lit);
+    dispose_string(parser, here->nd_lit);
     rb_discard_node(here);
     token_flush(parser);
 }
@@ -6925,7 +6950,7 @@ parser_here_document(struct parser_params *parser, NODE *here)
 	    }
 	    if (nextc() == -1) {
 		if (str) {
-		    dispose_string(str);
+		    dispose_string(parser, str);
 		    str = 0;
 		}
 		goto error;
@@ -8800,7 +8825,10 @@ yylex(YYSTYPE *lval, YYLTYPE *yylloc, struct parser_params *parser)
 static NODE*
 node_newnode(struct parser_params *parser, enum node_type type, VALUE a0, VALUE a1, VALUE a2)
 {
-    NODE *n = (rb_node_newnode)(type, a0, a1, a2);
+    NODE *n = rb_ast_newnode(parser->ast);
+
+    rb_node_init(n, type, a0, a1, a2);
+
     nd_set_line(n, ruby_sourceline);
     /* mark not cared column to -1 */
     nd_set_column(n, -1);
@@ -10590,6 +10618,7 @@ new_args_tail_gen(struct parser_params *parser, NODE *k, ID kr, ID b, int column
     NODE *node;
 
     args = ZALLOC(struct rb_args_info);
+    add_mark_object((VALUE)rb_imemo_alloc_new((VALUE)args, 0, 0, 0));
     node = NEW_NODE(NODE_ARGS, 0, 0, args);
     nd_set_column(node, column);
     if (parser->error_p) return node;
@@ -10959,6 +10988,9 @@ local_tbl_gen(struct parser_params *parser)
     }
     if (--j < cnt) REALLOC_N(buf, ID, (cnt = j) + 1);
     buf[0] = cnt;
+
+    add_mark_object((VALUE)rb_imemo_alloc_new((VALUE)buf, 0, 0, 0));
+
     return buf;
 }
 #endif
@@ -11350,18 +11382,16 @@ parser_mark(void *ptr)
 {
     struct parser_params *parser = (struct parser_params*)ptr;
 
-    rb_gc_mark((VALUE)lex_strterm);
     rb_gc_mark(lex_input);
     rb_gc_mark(lex_lastline);
     rb_gc_mark(lex_nextline);
     rb_gc_mark(ruby_sourcefile_string);
 #ifndef RIPPER
-    rb_gc_mark((VALUE)ruby_eval_tree_begin);
-    rb_gc_mark((VALUE)ruby_eval_tree);
     rb_gc_mark(ruby_debug_lines);
     rb_gc_mark(parser->compile_option);
     rb_gc_mark(parser->error_buffer);
 #else
+    rb_gc_mark((VALUE)lex_strterm);
     rb_gc_mark(parser->delayed);
     rb_gc_mark(parser->value);
     rb_gc_mark(parser->result);