Struct tree common

概要

• gcc-4.1.0/gcc/tree.hにて定義
• 全ての struct tree_* 型の先頭に存在し，大量のフラグ情報を持つ構造体．

実装

• GTY というマクロは，読むぶんには，とりあえずは無視してかまわないらしい．

241 /* The definition of tree nodes fills the next several pages.  */
242 
243 /* A tree node can represent a data type, a variable, an expression
244    or a statement.  Each node has a TREE_CODE which says what kind o f
245    thing it represents.  Some common codes are:
246    INTEGER_TYPE -- represents a type of integers.
247    ARRAY_TYPE -- represents a type of pointer.
248    VAR_DECL -- represents a declared variable.
249    INTEGER_CST -- represents a constant integer value.
250    PLUS_EXPR -- represents a sum (an expression).
251 
252    As for the contents of a tree node: there are some fields
253    that all nodes share.  Each TREE_CODE has various special-purpose
254    fields as well.  The fields of a node are never accessed directly,
255    always through accessor macros.  */
256 
257 /* Every kind of tree node starts with this structure,
258    so all nodes have these fields.
259 
260    See the accessor macros, defined below, for documentation of the
261    fields.  */
262 union tree_ann_d;
263 
264 struct tree_common GTY(())
265 {

• tree は，union tree_node へのポインタ．

266   tree chain;
267   tree type;
268   union tree_ann_d *ann;
269

• tree_code は，enum tree_code

270   ENUM_BITFIELD(tree_code) code : 8;
271 
272   unsigned side_effects_flag : 1;
273   unsigned constant_flag : 1;
274   unsigned addressable_flag : 1;
275   unsigned volatile_flag : 1;
276   unsigned readonly_flag : 1;
277   unsigned unsigned_flag : 1;
278   unsigned asm_written_flag: 1;
279   unsigned nowarning_flag : 1;
280 
281   unsigned used_flag : 1;
282   unsigned nothrow_flag : 1;
283   unsigned static_flag : 1;
284   unsigned public_flag : 1;
285   unsigned private_flag : 1;
286   unsigned protected_flag : 1;
287   unsigned deprecated_flag : 1;
288   unsigned invariant_flag : 1;
289 
290   unsigned lang_flag_0 : 1;
291   unsigned lang_flag_1 : 1;
292   unsigned lang_flag_2 : 1;
293   unsigned lang_flag_3 : 1;
294   unsigned lang_flag_4 : 1;
295   unsigned lang_flag_5 : 1;
296   unsigned lang_flag_6 : 1;
297   unsigned visited : 1;
298 };

code メンバの説明は，J 03_12_17] が参考になります．

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