1/* Data structures and functions for streaming trees.
2
3 Copyright (C) 2011-2017 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@google.com>
5
6This file is part of GCC.
7
8GCC is free software; you can redistribute it and/or modify it under
9the terms of the GNU General Public License as published by the Free
10Software Foundation; either version 3, or (at your option) any later
11version.
12
13GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14WARRANTY; without even the implied warranty of MERCHANTABILITY or
15FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16for more details.
17
18You should have received a copy of the GNU General Public License
19along with GCC; see the file COPYING3. If not see
20<http://www.gnu.org/licenses/>. */
21
22#ifndef GCC_TREE_STREAMER_H
23#define GCC_TREE_STREAMER_H
24
25#include "streamer-hooks.h"
26#include "data-streamer.h"
27
28/* Cache of pickled nodes. Used to avoid writing the same node more
29 than once. The first time a tree node is streamed out, it is
30 entered in this cache. Subsequent references to the same node are
31 resolved by looking it up in this cache.
32
33 This is used in two ways:
34
35 - On the writing side, the first time T is added to STREAMER_CACHE,
36 a new reference index is created for T and T is emitted on the
37 stream. If T needs to be emitted again to the stream, instead of
38 pickling it again, the reference index is emitted.
39
40 - On the reading side, the first time T is read from the stream, it
41 is reconstructed in memory and a new reference index created for
42 T. The reconstructed T is inserted in some array so that when
43 the reference index for T is found in the input stream, it can be
44 used to look up into the array to get the reconstructed T. */
45
46struct streamer_tree_cache_d
47{
48 /* The mapping between tree nodes and slots into the nodes array. */
49 hash_map<tree, unsigned> *node_map;
50
51 /* The nodes pickled so far. */
52 vec<tree> nodes;
53 /* The node hashes (if available). */
54 vec<hashval_t> hashes;
55
56 /* Next index to assign. */
57 unsigned next_idx;
58};
59
60/* In tree-streamer-in.c. */
61tree streamer_read_string_cst (struct data_in *, struct lto_input_block *);
62tree streamer_read_chain (struct lto_input_block *, struct data_in *);
63tree streamer_alloc_tree (struct lto_input_block *, struct data_in *,
64 enum LTO_tags);
65void streamer_read_tree_body (struct lto_input_block *, struct data_in *, tree);
66tree streamer_get_pickled_tree (struct lto_input_block *, struct data_in *);
67void streamer_read_tree_bitfields (struct lto_input_block *,
68 struct data_in *, tree);
69
70/* In tree-streamer-out.c. */
71void streamer_write_string_cst (struct output_block *,
72 struct lto_output_stream *, tree);
73void streamer_write_chain (struct output_block *, tree, bool);
74void streamer_write_tree_header (struct output_block *, tree);
75void streamer_write_tree_bitfields (struct output_block *, tree);
76void streamer_write_tree_body (struct output_block *, tree, bool);
77void streamer_write_integer_cst (struct output_block *, tree, bool);
78
79/* In tree-streamer.c. */
80extern unsigned char streamer_mode_table[1 << 8];
81void streamer_check_handled_ts_structures (void);
82bool streamer_tree_cache_insert (struct streamer_tree_cache_d *, tree,
83 hashval_t, unsigned *);
84void streamer_tree_cache_replace_tree (struct streamer_tree_cache_d *, tree,
85 unsigned);
86void streamer_tree_cache_append (struct streamer_tree_cache_d *, tree,
87 hashval_t);
88bool streamer_tree_cache_lookup (struct streamer_tree_cache_d *, tree,
89 unsigned *);
90struct streamer_tree_cache_d *streamer_tree_cache_create (bool, bool, bool);
91void streamer_tree_cache_delete (struct streamer_tree_cache_d *);
92
93/* Return the tree node at slot IX in CACHE. */
94
95static inline tree
96streamer_tree_cache_get_tree (struct streamer_tree_cache_d *cache, unsigned ix)
97{
98 return cache->nodes[ix];
99}
100
101/* Return the tree hash value at slot IX in CACHE. */
102
103static inline hashval_t
104streamer_tree_cache_get_hash (struct streamer_tree_cache_d *cache, unsigned ix)
105{
106 return cache->hashes[ix];
107}
108
109static inline void
110bp_pack_machine_mode (struct bitpack_d *bp, machine_mode mode)
111{
112 streamer_mode_table[mode] = 1;
113 bp_pack_enum (bp, machine_mode, 1 << 8, mode);
114}
115
116static inline machine_mode
117bp_unpack_machine_mode (struct bitpack_d *bp)
118{
119 return (machine_mode)
120 ((struct lto_input_block *)
121 bp->stream)->mode_table[bp_unpack_enum (bp, machine_mode, 1 << 8)];
122}
123
124#endif /* GCC_TREE_STREAMER_H */
125