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cbe34bb5 | 1 | /* Copyright (C) 2013-2017 Free Software Foundation, Inc. |
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2 | |
3 | This file is part of GCC. | |
4 | ||
5 | GCC is free software; you can redistribute it and/or modify it under | |
6 | the terms of the GNU General Public License as published by the Free | |
7 | Software Foundation; either version 3, or (at your option) any later | |
8 | version. | |
9 | ||
10 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
11 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
12 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
13 | for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with GCC; see the file COPYING3. If not see | |
17 | <http://www.gnu.org/licenses/>. */ | |
18 | ||
19 | /* Virtual Table Pointer Security. */ | |
20 | ||
21 | #ifndef VTABLE_VERIFY_H | |
22 | #define VTABLE_VERIFY_H | |
23 | ||
24 | #include "sbitmap.h" | |
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25 | |
26 | /* The function decl used to create calls to __VLTVtableVerify. It must | |
27 | be global because it needs to be initialized in the C++ front end, but | |
28 | used in the middle end (in the vtable verification pass). */ | |
29 | ||
30 | extern tree verify_vtbl_ptr_fndecl; | |
31 | ||
32 | /* Global variable keeping track of how many vtable map variables we | |
33 | have created. */ | |
34 | extern unsigned num_vtable_map_nodes; | |
35 | ||
36 | /* Keep track of how many virtual calls we are actually verifying. */ | |
37 | extern int total_num_virtual_calls; | |
38 | extern int total_num_verified_vcalls; | |
39 | ||
40 | /* Each vtable map variable corresponds to a virtual class. Each | |
41 | vtable map variable has a hash table associated with it, that keeps | |
42 | track of the vtable pointers for which we have generated a call to | |
43 | __VLTRegisterPair (with the current vtable map variable). This is | |
44 | the hash table node that is used for each entry in this hash table | |
45 | of vtable pointers. | |
46 | ||
47 | Sometimes there are multiple valid vtable pointer entries that use | |
48 | the same vtable pointer decl with different offsets. Therefore, | |
49 | for each vtable pointer in the hash table, there is also an array | |
50 | of offsets used with that vtable. */ | |
51 | ||
52 | struct vtable_registration | |
53 | { | |
54 | tree vtable_decl; /* The var decl of the vtable. */ | |
55 | vec<unsigned> offsets; /* The offsets array. */ | |
56 | }; | |
57 | ||
8d67ee55 | 58 | struct registration_hasher : nofree_ptr_hash <struct vtable_registration> |
2077db1b | 59 | { |
67f58944 TS |
60 | static inline hashval_t hash (const vtable_registration *); |
61 | static inline bool equal (const vtable_registration *, | |
62 | const vtable_registration *); | |
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63 | }; |
64 | ||
c203e8a7 | 65 | typedef hash_table<registration_hasher> register_table_type; |
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66 | typedef register_table_type::iterator registration_iterator_type; |
67 | ||
68 | /* This struct is used to represent the class hierarchy information | |
69 | that we need. Each vtable map variable has an associated class | |
70 | hierarchy node (struct vtv_graph_node). Note: In this struct, | |
71 | 'children' means immediate descendants in the class hierarchy; | |
72 | 'descendant' means any descendant however many levels deep. */ | |
73 | ||
74 | struct vtv_graph_node { | |
75 | tree class_type; /* The record_type of the class. */ | |
76 | unsigned class_uid; /* A unique, monotonically | |
77 | ascending id for class node. | |
78 | Each vtable map node also has | |
79 | an id. The class uid is the | |
80 | same as the vtable map node id | |
81 | for nodes corresponding to the | |
82 | same class. */ | |
83 | unsigned num_processed_children; /* # of children for whom we have | |
84 | computed the class hierarchy | |
85 | transitive closure. */ | |
86 | vec<struct vtv_graph_node *> parents; /* Vector of parents in the graph. */ | |
87 | vec<struct vtv_graph_node *> children; /* Vector of children in the graph.*/ | |
88 | sbitmap descendants; /* Bitmap representing all this node's | |
89 | descendants in the graph. */ | |
90 | }; | |
91 | ||
92 | /* This is the node used for our hashtable of vtable map variable | |
93 | information. When we create a vtable map variable (var decl) we | |
94 | put it into one of these nodes; create a corresponding | |
95 | vtv_graph_node for our class hierarchy info and store that in this | |
96 | node; generate a unique (monotonically ascending) id for both the | |
97 | vtbl_map_node and the vtv_graph_node; and insert the node into two | |
98 | data structures (to make it easy to find in several different | |
99 | ways): 1). A hash table ("vtbl_map_hash" in vtable-verify.c). | |
100 | This gives us an easy way to check to see if we already have a node | |
101 | for the vtable map variable or not; and 2). An array (vector) of | |
102 | vtbl_map_nodes, where the array index corresponds to the unique id | |
103 | of the vtbl_map_node, which gives us an easy way to use bitmaps to | |
104 | represent and find the vtable map nodes. */ | |
105 | ||
106 | struct vtbl_map_node { | |
107 | tree vtbl_map_decl; /* The var decl for the vtable map | |
108 | variable. */ | |
109 | tree class_name; /* The DECL_ASSEMBLER_NAME of the | |
110 | class. */ | |
111 | struct vtv_graph_node *class_info; /* Our class hierarchy info for the | |
112 | class. */ | |
113 | unsigned uid; /* The unique id for the vtable map | |
114 | variable. */ | |
115 | struct vtbl_map_node *next, *prev; /* Pointers for the linked list | |
116 | structure. */ | |
c203e8a7 | 117 | register_table_type *registered; /* Hashtable of vtable pointers for which |
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118 | we have generated a _VLTRegisterPair |
119 | call with this vtable map variable. */ | |
120 | bool is_used; /* Boolean indicating if we used this vtable map | |
121 | variable in a call to __VLTVerifyVtablePointer. */ | |
122 | }; | |
123 | ||
124 | /* Controls debugging for vtable verification. */ | |
125 | extern bool vtv_debug; | |
126 | ||
127 | /* The global vector of vtbl_map_nodes. */ | |
128 | extern vec<struct vtbl_map_node *> vtbl_map_nodes_vec; | |
129 | ||
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130 | /* The global vectors for mangled class names for anonymous classes. */ |
131 | extern GTY(()) vec<tree, va_gc> *vtbl_mangled_name_types; | |
132 | extern GTY(()) vec<tree, va_gc> *vtbl_mangled_name_ids; | |
133 | ||
134 | extern void vtbl_register_mangled_name (tree, tree); | |
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135 | extern struct vtbl_map_node *vtbl_map_get_node (tree); |
136 | extern struct vtbl_map_node *find_or_create_vtbl_map_node (tree); | |
137 | extern void vtbl_map_node_class_insert (struct vtbl_map_node *, unsigned); | |
138 | extern bool vtbl_map_node_registration_find (struct vtbl_map_node *, | |
139 | tree, unsigned); | |
140 | extern bool vtbl_map_node_registration_insert (struct vtbl_map_node *, | |
141 | tree, unsigned); | |
142 | ||
143 | #endif /* VTABLE_VERIFY_H */ |