| /* Copyright (C) 2013-2017 Free Software Foundation, Inc. |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it under |
| the terms of the GNU General Public License as published by the Free |
| Software Foundation; either version 3, or (at your option) any later |
| version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* Virtual Table Pointer Security. */ |
| |
| #ifndef VTABLE_VERIFY_H |
| #define VTABLE_VERIFY_H |
| |
| #include "sbitmap.h" |
| |
| /* The function decl used to create calls to __VLTVtableVerify. It must |
| be global because it needs to be initialized in the C++ front end, but |
| used in the middle end (in the vtable verification pass). */ |
| |
| extern tree verify_vtbl_ptr_fndecl; |
| |
| /* Global variable keeping track of how many vtable map variables we |
| have created. */ |
| extern unsigned num_vtable_map_nodes; |
| |
| /* Keep track of how many virtual calls we are actually verifying. */ |
| extern int total_num_virtual_calls; |
| extern int total_num_verified_vcalls; |
| |
| /* Each vtable map variable corresponds to a virtual class. Each |
| vtable map variable has a hash table associated with it, that keeps |
| track of the vtable pointers for which we have generated a call to |
| __VLTRegisterPair (with the current vtable map variable). This is |
| the hash table node that is used for each entry in this hash table |
| of vtable pointers. |
| |
| Sometimes there are multiple valid vtable pointer entries that use |
| the same vtable pointer decl with different offsets. Therefore, |
| for each vtable pointer in the hash table, there is also an array |
| of offsets used with that vtable. */ |
| |
| struct vtable_registration |
| { |
| tree vtable_decl; /* The var decl of the vtable. */ |
| vec<unsigned> offsets; /* The offsets array. */ |
| }; |
| |
| struct registration_hasher : nofree_ptr_hash <struct vtable_registration> |
| { |
| static inline hashval_t hash (const vtable_registration *); |
| static inline bool equal (const vtable_registration *, |
| const vtable_registration *); |
| }; |
| |
| typedef hash_table<registration_hasher> register_table_type; |
| typedef register_table_type::iterator registration_iterator_type; |
| |
| /* This struct is used to represent the class hierarchy information |
| that we need. Each vtable map variable has an associated class |
| hierarchy node (struct vtv_graph_node). Note: In this struct, |
| 'children' means immediate descendants in the class hierarchy; |
| 'descendant' means any descendant however many levels deep. */ |
| |
| struct vtv_graph_node { |
| tree class_type; /* The record_type of the class. */ |
| unsigned class_uid; /* A unique, monotonically |
| ascending id for class node. |
| Each vtable map node also has |
| an id. The class uid is the |
| same as the vtable map node id |
| for nodes corresponding to the |
| same class. */ |
| unsigned num_processed_children; /* # of children for whom we have |
| computed the class hierarchy |
| transitive closure. */ |
| vec<struct vtv_graph_node *> parents; /* Vector of parents in the graph. */ |
| vec<struct vtv_graph_node *> children; /* Vector of children in the graph.*/ |
| sbitmap descendants; /* Bitmap representing all this node's |
| descendants in the graph. */ |
| }; |
| |
| /* This is the node used for our hashtable of vtable map variable |
| information. When we create a vtable map variable (var decl) we |
| put it into one of these nodes; create a corresponding |
| vtv_graph_node for our class hierarchy info and store that in this |
| node; generate a unique (monotonically ascending) id for both the |
| vtbl_map_node and the vtv_graph_node; and insert the node into two |
| data structures (to make it easy to find in several different |
| ways): 1). A hash table ("vtbl_map_hash" in vtable-verify.c). |
| This gives us an easy way to check to see if we already have a node |
| for the vtable map variable or not; and 2). An array (vector) of |
| vtbl_map_nodes, where the array index corresponds to the unique id |
| of the vtbl_map_node, which gives us an easy way to use bitmaps to |
| represent and find the vtable map nodes. */ |
| |
| struct vtbl_map_node { |
| tree vtbl_map_decl; /* The var decl for the vtable map |
| variable. */ |
| tree class_name; /* The DECL_ASSEMBLER_NAME of the |
| class. */ |
| struct vtv_graph_node *class_info; /* Our class hierarchy info for the |
| class. */ |
| unsigned uid; /* The unique id for the vtable map |
| variable. */ |
| struct vtbl_map_node *next, *prev; /* Pointers for the linked list |
| structure. */ |
| register_table_type *registered; /* Hashtable of vtable pointers for which |
| we have generated a _VLTRegisterPair |
| call with this vtable map variable. */ |
| bool is_used; /* Boolean indicating if we used this vtable map |
| variable in a call to __VLTVerifyVtablePointer. */ |
| }; |
| |
| /* Controls debugging for vtable verification. */ |
| extern bool vtv_debug; |
| |
| /* The global vector of vtbl_map_nodes. */ |
| extern vec<struct vtbl_map_node *> vtbl_map_nodes_vec; |
| |
| /* The global vectors for mangled class names for anonymous classes. */ |
| extern GTY(()) vec<tree, va_gc> *vtbl_mangled_name_types; |
| extern GTY(()) vec<tree, va_gc> *vtbl_mangled_name_ids; |
| |
| extern void vtbl_register_mangled_name (tree, tree); |
| extern struct vtbl_map_node *vtbl_map_get_node (tree); |
| extern struct vtbl_map_node *find_or_create_vtbl_map_node (tree); |
| extern void vtbl_map_node_class_insert (struct vtbl_map_node *, unsigned); |
| extern bool vtbl_map_node_registration_find (struct vtbl_map_node *, |
| tree, unsigned); |
| extern bool vtbl_map_node_registration_insert (struct vtbl_map_node *, |
| tree, unsigned); |
| |
| #endif /* VTABLE_VERIFY_H */ |