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23a5b65a | 1 | /* Copyright (C) 2012-2014 Free Software Foundation, Inc. |
2077db1b CT |
2 | |
3 | This file is part of GCC. | |
4 | ||
5 | GCC is free software; you can redistribute it and/or modify it | |
6 | under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 3, or (at your option) | |
8 | any later version. | |
9 | ||
10 | GCC is distributed in the hope that it will be useful, but | |
11 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | General Public License 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 Pass - Detect corruption of vtable pointers | |
20 | before using them for virtual method dispatches. */ | |
21 | ||
22 | /* This file is part of the vtable security feature implementation. | |
23 | The vtable security feature is designed to detect when a virtual | |
24 | call is about to be made through an invalid vtable pointer | |
25 | (possibly due to data corruption or malicious attacks). The | |
26 | compiler finds every virtual call, and inserts a verification call | |
27 | before the virtual call. The verification call takes the actual | |
28 | vtable pointer value in the object through which the virtual call | |
29 | is being made, and compares the vtable pointer against a set of all | |
30 | valid vtable pointers that the object could contain (this set is | |
31 | based on the declared type of the object). If the pointer is in | |
32 | the valid set, execution is allowed to continue; otherwise the | |
33 | program is halted. | |
34 | ||
35 | There are several pieces needed in order to make this work: 1. For | |
36 | every virtual class in the program (i.e. a class that contains | |
37 | virtual methods), we need to build the set of all possible valid | |
38 | vtables that an object of that class could point to. This includes | |
39 | vtables for any class(es) that inherit from the class under | |
40 | consideration. 2. For every such data set we build up, we need a | |
41 | way to find and reference the data set. This is complicated by the | |
42 | fact that the real vtable addresses are not known until runtime, | |
43 | when the program is loaded into memory, but we need to reference the | |
44 | sets at compile time when we are inserting verification calls into | |
45 | the program. 3. We need to find every virtual call in the program, | |
46 | and insert the verification call (with the appropriate arguments) | |
47 | before the virtual call. 4. We need some runtime library pieces: | |
48 | the code to build up the data sets at runtime; the code to actually | |
49 | perform the verification using the data sets; and some code to set | |
50 | protections on the data sets, so they themselves do not become | |
51 | hacker targets. | |
52 | ||
53 | To find and reference the set of valid vtable pointers for any given | |
54 | virtual class, we create a special global varible for each virtual | |
55 | class. We refer to this as the "vtable map variable" for that | |
56 | class. The vtable map variable has the type "void *", and is | |
57 | initialized by the compiler to NULL. At runtime when the set of | |
58 | valid vtable pointers for a virtual class, e.g. class Foo, is built, | |
59 | the vtable map variable for class Foo is made to point to the set. | |
60 | During compile time, when the compiler is inserting verification | |
61 | calls into the program, it passes the vtable map variable for the | |
62 | appropriate class to the verification call, so that at runtime the | |
63 | verification call can find the appropriate data set. | |
64 | ||
65 | The actual set of valid vtable pointers for a virtual class, | |
66 | e.g. class Foo, cannot be built until runtime, when the vtables get | |
67 | loaded into memory and their addresses are known. But the knowledge | |
68 | about which vtables belong in which class' hierarchy is only known | |
69 | at compile time. Therefore at compile time we collect class | |
70 | hierarchy and vtable information about every virtual class, and we | |
71 | generate calls to build up the data sets at runtime. To build the | |
72 | data sets, we call one of the functions we add to the runtime | |
73 | library, __VLTRegisterPair. __VLTRegisterPair takes two arguments, | |
74 | a vtable map variable and the address of a vtable. If the vtable | |
75 | map variable is currently NULL, it creates a new data set (hash | |
76 | table), makes the vtable map variable point to the new data set, and | |
77 | inserts the vtable address into the data set. If the vtable map | |
78 | variable is not NULL, it just inserts the vtable address into the | |
79 | data set. In order to make sure that our data sets are built before | |
80 | any verification calls happen, we create a special constructor | |
81 | initialization function for each compilation unit, give it a very | |
82 | high initialization priority, and insert all of our calls to | |
83 | __VLTRegisterPair into our special constructor initialization | |
84 | function. | |
85 | ||
86 | The vtable verification feature is controlled by the flag | |
87 | '-fvtable-verify='. There are three flavors of this: | |
88 | '-fvtable-verify=std', '-fvtable-verify=preinit', and | |
89 | '-fvtable-verify=none'. If the option '-fvtable-verfy=preinit' is | |
90 | used, then our constructor initialization function gets put into the | |
91 | preinit array. This is necessary if there are data sets that need | |
92 | to be built very early in execution. If the constructor | |
93 | initialization function gets put into the preinit array, the we also | |
94 | add calls to __VLTChangePermission at the beginning and end of the | |
95 | function. The call at the beginning sets the permissions on the | |
96 | data sets and vtable map variables to read/write, and the one at the | |
97 | end makes them read-only. If the '-fvtable-verify=std' option is | |
98 | used, the constructor initialization functions are executed at their | |
99 | normal time, and the __VLTChangePermission calls are handled | |
100 | differently (see the comments in libstdc++-v3/libsupc++/vtv_rts.cc). | |
101 | The option '-fvtable-verify=none' turns off vtable verification. | |
102 | ||
103 | This file contains code to find and record the class hierarchies for | |
104 | the virtual classes in a program, and all the vtables associated | |
105 | with each such class; to generate the vtable map variables; and to | |
106 | generate the constructor initialization function (with the calls to | |
107 | __VLTRegisterPair, and __VLTChangePermission). The main data | |
108 | structures used for collecting the class hierarchy data and | |
109 | building/maintaining the vtable map variable data are defined in | |
110 | gcc/vtable-verify.h, because they are used both here and in | |
111 | gcc/vtable-verify.c. */ | |
112 | ||
113 | #include "config.h" | |
114 | #include "system.h" | |
115 | #include "coretypes.h" | |
2077db1b | 116 | #include "cp-tree.h" |
2077db1b | 117 | #include "output.h" |
2077db1b | 118 | #include "cgraph.h" |
2077db1b CT |
119 | #include "tree-iterator.h" |
120 | #include "vtable-verify.h" | |
45b0be94 | 121 | #include "gimplify.h" |
d8a2d370 DN |
122 | #include "stringpool.h" |
123 | #include "stor-layout.h" | |
2077db1b CT |
124 | |
125 | static int num_calls_to_regset = 0; | |
126 | static int num_calls_to_regpair = 0; | |
127 | static int current_set_size; | |
128 | ||
129 | /* Mark these specially since they need to be stored in precompiled | |
130 | header IR. */ | |
131 | static GTY (()) vec<tree, va_gc> *vlt_saved_class_info; | |
132 | static GTY (()) tree vlt_register_pairs_fndecl = NULL_TREE; | |
133 | static GTY (()) tree vlt_register_set_fndecl = NULL_TREE; | |
134 | ||
135 | struct work_node { | |
136 | struct vtv_graph_node *node; | |
137 | struct work_node *next; | |
138 | }; | |
139 | ||
140 | struct vtbl_map_node *vtable_find_or_create_map_decl (tree); | |
141 | ||
142 | /* As part of vtable verification the compiler generates and inserts | |
143 | calls to __VLTVerifyVtablePointer, which is in libstdc++. This | |
144 | function builds and initializes the function decl that is used | |
145 | in generating those function calls. | |
146 | ||
147 | In addition to __VLTVerifyVtablePointer there is also | |
148 | __VLTVerifyVtablePointerDebug which can be used in place of | |
149 | __VLTVerifyVtablePointer, and which takes extra parameters and | |
150 | outputs extra information, to help debug problems. The debug | |
151 | version of this function is generated and used if flag_vtv_debug is | |
152 | true. | |
153 | ||
154 | The signatures for these functions are: | |
155 | ||
156 | void * __VLTVerifyVtablePointer (void **, void*); | |
157 | void * __VLTVerifyVtablePointerDebug (void**, void *, char *, char *); | |
158 | */ | |
159 | ||
160 | void | |
161 | vtv_build_vtable_verify_fndecl (void) | |
162 | { | |
163 | tree func_type = NULL_TREE; | |
164 | ||
165 | if (verify_vtbl_ptr_fndecl != NULL_TREE | |
166 | && TREE_CODE (verify_vtbl_ptr_fndecl) != ERROR_MARK) | |
167 | return; | |
168 | ||
169 | if (flag_vtv_debug) | |
170 | { | |
171 | func_type = build_function_type_list (const_ptr_type_node, | |
172 | build_pointer_type (ptr_type_node), | |
173 | const_ptr_type_node, | |
174 | const_string_type_node, | |
175 | const_string_type_node, | |
176 | NULL_TREE); | |
177 | verify_vtbl_ptr_fndecl = | |
178 | build_lang_decl (FUNCTION_DECL, | |
179 | get_identifier ("__VLTVerifyVtablePointerDebug"), | |
180 | func_type); | |
181 | } | |
182 | else | |
183 | { | |
184 | func_type = build_function_type_list (const_ptr_type_node, | |
185 | build_pointer_type (ptr_type_node), | |
186 | const_ptr_type_node, | |
187 | NULL_TREE); | |
188 | verify_vtbl_ptr_fndecl = | |
189 | build_lang_decl (FUNCTION_DECL, | |
190 | get_identifier ("__VLTVerifyVtablePointer"), | |
191 | func_type); | |
192 | } | |
193 | ||
194 | TREE_NOTHROW (verify_vtbl_ptr_fndecl) = 1; | |
195 | DECL_ATTRIBUTES (verify_vtbl_ptr_fndecl) | |
196 | = tree_cons (get_identifier ("leaf"), NULL, | |
197 | DECL_ATTRIBUTES (verify_vtbl_ptr_fndecl)); | |
198 | DECL_PURE_P (verify_vtbl_ptr_fndecl) = 1; | |
199 | TREE_PUBLIC (verify_vtbl_ptr_fndecl) = 1; | |
200 | DECL_PRESERVE_P (verify_vtbl_ptr_fndecl) = 1; | |
201 | } | |
202 | ||
203 | /* As part of vtable verification the compiler generates and inserts | |
204 | calls to __VLTRegisterSet and __VLTRegisterPair, which are in | |
205 | libsupc++. This function builds and initializes the function decls | |
206 | that are used in generating those function calls. | |
207 | ||
208 | The signatures for these functions are: | |
209 | ||
210 | void __VLTRegisterSetDebug (void **, const void *, std::size_t, | |
211 | size_t, void **); | |
212 | ||
213 | void __VLTRegisterSet (void **, const void *, std::size_t, | |
214 | size_t, void **); | |
215 | ||
216 | void __VLTRegisterPairDebug (void **, const void *, size_t, | |
217 | const void *, const char *, const char *); | |
218 | ||
219 | void __VLTRegisterPair (void **, const void *, size_t, const void *); | |
220 | */ | |
221 | ||
222 | static void | |
223 | init_functions (void) | |
224 | { | |
225 | tree register_set_type; | |
226 | tree register_pairs_type; | |
227 | ||
228 | if (vlt_register_set_fndecl != NULL_TREE) | |
229 | return; | |
230 | ||
231 | gcc_assert (vlt_register_pairs_fndecl == NULL_TREE); | |
232 | gcc_assert (vlt_register_set_fndecl == NULL_TREE); | |
233 | ||
234 | /* Build function decl for __VLTRegisterSet*. */ | |
235 | ||
236 | register_set_type = build_function_type_list | |
237 | (void_type_node, | |
238 | build_pointer_type (ptr_type_node), | |
239 | const_ptr_type_node, | |
240 | size_type_node, | |
241 | size_type_node, | |
242 | build_pointer_type (ptr_type_node), | |
243 | NULL_TREE); | |
244 | ||
245 | if (flag_vtv_debug) | |
246 | vlt_register_set_fndecl = build_lang_decl | |
247 | (FUNCTION_DECL, | |
248 | get_identifier ("__VLTRegisterSetDebug"), | |
249 | register_set_type); | |
250 | else | |
251 | vlt_register_set_fndecl = build_lang_decl | |
252 | (FUNCTION_DECL, | |
253 | get_identifier ("__VLTRegisterSet"), | |
254 | register_set_type); | |
255 | ||
256 | ||
257 | TREE_NOTHROW (vlt_register_set_fndecl) = 1; | |
258 | DECL_ATTRIBUTES (vlt_register_set_fndecl) = | |
259 | tree_cons (get_identifier ("leaf"), NULL, | |
260 | DECL_ATTRIBUTES (vlt_register_set_fndecl)); | |
31226750 | 261 | DECL_EXTERNAL(vlt_register_set_fndecl) = 1; |
2077db1b CT |
262 | TREE_PUBLIC (vlt_register_set_fndecl) = 1; |
263 | DECL_PRESERVE_P (vlt_register_set_fndecl) = 1; | |
264 | SET_DECL_LANGUAGE (vlt_register_set_fndecl, lang_cplusplus); | |
265 | ||
266 | /* Build function decl for __VLTRegisterPair*. */ | |
267 | ||
268 | if (flag_vtv_debug) | |
269 | { | |
270 | register_pairs_type = build_function_type_list (void_type_node, | |
271 | build_pointer_type | |
272 | (ptr_type_node), | |
273 | const_ptr_type_node, | |
274 | size_type_node, | |
275 | const_ptr_type_node, | |
276 | const_string_type_node, | |
277 | const_string_type_node, | |
278 | NULL_TREE); | |
279 | ||
280 | vlt_register_pairs_fndecl = build_lang_decl | |
281 | (FUNCTION_DECL, | |
282 | get_identifier ("__VLTRegisterPairDebug"), | |
283 | register_pairs_type); | |
284 | } | |
285 | else | |
286 | { | |
287 | register_pairs_type = build_function_type_list (void_type_node, | |
288 | build_pointer_type | |
289 | (ptr_type_node), | |
290 | const_ptr_type_node, | |
291 | size_type_node, | |
292 | const_ptr_type_node, | |
293 | NULL_TREE); | |
294 | ||
295 | vlt_register_pairs_fndecl = build_lang_decl | |
296 | (FUNCTION_DECL, | |
297 | get_identifier ("__VLTRegisterPair"), | |
298 | register_pairs_type); | |
299 | } | |
300 | ||
301 | TREE_NOTHROW (vlt_register_pairs_fndecl) = 1; | |
302 | DECL_ATTRIBUTES (vlt_register_pairs_fndecl) = | |
303 | tree_cons (get_identifier ("leaf"), NULL, | |
304 | DECL_ATTRIBUTES (vlt_register_pairs_fndecl)); | |
31226750 | 305 | DECL_EXTERNAL(vlt_register_pairs_fndecl) = 1; |
2077db1b CT |
306 | TREE_PUBLIC (vlt_register_pairs_fndecl) = 1; |
307 | DECL_PRESERVE_P (vlt_register_pairs_fndecl) = 1; | |
308 | SET_DECL_LANGUAGE (vlt_register_pairs_fndecl, lang_cplusplus); | |
309 | ||
310 | } | |
311 | ||
312 | /* This is a helper function for | |
313 | vtv_compute_class_hierarchy_transitive_closure. It adds a | |
314 | vtv_graph_node to the WORKLIST, which is a linked list of | |
315 | seen-but-not-yet-processed nodes. INSERTED is a bitmap, one bit | |
316 | per node, to help make sure that we don't insert a node into the | |
317 | worklist more than once. Each node represents a class somewhere in | |
318 | our class hierarchy information. Every node in the graph gets added | |
319 | to the worklist exactly once and removed from the worklist exactly | |
320 | once (when all of its children have been processed). */ | |
321 | ||
322 | static void | |
323 | add_to_worklist (struct work_node **worklist, struct vtv_graph_node *node, | |
324 | sbitmap inserted) | |
325 | { | |
326 | struct work_node *new_work_node; | |
327 | ||
328 | if (bitmap_bit_p (inserted, node->class_uid)) | |
329 | return; | |
330 | ||
331 | new_work_node = XNEW (struct work_node); | |
332 | new_work_node->next = *worklist; | |
333 | new_work_node->node = node; | |
334 | *worklist = new_work_node; | |
335 | ||
336 | bitmap_set_bit (inserted, node->class_uid); | |
337 | } | |
338 | ||
339 | /* This is a helper function for | |
340 | vtv_compute_class_hierarchy_transitive_closure. It goes through | |
341 | the WORKLIST of class hierarchy nodes looking for a "leaf" node, | |
342 | i.e. a node whose children in the hierarchy have all been | |
343 | processed. When it finds the next leaf node, it removes it from | |
344 | the linked list (WORKLIST) and returns the node. */ | |
345 | ||
346 | static struct vtv_graph_node * | |
347 | find_and_remove_next_leaf_node (struct work_node **worklist) | |
348 | { | |
349 | struct work_node *prev, *cur; | |
350 | struct vtv_graph_node *ret_val = NULL; | |
351 | ||
352 | for (prev = NULL, cur = *worklist; cur; prev = cur, cur = cur->next) | |
353 | { | |
354 | if ((cur->node->children).length() == cur->node->num_processed_children) | |
355 | { | |
356 | if (prev == NULL) | |
357 | (*worklist) = cur->next; | |
358 | else | |
359 | prev->next = cur->next; | |
360 | ||
361 | cur->next = NULL; | |
362 | ret_val = cur->node; | |
363 | free (cur); | |
364 | return ret_val; | |
365 | } | |
366 | } | |
367 | ||
368 | return NULL; | |
369 | } | |
370 | ||
371 | /* In our class hierarchy graph, each class node contains a bitmap, | |
372 | with one bit for each class in the hierarchy. The bits are set for | |
373 | classes that are descendants in the graph of the current node. | |
374 | Initially the descendants bitmap is only set for immediate | |
375 | descendants. This function traverses the class hierarchy graph, | |
376 | bottom up, filling in the transitive closures for the descendants | |
377 | as we rise up the graph. */ | |
378 | ||
379 | void | |
380 | vtv_compute_class_hierarchy_transitive_closure (void) | |
381 | { | |
382 | struct work_node *worklist = NULL; | |
383 | sbitmap inserted = sbitmap_alloc (num_vtable_map_nodes); | |
384 | unsigned i; | |
385 | unsigned j; | |
386 | ||
387 | /* Note: Every node in the graph gets added to the worklist exactly | |
388 | once and removed from the worklist exactly once (when all of its | |
389 | children have been processed). Each node's children edges are | |
390 | followed exactly once, and each node's parent edges are followed | |
391 | exactly once. So this algorithm is roughly O(V + 2E), i.e. | |
392 | O(E + V). */ | |
393 | ||
394 | /* Set-up: */ | |
395 | /* Find all the "leaf" nodes in the graph, and add them to the worklist. */ | |
396 | bitmap_clear (inserted); | |
397 | for (j = 0; j < num_vtable_map_nodes; ++j) | |
398 | { | |
399 | struct vtbl_map_node *cur = vtbl_map_nodes_vec[j]; | |
400 | if (cur->class_info | |
401 | && ((cur->class_info->children).length() == 0) | |
402 | && ! (bitmap_bit_p (inserted, cur->class_info->class_uid))) | |
403 | add_to_worklist (&worklist, cur->class_info, inserted); | |
404 | } | |
405 | ||
406 | /* Main work: pull next leaf node off work list, process it, add its | |
407 | parents to the worklist, where a 'leaf' node is one that has no | |
408 | children, or all of its children have been processed. */ | |
409 | while (worklist) | |
410 | { | |
411 | struct vtv_graph_node *temp_node = | |
412 | find_and_remove_next_leaf_node (&worklist); | |
413 | ||
414 | gcc_assert (temp_node != NULL); | |
415 | temp_node->descendants = sbitmap_alloc (num_vtable_map_nodes); | |
416 | bitmap_clear (temp_node->descendants); | |
417 | bitmap_set_bit (temp_node->descendants, temp_node->class_uid); | |
418 | for (i = 0; i < (temp_node->children).length(); ++i) | |
419 | bitmap_ior (temp_node->descendants, temp_node->descendants, | |
420 | temp_node->children[i]->descendants); | |
421 | for (i = 0; i < (temp_node->parents).length(); ++i) | |
422 | { | |
423 | temp_node->parents[i]->num_processed_children = | |
424 | temp_node->parents[i]->num_processed_children + 1; | |
425 | if (!bitmap_bit_p (inserted, temp_node->parents[i]->class_uid)) | |
426 | add_to_worklist (&worklist, temp_node->parents[i], inserted); | |
427 | } | |
428 | } | |
429 | } | |
430 | ||
431 | /* Keep track of which pairs we have already created __VLTRegisterPair | |
432 | calls for, to prevent creating duplicate calls within the same | |
433 | compilation unit. VTABLE_DECL is the var decl for the vtable of | |
434 | the (descendant) class that we are adding to our class hierarchy | |
435 | data. VPTR_ADDRESS is an expression for calculating the correct | |
436 | offset into the vtable (VTABLE_DECL). It is the actual vtable | |
437 | pointer address that will be stored in our list of valid vtable | |
438 | pointers for BASE_CLASS. BASE_CLASS is the record_type node for | |
439 | the base class to whose hiearchy we want to add | |
440 | VPTR_ADDRESS. (VTABLE_DECL should be the vtable for BASE_CLASS or | |
441 | one of BASE_CLASS' descendents. */ | |
442 | ||
443 | static bool | |
444 | check_and_record_registered_pairs (tree vtable_decl, tree vptr_address, | |
445 | tree base_class) | |
446 | { | |
447 | unsigned offset; | |
448 | struct vtbl_map_node *base_vtable_map_node; | |
449 | bool inserted_something = false; | |
450 | ||
451 | ||
452 | if (TREE_CODE (vptr_address) == ADDR_EXPR | |
453 | && TREE_CODE (TREE_OPERAND (vptr_address, 0)) == MEM_REF) | |
454 | vptr_address = TREE_OPERAND (vptr_address, 0); | |
455 | ||
456 | if (TREE_OPERAND_LENGTH (vptr_address) > 1) | |
457 | offset = TREE_INT_CST_LOW (TREE_OPERAND (vptr_address, 1)); | |
458 | else | |
459 | offset = 0; | |
460 | ||
461 | base_vtable_map_node = vtbl_map_get_node (TYPE_MAIN_VARIANT (base_class)); | |
462 | ||
463 | inserted_something = vtbl_map_node_registration_insert | |
464 | (base_vtable_map_node, | |
465 | vtable_decl, | |
466 | offset); | |
467 | return !inserted_something; | |
468 | } | |
469 | ||
470 | /* Given an IDENTIFIER_NODE, build and return a string literal based on it. */ | |
471 | ||
472 | static tree | |
473 | build_string_from_id (tree identifier) | |
474 | { | |
475 | int len; | |
476 | ||
477 | gcc_assert (TREE_CODE (identifier) == IDENTIFIER_NODE); | |
478 | ||
479 | len = IDENTIFIER_LENGTH (identifier); | |
480 | return build_string_literal (len + 1, IDENTIFIER_POINTER (identifier)); | |
481 | } | |
482 | ||
483 | /* A class may contain secondary vtables in it, for various reasons. | |
484 | This function goes through the decl chain of a class record looking | |
485 | for any fields that point to secondary vtables, and adding calls to | |
486 | __VLTRegisterPair for the secondary vtable pointers. | |
487 | ||
488 | BASE_CLASS_DECL_ARG is an expression for the address of the vtable | |
489 | map variable for the BASE_CLASS (whose hierarchy we are currently | |
490 | updating). BASE_CLASS is the record_type node for the base class. | |
491 | RECORD_TYPE is the record_type node for the descendant class that | |
492 | we are possibly adding to BASE_CLASS's hierarchy. BODY is the | |
493 | function body for the constructor init function to which we are | |
494 | adding our calls to __VLTRegisterPair. */ | |
495 | ||
496 | static void | |
497 | register_construction_vtables (tree base_class, tree record_type, | |
b208ba40 | 498 | vec<tree> *vtable_ptr_array) |
2077db1b CT |
499 | { |
500 | tree vtbl_var_decl; | |
501 | ||
502 | if (TREE_CODE (record_type) != RECORD_TYPE) | |
503 | return; | |
504 | ||
505 | vtbl_var_decl = CLASSTYPE_VTABLES (record_type); | |
506 | ||
507 | if (CLASSTYPE_VBASECLASSES (record_type)) | |
508 | { | |
509 | tree vtt_decl; | |
510 | bool already_registered = false; | |
511 | tree val_vtbl_decl = NULL_TREE; | |
512 | ||
513 | vtt_decl = DECL_CHAIN (vtbl_var_decl); | |
514 | ||
515 | /* Check to see if we have found a VTT. Add its data if appropriate. */ | |
516 | if (vtt_decl) | |
517 | { | |
518 | tree values = DECL_INITIAL (vtt_decl); | |
519 | if (TREE_ASM_WRITTEN (vtt_decl) | |
520 | && values != NULL_TREE | |
521 | && TREE_CODE (values) == CONSTRUCTOR | |
522 | && TREE_CODE (TREE_TYPE (values)) == ARRAY_TYPE) | |
523 | { | |
524 | unsigned HOST_WIDE_INT cnt; | |
525 | constructor_elt *ce; | |
526 | ||
527 | /* Loop through the initialization values for this | |
528 | vtable to get all the correct vtable pointer | |
529 | addresses that we need to add to our set of valid | |
530 | vtable pointers for the current base class. This may | |
531 | result in adding more than just the element assigned | |
532 | to the primary vptr of the class, so we may end up | |
533 | with more vtable pointers than are strictly | |
534 | necessary. */ | |
535 | ||
536 | for (cnt = 0; | |
537 | vec_safe_iterate (CONSTRUCTOR_ELTS (values), | |
538 | cnt, &ce); | |
539 | cnt++) | |
540 | { | |
541 | tree value = ce->value; | |
542 | ||
543 | /* Search for the ADDR_EXPR operand within the value. */ | |
544 | ||
545 | while (value | |
546 | && TREE_OPERAND (value, 0) | |
547 | && TREE_CODE (TREE_OPERAND (value, 0)) == ADDR_EXPR) | |
548 | value = TREE_OPERAND (value, 0); | |
549 | ||
550 | /* The VAR_DECL for the vtable should be the first | |
551 | argument of the ADDR_EXPR, which is the first | |
552 | argument of value.*/ | |
553 | ||
554 | if (TREE_OPERAND (value, 0)) | |
555 | val_vtbl_decl = TREE_OPERAND (value, 0); | |
556 | ||
557 | while (TREE_CODE (val_vtbl_decl) != VAR_DECL | |
558 | && TREE_OPERAND (val_vtbl_decl, 0)) | |
559 | val_vtbl_decl = TREE_OPERAND (val_vtbl_decl, 0); | |
560 | ||
561 | gcc_assert (TREE_CODE (val_vtbl_decl) == VAR_DECL); | |
562 | ||
563 | /* Check to see if we already have this vtable pointer in | |
564 | our valid set for this base class. */ | |
565 | ||
566 | already_registered = check_and_record_registered_pairs | |
567 | (val_vtbl_decl, | |
568 | value, | |
569 | base_class); | |
570 | ||
571 | if (already_registered) | |
572 | continue; | |
573 | ||
574 | /* Add this vtable pointer to our set of valid | |
575 | pointers for the base class. */ | |
576 | ||
b208ba40 | 577 | vtable_ptr_array->safe_push (value); |
2077db1b CT |
578 | current_set_size++; |
579 | } | |
580 | } | |
581 | } | |
582 | } | |
583 | } | |
584 | ||
585 | /* This function iterates through all the vtables it can find from the | |
586 | BINFO of a class, to make sure we have found ALL of the vtables | |
587 | that an object of that class could point to. Generate calls to | |
588 | __VLTRegisterPair for those vtable pointers that we find. | |
589 | ||
590 | BINFO is the tree_binfo node for the BASE_CLASS. BODY is the | |
591 | function body for the constructor init function to which we are | |
592 | adding calls to __VLTRegisterPair. ARG1 is an expression for the | |
593 | address of the vtable map variable (for the BASE_CLASS), that will | |
594 | point to the updated data set. BASE_CLASS is the record_type node | |
595 | for the base class whose set of valid vtable pointers we are | |
596 | updating. STR1 and STR2 are all debugging information, to be passed | |
597 | as parameters to __VLTRegisterPairDebug. STR1 represents the name | |
598 | of the vtable map variable to be updated by the call. Similarly, | |
599 | STR2 represents the name of the class whose vtable pointer is being | |
600 | added to the hierarchy. */ | |
601 | ||
602 | static void | |
603 | register_other_binfo_vtables (tree binfo, tree base_class, | |
b208ba40 | 604 | vec<tree> *vtable_ptr_array) |
2077db1b CT |
605 | { |
606 | unsigned ix; | |
607 | tree base_binfo; | |
608 | tree vtable_decl; | |
609 | bool already_registered; | |
610 | ||
611 | if (binfo == NULL_TREE) | |
612 | return; | |
613 | ||
614 | for (ix = 0; BINFO_BASE_ITERATE (binfo, ix, base_binfo); ix++) | |
615 | { | |
616 | if ((!BINFO_PRIMARY_P (base_binfo) | |
617 | || BINFO_VIRTUAL_P (base_binfo)) | |
618 | && (vtable_decl = get_vtbl_decl_for_binfo (base_binfo))) | |
619 | { | |
620 | tree vtable_address = build_vtbl_address (base_binfo); | |
621 | ||
622 | already_registered = check_and_record_registered_pairs | |
623 | (vtable_decl, | |
624 | vtable_address, | |
625 | base_class); | |
626 | if (!already_registered) | |
627 | { | |
b208ba40 | 628 | vtable_ptr_array->safe_push (vtable_address); |
2077db1b CT |
629 | current_set_size++; |
630 | } | |
631 | } | |
632 | ||
b208ba40 | 633 | register_other_binfo_vtables (base_binfo, base_class, vtable_ptr_array); |
2077db1b CT |
634 | } |
635 | } | |
636 | ||
637 | /* The set of valid vtable pointers for any given class are stored in | |
638 | a hash table. For reasons of efficiency, that hash table size is | |
639 | always a power of two. In order to try to prevent re-sizing the | |
640 | hash tables very often, we pass __VLTRegisterPair an initial guess | |
641 | as to the number of entries the hashtable will eventually need | |
642 | (rounded up to the nearest power of two). This function takes the | |
643 | class information we have collected for a particular class, | |
644 | CLASS_NODE, and calculates the hash table size guess. */ | |
645 | ||
646 | static int | |
647 | guess_num_vtable_pointers (struct vtv_graph_node *class_node) | |
648 | { | |
649 | tree vtbl; | |
650 | int total_num_vtbls = 0; | |
651 | int num_vtbls_power_of_two = 1; | |
652 | unsigned i; | |
653 | ||
654 | for (i = 0; i < num_vtable_map_nodes; ++i) | |
655 | if (bitmap_bit_p (class_node->descendants, i)) | |
656 | { | |
657 | tree class_type = vtbl_map_nodes_vec[i]->class_info->class_type; | |
658 | for (vtbl = CLASSTYPE_VTABLES (class_type); vtbl; | |
659 | vtbl = DECL_CHAIN (vtbl)) | |
660 | { | |
661 | total_num_vtbls++; | |
662 | if (total_num_vtbls > num_vtbls_power_of_two) | |
663 | num_vtbls_power_of_two <<= 1; | |
664 | } | |
665 | } | |
666 | return num_vtbls_power_of_two; | |
667 | } | |
668 | ||
669 | /* A simple hash function on strings */ | |
670 | /* Be careful about changing this routine. The values generated will | |
671 | be stored in the calls to InitSet. So, changing this routine may | |
672 | cause a binary incompatibility. */ | |
673 | ||
674 | static uint32_t | |
675 | vtv_string_hash (const char *in) | |
676 | { | |
677 | const char *s = in; | |
678 | uint32_t h = 0; | |
679 | ||
680 | gcc_assert (in != NULL); | |
681 | for ( ; *s; ++s) | |
682 | h = 5 * h + *s; | |
683 | return h; | |
684 | } | |
685 | ||
686 | static char * | |
687 | get_log_file_name (const char *fname) | |
688 | { | |
689 | const char *tmp_dir = concat (dump_dir_name, NULL); | |
690 | char *full_name; | |
691 | int dir_len; | |
692 | int fname_len; | |
693 | ||
694 | dir_len = strlen (tmp_dir); | |
695 | fname_len = strlen (fname); | |
696 | ||
697 | full_name = XNEWVEC (char, dir_len + fname_len + 1); | |
698 | strcpy (full_name, tmp_dir); | |
699 | strcpy (full_name + dir_len, fname); | |
700 | ||
701 | return full_name; | |
702 | } | |
703 | ||
704 | static void | |
705 | write_out_current_set_data (tree base_class, int set_size) | |
706 | { | |
707 | static int class_data_log_fd = -1; | |
708 | char buffer[1024]; | |
709 | int bytes_written __attribute__ ((unused)); | |
710 | char *file_name = get_log_file_name ("vtv_class_set_sizes.log"); | |
711 | ||
712 | if (class_data_log_fd == -1) | |
713 | class_data_log_fd = open (file_name, | |
714 | O_WRONLY | O_APPEND | O_CREAT, S_IRWXU); | |
715 | ||
716 | if (class_data_log_fd == -1) | |
717 | { | |
b208ba40 CT |
718 | warning_at (UNKNOWN_LOCATION, 0, |
719 | "unable to open log file %<vtv_class_set_sizes.log%>: %m"); | |
2077db1b CT |
720 | return; |
721 | } | |
722 | ||
723 | snprintf (buffer, sizeof (buffer), "%s %d\n", | |
724 | IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (TYPE_NAME (base_class))), | |
725 | set_size); | |
726 | bytes_written = write (class_data_log_fd, buffer, strlen (buffer)); | |
727 | } | |
728 | ||
729 | static tree | |
730 | build_key_buffer_arg (tree base_ptr_var_decl) | |
731 | { | |
732 | const int key_type_fixed_size = 8; | |
733 | uint32_t len1 = IDENTIFIER_LENGTH (DECL_NAME (base_ptr_var_decl)); | |
734 | uint32_t hash_value = vtv_string_hash (IDENTIFIER_POINTER | |
735 | (DECL_NAME (base_ptr_var_decl))); | |
736 | void *key_buffer = xmalloc (len1 + key_type_fixed_size); | |
737 | uint32_t *value_ptr = (uint32_t *) key_buffer; | |
738 | tree ret_value; | |
739 | ||
740 | /* Set the len and hash for the string. */ | |
741 | *value_ptr = len1; | |
742 | value_ptr++; | |
743 | *value_ptr = hash_value; | |
744 | ||
745 | /* Now copy the string representation of the vtbl map name... */ | |
746 | memcpy ((char *) key_buffer + key_type_fixed_size, | |
747 | IDENTIFIER_POINTER (DECL_NAME (base_ptr_var_decl)), | |
748 | len1); | |
749 | ||
750 | /* ... and build a string literal from it. This will make a copy | |
751 | so the key_bufffer is not needed anymore after this. */ | |
752 | ret_value = build_string_literal (len1 + key_type_fixed_size, | |
753 | (char *) key_buffer); | |
754 | free (key_buffer); | |
755 | return ret_value; | |
756 | } | |
757 | ||
758 | static void | |
b208ba40 CT |
759 | insert_call_to_register_set (tree class_name, |
760 | vec<tree> *vtbl_ptr_array, tree body, tree arg1, | |
2077db1b CT |
761 | tree arg2, tree size_hint_arg) |
762 | { | |
763 | tree call_expr; | |
b208ba40 | 764 | int num_args = vtbl_ptr_array->length(); |
2077db1b CT |
765 | char *array_arg_name = ACONCAT (("__vptr_array_", |
766 | IDENTIFIER_POINTER (class_name), NULL)); | |
767 | tree array_arg_type = build_array_type_nelts (build_pointer_type | |
768 | (build_pointer_type | |
769 | (void_type_node)), | |
770 | num_args); | |
771 | tree array_arg = build_decl (UNKNOWN_LOCATION, VAR_DECL, | |
772 | get_identifier (array_arg_name), | |
773 | array_arg_type); | |
774 | int k; | |
775 | ||
776 | vec<constructor_elt, va_gc> *array_elements; | |
777 | vec_alloc (array_elements, num_args); | |
778 | ||
779 | tree initial = NULL_TREE; | |
780 | tree arg3 = NULL_TREE; | |
781 | ||
782 | TREE_PUBLIC (array_arg) = 0; | |
783 | DECL_EXTERNAL (array_arg) = 0; | |
784 | TREE_STATIC (array_arg) = 1; | |
785 | DECL_ARTIFICIAL (array_arg) = 0; | |
786 | TREE_READONLY (array_arg) = 1; | |
787 | DECL_IGNORED_P (array_arg) = 0; | |
788 | DECL_PRESERVE_P (array_arg) = 0; | |
789 | DECL_VISIBILITY (array_arg) = VISIBILITY_HIDDEN; | |
790 | ||
791 | for (k = 0; k < num_args; ++k) | |
792 | { | |
b208ba40 | 793 | CONSTRUCTOR_APPEND_ELT (array_elements, NULL_TREE, (*vtbl_ptr_array)[k]); |
2077db1b CT |
794 | } |
795 | ||
796 | initial = build_constructor (TREE_TYPE (array_arg), array_elements); | |
797 | ||
798 | TREE_CONSTANT (initial) = 1; | |
799 | TREE_STATIC (initial) = 1; | |
800 | DECL_INITIAL (array_arg) = initial; | |
801 | relayout_decl (array_arg); | |
802 | varpool_finalize_decl (array_arg); | |
803 | ||
804 | arg3 = build1 (ADDR_EXPR, TYPE_POINTER_TO (TREE_TYPE (array_arg)), array_arg); | |
805 | ||
806 | TREE_TYPE (arg3) = build_pointer_type (TREE_TYPE (array_arg)); | |
807 | ||
808 | call_expr = build_call_expr (vlt_register_set_fndecl, 5, arg1, | |
809 | arg2, /* set_symbol_key */ | |
810 | size_hint_arg, build_int_cst (size_type_node, | |
811 | num_args), | |
812 | arg3); | |
813 | append_to_statement_list (call_expr, &body); | |
814 | num_calls_to_regset++; | |
815 | } | |
816 | ||
817 | static void | |
b208ba40 | 818 | insert_call_to_register_pair (vec<tree> *vtbl_ptr_array, tree arg1, |
2077db1b CT |
819 | tree arg2, tree size_hint_arg, tree str1, |
820 | tree str2, tree body) | |
821 | { | |
822 | tree call_expr; | |
b208ba40 CT |
823 | int num_args = vtbl_ptr_array->length(); |
824 | tree vtable_address = NULL_TREE; | |
2077db1b CT |
825 | |
826 | if (num_args == 0) | |
827 | vtable_address = build_int_cst (build_pointer_type (void_type_node), 0); | |
b208ba40 CT |
828 | else |
829 | vtable_address = (*vtbl_ptr_array)[0]; | |
2077db1b CT |
830 | |
831 | if (flag_vtv_debug) | |
832 | call_expr = build_call_expr (vlt_register_pairs_fndecl, 6, arg1, arg2, | |
833 | size_hint_arg, vtable_address, str1, str2); | |
834 | else | |
835 | call_expr = build_call_expr (vlt_register_pairs_fndecl, 4, arg1, arg2, | |
836 | size_hint_arg, vtable_address); | |
837 | ||
838 | append_to_statement_list (call_expr, &body); | |
839 | num_calls_to_regpair++; | |
840 | } | |
841 | ||
842 | static void | |
b208ba40 | 843 | output_set_info (tree record_type, vec<tree> vtbl_ptr_array) |
2077db1b CT |
844 | { |
845 | static int vtv_debug_log_fd = -1; | |
846 | char buffer[1024]; | |
847 | int bytes_written __attribute__ ((unused)); | |
b208ba40 | 848 | int array_len = vtbl_ptr_array.length(); |
2077db1b CT |
849 | const char *class_name = |
850 | IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (TYPE_NAME (record_type))); | |
851 | char *file_name = get_log_file_name ("vtv_set_ptr_data.log"); | |
852 | ||
853 | if (vtv_debug_log_fd == -1) | |
854 | vtv_debug_log_fd = open (file_name, | |
855 | O_WRONLY | O_APPEND | O_CREAT, S_IRWXU); | |
856 | if (vtv_debug_log_fd == -1) | |
857 | { | |
b208ba40 CT |
858 | warning_at (UNKNOWN_LOCATION, 0, |
859 | "unable to open log file %<vtv_set_ptr_data.log%>: %m"); | |
2077db1b CT |
860 | return; |
861 | } | |
862 | ||
b208ba40 | 863 | for (int i = 0; i < array_len; ++i) |
2077db1b CT |
864 | { |
865 | const char *vptr_name = "unknown"; | |
866 | int vptr_offset = 0; | |
867 | ||
868 | if (TREE_CODE (vtbl_ptr_array[i]) == POINTER_PLUS_EXPR) | |
869 | { | |
870 | tree arg0 = TREE_OPERAND (vtbl_ptr_array[i], 0); | |
871 | tree arg1 = TREE_OPERAND (vtbl_ptr_array[i], 1); | |
872 | ||
873 | if (TREE_CODE (arg0) == ADDR_EXPR) | |
874 | arg0 = TREE_OPERAND (arg0, 0); | |
875 | ||
876 | if (TREE_CODE (arg0) == VAR_DECL) | |
877 | vptr_name = IDENTIFIER_POINTER (DECL_NAME (arg0)); | |
878 | ||
879 | if (TREE_CODE (arg1) == INTEGER_CST) | |
880 | vptr_offset = TREE_INT_CST_LOW (arg1); | |
881 | } | |
882 | ||
883 | snprintf (buffer, sizeof (buffer), "%s %s %s + %d\n", | |
884 | main_input_filename, class_name, vptr_name, vptr_offset); | |
885 | bytes_written = write (vtv_debug_log_fd, buffer, strlen(buffer)); | |
886 | } | |
887 | ||
888 | } | |
889 | ||
890 | /* This function goes through our internal class hierarchy & vtable | |
891 | pointer data structure and outputs calls to __VLTRegisterPair for | |
892 | every class-vptr pair (for those classes whose vtable would be | |
893 | output in the current compilation unit). These calls get put into | |
894 | our constructor initialization function. BODY is the function | |
895 | body, so far, of our constructor initialization function, to which we | |
896 | add the calls. */ | |
897 | ||
898 | static bool | |
899 | register_all_pairs (tree body) | |
900 | { | |
901 | bool registered_at_least_one = false; | |
b208ba40 | 902 | vec<tree> *vtbl_ptr_array = NULL; |
2077db1b CT |
903 | unsigned j; |
904 | ||
905 | for (j = 0; j < num_vtable_map_nodes; ++j) | |
906 | { | |
907 | struct vtbl_map_node *current = vtbl_map_nodes_vec[j]; | |
908 | unsigned i = 0; | |
909 | tree base_class = current->class_info->class_type; | |
910 | tree base_ptr_var_decl = current->vtbl_map_decl; | |
911 | tree arg1; | |
912 | tree arg2; | |
913 | tree new_type; | |
914 | tree str1 = NULL_TREE; | |
915 | tree str2 = NULL_TREE; | |
916 | size_t size_hint; | |
917 | tree size_hint_arg; | |
918 | ||
919 | gcc_assert (current->class_info != NULL); | |
920 | ||
921 | ||
922 | if (flag_vtv_debug) | |
923 | str1 = build_string_from_id (DECL_NAME (base_ptr_var_decl)); | |
924 | ||
925 | new_type = build_pointer_type (TREE_TYPE (base_ptr_var_decl)); | |
926 | arg1 = build1 (ADDR_EXPR, new_type, base_ptr_var_decl); | |
927 | ||
b208ba40 CT |
928 | /* We need a fresh vector for each iteration. */ |
929 | if (vtbl_ptr_array) | |
930 | vec_free (vtbl_ptr_array); | |
931 | ||
932 | vec_alloc (vtbl_ptr_array, 10); | |
2077db1b CT |
933 | |
934 | for (i = 0; i < num_vtable_map_nodes; ++i) | |
935 | if (bitmap_bit_p (current->class_info->descendants, i)) | |
936 | { | |
937 | struct vtbl_map_node *vtbl_class_node = vtbl_map_nodes_vec[i]; | |
938 | tree class_type = vtbl_class_node->class_info->class_type; | |
939 | ||
940 | if (class_type | |
941 | && (TREE_CODE (class_type) == RECORD_TYPE)) | |
942 | { | |
943 | bool already_registered; | |
944 | ||
945 | tree binfo = TYPE_BINFO (class_type); | |
946 | tree vtable_decl; | |
947 | bool vtable_should_be_output = false; | |
948 | ||
949 | vtable_decl = CLASSTYPE_VTABLES (class_type); | |
950 | ||
951 | /* Handle main vtable for this class. */ | |
952 | ||
953 | if (vtable_decl) | |
954 | { | |
955 | vtable_should_be_output = TREE_ASM_WRITTEN (vtable_decl); | |
956 | str2 = build_string_from_id (DECL_NAME (vtable_decl)); | |
957 | } | |
958 | ||
959 | if (vtable_decl && vtable_should_be_output) | |
960 | { | |
961 | tree vtable_address = build_vtbl_address (binfo); | |
962 | ||
963 | already_registered = check_and_record_registered_pairs | |
964 | (vtable_decl, | |
965 | vtable_address, | |
966 | base_class); | |
967 | ||
968 | ||
969 | if (!already_registered) | |
970 | { | |
b208ba40 | 971 | vtbl_ptr_array->safe_push (vtable_address); |
2077db1b CT |
972 | |
973 | /* Find and handle any 'extra' vtables associated | |
974 | with this class, via virtual inheritance. */ | |
975 | register_construction_vtables (base_class, class_type, | |
b208ba40 | 976 | vtbl_ptr_array); |
2077db1b CT |
977 | |
978 | /* Find and handle any 'extra' vtables associated | |
979 | with this class, via multiple inheritance. */ | |
980 | register_other_binfo_vtables (binfo, base_class, | |
b208ba40 | 981 | vtbl_ptr_array); |
2077db1b CT |
982 | } |
983 | } | |
984 | } | |
985 | } | |
b208ba40 | 986 | current_set_size = vtbl_ptr_array->length(); |
2077db1b CT |
987 | |
988 | /* Sometimes we need to initialize the set symbol even if we are | |
989 | not adding any vtable pointers to the set in the current | |
990 | compilation unit. In that case, we need to initialize the | |
991 | set to our best guess as to what the eventual size of the set | |
992 | hash table will be (to prevent having to re-size the hash | |
993 | table later). */ | |
994 | ||
995 | size_hint = guess_num_vtable_pointers (current->class_info); | |
996 | ||
997 | /* If we have added vtable pointers to the set in this | |
998 | compilation unit, adjust the size hint for the set's hash | |
999 | table appropriately. */ | |
b208ba40 CT |
1000 | if (vtbl_ptr_array->length() > 0) |
1001 | { | |
1002 | unsigned len = vtbl_ptr_array->length(); | |
1003 | while ((size_t) len > size_hint) | |
1004 | size_hint <<= 1; | |
1005 | } | |
2077db1b CT |
1006 | size_hint_arg = build_int_cst (size_type_node, size_hint); |
1007 | ||
1008 | /* Get the key-buffer argument. */ | |
1009 | arg2 = build_key_buffer_arg (base_ptr_var_decl); | |
1010 | ||
1011 | if (str2 == NULL_TREE) | |
1012 | str2 = build_string_literal (strlen ("unknown") + 1, | |
1013 | "unknown"); | |
1014 | ||
1015 | if (flag_vtv_debug) | |
1016 | output_set_info (current->class_info->class_type, | |
b208ba40 | 1017 | *vtbl_ptr_array); |
2077db1b | 1018 | |
b208ba40 | 1019 | if (vtbl_ptr_array->length() > 1) |
2077db1b | 1020 | { |
b208ba40 | 1021 | insert_call_to_register_set (current->class_name, |
2077db1b CT |
1022 | vtbl_ptr_array, body, arg1, arg2, |
1023 | size_hint_arg); | |
1024 | registered_at_least_one = true; | |
1025 | } | |
b208ba40 | 1026 | else |
2077db1b CT |
1027 | { |
1028 | ||
b208ba40 | 1029 | if (vtbl_ptr_array->length() > 0 |
2077db1b | 1030 | || (current->is_used |
c203e8a7 | 1031 | || (current->registered->size() > 0))) |
2077db1b | 1032 | { |
b208ba40 | 1033 | insert_call_to_register_pair (vtbl_ptr_array, |
2077db1b CT |
1034 | arg1, arg2, size_hint_arg, str1, |
1035 | str2, body); | |
1036 | registered_at_least_one = true; | |
1037 | } | |
1038 | } | |
1039 | ||
1040 | if (flag_vtv_counts && current_set_size > 0) | |
1041 | write_out_current_set_data (base_class, current_set_size); | |
1042 | ||
1043 | } | |
1044 | ||
1045 | return registered_at_least_one; | |
1046 | } | |
1047 | ||
1048 | /* Given a tree containing a class type (CLASS_TYPE), this function | |
1049 | finds and returns the class hierarchy node for that class in our | |
1050 | data structure. */ | |
1051 | ||
1052 | static struct vtv_graph_node * | |
1053 | find_graph_node (tree class_type) | |
1054 | { | |
1055 | struct vtbl_map_node *vtbl_node; | |
1056 | ||
1057 | vtbl_node = vtbl_map_get_node (TYPE_MAIN_VARIANT (class_type)); | |
1058 | if (vtbl_node) | |
1059 | return vtbl_node->class_info; | |
1060 | ||
1061 | return NULL; | |
1062 | } | |
1063 | ||
1064 | /* Add base class/derived class pair to our internal class hierarchy | |
1065 | data structure. BASE_NODE is our vtv_graph_node that corresponds | |
1066 | to a base class. DERIVED_NODE is our vtv_graph_node that | |
1067 | corresponds to a class that is a descendant of the base class | |
1068 | (possibly the base class itself). */ | |
1069 | ||
1070 | static void | |
1071 | add_hierarchy_pair (struct vtv_graph_node *base_node, | |
1072 | struct vtv_graph_node *derived_node) | |
1073 | { | |
1074 | (base_node->children).safe_push (derived_node); | |
1075 | (derived_node->parents).safe_push (base_node); | |
1076 | } | |
1077 | ||
1078 | /* This functions adds a new base class/derived class relationship to | |
1079 | our class hierarchy data structure. Both parameters are trees | |
1080 | representing the class types, i.e. RECORD_TYPE trees. | |
1081 | DERIVED_CLASS can be the same as BASE_CLASS. */ | |
1082 | ||
1083 | static void | |
1084 | update_class_hierarchy_information (tree base_class, | |
1085 | tree derived_class) | |
1086 | { | |
1087 | struct vtv_graph_node *base_node = find_graph_node (base_class); | |
1088 | struct vtv_graph_node *derived_node = find_graph_node (derived_class); | |
1089 | ||
1090 | add_hierarchy_pair (base_node, derived_node); | |
1091 | } | |
1092 | ||
1093 | ||
1094 | static void | |
1095 | write_out_vtv_count_data (void) | |
1096 | { | |
1097 | static int vtv_count_log_fd = -1; | |
1098 | char buffer[1024]; | |
1099 | int unused_vtbl_map_vars = 0; | |
1100 | int bytes_written __attribute__ ((unused)); | |
1101 | char *file_name = get_log_file_name ("vtv_count_data.log"); | |
1102 | ||
1103 | if (vtv_count_log_fd == -1) | |
1104 | vtv_count_log_fd = open (file_name, | |
1105 | O_WRONLY | O_APPEND | O_CREAT, S_IRWXU); | |
1106 | if (vtv_count_log_fd == -1) | |
1107 | { | |
b208ba40 CT |
1108 | warning_at (UNKNOWN_LOCATION, 0, |
1109 | "unable to open log file %<vtv_count_data.log%>: %m"); | |
2077db1b CT |
1110 | return; |
1111 | } | |
1112 | ||
1113 | for (unsigned i = 0; i < num_vtable_map_nodes; ++i) | |
1114 | { | |
1115 | struct vtbl_map_node *current = vtbl_map_nodes_vec[i]; | |
1116 | if (!current->is_used | |
c203e8a7 | 1117 | && current->registered->size() == 0) |
2077db1b CT |
1118 | unused_vtbl_map_vars++; |
1119 | } | |
1120 | ||
1121 | snprintf (buffer, sizeof (buffer), "%s %d %d %d %d %d\n", | |
1122 | main_input_filename, total_num_virtual_calls, | |
1123 | total_num_verified_vcalls, num_calls_to_regset, | |
1124 | num_calls_to_regpair, unused_vtbl_map_vars); | |
1125 | ||
1126 | bytes_written = write (vtv_count_log_fd, buffer, strlen (buffer)); | |
1127 | } | |
1128 | ||
1129 | /* This function calls register_all_pairs, which actually generates | |
1130 | all the calls to __VLTRegisterPair (in the verification constructor | |
1131 | init function). It also generates the calls to | |
1132 | __VLTChangePermission, if the verification constructor init | |
1133 | function is going into the preinit array. INIT_ROUTINE_BODY is | |
1134 | the body of our constructior initialization function, to which we | |
1135 | add our function calls.*/ | |
1136 | ||
1137 | bool | |
1138 | vtv_register_class_hierarchy_information (tree init_routine_body) | |
1139 | { | |
1140 | bool registered_something = false; | |
1141 | ||
1142 | init_functions (); | |
1143 | ||
1144 | if (num_vtable_map_nodes == 0) | |
1145 | return false; | |
1146 | ||
1147 | /* Add class hierarchy pairs to the vtable map data structure. */ | |
1148 | registered_something = register_all_pairs (init_routine_body); | |
1149 | ||
1150 | if (flag_vtv_counts) | |
1151 | write_out_vtv_count_data (); | |
1152 | ||
1153 | return registered_something; | |
1154 | } | |
1155 | ||
1156 | ||
1157 | /* Generate the special constructor function that calls | |
1158 | __VLTChangePermission and __VLTRegisterPairs, and give it a very | |
1159 | high initialization priority. */ | |
1160 | ||
1161 | void | |
1162 | vtv_generate_init_routine (void) | |
1163 | { | |
1164 | tree init_routine_body; | |
1165 | bool vtable_classes_found = false; | |
1166 | ||
1167 | push_lang_context (lang_name_c); | |
1168 | ||
1169 | /* The priority for this init function (constructor) is carefully | |
1170 | chosen so that it will happen after the calls to unprotect the | |
1171 | memory used for vtable verification and before the memory is | |
1172 | protected again. */ | |
1173 | init_routine_body = vtv_start_verification_constructor_init_function (); | |
1174 | ||
1175 | vtable_classes_found = | |
1176 | vtv_register_class_hierarchy_information (init_routine_body); | |
1177 | ||
1178 | if (vtable_classes_found) | |
1179 | { | |
1180 | tree vtv_fndecl = | |
1181 | vtv_finish_verification_constructor_init_function (init_routine_body); | |
1182 | TREE_STATIC (vtv_fndecl) = 1; | |
1183 | TREE_USED (vtv_fndecl) = 1; | |
1184 | DECL_PRESERVE_P (vtv_fndecl) = 1; | |
1185 | if (flag_vtable_verify == VTV_PREINIT_PRIORITY) | |
f085f27e | 1186 | DECL_STATIC_CONSTRUCTOR (vtv_fndecl) = 0; |
2077db1b CT |
1187 | |
1188 | gimplify_function_tree (vtv_fndecl); | |
1189 | cgraph_add_new_function (vtv_fndecl, false); | |
1190 | ||
1191 | cgraph_process_new_functions (); | |
f085f27e CT |
1192 | |
1193 | if (flag_vtable_verify == VTV_PREINIT_PRIORITY) | |
1194 | assemble_vtv_preinit_initializer (vtv_fndecl); | |
1195 | ||
2077db1b CT |
1196 | } |
1197 | pop_lang_context (); | |
1198 | } | |
1199 | ||
1200 | /* This funtion takes a tree containing a class type (BASE_TYPE), and | |
1201 | it either finds the existing vtbl_map_node for that class in our | |
1202 | data structure, or it creates a new node and adds it to the data | |
1203 | structure if there is not one for the class already. As part of | |
1204 | this process it also creates the global vtable map variable for the | |
1205 | class. */ | |
1206 | ||
1207 | struct vtbl_map_node * | |
1208 | vtable_find_or_create_map_decl (tree base_type) | |
1209 | { | |
1210 | char *var_name = NULL; | |
1211 | struct vtbl_map_node *vtable_map_node = NULL; | |
1212 | ||
1213 | /* Verify the type has an associated vtable. */ | |
1214 | if (!TYPE_BINFO (base_type) || !BINFO_VTABLE (TYPE_BINFO (base_type))) | |
1215 | return NULL; | |
1216 | ||
1217 | /* Create map lookup symbol for base class */ | |
1218 | var_name = get_mangled_vtable_map_var_name (base_type); | |
1219 | ||
1220 | /* We've already created the variable; just look it. */ | |
1221 | vtable_map_node = vtbl_map_get_node (TYPE_MAIN_VARIANT (base_type)); | |
1222 | ||
1223 | if (!vtable_map_node || (vtable_map_node->vtbl_map_decl == NULL_TREE)) | |
1224 | { | |
1225 | /* If we haven't already created the *__vtable_map global | |
1226 | variable for this class, do so now, and add it to the | |
1227 | varpool, to make sure it gets saved and written out. */ | |
1228 | ||
1229 | tree var_decl = NULL; | |
1230 | tree var_type = build_pointer_type (void_type_node); | |
1231 | tree initial_value = integer_zero_node; | |
1232 | ||
1233 | var_decl = build_decl (UNKNOWN_LOCATION, VAR_DECL, | |
1234 | get_identifier (var_name), var_type); | |
1235 | ||
1236 | DECL_EXTERNAL (var_decl) = 0; | |
1237 | TREE_STATIC (var_decl) = 1; | |
1238 | DECL_VISIBILITY (var_decl) = VISIBILITY_HIDDEN; | |
1239 | SET_DECL_ASSEMBLER_NAME (var_decl, get_identifier (var_name)); | |
1240 | DECL_ARTIFICIAL (var_decl) = 1; | |
1241 | /* We cannot mark this variable as read-only because we want to be | |
1242 | able to write to it at runtime. */ | |
1243 | TREE_READONLY (var_decl) = 0; | |
1244 | DECL_IGNORED_P (var_decl) = 1; | |
1245 | DECL_PRESERVE_P (var_decl) = 1; | |
1246 | ||
1247 | /* Put these mmap variables in thr .vtable_map_vars section, so | |
1248 | we can find and protect them. */ | |
1249 | ||
f961457f | 1250 | set_decl_section_name (var_decl, ".vtable_map_vars"); |
e257a17c | 1251 | symtab_get_node (var_decl)->implicit_section = true; |
2077db1b CT |
1252 | DECL_INITIAL (var_decl) = initial_value; |
1253 | ||
1254 | comdat_linkage (var_decl); | |
1255 | ||
1256 | varpool_finalize_decl (var_decl); | |
1257 | if (!vtable_map_node) | |
1258 | vtable_map_node = | |
1259 | find_or_create_vtbl_map_node (TYPE_MAIN_VARIANT (base_type)); | |
1260 | if (vtable_map_node->vtbl_map_decl == NULL_TREE) | |
1261 | vtable_map_node->vtbl_map_decl = var_decl; | |
1262 | } | |
1263 | ||
1264 | gcc_assert (vtable_map_node); | |
1265 | return vtable_map_node; | |
1266 | } | |
1267 | ||
1268 | /* This function is used to build up our class hierarchy data for a | |
1269 | particular class. TYPE is the record_type tree node for the | |
1270 | class. */ | |
1271 | ||
1272 | static void | |
1273 | vtv_insert_single_class_info (tree type) | |
1274 | { | |
1275 | if (flag_vtable_verify) | |
1276 | { | |
1277 | tree binfo = TYPE_BINFO (type); | |
1278 | tree base_binfo; | |
1279 | struct vtbl_map_node *own_map; | |
1280 | int i; | |
1281 | ||
1282 | /* First make sure to create the map for this record type. */ | |
1283 | own_map = vtable_find_or_create_map_decl (type); | |
1284 | if (own_map == NULL) | |
1285 | return; | |
1286 | ||
1287 | /* Go through the list of all base classes for the current | |
1288 | (derived) type, make sure the *__vtable_map global variable | |
1289 | for the base class exists, and add the base class/derived | |
1290 | class pair to the class hierarchy information we are | |
1291 | accumulating (for vtable pointer verification). */ | |
1292 | for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
1293 | { | |
1294 | tree tree_val = BINFO_TYPE (base_binfo); | |
1295 | struct vtbl_map_node *vtable_map_node = NULL; | |
1296 | ||
1297 | vtable_map_node = vtable_find_or_create_map_decl (tree_val); | |
1298 | ||
1299 | if (vtable_map_node != NULL) | |
1300 | update_class_hierarchy_information (tree_val, type); | |
1301 | } | |
1302 | } | |
1303 | } | |
1304 | ||
1305 | /* This function adds classes we are interested in to a list of | |
1306 | classes. RECORD is the record_type node for the class we are | |
1307 | adding to the list. */ | |
1308 | ||
1309 | void | |
1310 | vtv_save_class_info (tree record) | |
1311 | { | |
1312 | if (!flag_vtable_verify || TREE_CODE (record) == UNION_TYPE) | |
1313 | return; | |
1314 | ||
1315 | if (!vlt_saved_class_info) | |
1316 | vec_alloc (vlt_saved_class_info, 10); | |
1317 | ||
1318 | gcc_assert (TREE_CODE (record) == RECORD_TYPE); | |
1319 | ||
1320 | vec_safe_push (vlt_saved_class_info, record); | |
1321 | } | |
1322 | ||
1323 | ||
1324 | /* This function goes through the list of classes we saved and calls | |
1325 | vtv_insert_single_class_info on each one, to build up our class | |
1326 | hierarchy data structure. */ | |
1327 | ||
1328 | void | |
1329 | vtv_recover_class_info (void) | |
1330 | { | |
1331 | tree current_class; | |
1332 | unsigned i; | |
1333 | ||
1334 | if (vlt_saved_class_info) | |
1335 | { | |
1336 | for (i = 0; i < vlt_saved_class_info->length(); ++i) | |
1337 | { | |
1338 | current_class = (*vlt_saved_class_info)[i]; | |
1339 | gcc_assert (TREE_CODE (current_class) == RECORD_TYPE); | |
1340 | vtv_insert_single_class_info (current_class); | |
1341 | } | |
1342 | } | |
1343 | } | |
1344 | ||
1345 | #include "gt-cp-vtable-class-hierarchy.h" |