1 /* Copyright (C) 2013-2015 Free Software Foundation, Inc.
3 This file is part of GCC.
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
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
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/>. */
19 /* Virtual Table Pointer Security Pass - Detect corruption of vtable pointers
20 before using them for virtual method dispatches. */
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
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
53 To find and reference the set of valid vtable pointers for any given
54 virtual class, we create a special global variable 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.
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
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.
103 This file contains code for the tree pass that goes through all the
104 statements in each basic block, looking for virtual calls, and
105 inserting a call to __VLTVerifyVtablePointer (with appropriate
106 arguments) before each one. It also contains the hash table
107 functions for the data structures used for collecting the class
108 hierarchy data and building/maintaining the vtable map variable data
109 are defined in gcc/vtable-verify.h. These data structures are
110 shared with the code in the C++ front end that collects the class
111 hierarchy & vtable information and generates the vtable map
112 variables (see cp/vtable-class-hierarchy.c). This tree pass should
113 run just before the gimple is converted to RTL.
115 Some implementation details for this pass:
117 To find all of the virtual calls, we iterate through all the
118 gimple statements in each basic block, looking for any call
119 statement with the code "OBJ_TYPE_REF". Once we have found the
120 virtual call, we need to find the vtable pointer through which the
121 call is being made, and the type of the object containing the
122 pointer (to find the appropriate vtable map variable). We then use
123 these to build a call to __VLTVerifyVtablePointer, passing the
124 vtable map variable, and the vtable pointer. We insert the
125 verification call just after the gimple statement that gets the
126 vtable pointer out of the object, and we update the next
127 statement to depend on the result returned from
128 __VLTVerifyVtablePointer (the vtable pointer value), to ensure
129 subsequent compiler phases don't remove or reorder the call (it's no
130 good to have the verification occur after the virtual call, for
131 example). To find the vtable pointer being used (and the type of
132 the object) we search backwards through the def_stmts chain from the
133 virtual call (see verify_bb_vtables for more details). */
137 #include "coretypes.h"
138 #include "hash-set.h"
146 #include "fold-const.h"
149 #include "hard-reg-set.h"
151 #include "function.h"
152 #include "dominance.h"
154 #include "basic-block.h"
155 #include "tree-ssa-alias.h"
156 #include "internal-fn.h"
157 #include "gimple-expr.h"
160 #include "gimple-iterator.h"
161 #include "gimple-ssa.h"
162 #include "tree-phinodes.h"
163 #include "ssa-iterators.h"
164 #include "stringpool.h"
165 #include "tree-ssanames.h"
166 #include "tree-pass.h"
169 #include "vtable-verify.h"
171 unsigned num_vtable_map_nodes
= 0;
172 int total_num_virtual_calls
= 0;
173 int total_num_verified_vcalls
= 0;
175 extern GTY(()) tree verify_vtbl_ptr_fndecl
;
176 tree verify_vtbl_ptr_fndecl
= NULL_TREE
;
178 /* Keep track of whether or not any virtual call were verified. */
179 static bool any_verification_calls_generated
= false;
181 unsigned int vtable_verify_main (void);
184 /* The following few functions are for the vtbl pointer hash table
185 in the 'registered' field of the struct vtable_map_node. The hash
186 table keeps track of which vtable pointers have been used in
187 calls to __VLTRegisterPair with that particular vtable map variable. */
189 /* This function checks to see if a particular VTABLE_DECL and OFFSET are
190 already in the 'registered' hash table for NODE. */
193 vtbl_map_node_registration_find (struct vtbl_map_node
*node
,
197 struct vtable_registration key
;
198 struct vtable_registration
**slot
;
200 gcc_assert (node
&& node
->registered
);
202 key
.vtable_decl
= vtable_decl
;
203 slot
= node
->registered
->find_slot (&key
, NO_INSERT
);
208 for (i
= 0; i
< ((*slot
)->offsets
).length (); ++i
)
209 if ((*slot
)->offsets
[i
] == offset
)
216 /* This function inserts VTABLE_DECL and OFFSET into the 'registered'
217 hash table for NODE. It returns a boolean indicating whether or not
218 it actually inserted anything. */
221 vtbl_map_node_registration_insert (struct vtbl_map_node
*node
,
225 struct vtable_registration key
;
226 struct vtable_registration
**slot
;
227 bool inserted_something
= false;
229 if (!node
|| !node
->registered
)
232 key
.vtable_decl
= vtable_decl
;
233 slot
= node
->registered
->find_slot (&key
, INSERT
);
237 struct vtable_registration
*node
;
238 node
= XNEW (struct vtable_registration
);
239 node
->vtable_decl
= vtable_decl
;
241 (node
->offsets
).create (10);
242 (node
->offsets
).safe_push (offset
);
244 inserted_something
= true;
248 /* We found the vtable_decl slot; we need to see if it already
249 contains the offset. If not, we need to add the offset. */
252 for (i
= 0; i
< ((*slot
)->offsets
).length () && !found
; ++i
)
253 if ((*slot
)->offsets
[i
] == offset
)
258 ((*slot
)->offsets
).safe_push (offset
);
259 inserted_something
= true;
262 return inserted_something
;
265 /* Hashtable functions for vtable_registration hashtables. */
268 registration_hasher::hash (const vtable_registration
*p
)
270 const struct vtable_registration
*n
= (const struct vtable_registration
*) p
;
271 return (hashval_t
) (DECL_UID (n
->vtable_decl
));
275 registration_hasher::equal (const vtable_registration
*p1
,
276 const vtable_registration
*p2
)
278 const struct vtable_registration
*n1
=
279 (const struct vtable_registration
*) p1
;
280 const struct vtable_registration
*n2
=
281 (const struct vtable_registration
*) p2
;
282 return (DECL_UID (n1
->vtable_decl
) == DECL_UID (n2
->vtable_decl
));
285 /* End of hashtable functions for "registered" hashtables. */
289 /* Hashtable definition and functions for vtbl_map_hash. */
291 struct vtbl_map_hasher
: typed_noop_remove
<struct vtbl_map_node
>
293 typedef struct vtbl_map_node
*value_type
;
294 typedef struct vtbl_map_node
*compare_type
;
295 static inline hashval_t
hash (const vtbl_map_node
*);
296 static inline bool equal (const vtbl_map_node
*, const vtbl_map_node
*);
299 /* Returns a hash code for P. */
302 vtbl_map_hasher::hash (const vtbl_map_node
*p
)
304 const struct vtbl_map_node n
= *((const struct vtbl_map_node
*) p
);
305 return (hashval_t
) IDENTIFIER_HASH_VALUE (n
.class_name
);
308 /* Returns nonzero if P1 and P2 are equal. */
311 vtbl_map_hasher::equal (const vtbl_map_node
*p1
, const vtbl_map_node
*p2
)
313 const struct vtbl_map_node n1
= *((const struct vtbl_map_node
*) p1
);
314 const struct vtbl_map_node n2
= *((const struct vtbl_map_node
*) p2
);
315 return (IDENTIFIER_HASH_VALUE (n1
.class_name
) ==
316 IDENTIFIER_HASH_VALUE (n2
.class_name
));
319 /* Here are the two structures into which we insert vtable map nodes.
320 We use two data structures because of the vastly different ways we need
321 to find the nodes for various tasks (see comments in vtable-verify.h
324 typedef hash_table
<vtbl_map_hasher
> vtbl_map_table_type
;
325 typedef vtbl_map_table_type::iterator vtbl_map_iterator_type
;
327 /* Vtable map variable nodes stored in a hash table. */
328 static vtbl_map_table_type
*vtbl_map_hash
;
330 /* Vtable map variable nodes stored in a vector. */
331 vec
<struct vtbl_map_node
*> vtbl_map_nodes_vec
;
333 /* Return vtbl_map node for CLASS_NAME without creating a new one. */
335 struct vtbl_map_node
*
336 vtbl_map_get_node (tree class_type
)
338 struct vtbl_map_node key
;
339 struct vtbl_map_node
**slot
;
341 tree class_type_decl
;
343 unsigned int type_quals
;
348 gcc_assert (TREE_CODE (class_type
) == RECORD_TYPE
);
351 /* Find the TYPE_DECL for the class. */
352 class_type_decl
= TYPE_NAME (class_type
);
354 /* Verify that there aren't any qualifiers on the type. */
355 type_quals
= TYPE_QUALS (TREE_TYPE (class_type_decl
));
356 gcc_assert (type_quals
== TYPE_UNQUALIFIED
);
358 /* Get the mangled name for the unqualified type. */
359 gcc_assert (HAS_DECL_ASSEMBLER_NAME_P (class_type_decl
));
360 class_name
= DECL_ASSEMBLER_NAME (class_type_decl
);
362 key
.class_name
= class_name
;
363 slot
= (struct vtbl_map_node
**) vtbl_map_hash
->find_slot (&key
, NO_INSERT
);
369 /* Return vtbl_map node assigned to BASE_CLASS_TYPE. Create new one
372 struct vtbl_map_node
*
373 find_or_create_vtbl_map_node (tree base_class_type
)
375 struct vtbl_map_node key
;
376 struct vtbl_map_node
*node
;
377 struct vtbl_map_node
**slot
;
378 tree class_type_decl
;
379 unsigned int type_quals
;
382 vtbl_map_hash
= new vtbl_map_table_type (10);
384 /* Find the TYPE_DECL for the class. */
385 class_type_decl
= TYPE_NAME (base_class_type
);
387 /* Verify that there aren't any type qualifiers on type. */
388 type_quals
= TYPE_QUALS (TREE_TYPE (class_type_decl
));
389 gcc_assert (type_quals
== TYPE_UNQUALIFIED
);
391 gcc_assert (HAS_DECL_ASSEMBLER_NAME_P (class_type_decl
));
392 key
.class_name
= DECL_ASSEMBLER_NAME (class_type_decl
);
393 slot
= (struct vtbl_map_node
**) vtbl_map_hash
->find_slot (&key
, INSERT
);
398 node
= XNEW (struct vtbl_map_node
);
399 node
->vtbl_map_decl
= NULL_TREE
;
400 node
->class_name
= key
.class_name
;
401 node
->uid
= num_vtable_map_nodes
++;
403 node
->class_info
= XNEW (struct vtv_graph_node
);
404 node
->class_info
->class_type
= base_class_type
;
405 node
->class_info
->class_uid
= node
->uid
;
406 node
->class_info
->num_processed_children
= 0;
408 (node
->class_info
->parents
).create (4);
409 (node
->class_info
->children
).create (4);
411 node
->registered
= new register_table_type (16);
413 node
->is_used
= false;
415 vtbl_map_nodes_vec
.safe_push (node
);
416 gcc_assert (vtbl_map_nodes_vec
[node
->uid
] == node
);
422 /* End of hashtable functions for vtable_map variables hash table. */
424 /* Given a gimple STMT, this function checks to see if the statement
425 is an assignment, the rhs of which is getting the vtable pointer
426 value out of an object. (i.e. it's the value we need to verify
427 because its the vtable pointer that will be used for a virtual
431 is_vtable_assignment_stmt (gimple stmt
)
434 if (gimple_code (stmt
) != GIMPLE_ASSIGN
)
438 tree lhs
= gimple_assign_lhs (stmt
);
439 tree rhs
= gimple_assign_rhs1 (stmt
);
441 if (TREE_CODE (lhs
) != SSA_NAME
)
444 if (TREE_CODE (rhs
) != COMPONENT_REF
)
447 if (! (TREE_OPERAND (rhs
, 1))
448 || (TREE_CODE (TREE_OPERAND (rhs
, 1)) != FIELD_DECL
))
451 if (! DECL_VIRTUAL_P (TREE_OPERAND (rhs
, 1)))
458 /* This function attempts to recover the declared class of an object
459 that is used in making a virtual call. We try to get the type from
460 the type cast in the gimple assignment statement that extracts the
461 vtable pointer from the object (DEF_STMT). The gimple statement
462 usually looks something like this:
464 D.2201_4 = MEM[(struct Event *)this_1(D)]._vptr.Event */
467 extract_object_class_type (tree rhs
)
469 tree result
= NULL_TREE
;
471 /* Try to find and extract the type cast from that stmt. */
472 if (TREE_CODE (rhs
) == COMPONENT_REF
)
474 tree op0
= TREE_OPERAND (rhs
, 0);
475 tree op1
= TREE_OPERAND (rhs
, 1);
477 if (TREE_CODE (op1
) == FIELD_DECL
478 && DECL_VIRTUAL_P (op1
))
480 if (TREE_CODE (op0
) == COMPONENT_REF
481 && TREE_CODE (TREE_OPERAND (op0
, 0)) == MEM_REF
482 && TREE_CODE (TREE_TYPE (TREE_OPERAND (op0
, 0)))== RECORD_TYPE
)
483 result
= TREE_TYPE (TREE_OPERAND (op0
, 0));
485 result
= TREE_TYPE (op0
);
487 else if (TREE_CODE (op0
) == COMPONENT_REF
)
489 result
= extract_object_class_type (op0
);
490 if (result
== NULL_TREE
491 && TREE_CODE (op1
) == COMPONENT_REF
)
492 result
= extract_object_class_type (op1
);
499 /* This function traces forward through the def-use chain of an SSA
500 variable to see if it ever gets used in a virtual function call. It
501 returns a boolean indicating whether or not it found a virtual call in
505 var_is_used_for_virtual_call_p (tree lhs
, int *mem_ref_depth
)
507 imm_use_iterator imm_iter
;
508 bool found_vcall
= false;
511 if (TREE_CODE (lhs
) != SSA_NAME
)
514 if (*mem_ref_depth
> 2)
517 /* Iterate through the immediate uses of the current variable. If
518 it's a virtual function call, we're done. Otherwise, if there's
519 an LHS for the use stmt, add the ssa var to the work list
520 (assuming it's not already in the list and is not a variable
521 we've already examined. */
523 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, lhs
)
525 gimple stmt2
= USE_STMT (use_p
);
527 if (is_gimple_call (stmt2
))
529 tree fncall
= gimple_call_fn (stmt2
);
530 if (fncall
&& TREE_CODE (fncall
) == OBJ_TYPE_REF
)
535 else if (gimple_code (stmt2
) == GIMPLE_PHI
)
537 found_vcall
= var_is_used_for_virtual_call_p
538 (gimple_phi_result (stmt2
),
541 else if (is_gimple_assign (stmt2
))
543 tree rhs
= gimple_assign_rhs1 (stmt2
);
544 if (TREE_CODE (rhs
) == ADDR_EXPR
545 || TREE_CODE (rhs
) == MEM_REF
)
546 *mem_ref_depth
= *mem_ref_depth
+ 1;
548 if (TREE_CODE (rhs
) == COMPONENT_REF
)
550 while (TREE_CODE (TREE_OPERAND (rhs
, 0)) == COMPONENT_REF
)
551 rhs
= TREE_OPERAND (rhs
, 0);
553 if (TREE_CODE (TREE_OPERAND (rhs
, 0)) == ADDR_EXPR
554 || TREE_CODE (TREE_OPERAND (rhs
, 0)) == MEM_REF
)
555 *mem_ref_depth
= *mem_ref_depth
+ 1;
558 if (*mem_ref_depth
< 3)
559 found_vcall
= var_is_used_for_virtual_call_p
560 (gimple_assign_lhs (stmt2
),
574 /* Search through all the statements in a basic block (BB), searching
575 for virtual method calls. For each virtual method dispatch, find
576 the vptr value used, and the statically declared type of the
577 object; retrieve the vtable map variable for the type of the
578 object; generate a call to __VLTVerifyVtablePointer; and insert the
579 generated call into the basic block, after the point where the vptr
580 value is gotten out of the object and before the virtual method
581 dispatch. Make the virtual method dispatch depend on the return
582 value from the verification call, so that subsequent optimizations
583 cannot reorder the two calls. */
586 verify_bb_vtables (basic_block bb
)
590 gimple_stmt_iterator gsi_vtbl_assign
;
591 gimple_stmt_iterator gsi_virtual_call
;
594 gsi_virtual_call
= gsi_start (stmts
);
595 for (; !gsi_end_p (gsi_virtual_call
); gsi_next (&gsi_virtual_call
))
597 stmt
= gsi_stmt (gsi_virtual_call
);
599 /* Count virtual calls. */
600 if (is_gimple_call (stmt
))
602 tree fncall
= gimple_call_fn (stmt
);
603 if (fncall
&& TREE_CODE (fncall
) == OBJ_TYPE_REF
)
604 total_num_virtual_calls
++;
607 if (is_vtable_assignment_stmt (stmt
))
609 tree lhs
= gimple_assign_lhs (stmt
);
610 tree vtbl_var_decl
= NULL_TREE
;
611 struct vtbl_map_node
*vtable_map_node
;
612 tree vtbl_decl
= NULL_TREE
;
614 const char *vtable_name
= "<unknown>";
617 int mem_ref_depth
= 0;
619 /* Make sure this vptr field access is for a virtual call. */
620 if (!var_is_used_for_virtual_call_p (lhs
, &mem_ref_depth
))
623 /* Now we have found the virtual method dispatch and
624 the preceding access of the _vptr.* field... Next
625 we need to find the statically declared type of
626 the object, so we can find and use the right
627 vtable map variable in the verification call. */
628 tree class_type
= extract_object_class_type
629 (gimple_assign_rhs1 (stmt
));
631 gsi_vtbl_assign
= gsi_for_stmt (stmt
);
634 && (TREE_CODE (class_type
) == RECORD_TYPE
)
635 && TYPE_BINFO (class_type
))
637 /* Get the vtable VAR_DECL for the type. */
638 vtbl_var_decl
= BINFO_VTABLE (TYPE_BINFO (class_type
));
640 if (TREE_CODE (vtbl_var_decl
) == POINTER_PLUS_EXPR
)
641 vtbl_var_decl
= TREE_OPERAND (TREE_OPERAND (vtbl_var_decl
, 0),
644 gcc_assert (vtbl_var_decl
);
646 vtbl_decl
= vtbl_var_decl
;
647 vtable_map_node
= vtbl_map_get_node
648 (TYPE_MAIN_VARIANT (class_type
));
650 gcc_assert (verify_vtbl_ptr_fndecl
);
652 /* Given the vtable pointer for the base class of the
653 object, build the call to __VLTVerifyVtablePointer to
654 verify that the object's vtable pointer (contained in
655 lhs) is in the set of valid vtable pointers for the
658 if (vtable_map_node
&& vtable_map_node
->vtbl_map_decl
)
660 vtable_map_node
->is_used
= true;
661 vtbl_var_decl
= vtable_map_node
->vtbl_map_decl
;
663 if (TREE_CODE (vtbl_decl
) == VAR_DECL
)
664 vtable_name
= IDENTIFIER_POINTER (DECL_NAME (vtbl_decl
));
666 /* Call different routines if we are interested in
667 trace information to debug problems. */
670 int len1
= IDENTIFIER_LENGTH
671 (DECL_NAME (vtbl_var_decl
));
672 int len2
= strlen (vtable_name
);
674 call_stmt
= gimple_build_call
675 (verify_vtbl_ptr_fndecl
, 4,
678 (TREE_TYPE (vtbl_var_decl
)),
686 build_string_literal (len2
+ 1,
690 call_stmt
= gimple_build_call
691 (verify_vtbl_ptr_fndecl
, 2,
694 (TREE_TYPE (vtbl_var_decl
)),
699 /* Create a new SSA_NAME var to hold the call's
700 return value, and make the call_stmt use the
701 variable for that purpose. */
702 tmp0
= make_temp_ssa_name (TREE_TYPE (lhs
), NULL
, "VTV");
703 gimple_call_set_lhs (call_stmt
, tmp0
);
704 update_stmt (call_stmt
);
706 /* Replace all uses of lhs with tmp0. */
708 imm_use_iterator iterator
;
710 FOR_EACH_IMM_USE_STMT (use_stmt
, iterator
, lhs
)
713 if (use_stmt
== call_stmt
)
715 FOR_EACH_IMM_USE_ON_STMT (use_p
, iterator
)
716 SET_USE (use_p
, tmp0
);
717 update_stmt (use_stmt
);
723 /* Insert the new verification call just after the
724 statement that gets the vtable pointer out of the
726 gcc_assert (gsi_stmt (gsi_vtbl_assign
) == stmt
);
727 gsi_insert_after (&gsi_vtbl_assign
, call_stmt
,
730 any_verification_calls_generated
= true;
731 total_num_verified_vcalls
++;
738 /* Definition of this optimization pass. */
742 const pass_data pass_data_vtable_verify
=
744 GIMPLE_PASS
, /* type */
745 "vtable-verify", /* name */
746 OPTGROUP_NONE
, /* optinfo_flags */
747 TV_VTABLE_VERIFICATION
, /* tv_id */
748 ( PROP_cfg
| PROP_ssa
), /* properties_required */
749 0, /* properties_provided */
750 0, /* properties_destroyed */
751 0, /* todo_flags_start */
752 TODO_update_ssa
, /* todo_flags_finish */
755 class pass_vtable_verify
: public gimple_opt_pass
758 pass_vtable_verify (gcc::context
*ctxt
)
759 : gimple_opt_pass (pass_data_vtable_verify
, ctxt
)
762 /* opt_pass methods: */
763 virtual bool gate (function
*) { return (flag_vtable_verify
); }
764 virtual unsigned int execute (function
*);
766 }; // class pass_vtable_verify
768 /* Loop through all the basic blocks in the current function, passing them to
769 verify_bb_vtables, which searches for virtual calls, and inserts
770 calls to __VLTVerifyVtablePointer. */
773 pass_vtable_verify::execute (function
*fun
)
775 unsigned int ret
= 1;
778 FOR_ALL_BB_FN (bb
, fun
)
779 verify_bb_vtables (bb
);
787 make_pass_vtable_verify (gcc::context
*ctxt
)
789 return new pass_vtable_verify (ctxt
);
792 #include "gt-vtable-verify.h"