1 /* UndefinedBehaviorSanitizer, undefined behavior detector.
2 Copyright (C) 2014 Free Software Foundation, Inc.
3 Contributed by Jakub Jelinek <jakub@redhat.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
26 #include "basic-block.h"
34 #include "c-family/c-common.h"
35 #include "c-family/c-ubsan.h"
37 #include "internal-fn.h"
38 #include "stor-layout.h"
40 #include "fold-const.h"
41 #include "stringpool.h"
44 /* Test if we should instrument vptr access. */
47 cp_ubsan_instrument_vptr_p (tree type
)
49 if (!flag_rtti
|| flag_sanitize_undefined_trap_on_error
)
52 if (current_function_decl
53 && lookup_attribute ("no_sanitize_undefined",
54 DECL_ATTRIBUTES (current_function_decl
)))
59 type
= TYPE_MAIN_VARIANT (type
);
60 if (!CLASS_TYPE_P (type
) || !CLASSTYPE_VTABLES (type
))
67 /* Helper function for
68 cp_ubsan_maybe_instrument_{member_{call,access},downcast}.
69 Instrument vptr access. */
72 cp_ubsan_instrument_vptr (location_t loc
, tree op
, tree type
, bool is_addr
,
73 enum ubsan_null_ckind ckind
)
75 type
= TYPE_MAIN_VARIANT (type
);
76 const char *mangled
= mangle_type_string (type
);
77 hashval_t str_hash1
= htab_hash_string (mangled
);
78 hashval_t str_hash2
= iterative_hash (mangled
, strlen (mangled
), 0);
79 tree str_hash
= wide_int_to_tree (uint64_type_node
,
80 wi::uhwi (((uint64_t) str_hash1
<< 32)
83 op
= build_fold_addr_expr_loc (loc
, op
);
85 tree vptr
= fold_build3_loc (loc
, COMPONENT_REF
,
86 TREE_TYPE (TYPE_VFIELD (type
)),
87 build_fold_indirect_ref_loc (loc
, op
),
88 TYPE_VFIELD (type
), NULL_TREE
);
89 vptr
= fold_convert_loc (loc
, pointer_sized_int_node
, vptr
);
90 vptr
= fold_convert_loc (loc
, uint64_type_node
, vptr
);
91 if (ckind
== UBSAN_DOWNCAST_POINTER
)
92 vptr
= fold_build3 (COND_EXPR
, uint64_type_node
,
93 fold_build2 (NE_EXPR
, boolean_type_node
, op
,
94 build_zero_cst (TREE_TYPE (op
))),
95 vptr
, build_int_cst (uint64_type_node
, 0));
96 tree ti_decl
= get_tinfo_decl (type
);
98 tree ptype
= build_pointer_type (type
);
100 = build_call_expr_internal_loc (loc
, IFN_UBSAN_VPTR
,
101 void_type_node
, 5, op
, vptr
, str_hash
,
102 build_address (ti_decl
),
103 build_int_cst (ptype
, ckind
));
104 TREE_SIDE_EFFECTS (call
) = 1;
105 return fold_build2 (COMPOUND_EXPR
, TREE_TYPE (op
), call
, op
);
108 /* Helper function for
109 cp_ubsan_maybe_instrument_{member_{call,access},downcast}.
110 Instrument vptr access if it should be instrumented, otherwise return
114 cp_ubsan_maybe_instrument_vptr (location_t loc
, tree op
, tree type
,
115 bool is_addr
, enum ubsan_null_ckind ckind
)
117 if (!cp_ubsan_instrument_vptr_p (type
))
119 return cp_ubsan_instrument_vptr (loc
, op
, type
, is_addr
, ckind
);
122 /* Instrument a member call (but not constructor call) if needed. */
125 cp_ubsan_maybe_instrument_member_call (tree stmt
)
127 if (call_expr_nargs (stmt
) == 0)
129 tree
*opp
= &CALL_EXPR_ARG (stmt
, 0);
131 if (op
== error_mark_node
132 || !POINTER_TYPE_P (TREE_TYPE (op
)))
134 while (TREE_CODE (op
) == COMPOUND_EXPR
)
136 opp
= &TREE_OPERAND (op
, 1);
139 op
= cp_ubsan_maybe_instrument_vptr (EXPR_LOCATION (stmt
), op
,
140 TREE_TYPE (TREE_TYPE (op
)),
141 true, UBSAN_MEMBER_CALL
);
146 /* Data passed to cp_ubsan_check_member_access_r. */
148 struct cp_ubsan_check_member_access_data
150 hash_set
<tree
> *pset
;
154 static tree
cp_ubsan_check_member_access_r (tree
*, int *, void *);
156 /* Instrument a member access. */
159 cp_ubsan_maybe_instrument_member_access
160 (tree stmt
, cp_ubsan_check_member_access_data
*ucmd
)
162 if (DECL_ARTIFICIAL (TREE_OPERAND (stmt
, 1)))
165 tree base
= TREE_OPERAND (stmt
, 0);
166 if (!cp_ubsan_instrument_vptr_p (TREE_TYPE (base
)))
169 cp_walk_tree (&base
, cp_ubsan_check_member_access_r
, ucmd
, ucmd
->pset
);
171 base
= cp_ubsan_instrument_vptr (EXPR_LOCATION (stmt
), base
,
172 TREE_TYPE (base
), false,
173 UBSAN_MEMBER_ACCESS
);
174 TREE_OPERAND (stmt
, 0)
175 = build_fold_indirect_ref_loc (EXPR_LOCATION (stmt
), base
);
179 /* Attempt to instrument member accesses inside of the function.
180 cp_ubsan_maybe_instrument_member_access should be called on COMPONENT_REFs
181 in the GENERIC IL, but only when the field is actually accessed, not
182 merely when it's address is taken. Therefore we track in is_addr field
183 whether in the current context we are processing address taken
184 handled components or not. E.g. for &x->y[w->z] we want to call
185 cp_ubsan_maybe_instrument_member_access on *w.z COMPONENT_REF, but
189 cp_ubsan_check_member_access_r (tree
*stmt_p
, int *walk_subtrees
, void *data
)
191 tree stmt
= *stmt_p
, t
;
192 cp_ubsan_check_member_access_data
*ucmd
193 = (cp_ubsan_check_member_access_data
*) data
;
194 switch (TREE_CODE (stmt
))
197 t
= TREE_OPERAND (stmt
, 0);
198 while ((TREE_CODE (t
) == MEM_REF
|| INDIRECT_REF_P (t
))
199 && TREE_CODE (TREE_OPERAND (t
, 0)) == ADDR_EXPR
)
200 t
= TREE_OPERAND (TREE_OPERAND (t
, 0), 0);
201 if (handled_component_p (t
))
204 ucmd
->is_addr
= true;
205 cp_walk_tree (&t
, cp_ubsan_check_member_access_r
,
207 ucmd
->is_addr
= false;
212 t
= TREE_OPERAND (stmt
, 0);
213 if (TREE_CODE (t
) == ADDR_EXPR
)
216 t
= TREE_OPERAND (stmt
, 0);
217 cp_walk_tree (&t
, cp_ubsan_check_member_access_r
, data
, ucmd
->pset
);
221 if (!ucmd
->is_addr
&& cp_ubsan_maybe_instrument_member_access (stmt
, ucmd
))
228 if (ucmd
->is_addr
&& handled_component_p (stmt
))
230 int i
, len
= TREE_OPERAND_LENGTH (stmt
);
232 if (!handled_component_p (TREE_OPERAND (stmt
, 0)))
233 ucmd
->is_addr
= false;
234 for (i
= 0; i
< len
; i
++)
236 cp_walk_tree (&TREE_OPERAND (stmt
, i
),
237 cp_ubsan_check_member_access_r
, data
, ucmd
->pset
);
238 ucmd
->is_addr
= false;
240 ucmd
->is_addr
= true;
247 /* Instrument all member accesses inside GENERIC *T_P. */
250 cp_ubsan_instrument_member_accesses (tree
*t_p
)
252 if (cp_ubsan_instrument_vptr_p (NULL_TREE
))
255 cp_ubsan_check_member_access_data ucmd
;
257 ucmd
.is_addr
= false;
258 cp_walk_tree (t_p
, cp_ubsan_check_member_access_r
, &ucmd
, &pset
);
262 /* Instrument downcast. */
265 cp_ubsan_maybe_instrument_downcast (location_t loc
, tree type
, tree op
)
267 if (!POINTER_TYPE_P (type
)
268 || !POINTER_TYPE_P (TREE_TYPE (op
))
269 || !CLASS_TYPE_P (TREE_TYPE (type
))
270 || !CLASS_TYPE_P (TREE_TYPE (TREE_TYPE (op
)))
271 || !DERIVED_FROM_P (TREE_TYPE (TREE_TYPE (op
)), TREE_TYPE (type
)))
274 return cp_ubsan_maybe_instrument_vptr (loc
, op
, TREE_TYPE (type
), true,
275 TREE_CODE (type
) == POINTER_TYPE
276 ? UBSAN_DOWNCAST_POINTER
277 : UBSAN_DOWNCAST_REFERENCE
);
280 /* Instrument cast to virtual base. */
283 cp_ubsan_maybe_instrument_cast_to_vbase (location_t loc
, tree type
, tree op
)
285 return cp_ubsan_maybe_instrument_vptr (loc
, op
, type
, true,
286 UBSAN_CAST_TO_VBASE
);