1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32#include "gcc-common.h"
33
34
35#define TYPE_USERSPACE(TYPE) TYPE_LANG_FLAG_5(TYPE)
36
37__visible int plugin_is_GPL_compatible;
38
39static struct plugin_info structleak_plugin_info = {
40 .version = "20190125vanilla",
41 .help = "disable\tdo not activate plugin\n"
42 "byref\tinit structs passed by reference\n"
43 "byref-all\tinit anything passed by reference\n"
44 "verbose\tprint all initialized variables\n",
45};
46
47#define BYREF_STRUCT 1
48#define BYREF_ALL 2
49
50static bool verbose;
51static int byref;
52
53static tree handle_user_attribute(tree *node, tree name, tree args, int flags, bool *no_add_attrs)
54{
55 *no_add_attrs = true;
56
57
58 if (TREE_CODE(*node) != FIELD_DECL)
59 return NULL_TREE;
60
61 *no_add_attrs = false;
62 return NULL_TREE;
63}
64
65static struct attribute_spec user_attr = { };
66
67static void register_attributes(void *event_data, void *data)
68{
69 user_attr.name = "user";
70 user_attr.handler = handle_user_attribute;
71#if BUILDING_GCC_VERSION >= 4007
72 user_attr.affects_type_identity = true;
73#endif
74
75 register_attribute(&user_attr);
76}
77
78static tree get_field_type(tree field)
79{
80 return strip_array_types(TREE_TYPE(field));
81}
82
83static bool is_userspace_type(tree type)
84{
85 tree field;
86
87 for (field = TYPE_FIELDS(type); field; field = TREE_CHAIN(field)) {
88 tree fieldtype = get_field_type(field);
89 enum tree_code code = TREE_CODE(fieldtype);
90
91 if (code == RECORD_TYPE || code == UNION_TYPE)
92 if (is_userspace_type(fieldtype))
93 return true;
94
95 if (lookup_attribute("user", DECL_ATTRIBUTES(field)))
96 return true;
97 }
98 return false;
99}
100
101static void finish_type(void *event_data, void *data)
102{
103 tree type = (tree)event_data;
104
105 if (type == NULL_TREE || type == error_mark_node)
106 return;
107
108#if BUILDING_GCC_VERSION >= 5000
109 if (TREE_CODE(type) == ENUMERAL_TYPE)
110 return;
111#endif
112
113 if (TYPE_USERSPACE(type))
114 return;
115
116 if (is_userspace_type(type))
117 TYPE_USERSPACE(type) = 1;
118}
119
120static void initialize(tree var)
121{
122 basic_block bb;
123 gimple_stmt_iterator gsi;
124 tree initializer;
125 gimple init_stmt;
126 tree type;
127
128
129 bb = single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun));
130
131
132 for (gsi = gsi_start_bb(bb); !gsi_end_p(gsi); gsi_next(&gsi)) {
133 gimple stmt = gsi_stmt(gsi);
134 tree rhs1;
135
136
137 if (!gimple_assign_single_p(stmt))
138 continue;
139 rhs1 = gimple_assign_rhs1(stmt);
140#if BUILDING_GCC_VERSION >= 4007
141
142 if (TREE_CLOBBER_P(rhs1))
143 continue;
144#endif
145
146 if (gimple_get_lhs(stmt) != var)
147 continue;
148
149 if (TREE_CODE(rhs1) == CONSTRUCTOR)
150 return;
151 }
152
153
154 if (verbose)
155 inform(DECL_SOURCE_LOCATION(var),
156 "%s variable will be forcibly initialized",
157 (byref && TREE_ADDRESSABLE(var)) ? "byref"
158 : "userspace");
159
160
161 type = TREE_TYPE(var);
162 if (AGGREGATE_TYPE_P(type))
163 initializer = build_constructor(type, NULL);
164 else
165 initializer = fold_convert(type, integer_zero_node);
166
167
168 init_stmt = gimple_build_assign(var, initializer);
169 gsi = gsi_after_labels(single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
170 gsi_insert_before(&gsi, init_stmt, GSI_NEW_STMT);
171 update_stmt(init_stmt);
172}
173
174static unsigned int structleak_execute(void)
175{
176 basic_block bb;
177 unsigned int ret = 0;
178 tree var;
179 unsigned int i;
180
181
182 gcc_assert(single_succ_p(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
183 bb = single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun));
184 if (!single_pred_p(bb)) {
185 split_edge(single_succ_edge(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
186 gcc_assert(single_succ_p(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
187 }
188
189
190 FOR_EACH_LOCAL_DECL(cfun, i, var) {
191 tree type = TREE_TYPE(var);
192
193 gcc_assert(DECL_P(var));
194 if (!auto_var_in_fn_p(var, current_function_decl))
195 continue;
196
197
198 if (byref != BYREF_ALL && TREE_CODE(type) != RECORD_TYPE && TREE_CODE(type) != UNION_TYPE)
199 continue;
200
201
202 if (TYPE_USERSPACE(type) ||
203 (byref && TREE_ADDRESSABLE(var)))
204 initialize(var);
205 }
206
207 return ret;
208}
209
210#define PASS_NAME structleak
211#define NO_GATE
212#define PROPERTIES_REQUIRED PROP_cfg
213#define TODO_FLAGS_FINISH TODO_verify_il | TODO_verify_ssa | TODO_verify_stmts | TODO_dump_func | TODO_remove_unused_locals | TODO_update_ssa | TODO_ggc_collect | TODO_verify_flow
214#include "gcc-generate-gimple-pass.h"
215
216__visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version)
217{
218 int i;
219 const char * const plugin_name = plugin_info->base_name;
220 const int argc = plugin_info->argc;
221 const struct plugin_argument * const argv = plugin_info->argv;
222 bool enable = true;
223
224 PASS_INFO(structleak, "early_optimizations", 1, PASS_POS_INSERT_BEFORE);
225
226 if (!plugin_default_version_check(version, &gcc_version)) {
227 error(G_("incompatible gcc/plugin versions"));
228 return 1;
229 }
230
231 if (strncmp(lang_hooks.name, "GNU C", 5) && !strncmp(lang_hooks.name, "GNU C+", 6)) {
232 inform(UNKNOWN_LOCATION, G_("%s supports C only, not %s"), plugin_name, lang_hooks.name);
233 enable = false;
234 }
235
236 for (i = 0; i < argc; ++i) {
237 if (!strcmp(argv[i].key, "disable")) {
238 enable = false;
239 continue;
240 }
241 if (!strcmp(argv[i].key, "verbose")) {
242 verbose = true;
243 continue;
244 }
245 if (!strcmp(argv[i].key, "byref")) {
246 byref = BYREF_STRUCT;
247 continue;
248 }
249 if (!strcmp(argv[i].key, "byref-all")) {
250 byref = BYREF_ALL;
251 continue;
252 }
253 error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key);
254 }
255
256 register_callback(plugin_name, PLUGIN_INFO, NULL, &structleak_plugin_info);
257 if (enable) {
258 register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &structleak_pass_info);
259 register_callback(plugin_name, PLUGIN_FINISH_TYPE, finish_type, NULL);
260 }
261 register_callback(plugin_name, PLUGIN_ATTRIBUTES, register_attributes, NULL);
262
263 return 0;
264}
265
