1 | /* |
2 | * Copyright 2011-2016 by Emese Revfy <re.emese@gmail.com> |
3 | * Licensed under the GPL v2, or (at your option) v3 |
4 | * |
5 | * Homepage: |
6 | * https://github.com/ephox-gcc-plugins/sancov |
7 | * |
8 | * This plugin inserts a __sanitizer_cov_trace_pc() call at the start of basic blocks. |
9 | * It supports all gcc versions with plugin support (from gcc-4.5 on). |
10 | * It is based on the commit "Add fuzzing coverage support" by Dmitry Vyukov <dvyukov@google.com>. |
11 | * |
12 | * You can read about it more here: |
13 | * https://gcc.gnu.org/viewcvs/gcc?limit_changes=0&view=revision&revision=231296 |
14 | * https://lwn.net/Articles/674854/ |
15 | * https://github.com/google/syzkaller |
16 | * https://lwn.net/Articles/677764/ |
17 | * |
18 | * Usage: |
19 | * make run |
20 | */ |
21 | |
22 | #include "gcc-common.h" |
23 | |
24 | __visible int plugin_is_GPL_compatible; |
25 | |
26 | tree sancov_fndecl; |
27 | |
28 | static struct plugin_info sancov_plugin_info = { |
29 | .version = PLUGIN_VERSION, |
30 | .help = "sancov plugin\n" , |
31 | }; |
32 | |
33 | static unsigned int sancov_execute(void) |
34 | { |
35 | basic_block bb; |
36 | |
37 | /* Remove this line when this plugin and kcov will be in the kernel. |
38 | if (!strcmp(DECL_NAME_POINTER(current_function_decl), DECL_NAME_POINTER(sancov_fndecl))) |
39 | return 0; |
40 | */ |
41 | |
42 | FOR_EACH_BB_FN(bb, cfun) { |
43 | const_gimple stmt; |
44 | gcall *gcall; |
45 | gimple_stmt_iterator gsi = gsi_after_labels(bb); |
46 | |
47 | if (gsi_end_p(gsi)) |
48 | continue; |
49 | |
50 | stmt = gsi_stmt(gsi); |
51 | gcall = as_a_gcall(gimple_build_call(sancov_fndecl, 0)); |
52 | gimple_set_location(gcall, gimple_location(stmt)); |
53 | gsi_insert_before(&gsi, gcall, GSI_SAME_STMT); |
54 | } |
55 | return 0; |
56 | } |
57 | |
58 | #define PASS_NAME sancov |
59 | |
60 | #define NO_GATE |
61 | #define TODO_FLAGS_FINISH TODO_dump_func | TODO_verify_stmts | TODO_update_ssa_no_phi | TODO_verify_flow |
62 | |
63 | #include "gcc-generate-gimple-pass.h" |
64 | |
65 | static void sancov_start_unit(void __unused *gcc_data, void __unused *user_data) |
66 | { |
67 | tree leaf_attr, nothrow_attr; |
68 | tree BT_FN_VOID = build_function_type_list(void_type_node, NULL_TREE); |
69 | |
70 | sancov_fndecl = build_fn_decl("__sanitizer_cov_trace_pc" , BT_FN_VOID); |
71 | |
72 | DECL_ASSEMBLER_NAME(sancov_fndecl); |
73 | TREE_PUBLIC(sancov_fndecl) = 1; |
74 | DECL_EXTERNAL(sancov_fndecl) = 1; |
75 | DECL_ARTIFICIAL(sancov_fndecl) = 1; |
76 | DECL_PRESERVE_P(sancov_fndecl) = 1; |
77 | DECL_UNINLINABLE(sancov_fndecl) = 1; |
78 | TREE_USED(sancov_fndecl) = 1; |
79 | |
80 | nothrow_attr = tree_cons(get_identifier("nothrow" ), NULL, NULL); |
81 | decl_attributes(&sancov_fndecl, nothrow_attr, 0); |
82 | gcc_assert(TREE_NOTHROW(sancov_fndecl)); |
83 | leaf_attr = tree_cons(get_identifier("leaf" ), NULL, NULL); |
84 | decl_attributes(&sancov_fndecl, leaf_attr, 0); |
85 | } |
86 | |
87 | __visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version) |
88 | { |
89 | int i; |
90 | const char * const plugin_name = plugin_info->base_name; |
91 | const int argc = plugin_info->argc; |
92 | const struct plugin_argument * const argv = plugin_info->argv; |
93 | bool enable = true; |
94 | |
95 | static const struct ggc_root_tab gt_ggc_r_gt_sancov[] = { |
96 | { |
97 | .base = &sancov_fndecl, |
98 | .nelt = 1, |
99 | .stride = sizeof(sancov_fndecl), |
100 | .cb = >_ggc_mx_tree_node, |
101 | .pchw = >_pch_nx_tree_node |
102 | }, |
103 | LAST_GGC_ROOT_TAB |
104 | }; |
105 | |
106 | /* BBs can be split afterwards?? */ |
107 | PASS_INFO(sancov, "asan" , 0, PASS_POS_INSERT_BEFORE); |
108 | |
109 | if (!plugin_default_version_check(version, &gcc_version)) { |
110 | error(G_("incompatible gcc/plugin versions" )); |
111 | return 1; |
112 | } |
113 | |
114 | for (i = 0; i < argc; ++i) { |
115 | if (!strcmp(argv[i].key, "no-sancov" )) { |
116 | enable = false; |
117 | continue; |
118 | } |
119 | error(G_("unknown option '-fplugin-arg-%s-%s'" ), plugin_name, argv[i].key); |
120 | } |
121 | |
122 | register_callback(plugin_name, PLUGIN_INFO, NULL, &sancov_plugin_info); |
123 | |
124 | if (!enable) |
125 | return 0; |
126 | |
127 | #if BUILDING_GCC_VERSION < 6000 |
128 | register_callback(plugin_name, PLUGIN_START_UNIT, &sancov_start_unit, NULL); |
129 | register_callback(plugin_name, PLUGIN_REGISTER_GGC_ROOTS, NULL, (void *)>_ggc_r_gt_sancov); |
130 | register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &sancov_pass_info); |
131 | #endif |
132 | |
133 | return 0; |
134 | } |
135 | |