/* * Copyright 2011-2016 by Emese Revfy <re.emese@gmail.com> * Licensed under the GPL v2, or (at your option) v3 * * Homepage: * https://github.com/ephox-gcc-plugins/sancov * * This plugin inserts a __sanitizer_cov_trace_pc() call at the start of basic blocks. * It supports all gcc versions with plugin support (from gcc-4.5 on). * It is based on the commit "Add fuzzing coverage support" by Dmitry Vyukov <dvyukov@google.com>. * * You can read about it more here: * https://gcc.gnu.org/viewcvs/gcc?limit_changes=0&view=revision&revision=231296 * http://lwn.net/Articles/674854/ * https://github.com/google/syzkaller * https://lwn.net/Articles/677764/ * * Usage: * make run */ #include "gcc-common.h" __visible int plugin_is_GPL_compatible; tree sancov_fndecl; static struct plugin_info sancov_plugin_info = { .version = "20160402", .help = "sancov plugin\n", }; static unsigned int sancov_execute(void) { basic_block bb; /* Remove this line when this plugin and kcov will be in the kernel. if (!strcmp(DECL_NAME_POINTER(current_function_decl), DECL_NAME_POINTER(sancov_fndecl))) return 0; */ FOR_EACH_BB_FN(bb, cfun) { const_gimple stmt; gcall *gcall; gimple_stmt_iterator gsi = gsi_after_labels(bb); if (gsi_end_p(gsi)) continue; stmt = gsi_stmt(gsi); gcall = as_a_gcall(gimple_build_call(sancov_fndecl, 0)); gimple_set_location(gcall, gimple_location(stmt)); gsi_insert_before(&gsi, gcall, GSI_SAME_STMT); } return 0; } #define PASS_NAME sancov #define NO_GATE #define TODO_FLAGS_FINISH TODO_dump_func | TODO_verify_stmts | TODO_update_ssa_no_phi | TODO_verify_flow #include "gcc-generate-gimple-pass.h" static void sancov_start_unit(void __unused *gcc_data, void __unused *user_data) { tree leaf_attr, nothrow_attr; tree BT_FN_VOID = build_function_type_list(void_type_node, NULL_TREE); sancov_fndecl = build_fn_decl("__sanitizer_cov_trace_pc", BT_FN_VOID); DECL_ASSEMBLER_NAME(sancov_fndecl); TREE_PUBLIC(sancov_fndecl) = 1; DECL_EXTERNAL(sancov_fndecl) = 1; DECL_ARTIFICIAL(sancov_fndecl) = 1; DECL_PRESERVE_P(sancov_fndecl) = 1; DECL_UNINLINABLE(sancov_fndecl) = 1; TREE_USED(sancov_fndecl) = 1; nothrow_attr = tree_cons(get_identifier("nothrow"), NULL, NULL); decl_attributes(&sancov_fndecl, nothrow_attr, 0); gcc_assert(TREE_NOTHROW(sancov_fndecl)); #if BUILDING_GCC_VERSION > 4005 leaf_attr = tree_cons(get_identifier("leaf"), NULL, NULL); decl_attributes(&sancov_fndecl, leaf_attr, 0); #endif } __visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version) { int i; const char * const plugin_name = plugin_info->base_name; const int argc = plugin_info->argc; const struct plugin_argument * const argv = plugin_info->argv; bool enable = true; static const struct ggc_root_tab gt_ggc_r_gt_sancov[] = { { .base = &sancov_fndecl, .nelt = 1, .stride = sizeof(sancov_fndecl), .cb = >_ggc_mx_tree_node, .pchw = >_pch_nx_tree_node }, LAST_GGC_ROOT_TAB }; /* BBs can be split afterwards?? */ #if BUILDING_GCC_VERSION >= 4009 PASS_INFO(sancov, "asan", 0, PASS_POS_INSERT_BEFORE); #else PASS_INFO(sancov, "nrv", 1, PASS_POS_INSERT_BEFORE); #endif if (!plugin_default_version_check(version, &gcc_version)) { error(G_("incompatible gcc/plugin versions")); return 1; } for (i = 0; i < argc; ++i) { if (!strcmp(argv[i].key, "no-sancov")) { enable = false; continue; } error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key); } register_callback(plugin_name, PLUGIN_INFO, NULL, &sancov_plugin_info); if (!enable) return 0; #if BUILDING_GCC_VERSION < 6000 register_callback(plugin_name, PLUGIN_START_UNIT, &sancov_start_unit, NULL); register_callback(plugin_name, PLUGIN_REGISTER_GGC_ROOTS, NULL, (void *)>_ggc_r_gt_sancov); register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &sancov_pass_info); #endif return 0; }