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da7389ac6c
This explicitly exports symbols that gcc expects from plugins. Based on code from Emese Revfy. Signed-off-by: Kees Cook <keescook@chromium.org>
144 lines
4.1 KiB
C
144 lines
4.1 KiB
C
/*
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* Copyright 2011-2016 by Emese Revfy <re.emese@gmail.com>
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* Licensed under the GPL v2, or (at your option) v3
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*
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* Homepage:
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* https://github.com/ephox-gcc-plugins/sancov
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*
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* This plugin inserts a __sanitizer_cov_trace_pc() call at the start of basic blocks.
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* It supports all gcc versions with plugin support (from gcc-4.5 on).
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* It is based on the commit "Add fuzzing coverage support" by Dmitry Vyukov <dvyukov@google.com>.
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*
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* You can read about it more here:
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* https://gcc.gnu.org/viewcvs/gcc?limit_changes=0&view=revision&revision=231296
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* http://lwn.net/Articles/674854/
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* https://github.com/google/syzkaller
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* https://lwn.net/Articles/677764/
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*
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* Usage:
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* make run
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*/
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#include "gcc-common.h"
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__visible int plugin_is_GPL_compatible;
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tree sancov_fndecl;
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static struct plugin_info sancov_plugin_info = {
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.version = "20160402",
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.help = "sancov plugin\n",
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};
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static unsigned int sancov_execute(void)
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{
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basic_block bb;
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/* Remove this line when this plugin and kcov will be in the kernel.
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if (!strcmp(DECL_NAME_POINTER(current_function_decl), DECL_NAME_POINTER(sancov_fndecl)))
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return 0;
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*/
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FOR_EACH_BB_FN(bb, cfun) {
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const_gimple stmt;
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gcall *gcall;
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gimple_stmt_iterator gsi = gsi_after_labels(bb);
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if (gsi_end_p(gsi))
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continue;
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stmt = gsi_stmt(gsi);
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gcall = as_a_gcall(gimple_build_call(sancov_fndecl, 0));
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gimple_set_location(gcall, gimple_location(stmt));
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gsi_insert_before(&gsi, gcall, GSI_SAME_STMT);
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}
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return 0;
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}
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#define PASS_NAME sancov
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#define NO_GATE
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#define TODO_FLAGS_FINISH TODO_dump_func | TODO_verify_stmts | TODO_update_ssa_no_phi | TODO_verify_flow
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#include "gcc-generate-gimple-pass.h"
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static void sancov_start_unit(void __unused *gcc_data, void __unused *user_data)
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{
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tree leaf_attr, nothrow_attr;
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tree BT_FN_VOID = build_function_type_list(void_type_node, NULL_TREE);
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sancov_fndecl = build_fn_decl("__sanitizer_cov_trace_pc", BT_FN_VOID);
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DECL_ASSEMBLER_NAME(sancov_fndecl);
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TREE_PUBLIC(sancov_fndecl) = 1;
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DECL_EXTERNAL(sancov_fndecl) = 1;
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DECL_ARTIFICIAL(sancov_fndecl) = 1;
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DECL_PRESERVE_P(sancov_fndecl) = 1;
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DECL_UNINLINABLE(sancov_fndecl) = 1;
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TREE_USED(sancov_fndecl) = 1;
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nothrow_attr = tree_cons(get_identifier("nothrow"), NULL, NULL);
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decl_attributes(&sancov_fndecl, nothrow_attr, 0);
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gcc_assert(TREE_NOTHROW(sancov_fndecl));
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#if BUILDING_GCC_VERSION > 4005
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leaf_attr = tree_cons(get_identifier("leaf"), NULL, NULL);
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decl_attributes(&sancov_fndecl, leaf_attr, 0);
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#endif
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}
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__visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version)
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{
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int i;
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struct register_pass_info sancov_plugin_pass_info;
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const char * const plugin_name = plugin_info->base_name;
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const int argc = plugin_info->argc;
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const struct plugin_argument * const argv = plugin_info->argv;
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bool enable = true;
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static const struct ggc_root_tab gt_ggc_r_gt_sancov[] = {
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{
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.base = &sancov_fndecl,
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.nelt = 1,
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.stride = sizeof(sancov_fndecl),
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.cb = >_ggc_mx_tree_node,
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.pchw = >_pch_nx_tree_node
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},
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LAST_GGC_ROOT_TAB
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};
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/* BBs can be split afterwards?? */
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sancov_plugin_pass_info.pass = make_sancov_pass();
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#if BUILDING_GCC_VERSION >= 4009
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sancov_plugin_pass_info.reference_pass_name = "asan";
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#else
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sancov_plugin_pass_info.reference_pass_name = "nrv";
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#endif
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sancov_plugin_pass_info.ref_pass_instance_number = 0;
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sancov_plugin_pass_info.pos_op = PASS_POS_INSERT_BEFORE;
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if (!plugin_default_version_check(version, &gcc_version)) {
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error(G_("incompatible gcc/plugin versions"));
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return 1;
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}
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for (i = 0; i < argc; ++i) {
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if (!strcmp(argv[i].key, "no-sancov")) {
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enable = false;
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continue;
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}
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error(G_("unkown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key);
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}
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register_callback(plugin_name, PLUGIN_INFO, NULL, &sancov_plugin_info);
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if (!enable)
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return 0;
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#if BUILDING_GCC_VERSION < 6000
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register_callback(plugin_name, PLUGIN_START_UNIT, &sancov_start_unit, NULL);
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register_callback(plugin_name, PLUGIN_REGISTER_GGC_ROOTS, NULL, (void *)>_ggc_r_gt_sancov);
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register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &sancov_plugin_pass_info);
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#endif
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return 0;
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}
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