Add sancov plugin

[cascardo/linux.git] / scripts / gcc-plugins / sancov_plugin.c

diff --git a/scripts/gcc-plugins/sancov_plugin.c b/scripts/gcc-plugins/sancov_plugin.c
new file mode 100644 (file)
index 0000000..aedd611
--- /dev/null
+++ b/scripts/gcc-plugins/sancov_plugin.c
@@ -0,0 +1,144 @@
+/*
+ * 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"
+
+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
+}
+
+int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version)
+{
+       int i;
+       struct register_pass_info sancov_plugin_pass_info;
+       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 = &gt_ggc_mx_tree_node,
+                       .pchw = &gt_pch_nx_tree_node
+               },
+               LAST_GGC_ROOT_TAB
+       };
+
+       /* BBs can be split afterwards?? */
+       sancov_plugin_pass_info.pass                            = make_sancov_pass();
+#if BUILDING_GCC_VERSION >= 4009
+       sancov_plugin_pass_info.reference_pass_name             = "asan";
+#else
+       sancov_plugin_pass_info.reference_pass_name             = "nrv";
+#endif
+       sancov_plugin_pass_info.ref_pass_instance_number        = 0;
+       sancov_plugin_pass_info.pos_op                          = PASS_POS_INSERT_BEFORE;
+
+       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_("unkown 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 *)&gt_ggc_r_gt_sancov);
+       register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &sancov_plugin_pass_info);
+#endif
+
+       return 0;
+}