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/*
* 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
* https://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 = PLUGIN_VERSION,
.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));
leaf_attr = tree_cons(get_identifier("leaf"), NULL, NULL);
decl_attributes(&sancov_fndecl, leaf_attr, 0);
}
__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?? */
PASS_INFO(sancov, "asan", 0, 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_("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;
}
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