use-after-scope: handle writes to a poisoned variable

2017-01-23  Martin Liska  <mliska@suse.cz>

	* gcc.dg/asan/use-after-scope-10.c: New test.
	* gcc.dg/asan/use-after-scope-11.c: New test.
	* g++.dg/asan/use-after-scope-5.C: New test.
2017-01-23  Jakub Jelinek  <jakub@redhat.com>
	    Martin Liska  <mliska@suse.cz>

	* asan.h: Define ASAN_USE_AFTER_SCOPE_ATTRIBUTE.
	* asan.c (asan_expand_poison_ifn): Support stores and use
	appropriate ASAN report function.
	* internal-fn.c (expand_ASAN_POISON_USE): New function.
	* internal-fn.def (ASAN_POISON_USE): Declare.
	* tree-into-ssa.c (maybe_add_asan_poison_write): New function.
	(maybe_register_def): Create ASAN_POISON_USE when sanitizing.
	* tree-ssa-dce.c (eliminate_unnecessary_stmts): Remove
	ASAN_POISON calls w/o LHS.
	* tree-ssa.c (execute_update_addresses_taken): Create clobber
	for ASAN_MARK (UNPOISON, &x, ...) in order to prevent usage of a LHS
	from ASAN_MARK (POISON, &x, ...) coming to a PHI node.
	* gimplify.c (asan_poison_variables): Add attribute
	use_after_scope_memory to variables that really needs to live
	in memory.
	* tree-ssa.c (is_asan_mark_p): Do not rewrite into SSA when
	having the attribute.

From-SVN: r244793