ASAN: Implement dynamic allocas/VLAs sanitization.

ASAN: Implement dynamic allocas/VLAs sanitization.

gcc/
	* asan.c: Include gimple-fold.h.
	(get_last_alloca_addr): New function.
	(handle_builtin_stackrestore): Likewise.
	(handle_builtin_alloca): Likewise.
	(asan_emit_allocas_unpoison): Likewise.
	(get_mem_refs_of_builtin_call): Add new parameter, remove const
	quallifier from first paramerer. Handle BUILT_IN_ALLOCA,
	BUILT_IN_ALLOCA_WITH_ALIGN and BUILT_IN_STACK_RESTORE builtins.
	(instrument_builtin_call): Pass gimple iterator to
	get_mem_refs_of_builtin_call.
	(last_alloca_addr): New global.
	* asan.h (asan_emit_allocas_unpoison): Declare.
	* builtins.c (expand_asan_emit_allocas_unpoison): New function.
	(expand_builtin): Handle BUILT_IN_ASAN_ALLOCAS_UNPOISON.
	* cfgexpand.c (expand_used_vars): Call asan_emit_allocas_unpoison
	if function calls alloca.
	* gimple-fold.c (replace_call_with_value): Remove static keyword.
	* gimple-fold.h (replace_call_with_value): Declare.
	* internal-fn.c: Include asan.h.
	* sanitizer.def (BUILT_IN_ASAN_ALLOCA_POISON,
	BUILT_IN_ASAN_ALLOCAS_UNPOISON): New builtins.

gcc/testsuite/
	* c-c++-common/asan/alloca_big_alignment.c: New test.
	* c-c++-common/asan/alloca_detect_custom_size.c: Likewise.
	* c-c++-common/asan/alloca_instruments_all_paddings.c: Likewise.
	* c-c++-common/asan/alloca_loop_unpoisoning.c: Likewise.
	* c-c++-common/asan/alloca_overflow_partial.c: Likewise.
	* c-c++-common/asan/alloca_overflow_right.c: Likewise.
	* c-c++-common/asan/alloca_safe_access.c: Likewise.
	* c-c++-common/asan/alloca_underflow_left.c: Likewise.

From-SVN: r250031