[google] ThreadSanitizer instrumentation pass (issue5303083)

The patch is for google/main branch.
ThreadSanitizer is a data race detector for C/C++ programs.
http://code.google.com/p/data-race-test/wiki/ThreadSanitizer

The tool consists of two parts:
instrumentation module (this file) and a run-time library.
The instrumentation module mainintains shadow call stacks
and intercepts interesting memory accesses.
The instrumentation is enabled with -ftsan flag.

Instrumentation for shadow stack maintainance is as follows:
void somefunc ()
{
  __tsan_shadow_stack [-1] = __builtin_return_address (0);
  __tsan_shadow_stack++;
  // function body
  __tsan_shadow_stack--;
}

Interception for memory access interception is as follows:
*addr = 1;
__tsan_handle_mop (addr, flags);
where flags are (is_sblock | (is_store << 1) | ((sizeof (*addr) - 1) << 2).
is_sblock is used merely for optimization purposes and can always
be set to 1, see comments in instrument_mops function.

Ignore files can be used to selectively non instrument some functions.
Ignore file is specified with -ftsan-ignore=filename flag.
There are 3 types of ignores: (1) do not instrument memory accesses
in the function, (2) do not create sblocks in the function
and (3) recursively ignore memory accesses in the function.
That last ignore type requires additional instrumentation of the form:
void somefunc ()
{
  __tsan_thread_ignore++;
  // function body
  __tsan_thread_ignore--;
}

The run-time library provides __tsan_handle_mop function,
definitions of __tsan_shadow_stack and __tsan_thread_ignore variables,
and intercepts synchronization related functions.

2011-10-28   Dmitriy Vyukov  <dvyukov@google.com>

	* gcc/doc/invoke.texi:
	* gcc/tree-tsan.c (enum tsan_ignore_e):
	(enum bb_state_e):
	(struct bb_data_t):
	(struct mop_desc_t):
	(struct tsan_ignore_desc_t):
	(lookup_name):
	(shadow_stack_def):
	(thread_ignore_def):
	(rtl_mop_def):
	(ignore_append):
	(ignore_match):
	(ignore_load):
	(tsan_ignore):
	(decl_name):
	(build_stack_op):
	(build_rec_ignore_op):
	(build_stack_assign):
	(instr_mop):
	(instr_vptr_store):
	(instr_func):
	(set_location):
	(is_dtor_vptr_store):
	(is_vtbl_read):
	(is_load_of_const):
	(handle_expr):
	(handle_gimple):
	(instrument_bblock):
	(instrument_mops):
	(instrument_function):
	(tsan_pass):
	(tsan_gate):
	* gcc/tree-pass.h:
	* gcc/testsuite/gcc.dg/tsan-ignore.ignore:
	* gcc/testsuite/gcc.dg/tsan.h (__tsan_init):
	(__tsan_expect_mop):
	(__tsan_handle_mop):
	* gcc/testsuite/gcc.dg/tsan-ignore.c (foo):
	(int bar):
	(int baz):
	(int bla):
	(int xxx):
	(main):
	* gcc/testsuite/gcc.dg/tsan-ignore.h (in_tsan_ignore_header):
	* gcc/testsuite/gcc.dg/tsan-stack.c (foobar):
	* gcc/testsuite/gcc.dg/tsan-mop.c:
	* gcc/common.opt:
	* gcc/Makefile.in:
	* gcc/passes.c:

--
This patch is available for review at http://codereview.appspot.com/5303083

[google] ThreadSanitizer instrumentation pass (issue5303083)

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