[thirdparty/gcc.git] / gcc / tsan.c

/* GCC instrumentation plugin for ThreadSanitizer.
   Copyright (C) 2011, 2012 Free Software Foundation, Inc.
   Contributed by Dmitry Vyukov <dvyukov@google.com>

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */


#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tree.h"
#include "intl.h"
#include "tm.h"
#include "basic-block.h"
#include "gimple.h"
#include "function.h"
#include "tree-flow.h"
#include "tree-pass.h"
#include "tree-iterator.h"
#include "langhooks.h"
#include "output.h"
#include "options.h"
#include "target.h"
#include "cgraph.h"
#include "diagnostic.h"

/* Number of instrumented memory accesses in the current function.  */

/* Builds the following decl
   void __tsan_read/writeX (void *addr);  */

static tree
get_memory_access_decl (bool is_write, unsigned size)
{
  enum built_in_function fcode;

  if (size <= 1)
    fcode = is_write ? BUILT_IN_TSAN_WRITE_1
		     : BUILT_IN_TSAN_READ_1;
  else if (size <= 3)
    fcode = is_write ? BUILT_IN_TSAN_WRITE_2
		     : BUILT_IN_TSAN_READ_2;
  else if (size <= 7)
    fcode = is_write ? BUILT_IN_TSAN_WRITE_4
		     : BUILT_IN_TSAN_READ_4;
  else if (size <= 15)
    fcode = is_write ? BUILT_IN_TSAN_WRITE_8
		     : BUILT_IN_TSAN_READ_8;
  else
    fcode = is_write ? BUILT_IN_TSAN_WRITE_16
		     : BUILT_IN_TSAN_READ_16;

  return builtin_decl_implicit (fcode);
}

/* Check as to whether EXPR refers to a store to vptr.  */

static tree
is_vptr_store (gimple stmt, tree expr, bool is_write)
{
  if (is_write == true
      && gimple_assign_single_p (stmt)
      && TREE_CODE (expr) == COMPONENT_REF)
    {
      tree field = TREE_OPERAND (expr, 1);
      if (TREE_CODE (field) == FIELD_DECL
	  && DECL_VIRTUAL_P (field))
	return gimple_assign_rhs1 (stmt);
    }
  return NULL;
}

/* Checks as to whether EXPR refers to constant var/field/param.
   Don't bother to instrument them.  */

static bool
is_load_of_const_p (tree expr, bool is_write)
{
  if (is_write)
    return false;
  if (TREE_CODE (expr) == COMPONENT_REF)
    expr = TREE_OPERAND (expr, 1);
  if (TREE_CODE (expr) == VAR_DECL
      || TREE_CODE (expr) == PARM_DECL
      || TREE_CODE (expr) == FIELD_DECL)
    {
      if (TREE_READONLY (expr))
	return true;
    }
  return false;
}

/* Instruments EXPR if needed. If any instrumentation is inserted,
   return true.  */

static bool
instrument_expr (gimple_stmt_iterator gsi, tree expr, bool is_write)
{
  enum tree_code tcode;
  tree base, rhs, expr_type, expr_ptr, builtin_decl;
  basic_block bb;
  HOST_WIDE_INT size;
  gimple stmt, g;
  location_t loc;

  base = get_base_address (expr);
  if (base == NULL_TREE
      || TREE_CODE (base) == SSA_NAME
      || TREE_CODE (base) == STRING_CST)
    return false;

  tcode = TREE_CODE (expr);

  /* Below are things we do not instrument
     (no possibility of races or not implemented yet).  */
  if (/* Compiler-emitted artificial variables.  */
      (DECL_P (expr) && DECL_ARTIFICIAL (expr))
      /* The var does not live in memory -> no possibility of races.  */
      || (tcode == VAR_DECL
	  && !TREE_ADDRESSABLE (expr)
	  && TREE_STATIC (expr) == 0)
      /* Not implemented.  */
      || TREE_CODE (TREE_TYPE (expr)) == RECORD_TYPE
      /* Not implemented.  */
      || tcode == CONSTRUCTOR
      /* Not implemented.  */
      || tcode == PARM_DECL
      /* Load of a const variable/parameter/field.  */
      || is_load_of_const_p (expr, is_write))
    return false;

  size = int_size_in_bytes (TREE_TYPE (expr));
  if (size == -1)
    return false;

  /* For now just avoid instrumenting bit field acceses.
     TODO: handle bit-fields as if touching the whole field.  */
  HOST_WIDE_INT bitsize, bitpos;
  tree offset;
  enum machine_mode mode;
  int volatilep = 0, unsignedp = 0;
  get_inner_reference (expr, &bitsize, &bitpos, &offset,
		       &mode, &unsignedp, &volatilep, false);
  if (bitpos % (size * BITS_PER_UNIT)
      || bitsize != size * BITS_PER_UNIT)
    return false;

  /* TODO: handle other case: ARRAY_RANGE_REF.  */
  if (tcode != ARRAY_REF
      && tcode != VAR_DECL
      && tcode != COMPONENT_REF
      && tcode != INDIRECT_REF
      && tcode != MEM_REF)
    return false;

  stmt = gsi_stmt (gsi);
  loc = gimple_location (stmt);
  rhs = is_vptr_store (stmt, expr, is_write);
  gcc_checking_assert (rhs != NULL || is_gimple_addressable (expr));
  expr_ptr = build_fold_addr_expr (unshare_expr (expr));
  if (rhs == NULL)
    {
      expr_type = TREE_TYPE (expr);
      while (TREE_CODE (expr_type) == ARRAY_TYPE)
	expr_type = TREE_TYPE (expr_type);
      size = int_size_in_bytes (expr_type);
      g = gimple_build_call (get_memory_access_decl (is_write, size),
			     1, expr_ptr);
    }
  else
    {
      builtin_decl = builtin_decl_implicit (BUILT_IN_TSAN_VPTR_UPDATE);
      g = gimple_build_call (builtin_decl, 1, expr_ptr);
    }
  gimple_set_location (g, loc);
  /* Instrumentation for assignment of a function result
     must be inserted after the call.  Instrumentation for
     reads of function arguments must be inserted before the call.
     That's because the call can contain synchronization.  */
  if (is_gimple_call (stmt) && is_write)
    {
      /* If the call can throw, it must be the last stmt in
	 a basic block, so the instrumented stmts need to be
	 inserted in successor bbs.  */
      if (is_ctrl_altering_stmt (stmt))
	{
	  edge e;

	  bb = gsi_bb (gsi);
	  e = find_fallthru_edge (bb->succs);
	  if (e)
	    gsi_insert_seq_on_edge_immediate (e, g);
	}
      else
	gsi_insert_after (&gsi, g, GSI_NEW_STMT);
    }
  else
    gsi_insert_before (&gsi, g, GSI_SAME_STMT);

  return true;
}

/* Instruments the gimple pointed to by GSI. Return
   true if func entry/exit should be instrumented.  */

static bool
instrument_gimple (gimple_stmt_iterator gsi)
{
  gimple stmt;
  tree rhs, lhs;
  bool instrumented = false;

  stmt = gsi_stmt (gsi);
  if (is_gimple_call (stmt)
      && (gimple_call_fndecl (stmt)
	  != builtin_decl_implicit (BUILT_IN_TSAN_INIT)))
    return true;
  else if (is_gimple_assign (stmt)
	   && !gimple_clobber_p (stmt))
    {
      if (gimple_store_p (stmt))
	{
	  lhs = gimple_assign_lhs (stmt);
	  instrumented = instrument_expr (gsi, lhs, true);
	}
      if (gimple_assign_load_p (stmt))
	{
	  rhs = gimple_assign_rhs1 (stmt);
	  instrumented = instrument_expr (gsi, rhs, false);
	}
    }
  return instrumented;
}

/* Instruments all interesting memory accesses in the current function.
   Return true if func entry/exit should be instrumented.  */

static bool
instrument_memory_accesses (void)
{
  basic_block bb;
  gimple_stmt_iterator gsi;
  bool fentry_exit_instrument = false;

  FOR_EACH_BB (bb)
    for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
      fentry_exit_instrument |= instrument_gimple (gsi);
  return fentry_exit_instrument;
}

/* Instruments function entry.  */

static void
instrument_func_entry (void)
{
  basic_block succ_bb;
  gimple_stmt_iterator gsi;
  tree ret_addr, builtin_decl;
  gimple g;

  succ_bb = single_succ (ENTRY_BLOCK_PTR);
  gsi = gsi_after_labels (succ_bb);

  builtin_decl = builtin_decl_implicit (BUILT_IN_RETURN_ADDRESS);
  g = gimple_build_call (builtin_decl, 1, integer_zero_node);
  ret_addr = make_ssa_name (ptr_type_node, NULL);
  gimple_call_set_lhs (g, ret_addr);
  gimple_set_location (g, cfun->function_start_locus);
  gsi_insert_before (&gsi, g, GSI_SAME_STMT);

  builtin_decl =  builtin_decl_implicit (BUILT_IN_TSAN_FUNC_ENTRY);
  g = gimple_build_call (builtin_decl, 1, ret_addr);
  gimple_set_location (g, cfun->function_start_locus);
  gsi_insert_before (&gsi, g, GSI_SAME_STMT);
}

/* Instruments function exits.  */

static void
instrument_func_exit (void)
{
  location_t loc;
  basic_block exit_bb;
  gimple_stmt_iterator gsi;
  gimple stmt, g;
  tree builtin_decl;
  edge e;
  edge_iterator ei;

  /* Find all function exits.  */
  exit_bb = EXIT_BLOCK_PTR;
  FOR_EACH_EDGE (e, ei, exit_bb->preds)
    {
      gsi = gsi_last_bb (e->src);
      stmt = gsi_stmt (gsi);
      gcc_assert (gimple_code (stmt) == GIMPLE_RETURN);
      loc = gimple_location (stmt);
      builtin_decl = builtin_decl_implicit (BUILT_IN_TSAN_FUNC_EXIT);
      g = gimple_build_call (builtin_decl, 0);
      gimple_set_location (g, loc);
      gsi_insert_before (&gsi, g, GSI_SAME_STMT);
    }
}

/* ThreadSanitizer instrumentation pass.  */

static unsigned
tsan_pass (void)
{
  if (instrument_memory_accesses ())
    {
      instrument_func_entry ();
      instrument_func_exit ();
    }
  return 0;
}

/* The pass's gate.  */

static bool
tsan_gate (void)
{
  return flag_tsan != 0
	 && builtin_decl_implicit_p (BUILT_IN_TSAN_INIT);
}

/* Inserts __tsan_init () into the list of CTORs.  */

void
tsan_finish_file (void)
{
  tree ctor_statements;
  tree init_decl;

  ctor_statements = NULL_TREE;
  init_decl = builtin_decl_implicit (BUILT_IN_TSAN_INIT);
  append_to_statement_list (build_call_expr (init_decl, 0),
			    &ctor_statements);
  cgraph_build_static_cdtor ('I', ctor_statements,
			     MAX_RESERVED_INIT_PRIORITY - 1);
}

/* The pass descriptor.  */

struct gimple_opt_pass pass_tsan =
{
 {
  GIMPLE_PASS,
  "tsan",				/* name  */
  OPTGROUP_NONE,			/* optinfo_flags */
  tsan_gate,				/* gate  */
  tsan_pass,				/* execute  */
  NULL,					/* sub  */
  NULL,					/* next  */
  0,					/* static_pass_number  */
  TV_NONE,				/* tv_id  */
  PROP_ssa | PROP_cfg,			/* properties_required  */
  0,					/* properties_provided  */
  0,					/* properties_destroyed  */
  0,					/* todo_flags_start  */
  TODO_verify_all | TODO_update_ssa	/* todo_flags_finish  */
 }
};

static bool
tsan_gate_O0 (void)
{
  return flag_tsan != 0 && !optimize
	 && builtin_decl_implicit_p (BUILT_IN_TSAN_INIT);
}

struct gimple_opt_pass pass_tsan_O0 =
{
 {
  GIMPLE_PASS,
  "tsan0",				/* name  */
  OPTGROUP_NONE,			/* optinfo_flags */
  tsan_gate_O0,				/* gate  */
  tsan_pass,				/* execute  */
  NULL,					/* sub  */
  NULL,					/* next  */
  0,					/* static_pass_number  */
  TV_NONE,				/* tv_id  */
  PROP_ssa | PROP_cfg,			/* properties_required  */
  0,					/* properties_provided  */
  0,					/* properties_destroyed  */
  0,					/* todo_flags_start  */
  TODO_verify_all | TODO_update_ssa	/* todo_flags_finish  */
 }
};
Commit	Line	Data
32b4b7f5 DV	1	/* GCC instrumentation plugin for ThreadSanitizer.
	2	Copyright (C) 2011, 2012 Free Software Foundation, Inc.
	3	Contributed by Dmitry Vyukov <dvyukov@google.com>
	4
	5	This file is part of GCC.
	6
	7	GCC is free software; you can redistribute it and/or modify it under
	8	the terms of the GNU General Public License as published by the Free
	9	Software Foundation; either version 3, or (at your option) any later
	10	version.
	11
	12	GCC is distributed in the hope that it will be useful, but WITHOUT ANY
	13	WARRANTY; without even the implied warranty of MERCHANTABILITY or
	14	FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	15	for more details.
	16
	17	You should have received a copy of the GNU General Public License
	18	along with GCC; see the file COPYING3. If not see
	19	<http://www.gnu.org/licenses/>. */
	20
	21
	22	#include "config.h"
	23	#include "system.h"
	24	#include "coretypes.h"
	25	#include "tree.h"
	26	#include "intl.h"
	27	#include "tm.h"
	28	#include "basic-block.h"
	29	#include "gimple.h"
	30	#include "function.h"
	31	#include "tree-flow.h"
	32	#include "tree-pass.h"
	33	#include "tree-iterator.h"
	34	#include "langhooks.h"
	35	#include "output.h"
	36	#include "options.h"
	37	#include "target.h"
	38	#include "cgraph.h"
	39	#include "diagnostic.h"
	40
	41	/* Number of instrumented memory accesses in the current function. */
	42
	43	/* Builds the following decl
	44	void __tsan_read/writeX (void addr); /
	45
	46	static tree
	47	get_memory_access_decl (bool is_write, unsigned size)
	48	{
	49	enum built_in_function fcode;
	50
	51	if (size <= 1)
	52	fcode = is_write ? BUILT_IN_TSAN_WRITE_1
	53	: BUILT_IN_TSAN_READ_1;
	54	else if (size <= 3)
	55	fcode = is_write ? BUILT_IN_TSAN_WRITE_2
	56	: BUILT_IN_TSAN_READ_2;
	57	else if (size <= 7)
	58	fcode = is_write ? BUILT_IN_TSAN_WRITE_4
	59	: BUILT_IN_TSAN_READ_4;
	60	else if (size <= 15)
	61	fcode = is_write ? BUILT_IN_TSAN_WRITE_8
	62	: BUILT_IN_TSAN_READ_8;
	63	else
	64	fcode = is_write ? BUILT_IN_TSAN_WRITE_16
65	: BUILT_IN_TSAN_READ_16;
66
67	return builtin_decl_implicit (fcode);
68	}
69
70	/* Check as to whether EXPR refers to a store to vptr. */
71
72	static tree
73	is_vptr_store (gimple stmt, tree expr, bool is_write)
74	{
75	if (is_write == true
76	&& gimple_assign_single_p (stmt)
77	&& TREE_CODE (expr) == COMPONENT_REF)
78	{
79	tree field = TREE_OPERAND (expr, 1);
80	if (TREE_CODE (field) == FIELD_DECL
81	&& DECL_VIRTUAL_P (field))
82	return gimple_assign_rhs1 (stmt);
83	}
84	return NULL;
85	}
86
87	/* Checks as to whether EXPR refers to constant var/field/param.
88	Don't bother to instrument them. */
89
90	static bool
91	is_load_of_const_p (tree expr, bool is_write)
92	{
93	if (is_write)
94	return false;
95	if (TREE_CODE (expr) == COMPONENT_REF)
96	expr = TREE_OPERAND (expr, 1);
97	if (TREE_CODE (expr) == VAR_DECL
98	\|\| TREE_CODE (expr) == PARM_DECL
99	\|\| TREE_CODE (expr) == FIELD_DECL)
100	{
101	if (TREE_READONLY (expr))
102	return true;
103	}
104	return false;
105	}
106
107	/* Instruments EXPR if needed. If any instrumentation is inserted,
8ddf5c28	108	return true. */
32b4b7f5 DV	109
	110	static bool
	111	instrument_expr (gimple_stmt_iterator gsi, tree expr, bool is_write)
	112	{
	113	enum tree_code tcode;
	114	tree base, rhs, expr_type, expr_ptr, builtin_decl;
	115	basic_block bb;
	116	HOST_WIDE_INT size;
	117	gimple stmt, g;
	118	location_t loc;
	119
	120	base = get_base_address (expr);
	121	if (base == NULL_TREE
	122	\|\| TREE_CODE (base) == SSA_NAME
	123	\|\| TREE_CODE (base) == STRING_CST)
	124	return false;
	125
	126	tcode = TREE_CODE (expr);
	127
	128	/* Below are things we do not instrument
	129	(no possibility of races or not implemented yet). */
	130	if (/* Compiler-emitted artificial variables. */
	131	(DECL_P (expr) && DECL_ARTIFICIAL (expr))
	132	/* The var does not live in memory -> no possibility of races. */
	133	\|\| (tcode == VAR_DECL
	134	&& !TREE_ADDRESSABLE (expr)
	135	&& TREE_STATIC (expr) == 0)
	136	/* Not implemented. */
	137	\|\| TREE_CODE (TREE_TYPE (expr)) == RECORD_TYPE
	138	/* Not implemented. */
	139	\|\| tcode == CONSTRUCTOR
	140	/* Not implemented. */
	141	\|\| tcode == PARM_DECL
	142	/* Load of a const variable/parameter/field. */
	143	\|\| is_load_of_const_p (expr, is_write))
	144	return false;
	145
	146	size = int_size_in_bytes (TREE_TYPE (expr));
	147	if (size == -1)
	148	return false;
	149
	150	/* For now just avoid instrumenting bit field acceses.
	151	TODO: handle bit-fields as if touching the whole field. */
	152	HOST_WIDE_INT bitsize, bitpos;
	153	tree offset;
	154	enum machine_mode mode;
	155	int volatilep = 0, unsignedp = 0;
	156	get_inner_reference (expr, &bitsize, &bitpos, &offset,
	157	&mode, &unsignedp, &volatilep, false);
	158	if (bitpos % (size * BITS_PER_UNIT)
	159	\|\| bitsize != size * BITS_PER_UNIT)
	160	return false;
	161
8ddf5c28	162	/* TODO: handle other case: ARRAY_RANGE_REF. */
32b4b7f5 DV	163	if (tcode != ARRAY_REF
	164	&& tcode != VAR_DECL
	165	&& tcode != COMPONENT_REF
	166	&& tcode != INDIRECT_REF
	167	&& tcode != MEM_REF)
	168	return false;
	169
	170	stmt = gsi_stmt (gsi);
	171	loc = gimple_location (stmt);
	172	rhs = is_vptr_store (stmt, expr, is_write);
	173	gcc_checking_assert (rhs != NULL \|\| is_gimple_addressable (expr));
	174	expr_ptr = build_fold_addr_expr (unshare_expr (expr));
	175	if (rhs == NULL)
	176	{
	177	expr_type = TREE_TYPE (expr);
	178	while (TREE_CODE (expr_type) == ARRAY_TYPE)
	179	expr_type = TREE_TYPE (expr_type);
	180	size = int_size_in_bytes (expr_type);
	181	g = gimple_build_call (get_memory_access_decl (is_write, size),
	182	1, expr_ptr);
	183	}
	184	else
	185	{
	186	builtin_decl = builtin_decl_implicit (BUILT_IN_TSAN_VPTR_UPDATE);
	187	g = gimple_build_call (builtin_decl, 1, expr_ptr);
	188	}
	189	gimple_set_location (g, loc);
	190	/* Instrumentation for assignment of a function result
	191	must be inserted after the call. Instrumentation for
	192	reads of function arguments must be inserted before the call.
	193	That's because the call can contain synchronization. */
	194	if (is_gimple_call (stmt) && is_write)
	195	{
	196	/* If the call can throw, it must be the last stmt in
	197	a basic block, so the instrumented stmts need to be
8ddf5c28	198	inserted in successor bbs. */
32b4b7f5 DV	199	if (is_ctrl_altering_stmt (stmt))
	200	{
	201	edge e;
	202
	203	bb = gsi_bb (gsi);
	204	e = find_fallthru_edge (bb->succs);
	205	if (e)
	206	gsi_insert_seq_on_edge_immediate (e, g);
	207	}
	208	else
	209	gsi_insert_after (&gsi, g, GSI_NEW_STMT);
	210	}
	211	else
	212	gsi_insert_before (&gsi, g, GSI_SAME_STMT);
	213
	214	return true;
	215	}
	216
	217	/* Instruments the gimple pointed to by GSI. Return
8ddf5c28	218	true if func entry/exit should be instrumented. */
32b4b7f5 DV	219
	220	static bool
	221	instrument_gimple (gimple_stmt_iterator gsi)
	222	{
	223	gimple stmt;
	224	tree rhs, lhs;
	225	bool instrumented = false;
	226
	227	stmt = gsi_stmt (gsi);
	228	if (is_gimple_call (stmt)
	229	&& (gimple_call_fndecl (stmt)
	230	!= builtin_decl_implicit (BUILT_IN_TSAN_INIT)))
	231	return true;
8ddf5c28 JJ	232	else if (is_gimple_assign (stmt)
8ddf5c28 JJ	233	&& !gimple_clobber_p (stmt))
32b4b7f5 DV	234	{
	235	if (gimple_store_p (stmt))
	236	{
	237	lhs = gimple_assign_lhs (stmt);
	238	instrumented = instrument_expr (gsi, lhs, true);
	239	}
	240	if (gimple_assign_load_p (stmt))
	241	{
	242	rhs = gimple_assign_rhs1 (stmt);
	243	instrumented = instrument_expr (gsi, rhs, false);
	244	}
	245	}
	246	return instrumented;
	247	}
	248
	249	/* Instruments all interesting memory accesses in the current function.
8ddf5c28	250	Return true if func entry/exit should be instrumented. */
32b4b7f5 DV	251
	252	static bool
	253	instrument_memory_accesses (void)
	254	{
	255	basic_block bb;
	256	gimple_stmt_iterator gsi;
	257	bool fentry_exit_instrument = false;
	258
	259	FOR_EACH_BB (bb)
	260	for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	261	fentry_exit_instrument \|= instrument_gimple (gsi);
	262	return fentry_exit_instrument;
	263	}
	264
	265	/* Instruments function entry. */
	266
	267	static void
	268	instrument_func_entry (void)
	269	{
	270	basic_block succ_bb;
	271	gimple_stmt_iterator gsi;
	272	tree ret_addr, builtin_decl;
	273	gimple g;
	274
	275	succ_bb = single_succ (ENTRY_BLOCK_PTR);
	276	gsi = gsi_after_labels (succ_bb);
	277
	278	builtin_decl = builtin_decl_implicit (BUILT_IN_RETURN_ADDRESS);
	279	g = gimple_build_call (builtin_decl, 1, integer_zero_node);
	280	ret_addr = make_ssa_name (ptr_type_node, NULL);
	281	gimple_call_set_lhs (g, ret_addr);
	282	gimple_set_location (g, cfun->function_start_locus);
	283	gsi_insert_before (&gsi, g, GSI_SAME_STMT);
	284
	285	builtin_decl = builtin_decl_implicit (BUILT_IN_TSAN_FUNC_ENTRY);
	286	g = gimple_build_call (builtin_decl, 1, ret_addr);
	287	gimple_set_location (g, cfun->function_start_locus);
	288	gsi_insert_before (&gsi, g, GSI_SAME_STMT);
	289	}
	290
	291	/* Instruments function exits. */
	292
	293	static void
	294	instrument_func_exit (void)
	295	{
	296	location_t loc;
	297	basic_block exit_bb;
	298	gimple_stmt_iterator gsi;
	299	gimple stmt, g;
	300	tree builtin_decl;
	301	edge e;
	302	edge_iterator ei;
	303
	304	/* Find all function exits. */
	305	exit_bb = EXIT_BLOCK_PTR;
	306	FOR_EACH_EDGE (e, ei, exit_bb->preds)
	307	{
	308	gsi = gsi_last_bb (e->src);
	309	stmt = gsi_stmt (gsi);
	310	gcc_assert (gimple_code (stmt) == GIMPLE_RETURN);
	311	loc = gimple_location (stmt);
	312	builtin_decl = builtin_decl_implicit (BUILT_IN_TSAN_FUNC_EXIT);
	313	g = gimple_build_call (builtin_decl, 0);
	314	gimple_set_location (g, loc);
315	gsi_insert_before (&gsi, g, GSI_SAME_STMT);
316	}
317	}
318
319	/* ThreadSanitizer instrumentation pass. */
320
321	static unsigned
322	tsan_pass (void)
323	{
324	if (instrument_memory_accesses ())
325	{
326	instrument_func_entry ();
327	instrument_func_exit ();
328	}
329	return 0;
330	}
331
332	/* The pass's gate. */
333
334	static bool
335	tsan_gate (void)
336	{
337	return flag_tsan != 0
338	&& builtin_decl_implicit_p (BUILT_IN_TSAN_INIT);
339	}
340
341	/* Inserts __tsan_init () into the list of CTORs. */
342
343	void
344	tsan_finish_file (void)
345	{
346	tree ctor_statements;
347	tree init_decl;
348
349	ctor_statements = NULL_TREE;
350	init_decl = builtin_decl_implicit (BUILT_IN_TSAN_INIT);
351	append_to_statement_list (build_call_expr (init_decl, 0),
352	&ctor_statements);
353	cgraph_build_static_cdtor ('I', ctor_statements,
354	MAX_RESERVED_INIT_PRIORITY - 1);
355	}
356
357	/* The pass descriptor. */
358
359	struct gimple_opt_pass pass_tsan =
360	{
361	{
362	GIMPLE_PASS,
363	"tsan", /* name */
364	OPTGROUP_NONE, /* optinfo_flags */
365	tsan_gate, /* gate */
366	tsan_pass, /* execute */
367	NULL, /* sub */
368	NULL, /* next */
369	0, /* static_pass_number */
370	TV_NONE, /* tv_id */
371	PROP_ssa \| PROP_cfg, /* properties_required */
372	0, /* properties_provided */
373	0, /* properties_destroyed */
374	0, /* todo_flags_start */
8ddf5c28	375	TODO_verify_all \| TODO_update_ssa /* todo_flags_finish */
32b4b7f5 DV	376	}
	377	};
	378
	379	static bool
	380	tsan_gate_O0 (void)
	381	{
	382	return flag_tsan != 0 && !optimize
	383	&& builtin_decl_implicit_p (BUILT_IN_TSAN_INIT);
	384	}
	385
	386	struct gimple_opt_pass pass_tsan_O0 =
	387	{
	388	{
	389	GIMPLE_PASS,
	390	"tsan0", /* name */
	391	OPTGROUP_NONE, /* optinfo_flags */
	392	tsan_gate_O0, /* gate */
	393	tsan_pass, /* execute */
	394	NULL, /* sub */
	395	NULL, /* next */
	396	0, /* static_pass_number */
	397	TV_NONE, /* tv_id */
	398	PROP_ssa \| PROP_cfg, /* properties_required */
	399	0, /* properties_provided */
	400	0, /* properties_destroyed */
	401	0, /* todo_flags_start */
8ddf5c28	402	TODO_verify_all \| TODO_update_ssa /* todo_flags_finish */
32b4b7f5 DV	403	}
32b4b7f5 DV	404	};