Cross referenced this patch from
https://code.google.com/p/thread-sanitizer/issues/detail?id=78
On Tue, Dec 16, 2014 at 12:25 PM, Dmitry Vyukov <dvyu...@google.com> wrote:
> I am not qualified to review the actual code changes, but from the
> description it looks good to me.
>
> It adds a EH frame to every function, right? In 64-bit mode there is
> no runtime penalty, right? Do you have any idea about binary size
> increase? Does gcc build in C++ mode nowadays? It can be a good test.
>
> I am somewhat worried about potential corner cases that can lead to
> compiler crashes or missed/excessive func_entry/exit calls. But I
> guess there is no way to make it working w/o getting some code in
> first. Rigorous testing would require running a large C++ app that
> actually throws and catches exception and precisely verifying stacks
> in reports.
>
>
> On Mon, Dec 15, 2014 at 9:50 PM, Jakub Jelinek <ja...@redhat.com> wrote:
>> Hi!
>>
>> As discussed in the PR, to support exceptions in -fsanitize=thread code,
>> it is desirable to call __tsan_func_exit also when leaving functions by
>> means of exceptions.
>>
>> Adding EH too late sounds too hard to me, so this patch instead adds an
>> internal call during gimplification, makes sure the inliner removes the
>> internal calls from the inline functions
>> (we don't care about inlines, only about functions we emit), and
>> for functions that didn't go through gimplify_function_tree (e.g. omp/tm
>> etc. functions) just keeps using the old __tsan_func_exit additions.
>>
>> Bootstrapped/regtested on x86_64-linux and i686-linux. Ok for trunk?
>>
>> On:
>> #include <pthread.h>
>>
>> int v;
>>
>> int
>> foo (int x)
>> {
>> if (x < 99)
>> throw x;
>> v++;
>> return x;
>> }
>>
>> void *
>> tf (void *)
>> {
>> for (int i = 0; i < 100; i++)
>> try { foo (i); } catch (int) {}
>> return NULL;
>> }
>>
>> int
>> main ()
>> {
>> pthread_t th;
>> if (pthread_create (&th, NULL, tf, NULL))
>> return 0;
>> v++;
>> pthread_join (th, NULL);
>> return 0;
>> }
>>
>> I used to get without this patch:
>> ==================
>> WARNING: ThreadSanitizer: data race (pid=20449)
>> Read of size 4 at 0x0000006020e0 by thread T1:
>> #0 foo(int) /usr/src/gcc/obj/gcc/ts.C:10 (ts+0x000000400cb9)
>> #1 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #2 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #3 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #4 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #5 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #6 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #7 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #8 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #9 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #10 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #11 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #12 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #13 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #14 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #15 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #16 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #17 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #18 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #19 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #20 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #21 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #22 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #23 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #24 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #25 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #26 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #27 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #28 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #29 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #30 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #31 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #32 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #33 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #34 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #35 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #36 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #37 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #38 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #39 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #40 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #41 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #42 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #43 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #44 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #45 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #46 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #47 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #48 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #49 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #50 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #51 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #52 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #53 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #54 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #55 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #56 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #57 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #58 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #59 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #60 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #61 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #62 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #63 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #64 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #65 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #66 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #67 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #68 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #69 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #70 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #71 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #72 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #73 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #74 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #75 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #76 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #77 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #78 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #79 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #80 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #81 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #82 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #83 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #84 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #85 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #86 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #87 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #88 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #89 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #90 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #91 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #92 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #93 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #94 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #95 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #96 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #97 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #98 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #99 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>> #100 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d13)
>>
>> Previous write of size 4 at 0x0000006020e0 by main thread:
>> #0 main /usr/src/gcc/obj/gcc/ts.C:28 (ts+0x000000400db9)
>>
>> Location is global '<null>' of size 0 at 0x000000000000
>> (ts+0x0000006020e0)
>>
>> Thread T1 (tid=20451, running) created by main thread at:
>> #0 pthread_create ../../../../libsanitizer/tsan/tsan_interceptors.cc:895
>> #(libtsan.so.0+0x0000000278d4)
>> #1 main /usr/src/gcc/obj/gcc/ts.C:26 (ts+0x000000400d8c)
>>
>> SUMMARY: ThreadSanitizer: data race /usr/src/gcc/obj/gcc/ts.C:10 foo(int)
>> ==================
>> ThreadSanitizer: reported 1 warnings
>>
>> and with this patch I get:
>> ==================
>> WARNING: ThreadSanitizer: data race (pid=20788)
>> Read of size 4 at 0x0000006020e0 by thread T1:
>> #0 foo(int) /usr/src/gcc/obj/gcc/ts.C:10 (ts+0x000000400cb9)
>> #1 tf(void*) /usr/src/gcc/obj/gcc/ts.C:18 (ts+0x000000400d28)
>>
>> Previous write of size 4 at 0x0000006020e0 by main thread:
>> #0 main /usr/src/gcc/obj/gcc/ts.C:28 (ts+0x000000400dd9)
>>
>> Location is global '<null>' of size 0 at 0x000000000000
>> (ts+0x0000006020e0)
>>
>> Thread T1 (tid=20790, running) created by main thread at:
>> #0 pthread_create ../../../../libsanitizer/tsan/tsan_interceptors.cc:895
>> #(libtsan.so.0+0x0000000278d4)
>> #1 main /usr/src/gcc/obj/gcc/ts.C:26 (ts+0x000000400dac)
>>
>> SUMMARY: ThreadSanitizer: data race /usr/src/gcc/obj/gcc/ts.C:10 foo(int)
>> ==================
>> ThreadSanitizer: reported 1 warnings
>>
>> 2014-12-15 Jakub Jelinek <ja...@redhat.com>
>>
>> PR sanitizer/64265
>> * gimplify.c (gimplify_function_tree): Add TSAN_FUNC_EXIT internal
>> call as cleanup of the whole body.
>> * internal-fn.def (TSAN_FUNC_EXIT): New internal call.
>> * tsan.c (replace_func_exit): New function.
>> (instrument_func_exit): Moved earlier.
>> (instrument_memory_accesses): Adjust TSAN_FUNC_EXIT internal calls.
>> Call instrument_func_exit if no TSAN_FUNC_EXIT internal calls have
>> been found.
>> (tsan_pass): Don't call instrument_func_exit.
>> * internal-fn.c (expand_TSAN_FUNC_EXIT): New function.
>> * tree-inline.c (copy_bb): Drop TSAN_FUNC_EXIT internal calls during
>> inlining.
>>
>> --- gcc/internal-fn.def.jj 2014-12-13 12:09:38.545301645 +0100
>> +++ gcc/internal-fn.def 2014-12-15 13:26:41.315704348 +0100
>> @@ -60,3 +60,4 @@ DEF_INTERNAL_FN (ASAN_CHECK, ECF_TM_PURE
>> DEF_INTERNAL_FN (ADD_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
>> DEF_INTERNAL_FN (SUB_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
>> DEF_INTERNAL_FN (MUL_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
>> +DEF_INTERNAL_FN (TSAN_FUNC_EXIT, ECF_NOVOPS | ECF_LEAF | ECF_NOTHROW, NULL)
>> --- gcc/tree-inline.c.jj 2014-11-29 12:35:01.000000000 +0100
>> +++ gcc/tree-inline.c 2014-12-15 13:40:49.477018309 +0100
>> @@ -1902,7 +1902,7 @@ copy_bb (copy_body_data *id, basic_block
>> gsi_replace (©_gsi, new_call, false);
>> stmt = new_call;
>> }
>> - else if (is_gimple_call (stmt)
>> + else if (call_stmt
>> && id->call_stmt
>> && (decl = gimple_call_fndecl (stmt))
>> && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
>> @@ -1929,6 +1929,15 @@ copy_bb (copy_body_data *id, basic_block
>> gsi_replace (©_gsi, new_stmt, false);
>> stmt = new_stmt;
>> }
>> + else if (call_stmt
>> + && id->call_stmt
>> + && gimple_call_internal_p (stmt)
>> + && gimple_call_internal_fn (stmt) == IFN_TSAN_FUNC_EXIT)
>> + {
>> + /* Drop TSAN_FUNC_EXIT () internal calls during inlining. */
>> + gsi_remove (©_gsi, false);
>> + continue;
>> + }
>>
>> /* Statements produced by inlining can be unfolded, especially
>> when we constant propagated some operands. We can't fold
>> --- gcc/gimplify.c.jj 2014-12-13 12:09:38.923295132 +0100
>> +++ gcc/gimplify.c 2014-12-15 13:26:41.315704348 +0100
>> @@ -9049,6 +9049,22 @@ gimplify_function_tree (tree fndecl)
>> seq = NULL;
>> gimple_seq_add_stmt (&seq, new_bind);
>> gimple_set_body (fndecl, seq);
>> + bind = new_bind;
>> + }
>> +
>> + if (flag_sanitize & SANITIZE_THREAD)
>> + {
>> + gcall *call = gimple_build_call_internal (IFN_TSAN_FUNC_EXIT, 0);
>> + gimple tf = gimple_build_try (seq, call, GIMPLE_TRY_FINALLY);
>> + gbind *new_bind = gimple_build_bind (NULL, tf, gimple_bind_block
>> (bind));
>> + /* Clear the block for BIND, since it is no longer directly inside
>> + the function, but within a try block. */
>> + gimple_bind_set_block (bind, NULL);
>> + /* Replace the current function body with the body
>> + wrapped in the try/finally TF. */
>> + seq = NULL;
>> + gimple_seq_add_stmt (&seq, new_bind);
>> + gimple_set_body (fndecl, seq);
>> }
>>
>> DECL_SAVED_TREE (fndecl) = NULL_TREE;
>> --- gcc/tsan.c.jj 2014-12-15 10:37:21.853609776 +0100
>> +++ gcc/tsan.c 2014-12-15 13:29:51.768406631 +0100
>> @@ -631,6 +631,47 @@ instrument_gimple (gimple_stmt_iterator
>> return instrumented;
>> }
>>
>> +/* Replace TSAN_FUNC_EXIT internal call with function exit tsan builtin. */
>> +
>> +static void
>> +replace_func_exit (gimple stmt)
>> +{
>> + tree builtin_decl = builtin_decl_implicit (BUILT_IN_TSAN_FUNC_EXIT);
>> + gimple g = gimple_build_call (builtin_decl, 0);
>> + gimple_set_location (g, cfun->function_end_locus);
>> + gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
>> + gsi_replace (&gsi, g, true);
>> +}
>> +
>> +/* Instrument function exit. Used when TSAN_FUNC_EXIT does not exist. */
>> +
>> +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_FN (cfun);
>> + 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
>> + || gimple_call_builtin_p (stmt, BUILT_IN_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);
>> + }
>> +}
>> +
>> /* Instruments all interesting memory accesses in the current function.
>> Return true if func entry/exit should be instrumented. */
>>
>> @@ -640,10 +681,38 @@ instrument_memory_accesses (void)
>> basic_block bb;
>> gimple_stmt_iterator gsi;
>> bool fentry_exit_instrument = false;
>> + bool func_exit_seen = false;
>> + auto_vec<gimple> tsan_func_exits;
>>
>> FOR_EACH_BB_FN (bb, cfun)
>> for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
>> - fentry_exit_instrument |= instrument_gimple (&gsi);
>> + {
>> + gimple stmt = gsi_stmt (gsi);
>> + if (is_gimple_call (stmt)
>> + && gimple_call_internal_p (stmt)
>> + && gimple_call_internal_fn (stmt) == IFN_TSAN_FUNC_EXIT)
>> + {
>> + if (fentry_exit_instrument)
>> + replace_func_exit (stmt);
>> + else
>> + tsan_func_exits.safe_push (stmt);
>> + func_exit_seen = true;
>> + }
>> + else
>> + fentry_exit_instrument |= instrument_gimple (&gsi);
>> + }
>> + unsigned int i;
>> + gimple stmt;
>> + FOR_EACH_VEC_ELT (tsan_func_exits, i, stmt)
>> + if (fentry_exit_instrument)
>> + replace_func_exit (stmt);
>> + else
>> + {
>> + gsi = gsi_for_stmt (stmt);
>> + gsi_remove (&gsi, true);
>> + }
>> + if (fentry_exit_instrument && !func_exit_seen)
>> + instrument_func_exit ();
>> return fentry_exit_instrument;
>> }
>>
>> @@ -672,35 +741,6 @@ instrument_func_entry (void)
>> gsi_insert_seq_on_edge_immediate (e, seq);
>> }
>>
>> -/* 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_FN (cfun);
>> - 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
>> - || gimple_call_builtin_p (stmt, BUILT_IN_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
>> @@ -708,10 +748,7 @@ tsan_pass (void)
>> {
>> initialize_sanitizer_builtins ();
>> if (instrument_memory_accesses ())
>> - {
>> - instrument_func_entry ();
>> - instrument_func_exit ();
>> - }
>> + instrument_func_entry ();
>> return 0;
>> }
>>
>> --- gcc/internal-fn.c.jj 2014-12-13 12:09:38.822296872 +0100
>> +++ gcc/internal-fn.c 2014-12-15 13:26:41.317704313 +0100
>> @@ -208,6 +208,14 @@ expand_ASAN_CHECK (gcall *stmt ATTRIBUTE
>> gcc_unreachable ();
>> }
>>
>> +/* This should get expanded in the tsan pass. */
>> +
>> +static void
>> +expand_TSAN_FUNC_EXIT (gcall *)
>> +{
>> + gcc_unreachable ();
>> +}
>> +
>> /* Helper function for expand_addsub_overflow. Return 1
>> if ARG interpreted as signed in its precision is known to be always
>> positive or 2 if ARG is known to be always negative, or 3 if ARG may
>>
>> Jakub
