Adds param tsan-instrument-func-entry-exit, which controls if
__tsan_func_{entry,exit} calls should be emitted or not. The default
behaviour is to emit the calls.
This may be required by alternative race detection runtimes. One such
runtime is the Kernel Concurrency Sanitizer (KCSAN):
https://github.com/google/ktsan/wiki/KCSAN
After this change, GCC should satisfy all requirements for KCSAN:
https://lore.kernel.org/lkml/20200515150338.190344-7-el...@google.com/
gcc/ChangeLog:
* params.opt: Add --param=tsan-instrument-func-entry-exit=.
* tsan.c (instrument_gimple): Make return value if func entry
and exit should be instrumented dependent on param.
gcc/testsuite/ChangeLog:
* c-c++-common/tsan/func_entry_exit.c: New test.
* c-c++-common/tsan/func_entry_exit_disabled.c: New test.
---
v2:
* Instead of modifying the return value of instrument_gimple(), change
the boolean expression for fentry_exit_instrument.
* Optimize gimplify and do not emit IFN_TSAN_FUNC_EXIT in a finally
block if we do not need it.
* Change test to also look at gimple dump.
---
gcc/gimplify.c | 3 +-
gcc/params.opt | 4 +++
.../c-c++-common/tsan/func_entry_exit.c | 29 +++++++++++++++++++
.../tsan/func_entry_exit_disabled.c | 29 +++++++++++++++++++
gcc/tsan.c | 4 ++-
5 files changed, 67 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/c-c++-common/tsan/func_entry_exit.c
create mode 100644 gcc/testsuite/c-c++-common/tsan/func_entry_exit_disabled.c
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index e14932fafaf..416fb609b94 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -15011,7 +15011,8 @@ gimplify_function_tree (tree fndecl)
bind = new_bind;
}
- if (sanitize_flags_p (SANITIZE_THREAD))
+ if (sanitize_flags_p (SANITIZE_THREAD)
+ && param_tsan_instrument_func_entry_exit)
{
gcall *call = gimple_build_call_internal (IFN_TSAN_FUNC_EXIT, 0);
gimple *tf = gimple_build_try (seq, call, GIMPLE_TRY_FINALLY);
diff --git a/gcc/params.opt b/gcc/params.opt
index 9b564bb046c..e29a44e7712 100644
--- a/gcc/params.opt
+++ b/gcc/params.opt
@@ -912,6 +912,10 @@ Set the maximum number of instructions executed in
parallel in reassociated tree
Common Joined UInteger Var(param_tsan_distinguish_volatile) IntegerRange(0, 1)
Param
Emit special instrumentation for accesses to volatiles.
+-param=tsan-instrument-func-entry-exit=
+Common Joined UInteger Var(param_tsan_instrument_func_entry_exit) Init(1)
IntegerRange(0, 1) Param
+Emit instrumentation calls to __tsan_func_entry() and __tsan_func_exit().
+
-param=uninit-control-dep-attempts=
Common Joined UInteger Var(param_uninit_control_dep_attempts) Init(1000)
IntegerRange(1, 65536) Param Optimization
Maximum number of nested calls to search for control dependencies during
uninitialized variable analysis.
diff --git a/gcc/testsuite/c-c++-common/tsan/func_entry_exit.c
b/gcc/testsuite/c-c++-common/tsan/func_entry_exit.c
new file mode 100644
index 00000000000..9c1b697411c
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/tsan/func_entry_exit.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-gimple -fdump-tree-optimized" } */
+
+int x;
+
+__attribute__((noinline))
+void fn1(void)
+{
+ x++;
+}
+
+__attribute__((noinline))
+void fn2(void)
+{
+ fn1();
+}
+
+__attribute__((noinline))
+int main(int argc, char *argv[])
+{
+ fn1();
+ fn2();
+ return 0;
+}
+
+// { dg-final { scan-tree-dump "TSAN_FUNC_EXIT" "gimple" } }
+// { dg-final { scan-tree-dump-times "__tsan_func_entry" 3 "optimized" } }
+// { dg-final { scan-tree-dump-times "__tsan_func_exit" 3 "optimized" } }
+// { dg-final { scan-tree-dump "__tsan_write" "optimized" } }
diff --git a/gcc/testsuite/c-c++-common/tsan/func_entry_exit_disabled.c
b/gcc/testsuite/c-c++-common/tsan/func_entry_exit_disabled.c
new file mode 100644
index 00000000000..63cc73b9eba
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/tsan/func_entry_exit_disabled.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "--param=tsan-instrument-func-entry-exit=0 -fdump-tree-gimple
-fdump-tree-optimized" } */
+
+int x;
+
+__attribute__((noinline))
+void fn1(void)
+{
+ x++;
+}
+
+__attribute__((noinline))
+void fn2(void)
+{
+ fn1();
+}
+
+__attribute__((noinline))
+int main(int argc, char *argv[])
+{
+ fn1();
+ fn2();
+ return 0;
+}
+
+// { dg-final { scan-tree-dump-not "TSAN_FUNC_EXIT" "gimple" } }
+// { dg-final { scan-tree-dump-not "__tsan_func_entry" "optimized" } }
+// { dg-final { scan-tree-dump-not "__tsan_func_exit" "optimized" } }
+// { dg-final { scan-tree-dump "__tsan_write" "optimized" } }
diff --git a/gcc/tsan.c b/gcc/tsan.c
index 447acccfafd..4d6223454b5 100644
--- a/gcc/tsan.c
+++ b/gcc/tsan.c
@@ -804,7 +804,9 @@ instrument_memory_accesses (bool *cfg_changed)
func_exit_seen = true;
}
else
- fentry_exit_instrument |= instrument_gimple (&gsi);
+ fentry_exit_instrument
+ |= (instrument_gimple (&gsi)
+ && param_tsan_instrument_func_entry_exit);
}
if (gimple_purge_dead_eh_edges (bb))
*cfg_changed = true;
--
2.27.0.290.gba653c62da-goog
