From 06712fc68dc9843d9af7c7ac10047f49d305ad76 Mon Sep 17 00:00:00 2001 From: Marco Elver Date: Wed, 10 Jun 2020 16:21:21 +0200 Subject: [PATCH] tsan: Add param to disable func-entry-exit instrumentation 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-elver@google.com/ gcc/ChangeLog: * gimplify.c (gimplify_function_tree): Optimize and do not emit IFN_TSAN_FUNC_EXIT in a finally block if we do not need it. * params.opt: Add --param=tsan-instrument-func-entry-exit=. * tsan.c (instrument_memory_accesses): Make fentry_exit_instrument bool depend on new 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. --- 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; -- 2.30.2