On 12/9/20 2:24 AM, Martin Liška wrote:
Hello.
The newly added warning is about warning a user
that std::atomic_thread_fence is not supported by TSAN.
Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
Ready to be installed?
Thanks,
Martin
gcc/ChangeLog:
PR sanitizer/97868
* common.opt: Add new warning -Wtsan.
* doc/invoke.texi: Likewise.
* tsan.c (instrument_builtin_call): Warn users about unsupported
std::atomic_thread_fence.
---
gcc/common.opt | 4 ++++
gcc/doc/invoke.texi | 8 +++++++-
gcc/tsan.c | 6 ++++++
3 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/gcc/common.opt b/gcc/common.opt
index 6645539f5e5..6c24c7bbffb 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -842,6 +842,10 @@ Wvector-operation-performance
Common Var(warn_vector_operation_performance) Warning
Warn when a vector operation is compiled outside the SIMD.
+Wtsan
+Common Var(warn_tsan) Init(1) Warning
+Warn about unsupported features in the ThreadSanitizer.
^^^
Just a minor grammatical nit. As a name, ThreadSanitizer should
not be preceded by an article. Same in invoke.texi below.
+
Xassembler
Driver Separate
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index f7e8c8b29b0..5bd18c78e99 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -377,7 +377,7 @@ Objective-C and Objective-C++ Dialects}.
-Wswitch -Wno-switch-bool -Wswitch-default -Wswitch-enum @gol
-Wno-switch-outside-range -Wno-switch-unreachable -Wsync-nand @gol
-Wsystem-headers -Wtautological-compare -Wtrampolines -Wtrigraphs @gol
--Wtype-limits -Wundef @gol
+-Wtsan -Wtype-limits -Wundef @gol
-Wuninitialized -Wunknown-pragmas @gol
-Wunsuffixed-float-constants -Wunused @gol
-Wunused-but-set-parameter -Wunused-but-set-variable @gol
@@ -7951,6 +7951,12 @@ Note that the code above is invalid in C++11.
This warning is enabled by default.
+@item -Wtsan
+@opindex Wtsan
+@opindex Wno-tsan
+Warn about unsupported features in the ThreadSanitizer.
+This warning is enabled by default.
+
@item -Wtype-limits
@opindex Wtype-limits
@opindex Wno-type-limits
diff --git a/gcc/tsan.c b/gcc/tsan.c
index 4d6223454b5..be9fabea62a 100644
--- a/gcc/tsan.c
+++ b/gcc/tsan.c
@@ -45,6 +45,7 @@ along with GCC; see the file COPYING3. If not see
#include "asan.h"
#include "builtins.h"
#include "target.h"
+#include "diagnostic-core.h"
/* Number of instrumented memory accesses in the current function. */
@@ -500,6 +501,11 @@ instrument_builtin_call (gimple_stmt_iterator *gsi)
continue;
else
{
+ if (fcode == BUILT_IN_ATOMIC_THREAD_FENCE)
+ warning_at (gimple_location (stmt), OPT_Wtsan,
+ "%qs is not supported by ThreadSanitizer and may "
+ "lead to false positives", "atomic_thread_fence");
Most similar warnings mention the sanitizer option rather than
referring to the tool by name. E.g.,
"transactional memory is not supported with %<-fsanitize=address%>"
or
"%<-fsanitize=leak%> is incompatible with %<-fsanitize=thread%>"
For the sake of consistency (and also to provide a bit of additional
detail) I would suggest to follow that style.
Martin
+
tree decl = builtin_decl_implicit (tsan_atomic_table[i].tsan_fcode);
if (decl == NULL_TREE)
return;
