Hi!
I found that with GCC's '-fthreadsafe-statics' implementation (..., which
is enabled by default) instrumented as follows:
--- libstdc++-v3/libsupc++/guard.cc
+++ libstdc++-v3/libsupc++/guard.cc
@@ -271,6 +273,7 @@ namespace __cxxabiv1
extern "C"
int __cxa_guard_acquire (__guard *g)
{
+ asm("int3");
#ifdef __GTHREADS
// If the target can reorder loads, we need to insert a read memory
// barrier so that accesses to the guarded variable happen after the
..., there is only one single libgomp C++ test case where this triggers;
'libgomp.c++/taskloop-6.C':
Thread 1 "a.out" received signal SIGTRAP, Trace/breakpoint trap.
__cxxabiv1::__cxa_guard_acquire (g=0x60b228 <guard variable for
f17<121>(J<int>)::i>) at [...]/source-gcc/libstdc++-v3/libsupc++/guard.cc:281
281 if (_GLIBCXX_GUARD_TEST_AND_ACQUIRE (g))
(gdb) bt
#0 __cxxabiv1::__cxa_guard_acquire (g=0x60b228 <guard variable for
f17<121>(J<int>)::i>) at [...]/source-gcc/libstdc++-v3/libsupc++/guard.cc:281
#1 0x0000000000404772 in f17<121> (j=...) at
source-gcc/libgomp/testsuite/libgomp.c++/taskloop-6.C:300
#2 0x0000000000401e11 in main () at
source-gcc/libgomp/testsuite/libgomp.c++/taskloop-6.C:411
That test case however isn't per se testing behavior of a C++ static
local variable vs. OpenMP.
OK to push the attached "Add 'libgomp.c++/static-local-variable-1.C'"?
(Also, I'm happy to extend the test case to verify any additional
features you think are userful to be tested there.)
(With '-fno-threadsafe-statics', this fails, as expected.)
Grüße
Thomas
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>From d3140a1b4a649c5acb3735ef7fd04a4ebffe5e9a Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <tho...@codesourcery.com>
Date: Fri, 17 Nov 2023 16:06:25 +0100
Subject: [PATCH] Add 'libgomp.c++/static-local-variable-1.C'
A debug run may look as follows:
int main()
void f()
S::S()
void f()
S::S()/
void f()
void f()/
void f()
void f()/
void f()
void f()/
void f()
void f()/
void f()
void f()/
void f()
void f()/
void f()
void f()/
void f()
void f()/
void f()
void f()/
void f()
void f()/
void f()/
void f()/
cSC = 1
cf = 12
int main()/
S::~S()
S::~S()/
libgomp/
* testsuite/libgomp.c++/static-local-variable-1.C: New.
---
.../libgomp.c++/static-local-variable-1.C | 95 +++++++++++++++++++
1 file changed, 95 insertions(+)
create mode 100644 libgomp/testsuite/libgomp.c++/static-local-variable-1.C
diff --git a/libgomp/testsuite/libgomp.c++/static-local-variable-1.C b/libgomp/testsuite/libgomp.c++/static-local-variable-1.C
new file mode 100644
index 00000000000..3169ba77d8d
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c++/static-local-variable-1.C
@@ -0,0 +1,95 @@
+// Test basic behavior of a C++ static local variable vs. OpenMP.
+
+#include <omp.h>
+#include <unistd.h>
+
+#define DEBUG_PRINTF //__builtin_printf
+
+static int state;
+
+static int cSC, cSD, cf;
+
+struct S
+{
+ S()
+ {
+ DEBUG_PRINTF("%s\n", __PRETTY_FUNCTION__);
+
+ int c;
+#pragma omp atomic capture
+ c = ++cSC;
+ if (c != 1)
+ __builtin_abort();
+
+ if (state++ != 1)
+ __builtin_abort();
+
+ DEBUG_PRINTF("%s/\n", __PRETTY_FUNCTION__);
+ }
+
+ ~S()
+ {
+ DEBUG_PRINTF("%s\n", __PRETTY_FUNCTION__);
+
+ int c;
+#pragma omp atomic capture
+ c = ++cSD;
+ if (c != 1)
+ __builtin_abort();
+
+ if (state++ != 3)
+ __builtin_abort();
+
+ DEBUG_PRINTF("%s/\n", __PRETTY_FUNCTION__);
+ // Exit '0', now that we've verified all is OK.
+ _exit(0);
+ }
+};
+
+static void f()
+{
+ DEBUG_PRINTF("%s\n", __PRETTY_FUNCTION__);
+
+#pragma omp atomic
+ ++cf;
+
+ // <https://en.cppreference.com/w/cpp/language/storage_duration#Static_local_variables>
+ static S s;
+
+ DEBUG_PRINTF("%s/\n", __PRETTY_FUNCTION__);
+}
+
+int main()
+{
+ DEBUG_PRINTF("%s\n", __PRETTY_FUNCTION__);
+
+ if (state++ != 0)
+ __builtin_abort();
+
+ int nthreads;
+
+#pragma omp parallel
+ {
+#pragma omp master
+ {
+ nthreads = omp_get_num_threads ();
+ }
+
+ f();
+ }
+
+ DEBUG_PRINTF(" cSC = %d\n", cSC);
+ DEBUG_PRINTF(" cf = %d\n", cf);
+ if (cSC != 1)
+ __builtin_abort();
+ if (cf != nthreads)
+ __builtin_abort();
+
+ if (state++ != 2)
+ __builtin_abort();
+
+ DEBUG_PRINTF("%s/\n", __PRETTY_FUNCTION__);
+
+ // See '_exit(0);' elsewhere.
+ return 1;
+}
--
2.34.1
