[trans-mem] Test static constructors inside of transactional code

[trans-mem] Test static constructors inside of transactional code

[Torvald Riegel]

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Based on recent discussions among the C++ TM specification group, static
constructors should be allowed in transactional (i.e., transaction_safe)
code. GCC should have a wrapper assigment for __cxa_guard_acquire and
__cxa_guard_release, and libitm should implement wrappers that guarantee
atomicity of these constructors wrt the enclosing transaction.

If we find out that supporting and implementing isn't feasible in
practice, GCC should provide a better error message (eg, "static
constructors not allowed in transactional code" instead of complaining
about the __cxa* functions), and we should move this test to the GCC
tests.

OK for branch?

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commit 537788ae46aec7fcc45eee5ae56cfe3314a9ef11
Author: Torvald Riegel <triegel@redhat.com>
Date:   Wed Aug 3 13:31:46 2011 +0200

    Test static constructors inside of transactional code.
    
    	* testsuite/libitm.c++/static_ctor.C: New file.

diff --git a/libitm/testsuite/libitm.c++/static_ctor.C b/libitm/testsuite/libitm.c++/static_ctor.C
new file mode 100644
index 0000000..f618f68
--- /dev/null
+++ b/libitm/testsuite/libitm.c++/static_ctor.C
@@ -0,0 +1,38 @@
+// { dg-do run }
+/* Tests static constructors inside of transactional code.  */
+
+#include <pthread.h>
+#include <stdlib.h>
+
+int f(int x) __attribute__((noinline,transaction_safe));
+int f(int x)
+{
+  static int y = x;
+  return y*x;
+}
+
+static void *thread (void *dummy __attribute__((unused)))
+{
+  int bar;
+  __transaction { bar = f(10); }
+  if (bar != 100)
+    abort();
+  return 0;
+}
+
+int main()
+{
+  int bar;
+
+  // First, initialize y in another thread.
+  pthread_t pt;
+  pthread_create(&pt, NULL, thread, NULL);
+  pthread_join(pt, NULL);
+
+  // Now y should already be initialized.
+  __transaction { bar = f(20); }
+  if (bar != 200)
+    abort();
+
+  return 0;
+}

Re: [trans-mem] Test static constructors inside of transactional code

[Richard Henderson]

On 08/03/2011 04:57 AM, Torvald Riegel wrote:
>     Test static constructors inside of transactional code.
>     
>     	* testsuite/libitm.c++/static_ctor.C: New file.

Ok.


> +static void *thread (void *dummy __attribute__((unused)))

This is C++.  Unnamed parameters work.


r~