On 24/03/21 03:53 -0300, Alexandre Oliva wrote:
On target systems that don't support any random_device, not even the
default one,
It should be impossible to have no random_device. As a fallback a
pseudo random number generator should be used.
other random_device constructor tests are disabled by
dg-require-effective-target random_device. The token.cc also
exercises the default constructor, in a way that doesn't expect an
exception to be raised, but it's not guarded by the same requirement.
Other potentially-raising ctors in token.cc expect exceptions and
handle them, but the ("default")-constructed one does not, so the
program terminates and the test fails without exercising the other
constructor variants.
Why does the "default" token cause an exception?
This patch arranges to disable the test altogether when the
random_device feature is not available. A reasonable alternative
would be to install a std::runtime_error handler around the test01
body, so that we exercise at least the exception raising, but then
test03 would have to be relaxed, since without even "default", it
likely wouldn't meet the tested requirement there.
Regstrapped on x86_64-linux-gnu and cross-tested for x86_64-vx7r2 along
with other patches, mostly for the testsuite. Ok to install?
No, that would disable the test for Windows, where it works OK.
The 'random_device' effective-target is poorly named, it checks
whether the _GLIBCXX_USE_RANDOM_TR1 macro is defined, which is even
more poorly named. That macro is defined when /dev/random and
/dev/urandom are available. But we support std::random_device without
those files (e.g. on Windows).
If the default constructor throws then that suggests your target is
misconfigured. Why isn't the mt19937 PRNG being used?
for libstdc++-v3/ChangeLog
* testsuite/26_numerics/random/random_device/cons/token.cc:
Require effective target feature random_device.
---
.../26_numerics/random/random_device/cons/token.cc | 1 +
1 file changed, 1 insertion(+)
diff --git
a/libstdc++-v3/testsuite/26_numerics/random/random_device/cons/token.cc
b/libstdc++-v3/testsuite/26_numerics/random/random_device/cons/token.cc
index defb8d58c586a..105ae0ba87743 100644
--- a/libstdc++-v3/testsuite/26_numerics/random/random_device/cons/token.cc
+++ b/libstdc++-v3/testsuite/26_numerics/random/random_device/cons/token.cc
@@ -1,4 +1,5 @@
// { dg-do run { target c++11 } }
+// { dg-require-effective-target random_device }
// { dg-require-cstdint "" }
//
// 2008-11-24 Edward M. Smith-Rowland <3dw...@verizon.net>
--
Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/
Free Software Activist GNU Toolchain Engineer
Vim, Vi, Voltei pro Emacs -- GNUlius Caesar
