RFR: 8247910: Improve alignment and power-of-2 utilities using C++14

[Thomas Stüfe]

Hi,

unfortunately this breaks my builds on Ubuntu 16.4. I am using gcc 5.4.0
which according to https://openjdk.java.net/groups/build/doc/building.html
should still be an accepted compiler?

Creating hotspot/variant-server/libjvm/gtest/gtestLauncher from 1 file(s)
In file included from
/shared/projects/openjdk/jdk-jep387/source/src/hotspot/share/services/memTracker.hpp:85:0,
                 from
/shared/projects/openjdk/jdk-jep387/source/src/hotspot/share/precompiled/precompiled.hpp:60:
/shared/projects/openjdk/jdk-jep387/source/src/hotspot/share/services/mallocTracker.hpp:190:78:
error: size of array '_snapshot' is not an integral constant-expression
   static size_t _snapshot[CALC_OBJ_SIZE_IN_TYPE(MallocMemorySnapshot,
size_t)];

  ^
In file included from
/shared/projects/openjdk/jdk-jep387/source/src/hotspot/share/services/memTracker.hpp:87:0,
                 from
/shared/projects/openjdk/jdk-jep387/source/src/hotspot/share/precompiled/precompiled.hpp:60:
/shared/projects/openjdk/jdk-jep387/source/src/hotspot/share/services/virtualMemoryTracker.hpp:170:79:
error: size of array '_snapshot' is not an integral constant-expression
   static size_t _snapshot[CALC_OBJ_SIZE_IN_TYPE(VirtualMemorySnapshot,
size_t)];

   ^
In file included from
/shared/projects/openjdk/jdk-jep387/source/src/hotspot/share/services/memTracker.hpp:85:0,
                 from
/shared/projects/openjdk/jdk-jep387/source/src/hotspot/share/precompiled/precompiled.hpp:60:
/shared/projects/openjdk/jdk-jep387/source/src/hotspot/share/services/mallocTracker.hpp:190:78:
error: size of array '_snapshot' is not an integral constant-expression
   static size_t _snapshot[CALC_OBJ_SIZE_IN_TYPE(MallocMemorySnapshot,
size_t)];

  ^
In file included from
/shared/projects/openjdk/jdk-jep387/source/src/hotspot/share/services/memTracker.hpp:87:0,
                 from
/shared/projects/openjdk/jdk-jep387/source/src/hotspot/share/precompiled/precompiled.hpp:60:
/shared/projects/openjdk/jdk-jep387/source/src/hotspot/share/services/virtualMemoryTracker.hpp:170:79:
error: size of array '_snapshot' is not an integral constant-expression
   static size_t _snapshot[CALC_OBJ_SIZE_IN_TYPE(VirtualMemorySnapshot,
size_t)];

   ^
cc1plus: error: unrecognized command line option
'-Wno-shift-negative-value' [-Werror]
cc1plus: error: unrecognized command line option '-Wno-cast-function-type'
[-Werror]

Cheers, Thomas


On Tue, Sep 15, 2020 at 12:09 AM Kim Barrett <kim.barrett at oracle.com> wrote:

> > On Sep 14, 2020, at 3:43 AM, Stefan Karlsson <stefank at openjdk.java.net>
> wrote:
> >
> > On Fri, 11 Sep 2020 08:44:49 GMT, Kim Barrett <kbarrett at openjdk.org>
> wrote:
> >
> >> Please review this change which updates the alignment and power-of-2
> >> utilities (utilities/align.hpp and utilities/powerOfTwo.hpp) to use
> >> C++14 features.
> >>
> >> Where possible, the alignment functions are now constexpr.  This
> >> eliminates the need for alternate macros that needed to be used in
> >> constexpr contexts.
> >>
> >> Use <type_traits> and <limits> rather than HotSpot workalikes.
> >> We no longer need max_value<T>(), as the problematic platform for
> >> std::numeric_limits<T>::max() was Solaris.
> >>
> >> Testing: tier1
> >
> > Looks good!
> >
> > -------------
> >
> > Marked as reviewed by stefank (Reviewer).
> >
> > PR: https://git.openjdk.java.net/jdk/pull/126
>
> Thanks.
>
>