RFR: 8199736: Define WIN32_LEAN_AND_MEAN before including windows.h

[Magnus Ihse Bursie]

On 2018-03-26 01:03, David Holmes wrote:
> Hi Robin,
>
> On 23/03/2018 10:37 PM, Robin Westberg wrote:
>> Hi Kim & Erik,
>>
>> Certainly makes sense to define it from the build system, I’ve 
>> updated the patch accordingly:
>>
>> Full: http://cr.openjdk.java.net/~rwestberg/8199736/webrev.01/ 
>> <http://cr.openjdk.java.net/~rwestberg/8199736/webrev.01/>
>> Incremental: 
>> http://cr.openjdk.java.net/~rwestberg/8199736/webrev.00-01/ 
>> <http://cr.openjdk.java.net/~rwestberg/8199736/webrev.00-01/>
>
> I'm a little unclear on the hotspot changes. If we define 
> WIN32_LEAN_AND_MEAN then certain APIs like sockets are excluded from 
> windows.h so we then have to include the specific header files like 
> winsock2.h - is that right?

Using WIN32_LEAN_AND_MEAN is good industry practice. We already do so 
for the JDK libraries. This trims down the number of files included by 
windows.h to a more manageble number. Several years ago, Microsoft did 
the (in my opinion) bad decision to let windows.h include a huge number 
of interfaces, unless this macro was defined. Using WIN32_LEAN_AND_MEAN 
and then explicitly including other API headers makes compilation 
faster, and the intention of the code clearer.

On top of this, due to naming conflicts, it is not possible at all to 
use winsock2.h unless you define WIN32_LEAN_AND_MEAN, windows.h will 
then pull in the old v1 of winsock.

/Magnus

>
> src/hotspot/share/interpreter/bytecodes.cpp
>
> I'm curious about this change. u_short comes from types.h on 
> non-Windows, is it simply missing on Windows (at least once we have 
> WIN32_LEAN_AND_MEAN defined) ?
>
> src/hotspot/share/utilities/ostream.cpp
>
> 1029 #endif
> 1030 #if defined(_WINDOWS)
>
> Using elif could be marginally faster given the two sets of conditions 
> are mutually exclusive.
>
> Thanks,
> David
>
>> (Not quite sure if the definition belongs where I put it or a bit 
>> later where most other windows-specific JVM flags are defined, but 
>> seemed reasonable to put it close to where it is defined for the JDK 
>> libraries).
>>
>> Best regards,
>> Robin
>>
>>> On 22 Mar 2018, at 16:52, Kim Barrett <kim.barrett at oracle.com> wrote:
>>>
>>>> On Mar 22, 2018, at 10:34 AM, Robin Westberg 
>>>> <robin.westberg at oracle.com> wrote:
>>>>
>>>> Hi all,
>>>>
>>>> Please review the following change that defines WIN32_LEAN_AND_MEAN 
>>>> [1] before including windows.h. This marginally improves build 
>>>> times, and makes it possible to include winsock2.h.
>>>>
>>>> Issue: https://bugs.openjdk.java.net/browse/JDK-8199736 
>>>> <https://bugs.openjdk.java.net/browse/JDK-8199736>
>>>> Webrev: http://cr.openjdk.java.net/~rwestberg/8199736/webrev.00/ 
>>>> <http://cr.openjdk.java.net/~rwestberg/8199736/webrev.00/>
>>>> Testing: hs-tier1
>>>>
>>>> Best regards,
>>>> Robin
>>>>
>>>> [1] 
>>>> https://msdn.microsoft.com/en-us/library/windows/desktop/aa383745%28v=vs.85%29.aspx#faster_builds_with_smaller_header_files 
>>>> <https://msdn.microsoft.com/en-us/library/windows/desktop/aa383745(v=vs.85).aspx#faster_builds_with_smaller_header_files> 
>>>>
>>>
>>> I think the addition of the WIN32_LEAN_AND_MEAN definition should be 
>>> done through the build
>>> system, so that it applies everywhere.
>>>
>>