VS install found through --with-tools-dir value is discarded

[Jorn Vernee]

I ran the `clean images` targets with the different toolchains but 
didn't really notice any significant difference.

FWIW, for older versions of VS the x64 toolchain does seem to be preferred:

         VCVARSFILES="vc/bin/amd64/vcvars64.bat 
vc/bin/x86_amd64/vcvarsx86_amd64.bat \
             VC/Auxiliary/Build/vcvarsx86_amd64.bat 
VC/Auxiliary/Build/vcvars64.bat"

(The last 2 paths are for the newer version)

Using the x64 toolchain might be useful for preventing crashes due to 
running out of memory. I've run into a compiler/linker crash a couple of 
times in  the past, though I'm not sure they were caused by OOM, that 
seems the most likely to me.

Jorn

On 10/10/2019 19:52, Erik Joelsson wrote:
> Hello Jorn,
>
> On 2019-10-09 07:00, Jorn Vernee wrote:
>> Hi,
>>
>> I was testing with different versions of Visual Studio to try and 
>> nail down the source of a deprecation warning. I was using the 
>> --with-tools-dir config option to quickly switch between 
>> installations but noticed the VS install that was being found through 
>> that method was being discarded, leading to a failed configuration.
>>
>> The fix is pretty simple: 
>> http://cr.openjdk.java.net/~jvernee/vs_tools_dir/webrev.00/
>>
>> The TOOLCHAIN_CHECK_POSSIBLE_VISUAL_STUDIO_ROOT macro sets the 
>> VS_ENV_CMD  var, and skips doing anything when it is already set. So, 
>> previously, by setting it to an empty string _after_ the check for 
>> --with-tools-dir any VS install that's found with that method is 
>> always discarded, or otherwise overwritten when another method for 
>> finding a VS installation also works.
>>
> Looks good, thanks for fixing it!
>> With that fix selecting the VS installation works as expected.
>>
>> On a side note; I noticed that the hostx86 toolchain is preferred 
>> over the hostx64 version in VS 2017+, due to the order of values in 
>> VCVARSFILES in TOOLCHAIN_CHECK_POSSIBLE_VISUAL_STUDIO_ROOT. Is there 
>> any particular reason for this? I'd expect the x64 toolchain would be 
>> preferred on x64 platforms.
>>
> Hm, I think I agree. I'm probably responsible for that choice and I 
> think I was just trying to be conservative with changes. Would you 
> mind changing it and see if it has any effect on performance?
>
> /Erik
>
>> Jorn
>>