[Info-vax] CRTL and RMS vs SSIO

[Arne Vajhøj]

On 10/16/2021 5:36 PM, Lawrence D’Oliveiro wrote:
> On Sunday, October 17, 2021 at 12:35:10 AM UTC+13, John Dallman wrote:
>> In article <44512ead-b6e0-4735... at googlegroups.com>,
>> lawren... at gmail.com (Lawrence D_Oliveiro) wrote:
>>
>>> If VMS compatibility for user-mode code just takes the form of a
>>> library to link against, then VMS-specific compilers shouldn_t be
>>> necessary. You could use the existing GNU and LLVM compilers, and
>>> just implement wrappers that understand the VMS-specific options.
>>
>> Won't work without ludicrous amounts of effort.
> 
> The question is whether that effort is more or less than that of
> porting the whole of VMS, with its deeply-embedded hardware
> assumptions dating back to VAX days, to new hardware. I suspect it’s
> a lot less.
Yes. But everybody else including those doing the actual think
otherwise.

>> The reasons for wanting to use the DEC compiler front-ends is that DEC
>> languages weren't terribly standards-conformant: once upon a time, the
>> DEC market was big enough that the company didn't worry too much about
>> those things. It isn't just additional command-line options, it's
>> differences in the languages and libraries. Providing Clang for C++ and
>> standard-conformant C is an addition: the DEC C will still be needed for
>> historical code.
> 
> You have the source for those GCC and LLVM compilers, that you can
> adapt as necessary. Plus you have the source for DEC’s own
> proprietary compilers, that can also be adapted as necessary.

GCC is a no go due to GPL.

They are doing that with LLVM. Existing frontend, some existing
layers in the middle and LLVM at the backend. Because the customers
need the extensions.

Arne