[Flang-dev] [llvm-dev] RFC: Adding debug information to LLVM to support Fortran

Eric Schweitz (PGI) eric.schweitz at pgroup.com
Mon Nov 5 12:59:25 EST 2018

Hi John,

Thanks for the feedback.  Glad that this might have broader usefulness.

We've obviously been focused on Fortran implementations, but we're not against generalizing.


-----Original Message-----
From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of John Reagan via llvm-dev
Sent: Friday, November 02, 2018 2:34 PM
To: llvm-dev at lists.llvm.org
Subject: Re: [llvm-dev] RFC: Adding debug information to LLVM to support Fortran

We use DW_TAG_string_type on OpenVMS I64 for Fortran CHARACTER*n, Pascal's PACKED ARRAY OF CHAR, COBOL, etc.  We'll want it as well.  I had sorta assumed it was already there?

For arrays with run-time bounds, we have them too in Pascal (they are called "Schema Types" in the Extended Pascal standard).  I'd prefer that
you pick a more generic name than "DIFortranSubrange"   Again on OpenVMS
I64, we support bounds as subranges with literals, simple locations, or thunk calls (as Pascal's computation of array bounds or size can get complicated with uplevel referencing in the mix - we didn't want to have to describe how to walk the static link in a location expression)

And Fortran's assumed shape arrays is exactly mapped to an OpenVMS descriptor format (we have several) so we'll use these as well for non-Fortran too.

Other than suggesting to make the names less Fortran specific (the folks looking at adding PL/1 support would probably want to leverage all of this, Ada too if somebody tackles that), I'm OK with the approach.


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