[flang-dev] [RFC] Frontend driver: action vs non-action options

Andrzej Warzynski via flang-dev flang-dev at lists.llvm.org
Tue Oct 19 11:31:47 PDT 2021

We would like Flang's driver to be a drop-in replacement for e.g. 
`gfortran`. If we change this particular behaviour, we will be making 
the transition for our users harder.


On 19/10/2021 17:27, Peter Steinfeld wrote:
> You are correct.
> And from your example, it looks like changing this behavior for clang might not be worth the effort.
> But we're just starting out with flang.  I personally would opt for more error checking in flang's option specifications.  I don't know enough about how options processing is implemented to know how difficult it would be to make flang's behavior different from clang's.
> Pete
> -----Original Message-----
> From: Michael Kruse <llvm at meinersbur.de>
> Sent: Tuesday, October 19, 2021 9:10 AM
> To: Peter Steinfeld <psteinfeld at nvidia.com>
> Cc: Andrzej Warzynski <andrzej.warzynski at arm.com>; Michael Kruse <llvm at meinersbur.de>; flang-dev at lists.llvm.org
> Subject: Re: [flang-dev] [RFC] Frontend driver: action vs non-action options
> External email: Use caution opening links or attachments
> Am Do., 14. Okt. 2021 um 16:21 Uhr schrieb Peter Steinfeld
> <psteinfeld at nvidia.com>:
>> I think that this should apply to options generally, not just action options.
> This may break build systems that assume you can do that. E.g. user options are just appended to the command line allowing to override any flags that the build system has set.
> When compiling clang, the command line generated by CMake contains
> cc  ... -DNDEBUG  -UNDEBUG
> Michael

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