[PATCH] D45284: [RISCV] More validations on the input value of -march=

[Alex Bradbury via Phabricator via cfe-commits]

asb added a comment.

In https://reviews.llvm.org/D45284#1074282, @apazos wrote:

> Hi Alex, it seems the table expects these extensions in a canonical order too: all x extensions, followed by all s extensions, and then all sx extensions.
>
> I can make the change, no problem. I have also coded other error situations described below.
>
> But f I cannot push a test we can enable, because we error out when we find the first non-supported extension in the string with unsupported extension message, and stop parsing the string.


In the best case we would first parse the string and give errors based on the string being malformed before determining which extensions the compiler supports and complaining if the extension is not supported. This would probably move us towards a two-pass scheme where structs are are generated from the string, (parsing stage) which are then processed. e.g. `{ enum ExtType Type; StringRef name; int MajorVersion; int MinorVersion; }`. The parser can issue errors encountered when extracting this struct (e.g. malformed version identifiers), including erroring if the ordering of the ExtType relative to the previous ExtType is unexpected. The next step is complaining about semantic issues (clashing extensions or extensions with missing dependencies) as well as extensions that aren't supported.

However I realise that might be a larger refactoring. This is already the most complete RISC-V ISA string parser in existence (as far as I know), which goes some way beyond our near-term requirements. I'd be happy to merge this current version and evolve it in-tree if you prefer, or of course I'll happily review further updates to this patch.


https://reviews.llvm.org/D45284