riscv-nuclei-elf-gcc: do not fail on "-masm=att"

[vazhnov]

Hello!

I'm not sure this is correct project to ask this feature.

I use workstation with GNU/Linux and x86_64 architecture.
I use vim + vim-syntastic for syntax and style checks.
I use riscv-nuclei-elf-gcc from package toolchain-gd32v from PlatformIO:

 % riscv-nuclei-elf-gcc --version
riscv-nuclei-elf-gcc (GCC) 9.2.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

I faced with an issue: when I use riscv-nuclei-elf-gcc instead of system gcc, I receive an error message:

syntastic: 0.575801: checker output: [‘gcc: error: unrecognized command-line option ‘-masm=att’’, '']

This option, -masm=att came from this code https://github.com/vim-syntastic/syntastic/blob/master/syntax_checkers/asm/gcc.vim#L44 :

'main_flags': '-x assembler -fsyntax-only' . (g:syntastic_asm_generic ? '' : ' -masm=' . s:GetDialect(buf)) })

Is it possible to ignore this option, -masm=att, and not fail?

[jim-wilson]

The x86 toolchain has two incompatible assembly syntaxes: att and intel. So this is useless for RISC-V. You should look at the sources and figure out how to change it so that it always uses the generic asm syntax for RISC-V so that it never uses the -masm option.

[vazhnov]

When I created this issue, I thought RISC-V syntax uses AT&T syntax. I thought all assemblers are divided to AT&T and Intel syntax (for example, by different parameters order).

Now I see from this table, RISC-V syntax is not a part of AT&T syntax: it uses the same parameters order (source before the destination), but doesn't use prefix "$" for immediate values.

@jim-wilson , Am I right?

[aswaterman]

I'd just call it "RISC-V syntax". No $ on register specifiers; operand order is normally dest, src.

[vazhnov]

Thank you!