[llvm-commits] [PATCH] Asm operand parsing improvements

[Bruno Cardoso Lopes]

ping!

On Wed, Jan 26, 2011 at 11:21 AM, Bruno Cardoso Lopes
<bruno.cardoso at gmail.com> wrote:
> Hi,
>
> The first attached patch implements support for custom target specific
> asm parsing of operands. This is useful to avoid adding hacks to
> AsmParsers whenever something different from an immediate or register
> appears. The initial motivation was to remove the "mcr" family of
> hacks from ARMAsmParser, but this is also going to be useful for other
> ARM system instructions which I'm about to add the correct parsing and
> encoding once this gets accepted. The second attached patch contains
> modifications to the ARMAsmParser so that it starts using this
> mechanism.
>
> A quick explanation of how it works (read the first patch for details):
>
> A table like the one below is autogenerated for every instruction
> containing a 'ParserMethod' in its AsmOperandClass:
>
> static const OperandMatchEntry OperandMatchTable[20] = {
>  /* Mnemonic, Operand List Mask, Operand Class, Features */
>  { "cdp", 29 /* 0, 2, 3, 4 */, MCK_Coproc, Feature_IsThumb|Feature_HasV6 },
>  { "cdp", 58 /* 1, 3, 4, 5 */, MCK_Coproc, Feature_IsARM },
>
> A matcher function very similar (but lot more naive) to
> MatchInstructionImpl scans the table. After the mnemonic match, the
> features are checked and if the "to be parsed" operand index is
> present in the mask, there's a real match. Then, a switch like the one
> below dispatch the parsing to the custom method provided in
> 'ParseMethod':
>
>  case MCK_Coproc:
>    return TryParseCoprocessorOperandName(Operands);
>
> Ok to commit? Suggestions?
> Thanks.
>
> --
> Bruno Cardoso Lopes
> http://www.brunocardoso.cc
>



-- 
Bruno Cardoso Lopes
http://www.brunocardoso.cc