[llvm-dev] Parse Instruction

[Sky Flyer via llvm-dev]

Hi Pierre-Andre

Thanks for your prompt reply.
What I mean, is located at line 4192
(http://code.woboq.org/llvm/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp.html#4192
).
It, first, has to parse the instruction, and based on the number of
operands it uses a pattern in MatchAndEmit.
My problem is, what would be a suitable substitute if operands in the
assembly code are not comma-separated, instead space-separated. (as you
know, space is automatically removed so I cannot simply switch
AsmToken::Comma to AsmToken::Space.)

Thanks a lot. :-)




On Mon, Sep 28, 2015 at 3:32 PM, Pierre-Andre Saulais <
pierre-andre at codeplay.com> wrote:

> Hi ES,
>
> From what I understand instruction parsing is divided into two parts:
>
> - Parsing an operand list (XXXAsmParser::ParseInstruction)
> - Turning the operand list into an actual instruction
> (XXXAsmParser::MatchAndEmitInstruction)
>
> The second part does the validation (e.g. how many operands, what kind,
> etc) while the first part only does the parsing. That's why I think in the
> first part you have to handle all possible operand combinations (i.e. parse
> the first operand, and keep parsing operands as long as you see spaces).
> LLVM will reject instructions with too many operands (as defined in the .td
> files).
>
> Is this something that would work with your assembly syntax?
>
> Cheers,
> Pierre-Andre
>
>
> On 28/09/15 14:21, Sky Flyer via llvm-dev wrote:
>
> practically I cannot use a function namly *getMnemonicAcceptInfo*
> (mnemonic as input, and number of possible outputs as output), because
> there are mnemonics that accepts different number of operands! :-/
>
> Any help is highly appreciated.
>
> On Mon, Sep 28, 2015 at 10:53 AM, Sky Flyer <skylake007 at googlemail.com>
> wrote:
>
>> Hi all,
>>
>> in most of the architectures, assembly operands are comma-separated.
>> I would like to parse an assembly code that is space-separated and I am
>> having a bit of problem.
>> In *ParseInstruction* function, I don't know what is the easiest way to
>> figure out how many operands a mnemonic expected to have.
>> In comma-separated assembly code, it just consuming commas (while
>> (getLexer().is(AsmToken::Comma))) and adds operands, but it's not the case
>> for space...
>>
>> I have a dirty hack, that I manually provide such information (number of
>> operands) in a function called for example getMnemonicAcceptInfo and with a
>> for loop I parse the operand!!
>>
>> What would you suggest for parsing space-separated assembly codes when it
>> comes to figuring out if a mnemonic has two operands or one?
>>
>> Cheers,
>> ES
>>
>
>
>
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