[LLVMdev] Getting a named value in llvm-c

[Bill Hart]

I understand the logic of that. Thanks.

I guess what I was imagining was a function:

LLVMValueRef LLVMGetValueByName(LLVMBuilderRef B, const char * Name);

That would be sufficient to completely separate the code I use to
handle the "back end", from the rest of my interpreter. A minor
elegance I can live without I guess.

Bill.

On 22 November 2012 08:31, Duncan Sands <baldrick at free.fr> wrote:
> Hi Bill,
>
>
> On 22/11/12 01:52, Bill Hart wrote:
>>
>> That's what I am doing of course, It;s just odd that I can get a
>> global by name but not a local.
>
>
> actually it's not that odd, since globals variables can be accessed by name
> from other compilation units, while local variables cannot.
>
> Ciao, Duncan.
>
>
>>
>> Bill.
>>
>> On 21 November 2012 09:35, Duncan Sands <baldrick at free.fr> wrote:
>>>
>>> Hi Bill,
>>>
>>>
>>>> I am wondering if there is a way to get a value by name in the C
>>>> interface for the LLVM Jit?
>>>
>>>
>>>
>>> since a Value includes simple constants like 42 that have no name, this
>>> is
>>> not possible in general.  Moreover names are usually optional and have no
>>> real meaning: they are just there to make the IR easier to read (an
>>> exception
>>> being struct type names).
>>>
>>> Perhaps you could maintain a map from name to Value* in your front-end?
>>>
>>> Ciao, Duncan.
>>>
>>>>
>>>> There seems to be a way to name values consistently, but no way to
>>>> retrieve those LLVMValueRef's by name.
>>>>
>>>> I see it is possible to get a struct by name and a type by name and a
>>>> function by name, and a few other esoteric things, but not a general
>>>> value.
>>>>
>>>> The reason I am wanting this is that I am writing a language where
>>>> there is a separation between the back end and the code which
>>>> processes the AST. In particular, I do not have any LLVM values or
>>>> types in the AST nodes themselves, only strings naming those values
>>>> and types. When the back end processes the AST it looks up the
>>>> relevant types and values by string name.
>>>>
>>>> The specific circumstance where this causes an issue is with
>>>> allocating local variables. The back end code needs to access such
>>>> variables at points different from where they were defined. At present
>>>> I have to store the relevant LLVMValueRef's in the AST or in some
>>>> other type information elsewhere in my implementation, rather than
>>>> store a string name and look them up as needed.
>>>>
>>>> Bill.
>>>> _______________________________________________
>>>> LLVM Developers mailing list
>>>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>>>
>>>
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>