llvm dev - Jun 2010 - [LLVMdev] Adding fields in a already built type? (2)

> Nope, types are immutable once created.  The only thing you can do is
"refine" opaque types to other types.  There is a section in the
programmer's manual on this:
> http://llvm.org/docs/ProgrammersManual.html#TypeResolve
> 
> -Chris

So I succeeded  in using a "PATypeHolder" for the "opaque"
type, define a Type* with PointerType::getUnqual, prepare a field,  then use
" refineAbstractTypeTo " to built the real type with this added field.

The thing is that I would need to do that repeatedly, that is progressively
adding fields, generates code that access those ready fields, and
"refine" the type step by step.

Is that even possible?

Thanks

Stéphane Letz

On Jun 15, 2010, at 11:51 AM, Stéphane Letz wrote:
>> Nope, types are immutable once created.  The only thing you can do is
"refine" opaque types to other types.  There is a section in the
programmer's manual on this:
>> http://llvm.org/docs/ProgrammersManual.html#TypeResolve
>> 
>> -Chris
> 
> 
> So I succeeded  in using a "PATypeHolder" for the
"opaque" type, define a Type* with PointerType::getUnqual, prepare a
field,  then use " refineAbstractTypeTo " to built the real type with
this added field.
> 
> The thing is that I would need to do that repeatedly, that is progressively
adding fields, generates code that access those ready fields, and
"refine" the type step by step.
> 
> Is that even possible?
It would work, but sounds really inefficient.  What are you really trying to do
here?

-Chris

Le 15 juin 2010 à 21:14, Chris Lattner a écrit :
> 
> On Jun 15, 2010, at 11:51 AM, Stéphane Letz wrote:
> 
>>> Nope, types are immutable once created.  The only thing you can do
is "refine" opaque types to other types.  There is a section in the
programmer's manual on this:
>>> http://llvm.org/docs/ProgrammersManual.html#TypeResolve
>>> 
>>> -Chris
>> 
>> 
>> So I succeeded  in using a "PATypeHolder" for the
"opaque" type, define a Type* with PointerType::getUnqual, prepare a
field,  then use " refineAbstractTypeTo " to built the real type with
this added field.
>> 
>> The thing is that I would need to do that repeatedly, that is
progressively adding fields, generates code that access those ready fields, and
"refine" the type step by step.
>> 
>> Is that even possible?
> 
> It would work, but sounds really inefficient.  What are you really trying
to do here?
> 
> -Chris

inefficient : do you mean because all users of the refined type would have to be
"notified" ?

The reason is that our code generator generates a struct (progressively adding
fields) and generates code that access this struct (that is : the fields that
are already added). If we cannot create the struct progressively, then we have
to define a pass to build the complete struct, then define a second pass to
generate the code. If we can simply create the struct progressively at LLVM
level, then it make our code simpler.

Thanks

Stéphane Letz