----- Mensaje original ----
De: Benjamin Smedberg <benjamin at smedbergs.us>
Para: LLVM Developers Mailing List <llvmdev at cs.uiuc.edu>
Enviado: viernes, 22 de febrero, 2008 22:36:40
Asunto: Re: [LLVMdev] Calling functions
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Álvaro Castro wrote:
| Hello!
|
|
| I'm trying LLVM for generating code and I found something I
cannot figure
out or find in the documentation:
|
| I'm doing something like this to call "sin" from std:
|
| std::vector<const Type*> params;
| params.push_back( Type::FloatTy );
| FunctionType *FT = FunctionType::get( Type::FloatTy, params, false);
| Function *F = new Function( FT, Function::ExternalLinkage,
"sin", M );
| CallInst *CallExternal = new CallInst( F, SomeValue,
"external_call", BB );
|
|
| I can make some calls to functions like glclear() as I'm using
opengl:
| ...
| Function *F = new Function( FT, Function::ExternalLinkage,
"glclear", M );
| ...
|
| But if I want to call any function inside a C++ namespace I
don't find the
way to do it. Imagine you want to call
|
| othernamespace::globalFunction()
See this older message:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2007-December/011616.html
*************************
It seems that the previous message was sent with some corruption, sorry for it.
It it happens again I'll use another e-mail.
Thanks for your reply, Benjamin.
I've tried that approach to the c++ function calls. I ended up with this
code:
#######
float test( float input )
{
return 0.0;
}
[...]
typedef float (*P_FUNCTION) ( float );
P_FUNCTION pt2Function = &test;
intptr_t functionInt = (intptr_t)pt2Function;
Constant *functionConstant = ConstantInt::get( APInt( sizeof(intptr_t),
functionInt) );
const Type *ArgTy = Type::FloatTy;
PointerType* arg = PointerType::get( ArgTy, 0 );
functionConstant = ConstantExpr::getIntToPtr( functionConstant, arg );
[...] (BB and CoefficientOne definition and other stuff)
CallInst *CallExternal = new CallInst(functionConstant, CoefficientOne,
"external_call", BB );
CallExternal->setTailCall();
#######
The runtime error was:
/var/tmp/portage/sys-devel/llvm-base-2.2/work/llvm-2.2/include/llvm/Support/Casting.h:199:
typename llvm::cast_retty<To, From>::ret_type llvm::cast(const Y&)
[with X = llvm::FunctionType, Y = const llvm::Type*]: Assertion
`isa<X>(Val) && "cast<Ty>() argument of incompatible
type!"' failed.
I must admit I used AddressSpace = 0, but I have no idea of what to put there. I
don't understand such a problem of types, as everything is a float except
the integer holding the function address. I suppose the problem is elsewhere.
Thanks a lot for your help.
.alvaro.castro.
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