llvm dev - Oct 2017 - Creating arbitrary data type in LLVM IR

LLVM Type class offers pointers to known data types, e.g.
Type::getInt8PtrTy(), Type::getDoublePtryTy() etc. What if I need to get a
type representing a pointer to some arbitrary structure? How do I create
such pointer in IR?

The problem is not necessarily only with the pointer. If I need to create a
function in IR that accepts STL Map as an argument, how do I declare the
signature of such a function as well?

-- 

Thanks & Regards,
Dipanjan
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On 10 Oct 2017, at 09:59, Dipanjan Das via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
> LLVM Type class offers pointers to known data types, e.g.
Type::getInt8PtrTy(), Type::getDoublePtryTy() etc. What if I need to get a type
representing a pointer to some arbitrary structure? How do I create such pointer
in IR?
Once you have an llvm::Type, call its getPointerTo() method.  The argument is
the address space of the pointer - most of the time the default 0 will be
correct.
> The problem is not necessarily only with the pointer. If I need to create a
function in IR that accepts STL Map as an argument, how do I declare the
signature of such a function as well?
Getting an llvm::Type for a std::map is a *lot* harder, because the exact type
depends on your C++ standard library implementation and on the type of the
template parameters.  Your best bet is going to be to embed some of the clang
libraries and have them parse <map> for you and emit the specialisation
that you need.

David