bscarlet
commented
9 years ago That error indicates you tried to construct a pointer type which is not valid; there are a few types X for which (pointer to X) is not valid in llvm IR.
http://llvm.org/doxygen/Type_8cpp_source.html#l00765
I'd guess the most likely case is that you're trying to make a pointer to void. In llvm IR you should use i8* or i64* or whatever's appropriate.
Since LLVM asserts at these points, rather than throwing or some such, a backtrace would be hard. There is a verification pass, which you can apply with LLVM.General.Analysis.verify, but it can't catch errors of construction like this one.
llvm-general uses FFI to C++ code because it gives you access to more of LLVM than generating textual IR. It does the Haskell-IR to C++ IR (and back) in particular using the C++ API instead of serialized IR to avoid adding unnecessary overhead. For applications involving intensive optimization passes, that overhead is often irrelevant; but for others (e.g. haskell generation of small LLVM snippets for JIT) it can be more important.
I would like to build a second Haskell-only serializer/deserializer pair in llvm-general-pure (and QuickCheck them against the C++ versions), so that a Haskell project could opt out of linking in the LLVM libraries entirely if it just wanted to generate textual IR to pass to LLVM in another process.
tinco
Hi,
I ran into this exception, and I'm not certain what causes it:
Assertion failed: (isValidElementType(EltTy) && "Invalid type for pointer element!"), function get, file Type.cpp, line 732.
I think I had this same exception a couple of months ago, and back then I found a solution to it. But now it happened again and I forgot what the problem last time was. I suppose somewhere my code tries to dereference a pointer to something that's not a valid pointer element. But I get no information about what that element type is, no backtrace either.
Is there a way to get more information?
As an aside, why is this C++ code? This is just IR code generation right? Perhaps we can work something out to do this in pure Haskell, or do you feel IR is so complicated it would be a lot of work?