[llvm-dev] Fwd: Writing simple intrinsic in clang (original) (raw)

Павел Безбородов via llvm-dev llvm-dev at lists.llvm.org
Wed Sep 26 01:30:53 PDT 2018

Actually, I've done it, but I have problem with Intrinsic namespace, while adding my intrinsic to CodeGenFunction::EmitMyTargetBuiltinExpr I do something like CGF.getIntrinsic(Intrinsic::my_builtin) and it throws error /tools/clang/lib/CodeGen/CGBuiltin.cpp:10327: error: no member named 'arc_sub4' in namespace 'llvm::Intrinsic' llvm::Function *F = CGM.getIntrinsic(Intrinsic::arc_sub4); ~~~~~~~~~~~^ I don't know how to fix this. I'm new to LLVM and need some help in it...

вт, 25 сент. 2018 г. в 21:12, Friedman, Eli <efriedma at codeaurora.org>:

On 9/24/2018 6:47 AM, Павел Безбородов via llvm-dev wrote: > I want to write a simple backend-specific instrinsic that will just > call an instruction. How should I do that?

Is this really not documented anywhere...? Anyway, the basic steps: 1. Add the builtin to the list of intrinsics for your target: include/llvm/IR/IntrinsicsYourTarget.td. Use a GCCBuiltin for the corresponding C intrinisc name. 2. Teach your target to lower the intrinsic to an instruction; you can usually just use the name of the intrinsic in a pattern in lib/Target/YourTarget/YourTargetInstrInfo.td. 3. Add the builtin to include/clang/Basic/BuiltinsYourTarget.def An example of an intrinsic implemented this way is intarmqadd8 in the _ARM backend (corresponding to the C builtin builtinarmqadd8); it should be straightforward to follow that example. This approach assumes your intrinsic is simple: it returns at most one value, and all the parameter and return types are legal. If that isn't true, you might need to write some C++ code to handle it in clang or in your backend. Maybe we should add this as a section to http://llvm.org/docs/WritingAnLLVMBackend.html . -Eli -- Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20180926/fd46870a/attachment.html>

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