running intrinsics from C code

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1

I’ve created an intrinsic from my target, but I can’t figure out how I can run it from a C code. Most of the targets have a GCCBuiltin and it looks like it is the way to execute an intrinsic from C code. However in my case there is no actual GCC built in.

Any help on this is really appreciated.

2

GCCBuiltin just gives it a name for clang to lookup. Generally they match up with builtins that gcc also implements, but that’s not a requirement.

If you add a builtin with the same name to the builtin file in clang’s include/clang/Basic/Builtins*.def then they will find each other.

You can also just add a builtin to clang’s builtin file and catch it in clang’s lib/CodeGen/CGBuiltins.cpp and implement whatever IR you want including calling an intrinsic.

Hope this helps.

3

Thanks for the tip. For some reason it didn’t work. I’m sure I’m missing something very simple. Do you mind helping out? Here is what I have so far:

I’m getting a following error when I run a simple test:
cannot compile this builtin function yet

Here is the test code:

typedef int v4si attribute ((vector_size (16)));

int foo (int a, int b, int c, int d) {
v4si vec = {a, b, c, d};
return esencia_hadd(vec);
}

My intrinsic is defined in /include/llvm/IR/IntrinsicsEsencia.td

let TargetPrefix = “esencia” in
def int_esencia_hadd : Intrinsic<[llvm_i32_ty],
[llvm_v4i32_ty],
[IntrNoMem]>;

My builtin is defined in /include/clang/Basic/BuiltinsEsencia.def

BUILTIN(esencia_hadd, “iV4Si”, “nc”)

I’ve also added code to <full path to clang/lib/Basic/Targerts.cpp

const Builtin::Info EsenciaTargetInfo::BuiltinInfo = {
#define BUILTIN(ID, TYPE, ATTRS) { #ID, TYPE, ATTRS, 0, ALL_LANGUAGES },
#define LIBBUILTIN(ID, TYPE, ATTRS, HEADER) { #ID, TYPE, ATTRS, HEADER,
ALL_LANGUAGES },
#include “clang/Basic/BuiltinsEsencia.def”
};

as well as to /include/clang/Basic/TargetBuiltins.h

/// \brief Esencia builtins
namespace Esencia {
enum {
LastTIBuiltin = clang::Builtin::FirstTSBuiltin-1,
#define BUILTIN(ID, TYPE, ATTRS) BI##ID,
#include “clang/Basic/BuiltinsEsencia.def”
LastTSBuiltin
};
}

What am I missing?