[llvm-dev] Issues porting intrinsics to LLVM 10

[David Jones via llvm-dev]

Thanks - I was able to get past this problem.

For the benefit of anyone googling a similar problem after me:

I had to fix two separate problems:

1. Because intrinsic enum definitions are split out into target-specific
includes, I needed to name my intrinsics properly.

The target splitter assumes that intrinsics of the form "llvm.foo..." go
into "IntrinsicsFoo.h". For this to work, "foo" must be a known target.

In my case, I was extending the RISCV instruction set with an intrinsic
named "int_idaho_mt_begin".  Since "idaho" is not a valid target, I needed
to rename to "int_riscv_idaho_mt_begin". Note that doing so may require
changes to both include/llvm/IR/IntrinsicsXXX.h and
lib/Target/XXX/XXXInstrInfo.td (or some file referenced by it).  You will
also have to update any front ends to use the new names.

2. RISCVGenGlobalISel.inc is included from RISCVInstructionSelector.cpp.
Since this file does not already reference intrinsic definitions, the
include needed to be added there. The full path relative to your build
directory is required:

#include "llvm/IR/IntrinsicsRISCV.h"

With these changes I was able to generate code using my intrinsics with
LLVM 10.


On Wed, May 6, 2020 at 2:19 PM Krzysztof Parzyszek <kparzysz at quicinc.com>
wrote:

> Intrinsic headers have been broken up into smaller files.  Now you need to
> include the target-specific intrinsic header, e.g. IntrinsicsRISCV.h.
>
>
>
> --
>
> Krzysztof Parzyszek  kparzysz at quicinc.com   AI tools development
>
>
>
> *From:* llvm-dev <llvm-dev-bounces at lists.llvm.org> *On Behalf Of *David
> Jones via llvm-dev
> *Sent:* Wednesday, May 6, 2020 1:08 PM
> *To:* llvm-dev <llvm-dev at lists.llvm.org>
> *Subject:* [EXT] [llvm-dev] Issues porting intrinsics to LLVM 10
>
>
>
> I am maintaining proprietary extensions to the RISCV backend for our
> custom application.
>
>
>
> I have defined intrinsics for many of the custom instructions.  Against
> LLVM 7 this was working well.
>
>
>
> When I try to merge my changes into LLVM 10, I get:
>
>
>
> /home/dej/work/llvm_git/llvm-project/llvm/build/lib/Target/RISCV/RISCVGenGlobalISel.inc:11582:60:
> error: ‘idaho_mt_begin’ is not a member of ‘llvm::Intrinsic’
>          GIM_CheckIntrinsicID, /*MI*/0, /*Op*/0, Intrinsic::idaho_mt_begin,
>
>
>
> This intrinsic is defined pretty simply:
>
>
>
> let TargetPrefix = "idaho" in {
> def int_idaho_mt_begin : Intrinsic<[], [llvm_ptr_ty,llvm_i64_ty], []>;
>
> }
>
>
>
> With LLVM 7, I notice that build/include/llvm/IntrinsicEnums.inc contains
> an entry for each intrinsic in the system.  This is no longer the case for
> LLVM 10: there are only 277 definitions in the file. It seems that LLVM 10
> imposes some filter condition where it deems inclusion in the
> IntrinsicEnums.inc unnecessary.
>
>
>
> The other thing I notice: GlobalISel was not built (by default) in LLVM 7,
> but it is for LLVM 10.  This is the entity referencing the enums.
>
>
>
> I tried renaming my intrinsics to replace "idaho" with "riscv" speculating
> that this was the filtering condition, but that did not make any difference.
>
>
>
> What has changed?
>
>
>
>
>
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