[llvm-dev] Subclassing LLVM Type

[Jajoo, Malhar via llvm-dev]

Hi Tim,


Thanks for that , I have read the documentation on this , but I would like to know
if it would be the right thing to do , ie , changing the enum within llvm::Type

and I'm slightly unclear on how I can update the C binding ?

Can someone kindly clarify that ?


Thanks,

Malhar

________________________________
From: 陳韋任 <chenwj.cs97g at g2.nctu.edu.tw>
Sent: Friday, June 9, 2017 11:29:26 PM
To: Tim Northover
Cc: Jajoo, Malhar; llvm-dev at lists.llvm.org
Subject: Re: [llvm-dev] Subclassing LLVM Type

This [1] might worth reading, Malhar.

[1] http://llvm.org/docs/HowToSetUpLLVMStyleRTTI.html
How to set up LLVM-style RTTI for your class hierarchy ...<http://llvm.org/docs/HowToSetUpLLVMStyleRTTI.html>
llvm.org
Background ¶ LLVM avoids using C++’s built in RTTI. Instead, it pervasively uses its own hand-rolled form of RTTI which is much more efficient and flexible ...




2017-06-10 4:12 GMT+08:00 Tim Northover via llvm-dev <llvm-dev at lists.llvm.org<mailto:llvm-dev at lists.llvm.org>>:
On 9 June 2017 at 12:03, Jajoo, Malhar via llvm-dev
<llvm-dev at lists.llvm.org<mailto:llvm-dev at lists.llvm.org>> wrote:
> Is there some way around this ( without suggesting a change to my entire AST ) ?

LLVM has its own lightweight dynamic casting infrastructure which the
Type hierarchy already makes use of.

You have to implement a "classof" function in your DummyType
definition. That means you'll need a new type ID. Appropriating an
unused one is slightly dodgy, but probably OK in practice if you're
careful.

After that you'd write "dyn_cast" instead of "dynamic_cast", since
that's what the LLVM version is called.

Cheers.

Tim.
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--
Wei-Ren Chen (陳韋任)
Homepage: https://people.cs.nctu.edu.tw/~chenwj
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