llvm dev - Dec 2012 - [LLVMdev] [MC] [llvm-mc] Getting target specific information to <target>ELFObjectWriter

On Tue, Dec 11, 2012 at 2:48 PM, Carter, Jack <jcarter at mips.com>
wrote:
> Attached are the promised patches for the below proposed change.
>
Just a quick question from an initial review: isn't the int->bool
mapping of flags a bit limiting. Flag can have actual values and not
only be there or not be there. Wouldn't a more generic mapping
(string->string ?) be more universally useful? Or am I missing
something obvious here...

Eli

Eli,

This is the kind of feedback I want. I believe I have to add to the base class
so it should be generally useful. I can see string being better for the value. I
still am enamoured with an enumeration for the tab though: int->string. How
would that be a limitation?

How about the rest of the patch? 

I appreciate the feedback,

Jack
________________________________________
From: Eli Bendersky [eliben at google.com]
Sent: Friday, December 14, 2012 11:35 AM
To: Carter, Jack
Cc: Jim Grosbach; List
Subject: Re: [LLVMdev] [MC] [llvm-mc] Getting target specific information to
<target>ELFObjectWriter

On Tue, Dec 11, 2012 at 2:48 PM, Carter, Jack <jcarter at mips.com>
wrote:
> Attached are the promised patches for the below proposed change.
>
Just a quick question from an initial review: isn't the int->bool
mapping of flags a bit limiting. Flag can have actual values and not
only be there or not be there. Wouldn't a more generic mapping
(string->string ?) be more universally useful? Or am I missing
something obvious here...

Eli

On Fri, Dec 14, 2012 at 1:03 PM, Carter, Jack <jcarter at mips.com>
wrote:
> Eli,
>
> This is the kind of feedback I want. I believe I have to add to the base
class so it should be generally useful. I can see string being better for the
value. I still am enamoured with an enumeration for the tab though:
int->string. How would that be a limitation?
>
I guess that's fine, as long as you don't just limit it to binary
"has
/ hasn't flag".
> How about the rest of the patch?
>
There's one thing about it I'm not sure I understand. You are
essentially passing commands to the assembler via "target"
information. But how does this make sense? I realize that the flags
themselves (their kinds and possible values) are properties of the
target, but their passing to the assembler is not. In other words, I
would expect the assembler driver to propagate flags down to the ELF
writer in some manner which is not through the target object. The
target object is supposed to provide information about the target,
which does not depend on the particular invocation of the assembler
and the flags passed to it.

I hope the above is coherent; it not, feel free to demand another attempt.

Eli