[PATCH] Support native mach-o names in MachOFormat.h

[Charles Davis]

On Aug 26, 2013, at 3:27 PM, Nick Kledzik wrote:

> Chip,
> 
> I talked to Michael Spencer and Jim Grosbach off-list and they both think switching Support/MachO.h to use the documented mach-o names is a good idea.   You said you’ve been sitting on the patch a while.  What has been holding you back from getting the patch in?
There were some patches ahead of it in my local Git tree, which makes it difficult to use git svn dcommit on it (at least, until I realized I could just put it and patch #2 into a separate branch and commit from that).
>  I’d like it to go in, to help me with my lld work.
Would you like me to commit them now?

Chip

> 
> -Nick
> 
> On Aug 19, 2013, at 3:54 PM, Charles Davis <cdavis5x at gmail.com> wrote:
>> On Aug 19, 2013, at 4:22 PM, Nick Kledzik wrote:
>> 
>>> Wow, that was fast Charles!
>> Yeah, I've been sitting on those patches for a while.
>>> 
>>> I did not know that Support/MachO.h even existed!
>> Outside of LLDB, hardly anyone does. They added it, and AFAIK they're the only ones that use it right now. (These patches will obviously change that.)
>>> Why does Object/MachOFormat.h and it both define the same things differently?
>> I don't know, and that's why I wanted to get rid of one. I suspect that whoever added Object/MachOFormat.h probably didn't know about Support/MachO.h either.
>>>  There was some recent changes to ELF headers to layer them.  Is there something analogous we need to do for mach-o?
>> We used to do something similar--we had the MachOObject class that does about the same thing as the ELFFile class (i.e. it was a low-level interface to a Mach Object), except without the heavy template meta-programming. MachOObjectFile was then just a thin wrapper around it, just as ELFObjectFile is now just a wrapper around ELFFile. But Rafael Espíndola got rid of that a while back, saying something about the InMemoryStruct template not working right. (He also wanted to add the kind of template meta-programming to Mach-O that ELF was using for its structs, but that got shot down.)
>> 
>> Chip
>> 
>>> 
>>> -Nick
>>> 
>>> On Aug 19, 2013, at 3:14 PM, Charles Davis <cdavis5x at gmail.com> wrote:
>>>> On Aug 19, 2013, at 4:02 PM, Eric Christopher wrote:
>>>> 
>>>>> Probably wouldn't take much to fix up all the name uses and leave out
>>>>> the conditional?
>>>> I have two patches; one does what Nick's patch does, but to <llvm/Support/MachO.h>, and also updates everything using it in LLVM to use the new names, and one that strips out the now-redundant <llvm/Object/MachOFormat.h> header and changes everything using *that* to use the new names.
>>>> 
>>>> Chip
>>>> <0001-Support-MachO-Add-a-bunch-of-defines.patch><0002-Move-everything-depending-on-Object-MachOFormat.h-ov.patch>
>>>> 
>>>>> 
>>>>> -eric
>>>>> 
>>>>> On Mon, Aug 19, 2013 at 2:57 PM, Nick Kledzik <kledzik at apple.com> wrote:
>>>>>> [+patch]
>>>>>> 
>>>>>> include/llvm/Object/MachOFormat.h is odd in that it makes up new names for the public mach-o format structs and constants (e.g. it defines LCT_Segment instead of LC_SEGMENT). LLVM does not handle ELF this way.  LLVM defines SHT_PROGBITS just like the standard ELF header (although llvm puts them into a namespace).  This current set up makes it hard to reconcile the public mach-o documentation with llvm source code.
>>>>>> 
>>>>>> This patch adds all the standard mach-o names for structs and constants in the llvm::object::mach_o namespace.  All the existing names remain, but I put them inside #ifndef LLVM_NO_OLD_MACH_O_NAMES, so that if someone wanted to switch to the standard names they could define LLVM_NO_OLD_MACH_O_NAMES, do a full build, and update whatever failures are seen.
>>>>>> 
>>>>>> This issue came up during a code review of lld, as to why lld was defining it own mach-o constants instead of using the ones in llvm.
>>>>>> 
>>>>>> -Nick
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> _______________________________________________
>>>>>> llvm-commits mailing list
>>>>>> llvm-commits at cs.uiuc.edu
>>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>>>>> 
>>>>> 
>>>>> _______________________________________________
>>>>> llvm-commits mailing list
>>>>> llvm-commits at cs.uiuc.edu
>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>