[LLVMdev] Binutils and LLVM - gathering information

[Michael Spencer]

On Tue, Nov 6, 2012 at 2:19 PM, Marshall Clow <mclow.lists at gmail.com> wrote:
> Binutils and LLVM
>
> As part of "owning our own toolchain", various people have expressed an interest and have been working on creating various tools that duplicate the functionality of tools available on other systems.
>
> As a start, I'd like to summarize the current status, and ask people for help updating the list.
>
> List taken from <http://www.gnu.org/software/binutils/>
>
> ==============
>
> * ld (linker) -- lld is under active development
>
> * as (assembler) -- There is llvm-as, but it appears to be an assembler for LLVM bitcode.
>
> * addr2line (Converts addresses into filenames and line numbers) -- ????
>
> * ar (creates, modifies and extracts from archives) -- llvm-ar <http://llvm.org/docs/CommandGuide/llvm-ar.html> appears to do this for bitcode, object and archive files.

This will need major changes to handle integrating ranlib.

>
> * c++filt (demangles encoded C++ symbols) -- this facility is built into libcxxabi, but I don't know of a tool that brings this out to the command-line.
>
> * dlltool (Creates files for building and using DLLs) -- ????
>
> * gprof (Displays profiling information) -- ????
>
> * nlmconv (Converts object code into an Netware Loadable Module) -- ????

I really don't think we care about this.

>
> * nm (Lists symbols from object files) -- llvm-nm does this for bitcode, object and archive files.
>
> * objcopy (Copies and translates object files) -- ???

This one is hard, as translating object files between formats doesn't
really make sense with modern formats. I believe the main
functionality people use is converting object files to flat binaries.

>
> * objdump (Displays information from object files) -- llvm-objdump appears to do this for bitcode, object and archive files.
>
> * ranlib (Generates an index to the contents of an archive) -- There is an llvm-ranlib, but the docs at  <http://llvm.org/docs/CommandGuide/llvm-ranlib.html> say that it only indexes bitcode files.

Yep, needs object support.

>
> * readelf (Displays information from any ELF format object file) -- ????

llvm-readobj outputs the same format as readelf.

>
> * size (Lists the section sizes of an object or archive file) -- llvm-size does this for bitcode, object and archive files.
>
> * strings (Lists printable strings from files) -- I have written a program named llvm-strings that does this, and will be submitting it as a patch shortly.
>
> * strip (discards symbols) -- ????
>
> * windmc (A Windows compatible message compiler) -- ????
>
> * windres (A compiler for Windows resource files) -- ????

These two aren't high priority, but they are needed for a lot of MFC GUI code.

>
> I'd appreciate if people with more knowledge than myself could chime in with updates to this list.
>
> Thanks!
>
> -- Marshall

So far we have solved naming collisions by making the tool work with
multiple formats, however I don't feel that is the right solution for
llvm-as. llvm-as/llvm-dis are very simple core tools for converting
between ir formats. Extending this to object code assembly feels
wrong.

I think the solution to this is to move the llvm developer only tools
(llc, lli, opt, as, dis, bugpoint, bcanalyzer, diff, extract, link) to
the llvm tool. This would have a git like interface for accessing the
subtools. The other tools remain as user tools and still support
bitcode.

- Michael Spencer