[RTEMS Project] #4623: Add RSB for LLVM targeting RTEMS

[RTEMS trac]

#4623: Add RSB for LLVM targeting RTEMS
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 Reporter:  Joel Sherrill                        |       Owner:  (none)
     Type:  enhancement                          |      Status:  new
 Priority:  normal                               |   Milestone:  Indefinite
Component:  tool                                 |     Version:
 Severity:  normal                               |  Resolution:
 Keywords:  llvm, tools, gcc, llvm, ecosystem,   |  Blocked By:
  SoC, large                                     |
 Blocking:                                       |
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Description changed by Joel Sherrill:

Old description:

> LLVM support for RTEMS has been included in the tools shipped by Gaisler
> (e.g. their RCC). RTEMS itself should now have all modifications needed
> to not be tied to GCC. This project is to add an RSB recipe to build an
> LLVM toolchain.
>
> Information from Daniel Hellstrom:
>
>   RCC-1.3 has not converted into using the RSB. However I believe we have
> upstreamed every change to the RTEMS kernel tree which was related to
> LLVM/Clang support for SPARC. The RCC-1.3 section 2.2.4 includes some
> information what is compiled with GCC in our LLVM toolchain:
>
>    * https://www.gaisler.com/anonftp/rcc/rcc-1.3/1.3.1/rcc-1.3.1.pdf
>
>    * https://www.gaisler.com/anonftp/rcc/rcc-1.3/1.3.1/sparc-
> rtems-5-llvm-8.0.0-1.3.1-linux.txz
>
>   For NOEL-V/RISC-V we only provide GCC toolchain today.
>
> After building the tools with the RSB, those tools must be used to build
> at least one BSP from an architecture which is not currently supported by
> LLVM. ARM, RISC-V, or x86_64 are likely first architectures to consider
> with testing on a BSP which can run on a simulator. Test results are
> necessary for GCC (baseline) and LLVM (objective).

New description:

 LLVM support for RTEMS has been included in the tools shipped by Gaisler
 (e.g. their RCC). RTEMS itself should now have all modifications needed to
 not be tied to GCC. This project is to add an RSB recipe to build an LLVM
 toolchain.

 Information from Daniel Hellstrom:

   RCC-1.3 has not converted into using the RSB. However I believe we have
 upstreamed every change to the RTEMS kernel tree which was related to
 LLVM/Clang support for SPARC. The RCC-1.3 section 2.2.4 includes some
 information what is compiled with GCC in our LLVM toolchain:

    * https://www.gaisler.com/anonftp/rcc/rcc-1.3/1.3.1/rcc-1.3.1.pdf

    * https://www.gaisler.com/anonftp/rcc/rcc-1.3/1.3.1/sparc-
 rtems-5-llvm-8.0.0-1.3.1-linux.txz

   For NOEL-V/RISC-V we only provide GCC toolchain today.

 After building the tools with the RSB, those tools must be used to build
 at least one BSP from an architecture which is not currently supported by
 LLVM. ARM, RISC-V, or x86_64 are likely first architectures to consider
 with testing on a BSP which can run on a simulator. Test results are
 necessary for GCC (baseline) and LLVM (objective).

 There are multiple tickets related to llvm. Finishing this project may
 close one or more of them. Any work on this ticket should see if the
 others need updating or closing.

 Possible Mentors: Gedare Bloom, Daniel Hellstrom, Chris Johns, Joel
 Sherrill
 Skills: C
 Difficulty: Medium

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Ticket URL: <http://devel.rtems.org/ticket/4623#comment:1>
RTEMS Project <http://www.rtems.org/>
RTEMS Project