[GHC] #9863: Provide PowerPC 64 bit native code generator

[GHC]

#9863: Provide PowerPC 64 bit native code generator
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        Reporter:  trommler         |                   Owner:
            Type:  feature request  |                  Status:  patch
        Priority:  normal           |               Milestone:  7.12.1
       Component:  Compiler         |                 Version:  7.8.3
      Resolution:                   |                Keywords:
Operating System:  Linux            |            Architecture:  powerpc64
 Type of failure:  None/Unknown     |               Test Case:
      Blocked By:                   |                Blocking:
 Related Tickets:                   |  Differential Revisions:  Phab:D629
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"d3c1dda60d0ec07fc7f593bfd83ec9457dfa7984/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="d3c1dda60d0ec07fc7f593bfd83ec9457dfa7984"
 Implement PowerPC 64-bit native code backend for Linux

 Extend the PowerPC 32-bit native code generator for "64-bit
 PowerPC ELF Application Binary Interface Supplement 1.9" by
 Ian Lance Taylor and "Power Architecture 64-Bit ELF V2 ABI Specification
 --
 OpenPOWER ABI for Linux Supplement" by IBM.
 The latter ABI is mainly used on POWER7/7+ and POWER8
 Linux systems running in little-endian mode. The code generator
 supports both static and dynamic linking. PowerPC 64-bit
 code for ELF ABI 1.9 and 2 is mostly position independent
 anyway, and thus so is all the code emitted by the code
 generator. In other words, -fPIC does not make a difference.

 rts/stg/SMP.h support is implemented.

 Following the spirit of the introductory comment in
 PPC/CodeGen.hs, the rest of the code is a straightforward
 extension of the 32-bit implementation.

 Limitations:
 * Code is generated only in the medium code model, which
   is also gcc's default
 * Local symbols are not accessed directly, which seems to
   also be the case for 32-bit
 * LLVM does not work, but this does not work on 32-bit either
 * Must use the system runtime linker in GHCi, because the
   GHC linker for "static" object files (rts/Linker.c) for
   PPC 64-bit is not implemented. The system runtime
   (dynamic) linker works.
 * The handling of the system stack (register 1) is not ELF-
   compliant so stack traces break. Instead of allocating a new
   stack frame, spill code should use the "official" spill area
   in the current stack frame and deallocation code should restore
   the back chain
 * DWARF support is missing

 Fixes #9863

 Test Plan: validate (on powerpc, too)

 Reviewers: simonmar, trofi, erikd, austin

 Reviewed By: trofi

 Subscribers: bgamari, arnons1, kgardas, thomie

 Differential Revision: https://phabricator.haskell.org/D629

 GHC Trac Issues: #9863
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9863#comment:7>
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