| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
This extends the previous work to revive the unregisterised GHC build
for AIX/ppc32. Strictly speaking, AIX runs on POWER4 (and later)
hardware, but the PPC32 instructions implemented in the PPC NCG
represent a compatible subset of the POWER4 ISA.
IBM AIX follows the PowerOpen ABI (and shares many similiarites with the
Linux PPC64 ELF V1 NCG backend) but uses the rather limited XCOFF
format (compared to ELF).
This doesn't support dynamic libraries yet.
A major limiting factor is that the AIX assembler does not support the
`@ha`/`@l` relocation types nor the ha16()/lo16() functions Darwin's
assembler supports. Therefore we need to avoid emitting those. In case
of numeric literals we simply compute the functions ourselves, while for
labels we have to use local TOCs and hope everything fits into a 16bit
offset (for ppc32 this gives us at most 16384 entries per TOC section,
which is enough to compile GHC).
Another issue is that XCOFF doesn't seem to have a relocation type for
label-differences, and therefore the label-differences placed into
tables-next-to-code can't be relocated, but the linker may rearrange
different sections, so we need to place all read-only sections into the
same `.text[PR]` section to workaround this.
Finally, the PowerOpen ABI distinguishes between function-descriptors
and actualy entry-point addresses. For AIX we need to be specific when
emitting assembler code whether we want the address of the function
descriptor `printf`) or for the entry-point (`.printf`). So we let the
asm pretty-printer prefix a dot to all emitted subroutine
calls (i.e. `BL`) on AIX only. For now, STG routines' entry-point labels
are not prefixed by a label and don't have any associated
function-descriptor.
Reviewers: austin, trommler, erikd, bgamari
Reviewed By: trommler, erikd, bgamari
Differential Revision: https://phabricator.haskell.org/D2019
|
|
|
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
|
