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.
- 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 Trac #9863