xcode4 - How can we restore ppc/ppc64 as well as full 10.4/10.5 SDK support to Xcode 4? - Stack Overflow

[Jeremy Huddleston]

On Mar 22, 2011, at 06:34, Christopher Stone wrote:

> Hey Folks,
> 
> I haven't tried this but thought it worth passing along.
> 
> http://stackoverflow.com/questions/5333490/how-can-we-restore-ppc-ppc64-as-well-as-full-10-4-10-5-sdk-support-to-xcode-4/5348547


Two thinks there look particularly scary to me.  One is the assumption that the old gcc 4.0 xcplugin from XCode3 will "just work" with XCode4. The other is replacing the new assembler with the old one.  I'm not familiar with the xcplugin API to know if the first issue is something that we (MacPorts) can really do anything about, but I know that the second is.  The assembler (as) is part of the cctools package in XCode.

XCode 3.2.6 has cctools-795 http://opensource.apple.com/tarballs/cctools/cctools-795.tar.gz
XCode 4.0.0 has cctools-800 http://opensource.apple.com/tarballs/cctools/cctools-800.tar.gz

The release notes* from 800 detail some changes between the two versions which you should probably be aware of if you decide to just replace it.  Many of these changes pertain to ARM support, so I would certainly not follow the advise on that website if you want to do iOS development.

Of course for those interested in going down this road, it might be better just to build the newer as with ppc support in MacPorts.  I haven't tried this myself, but it should be fairly straightforward as it doesn't look like ppc support was removed at the source-level based on diffing the two projects and the list of changes in the release notes:

Changes for the 5.29 release (the cctools-800 release):
- Fixed the arm VCVT (between half-precision and single-precision) instructions
  encodings.  Had the op bit inverted in the table.  It should have been:
    VCVT<c><q>.F32.F16 <Qd>, <Dm> Encoded as op = 1 (aka fcvtshp)
    VCVT<c><q>.F16.F32 <Dd>, <Qm> Encoded as op = 0 (aka fcvthps)
  Radar bug #8951023.
- Added the .incbin directive.  Radar bug #8945167.
- Changed the Makefile to install the ppc and ppc64 assembler in LOCLIBDIR.
  Radar bug #8828970.

Changes for the 5.28 release (the cctools-799 release):
- Found another path that -g was not checking to produce dwarf line table
  entries only for the text section.  That was in dwarf2_emit_insn() in
  dwarf2dbg.c.  Radar bug #8792738.
- Fixed the mishanding of the thumb2 tst instruction.  Changed do_t_mvn_tst()
  in arm.c.  Normally, the versions of the instructions that set condition flags
  aren't allowed inside IT blocks, so it's checking that.  TST<c>, however, is
  allowed and isn't accounted for.  Radar bug #8783763.
- Changed the arm assembler for ADD/SUB (immediate, Thumb) to correctly follow
  the manual's note about these instructions:
    encoding T1 is to be preferred if Rd is specified, and T2 is preferred if
    it is not.
  To do this do_t_add_sub() sets the unused 0x0100 in inst.instruction when
  using BFD_RELOC_ARM_THUMB_ADD to communicate to md_apply_fix() that two
  operands were present in assembly code.  Then md_apply_fix() uses this bit
  and checks the size of the immediate to see if the 3-bit immediate form can
  be uses as it should be preferred in that case.  Radar bug #8756030.

Changes for the 5.28 release (the cctools-798 release):
- Changed to error messages in arm.c which were:
    "invalid constant (%x) after fixup"
  to have 0x in front of the hex value.  Radar bug #8772178.
- Changed do_t_mul() in arm.c .  The problem is that the assembler didn't take
  into account that the "mul" mnemonic (w/o the 's' suffix) is valid for the
  16-bit wide encoding when in an IT block.  Radar bug #8755919.
- Added support for make aarm_test .
  - Added a arm-check.c that currently only does arm ALU instructions can set
    the condition codes.
  - Added #ifndef INSNS_TABLE_ONLY to arm.c so that can be #defined and included
    in arm-check.c .
  - Made the needed changes in the Makefile to add support for aarm_test .

Changes for the 5.28 release (the cctools-797 release):
- Changed the code that was adding the NULL DIE terminating the Compile Unit
  DIE's when producing dwarf debuging info for assembly files to not be
  conditional on if dwarf2_subprograms_info != NULL.  The change is at the end
  of out_debug_info() in dwarf2dbg.c . Radar bug #8441990 and #8443177.

Changes for the 5.28 release (the cctools-796 release):
- Changed the x86-64 assembler to allow immediate expressions of the form:
    movq $(xxx-L$y),%rax
  by changing output_imm() to look for 4 byte signed 32-bit expression and use
  the same trick in output_disp() to call fix_new() so it will use two
  relocation entries pointing at the same 32-bits.  Radar bug #7081262.
- Added the OpenSourceURL key to the cctools.plist file as:
    <key>OpenSourceURL</key>
    <string>
http://ftp.gnu.org/gnu/binutils/binutils-1.38.1.tar.gz
</string>
  Radar bug #8569655.

*: http://opensource.apple.com/source/cctools/cctools-800/as/notes