3.2 PATCH: Support O32 ABI on IRIX 6

[Rainer Orth]

Daniel Jacobowitz writes:

> Do all three have explicit ABI flags in the ELF header?  I don't know
> how SGI handles that.  Otherwise, please don't remove the
> .mdebug.<ABI>. sections....

Here's what readelf -h gives for O32, N32, and N64 object files:

O32:

ELF Header:
  Magic:   7f 45 4c 46 01 02 01 00 00 00 00 00 00 00 00 00 
  Class:                             ELF32
  Data:                              2's complement, big endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              REL (Relocatable file)
  Machine:                           MIPS R3000
  Version:                           0x1
  Entry point address:               0x0
  Start of program headers:          0 (bytes into file)
  Start of section headers:          1180 (bytes into file)
  Flags:                             0x10000003, noreorder, pic, mips2
  Size of this header:               52 (bytes)
  Size of program headers:           0 (bytes)
  Number of program headers:         0
  Size of section headers:           40 (bytes)
  Number of section headers:         10
  Section header string table index: 2

N32:

ELF Header:
  Magic:   7f 45 4c 46 01 02 01 00 00 00 00 00 00 00 00 00 
  Class:                             ELF32
  Data:                              2's complement, big endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              REL (Relocatable file)
  Machine:                           MIPS R3000
  Version:                           0x1
  Entry point address:               0x0
  Start of program headers:          0 (bytes into file)
  Start of section headers:          2016 (bytes into file)
  Flags:                             0x30000022, pic, abi2, mips4
  Size of this header:               52 (bytes)
  Size of program headers:           0 (bytes)
  Number of program headers:         0
  Size of section headers:           40 (bytes)
  Number of section headers:         24
  Section header string table index: 2

N64:

ELF Header:
  Magic:   7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 
  Class:                             ELF64
  Data:                              2's complement, big endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              REL (Relocatable file)
  Machine:                           MIPS R3000
  Version:                           0x1
  Entry point address:               0x0
  Start of program headers:          0 (bytes into file)
  Start of section headers:          2360 (bytes into file)
  Flags:                             0x30000012, pic, ugen_reserved, mips4
  Size of this header:               64 (bytes)
  Size of program headers:           0 (bytes)
  Number of program headers:         0
  Size of section headers:           64 (bytes)
  Number of section headers:         23
  Section header string table index: 2

So the distinction is easy:

O32 vs. N32:

--- hello.o.readelf-h.o32       Wed Jun 19 15:30:26 2002
+++ hello.o.readelf-h.n32       Wed Jun 19 15:30:51 2002

-  Flags:                             0x10000003, noreorder, pic, mips2
+  Flags:                             0x30000022, pic, abi2, mips4

I.e. N32 adds EF_MIPS_ABI2.

N32 vs. N64 (apart from ELFCLASS32 vs. ELFCLASS64):

--- hello.o.readelf-h.n32       Wed Jun 19 15:30:51 2002
+++ hello.o.readelf-h.n64       Wed Jun 19 15:31:20 2002

-  Flags:                             0x30000022, pic, abi2, mips4
+  Flags:                             0x30000012, pic, ugen_reserved, mips4

This is just misprinted by current binutils: 0x10 is EF_IRIX_ABI64 now, as
can be seen in IRIX 6 <sys/elf.h>.

	Rainer