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Tripe test failure update

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I am currently running the following procedure to find out at which
point the triple test of my SubC compiler fails. This is what happens:

The stage-0 (third-party-compiled) scc0 is used to generate a stage-1
scc1. Then scc1 is used to generate the stage-2 compiler scc2.

Then scc1 compiles itself to 1) assembly 2) a binary. The same is done
with scc2.

The assembly output of scc1 and scc2 is identical, the binaries are not.
*Both* compilers seem to work perfectly fine.

The assembler and linker of the Linux system are used to generate
binaries from the assembly output.

Adding a stage-3 compiler (compiled with scc2) and comparing against
scc2 does not change anything: same assembly, different executables.

The test as described above works (identical binaries) on FreeBSD/386,
FreeBSD/x86-64, FreeBSD/ARM, NetBSD-x86-64, DOS-8086, and others.

It sometimes fails (maybe depending on version?) on Linux-x86-64.
(OpenBSD/386 was a false negative.)

Differences in the file are literally all over the place. A diff on
the hexdumps reports multiple thousand differences).

All differences I have found so far are related to addresses, like in
the following disassembly snippet:

SCC
00000353 74 02                          jz      0x00000357
00000355 EB 16                          ljmp    0x0000036D
00000357 E8 AD F6 00 00                 lcall   0x0000FA09   *****
0000035C 48                             dec     %eax
0000035D 89 04 25 38 96 61 00           movl    %eax, 0x619638(,1)
------------------------------------------------------------------
SCC1
00000353 74 02                          jz      0x00000357
00000355 EB 16                          ljmp    0x0000036D
00000357 E8 47 F6 00 00                 lcall   0x0000F9A3   *****
0000035C 48                             dec     %eax
0000035D 89 04 25 38 96 61 00           movl    %eax, 0x619638(,1)

I would say that the cause for the difference is in the assembler
or linker, but I would like to understand what is going on here.

John wrote:
[Are the stage-0 and stage-1 assembly sources the same?  The
first thing that occurs to me is that the code is laid out
differently so the variable-length branch logic has long
and short instructions in different places. -John]

Yes, the stages 0 and 1 generate identical assembly output,
so any change in the layout would have to happen in later
phases (i.e. assembly and linking). How can that happen?

--
Nils M Holm  < n m h @ t 3 x . o r g >  www.t3x.org
[When you compared the individual object files that the assembler
genereated, what did you find? -John]

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Thread

Mysterious triple test failures "Nils M Holm" <nmh@t3x.org> - 2014-05-03 21:38 +0200
  Re: Mysterious triple test failures Kaz Kylheku <kaz@kylheku.com> - 2014-05-03 22:19 +0000
    Tripe test failure update "Nils M Holm" <nmh@t3x.org> - 2014-05-04 10:53 +0200
      Re: Triple test failure update Chris Dodd <cdodd@acm.org> - 2014-05-23 01:50 +0000
        Re: Triple test failure update "Nils M Holm" <nmh@t3x.org> - 2014-05-23 09:09 +0200
        Re: Triple test failure update alexfrunews@gmail.com - 2014-05-23 02:17 -0700
  Re: Mysterious triple test failures mrs@Kithrup.COM (Mike Stump) - 2014-05-04 04:47 +0000
  Re: Mysterious triple test failures alexfrunews@gmail.com - 2014-05-04 03:57 -0700
    Re: Tripe test failure update "Nils M Holm" <nmh@t3x.org> - 2014-05-05 10:30 +0200

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