[m-dev.] Bug 321
jfischer at opturion.com
Sat Feb 22 14:59:36 AEDT 2014
On Sat, 22 Feb 2014, Paul Bone wrote:
> On Fri, Feb 21, 2014 at 11:24:02PM +1100, Julien Fischer wrote:
>> On Fri, 21 Feb 2014, Paul Bone wrote:
>>> I'm tracking down bug 321. https://www.mercurylang.org/bugs/view.php?id=321
>>> As you recall this is the symptom:
>>> The C linker gives me errors such as:
>>> paul at oxygen> mmc --rebuild test -O2 --intermodule-optimization
>>> Making Mercury/int3s/test.int3
>>> Making Mercury/ints/test.int
>>> Making Mercury/opts/test.opt
>>> Making Mercury/cs/test.c
>>> Making Mercury/os/test.o
>>> Making test
>>> ** Error making `test'.
>>> Mercury/os/test.o: In function `<predicate 'test.try_divide'/3 mode
>>> test.c:(.text+0xe6): undefined reference to `<predicate
>>> 'exception.wrap_success_or_failure'/2 mode 0>'
>>> collect2: error: ld returned 1 exit status
>>> After looking at the exception.m code and the HLDS dumps during compilation
>>> of my test.m I found that:
>>> The linker can't find an address for: wrap_success_or_failure/2
>>> But it can find addresses for: get_determinism/2
>> Is your test.m the same as the file bug321.m that you uploaded to
>> Mantis? I ask, because when I try the file from Mantis everything
>> seems fine ...
> Yes it is except for the module name.
>>> Both predicates are called by the same code in the HLDS representation of
>>> test.m but one works and what doesn't.
>> ... and when I look at the HLDS dumps (of bug321.m)I see no reference to
> Are you using the same options as above and in the bug report -O2
Yes, in fact I tried everything from -O2 to -O6.
The major difference would be that I am looking at it on a system that
doesn't use ELF executables! (The problem doesn't seem to occur on
Mac OS X with either hlc.gc or none.gc at least).
I'll have a look on Linux later today - however, your bug report is a little
bit sketchy about the details of the system you were using:
* Linux (presumably)
* 32-bit or 64-bt?
* GCC version?
* Was the Mercury compiler installed directly from the srcdist or
was it recompiled in another grade?
* Which grade? The bug report says low-level C grade, does that mean
that you've checked all of none.gc, reg.gc and asm_fast.gc and the bug
occurs with all of them?
>>> So I looked at readelf(1) dump of libmer_std.so's symbol table.
>>> get_determinism/2 is exported globally and wrap_success_or_failure/2 is
>>> exported locally.
>>> Both are declared and defined in the implementation section of the exception
>>> module. So now I want to know why is one being treated differently.
>> get_determinism/2 is exported globally from exception.o because it
>> is referred to by opt-exported clauses in optimization interface for the
>> exception module. (It is also subject of a no_inline pragma so its own
>> clauses do not appear in the .opt file.)
>> wrap_success_or_failure/2 is not exported because it only refererred by
>> the predicate try_det, whose own clauses are not opt-exported.
> Okay that's odd. I'll look more closely.
What's odd? That try_det isn't opt-exported?
More information about the developers