DMD test suite not runnable on Debian/Linux

[H. S. Teoh via Digitalmars-d]

On Fri, Jun 09, 2017 at 10:34:00PM +0000, Seb via Digitalmars-d wrote:
> On Friday, 9 June 2017 at 22:14:30 UTC, H. S. Teoh wrote:
> > I'm trying to track down an autotester failure in a DMD PR, and
> > getting very frustrated that the DMD test suite does not run on
> > Debian/Linux because of the whole PIE-by-default fiasco that
> > necessitates compiling everything with -fPIC.
> > 
> > (1) Currently, there is no way to customize how test/Makefile
> > compiles d_do_tests.d, so there is no way to insert -fPIC into the
> > offending compile line.
> 
> Once this PR is merged, it will at least use the default conf file:
> 
> https://github.com/dlang/dmd/pull/6870
> 
> (the config file is now in generated and this lead to nice errors on
> my machine)

But you see, that's the problem. What happens if the auto-generated
config file needs further adjustment?


> > (2) d_do_tests itself runs compile commands with `-conf=`, so
> > putting -fPIC inside dmd.conf has no effect (where otherwise it does
> > the right thing when dmd is invoked "normally"). There's no obvious
> > way to make customize the compile command used for each test: I
> > tried setting the environment variable ARGS but that just messed up
> > the test runner's expected outputs. Tried to add -fPIC to the DMD
> > environment variable but that blew up in a different way.
> 
> Do you mean DFLAGS with DMD environment variable?

There is no DFLAGS defined in d_do_tests.d.  The only configurable
parameter I can see is the DMD variable, so I tried to bluff d_do_tests
by setting DMD="dmd -fPIC", but that also didn't work, maybe because it
doesn't go through shell interpolation so it tries to find a
non-existent executable named "dmd -fPIC".

Anyway, I eventually went back to my trusty old anti-makefile
workaround: create a wrapper shell script that does this:

	#!/bin/sh
	/path/to/dmd -fPIC -I/path/to/druntime/import -I/path/to/phobos "$@"

(Yes, the -I's are necessary, I don't know why and don't really want to
at this point.)

Save this to /path/to/dmdwrapper, and then run make with
DMD=/path/to/dmdwrapper, and lo and behold, finally the miserable test
suite is runnable.

That was 2 hours' worth of frustration just to get the testsuite
running.  I dunno about you, but being unable to run the dmd testsuite
seems to me to be a big turnoff for potential dmd contributors. I
surmise not every potential dmd contributor is as persistent as I am.
:-D


> > So basically, I'm stuck up PIE creek without a paddle, and have no
> > way to locally test DMD changes without hogging more load on the
> > autotester.
> 
> Don't worry about that. It's just a computer. As a temporary
> workaround, docker might be worth considering.

Wow.  Way to bring out the shotgun to kill an ant!  I think installing
docker would be total overkill for something that really ought to work
out-of-the-box...!


> > Why is something so simple so hard to do?!
> 
> I think it's simply because not many people use the DMD test suite and
> those who do are used to the pain or have their custom-built tricks.
> Also I guess that there are two groups of people:
> 
> A) wow that's complicated and frustrating -> move on to the next great
> thing in life B) eh what the heck. I have seen worse...
> 
> (And not many in-between).

Ha, so now I've invented my own custom-built trick to make it work, and
so that's no help to the next would-be dmd contributor that comes along
and can't figure out how to make it work. :-/

//

On a tangential note, now that I finally got the miserable test suite
running, I've managed to figure out that the problem in my dmd PR was
caused by src/ddmd/globals.h not being auto-generated from
src/ddmd/globals.d, so when I added new fields to the Global struct, the
C++ code that use globals.h with the old definition crashed. I suppose
this is just a relic from the pre-self-hosting days, but it would be
nice if these last .h files were gotten rid of in the near future.

That, or we should (ab)use the .di generation facility or some sed
script to generate these .h files, so that they won't go out-of-sync
inadvertently.


T

-- 
LINUX = Lousy Interface for Nefarious Unix Xenophobes.