Add simple VM test for precompiled code.

Add simple VM test for precompiled code.

The test creates a precompiled snapshot in a temporary directory, runs it and
checks the output.

Also:
Minor cleanup and fix segfault on dlopen error and with --trace-isolates

BUG=
R=rmacnak@google.com

Committed: https://github.com/dart-lang/sdk/commit/3a75f0d67a0170b12417033d9b64fc6b078a9b8b

[Florian Schneider, 2015-09-23 11:06:45]

fschneider@google.com changed reviewers:
+ rmacnak@google.com

[Bill Hesse, 2015-09-23 17:17:36]

whesse@google.com changed reviewers:
+ whesse@google.com

[Bill Hesse, 2015-09-23 17:17:37]

https://codereview.chromium.org/1362743003/diff/1/tests/standalone/precompila...
File tests/standalone/precompilation_test.dart (right):

https://codereview.chromium.org/1362743003/diff/1/tests/standalone/precompila...
tests/standalone/precompilation_test.dart:31: }
Maybe try and run gcc --version, and if it fails, don't fail the test.

[rmacnak, 2015-09-23 17:34:59]

lgtm

https://codereview.chromium.org/1362743003/diff/1/tests/standalone/precompila...
File tests/standalone/precompilation_test.dart (right):

https://codereview.chromium.org/1362743003/diff/1/tests/standalone/precompila...
tests/standalone/precompilation_test.dart:33: "gcc",
The ARM bots download a cross-compiled build instead of building itself, so they
might not have gcc installed.

https://codereview.chromium.org/1362743003/diff/1/tests/standalone/precompila...
tests/standalone/precompilation_test.dart:34: ["-shared", "-o",
"libprecompiled.so", "precompiled.S"],
If enabled for the simulators, should explicitly pass -m32 or -m64.

https://codereview.chromium.org/1362743003/diff/1/tests/standalone/standalone...
File tests/standalone/standalone.status (right):

https://codereview.chromium.org/1362743003/diff/1/tests/standalone/standalone...
tests/standalone/standalone.status:109: precompilation_test: Skip # Not expected
to run on ia32 and simulators.
It should work on the simulators.

[Florian Schneider, 2015-09-23 18:30:49]

https://codereview.chromium.org/1362743003/diff/1/tests/standalone/standalone...
File tests/standalone/standalone.status (right):

https://codereview.chromium.org/1362743003/diff/1/tests/standalone/standalone...
tests/standalone/standalone.status:109: precompilation_test: Skip # Not expected
to run on ia32 and simulators.
On 2015/09/23 17:34:59, rmacnak wrote:
> It should work on the simulators.

Did you run it sucessfully? Strange, it did not work for me: dlopen() fails.

[rmacnak, 2015-09-23 19:15:43]

On 2015/09/23 18:30:49, Florian Schneider wrote:
>
https://codereview.chromium.org/1362743003/diff/1/tests/standalone/standalone...
> File tests/standalone/standalone.status (right):
> 
>
https://codereview.chromium.org/1362743003/diff/1/tests/standalone/standalone...
> tests/standalone/standalone.status:109: precompilation_test: Skip # Not
expected
> to run on ia32 and simulators.
> On 2015/09/23 17:34:59, rmacnak wrote:
> > It should work on the simulators.
> 
> Did you run it sucessfully? Strange, it did not work for me: dlopen() fails.

You need to assemble the shared library with -m32 for simarm and simmips.
Otherwise it defaults to host machine's -m64 and you're trying to load an x64
shared library into an ia32 vm.

[rmacnak, 2015-09-23 19:17:26]

On 2015/09/23 19:15:43, rmacnak wrote:
> On 2015/09/23 18:30:49, Florian Schneider wrote:
> >
>
https://codereview.chromium.org/1362743003/diff/1/tests/standalone/standalone...
> > File tests/standalone/standalone.status (right):
> > 
> >
>
https://codereview.chromium.org/1362743003/diff/1/tests/standalone/standalone...
> > tests/standalone/standalone.status:109: precompilation_test: Skip # Not
> expected
> > to run on ia32 and simulators.
> > On 2015/09/23 17:34:59, rmacnak wrote:
> > > It should work on the simulators.
> > 
> > Did you run it sucessfully? Strange, it did not work for me: dlopen() fails.
> 
> You need to assemble the shared library with -m32 for simarm and simmips.
> Otherwise it defaults to host machine's -m64 and you're trying to load an x64
> shared library into an ia32 vm.

At least a shared library that claims to be x64, even if it is full of arm/mips
instructions.

[Florian Schneider, 2015-09-24 08:48:17]

On 2015/09/23 19:17:26, rmacnak wrote:
> On 2015/09/23 19:15:43, rmacnak wrote:
> > On 2015/09/23 18:30:49, Florian Schneider wrote:
> > >
> >
>
https://codereview.chromium.org/1362743003/diff/1/tests/standalone/standalone...
> > > File tests/standalone/standalone.status (right):
> > > 
> > >
> >
>
https://codereview.chromium.org/1362743003/diff/1/tests/standalone/standalone...
> > > tests/standalone/standalone.status:109: precompilation_test: Skip # Not
> > expected
> > > to run on ia32 and simulators.
> > > On 2015/09/23 17:34:59, rmacnak wrote:
> > > > It should work on the simulators.
> > > 
> > > Did you run it sucessfully? Strange, it did not work for me: dlopen()
fails.
> > 
> > You need to assemble the shared library with -m32 for simarm and simmips.
> > Otherwise it defaults to host machine's -m64 and you're trying to load an
x64
> > shared library into an ia32 vm.
> 
> At least a shared library that claims to be x64, even if it is full of
arm/mips
> instructions.

Ok, I thought I did that. But maybe I just ran the wrong binary anyway...

[Florian Schneider, 2015-09-24 09:36:36]

https://codereview.chromium.org/1362743003/diff/1/tests/standalone/precompila...
File tests/standalone/precompilation_test.dart (right):

https://codereview.chromium.org/1362743003/diff/1/tests/standalone/precompila...
tests/standalone/precompilation_test.dart:31: }
On 2015/09/23 17:17:37, Bill Hesse wrote:
> Maybe try and run gcc --version, and if it fails, don't fail the test.

Done.

https://codereview.chromium.org/1362743003/diff/1/tests/standalone/precompila...
tests/standalone/precompilation_test.dart:33: "gcc",
On 2015/09/23 17:34:59, rmacnak wrote:
> The ARM bots download a cross-compiled build instead of building itself, so
they
> might not have gcc installed.

Bill said they have gcc. But I'll add the check like suggested.

https://codereview.chromium.org/1362743003/diff/1/tests/standalone/precompila...
tests/standalone/precompilation_test.dart:34: ["-shared", "-o",
"libprecompiled.so", "precompiled.S"],
On 2015/09/23 17:34:59, rmacnak wrote:
> If enabled for the simulators, should explicitly pass -m32 or -m64.

Done. I didn't find a generic way to check for 32- vs 64-bit. So I end up using
the 'file' tool - but the test is Linux-only anyway because of gcc.

[Florian Schneider, 2015-09-24 09:36:52]

Committed patchset #3 (id:40001) manually as
3a75f0d67a0170b12417033d9b64fc6b078a9b8b (presubmit successful).