ci: Start running wasm32 tests on Travis

[alexcrichton]

This commit allocates a builder to running wasm32 tests on Travis. Not all test
suites pass right now so this is starting out with just the run-pass and the
libcore test suites. This'll hopefully give us a pretty broad set of coverage
for integration in rustc itself as well as a somewhat broad coverage of the llvm
backend itself through integration/unit tests.

[alexcrichton]

This is the successor of #45905 and #46291 and will help ensure that we don't regress features in wasm over time. Notably this will ensure we don't regress rustc integration itself, the ability to create wasm executables/dylibs/etc, as well as functionality in libstd/libcore. This also relatively importantly actually puts the llvm backend to the test to ensure its correctness.

In testing this turned up a bug previously known about in LLVM but one I hadn't gotten around to fixing yet. I've now backported the fix to our LLVM fork as well as the LLVM 5 branch and it's included here to help the tests pass.

Note that some downsides of this include:

• Yet another target which may require liberal // ignore annotations to new tests. The wasm target ignores everything that emscripten would ignore so it's maybe not too bad, but there's certainly a lot of // ignore-wasm32-bare already.
• Debugging wasm failures is crazy hard. There's no debugger! There's no println! It's mostly a stare-and-pray game.

I think that despite these downsides though it's good to get ahead of the game and get this target testing sooner rather than later. I think these points will get better over time as more and more functionality is implemented (like debuggers or "real" imports).

[kennytm]

I think it's better to remove this line over opting-out in bootstrap/check.rs? There needs to be a FIXME comment next to one of the workarounds anyway.

[alexcrichton]

Sure yeah, I preemptively added that to get a ./x.py test --target wasm32-... working, but we can always easily add it back later.

[hanna-kruppe]

Would be good to link #46298 here

[alexcrichton]

👍

[alexcrichton]

Updated!

r? @kennytm

[kennytm]

@bors r+ p=20

(raising priority since new tests from other PRs may not pass)

[bors]

📌 Commit e6977bb has been approved by kennytm

[bors]

⌛ Testing commit e6977bb74a1a75bc2ba405c1519f6d39093ddcd8 with merge ee17cf124e93f32e8eb27bb3180dafbcba8db0c9...

[bors]

💔 Test failed - status-travis

[steveklabnik]

looks spurious?

�[0Ktravis_fold:end:after_failure.1
�[0Ktravis_fold:start:after_failure.2
�[0Ktravis_time:start:28f0a230
�[0K$ cat obj/tmp/sccache.log
WARN:sccache::cache::s3: Got AWS error: Error(BadHTTPStatus(NotFound), State { next_error: None })
WARN:sccache::cache::s3: Got AWS error: Error(BadHTTPStatus(NotFound), State { next_error: None })

travis_time:end:28f0a230:start=1511825893488996918,finish=1511825893494620866,duration=5623948
�[0Ktravis_fold:end:after_failure.2
�[0Ktravis_fold:start:after_failure.3
�[0Ktravis_time:start:093c2a7c
�[0K$ cat /tmp/sccache.log
cat: /tmp/sccache.log: No such file or directory

travis_time:end:093c2a7c:start=1511825893499958946,finish=1511825893504677327,duration=4718381
�[0Ktravis_fold:end:after_failure.3
�[0Ktravis_fold:start:after_failure.4
�[0Ktravis_time:start:024aa040
�[0K$ ls -lat $HOME/Library/Logs/DiagnosticReports/
ls: cannot access /home/travis/Library/Logs/DiagnosticReports/: No such file or directory

travis_time:end:024aa040:start=1511825893510452059,finish=1511825893516475163,duration=6023104
�[0Ktravis_fold:end:after_failure.4
�[0Ktravis_fold:start:after_failure.5
�[0Ktravis_time:start:04998e31
�[0K$ find $HOME/Library/Logs/DiagnosticReports -type f -not -name '*.stage2-*.crash' -not -name 'com.apple.CoreSimulator.CoreSimulatorService-*.crash' -exec printf travis_fold":start:crashlog\n\033[31;1m%s\033[0m\n" {} \; -exec head -750 {} \; -exec echo travis_fold":"end:crashlog \;
find: `/home/travis/Library/Logs/DiagnosticReports': No such file or directory

travis_time:end:04998e31:start=1511825893522040560,finish=1511825893528102089,duration=6061529
�[0Ktravis_fold:end:after_failure.5
�[0Ktravis_fold:start:after_failure.6
�[0Ktravis_time:start:1095a09c
�[0K$ dmesg | grep -i kill
[   17.681956] init: failsafe main process (1133) killed by TERM signal

travis_time:end:1095a09c:start=1511825893532877544,finish=1511825893540881585,duration=8004041
�[0Ktravis_fold:end:after_failure.6
�[0K

[kennytm]

No, legit.

[01:39:21] failures:
[01:39:21] 
[01:39:21] ---- [mir-opt] mir-opt/packed-struct-drop-aligned.rs stdout ----
[01:39:21] 	thread '[mir-opt] mir-opt/packed-struct-drop-aligned.rs' panicked at 'Did not find expected line, error: Mismatch in lines
[01:39:21] Currnt block:     bb0: {
[01:39:21] Expected Line: "        drop(_6) -> bb2;                 // scope 1 at /checkout/src/test/mir-opt/packed-struct-drop-aligned.rs:13:5: 13:8"
[01:39:21] Actual Line: "        drop(_6) -> [return: bb4, unwind: bb3];"

[alexcrichton]

nah I think that's a test I need to ignore, I'll do that in a bit

[alexcrichton]

@bors: r=kennytm

[bors]

📌 Commit 73970bf has been approved by kennytm

[bors]

⌛ Testing commit 73970bf with merge 71340ca...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: kennytm
Pushing 71340ca to master...

[steveklabnik]

Not only am I pumped that this landed, but @alexcrichton , apparently this is the 2000th PR you've closed out! 🎊 💯 ❤️