User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:96.0) Gecko/20100101 Firefox/96.0

Steps to reproduce:

Running the tests on s390x leads to a failure

Actual results:

/<<PKGBUILDDIR>>/js/src/jit-test/tests/large-arraybuffers/basic.js:32:13 Error: Assertion failed: got -25089, expected -99            
Stack:                                                                                                                                
  test1@/<<PKGBUILDDIR>>/js/src/jit-test/tests/large-arraybuffers/basic.js:32:13                                                      
  @/<<PKGBUILDDIR>>/js/src/jit-test/tests/large-arraybuffers/basic.js:38:1                                                            
Exit code: 3                                                                                                                          
FAIL - large-arraybuffers/basic.js                                                                                                    
TEST-UNEXPECTED-FAIL | js/src/jit-test/tests/large-arraybuffers/basic.js | /<<PKGBUILDDIR>>/js/src/jit-test/tests/large-arraybuffers/b
asic.js:32:13 Error: Assertion failed: got -25089, expected -99 (code 3, args "") [0.0 s]                                             
INFO exit-status     : 3                                                                                                              
INFO timed-out       : False                                                                                                          
INFO stderr         2> /<<PKGBUILDDIR>>/js/src/jit-test/tests/large-arraybuffers/basic.js:32:13 Error: Assertion failed: got -25089, e
xpected -99                                                                                                                           
INFO stderr         2> Stack:                                                                                                         
INFO stderr         2> test1@/<<PKGBUILDDIR>>/js/src/jit-test/tests/large-arraybuffers/basic.js:32:13                                 
INFO stderr         2> @/<<PKGBUILDDIR>>/js/src/jit-test/tests/large-arraybuffers/basic.js:38:1

Expected results:

Test should have passed

The Bugbug bot thinks this bug should belong to the 'Core::JavaScript Engine: JIT' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

-99 == 0x9d
-25089 == 0x9dff

This looks like somebody loaded a signed byte and sign-extended it to 16 bits and then byte-swapped it (s390 is big-endian iirc), but other scenarios are possible.

Severity: S2 because this has a high impact for s390x users.
Priority: P5 as this is not a Tier 1 platform.

Contributions are welcome.

Do we have a simulator or anything to test big-endian platforms? I know we don't have any tier-1 big endian platforms, but it would be nice for something like this.

It would also be useful to check whether this fails when run with --jitflags=interp. If so, this should be moved to the JavaScript Engine component instead of the JIT.

(In reply to Steve Fink [:sfink] [:s:] from comment #4)

It would also be useful to check whether this fails when run with --jitflags=interp. If so, this should be moved to the JavaScript Engine component instead of the JIT.

We don't have a JIT backend for s390x, so this is definitely the interpreter.

After some discussion, we think this is more appropriately as S4 bug because this is just a test case failure.