[compiler-rt][ubsan][test] XFAIL TypeCheck/misaligned.cpp on Sparc

[ro]

Summary

Two ubsan tests FAIL on Sparc:

UBSan-Standalone-sparc :: TestCases/TypeCheck/misaligned.cpp
UBSan-Standalone-sparcv9 :: TestCases/TypeCheck/misaligned.cpp

I've reported the details in Bug 47015, but it seems to boil down to the fact that the
s1 subtest actually incurs a fault on strict-alignment targets like Sparc which UBSan
doesn't expect.

I've found no way to XFAIL just that single subtest, so this patch XFAILs the whole
testcase.

Tested on sparcv9-sun-solaris2.11 and amd64-pc-solaris2.11.

[vsk]

As an alternative, would it be workable to convert this test to use -fsanitize-trap? That way, the test program would trap after issuing a runtime error (it can be run with not --crash %run ...).

[ro]

Use -fsanitize-trap for the s1 subtest.

[ro]

In D85433#2201003, @vsk wrote:

As an alternative, would it be workable to convert this test to use -fsanitize-trap? That way, the test program would trap after issuing a runtime error (it can be run with not --crash %run ...).

Yes, that works: by trapping directly at the point of the UB, there's no longer a difference between targets that actually fault and others that don't. I've kept the CHECK-STORE check in place since it's actually nicer/more detailed than just a SIGILL. Once ubsan can handle this case, the original check can be restored.

Again tested on sparcv9-sun-solaris2.11, amd64-pc-solaris2.11, and x86_64-pc-linux-gnu.

[vsk]

compiler-rt/test/ubsan/TestCases/TypeCheck/misaligned.cpp

12

Is it possible to write this as not --crash %run %t s1 2>&1 | FileCheck %s --check-prefix=CHECK-STORE? I'd expect the ubsan runtime to be able to print out the diagnostic, then call abort().

[ro]

compiler-rt/test/ubsan/TestCases/TypeCheck/misaligned.cpp

12

Unfortunately not: with -fsanitize-trap the runtime isn't entered at all. Everywhere I tried (Linux/x86_84, Solaris/sparcv9, Linux/sparc64) the test program just prints

Illegal Instruction (core dumped)

IIUC this is just the use case for -fsanitize-trap: environments where the runtime isn't available (kernel) or cannot be used (libc).

[vsk]

compiler-rt/test/ubsan/TestCases/TypeCheck/misaligned.cpp

12

I apologize - I mixed up -fsanitize-trap and -fno-sanitize-recover=alignment. According to https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html#usage, it should be possible to use the latter to enter the runtime and then abort.

[ro]

compiler-rt/test/ubsan/TestCases/TypeCheck/misaligned.cpp

12

You're right: quick manual testing suggests that this works fine.
I'll post the updated patch after proper testing later.

Thanks a lot: this is way better than just XFAILing the test.

[ro]

Use -fno-sanitize-recover=alignment for s1 subtest.

[ro]

compiler-rt/test/ubsan/TestCases/TypeCheck/misaligned.cpp

12

Full testing on sparcv9-sun-solaris2.11, amd64-pc-linux-gnu, and x86_64-pc-linux-gnu confirmed that this works just fine.

[vsk]

Thanks!

compiler-rt/test/ubsan/TestCases/TypeCheck/misaligned.cpp

 // RUN: %clangxx %gmlt -fsanitize=alignment %s -O3 -o %t
 // RUN: %run %t l0 && %run %t s0 && %run %t r0 && %run %t m0 && %run %t f0 && %run %t n0 && %run %t u0
 // RUN: %run %t l1 2>&1 | FileCheck %s --check-prefix=CHECK-LOAD --strict-whitespace
-// RUN: %run %t s1 2>&1 | FileCheck %s --check-prefix=CHECK-STORE
 // RUN: %run %t r1 2>&1 | FileCheck %s --check-prefix=CHECK-REFERENCE
 // RUN: %run %t m1 2>&1 | FileCheck %s --check-prefix=CHECK-MEMBER
 // RUN: %run %t f1 2>&1 | FileCheck %s --check-prefix=CHECK-MEMFUN
 // RUN: %run %t n1 2>&1 | FileCheck %s --check-prefix=CHECK-NEW
 // RUN: %run %t u1 2>&1 | FileCheck %s --check-prefix=CHECK-UPCAST
 // RUN: %env_ubsan_opts=print_stacktrace=1 %run %t l1 2>&1 | FileCheck %s --check-prefix=CHECK-LOAD --check-prefix=CHECK-STACK-LOAD
 
 // RUN: %clangxx -fsanitize=alignment -fno-sanitize-recover=alignment %s -O3 -o %t
+// RUN: not %run %t s1 2>&1 | FileCheck %s --check-prefix=CHECK-STORE
 // RUN: not %run %t w1 2>&1 | FileCheck %s --check-prefix=CHECK-WILD
 // Compilation error make the test fails.
 // XFAIL: openbsd
 
 #include <new>
 
 struct S {
   S() {}