[LibFuzzer] Split the fuzzer-oom.test into two tests.

[delcypher]

Summary

[LibFuzzer] Split the fuzzer-oom.test into two tests.

This is necessary because the existing fuzzer-oom.test was Linux
specific due to its use of __sanitizer_print_memory_profile() which
is only available on Linux right now and so the test would fail on OSX.

The two tests are selectively disable by adding a new feature (linux
or darwin) which is set based on the host platform.

[kcc]

Interesting solution!
But wrong. :(
Essentially, you are now not testing that the heap profile is printed, but that libFuzzer successfully bypasses the test.
Instead of this, I suggest to make two copies of test/fuzzer-oom.test.
One will remain as is and require linux.
Another one will work on darwing too, but will not check for "Live Heap Allocations:"

[delcypher]

In D20977#448818, @kcc wrote:

Interesting solution!
But wrong. :(

I had a feeling you'd say that. This patch does feel like a massive hack.

Essentially, you are now not testing that the heap profile is printed, but that libFuzzer successfully bypasses the test.
Instead of this, I suggest to make two copies of test/fuzzer-oom.test.
One will remain as is and require linux.
Another one will work on darwing too, but will not check for "Live Heap Allocations:"

That's essentially what I mentioned in the patch summary (`In the future if we want to better test information about the live
heap allocations..`) as something we should do so I'm happy to make the change you suggest.

[delcypher]

Rework patch. Maybe I should use XFAIL rather than REQUIRES here?

[kcc]

lib/Fuzzer/test/fuzzer-oom-darwin.test

1 ↗

(On Diff #59804)

Why does this require darwin?

[delcypher]

lib/Fuzzer/test/fuzzer-oom-darwin.test

1 ↗

(On Diff #59804)

Technically it doesn't but my assumption is this would be the test for darwin (e.g. OSX). Do you want me to remove the REQUIRES: darwin line and remove darwin from the name of the test?

[kcc]

lib/Fuzzer/test/fuzzer-oom-darwin.test

1 ↗

(On Diff #59804)

Yes, and yes.
And remove linux from the other test's name (call it e.g. "oom-wit-profile")

lib/Fuzzer/test/lit.cfg

31 ↗

(On Diff #59804)

And you will not need parts about darwin here

[delcypher]

• Renames tests
• Remove 'darwin' from feature list

[kcc]

LGTM

llvm/trunk/lib/Fuzzer/test/fuzzer-oom-with-profile.test

+REQUIRES: linux
+RUN: not LLVMFuzzer-OutOfMemoryTest -rss_limit_mb=10 2>&1 | FileCheck %s
+CHECK: ERROR: libFuzzer: out-of-memory (used: {{.*}}; limit: 10Mb)
+CHECK: Live Heap Allocations
+CHECK: Test unit written to ./oom-
+SUMMARY: libFuzzer: out-of-memory

llvm/trunk/lib/Fuzzer/test/fuzzer-oom.test

 RUN: not LLVMFuzzer-OutOfMemoryTest -rss_limit_mb=10 2>&1 | FileCheck %s
 CHECK: ERROR: libFuzzer: out-of-memory (used: {{.*}}; limit: 10Mb)
-CHECK: Live Heap Allocations
 CHECK: Test unit written to ./oom-
 SUMMARY: libFuzzer: out-of-memory

llvm/trunk/lib/Fuzzer/test/lit.cfg

 import lit.formats
+import sys
 
 config.name = "LLVMFuzzer"
 config.test_format = lit.formats.ShTest(True)
 config.suffixes = ['.test']
 config.test_source_root = os.path.dirname(__file__)
 
 # Tweak PATH to include llvm tools dir and current exec dir.
 llvm_tools_dir = getattr(config, 'llvm_tools_dir', None)
else:
   lit_config.note('dfsan feature unavailable')
 
 if config.has_lsan:
   lit_config.note('lsan feature available')
   config.available_features.add('lsan')
 else:
   lit_config.note('lsan feature unavailable')
 
+if sys.platform.startswith('linux'):
+  # Note the value of ``sys.platform`` is not consistent
+  # between python 2 and 3, hence the use of ``.startswith()``.
+  lit_config.note('linux feature available')
+  config.available_features.add('linux')
+else:
+  lit_config.note('linux feature unavailable')