[lit] Disable test on darwin when building shared libs.

[hintonda]

Summary

This test fails to link shared libraries because tries to run
a copied version of clang-check to see if the mock version of libcxx
in the same directory can be loaded dynamically. Since the test is
specifically designed not to look in the default just-built lib
directory, it must be disabled when building with
BUILD_SHARED_LIBS=ON.

Currently only disabling it on Darwin and basing it on the
enable_shared flag.

[hintonda]

@zturner, I only disabled this on Darwin because that's all I can test on right now. Please let me know if there's a better way to do this or if it should fire on different platforms.

[hintonda]

ping...

[hintonda]

ping...

[sammccall]

Sorry, I don't have any context on this (I just "blindly" fixed an asan error at one point).

Adding original authors/reviewers of the test.

[ilya-biryukov]

LGTM, I see no way around it, we can't copy all of the shared libs.
Maybe there's an alternative way to test this without copying the binary, but I don't have one in mind.

[phosek]

This broke all our macOS builders:

llvm-lit: /b/s/w/ir/k/llvm-project/llvm/utils/lit/lit/TestingConfig.py:102: fatal: unable to parse config file '/b/s/w/ir/k/recipe_cleanup/clangh7IvHV/llvm_build_dir/tools/lld/test/lit.site.cfg.py', traceback: Traceback (most recent call last):
  File "/b/s/w/ir/k/llvm-project/llvm/utils/lit/lit/TestingConfig.py", line 89, in load_from_path
    exec(compile(data, path, 'exec'), cfg_globals, None)
  File "/b/s/w/ir/k/recipe_cleanup/clangh7IvHV/llvm_build_dir/tools/lld/test/lit.site.cfg.py", line 31, in <module>
    lit.llvm.initialize(lit_config, config)
  File "/b/s/w/ir/k/llvm-project/llvm/utils/lit/lit/llvm/__init__.py", line 9, in initialize
    llvm_config = config.LLVMConfig(lit_config, test_config)
  File "/b/s/w/ir/k/llvm-project/llvm/utils/lit/lit/llvm/config.py", line 51, in __init__
    if config.enable_shared:
AttributeError: TestingConfig instance has no attribute 'enable_shared'

The problem is that enable_shared isn't defined in lld's lit.site.cfg.py. Is it possible to either fix this or revert this change?

[thakis]

I reverted this in r363379 to unbreak check-lld on mac. I think the

if config.enable_shared:
               features.add("enable_shared")

bit belongs in clang/test/lit.cfg.py, not in llvm/utils/lit/lit/llvm/config.py.

[hintonda]

In D61697#1543443, @thakis wrote:

I reverted this in r363379 to unbreak check-lld on mac. I think the

if config.enable_shared:
               features.add("enable_shared")

bit belongs in clang/test/lit.cfg.py, not in llvm/utils/lit/lit/llvm/config.py.

Sorry the breakage, and thanks for the suggestion.

Fixed in r363502.

clang/test/Tooling/clang-check-mac-libcxx-fixed-compilation-db.cpp

 // RUN: cp clang-check %t/mock-libcxx/bin/
 // RUN: cp %s %t/test.cpp
 // RUN: "%t/mock-libcxx/bin/clang-check" -p %t %t/test.cpp -- \
 // RUN:     -stdlib=libc++ -target x86_64-apple-darwin \
 // RUN:     -ccc-install-dir %t/mock-libcxx/bin
 //
 // ^ -ccc-install-dir passed to unbreak tests on *BSD where
 //   getMainExecutable() relies on real argv[0] being passed
+//
+// UNSUPPORTED: enable_shared
 #include <mock_vector>
 vector v;

llvm/utils/lit/lit/llvm/config.py

def __init__(self, lit_config, config):
             features.add('shell')
 
         # Running on Darwin OS
         if platform.system() == 'Darwin':
             # FIXME: lld uses the first, other projects use the second.
             # We should standardize on the former.
             features.add('system-linker-mach-o')
             features.add('system-darwin')
+            if config.enable_shared:
+                features.add("enable_shared")
         elif platform.system() == 'Windows':
             # For tests that require Windows to run.
             features.add('system-windows')
         elif platform.system() == "Linux":
             features.add('system-linux')
         elif platform.system() in ['FreeBSD']:
             config.available_features.add('system-freebsd')
         elif platform.system() == "NetBSD":