[lldb] [lit] Set LD_LIBRARY_PATH or alike for Suite tests

[mgorny]

Summary

Set LD_LIBRARY_PATH or local platform's equivalent of it when running
the 'Suite' tests. This is necessary when running tests inside build
tree with BUILD_SHARED_LIBS enabled, in order to make the LLDB modules
load freshly built LLVM libraries.

The code is copied from clang (test/Unit/lit.cfg). SHLIBDIR
substitution is added to site-config (already present in top-level LLDB
site-config) to future-proof this into supporting stand-alone builds
with shared LLDB libraries.

[labath]

Doesn't seem particularly elegant, but it seems clang is doing the same thing, so probably best to follow suit.

[mgorny]

While working on other patches, I've noticed top-level lit.site.cfg* has SHLIBDIR which serves the same purpose as in clang. I've updated this patch to include it for Suite tests, and therefore future-proof it for stand-alone builds with shared LLDB libraries. This is also what clang does, exactly.

I've also fixed indentation to match LLDB style.

[mgorny]

Thank you for the review. When I find some more time, I'll try to convert this into utility function somewhere in lit.

lldb/lit/Suite/lit.cfg

 # -*- Python -*-
 
 # Configuration file for the 'lit' test runner.
 
 import os
+import platform
 import shlex
 
 import lit.formats
 
 # name: The name of this test suite.
 config.name = 'lldb-Suite'
 
 # suffixes: A list of file extensions to treat as test files.
if 'Address' in config.llvm_use_sanitizer and \
   resource_dir = subprocess.check_output(
     config.cmake_cxx_compiler +' -print-resource-dir', shell=True).strip()
   runtime = os.path.join(resource_dir, 'lib', 'darwin',
                          'libclang_rt.asan_osx_dynamic.dylib')
   config.environment['ASAN_OPTIONS'] = \
     'detect_stack_use_after_return=1'
   config.environment['DYLD_INSERT_LIBRARIES'] = runtime
 
+# Shared library build of LLVM may require LD_LIBRARY_PATH or equivalent.
+def find_shlibpath_var():
+    if platform.system() in ['Linux', 'FreeBSD', 'NetBSD', 'SunOS']:
+        yield 'LD_LIBRARY_PATH'
+    elif platform.system() == 'Darwin':
+        yield 'DYLD_LIBRARY_PATH'
+    elif platform.system() == 'Windows':
+        yield 'PATH'
+
+for shlibpath_var in find_shlibpath_var():
+    shlibpath = os.path.pathsep.join(
+        (config.llvm_libs_dir,
+         config.environment.get(shlibpath_var, '')))
+    config.environment[shlibpath_var] = shlibpath
+    break
+else:
+    lit_config.warning("unable to inject shared library path on '{}'"
+                       .format(platform.system()))
+
 # Build dotest command.
 dotest_cmd = [config.dotest_path, '-q']
 dotest_cmd.extend(config.dotest_args_str.split(';'))
 
 # We don't want to force users passing arguments to lit to use `;` as a
 # separator. We use Python's simple lexical analyzer to turn the args into a
 # list.
 if config.dotest_lit_args_str:
   dotest_cmd.extend(shlex.split(config.dotest_lit_args_str))
 
 # Load LLDB test format.
 sys.path.append(os.path.join(config.lldb_src_root, "lit", "Suite"))
 import lldbtest
 
 # testFormat: The test format to use to interpret tests.
 config.test_format = lldbtest.LLDBTest(dotest_cmd)