[libunwind] Fix linker flag handling in the tests.

[danielkiss]

Summary

--export-dynamic is not always available on all targets.
-funwind-tables was a duplicate in the lit.site.cfg.in.

[danielkiss]

self.cxx has a function to test compiler flags addFlagIfSupported but there is no support for linker flag (yet).

[arichardson]

libunwind/test/libunwind/test/config.py

47

This also works on most other operating systems that use ld.lld/ld.bfd (e.g. FreeBSD). Maybe it should be 'darwin' not in self.config.target_triple?

[danielkiss]

libunwind/test/libunwind/test/config.py

47

Make sense to me, hopefully we have enough bots to tests all.

libunwind/test/libunwind/test/config.py

def configure_features(self):
         if self.get_lit_bool('arm_ehabi', False):
             self.config.available_features.add('libunwind-arm-ehabi')
 
     def configure_compile_flags(self):
         self.cxx.compile_flags += ['-DLIBUNWIND_NO_TIMER']
         # Stack unwinding tests need unwinding tables and these are not
         # generated by default on all Targets.
         self.cxx.compile_flags += ['-funwind-tables']
+        # Make symbols available in the tests.
+        if 'linux' in self.config.target_triple:
+            self.cxx.link_flags += ['-Wl,--export-dynamic']
         if not self.get_lit_bool('enable_threads', True):
             self.cxx.compile_flags += ['-D_LIBUNWIND_HAS_NO_THREADS']
             self.config.available_features.add('libunwind-no-threads')
         super(Configuration, self).configure_compile_flags()
 
     def configure_compile_flags_header_includes(self):
         self.configure_config_site_header()
 

libunwind/test/lit.site.cfg.in

 config.suffixes = ['.cpp', '.s']
 
 # test_source_root: The root path where tests are located.
 config.test_source_root = os.path.join(config.libunwind_src_root, 'test')
 
 # Allow expanding substitutions that are based on other substitutions
 config.recursiveExpansionLimit = 10
 
-# Make symbols available in the tests.
-config.test_compiler_flags += " -funwind-tables "
-config.test_linker_flags += " -Wl,--export-dynamic "
-
 # Infer the test_exec_root from the build directory.
 config.test_exec_root = os.path.join(config.libunwind_obj_root, 'test')
 
 import libcxx.test.format
 config.test_format = libcxx.test.format.CxxStandardLibraryTest()
 
 lit_config.note('Using configuration variant: libunwind')
 import libunwind.test.config
 configuration = libunwind.test.config.Configuration(lit_config, config)
 configuration.configure()
 configuration.print_config_info()