[libc++] NFC: Simplify substitutions by using lit recursive substitutions

Since lit supports expanding substitutions recursively, we can define
substitutions in terms of other substitutions. This allows us to simplify
how libc++ substitutions are defined.

This doesn't change the substitutions at all, it only makes them simpler
to define.

Author: ldionne

libcxx/test/lit.cfg

@@ -53,3 +53,5 @@ configuration = config_module.Configuration(lit_config, config)
 configuration.configure()
 configuration.print_config_info()
 config.test_format = configuration.get_test_format()
+
+lit_config.recursiveExpansionLimit = 10

libcxx/utils/libcxx/test/config.py

@@ -1039,35 +1039,26 @@ def configure_substitutions(self):
         if self.target_info.is_darwin():
             # Do not pass DYLD_LIBRARY_PATH to the compiler, linker, etc. as
             # these tools are not meant to exercise the just-built libraries.
-            tool_env += 'env DYLD_LIBRARY_PATH="" '
+            tool_env += 'env DYLD_LIBRARY_PATH=""'
 
         sub = self.config.substitutions
-        cxx_path = tool_env + pipes.quote(self.cxx.path)
         # Configure compiler substitutions
-        sub.append(('%{cxx}', cxx_path))
+        sub.append(('%{cxx}', '{} {}'.format(tool_env, pipes.quote(self.cxx.path))))
         sub.append(('%{libcxx_src_root}', self.libcxx_src_root))
         # Configure flags substitutions
-        flags_str = ' '.join([pipes.quote(f) for f in self.cxx.flags])
-        compile_flags_str = ' '.join([pipes.quote(f) for f in self.cxx.compile_flags])
-        link_flags_str = ' '.join([pipes.quote(f) for f in self.cxx.link_flags])
-        all_flags = '%s %s %s' % (flags_str, compile_flags_str, link_flags_str)
-        sub.append(('%{flags}', flags_str))
-        sub.append(('%{compile_flags}', compile_flags_str))
-        sub.append(('%{link_flags}', link_flags_str))
+        sub.append(('%{flags}',         ' '.join(map(pipes.quote, self.cxx.flags))))
+        sub.append(('%{compile_flags}', ' '.join(map(pipes.quote, self.cxx.compile_flags))))
+        sub.append(('%{link_flags}',    ' '.join(map(pipes.quote, self.cxx.link_flags))))
         if self.cxx.isVerifySupported():
-            verify_str = ' ' + ' '.join(self.cxx.verify_flags) + ' '
-            sub.append(('%{verify}', verify_str))
-        # Add compile and link shortcuts
-        compile_str = (cxx_path + ' -o %t.o %s -c ' + flags_str
-                       + ' ' + compile_flags_str)
-        build_str = cxx_path + ' -o %t.exe %s ' + all_flags
+            sub.append(('%{verify}', ' '.join(self.cxx.verify_flags)))
+        # Add compile and build shortcuts
+        sub.append(('%{compile}', '%{cxx} -o %t.o %s -c %{flags} %{compile_flags}'))
+        sub.append(('%{build}',   '%{cxx} -o %t.exe %s %{flags} %{compile_flags} %{link_flags}'))
         if self.cxx.use_modules:
-            sub.append(('%{build_module}', build_str))
+            sub.append(('%{build_module}', '%{build}'))
         elif self.cxx.modules_flags is not None:
-            modules_str = ' '.join(self.cxx.modules_flags) + ' '
-            sub.append(('%{build_module}', build_str + ' ' + modules_str))
-        sub.append(('%{compile}', compile_str))
-        sub.append(('%{build}', build_str))
+            sub.append(('%{build_module}', '%{{build}} {}'.format(' '.join(self.cxx.modules_flags))))
+
         # Configure exec prefix substitutions.
         # Configure run env substitution.
         codesign_ident = self.get_lit_conf('llvm_codesign_identity', '')
@@ -1077,13 +1068,11 @@ def configure_substitutions(self):
                   '--dependencies %%file_dependencies --env %s -- ' %  \
             (pipes.quote(sys.executable), pipes.quote(run_py),
              codesign_ident, env_vars)
-        run_str = exec_str + '%t.exe'
         sub.append(('%{exec}', exec_str))
-        sub.append(('%{run}', run_str))
+        sub.append(('%{run}', '%{exec} %t.exe'))
         # Configure not program substitutions
         not_py = os.path.join(self.libcxx_src_root, 'utils', 'not.py')
-        not_str = '%s %s ' % (pipes.quote(sys.executable), pipes.quote(not_py))
-        sub.append(('%{not} ', not_str))
+        sub.append(('%{not}', '{} {}'.format(pipes.quote(sys.executable), pipes.quote(not_py))))
         if self.get_lit_conf('libcxx_gdb'):
             sub.append(('%{libcxx_gdb}', self.get_lit_conf('libcxx_gdb')))
 

libcxx/utils/libcxx/test/format.py

@@ -124,7 +124,8 @@ def _execute(self, test, lit_config):
         substitutions = lit.TestRunner.getDefaultSubstitutions(test, tmpDir,
                                                                tmpBase)
         substitutions.append(('%file_dependencies', ' '.join(data_files)))
-        script = lit.TestRunner.applySubstitutions(script, substitutions)
+        script = lit.TestRunner.applySubstitutions(script, substitutions,
+                                                   recursion_limit=lit_config.recursiveExpansionLimit)
 
         test_cxx = copy.deepcopy(self.cxx)
         if is_fail_test: