[libc] Extend libc's linux script to handle runtimes build.

[sivachandra]

Summary

lntue, michaelrj

[gkistanova]

LGTM.

zorg/buildbot/builders/annotated/libc-linux.py

 #!/usr/bin/python
 
 import argparse
 import os
 import subprocess
 import sys
 import traceback
 import util
 from contextlib import contextmanager
 
 
 def is_fullbuild_builder(builder_name):
     return ('fullbuild' in builder_name.split('-'))
 
+def is_runtimes_builder(builder_name):
+    return ('runtimes' in builder_name.split('-'))
+
 
 def main(argv):
     ap = argparse.ArgumentParser()
     ap.add_argument('--asan', action='store_true', default=False,
                     help='Build with address sanitizer enabled.')
     ap.add_argument('--debug', action='store_true', default=False,
                     help='Build in debug mode.')
     args, _ = ap.parse_known_args()
 
     source_dir = os.path.join('..', 'llvm-project')
-    fullbuild = is_fullbuild_builder(os.environ.get('BUILDBOT_BUILDERNAME'))
+    builder_name = os.environ.get('BUILDBOT_BUILDERNAME')
+    fullbuild = is_fullbuild_builder(builder_name)
+    runtimes_build = is_runtimes_builder(builder_name)
 
     with step('cmake', halt_on_fail=True):
-        projects = ['llvm', 'libc', 'clang', 'clang-tools-extra']
-
         # On most systems the default generator is make and the default
         # compilers are gcc and g++. We make it explicit here that we want
         # clang and ninja which reduces one step of setting environment
         # variables when setting up workers.
         cmake_args = ['-GNinja',
                       '-DCMAKE_C_COMPILER=clang',
                       '-DCMAKE_CXX_COMPILER=clang++']
+
+        if runtimes_build:
+          projects = ['llvm', 'clang']
+          cmake_args.append('-DLLVM_ENABLE_RUNTIMES=libc')
+        else:
+          projects = ['llvm', 'libc']
+
         if args.debug:
             cmake_args.append('-DCMAKE_BUILD_TYPE=Debug')
         else:
             cmake_args.append('-DCMAKE_BUILD_TYPE=Release')
 
         if args.asan:
             cmake_args.append('-DLLVM_USE_SANITIZER=Address')
 
with step('cmake', halt_on_fail=True):
             cmake_args.extend(['-DLLVM_LIBC_FULL_BUILD=ON']),
 
         run_command(['cmake', os.path.join(source_dir, 'llvm')] + cmake_args)
 
     with step('build llvmlibc', halt_on_fail=True):
         run_command(['ninja', 'llvmlibc'])
 
     with step('check-libc'):
+        if runtimes_build:
+          run_command(['ninja', 'check-llvmlibc'])
+        else:
           run_command(['ninja', 'check-libc'])
 
     if fullbuild and not args.asan:
         with step('libc-integration-tests'):
             run_command(['ninja', 'libc-integration-tests'])
         with step('libc-api-test'):
             run_command(['ninja', 'libc-api-test'])
         with step('libc-fuzzer'):
             run_command(['ninja', 'libc-fuzzer'])