Build libc++ with ndk-build instead of bash.

Before this patch we had to maintain two sets of build rules for
libc++: build-cxx-stl.sh and Android.mk. This changes the prebuild
step from using the shell script to just invoking ndk-build.

For one, this means that anyone using LIBCXX_FORCE_REBUILD will
actually get a reliable result, as it's the same way we built it.

It's also quite a bit faster. It now takes only 45 seconds to build
all 8 ABIs, whereas before this patch it took 3 minutes and 15
seconds. Aside from the cost of building everything, we also benefit
from dependency checking now since we store the intermediate files in
a reliable location, which means that a null build doesn't take long
(it still takes some time because we have to run the packaging step).

Now that this has been done for libc++, we could also do this for
stlport. It may not be worth the effort, however, since that's not
being actively worked on.

Note that this patch also drops the prebuilt ARM (non-thumb)
libraries. There wasn't actually any way to use them, so there's
nothing lost here.

Change-Id: I8602f0fd3a23a2938cdc5be19d0714d5567ce6fc

4 files changed, 60 insertions, 28 deletions

diff --git a/sources/cxx-stl/llvm-libc++/.gitignore b/sources/cxx-stl/llvm-libc++/.gitignore
index 8f45b0d54..28a55e51c 100644
--- a/sources/cxx-stl/llvm-libc++/.gitignore
+++ b/sources/cxx-stl/llvm-libc++/.gitignore
@@ -1,3 +1,2 @@
 libs/
-/repo.prop
 /libcxx/test/lit.site.cfg
diff --git a/sources/cxx-stl/llvm-libc++/Android.mk b/sources/cxx-stl/llvm-libc++/Android.mk
index a55b4d8da..ef46ee130 100644
--- a/sources/cxx-stl/llvm-libc++/Android.mk
+++ b/sources/cxx-stl/llvm-libc++/Android.mk
@@ -103,14 +103,6 @@ android_support_c_includes := $(LOCAL_PATH)/../../android/support/include
 include $(CLEAR_VARS)
 LOCAL_MODULE := c++_static
 LOCAL_SRC_FILES := libs/$(TARGET_ARCH_ABI)/lib$(LOCAL_MODULE)$(TARGET_LIB_EXTENSION)
-# For armeabi*, choose thumb mode unless LOCAL_ARM_MODE := arm
-ifneq (,$(filter armeabi%,$(TARGET_ARCH_ABI)))
-ifneq (arm,$(LOCAL_ARM_MODE))
-ifneq (arm,$(TARGET_ARM_MODE))
-LOCAL_SRC_FILES := libs/$(TARGET_ARCH_ABI)/thumb/lib$(LOCAL_MODULE)$(TARGET_LIB_EXTENSION)
-endif
-endif
-endif
 LOCAL_EXPORT_C_INCLUDES := $(llvm_libc++_export_includes) $(android_support_c_includes)
 LOCAL_EXPORT_CPPFLAGS := $(llvm_libc++_export_cxxflags)
 include $(PREBUILT_STATIC_LIBRARY)
@@ -118,14 +110,6 @@ include $(PREBUILT_STATIC_LIBRARY)
 include $(CLEAR_VARS)
 LOCAL_MODULE := c++_shared
 LOCAL_SRC_FILES := libs/$(TARGET_ARCH_ABI)/lib$(LOCAL_MODULE)$(TARGET_SONAME_EXTENSION)
-# For armeabi*, choose thumb mode unless LOCAL_ARM_MODE := arm
-ifneq (,$(filter armeabi%,$(TARGET_ARCH_ABI)))
-ifneq (arm,$(LOCAL_ARM_MODE))
-ifneq (arm,$(TARGET_ARM_MODE))
-LOCAL_SRC_FILES := libs/$(TARGET_ARCH_ABI)/thumb/lib$(LOCAL_MODULE)$(TARGET_SONAME_EXTENSION)
-endif
-endif
-endif
 LOCAL_EXPORT_C_INCLUDES := $(llvm_libc++_export_includes) $(android_support_c_includes)
 LOCAL_EXPORT_CPPFLAGS := $(llvm_libc++_export_cxxflags)
 include $(PREBUILT_SHARED_LIBRARY)
diff --git a/sources/cxx-stl/llvm-libc++/Application.mk b/sources/cxx-stl/llvm-libc++/Application.mk
new file mode 100644
index 000000000..eada7edd8
--- /dev/null
+++ b/sources/cxx-stl/llvm-libc++/Application.mk
@@ -0,0 +1,4 @@
+NDK_TOOLCHAIN_VERSION := clang
+# Even the system STL is too much because it will link libsupc++ for rtti and
+# exceptions.
+APP_STL := none
diff --git a/sources/cxx-stl/llvm-libc++/build.py b/sources/cxx-stl/llvm-libc++/build.py
index df26bba18..270dfb5bc 100755
--- a/sources/cxx-stl/llvm-libc++/build.py
+++ b/sources/cxx-stl/llvm-libc++/build.py
@@ -18,15 +18,18 @@
 from __future__ import print_function
 
 import os
+import shutil
 import site
+import subprocess
 
-site.addsitedir(os.path.join(os.path.dirname(__file__), '../../../build/lib'))
+THIS_DIR = os.path.realpath(os.path.dirname(__file__))
+site.addsitedir(os.path.join(THIS_DIR, '../../../build/lib'))
 
-import build_support
+import build_support  # pylint: disable=import-error
 
 
 class ArgParser(build_support.ArgParser):
-    def __init__(self):
+    def __init__(self):  # pylint: disable=super-on-old-class
         super(ArgParser, self).__init__()
 
         self.add_argument(
@@ -43,18 +46,60 @@ def main(args):
     for arch in arches:
         abis.extend(build_support.arch_to_abis(arch))
 
-    print('Building libc++ for ABIs: {}'.format(' '.join(abis)))
+    ndk_build = build_support.ndk_path('build/ndk-build')
+    prebuilt_ndk = build_support.android_path('prebuilts/ndk/current')
+    platforms_root = os.path.join(prebuilt_ndk, 'platforms')
+    toolchains_root = os.path.join(prebuilt_ndk, 'toolchains')
+    libcxx_path = build_support.ndk_path('sources/cxx-stl/llvm-libc++')
+    obj_out = os.path.join(args.out_dir, 'libcxx/obj')
+
+    # TODO(danalbert): Stop building to the source directory.
+    # This is historical, and simplifies packaging a bit. We need to pack up
+    # all the source as well as the libraries. If build_support.make_package
+    # were to change to allow a list of directories instead of one directory,
+    # we could make this unnecessary.  Will be a follow up CL.
+    lib_out = os.path.join(libcxx_path, 'libs')
 
-    abis_arg = '--abis={}'.format(','.join(abis))
-    ndk_dir_arg = '--ndk-dir={}'.format(build_support.ndk_path())
-    script = build_support.ndk_path('build/tools/build-cxx-stl.sh')
     build_cmd = [
-        'bash', script, '--stl=libc++-libc++abi', abis_arg, ndk_dir_arg,
-        build_support.jobs_arg(), build_support.toolchain_path(),
-        '--with-debug-info', '--llvm-version=3.6',
+        'bash', ndk_build, '-C', THIS_DIR, build_support.jobs_arg(), 'V=1',
+        'APP_ABI=' + ' '.join(abis),
+
+        # Use the prebuilt platforms and toolchains.
+        'NDK_PLATFORMS_ROOT=' + platforms_root,
+        'NDK_TOOLCHAINS_ROOT=' + toolchains_root,
+        'NDK_NEW_TOOLCHAINS_LAYOUT=true',
+
+        # Tell ndk-build where all of our makefiles are and where outputs
+        # should go. The defaults in ndk-build are only valid if we have a
+        # typical ndk-build layout with a jni/{Android,Application}.mk.
+        'NDK_PROJECT_PATH=null',
+        'APP_BUILD_SCRIPT=' + os.path.join(THIS_DIR, 'Android.mk'),
+        'NDK_APPLICATION_MK=' + os.path.join(THIS_DIR, 'Application.mk'),
+        'NDK_OUT=' + obj_out,
+        'NDK_LIBS_OUT=' + lib_out,
+
+        # Make sure we don't pick up a cached copy.
+        'LIBCXX_FORCE_REBUILD=true',
+
+        # Put armeabi-v7a-hard in its own directory.
+        '_NDK_TESTING_ALL_=yes',
     ]
+    print('Building libc++ for ABIs: {}'.format(', '.join(abis)))
+    subprocess.check_call(build_cmd)
+
+    # The static libraries are installed to NDK_OUT, not NDK_LIB_OUT, so we
+    # need to install them to our package directory.
+    for abi in abis:
+        static_lib_dir = os.path.join(obj_out, 'local', abi)
+        install_dir = os.path.join(lib_out, abi)
+
+        shutil.copy2(os.path.join(static_lib_dir, 'libc++_static.a'),
+                     install_dir)
+        shutil.copy2(os.path.join(static_lib_dir, 'libandroid_support.a'),
+                     install_dir)
+
+    build_support.make_package('libcxx', libcxx_path, args.dist_dir)
 
-    build_support.build(build_cmd, args)
 
 if __name__ == '__main__':
     build_support.run(main, ArgParser)