Windows: enable gold threading, copy libwinpthread-1.dllandroid-wear-p-preview-2android-p-preview-3android-p-preview-2android-o-mr1-iot-release-1.0.0android-o-mr1-iot-preview-8android-n-iot-release-lg-thinq-wk7o-mr1-iot-preview-8

Copy libwinpthread-1.dll alongside the binutils executables on Windows.

The install_winpthreads function is copied from llvm_android:
https://android.googlesource.com/toolchain/llvm_android/+/bd22d9779676661ae9571972dcd744c42c70ffd0/build.py#1063

Most C++ MinGW programs need libpthread, because even libstdc++'s
"operator new" pulls in EH code, which calls into libpthread. Currently,
the ld.gold.exe and dwp.exe binaries need libwinpthread-1.dll, which is
not generally in the PATH, so the binaries don't run.

Previously, the Android GCC build of binutils linked ld.gold.exe and
dwp.exe with -static, which selected the static libpthread.a. Packaging
libwinpthread-1.dll alongside the binaries ensures that ld.gold.exe and
the LLVMgold plugin use the same copy of the winpthreads runtime, which
might be important.

Test: ./toolchain/binutils/build.py --arch arm64 --host win64
Test: ./toolchain/binutils/build.py  --arch arm64 --host win
Test: ./toolchain/binutils/build.py --arch arm64  --host linux
Test: ./toolchain/binutils/build.py --arch x86 --host win64
Bug: none
Change-Id: I5fc2d38b67c72fa4760be1c2688ef88479759160

1 files changed, 30 insertions, 8 deletions

diff --git a/build.py b/build.py
index 4a4f0981..f22e8218 100755
--- a/build.py
+++ b/build.py
@@ -60,6 +60,12 @@ def chdir(path):
     os.chdir(path)
 
 
+def install_file(src, dst):
+    """shutil.copy2 with logging."""
+    logger().info('copy %s %s', src, dst)
+    shutil.copy2(src, dst)
+
+
 def check_call(cmd, *args, **kwargs):
     """subprocess.check_call with logging."""
     logger().info('check_call %s', subprocess.list2cmdline(cmd))
@@ -84,6 +90,7 @@ def configure(arch, host, install_dir, src_dir):
         '--host={}'.format(configure_host),
         '--enable-initfini-array',
         '--enable-plugins',
+        '--enable-threads',
         '--disable-nls',
         '--with-sysroot={}'.format(sysroot),
         '--prefix={}'.format(install_dir),
@@ -97,12 +104,6 @@ def configure(arch, host, install_dir, src_dir):
         # https://issuetracker.google.com/70838247
         configure_args.append('--enable-gold=default')
 
-    if not is_windows:
-        # Multithreaded linking is implemented with pthreads, which we
-        # historically couldn't use on Windows.
-        # TODO: Try enabling this now that we have winpthreads in mingw.
-        configure_args.append('--enable-threads')
-
     env = {}
 
     m32 = False
@@ -158,10 +159,31 @@ def build(jobs):
     check_call(['make', '-j', str(jobs)])
 
 
-def install(jobs):
+def install_winpthreads(is_windows32, install_dir):
+    """Installs the winpthreads runtime to the Windows bin directory."""
+    lib_name = 'libwinpthread-1.dll'
+    mingw_dir = ndk.paths.android_path(
+        'prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8',
+        'x86_64-w64-mingw32')
+    # Yes, this indeed may be found in bin/ because the executables are the
+    # 64-bit version by default.
+    pthread_dir = 'lib32' if is_windows32 else 'bin'
+    lib_path = os.path.join(mingw_dir, pthread_dir, lib_name)
+
+    lib_install = os.path.join(install_dir, 'bin', lib_name)
+    install_file(lib_path, lib_install)
+
+
+def install(jobs, arch, host, install_dir):
     """Installs binutils."""
     check_call(['make', 'install-strip', '-j', str(jobs)])
 
+    if host in ('win', 'win64'):
+        arch_install_dir = os.path.join(
+            install_dir, ndk.abis.arch_to_triple(arch))
+        install_winpthreads(host == 'win', install_dir)
+        install_winpthreads(host == 'win', arch_install_dir)
+
 
 def dist(dist_dir, base_dir, package_name):
     """Packages binutils for distribution."""
@@ -237,7 +259,7 @@ def main():
 
         install_timer = ndk.timer.Timer()
         with install_timer:
-            install(args.jobs)
+            install(args.jobs, args.arch, args.host, install_dir)
     finally:
         chdir(orig_dir)