Add more functionality to glibc symbol checker.

Also scan NDK's unwanted symbols list (to show the things that we're
exporting but the NDK isn't. Symbols hidden in the NDK will be marked
with a *.

Add a -u (--unwanted) flag to disable the first two printed groups
(all symbols in bionic, all symbols in glibc). This is helpful when
wanting to grep in the list of unwanted symbols.

Finally, update the list of known differences between us and glibc.

Change-Id: I6fdb4126823098430454763c391bd8cd369a75bb

libc/tools/check-symbols-glibc.py

@@ -3,12 +3,18 @@
 import glob
 import os
 import re
-import string
 import subprocess
 import sys
 
+only_unwanted = False
+if len(sys.argv) > 1:
+  if sys.argv[1] in ('-u', '--unwanted'):
+    only_unwanted = True
+
 toolchain = os.environ['ANDROID_TOOLCHAIN']
 arch = re.sub(r'.*/linux-x86/([^/]+)/.*', r'\1', toolchain)
+if arch == 'aarch64':
+  arch = 'arm64'
 
 def GetSymbolsFromSo(so_file):
   # Example readelf output:
@@ -50,6 +56,15 @@ def MangleGlibcNameToBionic(name):
     return glibc_to_bionic_names[name]
   return name
 
+def GetNdkIgnored():
+  global arch
+  symbols = set()
+  files = glob.glob('%s/ndk/build/tools/unwanted-symbols/%s/*' %
+                    (os.getenv('ANDROID_BUILD_TOP'), arch))
+  for f in files:
+    symbols |= set(open(f, 'r').read().splitlines())
+  return symbols
+
 glibc_to_bionic_names = {
   '__res_init': 'res_init',
   '__res_mkquery': 'res_mkquery',
@@ -59,6 +74,7 @@ glibc_to_bionic_names = {
 
 glibc = GetSymbolsFromSystemSo('libc.so.*', 'librt.so.*', 'libpthread.so.*', 'libresolv.so.*', 'libm.so.*')
 bionic = GetSymbolsFromAndroidSo('libc.so', 'libm.so')
+ndk_ignored = GetNdkIgnored()
 
 glibc = map(MangleGlibcNameToBionic, glibc)
 
@@ -100,6 +116,16 @@ macro_stuff = set([
   '__errno',
   '__fe_dfl_env',
   '__get_h_errno',
+  '__fpclassifyd',
+  '__isfinite',
+  '__isfinitef',
+  '__isfinitel',
+  '__isnormal',
+  '__isnormalf',
+  '__isnormall',
+  '__sF',
+  '__pthread_cleanup_pop',
+  '__pthread_cleanup_push',
 ])
 # bionic exposes various Linux features that glibc doesn't.
 linux_stuff = set([
@@ -133,21 +159,62 @@ weird_stuff = set([
   'mknodat',
   'stat',
   'stat64',
+  'optreset',
+  'sigsetjmp',
+])
+# These exist in glibc, but under slightly different names (generally one extra
+# or one fewer _). TODO: check against glibc names.
+libresolv_stuff = set([
+  '__res_send_setqhook',
+  '__res_send_setrhook',
+  '_resolv_flush_cache_for_net',
+  '_resolv_set_nameservers_for_net',
+  'dn_expand',
+  'nsdispatch',
+])
+# libstdc++ stuff we took over.
+libstdcxx_stuff = set([
+  # new, delete, nothrow
+  '_ZSt7nothrow',
+  '_ZdaPv',
+  '_ZdaPvRKSt9nothrow_t',
+  '_ZdlPv',
+  '_ZdlPvRKSt9nothrow_t',
+  '_Znam',
+  '_ZnamRKSt9nothrow_t',
+  '_Znwm',
+  '_ZnwmRKSt9nothrow_t',
+
+  '__cxa_guard_abort',
+  '__cxa_guard_acquire',
+  '__cxa_guard_release',
+  '__cxa_pure_virtual',
+])
+# Implementation details we know we export (and can't get away from).
+known = set([
+  '_ctype_',
+  '__libc_init',
 ])
 
-print 'glibc:'
-for symbol in sorted(glibc):
-  print symbol
+if not only_unwanted:
+  print 'glibc:'
+  for symbol in sorted(glibc):
+    print symbol
 
-print
-print 'bionic:'
-for symbol in sorted(bionic):
-  print symbol
+  print
+  print 'bionic:'
+  for symbol in sorted(bionic):
+    print symbol
 
-print
-print 'in bionic but not glibc:'
-allowed_stuff = (bsd_stuff | FORTIFY_stuff | linux_stuff | macro_stuff | std_stuff | weird_stuff)
+  print
+  print 'in bionic but not glibc:'
+
+allowed_stuff = (bsd_stuff | FORTIFY_stuff | linux_stuff | macro_stuff |
+                 std_stuff | weird_stuff | libresolv_stuff | libstdcxx_stuff |
+                 known)
 for symbol in sorted((bionic - allowed_stuff).difference(glibc)):
+  if symbol in ndk_ignored:
+    symbol += '*'
   print symbol
 
 sys.exit(0)