Android: Make stack.py work with secondary ABI on Clang

When Chromium changed to use Clang, the secondary ABI output directory
changed names.  Support that name, but also, return to using library
size as a means of matching up libraries.  This didn't work prior to
using lld, but does work now.  Preserve the original matching system as
a fallback.

Bug: 986622
Change-Id: Ia469eed5b0b69d8a4fe2840526ba817df362099d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1955821
Commit-Queue: Christopher Grant <cjgrant@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#723062}

third_party/android_platform/development/scripts/stack_core.py

@@ -29,7 +29,6 @@ import zipfile
 
 import symbol
 
-
 from pylib import constants
 
 UNKNOWN = '<unknown>'
@@ -518,11 +517,12 @@ def GetUncompressedSharedLibraryFromAPK(apkname, offset):
   return soname, sosize
 
 
-def _GetSharedLibraryInHost(soname, dirs):
+def _GetSharedLibraryInHost(soname, sosize, dirs):
   """Find a shared library by name in a list of directories.
 
   Args:
     soname: library name (e.g. libfoo.so)
+    sosize: library file size to match.
     dirs: list of directories to look for the corresponding file.
   Returns:
     host library path if found, or None
@@ -531,6 +531,8 @@ def _GetSharedLibraryInHost(soname, dirs):
     host_so_file = os.path.join(dir, os.path.basename(soname))
     if not os.path.isfile(host_so_file):
       continue
+    if os.path.getsize(host_so_file) != sosize:
+      continue
     logging.debug("%s match to the one in APK" % host_so_file)
     return host_so_file
 
@@ -587,17 +589,12 @@ def _FindSharedLibraryFromAPKs(output_directory, apks_directory, offset):
     soname, sosize = GetUncompressedSharedLibraryFromAPK(apk, offset)
     if soname == "":
       continue
-    # The relocation section of libraries in APK is packed, we can't
-    # detect library by its size, and have to rely on the order of lib
-    # directories; for a specific ARCH, the libraries are in either
-    # output_directory or output_directory/android_ARCH, and android_ARCH
-    # directory could exists or not, so having android_ARCH directory be in
-    # first, we will find the correct lib.
-    dirs = [
-        os.path.join(output_directory, "android_%s" % symbol.ARCH),
-        output_directory,
+    dirs = [output_directory] + [
+        os.path.join(output_directory, x)
+        for x in os.listdir(output_directory)
+        if os.path.exists(os.path.join(output_directory, x, 'lib.unstripped'))
     ]
-    host_so_file = _GetSharedLibraryInHost(soname, dirs)
+    host_so_file = _GetSharedLibraryInHost(soname, sosize, dirs)
     if host_so_file:
       shared_libraries += [(soname, host_so_file)]
   # If there are more than one libraries found, it means detecting

third_party/android_platform/development/scripts/stack_test.py

@@ -70,22 +70,36 @@ class FakeSymbolizer:
       return [('??', '??:0:0')]
 
     namespace = basename.split('.')[0].replace('lib', '', 1)
+
+    # Determine if the lib is a secondary ABI library, in which case, preface
+    # its namespace with '32'.
+    if 'android_clang_' in file:
+      namespace += '32'
+
     method_name = '{}::Func_{:X}'.format(namespace, address)
     return [(method_name, '{}.cc:1:1'.format(namespace))]
 
 
 class StackDecodeTest(unittest.TestCase):
-
   def setUp(self):
+    self._num_libraries = 0
     self._temp_dir = tempfile.mkdtemp()
 
   def tearDown(self):
     shutil.rmtree(self._temp_dir)
 
   def _MakeElf(self, file):
+    # Make the unstripped lib directory in case stack.py looks for it.
+    dir = os.path.join(os.path.dirname(file), 'lib.unstripped')
+    if not os.path.exists(dir):
+      os.makedirs(dir)
+
     # Create a library slightly less than 4K in size, so that when added to an
-    # APK archive, all libraries end up on 4K boundaries.
-    data = '\x7fELF' + ' ' * 0xE00
+    # APK archive, all libraries end up on 4K boundaries. Also, make each
+    # library a slightly different size, since stack.py may utilize size when
+    # matching up libraries.
+    data = '\x7fELF' + ' ' * (0xE00 - self._num_libraries)
+    self._num_libraries += 1
     with open(file, 'wb') as f:
       f.write(data)
 
@@ -229,6 +243,41 @@ class StackDecodeTest(unittest.TestCase):
       ''')
     self._RunCase(input, expected, apks)
 
+  def test_MultiArchPrimaryAbi(self):
+    apks = {
+        'monochrome.apk': [
+            'libmonochrome.so', 'android_clang_arm/libmonochrome.so'
+        ],
+    }
+    # With both architectures present, verify that the correct ABI output and
+    # directory is chosen, even if identically-named libraries exist in both.
+    input = textwrap.dedent('''
+      DEBUG : #01 pc 00000174  /path==/base.apk (offset 0x00001000)
+      ''')
+    expected = textwrap.dedent('''
+      00000174   monochrome::Func_174         monochrome.cc:1:1
+      ''')
+    self._RunCase(input, expected, apks)
+
+  def test_MultiArchSecondary(self):
+    apks = {
+        'monochrome.apk': [
+            'libmonochrome.so', 'android_clang_arm/libmonochrome.so'
+        ],
+    }
+    # With both architectures present, verify that the secondary ABI output
+    # directory is chosen when appropriate, even if identically-named libraries
+    # exist in both. This must be a different test from the primary ABI case,
+    # since in practice, traces are from a single ABI (and the script relies on
+    # this).
+    input = textwrap.dedent('''
+      DEBUG : #02 pc 00000274  /path==/base.apk (offset 0x00002000)
+      ''')
+    expected = textwrap.dedent('''
+      00000274   monochrome32::Func_274       monochrome32.cc:1:1
+      ''')
+    self._RunCase(input, expected, apks)
+
 
 if __name__ == '__main__':
   unittest.main()