telemetry: Improve perf profiler

tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper.py

Index: tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper.py
diff --git a/tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper.py b/tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper.py
index b746251b6b81c4b8b9c84f2ebd93607fa0d236b9..f2e21440385eb434bb870307841356d9be3dcbbc 100644
--- a/tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper.py
+++ b/tools/telemetry/telemetry/core/platform/profiler/android_profiling_helper.py
@@ -6,16 +6,27 @@ import glob
 import hashlib
 import logging
 import os
+import platform
 import re
 import shutil
 import subprocess
 
+from telemetry.core import util
 from telemetry.core.platform.profiler import android_prebuilt_profiler_helper
 
 
 _TEXT_SECTION = '.text'
 
 
+def _ElfMachineId(elf_file):
+  headers = subprocess.check_output(['readelf', '-h', elf_file])
+  return re.match(r'.*Machine:\s+(\w+)', headers, re.DOTALL).group(1)
+
+
+def _ElfSectionAsString(elf_file, section):
+  return subprocess.check_output(['readelf', '-p', section, elf_file])
+
+
 def _ElfSectionMd5Sum(elf_file, section):
   result = subprocess.check_output(
       'readelf -p%s "%s" | md5sum' % (section, elf_file), shell=True)
@@ -23,20 +34,27 @@ def _ElfSectionMd5Sum(elf_file, section):
 
 
 def _FindMatchingUnstrippedLibraryOnHost(device, lib):
-  out_path = os.path.join(os.environ.get('CHROMIUM_OUT_DIR', 'out'), 'Release')
   lib_base = os.path.basename(lib)
 
   device_md5 = device.old_interface.RunShellCommandWithSU('md5 "%s"' % lib)[0]
   device_md5 = device_md5.split(' ', 1)[0]
 
-  # First find a matching stripped library on the host. This avoids the need to
-  # pull the stripped library from the device, which can take tens of seconds.
-  host_lib_pattern = os.path.join(out_path, '*_apk', 'libs', '*', lib_base)
-  for stripped_host_lib in glob.glob(host_lib_pattern):
-    with open(stripped_host_lib) as f:
-      host_md5 = hashlib.md5(f.read()).hexdigest()
-      if host_md5 == device_md5:
-        break
+  def FindMatchingStrippedLibrary(out_path):
+    # First find a matching stripped library on the host. This avoids the need
+    # to pull the stripped library from the device, which can take tens of
+    # seconds.
+    host_lib_pattern = os.path.join(out_path, '*_apk', 'libs', '*', lib_base)
+    for stripped_host_lib in glob.glob(host_lib_pattern):
+      with open(stripped_host_lib) as f:
+        host_md5 = hashlib.md5(f.read()).hexdigest()
+        if host_md5 == device_md5:
+          return stripped_host_lib
+
+  for build_dir, build_type in util.GetBuildDirectories():
+    out_path = os.path.join(build_dir, build_type)
+    stripped_host_lib = FindMatchingStrippedLibrary(out_path)
+    if stripped_host_lib:
+      break
   else:
     return None
 
@@ -176,3 +194,41 @@ def PrepareDeviceForPerf(device):
   device.old_interface.SetProtectedFileContents(
       '/proc/sys/kernel/kptr_restrict', '0')
   return android_prebuilt_profiler_helper.GetDevicePath('perf')
+
+
+def GetToolchainBinaryPath(library_file, binary_name):
+  """Return the path to an Android toolchain binary on the host.
+
+  Args:
+    library_file: ELF library which is used to identify the used ABI,
+        architecture and toolchain.

[bulach, 2014/06/09 10:06:52]

hmm...
I suppose we require md5sum_device to be built, so maybe omit this param and
just do the readelf on os.path.join(constants.GetOutDirectory(),
md5sum_device_bin) ?

alternatively, could also inspect getprop ro.product.cpu.abi?

[Sami, 2014/06/09 11:39:01]

That's a great idea, but I think it has the same problem that made me decide not
to use ro.product.cpu.abi: the device can support multiple ABIs and its not
clear which one to return here. For instance on x86 devices ro.product.cpu.abi
is most likely ARM and ro.product.cpu.abi2 is x86.

Since you generally want to use a toolchain binary with something that came out
of the toolchain (i.e., an ELF file), I think it makes sense to make this
function dependent on that information.

By the way, I'm not if we need to build our own md5sum anymore since we have
/system/bin/md5. Probably not on ICS though:
https://android.googlesource.com/platform/system/core/+/d0455c952d61d36e662f4...

+    binary_name: Binary to search for, e.g., 'objdump'
+  Returns:
+    Full path to binary or None if the binary was not found.
+  """
+  # Mapping from ELF machine identifiers to GNU toolchain names.
+  toolchain_configs = {
+    'x86': 'i686-linux-android',
+    'MIPS': 'mipsel-linux-android',
+    'ARM': 'arm-linux-androideabi',
+    'x86-64': 'x86_64-linux-android',
+    'AArch64': 'aarch64-linux-android',
+  }
+  toolchain_config = toolchain_configs[_ElfMachineId(library_file)]
+  host_os = platform.uname()[0].lower()
+  host_machine = platform.uname()[4]
+
+  elf_comment = _ElfSectionAsString(library_file, '.comment')
+  toolchain_version = re.match(r'.*GCC: \(GNU\) ([\w.]+)',
+                               elf_comment, re.DOTALL)
+  if not toolchain_version:
+    return None
+  toolchain_version = toolchain_version.group(1)
+
+  path = os.path.join(util.GetChromiumSrcDir(), 'third_party', 'android_tools',
+                      'ndk', 'toolchains',
+                      '%s-%s' % (toolchain_config, toolchain_version),
+                      'prebuilt', '%s-%s' % (host_os, host_machine), 'bin',
+                      '%s-%s' % (toolchain_config, binary_name))
+  path = os.path.abspath(path)
+  return path if os.path.exists(path) else None