# Copyright 2022 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import logging
import os
import re
import subprocess
_CHROME_SRC = os.path.join(os.path.dirname(__file__), os.pardir, os.pardir)
_LLVM_OBJDUMP_PATH = os.path.join(_CHROME_SRC, 'third_party', 'llvm-build',
'Release+Asserts', 'bin', 'llvm-objdump')
# Function lines look like:
# 000177b0 <android::IBinder::~IBinder()+0x2c>:
# We pull out the address and function first. Then we check for an optional
# offset. This is tricky due to functions that look like "operator+(..)+0x2c"
_FUNC = re.compile(r"(^[a-f0-9]*) <(.*)>:$")
_OFFSET = re.compile(r"(.*)\+0x([a-f0-9]*)")
# A disassembly line looks like:
# 177b2: b510 push {r4, lr}
_ASM = re.compile(r"(^[ a-f0-9]*):[ a-f0-0]*.*$")
def _StripPC(addr, cpu_arch):
"""Strips the Thumb bit from a program counter address when appropriate.
Args:
addr: the program counter address
cpu_arch: Target CPU architecture.
Returns:
The stripped program counter address.
"""
if cpu_arch == "arm":
return addr & ~1
return addr
class ObjdumpInformation(object):
def __init__(self, address, library, symbol, offset):
self.address = address
self.library = library
self.symbol = symbol
self.offset = offset
class LLVMObjdumper(object):
def __init__(self):
"""Creates an instance of LLVMObjdumper that interacts with llvm-objdump.
"""
self._llvm_objdump_parameters = [
'--disassemble',
'--demangle',
'--section=.text',
]
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
pass
@staticmethod
def GetSymbolDataFromObjdumpOutput(objdump_out, address, cpu_arch):
stripped_target_address = _StripPC(address, cpu_arch)
for line in objdump_out.split(os.linesep):
components = _FUNC.match(line)
if components:
# This is a new function, so record the current function and its
# address.
current_symbol_addr = int(components.group(1), 16)
current_symbol = components.group(2)
# Does it have an optional offset like: "foo(..)+0x2c"?
components = _OFFSET.match(current_symbol)
if components:
current_symbol = components.group(1)
offset = components.group(2)
if offset:
current_symbol_addr -= int(offset, 16)
# Is it a disassembly line like: "177b2: b510 push {r4, lr}"?
components = _ASM.match(line)
if components:
addr = components.group(1)
i_addr = int(addr, 16)
if i_addr == stripped_target_address:
return (current_symbol, stripped_target_address - current_symbol_addr)
return (None, None)
def GetSymbolInformation(self, lib, address, cpu_arch):
"""Returns the corresponding function names and line numbers.
Args:
lib: library to search for info.
address: address to look for info.
cpu_arch: architecture where the dump was taken
Returns:
An ObjdumpInformation object
"""
if not os.path.isfile(_LLVM_OBJDUMP_PATH):
logging.error('Cannot find llvm-objdump. path=%s', _LLVM_OBJDUMP_PATH)
return None
stripped_address = _StripPC(address, cpu_arch)
full_arguments = [_LLVM_OBJDUMP_PATH] + self._llvm_objdump_parameters
full_arguments.append('--start-address=' + str(stripped_address))
full_arguments.append('--stop-address=' + str(stripped_address + 8))
full_arguments.append(lib)
objdump_process = subprocess.Popen(full_arguments,
stdout=subprocess.PIPE,
stdin=subprocess.PIPE,
universal_newlines=True)
stdout, stderr = objdump_process.communicate()
objdump_process_return_code = objdump_process.poll()
if objdump_process_return_code != 0:
logging.error(
'Invocation of llvm-objdump failed!' +
' tool-command-line=\'{}\', return-code={}, std-error=\'{}\''.format(
' '.join(full_arguments), objdump_process_return_code, stderr))
return None
symbol, offset = LLVMObjdumper.GetSymbolDataFromObjdumpOutput(
stdout, address, cpu_arch)
return ObjdumpInformation(address=address,
library=lib,
symbol=symbol,
offset=offset)
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