emsymbolizer.py - external/github.com/emscripten-core/emscripten.git - Git at Google

 #!/usr/bin/env python3

 # This is a utility for looking up the symbol names and/or file+line numbers
 # of code addresses. There are several possible sources of this information,
 # with varying granularity (listed here in approximate preference order).

 # If the wasm has DWARF info, llvm-symbolizer can show the symbol, file, and
 # line/column number, potentially including inlining.
 # If the wasm has separate DWARF info, do the above with the side file
 # If there is a source map, we can parse it to get file and line number.
 # If there is an emscripten symbol map, we can use that to get the symbol name
 # If there is a name section or symbol table, llvm-symbolizer can show the
 #  symbol name.
 # Separate DWARF and emscripten symbol maps are not supported yet.

 import argparse
 import json
 import os
 import re
 import subprocess
 import sys
 from tools import shared
 from tools import webassembly

 LLVM_SYMBOLIZER = os.path.expanduser(
     shared.build_llvm_tool_path(shared.exe_suffix('llvm-symbolizer')))


 class Error(BaseException):
   pass


 # Class to treat location info in a uniform way across information sources.
 class LocationInfo(object):
   def __init__(self, source=None, line=0, column=0, func=None):
     self.source = source
     self.line = line
     self.column = column
     self.func = func

   def print(self):
     source = self.source if self.source else '??'
     func = self.func if self.func else '??'
     print(f'{func}\n{source}:{self.line}:{self.column}')


 def get_codesec_offset(module):
   sec = module.get_section(webassembly.SecType.CODE)
   if not sec:
     raise Error(f'No code section found in {module.filename}')
   return sec.offset


 def has_debug_line_section(module):
   return module.get_custom_section('.debug_line') is not None


 def has_name_section(module):
   return module.get_custom_section('name') is not None


 def has_linking_section(module):
   return module.get_custom_section('linking') is not None


 def symbolize_address_symbolizer(module, address, is_dwarf):
   if is_dwarf:
     vma_adjust = get_codesec_offset(module)
   else:
     vma_adjust = 0
   cmd = [LLVM_SYMBOLIZER, '-e', module.filename, f'--adjust-vma={vma_adjust}',
          str(address)]
   out = shared.run_process(cmd, stdout=subprocess.PIPE).stdout.strip()
   out_lines = out.splitlines()

   # Source location regex, e.g., /abc/def.c:3:5
   SOURCE_LOC_RE = re.compile(r'(.+):(\d+):(\d+)$')
   # llvm-symbolizer prints two lines per location. The first line contains a
   # function name, and the second contains a source location like
   # '/abc/def.c:3:5'. If the function or source info is not available, it will
   # be printed as '??', in which case we store None. If the line and column info
   # is not available, they will be printed as 0, which we store as is.
   for i in range(0, len(out_lines), 2):
     func, loc_str = out_lines[i], out_lines[i + 1]
     m = SOURCE_LOC_RE.match(loc_str)
     source, line, column = m.group(1), m.group(2), m.group(3)
     if func == '??':
       func = None
     if source == '??':
       source = None
     LocationInfo(source, line, column, func).print()


 def get_sourceMappingURL_section(module):
   for sec in module.sections():
     if sec.name == "sourceMappingURL":
       return sec
   return None


 class WasmSourceMap(object):
   class Location(object):
     def __init__(self, source=None, line=0, column=0, func=None):
       self.source = source
       self.line = line
       self.column = column
       self.func = func

   def __init__(self):
     self.version = None
     self.sources = []
     self.mappings = {}
     self.offsets = []

   def parse(self, filename):
     with open(filename) as f:
       source_map_json = json.loads(f.read())
       if shared.DEBUG:
         print(source_map_json)

     self.version = source_map_json['version']
     self.sources = source_map_json['sources']

     chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='
     vlq_map = {c: i for i, c in enumerate(chars)}

     def decodeVLQ(string):
       result = []
       shift = 0
       value = 0
       for c in string:
         try:
           integer = vlq_map[c]
         except ValueError as e:
           raise Error(f'Invalid character ({c}) in VLQ') from e
         value += (integer & 31) << shift
         if integer & 32:
           shift += 5
         else:
           negate = value & 1
           value >>= 1
           result.append(-value if negate else value)
           value = shift = 0
       return result

     offset = 0
     src = 0
     line = 1
     col = 1
     for segment in source_map_json['mappings'].split(','):
       data = decodeVLQ(segment)
       info = []

       offset += data[0]
       if len(data) >= 2:
         src += data[1]
         info.append(src)
       if len(data) >= 3:
         line += data[2]
         info.append(line)
       if len(data) >= 4:
         col += data[3]
         info.append(col)
       # TODO: see if we need the name, which is the next field (data[4])

       self.mappings[offset] = WasmSourceMap.Location(*info)
       self.offsets.append(offset)
     self.offsets.sort()

   def find_offset(self, offset):
     # Find the largest mapped offset <= the search offset
     lo = 0
     hi = len(self.offsets)

     while lo < hi:
       mid = (lo + hi) // 2
       if self.offsets[mid] > offset:
         hi = mid
       else:
         lo = mid + 1
     return self.offsets[lo - 1]

   def lookup(self, offset):
     nearest = self.find_offset(offset)
     assert nearest in self.mappings, 'Sourcemap has an offset with no mapping'
     info = self.mappings[nearest]
     return LocationInfo(
         self.sources[info.source] if info.source is not None else None,
         info.line,
         info.column
       )


 def symbolize_address_sourcemap(module, address, force_file):
   URL = force_file
   if not URL:
     # If a sourcemap file is not forced, read it from the wasm module
     section = get_sourceMappingURL_section(module)
     assert section
     module.seek(section.offset)
     assert module.read_string() == 'sourceMappingURL'
     # TODO: support stripping/replacing a prefix from the URL
     URL = module.read_string()

   if shared.DEBUG:
     print(f'Source Mapping URL: {URL}')
   sm = WasmSourceMap()
   sm.parse(URL)
   if shared.DEBUG:
     csoff = get_codesec_offset(module)
     print(sm.mappings)
     # Print with section offsets to easily compare against dwarf
     for k, v in sm.mappings.items():
       print(f'{k-csoff:x}: {v}')
   sm.lookup(address).print()


 def main(args):
   with webassembly.Module(args.wasm_file) as module:
     base = 16 if args.address.lower().startswith('0x') else 10
     address = int(args.address, base)

     if args.addrtype == 'code':
       address += get_codesec_offset(module)

     if ((has_debug_line_section(module) and not args.source) or
        'dwarf' in args.source):
       symbolize_address_symbolizer(module, address, is_dwarf=True)
     elif ((get_sourceMappingURL_section(module) and not args.source) or
           'sourcemap' in args.source):
       symbolize_address_sourcemap(module, address, args.file)
     elif ((has_name_section(module) and not args.source) or
           'names' in args.source):
       symbolize_address_symbolizer(module, address, is_dwarf=False)
     elif ((has_linking_section(module) and not args.source) or
           'symtab' in args.source):
       symbolize_address_symbolizer(module, address, is_dwarf=False)
     else:
       raise Error('No .debug_line or sourceMappingURL section found in '
                   f'{module.filename}.'
                   " I don't know how to symbolize this file yet")


 def get_args():
   parser = argparse.ArgumentParser()
   parser.add_argument('-s', '--source', choices=['dwarf', 'sourcemap',
                                                  'names', 'symtab'],
                       help='Force debug info source type', default=())
   parser.add_argument('-f', '--file', action='store',
                       help='Force debug info source file')
   parser.add_argument('-t', '--addrtype', choices=['code', 'file'],
                       default='file',
                       help='Address type (code section or file offset)')
   parser.add_argument('-v', '--verbose', action='store_true',
                       help='Print verbose info for debugging this script')
   parser.add_argument('wasm_file', help='Wasm file')
   parser.add_argument('address', help='Address to lookup')
   args = parser.parse_args()
   if args.verbose:
     shared.PRINT_SUBPROCS = 1
     shared.DEBUG = True
   return args


 if __name__ == '__main__':
   try:
     rv = main(get_args())
   except (Error, webassembly.InvalidWasmError, OSError) as e:
     print(f'{sys.argv[0]}: {str(e)}', file=sys.stderr)
     rv = 1
   sys.exit(rv)
	#!/usr/bin/env python3

	# This is a utility for looking up the symbol names and/or file+line numbers
	# of code addresses. There are several possible sources of this information,
	# with varying granularity (listed here in approximate preference order).

	# If the wasm has DWARF info, llvm-symbolizer can show the symbol, file, and
	# line/column number, potentially including inlining.
	# If the wasm has separate DWARF info, do the above with the side file
	# If there is a source map, we can parse it to get file and line number.
	# If there is an emscripten symbol map, we can use that to get the symbol name
	# If there is a name section or symbol table, llvm-symbolizer can show the
	# symbol name.
	# Separate DWARF and emscripten symbol maps are not supported yet.

	import argparse
	import json
	import os
	import re
	import subprocess
	import sys
	from tools import shared
	from tools import webassembly

	LLVM_SYMBOLIZER = os.path.expanduser(
	shared.build_llvm_tool_path(shared.exe_suffix('llvm-symbolizer')))


	class Error(BaseException):
	pass


	# Class to treat location info in a uniform way across information sources.
	class LocationInfo(object):
	def __init__(self, source=None, line=0, column=0, func=None):
	self.source = source
	self.line = line
	self.column = column
	self.func = func

	def print(self):
	source = self.source if self.source else '??'
	func = self.func if self.func else '??'
	print(f'{func}\n{source}:{self.line}:{self.column}')


	def get_codesec_offset(module):
	sec = module.get_section(webassembly.SecType.CODE)
	if not sec:
	raise Error(f'No code section found in {module.filename}')
	return sec.offset


	def has_debug_line_section(module):
	return module.get_custom_section('.debug_line') is not None


	def has_name_section(module):
	return module.get_custom_section('name') is not None


	def has_linking_section(module):
	return module.get_custom_section('linking') is not None


	def symbolize_address_symbolizer(module, address, is_dwarf):
	if is_dwarf:
	vma_adjust = get_codesec_offset(module)
	else:
	vma_adjust = 0
	cmd = [LLVM_SYMBOLIZER, '-e', module.filename, f'--adjust-vma={vma_adjust}',
	str(address)]
	out = shared.run_process(cmd, stdout=subprocess.PIPE).stdout.strip()
	out_lines = out.splitlines()

	# Source location regex, e.g., /abc/def.c:3:5
	SOURCE_LOC_RE = re.compile(r'(.+):(\d+):(\d+)$')
	# llvm-symbolizer prints two lines per location. The first line contains a
	# function name, and the second contains a source location like
	# '/abc/def.c:3:5'. If the function or source info is not available, it will
	# be printed as '??', in which case we store None. If the line and column info
	# is not available, they will be printed as 0, which we store as is.
	for i in range(0, len(out_lines), 2):
	func, loc_str = out_lines[i], out_lines[i + 1]
	m = SOURCE_LOC_RE.match(loc_str)
	source, line, column = m.group(1), m.group(2), m.group(3)
	if func == '??':
	func = None
	if source == '??':
	source = None
	LocationInfo(source, line, column, func).print()


	def get_sourceMappingURL_section(module):
	for sec in module.sections():
	if sec.name == "sourceMappingURL":
	return sec
	return None


	class WasmSourceMap(object):
	class Location(object):
	def __init__(self, source=None, line=0, column=0, func=None):
	self.source = source
	self.line = line
	self.column = column
	self.func = func

	def __init__(self):
	self.version = None
	self.sources = []
	self.mappings = {}
	self.offsets = []

	def parse(self, filename):
	with open(filename) as f:
	source_map_json = json.loads(f.read())
	if shared.DEBUG:
	print(source_map_json)

	self.version = source_map_json['version']
	self.sources = source_map_json['sources']

	chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='
	vlq_map = {c: i for i, c in enumerate(chars)}

	def decodeVLQ(string):
	result = []
	shift = 0
	value = 0
	for c in string:
	try:
	integer = vlq_map[c]
	except ValueError as e:
	raise Error(f'Invalid character ({c}) in VLQ') from e
	value += (integer & 31) << shift
	if integer & 32:
	shift += 5
	else:
	negate = value & 1
	value >>= 1
	result.append(-value if negate else value)
	value = shift = 0
	return result

	offset = 0
	src = 0
	line = 1
	col = 1
	for segment in source_map_json['mappings'].split(','):
	data = decodeVLQ(segment)
	info = []

	offset += data[0]
	if len(data) >= 2:
	src += data[1]
	info.append(src)
	if len(data) >= 3:
	line += data[2]
	info.append(line)
	if len(data) >= 4:
	col += data[3]
	info.append(col)
	# TODO: see if we need the name, which is the next field (data[4])

	self.mappings[offset] = WasmSourceMap.Location(*info)
	self.offsets.append(offset)
	self.offsets.sort()

	def find_offset(self, offset):
	# Find the largest mapped offset <= the search offset
	lo = 0
	hi = len(self.offsets)

	while lo < hi:
	mid = (lo + hi) // 2
	if self.offsets[mid] > offset:
	hi = mid
	else:
	lo = mid + 1
	return self.offsets[lo - 1]

	def lookup(self, offset):
	nearest = self.find_offset(offset)
	assert nearest in self.mappings, 'Sourcemap has an offset with no mapping'
	info = self.mappings[nearest]
	return LocationInfo(
	self.sources[info.source] if info.source is not None else None,
	info.line,
	info.column
	)


	def symbolize_address_sourcemap(module, address, force_file):
	URL = force_file
	if not URL:
	# If a sourcemap file is not forced, read it from the wasm module
	section = get_sourceMappingURL_section(module)
	assert section
	module.seek(section.offset)
	assert module.read_string() == 'sourceMappingURL'
	# TODO: support stripping/replacing a prefix from the URL
	URL = module.read_string()

	if shared.DEBUG:
	print(f'Source Mapping URL: {URL}')
	sm = WasmSourceMap()
	sm.parse(URL)
	if shared.DEBUG:
	csoff = get_codesec_offset(module)
	print(sm.mappings)
	# Print with section offsets to easily compare against dwarf
	for k, v in sm.mappings.items():
	print(f'{k-csoff:x}: {v}')
	sm.lookup(address).print()


	def main(args):
	with webassembly.Module(args.wasm_file) as module:
	base = 16 if args.address.lower().startswith('0x') else 10
	address = int(args.address, base)

	if args.addrtype == 'code':
	address += get_codesec_offset(module)

	if ((has_debug_line_section(module) and not args.source) or
	'dwarf' in args.source):
	symbolize_address_symbolizer(module, address, is_dwarf=True)
	elif ((get_sourceMappingURL_section(module) and not args.source) or
	'sourcemap' in args.source):
	symbolize_address_sourcemap(module, address, args.file)
	elif ((has_name_section(module) and not args.source) or
	'names' in args.source):
	symbolize_address_symbolizer(module, address, is_dwarf=False)
	elif ((has_linking_section(module) and not args.source) or
	'symtab' in args.source):
	symbolize_address_symbolizer(module, address, is_dwarf=False)
	else:
	raise Error('No .debug_line or sourceMappingURL section found in '
	f'{module.filename}.'
	" I don't know how to symbolize this file yet")


	def get_args():
	parser = argparse.ArgumentParser()
	parser.add_argument('-s', '--source', choices=['dwarf', 'sourcemap',
	'names', 'symtab'],
	help='Force debug info source type', default=())
	parser.add_argument('-f', '--file', action='store',
	help='Force debug info source file')
	parser.add_argument('-t', '--addrtype', choices=['code', 'file'],
	default='file',
	help='Address type (code section or file offset)')
	parser.add_argument('-v', '--verbose', action='store_true',
	help='Print verbose info for debugging this script')
	parser.add_argument('wasm_file', help='Wasm file')
	parser.add_argument('address', help='Address to lookup')
	args = parser.parse_args()
	if args.verbose:
	shared.PRINT_SUBPROCS = 1
	shared.DEBUG = True
	return args


	if __name__ == '__main__':
	try:
	rv = main(get_args())
	except (Error, webassembly.InvalidWasmError, OSError) as e:
	print(f'{sys.argv[0]}: {str(e)}', file=sys.stderr)
	rv = 1
	sys.exit(rv)