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Commit 446c1ec

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Matheus Marchinijasnell
Matheus Marchini
authored and
jasnell
committed
src, tools: add debug symbols for node internals
Before these changes, only V8 added debug symbols to Node's binary, limiting the possibilities for debugger's developers to add some features that rely on investigating Node's internal structures. These changes are a first steps towards empowering debug tools to navigate Node's internals strucutres. One example of what can be achieved with this is shown at nodejs/llnode#122 (a command which prints information about handles and requests on the queue for a core dump file). Node debug symbols are prefixed with node_dbg_. Ref: nodejs/llnode#122 PR-URL: nodejs/node#14901 Refs: nodejs/post-mortem#46 Reviewed-By: Ben Noordhuis <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: James M Snell <[email protected]>
1 parent 2346c63 commit 446c1ec

2 files changed

Lines changed: 225 additions & 1 deletion

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‎node.gyp‎

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'dependencies': [
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'node_js2c#host',
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'deps/nghttp2/nghttp2.gyp:nghttp2'
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],
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'includes': [
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# node.gyp is added to the project by default.
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'common.gypi',
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'<(SHARED_INTERMEDIATE_DIR)/node_javascript.cc',
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'<(SHARED_INTERMEDIATE_DIR)/node-debug-support.cc',
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],
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'variables': {
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}]]
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}],
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]
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}
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},
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{
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'target_name': 'node_postmortem_metadata',
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'type': 'none',
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'toolsets': ['host'],
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'actions': [
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{
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'action_name': 'gen-postmortem-metadata',
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'process_outputs_as_sources': 1,
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'inputs': [
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'./tools/gen-postmortem-metadata.py',
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],
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'outputs': [
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'<(SHARED_INTERMEDIATE_DIR)/node-debug-support.cc',
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],
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'action': [
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'python',
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'./tools/gen-postmortem-metadata.py',
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'<@(_outputs)',
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]
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}
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]
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},
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], # end targets
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'conditions': [

‎tools/gen-postmortem-metadata.py‎

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#!/usr/bin/env python
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#
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# gen-postmortem-metadata.py output_file.cc
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#
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# Creates debugging symbols to help naviage Node's internals using post-mortem
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# debugging tools.
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#
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import os
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import fnmatch
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import re
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from glob import glob
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import sys
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class DebugSymbol(object):
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type_ = 'int'
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_prefix = 'nodedbg_'
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def __init__(self, name, value, headers=[], type_=None):
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self.name = name
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self.value = value
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self.headers = headers
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self.type_ = type_ or DebugSymbol.type_
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@classmethod
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def get_headers(cls, debug_symbols):
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'''
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Return a list of headers without duplicates, preserving the order they were
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declared
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'''
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seen = set()
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headers = [debug_symbol.headers for debug_symbol in debug_symbols]
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headers = sum(headers, [])
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result = []
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for h in headers:
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if not h in seen:
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seen.add(h)
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result.append(h)
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return result
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@property
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def declare(self):
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return '{type} {prefix}{name};'.format(
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type=self.type_,
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prefix=self._prefix,
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name=self.name,
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)
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@property
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def fill(self):
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return '{prefix}{name} = {value};'.format(
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prefix=self._prefix,
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name=self.name,
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value=self.value,
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)
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debug_symbols = [
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DebugSymbol(
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name='environment_context_idx_embedder_data',
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value='Environment::kContextEmbedderDataIndex',
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headers=['env.h'],
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type_='int',
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),
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DebugSymbol(
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name='class__BaseObject__persistent_handle',
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value='offsetof(BaseObject, persistent_handle_)',
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headers=['base_object-inl.h'],
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type_='size_t',
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),
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DebugSymbol(
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name='class__Environment__handleWrapQueue',
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value='offsetof(Environment, handle_wrap_queue_)',
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headers=['env.h'],
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type_='size_t',
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),
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DebugSymbol(
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name='class__HandleWrap__node',
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value='offsetof(HandleWrap, handle_wrap_queue_)',
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headers=['handle_wrap.h'],
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type_='size_t',
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),
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DebugSymbol(
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name='class__HandleWrapQueue__headOffset',
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value='offsetof(Environment::HandleWrapQueue, head_)',
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headers=['env.h'],
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type_='size_t',
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),
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DebugSymbol(
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name='class__HandleWrapQueue__nextOffset',
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value='offsetof(ListNode<HandleWrap>, next_)',
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headers=['handle_wrap.h', 'util.h'],
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type_='size_t',
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),
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DebugSymbol(
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name='class__Environment__reqWrapQueue',
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value='offsetof(Environment, req_wrap_queue_)',
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headers=['env.h'],
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type_='size_t',
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),
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DebugSymbol(
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name='class__ReqWrap__node',
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value='offsetof(ReqWrap<uv_req_t>, req_wrap_queue_)',
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headers=['req_wrap.h'],
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type_='size_t',
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),
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DebugSymbol(
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name='class__ReqWrapQueue__headOffset',
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value='offsetof(Environment::ReqWrapQueue, head_)',
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headers=['env.h'],
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type_='size_t',
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),
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DebugSymbol(
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name='class__ReqWrapQueue__nextOffset',
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value='offsetof(ListNode<ReqWrap<uv_req_t>>, next_)',
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headers=['req_wrap.h', 'util.h'],
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type_='size_t',
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),
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]
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template = '''
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/*
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* This file is generated by {filename}. Do not edit directly.
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*/
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// Need to import standard headers before redefining private, otherwise it
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// won't compile
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{standard_includes}
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int GenDebugSymbol();
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#define private friend int GenDebugSymbol(); private
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{includes}
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{declare_symbols}
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namespace node {{
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int GenDebugSymbol() {{
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{fill_symbols}
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return 1;
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}}
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int debug_symbols_generated = GenDebugSymbol();
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}}
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'''
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def get_standard_includes():
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'''
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Try to find all standard C++ headers needed by node and its dependencies
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'''
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includes = set()
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regex = re.compile('#include *<([a-zA-Z0-9\-_]*)>')
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for src in ["src", "deps"]:
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for root, dirnames, filenames in os.walk(src):
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for filename in fnmatch.filter(filenames, '*.h'):
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f = open(os.path.join(root, filename), 'r')
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for line in f.readlines():
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match = regex.match(line)
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if match:
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includes.add(match.group(1))
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return sorted(includes)
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def create_symbols_file():
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out = file(sys.argv[1], 'w')
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headers = DebugSymbol.get_headers(debug_symbols)
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includes = ['#include "{0}"'.format(header) for header in headers]
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includes = '\n'.join(includes)
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standard_includes = get_standard_includes()
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standard_includes = ['#include <{0}>'.format(include) for include in standard_includes]
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standard_includes = '\n'.join(standard_includes)
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declare_symbols = '\n'.join([symbol.declare for symbol in debug_symbols])
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fill_symbols = '\n'.join([symbol.fill for symbol in debug_symbols])
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out.write(template.format(
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filename=sys.argv[0],
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includes=includes,
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standard_includes=standard_includes,
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declare_symbols=declare_symbols,
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fill_symbols=fill_symbols,
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))
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if len(sys.argv) < 2:
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print('usage: {0} output.cc'.format(sys.argv[0]))
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sys.exit(2)
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create_symbols_file()

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