Reland of V2 of //tools/binary_size rewrite (diffs).

tools/binary_size/models.py

Index: tools/binary_size/models.py
diff --git a/tools/binary_size/models.py b/tools/binary_size/models.py
new file mode 100644
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--- /dev/null
+++ b/tools/binary_size/models.py
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+# Copyright 2017 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+"""Classes that comprise the data model for binary size analysis."""
+
+import collections
+import copy
+import re
+
+
+SECTION_TO_SECTION_NAME = {
+    'b': '.bss',
+    'd': '.data',
+    'r': '.rodata',
+    't': '.text',
+}
+
+
+class SizeInfo(object):
+  """Represents all size information for a single binary.
+
+  Fields:
+    section_sizes: A dict of section_name -> size.
+    symbols: A SymbolGroup (or SymbolDiff) with all symbols in it.
+  """
+  __slots__ = (
+      'symbols',
+      'section_sizes',
+  )
+
+  """Root size information."""
+  def __init__(self, symbols, section_sizes):
+    self.symbols = symbols
+    self.section_sizes = section_sizes  # E.g. {'.text': 0}
+
+
+class BaseSymbol(object):
+  """Base class for Symbol and SymbolGroup."""
+  __slots__ = ()
+
+  @property
+  def section(self):
+    """Returns the one-letter section.
+
+    E.g. If section_name == '.rodata', then section == 'r'.
+    """
+    return self.section_name[1]
+
+  @property
+  def size_without_padding(self):
+    return self.size - self.padding
+
+  @property
+  def end_address(self):
+    return self.address + self.size_without_padding
+
+  def IsBss(self):
+    return self.section_name == '.bss'
+
+  def IsGroup(self):
+    return False
+
+  def IsGenerated(self):
+    # TODO(agrieve): Also match generated functions such as:
+    #     startup._GLOBAL__sub_I_page_allocator.cc
+    return self.name.endswith(']') and not self.name.endswith('[]')
+
+  def _Key(self):
+    """Returns a tuple that can be used to see if two Symbol are the same.
+
+    Keys are not guaranteed to be unique within a SymbolGroup. For example, it
+    is common to have multiple "** merge strings" symbols, which will have a
+    common key."""
+    return (self.section_name, self.function_signature or self.name)
+
+
+class Symbol(BaseSymbol):
+  """Represents a single symbol within a binary."""
+
+  __slots__ = (
+      'section_name',
+      'address',
+      'size',
+      'padding',
+      'name',
+      'function_signature',
+      'path',
+  )
+
+  def __init__(self, section_name, size_without_padding, address=None,
+               name=None, path=None, function_signature=None):
+    self.section_name = section_name
+    self.address = address or 0
+    self.name = name or ''
+    self.function_signature = function_signature or ''
+    self.path = path or ''
+    self.size = size_without_padding
+    self.padding = 0
+
+  def __repr__(self):
+    return '%s@%x(size=%d,padding=%d,name=%s,path=%s)' % (
+        self.section_name, self.address, self.size_without_padding,
+        self.padding, self.name, self.path)
+
+
+class SymbolGroup(BaseSymbol):
+  """Represents a group of symbols using the same interface as Symbol.
+
+  SymbolGroups are immutable. All filtering / sorting will return new
+  SymbolGroups objects.
+  """
+
+  __slots__ = (
+      'symbols',
+      'filtered_symbols',
+      'name',
+      'section_name',
+  )
+
+  def __init__(self, symbols, filtered_symbols=None, name=None,
+               section_name=None):
+    self.symbols = symbols
+    self.filtered_symbols = filtered_symbols or []
+    self.name = name or ''
+    self.section_name = section_name or '.*'
+
+  def __repr__(self):
+    return 'Group(name=%s,count=%d,size=%d)' % (
+        self.name, len(self), self.size)
+
+  def __iter__(self):
+    return iter(self.symbols)
+
+  def __len__(self):
+    return len(self.symbols)
+
+  def __getitem__(self, index):
+    return self.symbols[index]
+
+  def __sub__(self, other):
+    other_ids = set(id(s) for s in other)
+    new_symbols = [s for s in self if id(s) not in other_ids]
+    return self._CreateTransformed(new_symbols, section_name=self.section_name)
+
+  def __add__(self, other):
+    self_ids = set(id(s) for s in self)
+    new_symbols = self.symbols + [s for s in other if id(s) not in self_ids]
+    return self._CreateTransformed(new_symbols, section_name=self.section_name)
+
+  @property
+  def address(self):
+    return 0
+
+  @property
+  def function_signature(self):
+    return None
+
+  @property
+  def path(self):
+    return None
+
+  @property
+  def size(self):
+    if self.IsBss():
+      return sum(s.size for s in self)
+    return sum(s.size for s in self if not s.IsBss())
+
+  @property
+  def padding(self):
+    return sum(s.padding for s in self)
+
+  def IsGroup(self):
+    return True
+
+  def _CreateTransformed(self, symbols, filtered_symbols=None, name=None,
+                         section_name=None):
+    return SymbolGroup(symbols, filtered_symbols=filtered_symbols, name=name,
+                       section_name=section_name)
+
+  def Sorted(self, cmp_func=None, key=None, reverse=False):
+    # Default to sorting by abs(size) then name.
+    if cmp_func is None and key is None:
+      cmp_func = lambda a, b: cmp((a.IsBss(), abs(b.size), a.name),
+                                  (b.IsBss(), abs(a.size), b.name))
+
+    new_symbols = sorted(self.symbols, cmp_func, key, reverse)
+    return self._CreateTransformed(new_symbols,
+                                   filtered_symbols=self.filtered_symbols,
+                                   section_name=self.section_name)
+
+  def Filter(self, func):
+    filtered_and_kept = ([], [])
+    for symbol in self:
+      filtered_and_kept[int(bool(func(symbol)))].append(symbol)
+    return self._CreateTransformed(filtered_and_kept[1],
+                                   filtered_symbols=filtered_and_kept[0],
+                                   section_name=self.section_name)
+
+  def WhereBiggerThan(self, min_size):
+    return self.Filter(lambda s: s.size >= min_size)
+
+  def WhereInSection(self, section):
+    if len(section) == 1:
+      ret = self.Filter(lambda s: s.section == section)
+      ret.section_name = SECTION_TO_SECTION_NAME[section]
+    else:
+      ret = self.Filter(lambda s: s.section_name == section)
+      ret.section_name = section
+    return ret
+
+  def WhereIsGenerated(self):
+    return self.Filter(lambda s: s.IsGenerated())
+
+  def WhereNameMatches(self, pattern):
+    regex = re.compile(pattern)
+    return self.Filter(lambda s: regex.search(s.name))
+
+  def WherePathMatches(self, pattern):
+    regex = re.compile(pattern)
+    return self.Filter(lambda s: s.path and regex.search(s.path))
+
+  def WhereAddressInRange(self, start, end):
+    return self.Filter(lambda s: s.address >= start and s.address <= end)
+
+  def WhereHasAnyAttribution(self):
+    return self.Filter(lambda s: s.name or s.path)
+
+  def Inverted(self):
+    return self._CreateTransformed(self.filtered_symbols,
+                                   filtered_symbols=self.symbols)
+
+  def GroupBy(self, func):
+    new_syms = []
+    filtered_symbols = []
+    symbols_by_token = collections.defaultdict(list)
+    for symbol in self:
+      token = func(symbol)
+      if not token:
+        filtered_symbols.append(symbol)
+        continue
+      symbols_by_token[token].append(symbol)
+    for token, symbols in symbols_by_token.iteritems():
+      new_syms.append(self._CreateTransformed(symbols, name=token,
+                                              section_name=self.section_name))
+    return self._CreateTransformed(new_syms, filtered_symbols=filtered_symbols,
+                                   section_name=self.section_name)
+
+  def GroupByNamespace(self, depth=1):
+    def extract_namespace(symbol):
+      # Does not distinguish between classes and namespaces.
+      idx = -2
+      for _ in xrange(depth):
+        idx = symbol.name.find('::', idx + 2)
+      if idx != -1:
+        ret = symbol.name[:idx]
+        if '<' not in ret:
+          return ret
+      return '{global}'
+    return self.GroupBy(extract_namespace)
+
+  def GroupByPath(self, depth=1):
+    def extract_path(symbol):
+      idx = -1
+      for _ in xrange(depth):
+        idx = symbol.path.find('/', idx + 1)
+      if idx != -1:
+        return symbol.path[:idx]
+      return '{path unknown}'
+    return self.GroupBy(extract_path)
+
+
+class SymbolDiff(SymbolGroup):
+  """A SymbolGroup subclass representing a diff of two other SymbolGroups.
+
+  All Symbols contained within have a |size| which is actually the size delta.
+  Additionally, metadata is kept about which symbols were added / removed /
+  changed.
+  """
+  __slots__ = (
+      '_added_ids',
+      '_removed_ids',
+  )
+
+  def __init__(self, added, removed, similar):
+    self._added_ids = set(id(s) for s in added)
+    self._removed_ids = set(id(s) for s in removed)
+    symbols = []
+    symbols.extend(added)
+    symbols.extend(removed)
+    symbols.extend(similar)
+    super(SymbolDiff, self).__init__(symbols)
+
+  def __repr__(self):
+    return '%s(%d added, %d removed, %d changed, %d unchanged, size=%d)' % (
+        'SymbolGroup', self.added_count, self.removed_count, self.changed_count,
+        self.unchanged_count, self.size)
+
+  def _CreateTransformed(self, symbols, filtered_symbols=None, name=None,
+                         section_name=None):
+    ret = SymbolDiff.__new__(SymbolDiff)
+    # Printing sorts, so fast-path the same symbols case.
+    if len(symbols) == len(self.symbols):
+      ret._added_ids = self._added_ids
+      ret._removed_ids = self._removed_ids
+    else:
+      ret._added_ids = set(id(s) for s in symbols if self.IsAdded(s))
+      ret._removed_ids = set(id(s) for s in symbols if self.IsRemoved(s))
+    super(SymbolDiff, ret).__init__(symbols, filtered_symbols=filtered_symbols,
+                                    name=name, section_name=section_name)
+
+    return ret
+
+  @property
+  def added_count(self):
+    return len(self._added_ids)
+
+  @property
+  def removed_count(self):
+    return len(self._removed_ids)
+
+  @property
+  def changed_count(self):
+    not_changed = self.unchanged_count + self.added_count + self.removed_count
+    return len(self) - not_changed
+
+  @property
+  def unchanged_count(self):
+    return sum(1 for s in self if self.IsSimilar(s) and s.size == 0)
+
+  def IsAdded(self, sym):
+    return id(sym) in self._added_ids
+
+  def IsSimilar(self, sym):
+    key = id(sym)
+    return key not in self._added_ids and key not in self._removed_ids
+
+  def IsRemoved(self, sym):
+    return id(sym) in self._removed_ids
+
+  def WhereNotUnchanged(self):
+    return self.Filter(lambda s: not self.IsSimilar(s) or s.size)
+
+
+def Diff(new, old):
+  """Diffs two SizeInfo or SymbolGroup objects.
+
+  When diffing SizeInfos, ret.section_sizes are the result of |new| - |old|, and
+  ret.symbols will be a SymbolDiff.
+
+  When diffing SymbolGroups, a SymbolDiff is returned.
+
+  Returns:
+    Returns a SizeInfo when args are of type SizeInfo.
+    Returns a SymbolDiff when args are of type SymbolGroup.
+  """
+  if isinstance(new, SizeInfo):
+    assert isinstance(old, SizeInfo)
+    section_sizes = {
+        k:new.section_sizes[k] - v for k, v in old.section_sizes.iteritems()}
+    symbol_diff = Diff(new.symbols, old.symbols)
+    return SizeInfo(symbol_diff, section_sizes)
+
+  assert isinstance(new, SymbolGroup) and isinstance(old, SymbolGroup)
+  symbols_by_key = collections.defaultdict(list)
+  for s in old:
+    symbols_by_key[s._Key()].append(s)
+
+  added = []
+  removed = []
+  similar = []
+  # For similar symbols, padding is zeroed out. In order to not lose the
+  # information entirely, store it in aggregate.
+  padding_by_section_name = collections.defaultdict(int)
+  for new_sym in new:
+    matching_syms = symbols_by_key.get(new_sym._Key())
+    if matching_syms:
+      old_sym = matching_syms.pop(0)
+      # More stable/useful to compare size without padding.
+      size_diff = (new_sym.size_without_padding -
+                   old_sym.size_without_padding)
+      merged_sym = Symbol(old_sym.section_name, size_diff,
+                          address=old_sym.address, name=old_sym.name,
+                          path=old_sym.path,
+                          function_signature=old_sym.function_signature)
+      similar.append(merged_sym)
+      padding_by_section_name[new_sym.section_name] += (
+          new_sym.padding - old_sym.padding)
+    else:
+      added.append(new_sym)
+
+  for remaining_syms in symbols_by_key.itervalues():
+    for old_sym in remaining_syms:
+      duped = copy.copy(old_sym)
+      duped.size = -duped.size
+      duped.padding = -duped.padding
+      removed.append(duped)
+
+  for section_name, padding in padding_by_section_name.iteritems():
+    similar.append(Symbol(section_name, padding,
+                          name='** aggregate padding of delta symbols'))
+  return SymbolDiff(added, removed, similar)