diff --git a/scripts/gen-changed-entities.py b/scripts/gen-changed-entities.py
new file mode 100755
index 0000000000..bebe4249d4
--- /dev/null
+++ b/scripts/gen-changed-entities.py
@@ -0,0 +1,809 @@
+#!/usr/bin/python3
+# Copyright (C) 2018 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+''' Generate a ChangeLog style output based on the git log.
+
+This script takes two revisions as input and generates a ChangeLog style output
+for all revisions between the two revisions.  This output is intended to be an
+approximation and not the exact ChangeLog.
+
+At a high level, the script enumerates all C source files (*.c and *.h) and
+builds a tree of top level objects within macro conditionals.  The top level
+objects the script currently attempts to identify are:
+
+    - Include statements
+    - Macro definitions and undefs
+    - Declarations and definitions of variables and functions
+    - Composite types
+
+The script attempts to identify quirks typically used in glibc sources such as
+the symbol hack macro calls that don't use a semicolon and tries to adjust for
+them.
+
+Known Limitations:
+
+    - Does not identify changes in or to comments.  Comments are simply stripped
+      out.
+    - Weird nesting of macro conditionals may break things.  Attempts have been
+      made to try and maintain state across macro conditional scopes, but
+      there's still scope to fool the script.
+    - Does not identify changes within functions.
+'''
+import subprocess
+import sys
+import os
+import re
+from enum import Enum
+
+# General Utility functions.
+def eprint(*args, **kwargs):
+    ''' Print to stderr.
+    '''
+    print(*args, file=sys.stderr, **kwargs)
+
+
+debug = False
+def debug_print(*args, **kwargs):
+    ''' Convenience function to print diagnostic information in the program.
+    '''
+    if debug:
+        eprint(*args, **kwargs)
+
+
+def usage(name):
+    ''' Print program usage.
+    '''
+    eprint("usage: %s <from-ref> <to-ref>" % name)
+    sys.exit(os.EX_USAGE)
+
+
+def decode(string):
+    ''' Attempt to decode a string.
+
+    Decode a string read from the source file.  The multiple attempts are needed
+    due to the presence of the page break characters and some tests in locales.
+    '''
+    codecs = ['utf8', 'latin1', 'cp1252']
+
+    for i in codecs:
+        try:
+            return string.decode(i)
+        except UnicodeDecodeError:
+            pass
+
+    eprint('Failed to decode: %s' % string)
+
+
+#------------------------------------------------------------------------------
+# C Parser.
+#------------------------------------------------------------------------------
+
+
+def new_block(name, type, contents, parent):
+    '''  Create a new code block with the parent as PARENT.
+
+    The code block is a basic structure around which the tree representation of
+    the source code is built.  It has the following attributes:
+
+    - type: Any one of the following types in BLOCK_TYPE.
+    - name: A name to refer it by in the ChangeLog
+    - contents: The contents of the block.  For a block of types file or
+      macro_cond, this would be a list of blocks that it nests.  For other types
+      it is a list with a single string specifying its contents.
+    - parent: This is the parent of the current block, useful in setting up
+      #elif or #else blocks in the tree.
+    - matched: A flag to specify if the block in a tree has found a match in the
+      other tree to which it is being compared.
+    '''
+    block = {}
+    block['matched'] = False
+    block['name'] = name
+    block['type'] = type
+    block['contents'] = contents
+    block['parent'] = parent
+    if parent:
+        parent['contents'].append(block)
+
+    return block
+
+
+class block_type(Enum):
+    ''' Type of code block.
+    '''
+    file = 1
+    macro_cond = 2
+    macro_def = 3
+    macro_undef = 4
+    macro_include = 5
+    macro_info = 6
+    decl = 7
+    func = 8
+    composite = 9
+    macrocall = 10
+    fndecl = 11
+    assign = 12
+
+
+# A dictionary describing what each action (add, modify, delete) show up as in
+# the ChangeLog output.
+actions = {0:{'new': 'New', 'mod': 'Modified', 'del': 'Remove'},
+           block_type.file:{'new': 'New file', 'mod': 'Modified file',
+                            'del': 'Remove file'},
+           block_type.macro_cond:{'new': 'New', 'mod': 'Modified',
+                                  'del': 'Remove'},
+           block_type.macro_def:{'new': 'New macro', 'mod': 'Modified macro',
+                                 'del': 'Remove macro'},
+           block_type.macro_undef:{'new': 'Undefine', 'mod': 'Modified',
+                                   'del': 'Remove'},
+           block_type.macro_include:{'new': 'Include file', 'mod': 'Modified',
+                                     'del': 'Remove include'},
+           block_type.macro_info:{'new': 'New preprocessor message',
+                                  'mod': 'Modified', 'del': 'Remove'},
+           block_type.decl:{'new': 'New', 'mod': 'Modified', 'del': 'Remove'},
+           block_type.func:{'new': 'New function', 'mod': 'Modified function',
+                 'del': 'Remove function'},
+           block_type.composite:{'new': 'New', 'mod': 'Modified',
+                                 'del': 'Remove'},
+           block_type.macrocall:{'new': 'New', 'mod': 'Modified',
+                                 'del': 'Remove'},
+           block_type.fndecl:{'new': 'New function', 'mod': 'Modified',
+                              'del': 'Remove'},
+           block_type.assign:{'new': 'New', 'mod': 'Modified', 'del': 'Remove'}}
+
+# Regular expressions.
+
+# The __attribute__ are written in a bunch of different ways in glibc.
+ATTRIBUTE = \
+        r'((_*(attribute|ATTRIBUTE)_*(\s*\(\([^)]+\)\)|\w+))|weak_function)';
+
+# Function regex
+FUNC_RE = re.compile(ATTRIBUTE + r'*\s*(\w+)\s*\([^(][^{]+\)\s*{')
+
+# The macrocall_re peeks into the next line to ensure that it doesn't eat up
+# a FUNC by accident.  The func_re regex is also quite crude and only
+# intends to ensure that the function name gets picked up correctly.
+MACROCALL_RE = re.compile(r'(\w+)\s*\((?!void).(\s*,\s*[\w\.]+)*\)$')
+
+# Composite types such as structs and unions.
+COMPOSITE_RE = re.compile(r'(struct|union|enum)\s*(\w*)\s*{')
+
+# Static assignments.
+ASSIGN_RE = re.compile(r'(\w+)\s*(\[[^\]]*\])*\s*([^\s]*attribute[\s\w()]+)?\s*=')
+
+# Function Declarations.
+FNDECL_RE = re.compile(r'(\w+)\s*\([^;]+\)\s*' + ATTRIBUTE + '*;')
+
+# Function pointer typedefs.
+TYPEDEF_FN_RE = re.compile(r'\(\*(\w+)\)\s*\([^)]+\);')
+
+# Simple decls.
+DECL_RE = re.compile(r'(\w+)(\[\w+\])?\s*' + ATTRIBUTE + '?;')
+
+
+def remove_comments(op):
+    ''' Remove comments.
+
+    Return OP by removing all comments from it.
+    '''
+    debug_print('REMOVE COMMENTS')
+
+    sep='\n'
+    opstr = sep.join(op)
+    opstr = re.sub(r'/\*.*?\*/', r'', opstr, flags=re.MULTILINE | re.DOTALL)
+    opstr = re.sub(r'\\\n', r' ', opstr, flags=re.MULTILINE | re.DOTALL)
+    new_op = list(filter(None, opstr.split(sep)))
+
+    return new_op
+
+
+# Parse macros.
+def parse_preprocessor(op, loc, code, start = '', else_start = ''):
+    ''' Parse a preprocessor directive.
+
+    In case a preprocessor condition (i.e. if/elif/else), create a new code
+    block to nest code into and in other cases, identify and add entities suchas
+    include files, defines, etc.
+
+    - NAME is the name of the directive
+    - CUR is the string to consume this expression from
+    - OP is the string array for the file
+    - LOC is the first unread location in CUR
+    - CODE is the block to which we add this function
+
+    - Returns: The next location to be read in the array.
+    '''
+    cur = op[loc]
+    loc = loc + 1
+    endblock = False
+
+    debug_print('PARSE_MACRO: %s' % cur)
+
+    # Remove the # and strip spaces again.
+    cur = cur[1:]
+
+    # Include file.
+    if cur.find('include') == 0:
+        m = re.search(r'include\s*["<]?([^">]+)[">]?', cur)
+        new_block(m.group(1), block_type.macro_include, [cur], code)
+
+    # Macro definition.
+    if cur.find('define') == 0:
+        m = re.search(r'define\s+([a-zA-Z0-9_]+)', cur)
+        new_block(m.group(1), block_type.macro_def, [cur], code)
+
+    # Macro undef.
+    if cur.find('undef') == 0:
+        m = re.search(r'undef\s+([a-zA-Z0-9_]+)', cur)
+        new_block(m.group(1), block_type.macro_undef, [cur], code)
+
+    # #error and #warning macros.
+    if cur.find('error') == 0 or cur.find('warning') == 0:
+        m = re.search(r'(error|warning)\s+"?(.*)"?', cur)
+        if m:
+            name = m.group(2)
+        else:
+            name = '<blank>'
+        new_block(name, block_type.macro_info, [cur], code)
+
+    # Start of an #if or #ifdef block.
+    elif cur.find('if') == 0:
+        rem = re.sub(r'ifndef', r'!', cur).strip()
+        rem = re.sub(r'(ifdef|defined|if)', r'', rem).strip()
+        ifdef = new_block(rem, block_type.macro_cond, [], code)
+        loc = c_parse(op, loc, ifdef, start)
+
+    # End the previous #if/#elif and begin a new block.
+    elif cur.find('elif') == 0 and code['parent']:
+        rem = re.sub(r'(elif|defined)', r'', cur).strip()
+        # The #else and #elif blocks should go into the current block's parent.
+        ifdef = new_block(rem, block_type.macro_cond, [], code['parent'])
+        loc = c_parse(op, loc, ifdef, else_start)
+        endblock = True
+
+    # End the previous #if/#elif and begin a new block.
+    elif cur.find('else') == 0 and code['parent']:
+        name = '!(' + code['name'] + ')'
+        ifdef = new_block(name, block_type.macro_cond, [], code['parent'])
+        loc = c_parse(op, loc, ifdef, else_start)
+        endblock = True
+
+    elif cur.find('endif') == 0 and code['parent']:
+        endblock = True
+
+    return (loc, endblock)
+
+
+# Given the start of a scope CUR, lap up all code up to the end of scope
+# indicated by the closing brace.
+def fast_forward_scope(cur, op, loc):
+    ''' Consume lines in a code block.
+
+    Consume all lines of a block of code such as a composite type declaration or
+    a function declaration.
+
+    - CUR is the string to consume this expression from
+    - OP is the string array for the file
+    - LOC is the first unread location in CUR
+
+    - Returns: The next location to be read in the array as well as the updated
+      value of CUR, which will now have the body of the function or composite
+      type.
+    '''
+    nesting = cur.count('{') - cur.count('}')
+    while nesting > 0 and loc < len(op):
+        cur = cur + ' ' + op[loc]
+
+        nesting = nesting + op[loc].count('{')
+        nesting = nesting - op[loc].count('}')
+        loc = loc + 1
+
+    return (cur, loc)
+
+
+# Different types of declarations.
+def parse_decl(name, cur, op, loc, code, blocktype):
+    ''' Parse a top level declaration.
+
+    All types of declarations except function declarations.
+
+    - NAME is the name of the declarated entity
+    - CUR is the string to consume this expression from
+    - OP is the string array for the file
+    - LOC is the first unread location in CUR
+    - CODE is the block to which we add this function
+
+    - Returns: The next location to be read in the array.
+    '''
+    debug_print('FOUND DECL: %s' % name)
+    new_block(name, blocktype, [cur], code)
+
+    return loc
+
+
+# Assignments.
+def parse_assign(name, cur, op, loc, code, blocktype):
+    ''' Parse an assignment statement.
+
+    This includes array assignments.
+
+    - NAME is the name of the assigned entity
+    - CUR is the string to consume this expression from
+    - OP is the string array for the file
+    - LOC is the first unread location in CUR
+    - CODE is the block to which we add this
+
+    - Returns: The next location to be read in the array.
+    '''
+    debug_print('FOUND ASSIGN: %s' % name)
+    # Lap up everything up to semicolon.
+    while ';' not in cur and loc < len(op):
+        cur = op[loc]
+        loc = loc + 1
+
+    new_block(name, blocktype, [cur], code)
+
+    return loc
+
+
+def parse_composite(name, cur, op, loc, code, blocktype):
+    ''' Parse a composite type.
+
+    Match declaration of a composite type such as a sruct or a union..
+
+    - NAME is the name of the composite type
+    - CUR is the string to consume this expression from
+    - OP is the string array for the file
+    - LOC is the first unread location in CUR
+    - CODE is the block to which we add this
+
+    - Returns: The next location to be read in the array.
+    '''
+    if not name:
+        name = '<anonymous>'
+
+    # Lap up all of the struct definition.
+    (cur, loc) = fast_forward_scope(cur, op, loc)
+
+    new_block(name, blocktype, [cur], code)
+
+    return loc
+
+
+def parse_func(name, cur, op, loc, code, blocktype):
+    ''' Parse a function.
+
+    Match a function definition.
+
+    - NAME is the name of the function
+    - CUR is the string to consume this expression from
+    - OP is the string array for the file
+    - LOC is the first unread location in CUR
+    - CODE is the block to which we add this
+
+    - Returns: The next location to be read in the array.
+    '''
+    debug_print('FOUND FUNC: %s' % name)
+
+    # Consume everything up to the ending brace of the function.
+    (cur, loc) = fast_forward_scope(cur, op, loc)
+
+    new_block(name, blocktype, [cur], code)
+
+    return loc
+
+
+def parse_macrocall(name, cur, op, loc, code, blocktype):
+    ''' Parse a macro call.
+
+    Match a symbol hack macro calls that get added without semicolons.
+
+    - NAME is the name of the macro call
+    - CUR is the string array for the file
+    - CUR is the string to consume this expression from
+    - OP is the string array for the file
+    - CODE is the block to which we add this
+
+    - Returns: The next location to be read in the array.
+    '''
+    debug_print('FOUND MACROCALL: %s' % name)
+
+    new_block(name, blocktype, [cur], code)
+
+    return loc
+
+
+# Regular expressions and token consumption functions for expressions we
+# encounter in C.
+c_expr_parsers = [
+        {'regex' : COMPOSITE_RE, 'func' : parse_composite, 'name' : 2,
+            'type' : block_type.composite},
+        {'regex' : ASSIGN_RE, 'func' : parse_assign, 'name' : 1,
+            'type' : block_type.assign},
+        {'regex' : TYPEDEF_FN_RE, 'func' : parse_decl, 'name' : 1,
+            'type' : block_type.decl},
+        {'regex' : FNDECL_RE, 'func' : parse_decl, 'name' : 1,
+            'type' : block_type.fndecl},
+        {'regex' : FUNC_RE, 'func' : parse_func, 'name' : 5,
+            'type' : block_type.func},
+        {'regex' : MACROCALL_RE, 'func' : parse_macrocall, 'name' : 1,
+            'type' : block_type.macrocall},
+        {'regex' : DECL_RE, 'func' : parse_decl, 'name' : 1,
+            'type' : block_type.decl}]
+
+
+def parse_c_expr(cur, op, loc, code):
+    ''' Parse a C expression.
+
+    CUR is the string to be parsed, which continues to grow until a match is
+    found.  OP is the string array and LOC is the first unread location in the
+    string array.  CODE is the block in which any identified expressions should
+    be added.
+    '''
+    debug_print('PARSING: %s' % cur)
+
+    for p in c_expr_parsers:
+        found = re.search(p['regex'], cur)
+        if found:
+            return '', p['func'](found.group(p['name']), cur, op, loc, code,
+                                    p['type'])
+
+    return cur, loc
+
+
+def c_parse(op, loc, code, start = ''):
+    '''
+    Parse the file line by line.  The function assumes a mostly GNU coding
+    standard compliant input so it might barf with anything that is eligible for
+    the Obfuscated C code contest.
+
+    The basic idea of the parser is to identify macro conditional scopes and
+    definitions, includes, etc. and then parse the remaining C code in the
+    context of those macro scopes.  The parser does not try to understand the
+    semantics of the code or even validate its syntax.  It only records high
+    level symbols in the source and makes a tree structure to indicate the
+    declaration/definition of those symbols and their scope in the macro
+    definitions.
+
+    LOC is the first unparsed line.
+    '''
+    cur = start
+    endblock = False
+
+    while loc < len(op):
+        nextline = op[loc]
+
+        # Macros.
+        if nextline[0] == '#':
+            (loc, endblock) = parse_preprocessor(op, loc, code, cur, start)
+            if endblock and not cur:
+                return loc
+        # Rest of C Code.
+        else:
+            cur = cur + ' ' + nextline
+            cur, loc = parse_c_expr(cur, op, loc + 1, code)
+
+    return loc
+
+
+def c_parse_output(op):
+    ''' File parser.
+
+    Parse the input array of lines OP and generate a tree structure to
+    represent the file.  This tree structure is then used for comparison between
+    the old and new file.
+    '''
+    tree = new_block('', block_type.file, [], None)
+    op = remove_comments(op)
+    op = [re.sub(r'#\s+', '#', x) for x in op]
+    op = c_parse(op, 0, tree)
+
+    return tree
+
+
+def print_change(tree, action, prologue = ''):
+    ''' Print the nature of the differences found in the tree compared to the
+    other tree.  TREE is the tree that changed, action is what the change was
+    (Added, Removed, Modified) and prologue specifies the macro scope the change
+    is in.  The function calls itself recursively for all macro condition tree
+    nodes.
+    '''
+
+    if tree['type'] != block_type.macro_cond:
+        print('\t%s(%s): %s.' % (prologue, tree['name'], action))
+        return
+
+    prologue = '%s[%s]' % (prologue, tree['name'])
+    for t in tree['contents']:
+        if t['type'] == block_type.macro_cond:
+            print_change(t, action, prologue)
+        else:
+            print('\t%s(%s): %s.' % (prologue, t['name'], action))
+
+
+def c_compare_trees(left, right, prologue = ''):
+    ''' Compare two trees and print the difference.
+
+    This routine is the entry point to compare two trees and print out their
+    differences.  LEFT and RIGHT will always have the same name and type,
+    starting with block_type.file and '' at the top level.
+    '''
+
+    if left['type'] == block_type.macro_cond or left['type'] == block_type.file:
+
+        if left['type'] == block_type.macro_cond:
+            prologue = '%s[%s]' % (prologue, left['name'])
+
+        # Make sure that everything in the left tree exists in the right tree.
+        for cl in left['contents']:
+            found = False
+            for cr in right['contents']:
+                if not cl['matched'] and not cr['matched'] and \
+                        cl['name'] == cr['name'] and cl['type'] == cr['type']:
+                    cl['matched'] = cr['matched'] = True
+                    c_compare_trees(cl, cr, prologue)
+                    found = True
+                    break
+            if not found:
+                print_change(cl, actions[cl['type']]['del'], prologue)
+
+        # ... and vice versa.  This time we only need to look at unmatched
+        # contents.
+        for cr in right['contents']:
+            if not cr['matched']:
+                print_change(cr, actions[cr['type']]['new'], prologue)
+    else:
+        if left['contents'] != right['contents']:
+            print_change(left, actions[left['type']]['mod'], prologue)
+
+
+def c_dump_tree(tree, indent):
+    ''' Print the entire tree.
+    '''
+    if not debug:
+        return
+
+    if tree['type'] == block_type.macro_cond or tree['type'] == block_type.file:
+        print('%sScope: %s' % (' ' * indent, tree['name']))
+        for c in tree['contents']:
+            c_dump_tree(c, indent + 4)
+        print('%sEndScope: %s' % (' ' * indent, tree['name']))
+    else:
+        if tree['type'] == block_type.func:
+            print('%sFUNC: %s' % (' ' * indent, tree['name']))
+        elif tree['type'] == block_type.composite:
+            print('%sCOMPOSITE: %s' % (' ' * indent, tree['name']))
+        elif tree['type'] == block_type.assign:
+            print('%sASSIGN: %s' % (' ' * indent, tree['name']))
+        elif tree['type'] == block_type.fndecl:
+            print('%sFNDECL: %s' % (' ' * indent, tree['name']))
+        elif tree['type'] == block_type.decl:
+            print('%sDECL: %s' % (' ' * indent, tree['name']))
+        elif tree['type'] == block_type.macrocall:
+            print('%sMACROCALL: %s' % (' ' * indent, tree['name']))
+        elif tree['type'] == block_type.macro_def:
+            print('%sDEFINE: %s' % (' ' * indent, tree['name']))
+        elif tree['type'] == block_type.macro_include:
+            print('%sINCLUDE: %s' % (' ' * indent, tree['name']))
+        elif tree['type'] == block_type.macro_undef:
+            print('%sUNDEF: %s' % (' ' * indent, tree['name']))
+        else:
+            print('%sMACRO LEAF: %s' % (' ' * indent, tree['name']))
+
+
+def c_compare(oldfile, newfile):
+    ''' Entry point for the C backend.
+
+    Parse the two files into trees and compare them.  Print the result of the
+    comparison in the ChangeLog-like format.
+    '''
+    left = c_parse_output(oldfile)
+    right = c_parse_output(newfile)
+
+    c_compare_trees(left, right)
+
+    debug_print('LEFT TREE')
+    debug_print('-' * 80)
+    c_dump_tree(left, 0)
+    debug_print('RIGHT TREE')
+    debug_print('-' * 80)
+    c_dump_tree(right, 0)
+
+
+#------------------------------------------------------------------------------
+
+
+# Register backends for specific file extensions.
+BACKENDS = \
+        {'.c': {'compare': c_compare},
+         '.h': {'compare': c_compare}}
+
+
+def get_backend(filename):
+    ''' Get an appropriate backend for FILENAME.
+    '''
+    name, ext = os.path.splitext(filename)
+
+    if not ext in BACKENDS.keys():
+        return None
+
+    return BACKENDS[ext]
+
+
+def exec_git_cmd(args):
+    ''' Execute a git command and return its result as a list of strings.
+    '''
+    args.insert(0, 'git')
+    debug_print(args)
+    proc = subprocess.Popen(args, stdout=subprocess.PIPE)
+
+    # Clean up the output by removing trailing spaces, newlines and dropping
+    # blank lines.
+    op = [decode(x[:-1]).strip() for x in proc.stdout]
+    op = [re.sub(r'\s+', ' ', x) for x in op]
+    op = [x for x in op if x]
+    return op
+
+
+def analyze_diff(oldfile, newfile, filename):
+    ''' Parse the output of the old and new files and print the difference.
+
+    For input files OLDFILE and NEWFILE with name FILENAME, generate reduced
+    trees for them and compare them.  We limit our comparison to only C source
+    files.
+    '''
+    backend = get_backend(filename)
+
+    if not backend:
+        return
+
+    backend['compare'](exec_git_cmd(['show', oldfile]),
+                       exec_git_cmd(['show', newfile]))
+
+
+def list_changes(commit):
+    ''' List changes in a single commit.
+
+    For the input commit id COMMIT, identify the files that have changed and the
+    nature of their changes.  Print commit information in the ChangeLog format,
+    calling into helper functions as necessary.
+    '''
+
+    op = exec_git_cmd(['show', '--date=short', '--raw', commit])
+    author = ''
+    date = ''
+    merge = False
+
+    for l in op:
+        if l.find('Author:') == 0:
+            tmp=l[7:].split('<')
+            authorname = tmp[0].strip()
+            authoremail=tmp[1][:-1].strip()
+        elif l.find('Date:') == 0:
+            date=l[5:].strip()
+        elif l.find('Merge:') == 0:
+            merge = True
+
+        # We got Author and Date, so don't bother with the remaining output.
+        if author != '' and date != '':
+            break
+
+    # Find raw commit information for all non-ChangeLog files.
+    op = [x[1:] for x in op if len(x) > 0 and re.match(r'^:[0-9]+', x) \
+            and 'ChangeLog' not in x]
+
+    # It was only the ChangeLog, ignore.
+    if len(op) == 0:
+        return
+
+    print('%s  %s  <%s>\n' % (date, authorname, authoremail))
+
+    if merge:
+       print('\t MERGE COMMIT: %s\n' % commit)
+       return
+
+    print('\tCOMMIT: %s' % commit)
+
+    # Each of these lines has a space separated format like so:
+    # :<OLD MODE> <NEW MODE> <OLD REF> <NEW REF> <OPERATION> <FILE1> <FILE2>
+    #
+    # where OPERATION can be one of the following:
+    # A: File added
+    # D: File removed
+    # M[0-9]{3}: File modified
+    # R[0-9]{3}: File renamed, with the 3 digit number following it indicating
+    # what percentage of the file is intact.
+    # C[0-9]{3}: File copied.  Same semantics as R.
+    # T: The permission bits of the file changed
+    # U: Unmerged.  We should not encounter this, so we ignore it/
+    # X, or anything else: Most likely a bug.  Report it.
+    #
+    # FILE2 is set only when OPERATION is R or C, to indicate the new file name.
+    #
+    # Also note that merge commits have a different format here, with three
+    # entries each for the modes and refs, but we don't bother with it for now.
+    #
+    # For more details: https://git-scm.com/docs/diff-format
+    for f in op:
+        data = f.split()
+        if data[4] == 'A':
+            print('\t* %s: New file.' % data[5])
+        elif data[4] == 'D':
+            print('\t* %s: Delete file.' % data[5])
+        elif data[4] == 'T':
+            print('\t* %s: Changed file permission bits from %s to %s' % \
+                    (data[5], data[0], data[1]))
+        elif data[4][0] == 'M':
+            print('\t* %s: Modified.' % data[5])
+            analyze_diff(data[2], data[3], data[5])
+        elif data[4][0] == 'R' or data[4][0] == 'C':
+            change = int(data[4][1:])
+            print('\t* %s: Move to...' % data[5])
+            print('\t* %s: ... here.' % data[6])
+            if change < 100:
+                analyze_diff(data[2], data[3], data[6])
+        # We should never encounter this, so ignore for now.
+        elif data[4] == 'U':
+            pass
+        else:
+            eprint('%s: Unknown line format %s' % (commit, data[4]))
+            sys.exit(42)
+
+    print('')
+
+
+def list_commits(revs):
+    ''' List commit IDs between the two revs in the REVS list.
+    '''
+    ref = revs[0] + '..' + revs[1]
+    return exec_git_cmd(['log', '--pretty=%H', ref])
+
+
+def main(revs):
+    ''' ChangeLog Generator Entry Point.
+    '''
+    commits = list_commits(revs)
+    for commit in commits:
+        list_changes(commit)
+
+
+def backend_file_test(f):
+    ''' Parser debugger Entry Point.
+    '''
+    backend = get_backend(f)
+
+    if not backend:
+        debug_print('%s: No backend for this file type, cannot debug' % f)
+        return
+
+    with open(f) as srcfile:
+        op = srcfile.readlines()
+        op = [x[:-1] for x in op]
+        tree = backend['parse_output'](op)
+        backend['dump_tree'](tree, 0)
+
+
+# Program Entry point.  If -d is specified, the second argument is assumed to be
+# a file and only the backend for the file is run in verbose mode.
+if __name__ == '__main__':
+    if len(sys.argv) != 3:
+        usage(sys.argv[0])
+
+    if sys.argv[1] == '-d':
+        debug = True
+        backend_file_test(sys.argv[2])
+    else:
+        main(sys.argv[1:])
