config/check_spidermonkey_style.py
author Chris H-C <chutten@mozilla.com>
Mon, 04 Jul 2016 11:16:05 -0400
changeset 312997 df28918fe2361f0b54ca9ce4773a29c4c0675d06
parent 305161 86a5424096d537c318dd3d90b9f69c3dc6c85bdb
permissions -rw-r--r--
bug 1218576 - Support remote accumulation via JS histograms. r=gfritzsche The JS histograms, too, need to dispatch their accumulations from child to parent. JSHistograms_Add now only supports histograms that are in gHistogramsMap or that were created in the parent process. After bug 1288745, maybe we'll be able to change this to be less convoluted. MozReview-Commit-ID: 3qTH89YKbGP

# vim: set ts=8 sts=4 et sw=4 tw=99:
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

#----------------------------------------------------------------------------
# This script checks various aspects of SpiderMonkey code style.  The current checks are as
# follows.
#
# We check the following things in headers.
#
# - No cyclic dependencies.
#
# - No normal header should #include a inlines.h/-inl.h file.
#
# - #ifndef wrappers should have the right form. (XXX: not yet implemented)
#   - Every header file should have one.
#   - The guard name used should be appropriate for the filename.
#
# We check the following things in all files.
#
# - #includes should have full paths, e.g. "jit/Ion.h", not "Ion.h".
#
# - #includes should use the appropriate form for system headers (<...>) and
#   local headers ("...").
#
# - #includes should be ordered correctly.
#   - Each one should be in the correct section.
#   - Alphabetical order should be used within sections.
#   - Sections should be in the right order.
#   Note that the presence of #if/#endif blocks complicates things, to the
#   point that it's not always clear where a conditionally-compiled #include
#   statement should go, even to a human.  Therefore, we check the #include
#   statements within each #if/#endif block (including nested ones) in
#   isolation, but don't try to do any order checking between such blocks.
#----------------------------------------------------------------------------

from __future__ import print_function

import difflib
import os
import re
import subprocess
import sys
import traceback
from check_utils import get_all_toplevel_filenames

# We don't bother checking files in these directories, because they're (a) auxiliary or (b)
# imported code that doesn't follow our coding style.
ignored_js_src_dirs = [
   'js/src/config/',            # auxiliary stuff
   'js/src/ctypes/libffi/',     # imported code
   'js/src/devtools/',          # auxiliary stuff
   'js/src/editline/',          # imported code
   'js/src/gdb/',               # auxiliary stuff
   'js/src/vtune/'              # imported code
]

# We ignore #includes of these files, because they don't follow the usual rules.
included_inclnames_to_ignore = set([
    'ffi.h',                    # generated in ctypes/libffi/
    'devtools/sharkctl.h',      # we ignore devtools/ in general
    'devtools/Instruments.h',   # we ignore devtools/ in general
    'double-conversion.h',      # strange MFBT case
    'javascript-trace.h',       # generated in $OBJDIR if HAVE_DTRACE is defined
    'jsautokw.h',               # generated in $OBJDIR
    'jscustomallocator.h',      # provided by embedders;  allowed to be missing
    'js-config.h',              # generated in $OBJDIR
    'fdlibm.h',                 # fdlibm
    'pratom.h',                 # NSPR
    'prcvar.h',                 # NSPR
    'prerror.h',                # NSPR
    'prinit.h',                 # NSPR
    'prio.h',                   # NSPR
    'private/pprio.h',          # NSPR
    'prlink.h',                 # NSPR
    'prlock.h',                 # NSPR
    'prprf.h',                  # NSPR
    'prthread.h',               # NSPR
    'prtypes.h',                # NSPR
    'selfhosted.out.h',         # generated in $OBJDIR
    'shellmoduleloader.out.h',  # generated in $OBJDIR
    'unicode/locid.h',          # ICU
    'unicode/numsys.h',         # ICU
    'unicode/timezone.h',       # ICU
    'unicode/ucal.h',           # ICU
    'unicode/uclean.h',         # ICU
    'unicode/ucol.h',           # ICU
    'unicode/udat.h',           # ICU
    'unicode/udatpg.h',         # ICU
    'unicode/uenum.h',          # ICU
    'unicode/unorm.h',          # ICU
    'unicode/unum.h',           # ICU
    'unicode/ustring.h',        # ICU
    'unicode/utypes.h',         # ICU
    'vtune/VTuneWrapper.h'      # VTune
])

# These files have additional constraints on where they are #included, so we
# ignore #includes of them when checking #include ordering.
oddly_ordered_inclnames = set([
    'ctypes/typedefs.h',        # Included multiple times in the body of ctypes/CTypes.h
    'jsautokw.h',               # Included in the body of frontend/TokenStream.h
    'jswin.h',                  # Must be #included before <psapi.h>
    'machine/endian.h',         # Must be included after <sys/types.h> on BSD
    'winbase.h',                # Must precede other system headers(?)
    'windef.h'                  # Must precede other system headers(?)
])

# The files in tests/style/ contain code that fails this checking in various
# ways.  Here is the output we expect.  If the actual output differs from
# this, one of the following must have happened.
# - New SpiderMonkey code violates one of the checked rules.
# - The tests/style/ files have changed without expected_output being changed
#   accordingly.
# - This script has been broken somehow.
#
expected_output = '''\
js/src/tests/style/BadIncludes2.h:1: error:
    vanilla header includes an inline-header file "tests/style/BadIncludes2-inl.h"

js/src/tests/style/BadIncludes.h:3: error:
    the file includes itself

js/src/tests/style/BadIncludes.h:6: error:
    "BadIncludes2.h" is included using the wrong path;
    did you forget a prefix, or is the file not yet committed?

js/src/tests/style/BadIncludes.h:8: error:
    <tests/style/BadIncludes2.h> should be included using
    the #include "..." form

js/src/tests/style/BadIncludes.h:10: error:
    "stdio.h" is included using the wrong path;
    did you forget a prefix, or is the file not yet committed?

js/src/tests/style/BadIncludesOrder-inl.h:5:6: error:
    "vm/Interpreter-inl.h" should be included after "jsscriptinlines.h"

js/src/tests/style/BadIncludesOrder-inl.h:6:7: error:
    "jsscriptinlines.h" should be included after "js/Value.h"

js/src/tests/style/BadIncludesOrder-inl.h:7:8: error:
    "js/Value.h" should be included after "ds/LifoAlloc.h"

js/src/tests/style/BadIncludesOrder-inl.h:8:9: error:
    "ds/LifoAlloc.h" should be included after "jsapi.h"

js/src/tests/style/BadIncludesOrder-inl.h:9:10: error:
    "jsapi.h" should be included after <stdio.h>

js/src/tests/style/BadIncludesOrder-inl.h:10:11: error:
    <stdio.h> should be included after "mozilla/HashFunctions.h"

js/src/tests/style/BadIncludesOrder-inl.h:27:28: error:
    "jsobj.h" should be included after "jsfun.h"

(multiple files): error:
    header files form one or more cycles

   tests/style/HeaderCycleA1.h
   -> tests/style/HeaderCycleA2.h
      -> tests/style/HeaderCycleA3.h
         -> tests/style/HeaderCycleA1.h

   tests/style/HeaderCycleB1-inl.h
   -> tests/style/HeaderCycleB2-inl.h
      -> tests/style/HeaderCycleB3-inl.h
         -> tests/style/HeaderCycleB4-inl.h
            -> tests/style/HeaderCycleB1-inl.h
            -> tests/style/jsheadercycleB5inlines.h
               -> tests/style/HeaderCycleB1-inl.h
      -> tests/style/HeaderCycleB4-inl.h

'''.splitlines(True)

actual_output = []


def out(*lines):
    for line in lines:
        actual_output.append(line + '\n')


def error(filename, linenum, *lines):
    location = filename
    if linenum is not None:
        location += ':' + str(linenum)
    out(location + ': error:')
    for line in (lines):
        out('    ' + line)
    out('')


class FileKind(object):
    C = 1
    CPP = 2
    INL_H = 3
    H = 4
    TBL = 5
    MSG = 6

    @staticmethod
    def get(filename):
        if filename.endswith('.c'):
            return FileKind.C

        if filename.endswith('.cpp'):
            return FileKind.CPP

        if filename.endswith(('inlines.h', '-inl.h')):
            return FileKind.INL_H

        if filename.endswith('.h'):
            return FileKind.H

        if filename.endswith('.tbl'):
            return FileKind.TBL

        if filename.endswith('.msg'):
            return FileKind.MSG

        error(filename, None, 'unknown file kind')


def check_style():
    # We deal with two kinds of name.
    # - A "filename" is a full path to a file from the repository root.
    # - An "inclname" is how a file is referred to in a #include statement.
    #
    # Examples (filename -> inclname)
    # - "mfbt/Attributes.h"         -> "mozilla/Attributes.h"
    # - "mfbt/decimal/Decimal.h     -> "mozilla/Decimal.h"
    # - "mozglue/misc/TimeStamp.h   -> "mozilla/TimeStamp.h"
    # - "memory/mozalloc/mozalloc.h -> "mozilla/mozalloc.h"
    # - "js/public/Vector.h"        -> "js/Vector.h"
    # - "js/src/vm/String.h"        -> "vm/String.h"

    non_js_dirnames = ('mfbt/',
                       'memory/mozalloc/',
                       'mozglue/')  # type: tuple(str)
    non_js_inclnames = set()        # type: set(inclname)
    js_names = dict()               # type: dict(filename, inclname)

    # Select the appropriate files.
    for filename in get_all_toplevel_filenames():
        for non_js_dir in non_js_dirnames:
            if filename.startswith(non_js_dir) and filename.endswith('.h'):
                inclname = 'mozilla/' + filename.split('/')[-1]
                non_js_inclnames.add(inclname)

        if filename.startswith('js/public/') and filename.endswith('.h'):
            inclname = 'js/' + filename[len('js/public/'):]
            js_names[filename] = inclname

        if filename.startswith('js/src/') and \
           not filename.startswith(tuple(ignored_js_src_dirs)) and \
           filename.endswith(('.c', '.cpp', '.h', '.tbl', '.msg')):
            inclname = filename[len('js/src/'):]
            js_names[filename] = inclname

    all_inclnames = non_js_inclnames | set(js_names.values())

    edges = dict()      # type: dict(inclname, set(inclname))

    # We don't care what's inside the MFBT and MOZALLOC files, but because they
    # are #included from JS files we have to add them to the inclusion graph.
    for inclname in non_js_inclnames:
        edges[inclname] = set()

    # Process all the JS files.
    for filename in js_names.keys():
        inclname = js_names[filename]
        file_kind = FileKind.get(filename)
        if file_kind == FileKind.C or file_kind == FileKind.CPP or \
           file_kind == FileKind.H or file_kind == FileKind.INL_H:
            included_h_inclnames = set()    # type: set(inclname)

            # This script is run in js/src/, so prepend '../../' to get to the root of the Mozilla
            # source tree.
            with open(os.path.join('../..', filename)) as f:
                do_file(filename, inclname, file_kind, f, all_inclnames, included_h_inclnames)

        edges[inclname] = included_h_inclnames

    find_cycles(all_inclnames, edges)

    # Compare expected and actual output.
    difflines = difflib.unified_diff(expected_output, actual_output,
                                     fromfile='check_spider_monkey_style.py expected output',
                                       tofile='check_spider_monkey_style.py actual output')
    ok = True
    for diffline in difflines:
        ok = False
        print(diffline, end='')

    return ok


def module_name(name):
    '''Strip the trailing .cpp, .h, inlines.h or -inl.h from a filename.'''

    return name.replace('inlines.h', '').replace('-inl.h', '').replace('.h', '').replace('.cpp', '')


def is_module_header(enclosing_inclname, header_inclname):
    '''Determine if an included name is the "module header", i.e. should be
    first in the file.'''

    module = module_name(enclosing_inclname)

    # Normal case, e.g. module == "foo/Bar", header_inclname == "foo/Bar.h".
    if module == module_name(header_inclname):
        return True

    # A public header, e.g. module == "foo/Bar", header_inclname == "js/Bar.h".
    m = re.match(r'js\/(.*)\.h', header_inclname)
    if m is not None and module.endswith('/' + m.group(1)):
        return True

    return False


class Include(object):
    '''Important information for a single #include statement.'''

    def __init__(self, inclname, linenum, is_system):
        self.inclname = inclname
        self.linenum = linenum
        self.is_system = is_system

    def isLeaf(self):
        return True

    def section(self, enclosing_inclname):
        '''Identify which section inclname belongs to.

        The section numbers are as follows.
          0. Module header (e.g. jsfoo.h or jsfooinlines.h within jsfoo.cpp)
          1. mozilla/Foo.h
          2. <foo.h> or <foo>
          3. jsfoo.h, prmjtime.h, etc
          4. foo/Bar.h
          5. jsfooinlines.h
          6. foo/Bar-inl.h
          7. non-.h, e.g. *.tbl, *.msg
        '''

        if self.is_system:
            return 2

        if not self.inclname.endswith('.h'):
            return 7

        # A couple of modules have the .h file in js/ and the .cpp file elsewhere and so need
        # special handling.
        if is_module_header(enclosing_inclname, self.inclname):
            return 0

        if '/' in self.inclname:
            if self.inclname.startswith('mozilla/'):
                return 1

            if self.inclname.endswith('-inl.h'):
                return 6

            return 4

        if self.inclname.endswith('inlines.h'):
            return 5

        return 3

    def quote(self):
        if self.is_system:
            return '<' + self.inclname + '>'
        else:
            return '"' + self.inclname + '"'


class HashIfBlock(object):
    '''Important information about a #if/#endif block.

    A #if/#endif block is the contents of a #if/#endif (or similar) section.
    The top-level block, which is not within a #if/#endif pair, is also
    considered a block.

    Each leaf is either an Include (representing a #include), or another
    nested HashIfBlock.'''
    def __init__(self):
        self.kids = []

    def isLeaf(self):
        return False


def do_file(filename, inclname, file_kind, f, all_inclnames, included_h_inclnames):
    block_stack = [HashIfBlock()]

    # Extract the #include statements as a tree of IBlocks and IIncludes.
    for linenum, line in enumerate(f, start=1):
        # We're only interested in lines that contain a '#'.
        if not '#' in line:
            continue

        # Look for a |#include "..."| line.
        m = re.match(r'\s*#\s*include\s+"([^"]*)"', line)
        if m is not None:
            block_stack[-1].kids.append(Include(m.group(1), linenum, False))

        # Look for a |#include <...>| line.
        m = re.match(r'\s*#\s*include\s+<([^>]*)>', line)
        if m is not None:
            block_stack[-1].kids.append(Include(m.group(1), linenum, True))

        # Look for a |#{if,ifdef,ifndef}| line.
        m = re.match(r'\s*#\s*(if|ifdef|ifndef)\b', line)
        if m is not None:
            # Open a new block.
            new_block = HashIfBlock()
            block_stack[-1].kids.append(new_block)
            block_stack.append(new_block)

        # Look for a |#{elif,else}| line.
        m = re.match(r'\s*#\s*(elif|else)\b', line)
        if m is not None:
            # Close the current block, and open an adjacent one.
            block_stack.pop()
            new_block = HashIfBlock()
            block_stack[-1].kids.append(new_block)
            block_stack.append(new_block)

        # Look for a |#endif| line.
        m = re.match(r'\s*#\s*endif\b', line)
        if m is not None:
            # Close the current block.
            block_stack.pop()

    def check_include_statement(include):
        '''Check the style of a single #include statement.'''

        if include.is_system:
            # Check it is not a known local file (in which case it's probably a system header).
            if include.inclname in included_inclnames_to_ignore or \
               include.inclname in all_inclnames:
                error(filename, include.linenum,
                      include.quote() + ' should be included using',
                      'the #include "..." form')

        else:
            if include.inclname not in included_inclnames_to_ignore:
                included_kind = FileKind.get(include.inclname)

                # Check the #include path has the correct form.
                if include.inclname not in all_inclnames:
                    error(filename, include.linenum,
                          include.quote() + ' is included using the wrong path;',
                          'did you forget a prefix, or is the file not yet committed?')

                # Record inclusions of .h files for cycle detection later.
                # (Exclude .tbl and .msg files.)
                elif included_kind == FileKind.H or included_kind == FileKind.INL_H:
                    included_h_inclnames.add(include.inclname)

                # Check a H file doesn't #include an INL_H file.
                if file_kind == FileKind.H and included_kind == FileKind.INL_H:
                    error(filename, include.linenum,
                          'vanilla header includes an inline-header file ' + include.quote())

                # Check a file doesn't #include itself.  (We do this here because the cycle
                # detection below doesn't detect this case.)
                if inclname == include.inclname:
                    error(filename, include.linenum, 'the file includes itself')

    def check_includes_order(include1, include2):
        '''Check the ordering of two #include statements.'''

        if include1.inclname in oddly_ordered_inclnames or \
           include2.inclname in oddly_ordered_inclnames:
            return

        section1 = include1.section(inclname)
        section2 = include2.section(inclname)
        if (section1 > section2) or \
           ((section1 == section2) and (include1.inclname.lower() > include2.inclname.lower())):
            error(filename, str(include1.linenum) + ':' + str(include2.linenum),
                  include1.quote() + ' should be included after ' + include2.quote())

    # Check the extracted #include statements, both individually, and the ordering of
    # adjacent pairs that live in the same block.
    def pair_traverse(prev, this):
        if this.isLeaf():
            check_include_statement(this)
            if prev is not None and prev.isLeaf():
                check_includes_order(prev, this)
        else:
            for prev2, this2 in zip([None] + this.kids[0:-1], this.kids):
                pair_traverse(prev2, this2)

    pair_traverse(None, block_stack[-1])


def find_cycles(all_inclnames, edges):
    '''Find and draw any cycles.'''

    SCCs = tarjan(all_inclnames, edges)

    # The various sorted() calls below ensure the output is deterministic.

    def draw_SCC(c):
        cset = set(c)
        drawn = set()
        def draw(v, indent):
            out('   ' * indent + ('-> ' if indent else '   ') + v)
            if v in drawn:
                return
            drawn.add(v)
            for succ in sorted(edges[v]):
                if succ in cset:
                    draw(succ, indent + 1)
        draw(sorted(c)[0], 0)
        out('')

    have_drawn_an_SCC = False
    for scc in sorted(SCCs):
        if len(scc) != 1:
            if not have_drawn_an_SCC:
                error('(multiple files)', None, 'header files form one or more cycles')
                have_drawn_an_SCC = True

            draw_SCC(scc)


# Tarjan's algorithm for finding the strongly connected components (SCCs) of a graph.
# https://en.wikipedia.org/wiki/Tarjan%27s_strongly_connected_components_algorithm
def tarjan(V, E):
    vertex_index = {}
    vertex_lowlink = {}
    index = 0
    S = []
    all_SCCs = []

    def strongconnect(v, index):
        # Set the depth index for v to the smallest unused index
        vertex_index[v] = index
        vertex_lowlink[v] = index
        index += 1
        S.append(v)

        # Consider successors of v
        for w in E[v]:
            if w not in vertex_index:
                # Successor w has not yet been visited; recurse on it
                index = strongconnect(w, index)
                vertex_lowlink[v] = min(vertex_lowlink[v], vertex_lowlink[w])
            elif w in S:
                # Successor w is in stack S and hence in the current SCC
                vertex_lowlink[v] = min(vertex_lowlink[v], vertex_index[w])

        # If v is a root node, pop the stack and generate an SCC
        if vertex_lowlink[v] == vertex_index[v]:
            i = S.index(v)
            scc = S[i:]
            del S[i:]
            all_SCCs.append(scc)

        return index

    for v in V:
        if v not in vertex_index:
            index = strongconnect(v, index)

    return all_SCCs


def main():
    ok = check_style()

    if ok:
        print('TEST-PASS | check_spidermonkey_style.py | ok')
    else:
        print('TEST-UNEXPECTED-FAIL | check_spidermonkey_style.py | actual output does not match expected output;  diff is above')

    sys.exit(0 if ok else 1)


if __name__ == '__main__':
    main()