Backed out changeset 1f0cfca78242 (bug 1619460) perf regression in automation, req by rstewart. CLOSED TREE

--HG-- extra : rebase_source : ef3f1ce03bc9fdedb81d33ede68f9925f447ba32
2020-03-12 19:37:27 +02:00 · 2020-03-12 19:37:27 +02:00 · 4437350f38
--- a/build/moz.build
+++ b/build/moz.build
@ -91,7 +91,7 @@ if CONFIG['MOZ_APP_BASENAME']:
        entry_point='generate',
        inputs=['application.ini.in'],
        flags=['-D%s=%s' % (k, '1' if v is True else v)
-               for k, v in sorted(appini_defines.items(), key=lambda t: t[0])])
+               for k, v in appini_defines.items()])
    
    FINAL_TARGET_FILES += ['!application.ini']
    if CONFIG['MOZ_WIDGET_TOOLKIT'] != 'android' and CONFIG['MOZ_UPDATER']:
--- a/config/external/ffi/moz.build
+++ b/config/external/ffi/moz.build
@ -26,12 +26,14 @@ else:
        '/js/src/ctypes/libffi/src/%s' % CONFIG['FFI_TARGET_DIR'],
    ]

-    DEFINES['TARGET'] = CONFIG['FFI_TARGET']
-    DEFINES[CONFIG['FFI_TARGET']] = True
-    DEFINES['FFI_NO_RAW_API'] = True
-    DEFINES['HAVE_AS_ASCII_PSEUDO_OP'] = True
-    DEFINES['HAVE_AS_STRING_PSEUDO_OP'] = True
-    DEFINES['HAVE_AS_X86_64_UNWIND_SECTION_TYPE'] = True
+    DEFINES.update({
+        'TARGET': CONFIG['FFI_TARGET'],
+        CONFIG['FFI_TARGET']: True,
+        'FFI_NO_RAW_API': True,
+        'HAVE_AS_ASCII_PSEUDO_OP': True,
+        'HAVE_AS_STRING_PSEUDO_OP': True,
+        'HAVE_AS_X86_64_UNWIND_SECTION_TYPE': True,
+    })

    if CONFIG['MOZ_DEBUG']:
        DEFINES['FFI_DEBUG'] = True
--- a/config/external/icu/defs.mozbuild
+++ b/config/external/icu/defs.mozbuild
@ -6,23 +6,26 @@

 # Also see <http://www.icu-project.org/repos/icu/tags/latest/icu4c/readme.html#RecBuild> for the
 # recommended build options when compiling ICU.
-# Don't use icu namespace automatically in client code.
-DEFINES['U_USING_ICU_NAMESPACE'] = 0
-# Don't include obsolete header files.
-DEFINES['U_NO_DEFAULT_INCLUDE_UTF_HEADERS'] = 1
-DEFINES['U_HIDE_OBSOLETE_UTF_OLD_H'] = 1
+DEFINES.update(
+    # Don't use icu namespace automatically in client code.
+    U_USING_ICU_NAMESPACE = 0,

-# Remove chunks of the library that we don't need (yet).
-DEFINES['UCONFIG_NO_LEGACY_CONVERSION'] = True
-DEFINES['UCONFIG_NO_TRANSLITERATION'] = True
-DEFINES['UCONFIG_NO_REGULAR_EXPRESSIONS'] = True
+    # Don't include obsolete header files.
+    U_NO_DEFAULT_INCLUDE_UTF_HEADERS = 1,
+    U_HIDE_OBSOLETE_UTF_OLD_H = 1,

-# We don't need to pass data to and from legacy char* APIs.
-DEFINES['U_CHARSET_IS_UTF8'] = True
+    # Remove chunks of the library that we don't need (yet).
+    UCONFIG_NO_LEGACY_CONVERSION = True,
+    UCONFIG_NO_TRANSLITERATION = True,
+    UCONFIG_NO_REGULAR_EXPRESSIONS = True,

-# Add 'explicit' keyword to UnicodeString constructors.
-DEFINES['UNISTR_FROM_CHAR_EXPLICIT'] = "explicit"
-DEFINES['UNISTR_FROM_STRING_EXPLICIT'] = "explicit"
+    # We don't need to pass data to and from legacy char* APIs.
+    U_CHARSET_IS_UTF8 = True,
+
+    # Add 'explicit' keyword to UnicodeString constructors.
+    UNISTR_FROM_CHAR_EXPLICIT = "explicit",
+    UNISTR_FROM_STRING_EXPLICIT = "explicit",
+)

 if not CONFIG['HAVE_LANGINFO_CODESET']:
    DEFINES['U_HAVE_NL_LANGINFO_CODESET'] = 0
--- a/config/external/nspr/pr/moz.build
+++ b/config/external/nspr/pr/moz.build
@ -16,10 +16,12 @@ AllowCompilerWarnings()
 DEFINES['_NSPR_BUILD_'] = True
 if CONFIG['OS_ARCH'] == 'Linux':
    OS_LIBS += CONFIG['REALTIME_LIBS']
-    DEFINES['LINUX'] = True
-    DEFINES['HAVE_FCNTL_FILE_LOCKING'] = True
-    DEFINES['HAVE_POINTER_LOCALTIME_R'] = True
-    DEFINES['_GNU_SOURCE'] = True
+    DEFINES.update(
+        LINUX=True,
+        HAVE_FCNTL_FILE_LOCKING=True,
+        HAVE_POINTER_LOCALTIME_R=True,
+        _GNU_SOURCE=True,
+    )
    SOURCES += ['/nsprpub/pr/src/md/unix/linux.c']
    if CONFIG['CPU_ARCH'] == 'x86_64':
        SOURCES += ['/nsprpub/pr/src/md/unix/os_Linux_x86_64.s']
@ -29,9 +31,11 @@ if CONFIG['OS_ARCH'] == 'Linux':
    elif CONFIG['CPU_ARCH'] == 'ppc':
        SOURCES += ['/nsprpub/pr/src/md/unix/os_Linux_ppc.s']
 elif CONFIG['OS_TARGET'] in ('FreeBSD', 'OpenBSD', 'NetBSD'):
-    DEFINES['HAVE_BSD_FLOCK'] = True
-    DEFINES['HAVE_SOCKLEN_T'] = True
-    DEFINES['HAVE_POINTER_LOCALTIME_R'] = True
+    DEFINES.update(
+        HAVE_BSD_FLOCK=True,
+        HAVE_SOCKLEN_T=True,
+        HAVE_POINTER_LOCALTIME_R=True,
+    )
    DEFINES[CONFIG['OS_TARGET'].upper()] = True
    SOURCES += ['/nsprpub/pr/src/md/unix/%s.c' % CONFIG['OS_TARGET'].lower()]
 elif CONFIG['OS_TARGET'] == 'Darwin':
@ -40,13 +44,19 @@ elif CONFIG['OS_TARGET'] == 'Darwin':
    DEFINES['FD_SETSIZE'] = 4096
    DEFINES['_DARWIN_UNLIMITED_SELECT'] = True
    if not CONFIG['HOST_MAJOR_VERSION']:
-        DEFINES['HAS_CONNECTX'] = True
+        DEFINES.update(
+            HAS_CONNECTX=True,
+        )
    elif CONFIG['HOST_MAJOR_VERSION'] >= '15':
-        DEFINES['HAS_CONNECTX'] = True
-    DEFINES['DARWIN'] = True
-    DEFINES['HAVE_BSD_FLOCK'] = True
-    DEFINES['HAVE_SOCKLEN_T'] = True
-    DEFINES['HAVE_POINTER_LOCALTIME_R'] = True
+        DEFINES.update(
+            HAS_CONNECTX=True,
+        )
+    DEFINES.update(
+        DARWIN=True,
+        HAVE_BSD_FLOCK=True,
+        HAVE_SOCKLEN_T=True,
+        HAVE_POINTER_LOCALTIME_R=True,
+    )
    SOURCES += [
        '/nsprpub/pr/src/md/unix/darwin.c',
        '/nsprpub/pr/src/md/unix/os_Darwin.s',
@ -54,10 +64,12 @@ elif CONFIG['OS_TARGET'] == 'Darwin':
    if not CONFIG['MOZ_IOS']:
        DEFINES['HAVE_CRT_EXTERNS_H'] = True
 elif CONFIG['OS_TARGET'] == 'SunOS':
-    DEFINES['HAVE_FCNTL_FILE_LOCKING'] = True
-    DEFINES['HAVE_SOCKLEN_T'] = True
-    DEFINES['_PR_HAVE_OFF64_T'] = True
-    DEFINES['_PR_INET6'] = True
+    DEFINES.update(
+        HAVE_FCNTL_FILE_LOCKING=True,
+        HAVE_SOCKLEN_T=True,
+        _PR_HAVE_OFF64_T=True,
+        _PR_INET6=True,
+    )
    DEFINES['SOLARIS'] = True
    SOURCES += ['/nsprpub/pr/src/md/unix/solaris.c']
    if CONFIG['CPU_ARCH'] == 'x86_64':
@ -74,13 +86,15 @@ elif CONFIG['OS_TARGET'] == 'WINNT':
        'mswsock',
        'winmm',
    ]
-    DEFINES['XP_PC'] = True
-    DEFINES['WIN32'] = True
+    DEFINES.update(
+        XP_PC=True,
+        WIN32=True,
        # For historical reasons we use the WIN95 NSPR target instead of
        # WINNT.
-    DEFINES['WIN95'] = True
-    DEFINES['WINNT'] = False
-    DEFINES['_PR_GLOBAL_THREADS_ONLY'] = True
+        WIN95=True,
+        WINNT=False,
+        _PR_GLOBAL_THREADS_ONLY=True,
+    )
    if not CONFIG['DEBUG']:
      DEFINES['DO_NOT_WAIT_FOR_CONNECT_OVERLAPPED_OPERATIONS'] = True
    if CONFIG['CPU_ARCH'] == 'x86_64':
--- a/config/moz.build
+++ b/config/moz.build
@ -33,8 +33,10 @@ PYTHON_UNITTEST_MANIFESTS += [
 if CONFIG['CC_TYPE'] in ('clang', 'gcc') and CONFIG['MOZ_OPTIMIZE']:
    CFLAGS += ['-O3']

-HOST_DEFINES['UNICODE'] = True
-HOST_DEFINES['_UNICODE'] = True
+HOST_DEFINES = {
+    'UNICODE': True,
+    '_UNICODE': True,
+}

 include('stl-headers.mozbuild')
 if CONFIG['WRAP_STL_INCLUDES']:
--- a/dom/bindings/test/moz.build
+++ b/dom/bindings/test/moz.build
@ -4,8 +4,10 @@
 # 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/.

-DEFINES['IMPL_LIBXUL'] = True
-DEFINES['MOZILLA_INTERNAL_API'] = True
+DEFINES.update({
+    'IMPL_LIBXUL': True,
+    'MOZILLA_INTERNAL_API': True,
+})

 # Do NOT export this library.  We don't actually want our test code
 # being added to libxul or anything.
--- a/ipc/chromium/chromium-config.mozbuild
+++ b/ipc/chromium/chromium-config.mozbuild
@ -16,18 +16,20 @@ if CONFIG['OS_ARCH'] == 'WINNT':
        'dbghelp',
    ]

-    DEFINES['UNICODE'] = True
-    DEFINES['_UNICODE'] = True
-    DEFINES['_CRT_RAND_S'] = True
-    DEFINES['CERT_CHAIN_PARA_HAS_EXTRA_FIELDS'] = True
-    DEFINES['_SECURE_ATL'] = True
-    DEFINES['CHROMIUM_BUILD'] = True
-    DEFINES['U_STATIC_IMPLEMENTATION'] = True
-    DEFINES['OS_WIN'] = 1
-    DEFINES['WIN32'] = True
-    DEFINES['_WIN32'] = True
-    DEFINES['_WINDOWS'] = True
-    DEFINES['WIN32_LEAN_AND_MEAN'] = True
+    DEFINES.update({
+        'UNICODE': True,
+        '_UNICODE': True,
+        '_CRT_RAND_S': True,
+        'CERT_CHAIN_PARA_HAS_EXTRA_FIELDS': True,
+        '_SECURE_ATL': True,
+        'CHROMIUM_BUILD': True,
+        'U_STATIC_IMPLEMENTATION': True,
+        'OS_WIN': 1,
+        'WIN32': True,
+        '_WIN32': True,
+        '_WINDOWS': True,
+        'WIN32_LEAN_AND_MEAN': True,
+    })

    if CONFIG['CC_TYPE'] == 'clang-cl':
        DEFINES['COMPILER_MSVC'] = True
@ -42,20 +44,28 @@ else:
        DEFINES['OS_SOLARIS'] = 1

    elif CONFIG['OS_ARCH'] == 'DragonFly':
-        DEFINES['OS_DRAGONFLY'] = 1
-        DEFINES['OS_BSD'] = 1
+        DEFINES.update({
+            'OS_DRAGONFLY': 1,
+            'OS_BSD': 1,
+        })

    elif CONFIG['OS_ARCH'] == 'FreeBSD' or CONFIG['OS_ARCH'] == 'GNU_kFreeBSD':
-        DEFINES['OS_FREEBSD'] = 1
-        DEFINES['OS_BSD'] = 1
+        DEFINES.update({
+            'OS_FREEBSD': 1,
+            'OS_BSD': 1,
+        })

    elif CONFIG['OS_ARCH'] == 'NetBSD':
-        DEFINES['OS_NETBSD'] = 1
-        DEFINES['OS_BSD'] = 1
+        DEFINES.update({
+            'OS_NETBSD': 1,
+            'OS_BSD': 1,
+        })

    elif CONFIG['OS_ARCH'] == 'OpenBSD':
-        DEFINES['OS_OPENBSD'] = 1
-        DEFINES['OS_BSD'] = 1
+        DEFINES.update({
+            'OS_OPENBSD': 1,
+            'OS_BSD': 1,
+        })

    else:
        DEFINES['OS_LINUX'] = 1
--- a/netwerk/protocol/http/moz.build
+++ b/netwerk/protocol/http/moz.build
@ -169,8 +169,12 @@ XPCOM_MANIFESTS += [

 if CONFIG['OS_TARGET'] == 'Darwin':
    if not CONFIG['HOST_MAJOR_VERSION']:
-        DEFINES['HAS_CONNECTX'] = True
+        DEFINES.update(
+            HAS_CONNECTX=True,
+        )
    elif CONFIG['HOST_MAJOR_VERSION'] >= '15':
-        DEFINES['HAS_CONNECTX'] = True
+        DEFINES.update(
+            HAS_CONNECTX=True,
+        )

 include('/tools/fuzzing/libfuzzer-config.mozbuild')
--- a/python/mozbuild/mozbuild/backend/fastermake.py
+++ b/python/mozbuild/mozbuild/backend/fastermake.py
@ -4,7 +4,6 @@

 from __future__ import absolute_import, unicode_literals, print_function

-from operator import itemgetter
 import six

 from mozbuild.backend.base import PartialBackend
@ -195,12 +194,12 @@ class FasterMakeBackend(MakeBackend, PartialBackend):

        # Add information for install manifests.
        mk.add_statement('INSTALL_MANIFESTS = %s'
-                         % ' '.join(sorted(self._install_manifests.keys())))
+                         % ' '.join(self._install_manifests.keys()))

        # Add dependencies we inferred:
-        for target, deps in sorted(six.iteritems(self._dependencies)):
+        for target, deps in six.iteritems(self._dependencies):
            mk.create_rule([target]).add_dependencies(
-                '$(TOPOBJDIR)/%s' % d for d in sorted(deps))
+                '$(TOPOBJDIR)/%s' % d for d in deps)

        # This is not great, but it's better to have some dependencies on these Python files.
        python_deps = [
@ -209,9 +208,9 @@ class FasterMakeBackend(MakeBackend, PartialBackend):
            '$(TOPSRCDIR)/third_party/python/compare-locales/compare_locales/paths.py',
        ]
        # Add l10n dependencies we inferred:
-        for target, deps in sorted(six.iteritems(self._l10n_dependencies)):
+        for target, deps in six.iteritems(self._l10n_dependencies):
            mk.create_rule([target]).add_dependencies(
-                '%s' % d[0] for d in sorted(deps, key=itemgetter(0)))
+                '%s' % d[0] for d in deps)
            for (merge, ref_file, l10n_file) in deps:
                rule = mk.create_rule([merge]).add_dependencies(
                    [ref_file, l10n_file] + python_deps)
--- a/python/mozbuild/mozbuild/backend/recursivemake.py
+++ b/python/mozbuild/mozbuild/backend/recursivemake.py
@ -14,9 +14,8 @@ from collections import (
    defaultdict,
    namedtuple,
 )
-from itertools import chain
-from operator import itemgetter
 from six import StringIO
+from itertools import chain

 from mozpack.manifests import (
    InstallManifest,
@ -746,21 +745,20 @@ class RecursiveMakeBackend(MakeBackend):
        root_deps_mk = Makefile()

        # Fill the dependencies for traversal of each tier.
-        for tier, filter in sorted(filters, key=itemgetter(0)):
+        for tier, filter in filters:
            main, all_deps = \
                self._traversal.compute_dependencies(filter)
-            for dir, deps in sorted(all_deps.items()):
+            for dir, deps in all_deps.items():
                if deps is not None or (dir in self._idl_dirs
                                        and tier == 'export'):
                    rule = root_deps_mk.create_rule(['%s/%s' % (dir, tier)])
                if deps:
-                        rule.add_dependencies(
-                            '%s/%s' % (d, tier) for d in sorted(deps) if d)
+                    rule.add_dependencies('%s/%s' % (d, tier) for d in deps if d)
                if dir in self._idl_dirs and tier == 'export':
                    rule.add_dependencies(['xpcom/xpidl/%s' % tier])
            rule = root_deps_mk.create_rule(['recurse_%s' % tier])
            if main:
-                rule.add_dependencies('%s/%s' % (d, tier) for d in sorted(main))
+                rule.add_dependencies('%s/%s' % (d, tier) for d in main)

        all_compile_deps = six.moves.reduce(
            lambda x, y: x | y,
@ -785,8 +783,8 @@ class RecursiveMakeBackend(MakeBackend):
            # Directories containing rust compilations don't generally depend
            # on other directories in the tree, so putting them first here will
            # start them earlier in the build.
-            rust_roots = sorted(r for r in roots if r in self._rust_targets)
-            rust_libs = sorted(r for r in roots if r in self._rust_lib_targets)
+            rust_roots = [r for r in roots if r in self._rust_targets]
+            rust_libs = [r for r in roots if r in self._rust_lib_targets]
            if category == 'compile' and rust_roots:
                rust_rule = root_deps_mk.create_rule(['recurse_rust'])
                rust_rule.add_dependencies(rust_roots)
@ -802,11 +800,11 @@ class RecursiveMakeBackend(MakeBackend):
                    r = root_deps_mk.create_rule([target])
                    r.add_dependencies([prior_target])

-            rule.add_dependencies(sorted(chain(rust_roots, roots)))
+            rule.add_dependencies(chain(rust_roots, roots))
            for target, deps in sorted(graph.items()):
                if deps:
                    rule = root_deps_mk.create_rule([target])
-                    rule.add_dependencies(sorted(deps))
+                    rule.add_dependencies(deps)

        non_default_roots = defaultdict(list)
        non_default_graphs = defaultdict(lambda: OrderedDefaultDict(set))
@ -832,7 +830,7 @@ class RecursiveMakeBackend(MakeBackend):
                self._no_skip['syms'].remove(dirname)

        add_category_rules('compile', compile_roots, self._compile_graph)
-        for category, graph in sorted(six.iteritems(non_default_graphs)):
+        for category, graph in six.iteritems(non_default_graphs):
            add_category_rules(category, non_default_roots[category], graph)

        root_mk = Makefile()
@ -854,7 +852,7 @@ class RecursiveMakeBackend(MakeBackend):
        root_mk.add_statement('non_default_tiers := %s' % ' '.join(sorted(
            non_default_roots.keys())))

-        for category, graphs in sorted(six.iteritems(non_default_graphs)):
+        for category, graphs in six.iteritems(non_default_graphs):
            category_dirs = [mozpath.dirname(target)
                             for target in graphs.keys()]
            root_mk.add_statement('%s_dirs := %s' % (category,
--- a/python/mozbuild/mozbuild/frontend/context.py
+++ b/python/mozbuild/mozbuild/frontend/context.py
@ -305,26 +305,8 @@ class InitializedDefines(ContextDerivedValue, OrderedDict):
        for define in context.config.substs.get('MOZ_DEBUG_DEFINES', ()):
            self[define] = 1
        if value:
-            if not isinstance(value, OrderedDict):
-                raise ValueError('Can only initialize with another OrderedDict')
            self.update(value)

-    def update(self, *other, **kwargs):
-        # Since iteration over non-ordered dicts is non-deterministic, this dict
-        # will be populated in an unpredictable order unless the argument to
-        # update() is also ordered. (It's important that we maintain this
-        # invariant so we can be sure that running `./mach build-backend` twice
-        # in a row without updating any files in the workspace generates exactly
-        # the same output.)
-        if kwargs:
-            raise ValueError('Cannot call update() with kwargs')
-        if other:
-            if not isinstance(other[0], OrderedDict):
-                raise ValueError(
-                    'Can only call update() with another OrderedDict')
-            return super(InitializedDefines, self).update(*other, **kwargs)
-        raise ValueError('No arguments passed to update()')
-

 class BaseCompileFlags(ContextDerivedValue, dict):
    def __init__(self, context):
@ -1492,7 +1474,14 @@ VARIABLES = {

        This will result in the compiler flags ``-DNS_NO_XPCOM``,
        ``-DMOZ_EXTENSIONS_DB_SCHEMA=15``, and ``-DDLL_SUFFIX='".so"'``,
-        respectively.
+        respectively. These could also be combined into a single
+        update::
+
+           DEFINES.update({
+               'NS_NO_XPCOM': True,
+               'MOZ_EXTENSIONS_DB_SCHEMA': 15,
+               'DLL_SUFFIX': '".so"',
+           })
        """
        ),

--- a/python/mozbuild/mozbuild/frontend/data.py
+++ b/python/mozbuild/mozbuild/frontend/data.py
@ -190,7 +190,7 @@ class ComputedFlags(ContextDerived):
            if value:
                for dest_var in dest_vars:
                    flags[dest_var].extend(value)
-        return sorted(flags.items())
+        return flags.items()


 class XPIDLModule(ContextDerived):
--- a/python/mozbuild/mozbuild/test/backend/data/defines/moz.build
+++ b/python/mozbuild/mozbuild/test/backend/data/defines/moz.build
@ -2,7 +2,10 @@
 # http://creativecommons.org/publicdomain/zero/1.0/

 value = 'xyz'
-DEFINES['FOO'] = True
+DEFINES = {
+    'FOO': True,
+}
+
 DEFINES['BAZ'] = '"ab\'cd"'
 DEFINES['QUX'] = False
 DEFINES['BAR'] = 7
--- a/python/mozbuild/mozbuild/test/backend/data/host-defines/moz.build
+++ b/python/mozbuild/mozbuild/test/backend/data/host-defines/moz.build
@ -2,8 +2,13 @@
 # http://creativecommons.org/publicdomain/zero/1.0/

 value = 'xyz'
-HOST_DEFINES['FOO'] = True
+HOST_DEFINES = {
+    'FOO': True,
+}
+
 HOST_DEFINES['BAZ'] = '"ab\'cd"'
-HOST_DEFINES['BAR'] = 7
-HOST_DEFINES['VALUE'] = value
-HOST_DEFINES['QUX'] = False
+HOST_DEFINES.update({
+    'BAR': 7,
+    'VALUE': value,
+    'QUX': False,
+})
--- a/python/mozbuild/mozbuild/test/backend/test_recursivemake.py
+++ b/python/mozbuild/mozbuild/test/backend/test_recursivemake.py
@ -931,7 +931,7 @@ class TestRecursiveMakeBackend(BackendTester):
        root_deps_path = mozpath.join(env.topobjdir, 'root-deps.mk')
        lines = [l.strip() for l in open(root_deps_path, 'rt').readlines()]

-        self.assertTrue(any(l == 'recurse_compile: code/host code/target' for l in lines))
+        self.assertTrue(any(l == 'recurse_compile: code/target code/host' for l in lines))

    def test_final_target(self):
        """Test that FINAL_TARGET is written to backend.mk correctly."""
--- a/python/mozbuild/mozbuild/test/frontend/data/defines/moz.build
+++ b/python/mozbuild/mozbuild/test/frontend/data/defines/moz.build
@ -2,8 +2,13 @@
 # http://creativecommons.org/publicdomain/zero/1.0/

 value = 'xyz'
-DEFINES['FOO'] = True
+DEFINES = {
+    'FOO': True,
+}
+
 DEFINES['BAZ'] = '"abcd"'
-DEFINES['BAR'] = 7
-DEFINES['VALUE'] = value
-DEFINES['QUX'] = False
+DEFINES.update({
+    'BAR': 7,
+    'VALUE': value,
+    'QUX': False,
+})
--- a/python/mozbuild/mozbuild/test/frontend/data/host-compile-flags/moz.build
+++ b/python/mozbuild/mozbuild/test/frontend/data/host-compile-flags/moz.build
@ -11,10 +11,15 @@ HostLibrary('dummy')
 HOST_SOURCES += ['test1.c']

 value = 'xyz'
-HOST_DEFINES['FOO'] = True
+HOST_DEFINES = {
+    'FOO': True,
+}
+
 HOST_DEFINES['BAZ'] = '"abcd"'
-HOST_DEFINES['BAR'] = 7
-HOST_DEFINES['VALUE'] = value
-HOST_DEFINES['QUX'] = False
+HOST_DEFINES.update({
+    'BAR': 7,
+    'VALUE': value,
+    'QUX': False,
+})

 HOST_CFLAGS += ['-funroll-loops', '-host-arg']
--- a/python/mozbuild/mozbuild/test/frontend/data/wasm-compile-flags/moz.build
+++ b/python/mozbuild/mozbuild/test/frontend/data/wasm-compile-flags/moz.build
@ -6,9 +6,15 @@ SANDBOXED_WASM_LIBRARY_NAME = 'dummy'
 WASM_SOURCES += ['test1.c']

 value = 'xyz'
-WASM_DEFINES['FOO'] = True
+WASM_DEFINES = {
+    'FOO': True,
+}
+
 WASM_DEFINES['BAZ'] = '"abcd"'
-WASM_DEFINES['BAR'] = 7
-WASM_DEFINES['VALUE'] = value
-WASM_DEFINES['QUX'] = False
+WASM_DEFINES.update({
+    'BAR': 7,
+    'VALUE': value,
+    'QUX': False,
+})
+
 WASM_CFLAGS += ['-funroll-loops', '-wasm-arg']
--- a/python/mozbuild/mozbuild/util.py
+++ b/python/mozbuild/mozbuild/util.py
@ -250,9 +250,16 @@ class FileAvoidWrite(BytesIO):
        underlying file was changed, ``.diff`` will be populated with the diff
        of the result.
        """
-        # Use binary data if the caller explicitly asked for it.
-        ensure = six.ensure_binary if self._binary_mode else six.ensure_text
-        buf = ensure(self.getvalue())
+        if self._binary_mode or six.PY2:
+            # Use binary data under Python 2 because it can be written to files
+            # opened with either open(mode='w') or open(mode='wb') without raising
+            # unicode errors. Also use binary data if the caller explicitly asked for
+            # it.
+            buf = self.getvalue()
+        else:
+            # Use strings in Python 3 unless the caller explicitly asked for binary
+            # data.
+            buf = self.getvalue().decode('utf-8')

        BytesIO.close(self)
        existed = False