Issue #2165 - Build ICU as a shared library if we're building Spidermonkey shared.

It seems that if we're going to enable JS_SHARED_LIBRARY, we need ICU to be a
shared library too in order to prevent code duplication in mozjs.dll bloating
it to a whopping 21 MB.
This unfortunately means we have to fold icudata back to icu itself. But since
icudata is still separated from libxul (which is what really matters for #1451),
I think this is a fair compromise.
Building ICU as shared is offered as an option via --enable-shared-icu. But
technically you really need --enable-shared-icu if you're going to use
--enable-shared-js. Unfortunately I can't make configure exit with an error if
MOZ_SHARED_ICU is not defined when JS_SHARED_LIBRARY is enabled, because options
are controlled by different configure scripts (icu is based on bash, while js is
based on python), and I have no idea how to pass MOZ_SHARED_ICU to js's
moz.configure.

Tag #62

build/autoconf/icu.m4

@@ -34,11 +34,10 @@ if test -n "$USE_ICU"; then
     ICU_DATA_FILE="icudt${version}l.dat"
 
     dnl We won't build ICU data as a separate file when building
-    dnl JS standalone so that embedders don't have to deal with it.
-    dnl We also don't do it on Windows because sometimes the file goes
-    dnl missing -- possibly due to overzealous antivirus software? --
-    dnl which prevents the browser from starting up :(
-    if test -z "$JS_STANDALONE"; then
+    dnl ICU as a shared library, as we need to fold the data into
+    dnl the shared library in order for consumers like Spidermonkey
+    dnl to use it without code duplication.
+    if test -z "$MOZ_SHARED_ICU"; then
         MOZ_ICU_DATA_ARCHIVE=1
     else
         MOZ_ICU_DATA_ARCHIVE=
@@ -50,13 +49,15 @@ AC_SUBST(ENABLE_INTL_API)
 AC_SUBST(USE_ICU)
 AC_SUBST(ICU_DATA_FILE)
 AC_SUBST(MOZ_ICU_DATA_ARCHIVE)
+AC_SUBST(MOZ_SHARED_ICU)
 
 if test -n "$USE_ICU"; then
     if test -z "$YASM" -a -z "$GNU_AS" -a "$COMPILE_ENVIRONMENT"; then
       AC_MSG_ERROR([Building ICU requires either yasm or a GNU assembler. If you do not have either of those available for this platform you must use --without-intl-api])
     fi
-    dnl We build ICU as a static library.
+    if test -z "$MOZ_SHARED_ICU"; then
        AC_DEFINE(U_STATIC_IMPLEMENTATION)
+    fi
     dnl Source files that use ICU should have control over which parts of the ICU
     dnl namespace they want to use.
     AC_DEFINE(U_USING_ICU_NAMESPACE,0)

build/moz.configure/old.configure

@@ -226,6 +226,7 @@ def old_configure_options(*options):
     '--enable-safe-browsing',
     '--enable-sandbox',
     '--enable-security-sqlstore',
+    '--enable-shared-icu',
     '--enable-shared-media',
     '--enable-signmar',
     '--enable-simulator',

config/external/icu/moz.build

@@ -3,8 +3,6 @@
 # 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/.
 
-Library('icu')
-
 DIRS += [
     'common',
     'data',
@@ -14,5 +12,8 @@ DIRS += [
 if CONFIG['MOZ_ICU_DATA_ARCHIVE']:
     DIRS += ['stubdata']
     USE_LIBS += ['icustubdata']
+    Library('icu')
 else:
     USE_LIBS += ['icudata']
+    SharedLibrary('icu')
+    SHARED_LIBRARY_NAME = 'icu' + CONFIG['MOZ_ICU_VERSION']

intl/unicharutil/util/moz.build

@@ -24,7 +24,10 @@ include('objs.mozbuild')
 
 UNIFIED_SOURCES += intl_unicharutil_util_cppsrcs
 
-Library('unicharutil_external_s')
+# This line breaks building ICU as a shared library due to a
+# SandboxValidationError from the frontend reader.
+if not CONFIG['MOZ_SHARED_ICU']:
+    Library('unicharutil_external_s')
 
 FORCE_STATIC_LIB = True
 

js/src/moz.build

@@ -611,21 +611,15 @@ if CONFIG['JS_SHARED_LIBRARY']:
     GeckoSharedLibrary('js', linkage=None)
     SHARED_LIBRARY_NAME = CONFIG['JS_LIBRARY_NAME']
     SDK_LIBRARY = True
-    if CONFIG['MOZ_ICU_DATA_ARCHIVE']:
     USE_LIBS += [
-             'icudata',
+        'icu',
     ]
 else:
     Library('js')
     FORCE_STATIC_LIB = True
     STATIC_LIBRARY_NAME = 'js_static'
     NO_EXPAND_LIBS = True
-
-if not CONFIG['MOZ_ICU_DATA_ARCHIVE']:
-    USE_LIBS += [
-        'icu',
-    ]
-else:
+    if CONFIG['MOZ_ICU_DATA_ARCHIVE']:
         # Linking 'icu' will pull in the stubdata library,
         # which the shell doesn't want, so link the other bits.
         USE_LIBS += [

old-configure.in

@@ -5144,12 +5144,13 @@ AC_SUBST(WIN32_REDIST_DIR)
 AC_SUBST(WIN_UCRT_REDIST_DIR)
 
 dnl ========================================================
-dnl ICU Support
+dnl ICU Shared Library Support
 dnl ========================================================
 
-if test "$MOZ_WIDGET_TOOLKIT" = "cocoa"; then
-    USE_ICU=1
-fi
+MOZ_ARG_ENABLE_BOOL(shared-icu,
+[  --enable-shared-icu           Build ICU as a shared library],
+    MOZ_SHARED_ICU=1,
+    MOZ_SHARED_ICU=)
 
 MOZ_CONFIG_ICU()