EMCC_FORCE_STDLIBS option

2 files changed, 14 insertions, 4 deletions

diff --git a/emcc b/emcc
index 39c4282b..2f4bad2b 100755
--- a/emcc
+++ b/emcc
@@ -1054,8 +1054,10 @@ try:
     libcxxabi_symbols = filter(lambda symbol: symbol not in libc_symbols, libcxxabi_symbols)
     libcxxabi_symbols = set(libcxxabi_symbols)
 
-    force = False # If we have libcxx, we must force inclusion of libc, since libcxx uses new internally. Note: this is kind of hacky
-
+    # If we have libcxx, we must force inclusion of libc, since libcxx uses new internally. Note: this is kind of hacky
+    # Settings this in the environment will avoid checking dependencies and make building big projects a little faster
+    force = os.environ.get('EMCC_FORCE_STDLIBS')
+    has = need = None
     for name, create, fix, library_symbols in [('libcxx',    create_libcxx,    fix_libcxx,    libcxx_symbols),
                                                ('libcxxabi', create_libcxxabi, fix_libcxxabi, libcxxabi_symbols),
                                                ('libc',      create_libc,      fix_libc,      libc_symbols)]:
@@ -1077,7 +1079,7 @@ try:
         # We need to build and link the library in
         if DEBUG: print >> sys.stderr, 'emcc: including %s' % name
         libfile = shared.Cache.get(name, create)
-        if len(has) > 0:
+        if has and len(has) > 0:
           # remove the symbols we do not need
           fixed = in_temp(uniquename(libfile)) + '.bc'
           shutil.copyfile(libfile, fixed)
@@ -1087,7 +1089,7 @@ try:
           libfile = fixed
         extra_files_to_link.append(libfile)
         force = True
-        if fix:
+        if fix and need:
           fix(need)
 
   # First, combine the bitcode files if there are several. We must also link if we have a singleton .a
diff --git a/tests/runner.py b/tests/runner.py
index 8410f888..46d040e1 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -7130,6 +7130,14 @@ def process(filename):
           self.assertIdentical(clean(open('release.js').read()), clean(open('debug%d.js' % debug).read())) # EMCC_DEBUG=1 mode must not generate different code!
           print >> sys.stderr, 'debug check %d passed too' % debug
 
+        try:
+          os.environ['EMCC_FORCE_STDLIBS'] = '1'
+          print 'EMCC_FORCE_STDLIBS'
+          do_test()
+        finally:
+          del os.environ['EMCC_FORCE_STDLIBS']
+        print >> sys.stderr, 'EMCC_FORCE_STDLIBS ok'
+
         try_delete(CANONICAL_TEMP_DIR)
       else:
         print >> sys.stderr, 'not doing debug check'