support precompiled headers; fixes #2045

2 files changed, 37 insertions, 16 deletions

diff --git a/emcc b/emcc
index 7460da61..1942be28 100755
--- a/emcc
+++ b/emcc
@@ -61,6 +61,7 @@ BITCODE_ENDINGS = ('.bc', '.o', '.obj')
 DYNAMICLIB_ENDINGS = ('.dylib', '.so', '.dll')
 STATICLIB_ENDINGS = ('.a',)
 ASSEMBLY_ENDINGS = ('.ll',)
+HEADER_ENDINGS = ('.h', '.hxx', '.hpp', '.hh', '.H', '.HXX', '.HPP', '.HH')
 
 LIB_PREFIXES = ('', 'lib')
 
@@ -695,15 +696,12 @@ if len(sys.argv) == 1 or sys.argv[1] in ['x', 't']:
   sys.exit(0)
 
 use_cxx = True
-header = False # pre-compiled headers. We fake that by just copying the file
 
 for i in range(1, len(sys.argv)):
   arg = sys.argv[i]
   if not arg.startswith('-'):
     if arg.endswith(('.c','.m')):
       use_cxx = False
-    if arg.endswith('.h') and sys.argv[i-1] != '-include':
-      header = True
 
 if '-M' in sys.argv or '-MM' in sys.argv:
   # Just output dependencies, do not compile. Warning: clang and gcc behave differently with -MF! (clang seems to not recognize it)
@@ -737,15 +735,6 @@ if '.' in target:
 else:
   final_suffix = ''
 
-if header: # header or such
-  if len(sys.argv) >= 3: # if there is a source and a target, then copy, otherwise do nothing
-    sys.argv = filter(lambda arg: not arg.startswith('-I'), sys.argv)
-    logging.debug('Just copy:' + sys.argv[-1] + target)
-    shutil.copy(sys.argv[-1], target)
-  else:
-    logging.debug('No-op.')
-  exit(0)
-
 if TEMP_DIR:
   temp_dir = TEMP_DIR
   if os.path.exists(temp_dir):
@@ -1062,6 +1051,7 @@ try:
 
   input_files = []
   has_source_inputs = False
+  has_header_inputs = False
   lib_dirs = [shared.path_from_root('system', 'local', 'lib'),
               shared.path_from_root('system', 'lib')]
   libs = []
@@ -1073,7 +1063,7 @@ try:
       prev = newargs[i-1]
       if prev in ['-MT', '-MF', '-MQ', '-D', '-U', '-o', '-x', '-Xpreprocessor', '-include', '-imacros', '-idirafter', '-iprefix', '-iwithprefix', '-iwithprefixbefore', '-isysroot', '-imultilib', '-A', '-isystem', '-iquote', '-install_name', '-compatibility_version', '-current_version', '-I', '-L']: continue # ignore this gcc-style argument
 
-    if (os.path.islink(arg) and os.path.realpath(arg).endswith(SOURCE_ENDINGS + BITCODE_ENDINGS + DYNAMICLIB_ENDINGS + ASSEMBLY_ENDINGS)):
+    if (os.path.islink(arg) and os.path.realpath(arg).endswith(SOURCE_ENDINGS + BITCODE_ENDINGS + DYNAMICLIB_ENDINGS + ASSEMBLY_ENDINGS + HEADER_ENDINGS)):
       arg = os.path.realpath(arg)
 
     if not arg.startswith('-'):
@@ -1082,11 +1072,14 @@ try:
         exit(1)
 
       arg_ending = filename_type_ending(arg)
-      if arg_ending.endswith(SOURCE_ENDINGS + BITCODE_ENDINGS + DYNAMICLIB_ENDINGS + ASSEMBLY_ENDINGS) or shared.Building.is_ar(arg): # we already removed -o <target>, so all these should be inputs
+      if arg_ending.endswith(SOURCE_ENDINGS + BITCODE_ENDINGS + DYNAMICLIB_ENDINGS + ASSEMBLY_ENDINGS + HEADER_ENDINGS) or shared.Building.is_ar(arg): # we already removed -o <target>, so all these should be inputs
         newargs[i] = ''
         if arg_ending.endswith(SOURCE_ENDINGS):
           input_files.append(arg)
           has_source_inputs = True
+        elif arg_ending.endswith(HEADER_ENDINGS):
+          input_files.append(arg)
+          has_header_inputs = True
         elif arg_ending.endswith(ASSEMBLY_ENDINGS) or shared.Building.is_bitcode(arg): # this should be bitcode, make sure it is valid
           input_files.append(arg)
         elif arg_ending.endswith(STATICLIB_ENDINGS + DYNAMICLIB_ENDINGS):
@@ -1125,7 +1118,7 @@ try:
   # -c means do not link in gcc, and for us, the parallel is to not go all the way to JS, but stop at bitcode
   has_dash_c = '-c' in newargs
   if has_dash_c:
-    assert has_source_inputs, 'Must have source code inputs to use -c'
+    assert has_source_inputs or has_header_inputs, 'Must have source code or header inputs to use -c'
     target = target_basename + '.o'
     final_suffix = 'o'
 
@@ -1159,7 +1152,7 @@ try:
     input_files = filter(lambda input_file: check(input_file), input_files)
 
   if len(input_files) == 0:
-    logging.error('no input files\nnote that input files without a known suffix are ignored, make sure your input files end with one of: ' + str(SOURCE_ENDINGS + BITCODE_ENDINGS + DYNAMICLIB_ENDINGS + STATICLIB_ENDINGS + ASSEMBLY_ENDINGS))
+    logging.error('no input files\nnote that input files without a known suffix are ignored, make sure your input files end with one of: ' + str(SOURCE_ENDINGS + BITCODE_ENDINGS + DYNAMICLIB_ENDINGS + STATICLIB_ENDINGS + ASSEMBLY_ENDINGS + HEADER_ENDINGS))
     exit(0)
 
   newargs = CC_ADDITIONAL_ARGS + newargs
@@ -1299,6 +1292,15 @@ try:
 
   log_time('parse arguments and setup')
 
+  # Precompiled headers support
+  if has_header_inputs:
+    for header in input_files:
+      assert header.endswith(HEADER_ENDINGS), 'if you have one header input, we assume you want to precompile headers, and cannot have source files or other inputs as well: ' + str(input_files) + ' : ' + header
+    args = newargs + shared.EMSDK_CXX_OPTS + input_files
+    logging.debug("running (for precompiled headers: " + call + ' ' + ' '.join(args))
+    execute([call] + args) # let compiler frontend print directly, so colors are saved (PIPE kills that)
+    sys.exit(1)
+
   # First, generate LLVM bitcode. For each input file, we get base.o with bitcode
   for input_file in input_files:
     file_ending = filename_type_ending(input_file)
diff --git a/tests/test_other.py b/tests/test_other.py
index 8895a911..74507c21 100644
--- a/tests/test_other.py
+++ b/tests/test_other.py
@@ -2324,3 +2324,22 @@ var Module = { print: function(x) { throw '<{(' + x + ')}>' } };
     output = run_js(os.path.join(self.get_dir(), 'a.out.js'), stderr=PIPE, full_output=True, engine=NODE_JS)
     assert r'<{(123456789)}>' in output, output
 
+  def test_precompiled_headers(self):
+    self.clear()
+
+    open('header.h', 'w').write('#define X 5\n')
+    Popen([PYTHON, EMCC, '-xc++-header', 'header.h', '-c']).communicate()
+    assert os.path.exists('header.h.gch')
+
+    open('src.cpp', 'w').write(r'''
+#include <stdio.h>
+int main() {
+  printf("|%d|\n", X);
+  return 0;
+}
+''')
+    Popen([PYTHON, EMCC, 'src.cpp', '-include', 'header.h']).communicate()
+
+    output = run_js(self.in_dir('a.out.js'), stderr=PIPE, full_output=True, engine=NODE_JS)
+    assert '|5|' in output, output
+