support -E in emcc

2 files changed, 15 insertions, 0 deletions

diff --git a/emcc b/emcc
index 9cefa742..eea3b782 100755
--- a/emcc
+++ b/emcc
@@ -663,6 +663,12 @@ if '-M' in sys.argv or '-MM' in sys.argv:
   logging.debug('just dependencies: ' + ' '.join(cmd))
   exit(subprocess.call(cmd))
 
+if '-E' in sys.argv:
+  # Just run the preprocessor
+  cmd = [CC] + sys.argv[1:]
+  logging.debug('just preprocssor ' + ' '.join(cmd))
+  exit(subprocess.call(cmd))
+
 # Check if a target is specified
 target = None
 for i in range(len(sys.argv)-1):
diff --git a/tests/test_other.py b/tests/test_other.py
index fd1a6245..c6f5c333 100644
--- a/tests/test_other.py
+++ b/tests/test_other.py
@@ -1884,3 +1884,12 @@ you should see two lines of text in different colors and a blue rectangle
 SDL_Quit called (and ignored)
 done.
 ''' in output, output
+
+  def test_preprocess(self):
+    self.clear()
+
+    out, err = Popen([PYTHON, EMCC, path_from_root('tests', 'hello_world.c'), '-E'], stdout=PIPE).communicate()
+    assert not os.path.exists('a.out.js')
+    assert '''tests/hello_world.c"''' in out
+    assert '''printf("hello, world!''' in out
+