Ensure the linker pulls in static libraries containing exported functions.

Previously, an exported function contained in a library would not be found by
the linker if the library did not contain symbols transitively reachable from
main.

1 files changed, 33 insertions, 0 deletions

diff --git a/tests/runner.py b/tests/runner.py
index 84e8b69e..86ae5bdb 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -11595,6 +11595,39 @@ int main(int argc, char const *argv[])
 
       self.assertContained('a\nb\n', run_js(os.path.join(self.get_dir(), 'a.out.js')))
 
+    def test_export_in_a(self):
+      export_name = 'this_is_an_entry_point'
+
+      open('export.c', 'w').write(r'''
+        #include <stdio.h>
+        void %s(void) {
+          printf("Hello, world!\n");
+        }
+      ''' % export_name)
+      Popen([PYTHON, EMCC, 'export.c', '-c', '-o', 'export.o']).communicate()
+      Popen([PYTHON, EMAR, 'rc', 'libexport.a', 'export.o']).communicate()
+
+      open('main.c', 'w').write(r'''
+        int main() {
+          return 0;
+        }
+      ''')
+
+      definition = 'function _%s(' % export_name
+
+      # Sanity check: the symbol should not be linked in if not requested.
+      Popen([PYTHON, EMCC, 'main.c', '-L.', '-lexport']).communicate()
+      self.assertNotContained(definition, open(os.path.join(self.get_dir(), 'a.out.js')).read())
+
+      # Sanity check: exporting without a definition does not cause it to appear.
+      # Note: exporting main prevents emcc from warning that it generated no code.
+      Popen([PYTHON, EMCC, 'main.c', '-s', '''EXPORTED_FUNCTIONS=['_main', '_%s']''' % export_name]).communicate()
+      self.assertNotContained(definition, open(os.path.join(self.get_dir(), 'a.out.js')).read())
+
+      # Actual test: defining symbol in library and exporting it causes it to appear in the output.
+      Popen([PYTHON, EMCC, 'main.c', '-L.', '-lexport', '-s', '''EXPORTED_FUNCTIONS=['_%s']''' % export_name]).communicate()
+      self.assertContained(definition, open(os.path.join(self.get_dir(), 'a.out.js')).read())
+
     def test_embed_file(self):
       open(os.path.join(self.get_dir(), 'somefile.txt'), 'w').write('''hello from a file with lots of data and stuff in it thank you very much''')
       open(os.path.join(self.get_dir(), 'main.cpp'), 'w').write(r'''