tolerate people issuing link commands with duplicates in them

2 files changed, 22 insertions, 0 deletions

diff --git a/tests/runner.py b/tests/runner.py
index 775225c6..9982d0ef 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -8139,6 +8139,27 @@ f.close()
 
       self.assertContained('result: 62', run_js(os.path.join(self.get_dir(), 'a.out.js')))
 
+    def test_redundant_link(self):
+      lib = "int mult() { return 1; }"
+      lib_name = os.path.join(self.get_dir(), 'libA.c')
+      open(lib_name, 'w').write(lib)
+      main = r'''
+        #include <stdio.h>
+        int mult();
+        int main() {
+          printf("result: %d\n", mult());
+          return 0;
+        }
+      '''
+      main_name = os.path.join(self.get_dir(), 'main.c')
+      open(main_name, 'w').write(main)
+
+      Building.emcc(lib_name, output_filename='libA.so')
+
+      Building.emcc(main_name, ['libA.so']*2, output_filename='a.out.js')
+
+      self.assertContained('result: 1', run_js(os.path.join(self.get_dir(), 'a.out.js')))
+
     def test_abspaths(self):
       # Includes with absolute paths are generally dangerous, things like -I/usr/.. will get to system local headers, not our portable ones.
 
diff --git a/tools/shared.py b/tools/shared.py
index fdcdbbda..0a041669 100644
--- a/tools/shared.py
+++ b/tools/shared.py
@@ -790,6 +790,7 @@ set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)''' % { 'winfix': '' if not WINDOWS e
         seen_symbols = seen_symbols.union(symbols.defs)
 
     # Finish link
+    actual_files = list(set(actual_files)) # tolerate people trying to link a.so a.so etc.
     if DEBUG: print >>sys.stderr, 'emcc: llvm-linking:', actual_files
     output = Popen([LLVM_LINK] + actual_files + ['-o', target], stdout=PIPE).communicate()[0]
     assert os.path.exists(target) and (output is None or 'Could not open input file' not in output), 'Linking error: ' + output + '\nemcc: If you get duplicate symbol errors, try --remove-duplicates'