ninja: De-dup libraries and use --start/end-group

Now we aggressively de-dup the list of libraries used while linking,
and when linking with GNU ld we have to enclose all static libraries
with -Wl,--start-group and -Wl,--end-group to force the linker to
resolve all symbols recursively. This is needed when static libraries
have circular deps on each other (see included test).

The --start/end-group change is also needed for circular dependencies
between static libraries because we no longer recursively list out all
library dependencies.

The size of build.ninja for GStreamer is now down to 6.1M from 20M,
and yields a net reduction in configuration time of 10%

1 files changed, 14 insertions, 1 deletions

diff --git a/run_unittests.py b/run_unittests.py
index e3b7c5c..71448f9 100755
--- a/run_unittests.py
+++ b/run_unittests.py
@@ -139,7 +139,7 @@ class InternalTests(unittest.TestCase):
         self.assertEqual(a, ['-Ibar', '-Ifoo', '-Ibaz', '-I..', '-I.', '-O3', '-O2', '-Wall'])
 
         ## Test that reflected addition works
-        # Test that adding to a list with just one old arg works and DOES NOT yield the same array
+        # Test that adding to a list with just one old arg works and yields the same array
         a = ['-Ifoo'] + a
         self.assertEqual(a, ['-Ibar', '-Ifoo', '-Ibaz', '-I..', '-I.', '-O3', '-O2', '-Wall'])
         # Test that adding to a list with just one new arg that is not pre-pended works
@@ -148,6 +148,19 @@ class InternalTests(unittest.TestCase):
         # Test that adding to a list with two new args preserves the order
         a = ['-Ldir', '-Lbah'] + a
         self.assertEqual(a, ['-Ibar', '-Ifoo', '-Ibaz', '-I..', '-I.', '-Ldir', '-Lbah', '-Werror', '-O3', '-O2', '-Wall'])
+        # Test that adding to a list with old args does nothing
+        a = ['-Ibar', '-Ibaz', '-Ifoo'] + a
+        self.assertEqual(a, ['-Ibar', '-Ifoo', '-Ibaz', '-I..', '-I.', '-Ldir', '-Lbah', '-Werror', '-O3', '-O2', '-Wall'])
+
+        ## Test that adding libraries works
+        l = cargsfunc(c, ['-Lfoodir', '-lfoo'])
+        self.assertEqual(l, ['-Lfoodir', '-lfoo'])
+        # Adding a library and a libpath appends both correctly
+        l += ['-Lbardir', '-lbar']
+        self.assertEqual(l, ['-Lbardir', '-Lfoodir', '-lfoo', '-lbar'])
+        # Adding the same library again does nothing
+        l += ['-lbar']
+        self.assertEqual(l, ['-Lbardir', '-Lfoodir', '-lfoo', '-lbar'])
 
     def test_commonpath(self):
         from os.path import sep