DataCount section (#2006)

* DataCount section

Read the DataCount section and verify that it agrees with the data
section. Also emit the DataCount section when bulk-memory is enabled
and there are a nonzero number of segments. Factor out some shared
unit test code.

1 files changed, 16 insertions, 0 deletions

diff --git a/test/unit/test_datacount.py b/test/unit/test_datacount.py
new file mode 100644
index 000000000..87ddbd58d
--- /dev/null
+++ b/test/unit/test_datacount.py
@@ -0,0 +1,16 @@
+import unittest
+from scripts.test.shared import WASM_OPT, run_process
+from utils import roundtrip, input_path
+
+
+class DataCountTest(unittest.TestCase):
+  def test_datacount(self):
+    roundtrip(self, 'bulkmem_data.wasm')
+
+  def test_bad_datacount(self):
+    path = input_path('bulkmem_bad_datacount.wasm')
+    p = run_process(WASM_OPT + ['-g', '-o', '-', path], check=False,
+                    capture_output=True)
+    self.assertNotEqual(p.returncode, 0)
+    self.assertIn('Number of segments does not agree with DataCount section',
+                  p.stderr)