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.

5 files changed, 43 insertions, 22 deletions

diff --git a/test/unit/input/bulkmem_bad_datacount.wasm b/test/unit/input/bulkmem_bad_datacount.wasm
new file mode 100755
index 000000000..e7b6e4bb7
--- /dev/null
+++ b/test/unit/input/bulkmem_bad_datacount.wasm
diff --git a/test/unit/input/bulkmem_data.wasm b/test/unit/input/bulkmem_data.wasm
new file mode 100755
index 000000000..aa9e535b5
--- /dev/null
+++ b/test/unit/input/bulkmem_data.wasm
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)
diff --git a/test/unit/test_features.py b/test/unit/test_features.py
index f130e1408..1672b957a 100644
--- a/test/unit/test_features.py
+++ b/test/unit/test_features.py
@@ -1,6 +1,7 @@
 import os
 import unittest
-from scripts.test.shared import WASM_OPT, run_process, options
+from scripts.test.shared import WASM_OPT, run_process
+from utils import input_path, roundtrip
 
 
 class FeatureValidationTest(unittest.TestCase):
@@ -117,50 +118,40 @@ class FeatureValidationTest(unittest.TestCase):
 
 class TargetFeaturesSectionTest(unittest.TestCase):
   def disassemble(self, filename):
-    path = os.path.join(options.binaryen_test, 'unit', 'input', filename)
+    path = input_path(filename)
     p = run_process(WASM_OPT + ['--print', '-o', os.devnull, path], check=False,
                     capture_output=True)
     self.assertEqual(p.returncode, 0)
     self.assertEqual(p.stderr, '')
     return p.stdout
 
-  def roundtrip(self, filename):
-    path = os.path.join(options.binaryen_test, 'unit', 'input', filename)
-    p = run_process(WASM_OPT + ['-g', '-o', '-', path], check=False,
-                    capture_output=True)
-    self.assertEqual(p.returncode, 0)
-    self.assertEqual(p.stderr, '')
-    with open(path, 'rb') as f:
-      self.assertEqual(str(p.stdout), str(f.read()))
-
   def test_atomics(self):
-    self.roundtrip('atomics_target_feature.wasm')
+    roundtrip(self, 'atomics_target_feature.wasm')
     module = self.disassemble('atomics_target_feature.wasm')
     self.assertIn('i32.atomic.rmw.add', module)
 
   def test_bulk_memory(self):
-    self.roundtrip('bulkmem_target_feature.wasm')
+    roundtrip(self, 'bulkmem_target_feature.wasm')
     module = self.disassemble('bulkmem_target_feature.wasm')
     self.assertIn('memory.copy', module)
 
   def test_nontrapping_fptoint(self):
-    self.roundtrip('truncsat_target_feature.wasm')
+    roundtrip(self, 'truncsat_target_feature.wasm')
     module = self.disassemble('truncsat_target_feature.wasm')
     self.assertIn('i32.trunc_sat_f32_u', module)
 
   def test_sign_ext(self):
-    self.roundtrip('signext_target_feature.wasm')
+    roundtrip(self, 'signext_target_feature.wasm')
     module = self.disassemble('signext_target_feature.wasm')
     self.assertIn('i32.extend8_s', module)
 
   def test_simd(self):
-    self.roundtrip('simd_target_feature.wasm')
+    roundtrip(self, 'simd_target_feature.wasm')
     module = self.disassemble('simd_target_feature.wasm')
     self.assertIn('i32x4.splat', module)
 
   def test_incompatible_features(self):
-    path = os.path.join(options.binaryen_test, 'unit', 'input',
-                        'signext_target_feature.wasm')
+    path = input_path('signext_target_feature.wasm')
     p = run_process(
         WASM_OPT + ['--print', '-mvp', '--enable-simd', '-o', os.devnull, path],
         check=False, capture_output=True
@@ -171,8 +162,7 @@ class TargetFeaturesSectionTest(unittest.TestCase):
                   p.stderr)
 
   def test_incompatible_features_forced(self):
-    path = os.path.join(options.binaryen_test, 'unit', 'input',
-                        'signext_target_feature.wasm')
+    path = input_path('signext_target_feature.wasm')
     p = run_process(
         WASM_OPT + ['--print', '--detect-features', '-mvp', '--enable-simd',
                     '-o', os.devnull, path],
@@ -182,8 +172,7 @@ class TargetFeaturesSectionTest(unittest.TestCase):
     self.assertIn('all used features should be allowed', p.stderr)
 
   def test_explicit_detect_features(self):
-    path = os.path.join(options.binaryen_test, 'unit', 'input',
-                        'signext_target_feature.wasm')
+    path = input_path('signext_target_feature.wasm')
     p = run_process(
         WASM_OPT + ['--print', '-mvp', '--detect-features',
                     '-o', os.devnull, path],
diff --git a/test/unit/utils.py b/test/unit/utils.py
new file mode 100644
index 000000000..eaeb29d42
--- /dev/null
+++ b/test/unit/utils.py
@@ -0,0 +1,16 @@
+import os
+from scripts.test.shared import WASM_OPT, run_process, options
+
+
+def input_path(filename):
+  return os.path.join(options.binaryen_test, 'unit', 'input', filename)
+
+
+def roundtrip(testcase, filename, opts=[]):
+  path = input_path(filename)
+  p = run_process(WASM_OPT + ['-g', '-o', '-', path] + opts, check=False,
+                  capture_output=True)
+  testcase.assertEqual(p.returncode, 0)
+  testcase.assertEqual(p.stderr, '')
+  with open(path, 'rb') as f:
+    testcase.assertEqual(str(p.stdout), str(f.read()))