Fuzz JSPI (#7148)

* Add a new "sleep" fuzzer import, that does a sleep for some ms.

* Add JSPI support in fuzz_shell.js. This is in the form of commented-out async/await
   keywords - commented out so that normal fuzzing is not impacted. When we want
   to fuzz JSPI, we uncomment them. We also apply the JSPI operations of marking
   imports and exports as suspending/promising.
   JSPI fuzzing is added to both fuzz_opt.py and ClusterFuzz's run.py.

1 files changed, 21 insertions, 1 deletions

diff --git a/test/unit/test_cluster_fuzz.py b/test/unit/test_cluster_fuzz.py
index 56250d46a..8f1d18104 100644
--- a/test/unit/test_cluster_fuzz.py
+++ b/test/unit/test_cluster_fuzz.py
@@ -274,10 +274,11 @@ class ClusterFuzz(utils.BinaryenTestCase):
         print()
 
         # To check for interesting JS file contents, we'll note how many times
-        # we build and run the wasm.
+        # we build and run the wasm, and other things like JSPI.
         seen_builds = []
         seen_calls = []
         seen_second_builds = []
+        seen_JSPIs = []
 
         for i in range(1, N + 1):
             fuzz_file = os.path.join(temp_dir.name, f'fuzz-binaryen-{i}.js')
@@ -287,6 +288,17 @@ class ClusterFuzz(utils.BinaryenTestCase):
             seen_calls.append(js.count('callExports();'))
             seen_second_builds.append(js.count('build(secondBinary);'))
 
+            # If JSPI is enabled, the async and await keywords should be
+            # enabled (uncommented).
+            if 'JSPI = 1' in js:
+                seen_JSPIs.append(1)
+                assert '/* async */' not in js
+                assert '/* await */' not in js
+            else:
+                seen_JSPIs.append(0)
+                assert '/* async */' in js
+                assert '/* await */' in js
+
         # There is always one build and one call (those are in the default
         # fuzz_shell.js), and we add a couple of operations, each with equal
         # probability to be a build or a call, so over the 100 testcases here we
@@ -323,6 +335,14 @@ class ClusterFuzz(utils.BinaryenTestCase):
 
         print()
 
+        # JSPI is done 1/4 of the time or so.
+        print('JSPIs are distributed as ~ mean 0.25')
+        print(f'mean JSPIs: {statistics.mean(seen_JSPIs)}')
+        self.assertEqual(min(seen_JSPIs), 0)
+        self.assertEqual(max(seen_JSPIs), 1)
+
+        print()
+
     # "zzz" in test name so that this runs last. If it runs first, it can be
     # confusing as it appears next to the logging of which bundle we use (see
     # setUpClass).