[wasm-gc] Fix WasmJSFunction polymorphic spec-inlining

{WasmInternalFunction::external} might return a function that is not
a WasmExportedFunction, at which point the code in ProcessTypeFeedback
fails.

See crrev.com/c/3277878 for context.

Bug: v8:12436, v8:12166
Change-Id: I09ef96df3fc051586044dd9c2ce88d6aeeb34b9f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3306391
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78139}

src/wasm/module-compiler.cc

@@ -1256,8 +1256,9 @@ std::vector<CallSiteFeedback> ProcessTypeFeedback(
     if (value.IsWasmInternalFunction() &&
         WasmExportedFunction::IsWasmExportedFunction(
             WasmInternalFunction::cast(value).external())) {
-      // Monomorphic. Mark the target for inlining if it's defined in the
-      // same module.
+      // Monomorphic, and the internal function points to a wasm-generated
+      // external function (WasmExportedFunction). Mark the target for inlining
+      // if it's defined in the same module.
       WasmExportedFunction target = WasmExportedFunction::cast(
           WasmInternalFunction::cast(value).external());
       if (target.instance() == *instance &&
@@ -1288,16 +1289,25 @@ std::vector<CallSiteFeedback> ProcessTypeFeedback(
         double frequency = static_cast<double>(this_count) / total_count;
         if (frequency > best_frequency) best_frequency = frequency;
         if (frequency < 0.8) continue;
-        Object maybe_target = polymorphic.get(j);
-        if (!maybe_target.IsWasmInternalFunction()) {
+
+        // We reject this polymorphic entry if:
+        // - it is not defined,
+        // - it is not a wasm-defined function (WasmExportedFunction)
+        // - it was not defined in this module.
+        if (!polymorphic.get(j).IsWasmInternalFunction()) continue;
+        WasmInternalFunction internal =
+            WasmInternalFunction::cast(polymorphic.get(j));
+        if (!WasmExportedFunction::IsWasmExportedFunction(
+                internal.external())) {
           continue;
         }
-        WasmExportedFunction target = WasmExportedFunction::cast(
-            WasmInternalFunction::cast(polymorphic.get(j)).external());
+        WasmExportedFunction target =
+            WasmExportedFunction::cast(internal.external());
         if (target.instance() != *instance ||
             target.function_index() < imported_functions) {
           continue;
         }
+
         found_target = target.function_index();
         found_count = static_cast<int>(this_count);
         if (FLAG_trace_wasm_speculative_inlining) {
@@ -1317,6 +1327,10 @@ std::vector<CallSiteFeedback> ProcessTypeFeedback(
     // If we fall through to here, then this call isn't eligible for inlining.
     // Possible reasons: uninitialized or megamorphic feedback; or monomorphic
     // or polymorphic that didn't meet our requirements.
+    if (FLAG_trace_wasm_speculative_inlining) {
+      PrintF("[Function #%d call_ref #%d *not* inlineable]\n", func_index,
+             i / 2);
+    }
     result[i / 2] = {-1, -1};
   }
   return result;

test/mjsunit/wasm/speculative-inlining.js

@@ -3,8 +3,9 @@
 // found in the LICENSE file.
 
 // Flags: --wasm-speculative-inlining --experimental-wasm-return-call
-// Flags: --experimental-wasm-typed-funcref --allow-natives-syntax
+// Flags: --experimental-wasm-typed-funcref --experimental-wasm-type-reflection
 // Flags: --no-wasm-tier-up --wasm-dynamic-tiering --wasm-tiering-budget=100
+// Flags: --allow-natives-syntax
 
 // These tests check if functions are speculatively inlined as expected. We do
 // not check automatically which functions are inlined. To get more insight, run
@@ -70,6 +71,7 @@ d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
     .exportAs("main");
 
   let instance = builder.instantiate();
+
   // Run 'main' until it is tiered-up.
   while (%IsLiftoffFunction(instance.exports.main)) {
     assertEquals(14, instance.exports.main(10, 1));
@@ -184,8 +186,50 @@ d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
 
   // Run 'main' until it is tiered-up.
   while (%IsLiftoffFunction(instance2.exports.main)) {
-    instance2.exports.main(0, instance1.exports.f1);
+    assertEquals(1, instance2.exports.main(0, instance1.exports.f1));
   }
   // The function f1 defined in another module should not be inlined.
-  instance2.exports.main(0, instance1.exports.f1);
+  assertEquals(1, instance2.exports.main(0, instance1.exports.f1));
+})();
+
+// Check that we handle WasmJSFunctions properly and do not inline them, both
+// in the monomorphic and polymorphic case.
+(function CallRefWasmJsFunction() {
+  print(arguments.callee.name);
+
+  let f1 = new WebAssembly.Function({parameters: ["i32"], results: ["i32"]},
+                                    x => x + 1);
+  let f2 = new WebAssembly.Function({parameters: ["i32"], results: ["i32"]},
+                                    x => x * 2);
+
+  let instance2 = function() {
+    let builder = new WasmModuleBuilder();
+
+    let sig = builder.addType(kSig_i_i);
+
+    builder.addFunction("main", makeSig(
+        [kWasmI32, wasmRefType(sig), wasmRefType(sig)], [kWasmI32]))
+      .addBody([kExprLocalGet, 0, kExprLocalGet, 1, kExprCallRef,
+                kExprLocalGet, 0, kExprLocalGet, 2, kExprCallRef,
+                kExprI32Add])
+      .exportFunc();
+
+    return builder.instantiate({});
+  }();
+
+  var i = 0;
+  // Run 'main' until it is tiered-up. The first argument should try to be
+  // spec-inlined monomorphically. We pass f2 to the second argument 80% of the
+  // time, so it should try to be spec-inlined polymorphically.
+  while (%IsLiftoffFunction(instance2.exports.main)) {
+    if (i % 5 == 0) {
+      assertEquals(12, instance2.exports.main(5, f1, f1));
+    } else {
+      assertEquals(16, instance2.exports.main(5, f1, f2));
+    }
+    i++;
+  }
+  // WebAssembly.Function objects should not be inlined.
+  assertEquals(16, instance2.exports.main(5, f1, f2));
+  assertEquals(12, instance2.exports.main(5, f1, f1));
 })();