Fix fuzz issue with ElementSegment name collisions (#3674)

Now that they have names they can collide. All the fuzzer wants is
to ensure there is a segment to add to, so if there is one, do not
add another.

1 files changed, 10 insertions, 12 deletions

diff --git a/src/tools/fuzzing.h b/src/tools/fuzzing.h
index 288fdc23c..de03e943b 100644
--- a/src/tools/fuzzing.h
+++ b/src/tools/fuzzing.h
@@ -425,23 +425,20 @@ private:
 
   // TODO(reference-types): allow the fuzzer to create multiple tables
   void setupTables() {
-    if (wasm.tables.size() > 0) {
-      auto& table = wasm.tables[0];
-      table->initial = table->max = 0;
-
-      auto segment = std::make_unique<ElementSegment>(
-        table->name, builder.makeConst(int32_t(0)));
-      segment->setName(Name::fromInt(0), false);
-      wasm.addElementSegment(std::move(segment));
-    } else {
+    // Ensure an element segment, adding one or even adding a whole table as
+    // needed.
+    if (wasm.tables.empty()) {
       auto table = builder.makeTable(
         Names::getValidTableName(wasm, "fuzzing_table"), 0, 0);
       table->hasExplicitName = true;
+      wasm.addTable(std::move(table));
+    }
+    if (wasm.elementSegments.empty()) {
+      // TODO: use a random table
       auto segment = std::make_unique<ElementSegment>(
-        table->name, builder.makeConst(int32_t(0)));
-      segment->setName(Name::fromInt(0), false);
+        wasm.tables[0]->name, builder.makeConst(int32_t(0)));
+      segment->setName(Names::getValidElementSegmentName(wasm, "elem$"), false);
       wasm.addElementSegment(std::move(segment));
-      wasm.addTable(std::move(table));
     }
   }
 
@@ -1483,6 +1480,7 @@ private:
     for (const auto& type : targetFn->sig.params) {
       args.push_back(make(type));
     }
+    // TODO: use a random table
     return builder.makeCallIndirect(
       wasm.tables[0]->name, target, args, targetFn->sig, isReturn);
   }