Merged: [wasm] Fix code specialization for empty memory buffer

src/wasm/wasm-module.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <memory>
 
 #include "src/assembler-inl.h"
 #include "src/base/adapters.h"
 #include "src/base/atomic-utils.h"
 #include "src/code-stubs.h"
@@ skipping 1153 matching lines @@
       uint32_t mem_size =
           static_cast<uint32_t>(memory_->byte_length()->Number());
       LoadDataSegments(mem_start, mem_size);
 
       uint32_t old_mem_size = compiled_module_->mem_size();
       Address old_mem_start =
           compiled_module_->has_memory()
               ? static_cast<Address>(
                     compiled_module_->memory()->backing_store())
               : nullptr;
-      code_specialization.RelocateMemoryReferences(old_mem_start, old_mem_size,
-                                                   mem_start, mem_size);
+      // We might get instantiated again with the same memory. No patching
+      // needed in this case.
+      if (old_mem_start != mem_start || old_mem_size != mem_size) {
+        code_specialization.RelocateMemoryReferences(
+            old_mem_start, old_mem_size, mem_start, mem_size);
+      }
       compiled_module_->set_memory(memory_);
     }
 
     //--------------------------------------------------------------------------
     // Set up the runtime support for the new instance.
     //--------------------------------------------------------------------------
     Handle<WeakCell> weak_link = factory->NewWeakCell(instance);
 
     for (int i = num_imported_functions + FLAG_skip_compiling_wasm_funcs;
          i < code_table->length(); ++i) {
@@ skipping 1522 matching lines @@
   Handle<String> module_property_name =
       isolate->factory()->InternalizeUtf8String("module");
   Handle<String> instance_property_name =
       isolate->factory()->InternalizeUtf8String("instance");
   JSObject::AddProperty(ret, module_property_name, module, NONE);
   JSObject::AddProperty(ret, instance_property_name,
                         instance_object.ToHandleChecked(), NONE);
 
   ResolvePromise(isolate, promise, ret);
 }