[wasm] grow_memory(0) is the same as memory_size()

test/cctest/wasm/test-run-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 <stdlib.h>
 #include <string.h>
 
 #include "src/wasm/module-decoder.h"
 #include "src/wasm/wasm-macro-gen.h"
 #include "src/wasm/wasm-module-builder.h"
@@ skipping 265 matching lines @@
   Zone zone(&allocator);
 
   WasmModuleBuilder* builder = new (&zone) WasmModuleBuilder(&zone);
   WasmFunctionBuilder* f = builder->AddFunction(sigs.i_v());
   ExportAsMain(f);
   byte code[] = {WASM_GROW_MEMORY(WASM_I8(10)), WASM_DROP, WASM_MEMORY_SIZE};
   f->EmitCode(code, sizeof(code));
   TestModule(&zone, builder, kExpectedValue);
 }
 
+TEST(GrowMemoryZero) {
+  // Initial memory size is 16, see wasm-module-builder.cc
+  static const int kExpectedValue = 16;
+  TestSignatures sigs;
+  v8::internal::AccountingAllocator allocator;
+  Zone zone(&allocator);
+
+  WasmModuleBuilder* builder = new (&zone) WasmModuleBuilder(&zone);
+  WasmFunctionBuilder* f = builder->AddFunction(sigs.i_v());
+  ExportAsMain(f);
+  byte code[] = {WASM_GROW_MEMORY(WASM_I32V(0))};
+  f->EmitCode(code, sizeof(code));
+  TestModule(&zone, builder, kExpectedValue);
+}
+
 TEST(Run_WasmModule_GrowMemoryInIf) {
   TestSignatures sigs;
   v8::internal::AccountingAllocator allocator;
   Zone zone(&allocator);
   WasmModuleBuilder* builder = new (&zone) WasmModuleBuilder(&zone);
   WasmFunctionBuilder* f = builder->AddFunction(sigs.i_v());
   ExportAsMain(f);
   byte code[] = {WASM_IF_ELSE_I(WASM_I32V(0), WASM_GROW_MEMORY(WASM_I32V(1)),
                                 WASM_I32V(12))};
   f->EmitCode(code, sizeof(code));
@@ skipping 111 matching lines @@
   }
 
   v8::TryCatch try_catch(reinterpret_cast<v8::Isolate*>(isolate));
   Handle<Object> params[1] = {
       Handle<Object>(Smi::FromInt(25 * kPageSize), isolate)};
   testing::RunWasmModuleForTesting(isolate, instance, 1, params,
                                    ModuleOrigin::kWasmOrigin);
   CHECK(try_catch.HasCaught());
   isolate->clear_pending_exception();
 }