[wasm] Enforce that function bodies end with the \"end\" opcode.

test/cctest/wasm/wasm-run-utils.h

 // Copyright 2016 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.
 
 #ifndef WASM_RUN_UTILS_H
 #define WASM_RUN_UTILS_H
 
 #include <setjmp.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ skipping 491 matching lines @@
   MachineOperatorBuilder* machine() { return &main_machine_; }
   CallDescriptor* descriptor() {
     if (descriptor_ == nullptr) {
       descriptor_ = testing_module_->GetWasmCallDescriptor(zone(), sig);
     }
     return descriptor_;
   }
   uint32_t function_index() { return function_->func_index; }
 
   void Build(const byte* start, const byte* end) {
-    local_decls.Prepend(zone(), &start, &end);
+    size_t locals_size = local_decls.Size();
+    size_t total_size = end - start + locals_size + 1;
+    byte* buffer = static_cast<byte*>(zone()->New(total_size));
+    // Prepend the local decls to the code.
+    local_decls.Emit(buffer);
+    // Emit the code.
+    memcpy(buffer + locals_size, start, end - start);
+    // Append an extra end opcode.
+    buffer[total_size - 1] = kExprEnd;
+
+    start = buffer;
+    end = buffer + total_size;
 
     CHECK_GE(kMaxInt, end - start);
     int len = static_cast<int>(end - start);
     function_->code_start_offset =
         testing_module_->AddBytes(Vector<const byte>(start, len));
     function_->code_end_offset = function_->code_start_offset + len;
 
     if (interpreter_) {
       // Add the code to the interpreter.
       CHECK(interpreter_->SetFunctionCodeForTesting(function_, start, end));
@@ skipping 277 matching lines @@
   void RunWasm_##name(WasmExecutionMode execution_mode)
 
 #define WASM_EXEC_COMPILED_TEST(name)                                \
   void RunWasm_##name(WasmExecutionMode execution_mode);             \
   TEST(RunWasmCompiled_##name) { RunWasm_##name(kExecuteCompiled); } \
   void RunWasm_##name(WasmExecutionMode execution_mode)
 
 }  // namespace
 
 #endif