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

src/wasm/wasm-text.cc

 // 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.
 
 #include "src/wasm/wasm-text.h"
 
 #include "src/debug/interface-types.h"
 #include "src/ostreams.h"
 #include "src/vector.h"
 #include "src/wasm/function-body-decoder.h"
@@ skipping 123 matching lines @@
                          const ModuleWireBytes &wire_bytes, uint32_t func_index,
                          std::ostream &os,
                          debug::WasmDisassembly::OffsetTable *offset_table) {
   DCHECK_NOT_NULL(module);
   DCHECK_GT(module->functions.size(), func_index);
   const WasmFunction *fun = &module->functions[func_index];
 
   AccountingAllocator allocator;
   Zone zone(&allocator, ZONE_NAME);
   int line_nr = 0;
-  int control_depth = 0;
+  int control_depth = 1;
 
   // Print the function signature.
   os << "func";
   WasmName fun_name = wire_bytes.GetNameOrNull(fun);
   if (IsValidFunctionName(fun_name)) {
     os << " $";
     os.write(fun_name.start(), fun_name.length());
   }
   size_t param_count = fun->sig->parameter_count();
   if (param_count) {
@@ skipping 148 matching lines @@
       default:
         UNREACHABLE();
         break;
     }
     os << '\n';
     ++line_nr;
   }
   DCHECK_EQ(0, control_depth);
   DCHECK(i.ok());
 }