[wasm] Ensure WasmCode always has protected instructions.

R=clemensh@chromium.org
TEST=mjsunit/regress/wasm/regress-808012
BUG=chromium:808012

Change-Id: Ia1e4527c6c845ffd01ecf5c7fa13b8b484d6ef6e
Reviewed-on: https://chromium-review.googlesource.com/899122
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51103}

src/wasm/wasm-code-manager.cc

@@ -393,13 +393,16 @@ WasmCode* NativeModule::AddAnonymousCode(Handle<Code> code,
     reloc_info.reset(new byte[code->relocation_size()]);
     memcpy(reloc_info.get(), code->relocation_start(), code->relocation_size());
   }
+  std::shared_ptr<ProtectedInstructions> protected_instructions(
+      new ProtectedInstructions(0));
   WasmCode* ret = AddOwnedCode(
       {code->instruction_start(),
        static_cast<size_t>(code->instruction_size())},
       std::move(reloc_info), static_cast<size_t>(code->relocation_size()),
       Nothing<uint32_t>(), kind, code->constant_pool_offset(),
       (code->has_safepoint_info() ? code->stack_slots() : 0),
-      (code->has_safepoint_info() ? code->safepoint_table_offset() : 0), {});
+      (code->has_safepoint_info() ? code->safepoint_table_offset() : 0),
+      protected_instructions);
   if (ret == nullptr) return nullptr;
   intptr_t delta = ret->instructions().start() - code->instruction_start();
   int mask = RelocInfo::kApplyMask | RelocInfo::kCodeTargetMask |

src/wasm/wasm-code-manager.h

@@ -120,6 +120,9 @@ class V8_EXPORT_PRIVATE WasmCode final {
   void ResetTrapHandlerIndex();
 
   const ProtectedInstructions& protected_instructions() const {
+    // TODO(mstarzinger): Code that doesn't have trapping instruction should
+    // not be required to have this vector, make it possible to be null.
+    DCHECK_NOT_NULL(protected_instructions_);
     return *protected_instructions_.get();
   }
 

test/mjsunit/regress/wasm/regress-808012.js

+// Copyright 2018 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.
+
+// Flags: --wasm-lazy-compilation
+
+load('test/mjsunit/wasm/wasm-constants.js');
+load('test/mjsunit/wasm/wasm-module-builder.js');
+
+const builder = new WasmModuleBuilder();
+builder.addFunction('test', kSig_i_i).addBody([kExprUnreachable]);
+let module = new WebAssembly.Module(builder.toBuffer());
+var worker = new Worker('onmessage = function() {};');
+worker.postMessage(module);