[wasm] Initialize the root register for WASM tests.

src/compiler/code-generator.cc

 // Copyright 2013 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/compiler/code-generator.h"
 
 #include "src/address-map.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/pipeline.h"
@@ skipping 60 matching lines @@
   FrameScope frame_scope(masm(), StackFrame::MANUAL);
 
   // Emit a code line info recording start event.
   PositionsRecorder* recorder = masm()->positions_recorder();
   LOG_CODE_EVENT(isolate(), CodeStartLinePosInfoRecordEvent(recorder));
 
   // Place function entry hook if requested to do so.
   if (linkage()->GetIncomingDescriptor()->IsJSFunctionCall()) {
     ProfileEntryHookStub::MaybeCallEntryHook(masm());
   }
-
   // Architecture-specific, linkage-specific prologue.
   info->set_prologue_offset(masm()->pc_offset());
   AssemblePrologue();
+  if (linkage()->GetIncomingDescriptor()->InitializeRootRegister()) {
+    masm()->InitializeRootRegister();
+  }
 
   // Define deoptimization literals for all inlined functions.
   DCHECK_EQ(0u, deoptimization_literals_.size());
   for (auto& inlined : info->inlined_functions()) {
     if (!inlined.shared_info.is_identical_to(info->shared_info())) {
       DefineDeoptimizationLiteral(inlined.shared_info);
     }
   }
   inlined_function_count_ = deoptimization_literals_.size();
 
@@ skipping 633 matching lines @@
     : frame_(gen->frame()), masm_(gen->masm()), next_(gen->ools_) {
   gen->ools_ = this;
 }
 
 
 OutOfLineCode::~OutOfLineCode() {}
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8