Make valgrind a bit more happy by zero-terminating/initializing strings.

Tiny cleanup on the way...

Review URL: https://codereview.chromium.org/1007283006

Cr-Commit-Position: refs/heads/master@{#27226}

src/compiler/graph-visualizer.cc

@@ -27,9 +27,9 @@ namespace compiler {
 
 FILE* OpenVisualizerLogFile(CompilationInfo* info, const char* phase,
                             const char* suffix, const char* mode) {
-  EmbeddedVector<char, 256> filename;
+  EmbeddedVector<char, 256> filename(0);
   SmartArrayPointer<char> function_name;
-  if (!info->shared_info().is_null()) {
+  if (info->has_shared_info()) {
     function_name = info->shared_info()->DebugName()->ToCString();
     if (strlen(function_name.get()) > 0) {
       SNPrintF(filename, "turbo-%s", function_name.get());

src/compiler/pipeline.cc

@@ -291,20 +291,17 @@ static void TraceSchedule(Schedule* schedule) {
 
 
 static SmartArrayPointer<char> GetDebugName(CompilationInfo* info) {
-  SmartArrayPointer<char> name;
-  if (info->IsStub()) {
-    if (info->code_stub() != NULL) {
-      CodeStub::Major major_key = info->code_stub()->MajorKey();
-      const char* major_name = CodeStub::MajorName(major_key, false);
-      size_t len = strlen(major_name);
-      name.Reset(new char[len]);
-      memcpy(name.get(), major_name, len);
-    }
+  if (info->code_stub() != NULL) {
+    CodeStub::Major major_key = info->code_stub()->MajorKey();
+    const char* major_name = CodeStub::MajorName(major_key, false);
+    size_t len = strlen(major_name) + 1;
+    SmartArrayPointer<char> name(new char[len]);
+    memcpy(name.get(), major_name, len);
+    return name;
   } else {
     AllowHandleDereference allow_deref;
-    name = info->function()->debug_name()->ToCString();
+    return info->function()->debug_name()->ToCString();
   }
-  return name;
 }