Fix some defects identifies by Coverity Prevent. All are false

positives, but I've restructured the code to be more explicit.

Review URL: http://codereview.chromium.org/159192

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2521 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hashmap.cc

@@ -194,7 +194,10 @@ HashMap::Entry* HashMap::Probe(void* key, uint32_t hash) {
 void HashMap::Initialize(uint32_t capacity) {
   ASSERT(IsPowerOf2(capacity));
   map_ = reinterpret_cast<Entry*>(allocator_->New(capacity * sizeof(Entry)));
-  if (map_ == NULL) V8::FatalProcessOutOfMemory("HashMap::Initialize");
+  if (map_ == NULL) {
+    V8::FatalProcessOutOfMemory("HashMap::Initialize");
+    return;
+  }
   capacity_ = capacity;
   Clear();
 }

src/ia32/codegen-ia32.cc

@@ -3857,7 +3857,7 @@ Result CodeGenerator::LoadFromGlobalSlotCheckExtensions(
     s = s->outer_scope();
   }
 
-  if (s->is_eval_scope()) {
+  if (s != NULL && s->is_eval_scope()) {
     // Loop up the context chain.  There is no frame effect so it is
     // safe to use raw labels here.
     Label next, fast;
@@ -5388,12 +5388,6 @@ void CodeGenerator::VisitUnaryOperation(UnaryOperation* node) {
   } else {
     Load(node->expression());
     switch (op) {
-      case Token::NOT:
-      case Token::DELETE:
-      case Token::TYPEOF:
-        UNREACHABLE();  // handled above
-        break;
-
       case Token::SUB: {
         bool overwrite =
             (node->AsBinaryOperation() != NULL &&
@@ -5448,6 +5442,8 @@ void CodeGenerator::VisitUnaryOperation(UnaryOperation* node) {
       }
 
       default:
+        // NOT, DELETE, TYPEOF, and VOID are handled outside the
+        // switch.
         UNREACHABLE();
     }
   }

src/zone.cc

@@ -176,7 +176,10 @@ Address Zone::NewExpand(int size) {
     new_size = Max(kSegmentOverhead + size, kMaximumSegmentSize);
   }
   Segment* segment = Segment::New(new_size);
-  if (segment == NULL) V8::FatalProcessOutOfMemory("Zone");
+  if (segment == NULL) {
+    V8::FatalProcessOutOfMemory("Zone");
+    return NULL;
+  }
 
   // Recompute 'top' and 'limit' based on the new segment.
   Address result = RoundUp(segment->start(), kAlignment);