[heap] Fix immovable {Code} allocation in no-snap builds.

R=mlippautz@chromium.org
BUG=v8:6792

Change-Id: I4b148b4bcb6e3cb73bc58eaad61d52a14da19a35
Reviewed-on: https://chromium-review.googlesource.com/760739Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49278}

src/code-stubs.cc

@@ -172,8 +172,7 @@ Handle<Code> CodeStub::GetCode() {
   }
 
   Activate(code);
-  DCHECK(!NeedsImmovableCode() || Heap::IsImmovable(code) ||
-         heap->code_space()->FirstPage()->Contains(code->address()));
+  DCHECK(!NeedsImmovableCode() || Heap::IsImmovable(code));
   return Handle<Code>(code, isolate());
 }
 

src/deoptimizer.cc

@@ -1795,7 +1795,7 @@ void Deoptimizer::EnsureCodeForDeoptimizationEntry(Isolate* isolate,
   Handle<Code> code = isolate->factory()->NewCode(
       desc, Code::STUB, Handle<Object>(), MaybeHandle<HandlerTable>(),
       MaybeHandle<ByteArray>(), MaybeHandle<DeoptimizationData>(), true);
-  CHECK(isolate->heap()->IsImmovable(*code));
+  CHECK(Heap::IsImmovable(*code));
 
   CHECK_NULL(data->deopt_entry_code_[type]);
   data->deopt_entry_code_[type] = *code;

src/heap/heap.cc

@@ -3031,12 +3031,11 @@ AllocationResult Heap::AllocateCode(int object_size, bool immovable) {
     Address address = result->address();
     MemoryChunk* chunk = MemoryChunk::FromAddress(address);
     // Code objects which should stay at a fixed address are allocated either
-    // in the first page of code space (objects on the first page of each space
-    // are never moved), in large object space, or (during snapshot creation)
-    // the containing page is marked as immovable.
-    if (!Heap::IsImmovable(result) &&
-        !code_space_->FirstPage()->Contains(address)) {
-      if (isolate()->serializer_enabled()) {
+    // in the first page of code space, in large object space, or (during
+    // snapshot creation) the containing page is marked as immovable.
+    if (!Heap::IsImmovable(result)) {
+      if (isolate()->serializer_enabled() ||
+          code_space_->FirstPage()->Contains(address)) {
         chunk->MarkNeverEvacuate();
       } else {
         // Discard the first code allocation, which was on a page where it could