harmony-scoping: Implement LoadIC handler for loads from global contexts.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index ce76fbecac93a909854dfe53c8604e52a170f06e..ad446373a8d13ba9e84066483e732ba3d75dcf01 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -4641,6 +4641,14 @@ HObjectAccess HObjectAccess::ForContextSlot(int index) {
 }
 
 
+HObjectAccess HObjectAccess::ForGlobalContext(int index) {
+  DCHECK(index >= 0);
+  Portion portion = kInobject;
+  int offset = GlobalContextTable::kHeaderSize + (index + 1) * kPointerSize;

[adamk, 2014/11/07 16:57:03]

Here's that "+ 1" again. Now that it's leaking out of the GlobalContextTable
implementation, perhaps it's worth adding a constant?

+  return HObjectAccess(portion, offset, Representation::Tagged());
+}
+
+
 HObjectAccess HObjectAccess::ForJSArrayOffset(int offset) {
   DCHECK(offset >= 0);
   Portion portion = kInobject;