Stack allocate lexical locals + hoist stack slots

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 722a5424c03dd86386af88cc41f5caf5c2d063b9..634652d6c1b39debc8e42f95ff5f043297dd8dc9 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -4266,6 +4266,9 @@ class ScopeInfo : public FixedArray {
   // Return the name of the given stack local.
   String* StackLocalName(int var);
 
+  // Return the name of the given stack local.
+  int StackLocalIndex(int var);
+
   // Return the name of the given context local.
   String* ContextLocalName(int var);
 
@@ -4374,6 +4377,8 @@ class ScopeInfo : public FixedArray {
   //    slot is used per parameter, so in total this part occupies
   //    ParameterCount() slots in the array. For other scopes than function
   //    scopes ParameterCount() is 0.
+  // 2a.StackLocalFirstSlot:

[rossberg, 2015/04/21 14:41:02]

Nit: care to renumber?

[Dmitry Lomov (no reviews), 2015/04/21 16:59:24]

Done.

+  //    Index of a first stack slot for stack local.

[rossberg, 2015/04/21 14:41:01]

Can you please expand on this comment? It is rather central for understanding
the stack/scope layout, and this doesn't do it justice.

[Dmitry Lomov (no reviews), 2015/04/21 16:59:24]

Done.

   // 2. StackLocalEntries:
   //    Contains the names of local variables that are allocated on the stack,
   //    in increasing order of the stack slot index. One slot is used per stack
@@ -4401,6 +4406,7 @@ class ScopeInfo : public FixedArray {
   //    slots:  a. The name of the function variable.
   //            b. The context or stack slot index for the variable.
   int ParameterEntriesIndex();
+  int StackLocalFirstSlotIndex();
   int StackLocalEntriesIndex();
   int ContextLocalNameEntriesIndex();
   int ContextLocalInfoEntriesIndex();