Allow bailing out of the register allocator when running out of virtual registers.

src/lithium-allocator.h

Index: src/lithium-allocator.h
===================================================================
--- src/lithium-allocator.h	(revision 10595)
+++ src/lithium-allocator.h	(working copy)
@@ -431,25 +431,14 @@
 
   static void TraceAlloc(const char* msg, ...);
 
-  // Lithium translation support.
-  // Record a use of an input operand in the current instruction.
-  void RecordUse(HValue* value, LUnallocated* operand);
-  // Record the definition of the output operand.
-  void RecordDefinition(HInstruction* instr, LUnallocated* operand);
-  // Record a temporary operand.
-  void RecordTemporary(LUnallocated* operand);
-
   // Checks whether the value of a given virtual register is tagged.
   bool HasTaggedValue(int virtual_register) const;
 
   // Returns the register kind required by the given virtual register.
   RegisterKind RequiredRegisterKind(int virtual_register) const;
 
-  // Control max function size.
-  static int max_initial_value_ids();
+  bool Allocate(LChunk* chunk);
 
-  void Allocate(LChunk* chunk);
-
   const ZoneList<LiveRange*>* live_ranges() const { return &live_ranges_; }
   const Vector<LiveRange*>* fixed_live_ranges() const {
     return &fixed_live_ranges_;
@@ -461,6 +450,15 @@
   LChunk* chunk() const { return chunk_; }
   HGraph* graph() const { return graph_; }
 
+  int GetVirtualRegister() {
+    if (next_virtual_register_ > LUnallocated::kMaxVirtualRegisters) {
+      allocation_ok_ = false;
+    }
+    return next_virtual_register_++;
+  }
+
+  bool AllocationOk() { return allocation_ok_; }
+
   void MarkAsOsrEntry() {
     // There can be only one.
     ASSERT(!has_osr_entry_);
@@ -533,7 +531,7 @@
   // Otherwise returns the live range that starts at pos and contains
   // all uses from the original range that follow pos. Uses at pos will
   // still be owned by the original range after splitting.
-  LiveRange* SplitAt(LiveRange* range, LifetimePosition pos);
+  LiveRange* SplitRangeAt(LiveRange* range, LifetimePosition pos);
 
   // Split the given range in a position from the interval [start, end].
   LiveRange* SplitBetween(LiveRange* range,
@@ -591,6 +589,9 @@
 
   LChunk* chunk_;
 
+  // Indicates success or failure during register allocation.
+  bool allocation_ok_;
+
   // During liveness analysis keep a mapping from block id to live_in sets
   // for blocks already analyzed.
   ZoneList<BitVector*> live_in_sets_;