X64 Crankshaft: Implement CallKeyed in optimizing compiler.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
===================================================================
--- src/x64/lithium-x64.cc	(revision 6895)
+++ src/x64/lithium-x64.cc	(working copy)
@@ -297,7 +297,7 @@
 
 
 void LCallKeyed::PrintDataTo(StringStream* stream) {
-  stream->Add("[ecx] #%d / ", arity());
+  stream->Add("[rcx] #%d / ", arity());
 }
 
 
@@ -1216,8 +1216,11 @@
 
 
 LInstruction* LChunkBuilder::DoCallKeyed(HCallKeyed* instr) {
-  Abort("Unimplemented: %s", "DoCallKeyed");
-  return NULL;
+  ASSERT(instr->key()->representation().IsTagged());
+  LOperand* key = UseFixed(instr->key(), rcx);
+  argument_count_ -= instr->argument_count();
+  LCallKeyed* result = new LCallKeyed(key);
+  return MarkAsCall(DefineFixed(result, rax), instr);
 }