Implement ES6 rest parameters

src/arm64/full-codegen-arm64.cc

Index: src/arm64/full-codegen-arm64.cc
diff --git a/src/arm64/full-codegen-arm64.cc b/src/arm64/full-codegen-arm64.cc
index c6d32670ee7e5e99c9add5f014c7dc6a2c7cfd67..dca9244b2611d2ed5d72c8fc8edb46d29046325c 100644
--- a/src/arm64/full-codegen-arm64.cc
+++ b/src/arm64/full-codegen-arm64.cc
@@ -241,6 +241,25 @@ void FullCodeGenerator::Generate() {
     }
   }
 
+  // Possibly allocate RestParameters
+  int rest_index;
+  Variable* rest_param = scope()->rest_parameter(&rest_index);
+  if (rest_param) {
+    Comment cmnt(masm_, "[ Allocate rest parameter array");
+
+    int num_parameters = info->scope()->num_parameters();
+    int offset = num_parameters * kPointerSize;
+    __ Add(x3, fp, StandardFrameConstants::kCallerSPOffset + offset);
+    __ Mov(x2, Smi::FromInt(num_parameters));
+    __ Mov(x1, Smi::FromInt(rest_index));
+    __ Push(x3, x2, x1);
+
+    RestParamAccessStub stub(isolate());
+    __ CallStub(&stub);
+
+    SetVar(rest_param, x0, x1, x2);
+  }
+
   Variable* arguments = scope()->arguments();
   if (arguments != NULL) {
     // Function uses arguments object.
@@ -263,7 +282,7 @@ void FullCodeGenerator::Generate() {
     // The stub will rewrite receiver and parameter count if the previous
     // stack frame was an arguments adapter frame.
     ArgumentsAccessStub::Type type;
-    if (is_strict(language_mode())) {
+    if (is_strict(language_mode()) || !is_simple_parameter_list()) {

[Dmitry Lomov (no reviews), 2015/02/13 16:27:14]

Is this just temporary and we later add support for sloppy args with rest
parameters?

[caitp (gmail), 2015/02/13 16:30:45]

This is specced (FunctionDeclarationInstantiation, 9.2.13) --- always create
unmapped arguments object IsSimpleParameterList() is false

```
21. If argumentsObjectNeeded is true, then
    a. If strict is true or if simpleParameterList is false, then
        i. Let ao be CreateUnmappedArgumentsObject(argumentsList).
    b. Else,
        i. NOTE mapped argument object is only provided for non-strict functions
that don’t have a rest parameter, any parameter default value initializers, or
any destructured parameters .
        ii. Let ao be CreateMappedArgumentsObject(func, formals, argumentsList,
env).
```

[Dmitry Lomov (no reviews), 2015/02/13 16:41:08]

Ah, thanks!

       type = ArgumentsAccessStub::NEW_STRICT;
     } else if (function()->has_duplicate_parameters()) {
       type = ArgumentsAccessStub::NEW_SLOPPY_SLOW;