PPC: Partial revert of rest parameter desugaring.

Port d3f074b2

Original commit message:
    We'll be able to optimize rest parameters in TurboFan similarly to
    the arguments array. This CL restores the previous behavior, and a
    follow-on will enable TurboFan optimization.

R=mvstanton@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1549743003

Cr-Commit-Position: refs/heads/master@{#33028}

src/full-codegen/ppc/full-codegen-ppc.cc

@@ -264,6 +264,28 @@ void FullCodeGenerator::Generate() {
     SetVar(new_target_var, r6, r3, r5);
   }
 
+  // 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;
+
+    __ addi(r6, fp, Operand(StandardFrameConstants::kCallerSPOffset + offset));
+    __ LoadSmiLiteral(r5, Smi::FromInt(num_parameters));
+    __ LoadSmiLiteral(r4, Smi::FromInt(rest_index));
+    __ LoadSmiLiteral(r3, Smi::FromInt(language_mode()));
+    __ Push(r6, r5, r4, r3);
+    function_in_register_r4 = false;
+
+    RestParamAccessStub stub(isolate());
+    __ CallStub(&stub);
+
+    SetVar(rest_param, r3, r4, r5);
+  }
+
   Variable* arguments = scope()->arguments();
   if (arguments != NULL) {
     // Function uses arguments object.

src/ppc/code-stubs-ppc.cc

@@ -1987,6 +1987,32 @@ void ArgumentsAccessStub::GenerateNewStrict(MacroAssembler* masm) {
 }
 
 
+void RestParamAccessStub::GenerateNew(MacroAssembler* masm) {
+  // Stack layout on entry.
+  //  sp[0] : language mode
+  //  sp[4] : index of rest parameter
+  //  sp[8] : number of parameters
+  //  sp[12] : receiver displacement
+
+  Label runtime;
+  __ LoadP(r5, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
+  __ LoadP(r6, MemOperand(r5, StandardFrameConstants::kContextOffset));
+  __ CmpSmiLiteral(r6, Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR), r0);
+  __ bne(&runtime);
+
+  // Patch the arguments.length and the parameters pointer.
+  __ LoadP(r4, MemOperand(r5, ArgumentsAdaptorFrameConstants::kLengthOffset));
+  __ StoreP(r4, MemOperand(sp, 2 * kPointerSize));
+  __ SmiToPtrArrayOffset(r0, r4);
+  __ add(r6, r5, r0);
+  __ addi(r6, r6, Operand(StandardFrameConstants::kCallerSPOffset));
+  __ StoreP(r6, MemOperand(sp, 3 * kPointerSize));
+
+  __ bind(&runtime);
+  __ TailCallRuntime(Runtime::kNewRestParam, 4, 1);
+}
+
+
 void RegExpExecStub::Generate(MacroAssembler* masm) {
 // Just jump directly to runtime if native RegExp is not selected at compile
 // time or if regexp entry in generated code is turned off runtime switch or