Implement tracking and optimizations of packed arrays.

src/mips/code-stubs-mips.cc

Index: src/mips/code-stubs-mips.cc
diff --git a/src/mips/code-stubs-mips.cc b/src/mips/code-stubs-mips.cc
index bd353d98c8728aa046b5089d27dab407167b8e65..463be95d829d4ebfe5c187855f126a00fc738cb8 100644
--- a/src/mips/code-stubs-mips.cc
+++ b/src/mips/code-stubs-mips.cc
@@ -7364,7 +7364,7 @@ static const AheadOfTimeWriteBarrierStubList kAheadOfTime[] = {
   // KeyedStoreStubCompiler::GenerateStoreFastElement.
   { REG(a3), REG(a2), REG(t0), EMIT_REMEMBERED_SET },
   { REG(a2), REG(a3), REG(t0), EMIT_REMEMBERED_SET },
-  // ElementsTransitionGenerator::GenerateSmiOnlyToObject
+  // ElementsTransitionGenerator::GenerateMapChangeElementTransition
   // and ElementsTransitionGenerator::GenerateSmiOnlyToDouble
   // and ElementsTransitionGenerator::GenerateDoubleToObject
   { REG(a2), REG(a3), REG(t5), EMIT_REMEMBERED_SET },
@@ -7631,7 +7631,7 @@ void StoreArrayLiteralElementStub::Generate(MacroAssembler* masm) {
   Label fast_elements;
 
   __ CheckFastElements(a2, t1, &double_elements);
-  // FAST_SMI_ONLY_ELEMENTS or FAST_ELEMENTS
+  // Check Smi or Object elements
   __ JumpIfSmi(a0, &smi_element);
   __ CheckFastSmiOnlyElements(a2, t1, &fast_elements);
 
@@ -7658,8 +7658,7 @@ void StoreArrayLiteralElementStub::Generate(MacroAssembler* masm) {
   __ Ret(USE_DELAY_SLOT);
   __ mov(v0, a0);
 
-  // Array literal has ElementsKind of FAST_SMI_ONLY_ELEMENTS or
-  // FAST_ELEMENTS, and value is Smi.
+  // Array literal has FAST_* elements and value is Smi.
   __ bind(&smi_element);
   __ lw(t1, FieldMemOperand(a1, JSObject::kElementsOffset));
   __ sll(t2, a3, kPointerSizeLog2 - kSmiTagSize);