MIPS: Implement KeyedStoreICs to grow arrays on out-of-bound stores.

src/mips/codegen-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 71 matching lines @@
 void ElementsTransitionGenerator::GenerateSmiOnlyToDouble(
     MacroAssembler* masm, Label* fail) {
   // ----------- S t a t e -------------
   //  -- a0    : value
   //  -- a1    : key
   //  -- a2    : receiver
   //  -- ra    : return address
   //  -- a3    : target map, scratch for subsequent call
   //  -- t0    : scratch (elements)
   // -----------------------------------
-  Label loop, entry, convert_hole, gc_required;
+  Label loop, entry, convert_hole, gc_required, only_change_map, done;
   bool fpu_supported = CpuFeatures::IsSupported(FPU);
-  __ push(ra);
 
   Register scratch = t6;
 
+  // Check for empty arrays, which only require a map transition and no changes
+  // to the backing store.
   __ lw(t0, FieldMemOperand(a2, JSObject::kElementsOffset));
+  __ LoadRoot(at, Heap::kEmptyFixedArrayRootIndex);
+  __ Branch(&only_change_map, eq, at, Operand(t0));
+
+  __ push(ra);
   __ lw(t1, FieldMemOperand(t0, FixedArray::kLengthOffset));
   // t0: source FixedArray
   // t1: number of elements (smi-tagged)
 
   // Allocate new FixedDoubleArray.
   __ sll(scratch, t1, 2);
   __ Addu(scratch, scratch, FixedDoubleArray::kHeaderSize);
   __ AllocateInNewSpace(scratch, t2, t3, t5, &gc_required, NO_ALLOCATION_FLAGS);
   // t2: destination FixedDoubleArray, not tagged as heap object
   // Set destination FixedDoubleArray's length and map.
   __ LoadRoot(t5, Heap::kFixedDoubleArrayMapRootIndex);
   __ sw(t1, MemOperand(t2, FixedDoubleArray::kLengthOffset));
   __ sw(t5, MemOperand(t2, HeapObject::kMapOffset));
   // Update receiver's map.
 
   __ sw(a3, FieldMemOperand(a2, HeapObject::kMapOffset));
   __ RecordWriteField(a2,
                       HeapObject::kMapOffset,
                       a3,
                       t5,
                       kRAHasBeenSaved,
                       kDontSaveFPRegs,
-                      EMIT_REMEMBERED_SET,
+                      OMIT_REMEMBERED_SET,
                       OMIT_SMI_CHECK);
   // Replace receiver's backing store with newly created FixedDoubleArray.
   __ Addu(a3, t2, Operand(kHeapObjectTag));
   __ sw(a3, FieldMemOperand(a2, JSObject::kElementsOffset));
   __ RecordWriteField(a2,
                       JSObject::kElementsOffset,
                       a3,
                       t5,
                       kRAHasBeenSaved,
                       kDontSaveFPRegs,
@@ skipping 10 matching lines @@
   __ li(t1, Operand(kHoleNanUpper32));
   // t0: kHoleNanLower32
   // t1: kHoleNanUpper32
   // t2: end of destination FixedDoubleArray, not tagged
   // t3: begin of FixedDoubleArray element fields, not tagged
 
   if (!fpu_supported) __ Push(a1, a0);
 
   __ Branch(&entry);
 
+  __ bind(&only_change_map);
+  __ sw(a3, FieldMemOperand(a2, HeapObject::kMapOffset));
+  __ RecordWriteField(a2,
+                      HeapObject::kMapOffset,
+                      a3,
+                      t5,
+                      kRAHasBeenSaved,
+                      kDontSaveFPRegs,
+                      OMIT_REMEMBERED_SET,
+                      OMIT_SMI_CHECK);
+  __ Branch(&done);
+
   // Call into runtime if GC is required.
   __ bind(&gc_required);
   __ pop(ra);
   __ Branch(fail);
 
   // Convert and copy elements.
   __ bind(&loop);
   __ lw(t5, MemOperand(a3));
   __ Addu(a3, a3, kIntSize);
   // t5: current element
@@ skipping 32 matching lines @@
   }
   __ sw(t0, MemOperand(t3));  // mantissa
   __ sw(t1, MemOperand(t3, kIntSize));  // exponent
   __ Addu(t3, t3, kDoubleSize);
 
   __ bind(&entry);
   __ Branch(&loop, lt, t3, Operand(t2));
 
   if (!fpu_supported) __ Pop(a1, a0);
   __ pop(ra);
+  __ bind(&done);
 }
 
 
 void ElementsTransitionGenerator::GenerateDoubleToObject(
     MacroAssembler* masm, Label* fail) {
   // ----------- S t a t e -------------
   //  -- a0    : value
   //  -- a1    : key
   //  -- a2    : receiver
   //  -- ra    : return address
   //  -- a3    : target map, scratch for subsequent call
   //  -- t0    : scratch (elements)
   // -----------------------------------
-  Label entry, loop, convert_hole, gc_required;
+  Label entry, loop, convert_hole, gc_required, only_change_map;
+
+  // Check for empty arrays, which only require a map transition and no changes
+  // to the backing store.
+  __ lw(t0, FieldMemOperand(a2, JSObject::kElementsOffset));
+  __ LoadRoot(at, Heap::kEmptyFixedArrayRootIndex);
+  __ Branch(&only_change_map, eq, at, Operand(t0));
+
   __ MultiPush(a0.bit() | a1.bit() | a2.bit() | a3.bit() | ra.bit());
 
-  __ lw(t0, FieldMemOperand(a2, JSObject::kElementsOffset));
   __ lw(t1, FieldMemOperand(t0, FixedArray::kLengthOffset));
   // t0: source FixedArray
   // t1: number of elements (smi-tagged)
 
   // Allocate new FixedArray.
   __ sll(a0, t1, 1);
   __ Addu(a0, a0, FixedDoubleArray::kHeaderSize);
   __ AllocateInNewSpace(a0, t2, t3, t5, &gc_required, NO_ALLOCATION_FLAGS);
   // t2: destination FixedArray, not tagged as heap object
   // Set destination FixedDoubleArray's length and map.
@@ skipping 51 matching lines @@
 
   // Replace the-hole NaN with the-hole pointer.
   __ bind(&convert_hole);
   __ sw(t3, MemOperand(a3));
   __ Addu(a3, a3, kIntSize);
 
   __ bind(&entry);
   __ Branch(&loop, lt, a3, Operand(t1));
 
   __ MultiPop(a2.bit() | a3.bit() | a0.bit() | a1.bit());
-  // Update receiver's map.
-  __ sw(a3, FieldMemOperand(a2, HeapObject::kMapOffset));
-  __ RecordWriteField(a2,
-                      HeapObject::kMapOffset,
-                      a3,
-                      t5,
-                      kRAHasBeenSaved,
-                      kDontSaveFPRegs,
-                      EMIT_REMEMBERED_SET,
-                      OMIT_SMI_CHECK);
   // Replace receiver's backing store with newly created and filled FixedArray.
   __ sw(t2, FieldMemOperand(a2, JSObject::kElementsOffset));
   __ RecordWriteField(a2,
                       JSObject::kElementsOffset,
                       t2,
                       t5,
                       kRAHasBeenSaved,
                       kDontSaveFPRegs,
                       EMIT_REMEMBERED_SET,
                       OMIT_SMI_CHECK);
   __ pop(ra);
+
+  __ bind(&only_change_map);
+  // Update receiver's map.
+  __ sw(a3, FieldMemOperand(a2, HeapObject::kMapOffset));
+  __ RecordWriteField(a2,
+                      HeapObject::kMapOffset,
+                      a3,
+                      t5,
+                      kRAHasNotBeenSaved,
+                      kDontSaveFPRegs,
+                      OMIT_REMEMBERED_SET,
+                      OMIT_SMI_CHECK);
 }
 
 
 void StringCharLoadGenerator::Generate(MacroAssembler* masm,
                                        Register string,
                                        Register index,
                                        Register result,
                                        Label* call_runtime) {
   // Fetch the instance type of the receiver into result register.
   __ lw(result, FieldMemOperand(string, HeapObject::kMapOffset));
@@ skipping 79 matching lines @@
   __ Addu(at, string, index);
   __ lbu(result, MemOperand(at));
   __ bind(&done);
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS