MIPS: Improve performance of keyed loads/stores which have a HeapNumber index.

src/mips/stub-cache-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 3353 matching lines @@
     case FAST_DOUBLE_ELEMENTS:
     case DICTIONARY_ELEMENTS:
     case NON_STRICT_ARGUMENTS_ELEMENTS:
       UNREACHABLE();
       return false;
   }
   return false;
 }
 
 
+static void GenerateSmiKeyCheck(MacroAssembler* masm,
+                                Register key,
+                                Register scratch0,
+                                Register scratch1,
+                                FPURegister double_scratch0,
+                                Label* fail) {
+  if (CpuFeatures::IsSupported(FPU)) {
+    CpuFeatures::Scope scope(FPU);
+    Label key_ok;
+    // Check for smi or a smi inside a heap number.  We convert the heap
+    // number and check if the conversion is exact and fits into the smi
+    // range.
+    __ JumpIfSmi(key, &key_ok);
+    __ CheckMap(key,
+                scratch0,
+                Heap::kHeapNumberMapRootIndex,
+                fail,
+                DONT_DO_SMI_CHECK);
+    __ ldc1(double_scratch0, FieldMemOperand(key, HeapNumber::kValueOffset));
+    __ EmitFPUTruncate(kRoundToZero,
+                       double_scratch0,
+                       double_scratch0,
+                       scratch0,
+                       scratch1,
+                       kCheckForInexactConversion);
+
+    __ Branch(fail, ne, scratch1, Operand(zero_reg));
+
+    __ mfc1(scratch0, double_scratch0);
+    __ SmiTagCheckOverflow(key, scratch0, scratch1);
+    __ BranchOnOverflow(fail, scratch1);
+    __ bind(&key_ok);
+  } else {
+    // Check that the key is a smi.
+    __ JumpIfNotSmi(key, fail);
+  }
+}
+
+
 void KeyedLoadStubCompiler::GenerateLoadExternalArray(
     MacroAssembler* masm,
     ElementsKind elements_kind) {
   // ---------- S t a t e --------------
   //  -- ra     : return address
   //  -- a0     : key
   //  -- a1     : receiver
   // -----------------------------------
   Label miss_force_generic, slow, failed_allocation;
 
   Register key = a0;
   Register receiver = a1;
 
   // This stub is meant to be tail-jumped to, the receiver must already
   // have been verified by the caller to not be a smi.
 
-  // Check that the key is a smi.
-  __ JumpIfNotSmi(key, &miss_force_generic);
+  // Check that the key is a smi or a heap number convertible to a smi.
+  GenerateSmiKeyCheck(masm, key, t0, t1, f2, &miss_force_generic);
 
   __ lw(a3, FieldMemOperand(receiver, JSObject::kElementsOffset));
   // a3: elements array
 
   // Check that the index is in range.
   __ lw(t1, FieldMemOperand(a3, ExternalArray::kLengthOffset));
   __ sra(t2, key, kSmiTagSize);
   // Unsigned comparison catches both negative and too-large values.
   __ Branch(&miss_force_generic, Ugreater_equal, key, Operand(t1));
 
@@ skipping 317 matching lines @@
 
   // Register usage.
   Register value = a0;
   Register key = a1;
   Register receiver = a2;
   // a3 mostly holds the elements array or the destination external array.
 
   // This stub is meant to be tail-jumped to, the receiver must already
   // have been verified by the caller to not be a smi.
 
-    // Check that the key is a smi.
-  __ JumpIfNotSmi(key, &miss_force_generic);
+  // Check that the key is a smi or a heap number convertible to a smi.
+  GenerateSmiKeyCheck(masm, key, t0, t1, f2, &miss_force_generic);
 
   __ lw(a3, FieldMemOperand(receiver, JSObject::kElementsOffset));
 
   // Check that the index is in range.
   __ lw(t1, FieldMemOperand(a3, ExternalArray::kLengthOffset));
   // Unsigned comparison catches both negative and too-large values.
   __ Branch(&miss_force_generic, Ugreater_equal, key, Operand(t1));
 
   // Handle both smis and HeapNumbers in the fast path. Go to the
   // runtime for all other kinds of values.
@@ skipping 358 matching lines @@
   // ----------- S t a t e -------------
   //  -- ra    : return address
   //  -- a0    : key
   //  -- a1    : receiver
   // -----------------------------------
   Label miss_force_generic;
 
   // This stub is meant to be tail-jumped to, the receiver must already
   // have been verified by the caller to not be a smi.
 
-  // Check that the key is a smi.
-  __ JumpIfNotSmi(a0, &miss_force_generic, at, USE_DELAY_SLOT);
-  // The delay slot can be safely used here, a1 is an object pointer.
+  // Check that the key is a smi or a heap number convertible to a smi.
+  GenerateSmiKeyCheck(masm, a0, t0, t1, f2, &miss_force_generic);
 
   // Get the elements array.
   __ lw(a2, FieldMemOperand(a1, JSObject::kElementsOffset));
   __ AssertFastElements(a2);
 
   // Check that the key is within bounds.
   __ lw(a3, FieldMemOperand(a2, FixedArray::kLengthOffset));
   __ Branch(USE_DELAY_SLOT, &miss_force_generic, hs, a0, Operand(a3));
 
   // Load the result and make sure it's not the hole.
@@ skipping 29 matching lines @@
   Register heap_number_reg = a2;
   Register indexed_double_offset = a3;
   Register scratch = t0;
   Register scratch2 = t1;
   Register scratch3 = t2;
   Register heap_number_map = t3;
 
   // This stub is meant to be tail-jumped to, the receiver must already
   // have been verified by the caller to not be a smi.
 
-  // Check that the key is a smi.
-  __ JumpIfNotSmi(key_reg, &miss_force_generic);
+  // Check that the key is a smi or a heap number convertible to a smi.
+  GenerateSmiKeyCheck(masm, key_reg, t0, t1, f2, &miss_force_generic);
 
   // Get the elements array.
   __ lw(elements_reg,
         FieldMemOperand(receiver_reg, JSObject::kElementsOffset));
 
   // Check that the key is within bounds.
   __ lw(scratch, FieldMemOperand(elements_reg, FixedArray::kLengthOffset));
   __ Branch(&miss_force_generic, hs, key_reg, Operand(scratch));
 
   // Load the upper word of the double in the fixed array and test for NaN.
@@ skipping 53 matching lines @@
   Register receiver_reg = a2;
   Register scratch = t0;
   Register elements_reg = a3;
   Register length_reg = t1;
   Register scratch2 = t2;
   Register scratch3 = t3;
 
   // This stub is meant to be tail-jumped to, the receiver must already
   // have been verified by the caller to not be a smi.
 
-  // Check that the key is a smi.
-  __ JumpIfNotSmi(key_reg, &miss_force_generic);
+  // Check that the key is a smi or a heap number convertible to a smi.
+  GenerateSmiKeyCheck(masm, key_reg, t0, t1, f2, &miss_force_generic);
 
   if (elements_kind == FAST_SMI_ONLY_ELEMENTS) {
     __ JumpIfNotSmi(value_reg, &transition_elements_kind);
   }
 
   // Check that the key is within bounds.
   __ lw(elements_reg,
         FieldMemOperand(receiver_reg, JSObject::kElementsOffset));
   if (is_js_array) {
     __ lw(scratch, FieldMemOperand(receiver_reg, JSArray::kLengthOffset));
@@ skipping 145 matching lines @@
   Register receiver_reg = a2;
   Register elements_reg = a3;
   Register scratch1 = t0;
   Register scratch2 = t1;
   Register scratch3 = t2;
   Register scratch4 = t3;
   Register length_reg = t3;
 
   // This stub is meant to be tail-jumped to, the receiver must already
   // have been verified by the caller to not be a smi.
-  __ JumpIfNotSmi(key_reg, &miss_force_generic);
+
+  // Check that the key is a smi or a heap number convertible to a smi.
+  GenerateSmiKeyCheck(masm, key_reg, t0, t1, f2, &miss_force_generic);
 
   __ lw(elements_reg,
          FieldMemOperand(receiver_reg, JSObject::kElementsOffset));
 
   // Check that the key is within bounds.
   if (is_js_array) {
     __ lw(scratch1, FieldMemOperand(receiver_reg, JSArray::kLengthOffset));
   } else {
     __ lw(scratch1,
           FieldMemOperand(elements_reg, FixedArray::kLengthOffset));
@@ skipping 96 matching lines @@
     __ Jump(ic_slow, RelocInfo::CODE_TARGET);
   }
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS