Implement ICs for FastDoubleArray loads and stores

src/arm/stub-cache-arm.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
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 // 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 4150 matching lines @@
   __ mov(r0, r4);
   __ Ret();
 
   __ bind(&miss_force_generic);
   Code* stub = masm->isolate()->builtins()->builtin(
       Builtins::kKeyedLoadIC_MissForceGeneric);
   __ Jump(Handle<Code>(stub), RelocInfo::CODE_TARGET);
 }
 
 
+void KeyedLoadStubCompiler::GenerateLoadFastDoubleElement(
+    MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- lr    : return address
+  //  -- r0    : key
+  //  -- r1    : receiver
+  // -----------------------------------
+  Label miss_force_generic, slow_allocate_heapnumber;
+
+  Register key_reg = r0;
+  Register receiver_reg = r1;
+  Register elements_reg = r2;
+  Register heap_number_reg = r2;
+
+  // 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);
+
+  // Get the elements array.
+  __ ldr(elements_reg,
+         FieldMemOperand(receiver_reg, JSObject::kElementsOffset));
+
+  // Check that the key is within bounds.
+  __ ldr(r3, FieldMemOperand(elements_reg, FixedArray::kLengthOffset));

[Mads Ager (chromium), 2011/07/12 12:03:26]

In the store stub you have named the scratch registers as well. I think you
should be consistent and either name them here as well or remove the naming in
the store stub.

[danno, 2011/07/13 08:59:52]

Done.

+  __ cmp(key_reg, Operand(r3));
+  __ b(hs, &miss_force_generic);
+
+  // Load the upper word of the double in the fixed array and test for NaN.
+  __ add(r3, elements_reg,
+         Operand(key_reg, LSL, kDoubleSizeLog2 - kSmiTagSize));
+  uint32_t upper_32_offset = FixedArray::kHeaderSize + Register::kSizeInBytes;

[Mads Ager (chromium), 2011/07/12 12:03:26]

This doesn't really matter, but I like sizeof(kHoleNanLower32) which you are
using in the 32-bit version better. :-)

[danno, 2011/07/13 08:59:52]

Done.

+  __ ldr(r4, FieldMemOperand(r3, upper_32_offset));
+  // Detect the upper 32 bit pattern in the double that are a sentinel for the
+  // hole by detecting an overflow when adding 1.
+  ASSERT(0x7FFFFFFF == kHoleNanUpper32);
+  __ add(r5, r4, Operand(1), SetCC);

[Rodolph Perfetta, 2011/07/12 14:00:30]

0x7FFFFFFF + 1 will not set the overflow flag, but the negative flag. Some
negative values are valid for the upper part of a double so maybe a cmp could be
used instead. The V8 assembler will replace cmp with 0x7FFFFFFF by cmn with
0x80000001 and 0x80000001 is a valid ARM immediate (no need for extra
instructions).

[danno, 2011/07/13 08:59:52]

Done.

+  __ b(&miss_force_generic, vs);
+
+  // Non Nan. Allocate a new heap number and copy the double value into it.

[Mads Ager (chromium), 2011/07/12 12:03:26]

NaN

[danno, 2011/07/13 08:59:52]

Done.

+  __ LoadRoot(r7, Heap::kHeapNumberMapRootIndex);
+  __ AllocateHeapNumber(heap_number_reg, r5, r6, r7, &slow_allocate_heapnumber);
+
+  // Don't need to reload the upper 32 bits of the double, it's already in r4.
+  __ str(r4, FieldMemOperand(heap_number_reg, HeapNumber::kExponentOffset));
+  __ ldr(r4, FieldMemOperand(r3, FixedArray::kHeaderSize));
+  __ str(r4, FieldMemOperand(heap_number_reg, HeapNumber::kMantissaOffset));
+
+  __ mov(r0, heap_number_reg);
+  __ Ret();
+
+  __ bind(&slow_allocate_heapnumber);
+  Handle<Code> slow_ic =
+      masm->isolate()->builtins()->KeyedLoadIC_Slow();
+  __ Jump(slow_ic, RelocInfo::CODE_TARGET);
+
+  __ bind(&miss_force_generic);
+  Handle<Code> miss_ic =
+      masm->isolate()->builtins()->KeyedLoadIC_MissForceGeneric();
+  __ Jump(miss_ic, RelocInfo::CODE_TARGET);
+}
+
+
 void KeyedStoreStubCompiler::GenerateStoreFastElement(MacroAssembler* masm,
                                                       bool is_js_array) {
   // ----------- S t a t e -------------
   //  -- r0    : value
   //  -- r1    : key
   //  -- r2    : receiver
   //  -- lr    : return address
   //  -- r3    : scratch
   //  -- r4    : scratch (elements)
   // -----------------------------------
@@ skipping 43 matching lines @@
   // Done.
   __ Ret();
 
   __ bind(&miss_force_generic);
   Handle<Code> ic =
       masm->isolate()->builtins()->KeyedStoreIC_MissForceGeneric();
   __ Jump(ic, RelocInfo::CODE_TARGET);
 }
 
 
+void KeyedStoreStubCompiler::GenerateStoreFastDoubleElement(
+    MacroAssembler* masm,
+    bool is_js_array) {
+  // ----------- S t a t e -------------
+  //  -- r0    : value
+  //  -- r1    : key
+  //  -- r2    : receiver
+  //  -- lr    : return address
+  //  -- r3    : scratch
+  //  -- r4    : scratch
+  //  -- r5    : scratch
+  // -----------------------------------
+  Label miss_force_generic, smi_value, is_nan, have_double_value;
+
+  Register value_reg = r0;
+  Register key_reg = r1;
+  Register receiver_reg = r2;
+  Register scratch = r3;
+  Register elements_reg = r4;
+  Register scratch2 = r5;
+  Register scratch3 = r6;
+  Register scratch4 = r7;
+
+  // 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);
+
+  __ ldr(elements_reg,
+         FieldMemOperand(receiver_reg, JSObject::kElementsOffset));
+
+  // Check that the key is within bounds.
+  if (is_js_array) {
+    __ ldr(scratch, FieldMemOperand(receiver_reg, JSArray::kLengthOffset));
+  } else {
+    __ ldr(scratch,
+           FieldMemOperand(elements_reg, FixedArray::kLengthOffset));
+  }
+  // Compare smis, unsigned compare catches both negative and out-of-bound
+  // indexes.
+  __ cmp(key_reg, scratch);
+  __ b(hs, &miss_force_generic);
+
+  // Handle smi values specially.
+  __ JumpIfSmi(value_reg, &smi_value);
+
+  // Ensure that the object is a heap number
+  __ CheckMap(value_reg,
+              scratch,
+              masm->isolate()->factory()->heap_number_map(),
+              &miss_force_generic,
+              DONT_DO_SMI_CHECK);
+
+  // Check for nan: all NaN values have a value greater (signed) than 0x7ff00000
+  // in the exponent.
+  __ mov(scratch, Operand(0x7ff00000));
+  __ ldr(scratch3, FieldMemOperand(value_reg, HeapNumber::kExponentOffset));
+  __ cmp(scratch3, scratch);
+  __ b(gt, &is_nan);
+
+  __ ldr(scratch2, FieldMemOperand(value_reg, HeapNumber::kMantissaOffset));
+
+  __ bind(&have_double_value);
+  // Double value to store in the double array is in scratch2 and scratch3.
+  __ add(scratch, elements_reg,
+         Operand(key_reg, LSL, kDoubleSizeLog2 - kSmiTagSize));
+  __ str(scratch2, FieldMemOperand(scratch, FixedDoubleArray::kHeaderSize));
+  uint32_t offset = FixedDoubleArray::kHeaderSize + Register::kSizeInBytes;
+  __ str(scratch3, FieldMemOperand(scratch, offset));
+  __ Ret();
+
+  __ bind(&is_nan);
+  __ mov(scratch2, Operand(kCanonicalNonHoleNanLower32));
+  __ mov(scratch3, Operand(kCanonicalNonHoleNanUpper32));
+  __ jmp(&have_double_value);
+
+  __ bind(&smi_value);
+  __ add(scratch, elements_reg,
+         Operand(FixedDoubleArray::kHeaderSize - kHeapObjectTag));
+  __ add(scratch, scratch,
+         Operand(key_reg, LSL, kDoubleSizeLog2 - kSmiTagSize));
+  // scratch is now effective address of the double element
+
+  FloatingPointHelper::Destination destination;
+  if (CpuFeatures::IsSupported(VFP3)) {
+    destination = FloatingPointHelper::kVFPRegisters;
+  } else {
+    destination = FloatingPointHelper::kCoreRegisters;
+  }
+  __ SmiUntag(value_reg, value_reg);
+  FloatingPointHelper::ConvertIntToDouble(
+      masm, value_reg, destination,
+      d0, scratch2, scratch3,  // These are: double_dst, dst1, dst2.
+      scratch4, s2);  // These are: scratch2, single_scratch.
+  if (destination == FloatingPointHelper::kVFPRegisters) {
+    CpuFeatures::Scope scope(VFP3);
+    __ vstr(d0, scratch, 0);
+  } else {
+    __ str(scratch2, MemOperand(scratch, 0));
+    __ str(scratch3, MemOperand(scratch, Register::kSizeInBytes));
+  }
+  __ Ret();
+
+  // Handle store cache miss, replacing the ic with the generic stub.
+  __ bind(&miss_force_generic);
+  Handle<Code> ic =
+      masm->isolate()->builtins()->KeyedStoreIC_MissForceGeneric();
+  __ Jump(ic, RelocInfo::CODE_TARGET);
+}
+
+
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM