ic-arm.cc.svn-base

Google浏览器V8内核代码

// Copyright 2006-2008 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
//       with the distribution.
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//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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#include "v8.h"

#include "codegen-inl.h"
#include "ic-inl.h"
#include "runtime.h"
#include "stub-cache.h"

namespace v8 { namespace internal {


// ----------------------------------------------------------------------------
// Static IC stub generators.
//

#define __ masm->


// Helper function used from LoadIC/CallIC GenerateNormal.
static void GenerateDictionaryLoad(MacroAssembler* masm,
                                   Label* done_label,
                                   Label* miss_label,
                                   Register t0,
                                   Register t1) {
  // Register use:
  //
  // t0 - used to hold the property dictionary.
  //
  // t1 - initially the receiver
  //    - used for the index into the property dictionary
  //    - holds the result on exit.
  //
  // r3 - used as temporary and to hold the capacity of the property
  //      dictionary.
  //
  // r2 - holds the name of the property and is unchanges.

  // Check for the absence of an interceptor.
  // Load the map into t0.
  __ ldr(t0, FieldMemOperand(t1, JSObject::kMapOffset));
  // Test the has_named_interceptor bit in the map.
  __ ldr(t0, FieldMemOperand(t1, Map::kInstanceAttributesOffset));
  __ tst(t0, Operand(1 << (Map::kHasNamedInterceptor + (3 * 8))));
  // Jump to miss if the interceptor bit is set.
  __ b(ne, miss_label);


  // Check that the properties array is a dictionary.
  __ ldr(t0, FieldMemOperand(t1, JSObject::kPropertiesOffset));
  __ ldr(r3, FieldMemOperand(t0, HeapObject::kMapOffset));
  __ cmp(r3, Operand(Factory::hash_table_map()));
  __ b(ne, miss_label);

  // Compute the capacity mask.
  const int kCapacityOffset =
      Array::kHeaderSize + Dictionary::kCapacityIndex * kPointerSize;
  __ ldr(r3, FieldMemOperand(t0, kCapacityOffset));
  __ mov(r3, Operand(r3, ASR, kSmiTagSize));  // convert smi to int
  __ sub(r3, r3, Operand(1));

  const int kElementsStartOffset =
      Array::kHeaderSize + Dictionary::kElementsStartIndex * kPointerSize;

  // Generate an unrolled loop that performs a few probes before
  // giving up. Measurements done on Gmail indicate that 2 probes
  // cover ~93% of loads from dictionaries.
  static const int kProbes = 4;
  for (int i = 0; i < kProbes; i++) {
    // Compute the masked index: (hash + i + i * i) & mask.
    __ ldr(t1, FieldMemOperand(r2, String::kLengthOffset));
    if (i > 0) __ add(t1, t1, Operand(Dictionary::GetProbeOffset(i)));
    __ and_(t1, t1, Operand(r3));

    // Scale the index by multiplying by the element size.
    ASSERT(Dictionary::kElementSize == 3);
    __ add(t1, t1, Operand(t1, LSL, 1));  // t1 = t1 * 3

    // Check if the key is identical to the name.
    __ add(t1, t0, Operand(t1, LSL, 2));
    __ ldr(ip, FieldMemOperand(t1, kElementsStartOffset));
    __ cmp(r2, Operand(ip));
    if (i != kProbes - 1) {
      __ b(eq, done_label);
    } else {
      __ b(ne, miss_label);
    }
  }

  // Check that the value is a normal property.
  __ bind(done_label);  // t1 == t0 + 4*index
  __ ldr(r3, FieldMemOperand(t1, kElementsStartOffset + 2 * kPointerSize));
  __ tst(r3, Operand(PropertyDetails::TypeField::mask() << kSmiTagSize));
  __ b(ne, miss_label);

  // Get the value at the masked, scaled index and return.
  __ ldr(t1, FieldMemOperand(t1, kElementsStartOffset + 1 * kPointerSize));
}


void LoadIC::GenerateArrayLength(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- r2    : name
  //  -- lr    : return address
  //  -- [sp]  : receiver
  // -----------------------------------

  Label miss;

  __ ldr(r0, MemOperand(sp, 0));

  // Check that the receiver isn't a smi.
  __ tst(r0, Operand(kSmiTagMask));
  __ b(eq, &miss);

  // Check that the object is a JS array.
  __ ldr(r1, FieldMemOperand(r0, HeapObject::kMapOffset));
  __ ldrb(r1, FieldMemOperand(r1, Map::kInstanceTypeOffset));
  __ cmp(r1, Operand(JS_ARRAY_TYPE));
  __ b(ne, &miss);

  // Load length directly from the JS array.
  __ ldr(r0, FieldMemOperand(r0, JSArray::kLengthOffset));
  __ Ret();

  // Cache miss: Jump to runtime.
  __ bind(&miss);
  Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Miss));
  __ Jump(ic, RelocInfo::CODE_TARGET);
}


void LoadIC::GenerateShortStringLength(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- r2    : name
  //  -- lr    : return address
  //  -- [sp]  : receiver
  // -----------------------------------

  Label miss;

  __ ldr(r0, MemOperand(sp, 0));

  // Check that the receiver isn't a smi.
  __ tst(r0, Operand(kSmiTagMask));
  __ b(eq, &miss);

  // Check that the object is a short string.
  __ ldr(r1, FieldMemOperand(r0, HeapObject::kMapOffset));
  __ ldrb(r1, FieldMemOperand(r1, Map::kInstanceTypeOffset));
  __ and_(r1, r1, Operand(kIsNotStringMask | kStringSizeMask));
  // The cast is to resolve the overload for the argument of 0x0.
  __ cmp(r1, Operand(static_cast<int32_t>(kStringTag | kShortStringTag)));
  __ b(ne, &miss);

  // Load length directly from the string.
  __ ldr(r0, FieldMemOperand(r0, String::kLengthOffset));
  __ mov(r0, Operand(r0, LSR, String::kShortLengthShift));
  __ mov(r0, Operand(r0, LSL, kSmiTagSize));
  __ Ret();

  // Cache miss: Jump to runtime.
  __ bind(&miss);
  Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Miss));
  __ Jump(ic, RelocInfo::CODE_TARGET);
}


void LoadIC::GenerateMediumStringLength(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- r2    : name
  //  -- lr    : return address
  //  -- [sp]  : receiver
  // -----------------------------------

  Label miss;

  __ ldr(r0, MemOperand(sp, 0));

  // Check that the receiver isn't a smi.
  __ tst(r0, Operand(kSmiTagMask));
  __ b(eq, &miss);

  // Check that the object is a medium string.
  __ ldr(r1, FieldMemOperand(r0, HeapObject::kMapOffset));
  __ ldrb(r1, FieldMemOperand(r1, Map::kInstanceTypeOffset));
  __ and_(r1, r1, Operand(kIsNotStringMask | kStringSizeMask));
  __ cmp(r1, Operand(kStringTag | kMediumStringTag));
  __ b(ne, &miss);

  // Load length directly from the string.
  __ ldr(r0, FieldMemOperand(r0, String::kLengthOffset));
  __ mov(r0, Operand(r0, LSR, String::kMediumLengthShift));
  __ mov(r0, Operand(r0, LSL, kSmiTagSize));
  __ Ret();

  // Cache miss: Jump to runtime.
  __ bind(&miss);
  Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Miss));
  __ Jump(ic, RelocInfo::CODE_TARGET);
}


void LoadIC::GenerateLongStringLength(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- r2    : name
  //  -- lr    : return address
  //  -- [sp]  : receiver
  // -----------------------------------

  Label miss;

  __ ldr(r0, MemOperand(sp, 0));
  // Check that the receiver isn't a smi.
  __ tst(r0, Operand(kSmiTagMask));
  __ b(eq, &miss);

  // Check that the object is a long string.
  __ ldr(r1, FieldMemOperand(r0, HeapObject::kMapOffset));
  __ ldrb(r1, FieldMemOperand(r1, Map::kInstanceTypeOffset));
  __ and_(r1, r1, Operand(kIsNotStringMask | kStringSizeMask));
  __ cmp(r1, Operand(kStringTag | kLongStringTag));
  __ b(ne, &miss);

  // Load length directly from the string.
  __ ldr(r0, FieldMemOperand(r0, String::kLengthOffset));
  __ mov(r0, Operand(r0, LSR, String::kLongLengthShift));
  __ mov(r0, Operand(r0, LSL, kSmiTagSize));
  __ Ret();

  // Cache miss: Jump to runtime.
  __ bind(&miss);
  Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Miss));
  __ Jump(ic, RelocInfo::CODE_TARGET);
}


void LoadIC::GenerateFunctionPrototype(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- r2    : name
  //  -- lr    : return address
  //  -- [sp]  : receiver
  // -----------------------------------

  // NOTE: Right now, this code always misses on ARM which is
  // sub-optimal. We should port the fast case code from IA-32.

  Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Miss));
  __ Jump(ic, RelocInfo::CODE_TARGET);
}


// Defined in ic.cc.
Object* CallIC_Miss(Arguments args);

void CallIC::GenerateMegamorphic(MacroAssembler* masm, int argc) {
  // ----------- S t a t e -------------
  //  -- lr: return address
  // -----------------------------------
  Label number, non_number, non_string, boolean, probe, miss;

  // Get the receiver of the function from the stack into r1.
  __ ldr(r1, MemOperand(sp, argc * kPointerSize));
  // Get the name of the function from the stack; 1 ~ receiver.
  __ ldr(r2, MemOperand(sp, (argc + 1) * kPointerSize));

  // Probe the stub cache.