CSE2410 Fall 2014 Bounce

// 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

//       with the distribution.

//     * Neither the name of Google Inc. nor the names of its

//       contributors may be used to endorse or promote products derived

//       from this software without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

// 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

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef V8_ARM_CODE_STUBS_ARM_H_

#define V8_ARM_CODE_STUBS_ARM_H_

#include "ic-inl.h"

namespace v8 {

namespace internal {

void ArrayNativeCode(MacroAssembler* masm, Label* call_generic_code);

// Compute a transcendental math function natively, or call the

// TranscendentalCache runtime function.

class TranscendentalCacheStub: public PlatformCodeStub {

 public:

  enum ArgumentType {

    TAGGED = 0 << TranscendentalCache::kTranscendentalTypeBits,

    UNTAGGED = 1 << TranscendentalCache::kTranscendentalTypeBits

  };

  TranscendentalCacheStub(TranscendentalCache::Type type,

                          ArgumentType argument_type)

      : type_(type), argument_type_(argument_type) { }

  void Generate(MacroAssembler* masm);

 private:

  TranscendentalCache::Type type_;

  ArgumentType argument_type_;

  void GenerateCallCFunction(MacroAssembler* masm, Register scratch);

  Major MajorKey() { return TranscendentalCache; }

  int MinorKey() { return type_ | argument_type_; }

  Runtime::FunctionId RuntimeFunction();

};

class StoreBufferOverflowStub: public PlatformCodeStub {

 public:

  explicit StoreBufferOverflowStub(SaveFPRegsMode save_fp)

      : save_doubles_(save_fp) {}

  void Generate(MacroAssembler* masm);

  virtual bool IsPregenerated(Isolate* isolate) V8_OVERRIDE { return true; }

  static void GenerateFixedRegStubsAheadOfTime(Isolate* isolate);

  virtual bool SometimesSetsUpAFrame() { return false; }

 private:

  SaveFPRegsMode save_doubles_;

  Major MajorKey() { return StoreBufferOverflow; }

  int MinorKey() { return (save_doubles_ == kSaveFPRegs) ? 1 : 0; }

};

class StringHelper : public AllStatic {

 public:

  // Generate code for copying characters using a simple loop. This should only

  // be used in places where the number of characters is small and the

  // additional setup and checking in GenerateCopyCharactersLong adds too much

  // overhead. Copying of overlapping regions is not supported.

  // Dest register ends at the position after the last character written.

  static void GenerateCopyCharacters(MacroAssembler* masm,

                                     Register dest,

                                     Register src,

                                     Register count,

                                     Register scratch,

                                     bool ascii);

  // Generate code for copying a large number of characters. This function

  // is allowed to spend extra time setting up conditions to make copying

  // faster. Copying of overlapping regions is not supported.

  // Dest register ends at the position after the last character written.

  static void GenerateCopyCharactersLong(MacroAssembler* masm,

                                         Register dest,

                                         Register src,

                                         Register count,

                                         Register scratch1,

                                         Register scratch2,

                                         Register scratch3,

                                         Register scratch4,

                                         int flags);

  // Probe the string table for a two character string. If the string is

  // not found by probing a jump to the label not_found is performed. This jump

  // does not guarantee that the string is not in the string table. If the

  // string is found the code falls through with the string in register r0.

  // Contents of both c1 and c2 registers are modified. At the exit c1 is

  // guaranteed to contain halfword with low and high bytes equal to

  // initial contents of c1 and c2 respectively.

  static void GenerateTwoCharacterStringTableProbe(MacroAssembler* masm,

                                                   Register c1,

                                                   Register c2,

                                                   Register scratch1,

                                                   Register scratch2,

                                                   Register scratch3,

                                                   Register scratch4,

                                                   Register scratch5,

                                                   Label* not_found);

  // Generate string hash.

  static void GenerateHashInit(MacroAssembler* masm,

                               Register hash,

                               Register character);

  static void GenerateHashAddCharacter(MacroAssembler* masm,

                                       Register hash,

                                       Register character);

  static void GenerateHashGetHash(MacroAssembler* masm,

                                  Register hash);

 private:

  DISALLOW_IMPLICIT_CONSTRUCTORS(StringHelper);

};

class StringAddStub: public PlatformCodeStub {

 public:

  explicit StringAddStub(StringAddFlags flags) : flags_(flags) {}

 private:

  Major MajorKey() { return StringAdd; }

  int MinorKey() { return flags_; }

  void Generate(MacroAssembler* masm);

  void GenerateConvertArgument(MacroAssembler* masm,

                               int stack_offset,

                               Register arg,

                               Register scratch1,

                               Register scratch2,

                               Register scratch3,

                               Register scratch4,

                               Label* slow);

  void GenerateRegisterArgsPush(MacroAssembler* masm);

  void GenerateRegisterArgsPop(MacroAssembler* masm);

  const StringAddFlags flags_;

};

class SubStringStub: public PlatformCodeStub {

 public:

  SubStringStub() {}

 private:

  Major MajorKey() { return SubString; }

  int MinorKey() { return 0; }

  void Generate(MacroAssembler* masm);

};

class StringCompareStub: public PlatformCodeStub {

 public:

  StringCompareStub() { }

  // Compares two flat ASCII strings and returns result in r0.

  static void GenerateCompareFlatAsciiStrings(MacroAssembler* masm,

                                              Register left,

                                              Register right,

                                              Register scratch1,

                                              Register scratch2,

                                              Register scratch3,

                                              Register scratch4);

  // Compares two flat ASCII strings for equality and returns result

  // in r0.

  static void GenerateFlatAsciiStringEquals(MacroAssembler* masm,

                                            Register left,

                                            Register right,

                                            Register scratch1,

                                            Register scratch2,

                                            Register scratch3);

 private:

  virtual Major MajorKey() { return StringCompare; }

  virtual int MinorKey() { return 0; }

  virtual void Generate(MacroAssembler* masm);

  static void GenerateAsciiCharsCompareLoop(MacroAssembler* masm,

                                            Register left,

                                            Register right,

                                            Register length,

                                            Register scratch1,

                                            Register scratch2,

                                            Label* chars_not_equal);

};

// This stub can convert a signed int32 to a heap number (double).  It does

// not work for int32s that are in Smi range!  No GC occurs during this stub

// so you don't have to set up the frame.

class WriteInt32ToHeapNumberStub : public PlatformCodeStub {

 public:

  WriteInt32ToHeapNumberStub(Register the_int,

                             Register the_heap_number,

                             Register scratch)

      : the_int_(the_int),

        the_heap_number_(the_heap_number),

        scratch_(scratch) { }

  virtual bool IsPregenerated(Isolate* isolate) V8_OVERRIDE;

  static void GenerateFixedRegStubsAheadOfTime(Isolate* isolate);

 private:

  Register the_int_;

  Register the_heap_number_;

  Register scratch_;

  // Minor key encoding in 16 bits.

  class IntRegisterBits: public BitField<int, 0, 4> {};

  class HeapNumberRegisterBits: public BitField<int, 4, 4> {};

  class ScratchRegisterBits: public BitField<int, 8, 4> {};

  Major MajorKey() { return WriteInt32ToHeapNumber; }

  int MinorKey() {

    // Encode the parameters in a unique 16 bit value.

    return IntRegisterBits::encode(the_int_.code())

           | HeapNumberRegisterBits::encode(the_heap_number_.code())

           | ScratchRegisterBits::encode(scratch_.code());

  }

  void Generate(MacroAssembler* masm);

};

class RecordWriteStub: public PlatformCodeStub {

 public:

  RecordWriteStub(Register object,

                  Register value,

                  Register address,

                  RememberedSetAction remembered_set_action,

                  SaveFPRegsMode fp_mode)

      : object_(object),

        value_(value),

        address_(address),

        remembered_set_action_(remembered_set_action),

        save_fp_regs_mode_(fp_mode),

        regs_(object,   // An input reg.

              address,  // An input reg.

              value) {  // One scratch reg.

  }

  enum Mode {

    STORE_BUFFER_ONLY,

    INCREMENTAL,

    INCREMENTAL_COMPACTION

  };

  virtual bool IsPregenerated(Isolate* isolate) V8_OVERRIDE;

  static void GenerateFixedRegStubsAheadOfTime(Isolate* isolate);

  virtual bool SometimesSetsUpAFrame() { return false; }

  static void PatchBranchIntoNop(MacroAssembler* masm, int pos) {

    masm->instr_at_put(pos, (masm->instr_at(pos) & ~B27) | (B24 | B20));

    ASSERT(Assembler::IsTstImmediate(masm->instr_at(pos)));

  }

  static void PatchNopIntoBranch(MacroAssembler* masm, int pos) {

    masm->instr_at_put(pos, (masm->instr_at(pos) & ~(B24 | B20)) | B27);

    ASSERT(Assembler::IsBranch(masm->instr_at(pos)));

  }

  static Mode GetMode(Code* stub) {

    Instr first_instruction = Assembler::instr_at(stub->instruction_start());

    Instr second_instruction = Assembler::instr_at(stub->instruction_start() +

                                                   Assembler::kInstrSize);

    if (Assembler::IsBranch(first_instruction)) {

      return INCREMENTAL;

    }

    ASSERT(Assembler::IsTstImmediate(first_instruction));

    if (Assembler::IsBranch(second_instruction)) {

      return INCREMENTAL_COMPACTION;

    }

    ASSERT(Assembler::IsTstImmediate(second_instruction));

    return STORE_BUFFER_ONLY;

  }

  static void Patch(Code* stub, Mode mode) {

    MacroAssembler masm(NULL,

                        stub->instruction_start(),

                        stub->instruction_size());

    switch (mode) {

      case STORE_BUFFER_ONLY:

        ASSERT(GetMode(stub) == INCREMENTAL ||

               GetMode(stub) == INCREMENTAL_COMPACTION);

        PatchBranchIntoNop(&masm, 0);

        PatchBranchIntoNop(&masm, Assembler::kInstrSize);

        break;

      case INCREMENTAL:

        ASSERT(GetMode(stub) == STORE_BUFFER_ONLY);

        PatchNopIntoBranch(&masm, 0);

        break;

      case INCREMENTAL_COMPACTION:

        ASSERT(GetMode(stub) == STORE_BUFFER_ONLY);

        PatchNopIntoBranch(&masm, Assembler::kInstrSize);

        break;

    }

    ASSERT(GetMode(stub) == mode);

    CPU::FlushICache(stub->instruction_start(), 2 * Assembler::kInstrSize);

  }

 private:

  // This is a helper class for freeing up 3 scratch registers.  The input is

  // two registers that must be preserved and one scratch register provided by

  // the caller.

  class RegisterAllocation {

   public:

    RegisterAllocation(Register object,

                       Register address,

                       Register scratch0)

        : object_(object),

          address_(address),

          scratch0_(scratch0) {

      ASSERT(!AreAliased(scratch0, object, address, no_reg));

      scratch1_ = GetRegisterThatIsNotOneOf(object_, address_, scratch0_);

    }

    void Save(MacroAssembler* masm) {

      ASSERT(!AreAliased(object_, address_, scratch1_, scratch0_));

      // We don't have to save scratch0_ because it was given to us as

      // a scratch register.

      masm->push(scratch1_);

    }

    void Restore(MacroAssembler* masm) {

      masm->pop(scratch1_);

    }

    // If we have to call into C then we need to save and restore all caller-

    // saved registers that were not already preserved.  The scratch registers

    // will be restored by other means so we don't bother pushing them here.

    void SaveCallerSaveRegisters(MacroAssembler* masm, SaveFPRegsMode mode) {

      masm->stm(db_w, sp, (kCallerSaved | lr.bit()) & ~scratch1_.bit());

      if (mode == kSaveFPRegs) {

        masm->SaveFPRegs(sp, scratch0_);

      }

    }

    inline void RestoreCallerSaveRegisters(MacroAssembler*masm,

                                           SaveFPRegsMode mode) {

      if (mode == kSaveFPRegs) {

        masm->RestoreFPRegs(sp, scratch0_);

      }

      masm->ldm(ia_w, sp, (kCallerSaved | lr.bit()) & ~scratch1_.bit());

    }

    inline Register object() { return object_; }

    inline Register address() { return address_; }

    inline Register scratch0() { return scratch0_; }

    inline Register scratch1() { return scratch1_; }

   private:

    Register object_;

    Register address_;

    Register scratch0_;

    Register scratch1_;

    friend class RecordWriteStub;

  };

  enum OnNoNeedToInformIncrementalMarker {

    kReturnOnNoNeedToInformIncrementalMarker,

    kUpdateRememberedSetOnNoNeedToInformIncrementalMarker

  };

  void Generate(MacroAssembler* masm);

  void GenerateIncremental(MacroAssembler* masm, Mode mode);

  void CheckNeedsToInformIncrementalMarker(

      MacroAssembler* masm,

      OnNoNeedToInformIncrementalMarker on_no_need,

      Mode mode);

  void InformIncrementalMarker(MacroAssembler* masm, Mode mode);

  Major MajorKey() { return RecordWrite; }

  int MinorKey() {

    return ObjectBits::encode(object_.code()) |

        ValueBits::encode(value_.code()) |

        AddressBits::encode(address_.code()) |

        RememberedSetActionBits::encode(remembered_set_action_) |

        SaveFPRegsModeBits::encode(save_fp_regs_mode_);

  }

  void Activate(Code* code) {

    code->GetHeap()->incremental_marking()->ActivateGeneratedStub(code);

  }

  class ObjectBits: public BitField<int, 0, 4> {};

  class ValueBits: public BitField<int, 4, 4> {};

  class AddressBits: public BitField<int, 8, 4> {};

  class RememberedSetActionBits: public BitField<RememberedSetAction, 12, 1> {};

  class SaveFPRegsModeBits: public BitField<SaveFPRegsMode, 13, 1> {};

  Register object_;

  Register value_;

  Register address_;

  RememberedSetAction remembered_set_action_;

  SaveFPRegsMode save_fp_regs_mode_;

  Label slow_;

  RegisterAllocation regs_;

};

// Trampoline stub to call into native code. To call safely into native code

// in the presence of compacting GC (which can move code objects) we need to

// keep the code which called into native pinned in the memory. Currently the

// simplest approach is to generate such stub early enough so it can never be

// moved by GC

class DirectCEntryStub: public PlatformCodeStub {

 public:

  DirectCEntryStub() {}

  void Generate(MacroAssembler* masm);

  void GenerateCall(MacroAssembler* masm, Register target);

 private:

  Major MajorKey() { return DirectCEntry; }

  int MinorKey() { return 0; }

  bool NeedsImmovableCode() { return true; }

};

class NameDictionaryLookupStub: public PlatformCodeStub {

 public:

  enum LookupMode { POSITIVE_LOOKUP, NEGATIVE_LOOKUP };

  explicit NameDictionaryLookupStub(LookupMode mode) : mode_(mode) { }

  void Generate(MacroAssembler* masm);

  static void GenerateNegativeLookup(MacroAssembler* masm,

                                     Label* miss,

                                     Label* done,

                                     Register receiver,

                                     Register properties,

                                     Handle<Name> name,

                                     Register scratch0);

  static void GeneratePositiveLookup(MacroAssembler* masm,

                                     Label* miss,

                                     Label* done,

                                     Register elements,

                                     Register name,

                                     Register r0,

                                     Register r1);

  virtual bool SometimesSetsUpAFrame() { return false; }

 private:

  static const int kInlinedProbes = 4;

  static const int kTotalProbes = 20;

  static const int kCapacityOffset =

      NameDictionary::kHeaderSize +

      NameDictionary::kCapacityIndex * kPointerSize;

  static const int kElementsStartOffset =

      NameDictionary::kHeaderSize +

      NameDictionary::kElementsStartIndex * kPointerSize;

  Major MajorKey() { return NameDictionaryLookup; }

  int MinorKey() {

    return LookupModeBits::encode(mode_);

  }

  class LookupModeBits: public BitField<LookupMode, 0, 1> {};

  LookupMode mode_;

};

} }  // namespace v8::internal

#endif  // V8_ARM_CODE_STUBS_ARM_H_