src/arm/code-stubs-arm.h - external/v8 - Git at Google

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #ifndef V8_ARM_CODE_STUBS_ARM_H_
 #define V8_ARM_CODE_STUBS_ARM_H_

 namespace v8 {
 namespace internal {


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


 class StringHelper : public AllStatic {
  public:
   // 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 GenerateCopyCharacters(MacroAssembler* masm,
                                      Register dest,
                                      Register src,
                                      Register count,
                                      Register scratch,
                                      String::Encoding encoding);

   // Compares two flat one-byte strings and returns result in r0.
   static void GenerateCompareFlatOneByteStrings(
       MacroAssembler* masm, Register left, Register right, Register scratch1,
       Register scratch2, Register scratch3, Register scratch4);

   // Compares two flat one-byte strings for equality and returns result in r0.
   static void GenerateFlatOneByteStringEquals(MacroAssembler* masm,
                                               Register left, Register right,
                                               Register scratch1,
                                               Register scratch2,
                                               Register scratch3);

  private:
   static void GenerateOneByteCharsCompareLoop(
       MacroAssembler* masm, Register left, Register right, Register length,
       Register scratch1, Register scratch2, Label* chars_not_equal);

   DISALLOW_IMPLICIT_CONSTRUCTORS(StringHelper);
 };


 class RecordWriteStub: public PlatformCodeStub {
  public:
   RecordWriteStub(Isolate* isolate,
                   Register object,
                   Register value,
                   Register address,
                   RememberedSetAction remembered_set_action,
                   SaveFPRegsMode fp_mode)
       : PlatformCodeStub(isolate),
         regs_(object,   // An input reg.
               address,  // An input reg.
               value) {  // One scratch reg.
     minor_key_ = ObjectBits::encode(object.code()) |
                  ValueBits::encode(value.code()) |
                  AddressBits::encode(address.code()) |
                  RememberedSetActionBits::encode(remembered_set_action) |
                  SaveFPRegsModeBits::encode(fp_mode);
   }

   RecordWriteStub(uint32_t key, Isolate* isolate)
       : PlatformCodeStub(key, isolate), regs_(object(), address(), value()) {}

   enum Mode {
     STORE_BUFFER_ONLY,
     INCREMENTAL,
     INCREMENTAL_COMPACTION
   };

   virtual bool SometimesSetsUpAFrame() { return false; }

   static void PatchBranchIntoNop(MacroAssembler* masm, int pos) {
     masm->instr_at_put(pos, (masm->instr_at(pos) & ~B27) | (B24 | B20));
     DCHECK(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);
     DCHECK(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;
     }

     DCHECK(Assembler::IsTstImmediate(first_instruction));

     if (Assembler::IsBranch(second_instruction)) {
       return INCREMENTAL_COMPACTION;
     }

     DCHECK(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:
         DCHECK(GetMode(stub) == INCREMENTAL ||
                GetMode(stub) == INCREMENTAL_COMPACTION);
         PatchBranchIntoNop(&masm, 0);
         PatchBranchIntoNop(&masm, Assembler::kInstrSize);
         break;
       case INCREMENTAL:
         DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
         PatchNopIntoBranch(&masm, 0);
         break;
       case INCREMENTAL_COMPACTION:
         DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
         PatchNopIntoBranch(&masm, Assembler::kInstrSize);
         break;
     }
     DCHECK(GetMode(stub) == mode);
     CpuFeatures::FlushICache(stub->instruction_start(),
                              2 * Assembler::kInstrSize);
   }

   DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();

  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) {
       DCHECK(!AreAliased(scratch0, object, address, no_reg));
       scratch1_ = GetRegisterThatIsNotOneOf(object_, address_, scratch0_);
     }

     void Save(MacroAssembler* masm) {
       DCHECK(!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
   };

   virtual inline Major MajorKey() const FINAL OVERRIDE { return RecordWrite; }

   virtual void Generate(MacroAssembler* masm) OVERRIDE;
   void GenerateIncremental(MacroAssembler* masm, Mode mode);
   void CheckNeedsToInformIncrementalMarker(
       MacroAssembler* masm,
       OnNoNeedToInformIncrementalMarker on_no_need,
       Mode mode);
   void InformIncrementalMarker(MacroAssembler* masm);

   void Activate(Code* code) {
     code->GetHeap()->incremental_marking()->ActivateGeneratedStub(code);
   }

   Register object() const {
     return Register::from_code(ObjectBits::decode(minor_key_));
   }

   Register value() const {
     return Register::from_code(ValueBits::decode(minor_key_));
   }

   Register address() const {
     return Register::from_code(AddressBits::decode(minor_key_));
   }

   RememberedSetAction remembered_set_action() const {
     return RememberedSetActionBits::decode(minor_key_);
   }

   SaveFPRegsMode save_fp_regs_mode() const {
     return SaveFPRegsModeBits::decode(minor_key_);
   }

   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> {};

   Label slow_;
   RegisterAllocation regs_;

   DISALLOW_COPY_AND_ASSIGN(RecordWriteStub);
 };


 // 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:
   explicit DirectCEntryStub(Isolate* isolate) : PlatformCodeStub(isolate) {}
   void GenerateCall(MacroAssembler* masm, Register target);

  private:
   bool NeedsImmovableCode() { return true; }

   DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
   DEFINE_PLATFORM_CODE_STUB(DirectCEntry, PlatformCodeStub);
 };


 class NameDictionaryLookupStub: public PlatformCodeStub {
  public:
   enum LookupMode { POSITIVE_LOOKUP, NEGATIVE_LOOKUP };

   NameDictionaryLookupStub(Isolate* isolate, LookupMode mode)
       : PlatformCodeStub(isolate) {
     minor_key_ = LookupModeBits::encode(mode);
   }

   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;

   LookupMode mode() const { return LookupModeBits::decode(minor_key_); }

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

   DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
   DEFINE_PLATFORM_CODE_STUB(NameDictionaryLookup, PlatformCodeStub);
 };

 } }  // namespace v8::internal

 #endif  // V8_ARM_CODE_STUBS_ARM_H_
	// Copyright 2012 the V8 project authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#ifndef V8_ARM_CODE_STUBS_ARM_H_
	#define V8_ARM_CODE_STUBS_ARM_H_

	namespace v8 {
	namespace internal {


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


	class StringHelper : public AllStatic {
	public:
	// 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 GenerateCopyCharacters(MacroAssembler* masm,
	Register dest,
	Register src,
	Register count,
	Register scratch,
	String::Encoding encoding);

	// Compares two flat one-byte strings and returns result in r0.
	static void GenerateCompareFlatOneByteStrings(
	MacroAssembler* masm, Register left, Register right, Register scratch1,
	Register scratch2, Register scratch3, Register scratch4);

	// Compares two flat one-byte strings for equality and returns result in r0.
	static void GenerateFlatOneByteStringEquals(MacroAssembler* masm,
	Register left, Register right,
	Register scratch1,
	Register scratch2,
	Register scratch3);

	private:
	static void GenerateOneByteCharsCompareLoop(
	MacroAssembler* masm, Register left, Register right, Register length,
	Register scratch1, Register scratch2, Label* chars_not_equal);

	DISALLOW_IMPLICIT_CONSTRUCTORS(StringHelper);
	};


	class RecordWriteStub: public PlatformCodeStub {
	public:
	RecordWriteStub(Isolate* isolate,
	Register object,
	Register value,
	Register address,
	RememberedSetAction remembered_set_action,
	SaveFPRegsMode fp_mode)
	: PlatformCodeStub(isolate),
	regs_(object, // An input reg.
	address, // An input reg.
	value) { // One scratch reg.
	minor_key_ = ObjectBits::encode(object.code()) \|
	ValueBits::encode(value.code()) \|
	AddressBits::encode(address.code()) \|
	RememberedSetActionBits::encode(remembered_set_action) \|
	SaveFPRegsModeBits::encode(fp_mode);
	}

	RecordWriteStub(uint32_t key, Isolate* isolate)
	: PlatformCodeStub(key, isolate), regs_(object(), address(), value()) {}

	enum Mode {
	STORE_BUFFER_ONLY,
	INCREMENTAL,
	INCREMENTAL_COMPACTION
	};

	virtual bool SometimesSetsUpAFrame() { return false; }

	static void PatchBranchIntoNop(MacroAssembler* masm, int pos) {
	masm->instr_at_put(pos, (masm->instr_at(pos) & ~B27) \| (B24 \| B20));
	DCHECK(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);
	DCHECK(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;
	}

	DCHECK(Assembler::IsTstImmediate(first_instruction));

	if (Assembler::IsBranch(second_instruction)) {
	return INCREMENTAL_COMPACTION;
	}

	DCHECK(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:
	DCHECK(GetMode(stub) == INCREMENTAL \|\|
	GetMode(stub) == INCREMENTAL_COMPACTION);
	PatchBranchIntoNop(&masm, 0);
	PatchBranchIntoNop(&masm, Assembler::kInstrSize);
	break;
	case INCREMENTAL:
	DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
	PatchNopIntoBranch(&masm, 0);
	break;
	case INCREMENTAL_COMPACTION:
	DCHECK(GetMode(stub) == STORE_BUFFER_ONLY);
	PatchNopIntoBranch(&masm, Assembler::kInstrSize);
	break;
	}
	DCHECK(GetMode(stub) == mode);
	CpuFeatures::FlushICache(stub->instruction_start(),
	2 * Assembler::kInstrSize);
	}

	DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();

	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) {
	DCHECK(!AreAliased(scratch0, object, address, no_reg));
	scratch1_ = GetRegisterThatIsNotOneOf(object_, address_, scratch0_);
	}

	void Save(MacroAssembler* masm) {
	DCHECK(!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
	};

	virtual inline Major MajorKey() const FINAL OVERRIDE { return RecordWrite; }

	virtual void Generate(MacroAssembler* masm) OVERRIDE;
	void GenerateIncremental(MacroAssembler* masm, Mode mode);
	void CheckNeedsToInformIncrementalMarker(
	MacroAssembler* masm,
	OnNoNeedToInformIncrementalMarker on_no_need,
	Mode mode);
	void InformIncrementalMarker(MacroAssembler* masm);

	void Activate(Code* code) {
	code->GetHeap()->incremental_marking()->ActivateGeneratedStub(code);
	}

	Register object() const {
	return Register::from_code(ObjectBits::decode(minor_key_));
	}

	Register value() const {
	return Register::from_code(ValueBits::decode(minor_key_));
	}

	Register address() const {
	return Register::from_code(AddressBits::decode(minor_key_));
	}

	RememberedSetAction remembered_set_action() const {
	return RememberedSetActionBits::decode(minor_key_);
	}

	SaveFPRegsMode save_fp_regs_mode() const {
	return SaveFPRegsModeBits::decode(minor_key_);
	}

	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> {};

	Label slow_;
	RegisterAllocation regs_;

	DISALLOW_COPY_AND_ASSIGN(RecordWriteStub);
	};


	// 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:
	explicit DirectCEntryStub(Isolate* isolate) : PlatformCodeStub(isolate) {}
	void GenerateCall(MacroAssembler* masm, Register target);

	private:
	bool NeedsImmovableCode() { return true; }

	DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
	DEFINE_PLATFORM_CODE_STUB(DirectCEntry, PlatformCodeStub);
	};


	class NameDictionaryLookupStub: public PlatformCodeStub {
	public:
	enum LookupMode { POSITIVE_LOOKUP, NEGATIVE_LOOKUP };

	NameDictionaryLookupStub(Isolate* isolate, LookupMode mode)
	: PlatformCodeStub(isolate) {
	minor_key_ = LookupModeBits::encode(mode);
	}

	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;

	LookupMode mode() const { return LookupModeBits::decode(minor_key_); }

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

	DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
	DEFINE_PLATFORM_CODE_STUB(NameDictionaryLookup, PlatformCodeStub);
	};

	} } // namespace v8::internal

	#endif // V8_ARM_CODE_STUBS_ARM_H_