runtime/vm/instructions_arm64.h - sdk - Git at Google

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 // Classes that describe assembly patterns as used by inline caches.

 #ifndef RUNTIME_VM_INSTRUCTIONS_ARM64_H_
 #define RUNTIME_VM_INSTRUCTIONS_ARM64_H_

 #ifndef RUNTIME_VM_INSTRUCTIONS_H_
 #error Do not include instructions_arm64.h directly; use instructions.h instead.
 #endif

 #include "vm/allocation.h"
 #include "vm/constants.h"
 #include "vm/native_function.h"
 #include "vm/tagged_pointer.h"

 #if !defined(DART_PRECOMPILED_RUNTIME)
 #include "vm/compiler/assembler/assembler.h"
 #endif  // !defined(DART_PRECOMPILED_RUNTIME)

 namespace dart {

 class Code;
 class ICData;
 class Object;
 class ObjectPool;

 class InstructionPattern : public AllStatic {
  public:
   // Decodes a load sequence ending at 'end' (the last instruction of the
   // load sequence is the instruction before the one at end).  Returns the
   // address of the first instruction in the sequence.  Returns the register
   // being loaded and the loaded object in the output parameters 'reg' and
   // 'obj' respectively.
   static uword DecodeLoadObject(uword end,
                                 const ObjectPool& object_pool,
                                 Register* reg,
                                 Object* obj);

   // Decodes a load sequence ending at 'end' (the last instruction of the
   // load sequence is the instruction before the one at end).  Returns the
   // address of the first instruction in the sequence.  Returns the register
   // being loaded and the loaded immediate value in the output parameters
   // 'reg' and 'value' respectively.
   static uword DecodeLoadWordImmediate(uword end,
                                        Register* reg,
                                        intptr_t* value);

   // Decodes a load sequence ending at 'end' (the last instruction of the
   // load sequence is the instruction before the one at end).  Returns the
   // address of the first instruction in the sequence.  Returns the register
   // being loaded and the index in the pool being read from in the output
   // parameters 'reg' and 'index' respectively.
   // IMPORANT: When generating code loading values from pool on ARM64 use
   // LoadWordFromPool macro instruction instead of emitting direct load.
   // The macro instruction takes care of pool offsets that can't be
   // encoded as immediates.
   static uword DecodeLoadWordFromPool(uword end,
                                       Register* reg,
                                       intptr_t* index);

   // Decodes a load sequence ending at 'end' (the last instruction of the
   // load sequence is the instruction before the one at end).  Returns the
   // address of the first instruction in the sequence.  Returns the registers
   // being loaded and the index in the pool being read from in the output
   // parameters 'reg1', 'reg2' and 'index' respectively.
   // IMPORANT: When generating code loading values from pool on ARM64 use
   // LoadDoubleWordFromPool macro instruction instead of emitting direct load.
   // The macro instruction takes care of pool offsets that can't be
   // encoded as immediates.
   static uword DecodeLoadDoubleWordFromPool(uword end,
                                             Register* reg1,
                                             Register* reg2,
                                             intptr_t* index);

   // Encodes a load sequence ending at 'end'. Encodes a fixed length two
   // instruction load from the pool pointer in PP using the destination
   // register reg as a temporary for the base address.
   static void EncodeLoadWordFromPoolFixed(uword end, int32_t offset);
 };

 class CallPattern : public ValueObject {
  public:
   CallPattern(uword pc, const Code& code);

   CodePtr TargetCode() const;
   void SetTargetCode(const Code& target) const;

  private:
   const ObjectPool& object_pool_;

   intptr_t target_code_pool_index_;

   DISALLOW_COPY_AND_ASSIGN(CallPattern);
 };

 class ICCallPattern : public ValueObject {
  public:
   ICCallPattern(uword pc, const Code& caller_code);

   ObjectPtr Data() const;
   void SetData(const Object& data) const;

   CodePtr TargetCode() const;
   void SetTargetCode(const Code& target) const;

  private:
   const ObjectPool& object_pool_;

   intptr_t target_pool_index_;
   intptr_t data_pool_index_;

   DISALLOW_COPY_AND_ASSIGN(ICCallPattern);
 };

 class NativeCallPattern : public ValueObject {
  public:
   NativeCallPattern(uword pc, const Code& code);

   CodePtr target() const;
   void set_target(const Code& target) const;

   NativeFunction native_function() const;
   void set_native_function(NativeFunction target) const;

  private:
   const ObjectPool& object_pool_;

   uword end_;
   intptr_t native_function_pool_index_;
   intptr_t target_code_pool_index_;

   DISALLOW_COPY_AND_ASSIGN(NativeCallPattern);
 };

 // Instance call that can switch between a direct monomorphic call, an IC call,
 // and a megamorphic call.
 //   load guarded cid            load ICData             load MegamorphicCache
 //   load monomorphic target <-> load ICLookup stub  ->  load MMLookup stub
 //   call target.entry           call stub.entry         call stub.entry
 class SwitchableCallPatternBase : public ValueObject {
  public:
   explicit SwitchableCallPatternBase(const Code& code);

   ObjectPtr data() const;
   void SetData(const Object& data) const;

  protected:
   const ObjectPool& object_pool_;
   intptr_t data_pool_index_;
   intptr_t target_pool_index_;

  private:
   DISALLOW_COPY_AND_ASSIGN(SwitchableCallPatternBase);
 };

 // See [SwitchableCallBase] for a switchable calls in general.
 //
 // The target slot is always a [Code] object: Either the code of the
 // monomorphic function or a stub code.
 class SwitchableCallPattern : public SwitchableCallPatternBase {
  public:
   SwitchableCallPattern(uword pc, const Code& code);

   CodePtr target() const;
   void SetTarget(const Code& target) const;

  private:
   DISALLOW_COPY_AND_ASSIGN(SwitchableCallPattern);
 };

 // See [SwitchableCallBase] for a switchable calls in general.
 //
 // The target slot is always a direct entrypoint address: Either the entry point
 // of the monomorphic function or a stub entry point.
 class BareSwitchableCallPattern : public SwitchableCallPatternBase {
  public:
   BareSwitchableCallPattern(uword pc, const Code& code);

   CodePtr target() const;
   void SetTarget(const Code& target) const;

  private:
   DISALLOW_COPY_AND_ASSIGN(BareSwitchableCallPattern);
 };

 class ReturnPattern : public ValueObject {
  public:
   explicit ReturnPattern(uword pc);

   // bx_lr = 1.
   static const int kLengthInBytes = 1 * Instr::kInstrSize;

   int pattern_length_in_bytes() const { return kLengthInBytes; }

   bool IsValid() const;

  private:
   const uword pc_;
 };

 class PcRelativePatternBase : public ValueObject {
  public:
   // 26 bit signed integer which will get multiplied by 4.
   static const intptr_t kLowerCallingRange = -(1 << 27);
   static const intptr_t kUpperCallingRange = (1 << 27) - 1;

   explicit PcRelativePatternBase(uword pc) : pc_(pc) {}

   static const int kLengthInBytes = 1 * Instr::kInstrSize;

   int32_t distance() {
 #if !defined(DART_PRECOMPILED_RUNTIME)
     return compiler::Assembler::DecodeImm26BranchOffset(
         *reinterpret_cast<int32_t*>(pc_));
 #else
     UNREACHABLE();
     return 0;
 #endif
   }

   void set_distance(int32_t distance) {
 #if !defined(DART_PRECOMPILED_RUNTIME)
     int32_t* word = reinterpret_cast<int32_t*>(pc_);
     *word = compiler::Assembler::EncodeImm26BranchOffset(distance, *word);
 #else
     UNREACHABLE();
 #endif
   }

   bool IsValid() const;

  protected:
   uword pc_;
 };

 class PcRelativeCallPattern : public PcRelativePatternBase {
  public:
   explicit PcRelativeCallPattern(uword pc) : PcRelativePatternBase(pc) {}

   bool IsValid() const;
 };

 class PcRelativeTailCallPattern : public PcRelativePatternBase {
  public:
   explicit PcRelativeTailCallPattern(uword pc) : PcRelativePatternBase(pc) {}

   bool IsValid() const;
 };

 // Instruction pattern for a tail call to a signed 32-bit PC-relative offset
 //
 // The AOT compiler can emit PC-relative calls. If the destination of such a
 // call is not in range for the "bl <offset>" instruction, the AOT compiler will
 // emit a trampoline which is in range. That trampoline will then tail-call to
 // the final destination (also via PC-relative offset, but it supports a full
 // signed 32-bit offset).
 //
 // The pattern of the trampoline looks like:
 //
 //     adr TMP, #lower16  (same as TMP = PC + #lower16)
 //     movz TMP2, #higher16 lsl 16
 //     add TMP, TMP, TMP2, SXTW
 //     br TMP
 //
 class PcRelativeTrampolineJumpPattern : public ValueObject {
  public:
   explicit PcRelativeTrampolineJumpPattern(uword pattern_start)
       : pattern_start_(pattern_start) {
     USE(pattern_start_);
   }

   static const int kLengthInBytes = 4 * Instr::kInstrSize;

   void Initialize();

   int32_t distance();
   void set_distance(int32_t distance);
   bool IsValid() const;

  private:
   // This offset must be applied to account for the fact that
   //   a) the actual "branch" is only in the 3rd instruction
   //   b) when reading the PC it reports current instruction + 8
   static const intptr_t kDistanceOffset = -5 * Instr::kInstrSize;

   // adr TMP, #lower16  (same as TMP = PC + #lower16)
   static const uint32_t kAdrEncoding = (1 << 28) | (TMP << kRdShift);

   // movz TMP2, #higher16 lsl 16
   static const uint32_t kMovzEncoding = MOVZ | (1 << kHWShift) | TMP2;

   // add TMP, TMP, TMP2, SXTW
   static const uint32_t kAddTmpTmp2 = 0x8b31c210;

   // br TMP
   static const uint32_t kJumpEncoding = BR | (TMP << kRnShift);

   uword pattern_start_;
 };

 }  // namespace dart

 #endif  // RUNTIME_VM_INSTRUCTIONS_ARM64_H_
	// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
	// for details. All rights reserved. Use of this source code is governed by a
	// BSD-style license that can be found in the LICENSE file.
	// Classes that describe assembly patterns as used by inline caches.

	#ifndef RUNTIME_VM_INSTRUCTIONS_ARM64_H_
	#define RUNTIME_VM_INSTRUCTIONS_ARM64_H_

	#ifndef RUNTIME_VM_INSTRUCTIONS_H_
	#error Do not include instructions_arm64.h directly; use instructions.h instead.
	#endif

	#include "vm/allocation.h"
	#include "vm/constants.h"
	#include "vm/native_function.h"
	#include "vm/tagged_pointer.h"

	#if !defined(DART_PRECOMPILED_RUNTIME)
	#include "vm/compiler/assembler/assembler.h"
	#endif // !defined(DART_PRECOMPILED_RUNTIME)

	namespace dart {

	class Code;
	class ICData;
	class Object;
	class ObjectPool;

	class InstructionPattern : public AllStatic {
	public:
	// Decodes a load sequence ending at 'end' (the last instruction of the
	// load sequence is the instruction before the one at end). Returns the
	// address of the first instruction in the sequence. Returns the register
	// being loaded and the loaded object in the output parameters 'reg' and
	// 'obj' respectively.
	static uword DecodeLoadObject(uword end,
	const ObjectPool& object_pool,
	Register* reg,
	Object* obj);

	// Decodes a load sequence ending at 'end' (the last instruction of the
	// load sequence is the instruction before the one at end). Returns the
	// address of the first instruction in the sequence. Returns the register
	// being loaded and the loaded immediate value in the output parameters
	// 'reg' and 'value' respectively.
	static uword DecodeLoadWordImmediate(uword end,
	Register* reg,
	intptr_t* value);

	// Decodes a load sequence ending at 'end' (the last instruction of the
	// load sequence is the instruction before the one at end). Returns the
	// address of the first instruction in the sequence. Returns the register
	// being loaded and the index in the pool being read from in the output
	// parameters 'reg' and 'index' respectively.
	// IMPORANT: When generating code loading values from pool on ARM64 use
	// LoadWordFromPool macro instruction instead of emitting direct load.
	// The macro instruction takes care of pool offsets that can't be
	// encoded as immediates.
	static uword DecodeLoadWordFromPool(uword end,
	Register* reg,
	intptr_t* index);

	// Decodes a load sequence ending at 'end' (the last instruction of the
	// load sequence is the instruction before the one at end). Returns the
	// address of the first instruction in the sequence. Returns the registers
	// being loaded and the index in the pool being read from in the output
	// parameters 'reg1', 'reg2' and 'index' respectively.
	// IMPORANT: When generating code loading values from pool on ARM64 use
	// LoadDoubleWordFromPool macro instruction instead of emitting direct load.
	// The macro instruction takes care of pool offsets that can't be
	// encoded as immediates.
	static uword DecodeLoadDoubleWordFromPool(uword end,
	Register* reg1,
	Register* reg2,
	intptr_t* index);

	// Encodes a load sequence ending at 'end'. Encodes a fixed length two
	// instruction load from the pool pointer in PP using the destination
	// register reg as a temporary for the base address.
	static void EncodeLoadWordFromPoolFixed(uword end, int32_t offset);
	};

	class CallPattern : public ValueObject {
	public:
	CallPattern(uword pc, const Code& code);

	CodePtr TargetCode() const;
	void SetTargetCode(const Code& target) const;

	private:
	const ObjectPool& object_pool_;

	intptr_t target_code_pool_index_;

	DISALLOW_COPY_AND_ASSIGN(CallPattern);
	};

	class ICCallPattern : public ValueObject {
	public:
	ICCallPattern(uword pc, const Code& caller_code);

	ObjectPtr Data() const;
	void SetData(const Object& data) const;

	CodePtr TargetCode() const;
	void SetTargetCode(const Code& target) const;

	private:
	const ObjectPool& object_pool_;

	intptr_t target_pool_index_;
	intptr_t data_pool_index_;

	DISALLOW_COPY_AND_ASSIGN(ICCallPattern);
	};

	class NativeCallPattern : public ValueObject {
	public:
	NativeCallPattern(uword pc, const Code& code);

	CodePtr target() const;
	void set_target(const Code& target) const;

	NativeFunction native_function() const;
	void set_native_function(NativeFunction target) const;

	private:
	const ObjectPool& object_pool_;

	uword end_;
	intptr_t native_function_pool_index_;
	intptr_t target_code_pool_index_;

	DISALLOW_COPY_AND_ASSIGN(NativeCallPattern);
	};

	// Instance call that can switch between a direct monomorphic call, an IC call,
	// and a megamorphic call.
	// load guarded cid load ICData load MegamorphicCache
	// load monomorphic target <-> load ICLookup stub -> load MMLookup stub
	// call target.entry call stub.entry call stub.entry
	class SwitchableCallPatternBase : public ValueObject {
	public:
	explicit SwitchableCallPatternBase(const Code& code);

	ObjectPtr data() const;
	void SetData(const Object& data) const;

	protected:
	const ObjectPool& object_pool_;
	intptr_t data_pool_index_;
	intptr_t target_pool_index_;

	private:
	DISALLOW_COPY_AND_ASSIGN(SwitchableCallPatternBase);
	};

	// See [SwitchableCallBase] for a switchable calls in general.
	//
	// The target slot is always a [Code] object: Either the code of the
	// monomorphic function or a stub code.
	class SwitchableCallPattern : public SwitchableCallPatternBase {
	public:
	SwitchableCallPattern(uword pc, const Code& code);

	CodePtr target() const;
	void SetTarget(const Code& target) const;

	private:
	DISALLOW_COPY_AND_ASSIGN(SwitchableCallPattern);
	};

	// See [SwitchableCallBase] for a switchable calls in general.
	//
	// The target slot is always a direct entrypoint address: Either the entry point
	// of the monomorphic function or a stub entry point.
	class BareSwitchableCallPattern : public SwitchableCallPatternBase {
	public:
	BareSwitchableCallPattern(uword pc, const Code& code);

	CodePtr target() const;
	void SetTarget(const Code& target) const;

	private:
	DISALLOW_COPY_AND_ASSIGN(BareSwitchableCallPattern);
	};

	class ReturnPattern : public ValueObject {
	public:
	explicit ReturnPattern(uword pc);

	// bx_lr = 1.
	static const int kLengthInBytes = 1 * Instr::kInstrSize;

	int pattern_length_in_bytes() const { return kLengthInBytes; }

	bool IsValid() const;

	private:
	const uword pc_;
	};

	class PcRelativePatternBase : public ValueObject {
	public:
	// 26 bit signed integer which will get multiplied by 4.
	static const intptr_t kLowerCallingRange = -(1 << 27);
	static const intptr_t kUpperCallingRange = (1 << 27) - 1;

	explicit PcRelativePatternBase(uword pc) : pc_(pc) {}

	static const int kLengthInBytes = 1 * Instr::kInstrSize;

	int32_t distance() {
	#if !defined(DART_PRECOMPILED_RUNTIME)
	return compiler::Assembler::DecodeImm26BranchOffset(
	reinterpret_cast<int32_t>(pc_));
	#else
	UNREACHABLE();
	return 0;
	#endif
	}

	void set_distance(int32_t distance) {
	#if !defined(DART_PRECOMPILED_RUNTIME)
	int32_t* word = reinterpret_cast<int32_t*>(pc_);
	word = compiler::Assembler::EncodeImm26BranchOffset(distance, word);
	#else
	UNREACHABLE();
	#endif
	}

	bool IsValid() const;

	protected:
	uword pc_;
	};

	class PcRelativeCallPattern : public PcRelativePatternBase {
	public:
	explicit PcRelativeCallPattern(uword pc) : PcRelativePatternBase(pc) {}

	bool IsValid() const;
	};

	class PcRelativeTailCallPattern : public PcRelativePatternBase {
	public:
	explicit PcRelativeTailCallPattern(uword pc) : PcRelativePatternBase(pc) {}

	bool IsValid() const;
	};

	// Instruction pattern for a tail call to a signed 32-bit PC-relative offset
	//
	// The AOT compiler can emit PC-relative calls. If the destination of such a
	// call is not in range for the "bl <offset>" instruction, the AOT compiler will
	// emit a trampoline which is in range. That trampoline will then tail-call to
	// the final destination (also via PC-relative offset, but it supports a full
	// signed 32-bit offset).
	//
	// The pattern of the trampoline looks like:
	//
	// adr TMP, #lower16 (same as TMP = PC + #lower16)
	// movz TMP2, #higher16 lsl 16
	// add TMP, TMP, TMP2, SXTW
	// br TMP
	//
	class PcRelativeTrampolineJumpPattern : public ValueObject {
	public:
	explicit PcRelativeTrampolineJumpPattern(uword pattern_start)
	: pattern_start_(pattern_start) {
	USE(pattern_start_);
	}

	static const int kLengthInBytes = 4 * Instr::kInstrSize;

	void Initialize();

	int32_t distance();
	void set_distance(int32_t distance);
	bool IsValid() const;

	private:
	// This offset must be applied to account for the fact that
	// a) the actual "branch" is only in the 3rd instruction
	// b) when reading the PC it reports current instruction + 8
	static const intptr_t kDistanceOffset = -5 * Instr::kInstrSize;

	// adr TMP, #lower16 (same as TMP = PC + #lower16)
	static const uint32_t kAdrEncoding = (1 << 28) \| (TMP << kRdShift);

	// movz TMP2, #higher16 lsl 16
	static const uint32_t kMovzEncoding = MOVZ \| (1 << kHWShift) \| TMP2;

	// add TMP, TMP, TMP2, SXTW
	static const uint32_t kAddTmpTmp2 = 0x8b31c210;

	// br TMP
	static const uint32_t kJumpEncoding = BR \| (TMP << kRnShift);

	uword pattern_start_;
	};

	} // namespace dart

	#endif // RUNTIME_VM_INSTRUCTIONS_ARM64_H_