MIPS port initial commit

src/mips/assembler-mips.h

Index: src/mips/assembler-mips.h
===================================================================
--- src/mips/assembler-mips.h	(revision 0)
+++ src/mips/assembler-mips.h	(revision 0)
@@ -0,0 +1,663 @@
+// Copyright (c) 1994-2006 Sun Microsystems Inc.
+// 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.
+//
+// - Redistribution 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 Sun Microsystems or the names of 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.
+
+// The original source code covered by the above license above has been
+// modified significantly by Google Inc.
+// Copyright 2010 the V8 project authors. All rights reserved.
+
+
+#ifndef V8_MIPS_ASSEMBLER_MIPS_H_
+#define V8_MIPS_ASSEMBLER_MIPS_H_
+
+#include <stdio.h>
+#include "assembler.h"
+#include "constants-mips.h"
+#include "serialize.h"
+
+using namespace assembler::mips;
+
+namespace v8 {
+namespace internal {
+
+// CPU Registers.
+//
+// 1) We would prefer to use an enum, but enum values are assignment-
+// compatible with int, which has caused code-generation bugs.
+//
+// 2) We would prefer to use a class instead of a struct but we don't like
+// the register initialization to depend on the particular initialization
+// order (which appears to be different on OS X, Linux, and Windows for the
+// installed versions of C++ we tried). Using a struct permits C-style
+// "initialization". Also, the Register objects cannot be const as this
+// forces initialization stubs in MSVC, making us dependent on initialization
+// order.
+//
+// 3) By not using an enum, we are possibly preventing the compiler from
+// doing certain constant folds, which may significantly reduce the
+// code generated for some assembly instructions (because they boil down
+// to a few constants). If this is a problem, we could change the code
+// such that we use an enum in optimized mode, and the struct in debug
+// mode. This way we get the compile-time error checking in debug mode
+// and best performance in optimized code.
+
+
+// -----------------------------------------------------------------------------
+// Implementation of Register and FPURegister
+
+// Core register.
+struct Register {
+  bool is_valid() const  { return 0 <= code_ && code_ < kNumRegisters; }
+  bool is(Register reg) const  { return code_ == reg.code_; }
+  int code() const  {
+    ASSERT(is_valid());
+    return code_;
+  }
+  int bit() const  {
+    ASSERT(is_valid());
+    return 1 << code_;
+  }
+
+  // Unfortunately we can't make this private in a struct.
+  int code_;
+};
+
+extern const Register no_reg;
+
+extern const Register zero_reg;
+extern const Register at;
+extern const Register v0;
+extern const Register v1;
+extern const Register a0;
+extern const Register a1;
+extern const Register a2;
+extern const Register a3;
+extern const Register t0;
+extern const Register t1;
+extern const Register t2;
+extern const Register t3;
+extern const Register t4;
+extern const Register t5;
+extern const Register t6;
+extern const Register t7;
+extern const Register s0;
+extern const Register s1;
+extern const Register s2;
+extern const Register s3;
+extern const Register s4;
+extern const Register s5;
+extern const Register s6;
+extern const Register s7;
+extern const Register t8;
+extern const Register t9;
+extern const Register k0;
+extern const Register k1;
+extern const Register gp;
+extern const Register sp;
+extern const Register s8_fp;
+extern const Register ra;
+
+int ToNumber(Register reg);
+
+Register ToRegister(int num);
+
+// Coprocessor register.
+struct FPURegister {
+  bool is_valid() const  { return 0 <= code_ && code_ < kNumFPURegister ; }
+  bool is(FPURegister creg) const  { return code_ == creg.code_; }
+  int code() const  {
+    ASSERT(is_valid());
+    return code_;
+  }
+  int bit() const  {
+    ASSERT(is_valid());
+    return 1 << code_;
+  }
+
+  // Unfortunately we can't make this private in a struct.
+  int code_;
+};
+
+extern const FPURegister no_creg;
+
+extern const FPURegister f0;
+extern const FPURegister f1;
+extern const FPURegister f2;
+extern const FPURegister f3;
+extern const FPURegister f4;
+extern const FPURegister f5;
+extern const FPURegister f6;
+extern const FPURegister f7;
+extern const FPURegister f8;
+extern const FPURegister f9;
+extern const FPURegister f10;
+extern const FPURegister f11;
+extern const FPURegister f12;  // arg
+extern const FPURegister f13;
+extern const FPURegister f14;  // arg
+extern const FPURegister f15;
+extern const FPURegister f16;
+extern const FPURegister f17;
+extern const FPURegister f18;
+extern const FPURegister f19;
+extern const FPURegister f20;
+extern const FPURegister f21;
+extern const FPURegister f22;
+extern const FPURegister f23;
+extern const FPURegister f24;
+extern const FPURegister f25;
+extern const FPURegister f26;
+extern const FPURegister f27;
+extern const FPURegister f28;
+extern const FPURegister f29;
+extern const FPURegister f30;
+extern const FPURegister f31;
+
+
+// Returns the equivalent of !cc.
+// Negation of the default no_condition (-1) results in a non-default
+// no_condition value (-2). As long as tests for no_condition check
+// for condition < 0, this will work as expected.
+inline Condition NegateCondition(Condition cc);
+
+inline Condition ReverseCondition(Condition cc) {
+  switch (cc) {
+    case Uless:
+      return Ugreater;
+    case Ugreater:
+      return Uless;
+    case Ugreater_equal:
+      return Uless_equal;
+    case Uless_equal:
+      return Ugreater_equal;
+    case less:
+      return greater;
+    case greater:
+      return less;
+    case greater_equal:
+      return less_equal;
+    case less_equal:
+      return greater_equal;
+    default:
+      return cc;
+  };
+}
+
+
+enum Hint {
+  no_hint = 0
+};
+
+inline Hint NegateHint(Hint hint) {
+  return no_hint;
+}
+
+
+// -----------------------------------------------------------------------------
+// Machine instruction Operands.
+
+// Class Operand represents a shifter operand in data processing instructions.
+class Operand BASE_EMBEDDED {
+ public:
+  // Immediate.
+  INLINE(explicit Operand(int32_t immediate,
+         RelocInfo::Mode rmode = RelocInfo::NONE));
+  INLINE(explicit Operand(const ExternalReference& f));
+  INLINE(explicit Operand(const char* s));
+  INLINE(explicit Operand(Object** opp));
+  INLINE(explicit Operand(Context** cpp));
+  explicit Operand(Handle<Object> handle);
+  INLINE(explicit Operand(Smi* value));
+
+  // Register.
+  INLINE(explicit Operand(Register rm));
+
+  // Return true if this is a register operand.
+  INLINE(bool is_reg() const);
+
+  Register rm() const { return rm_; }
+
+ private:
+  Register rm_;
+  int32_t imm32_;  // Valid if rm_ == no_reg
+  RelocInfo::Mode rmode_;
+
+  friend class Assembler;
+  friend class MacroAssembler;
+};
+
+
+// On MIPS we have only one adressing mode with base_reg + offset.
+// Class MemOperand represents a memory operand in load and store instructions.
+class MemOperand : public Operand {
+ public:
+
+  explicit MemOperand(Register rn, int16_t offset = 0);
+
+ private:
+  int16_t offset_;
+
+  friend class Assembler;
+};
+
+
+class Assembler : public Malloced {
+ public:
+  // Create an assembler. Instructions and relocation information are emitted
+  // into a buffer, with the instructions starting from the beginning and the
+  // relocation information starting from the end of the buffer. See CodeDesc
+  // for a detailed comment on the layout (globals.h).
+  //
+  // If the provided buffer is NULL, the assembler allocates and grows its own
+  // buffer, and buffer_size determines the initial buffer size. The buffer is
+  // owned by the assembler and deallocated upon destruction of the assembler.
+  //
+  // If the provided buffer is not NULL, the assembler uses the provided buffer
+  // for code generation and assumes its size to be buffer_size. If the buffer
+  // is too small, a fatal error occurs. No deallocation of the buffer is done
+  // upon destruction of the assembler.
+  Assembler(void* buffer, int buffer_size);
+  ~Assembler();
+
+  // GetCode emits any pending (non-emitted) code and fills the descriptor
+  // desc. GetCode() is idempotent; it returns the same result if no other
+  // Assembler functions are invoked in between GetCode() calls.
+  void GetCode(CodeDesc* desc);
+
+  // Label operations & relative jumps (PPUM Appendix D).
+  //
+  // Takes a branch opcode (cc) and a label (L) and generates
+  // either a backward branch or a forward branch and links it
+  // to the label fixup chain. Usage:
+  //
+  // Label L;    // unbound label
+  // j(cc, &L);  // forward branch to unbound label
+  // bind(&L);   // bind label to the current pc
+  // j(cc, &L);  // backward branch to bound label
+  // bind(&L);   // illegal: a label may be bound only once
+  //
+  // Note: The same Label can be used for forward and backward branches
+  // but it may be bound only once.
+  void bind(Label* L);  // binds an unbound label L to the current code position
+
+  // Returns the branch offset to the given label from the current code position
+  // Links the label to the current position if it is still unbound
+  // Manages the jump elimination optimization if the second parameter is true.
+  int32_t branch_offset(Label* L, bool jump_elimination_allowed);
+  int32_t shifted_branch_offset(Label* L, bool jump_elimination_allowed) {
+    int32_t o = branch_offset(L, jump_elimination_allowed);
+    ASSERT((o & 3) == 0);   // Assert the offset is aligned.
+    return o >> 2;
+  }
+
+  // Puts a labels target address at the given position.
+  // The high 8 bits are set to zero.
+  void label_at_put(Label* L, int at_offset);
+
+  // Size of an instruction.
+  static const int kInstrSize = sizeof(Instr);
+
+  // Difference between address of current opcode and target address offset.
+  static const int kBranchPCOffset = 4;
+
+  // Read/Modify the code target address in the branch/call instruction at pc.
+  static Address target_address_at(Address pc);
+  static void set_target_address_at(Address pc, Address target);
+
+  // This sets the branch destination (which gets loaded at the call address).
+  // This is for calls and branches within generated code.
+  inline static void set_target_at(Address instruction_payload,
+                                   Address target) {
+    set_target_address_at(instruction_payload, target);
+  }
+
+  // This sets the branch destination.
+  // This is for calls and branches to runtime code.
+  inline static void set_external_target_at(Address instruction_payload,
+                                            Address target) {
+    set_target_address_at(instruction_payload, target);
+  }
+
+  static const int kCallTargetSize = 3 * kPointerSize;
+  static const int kExternalTargetSize = 3 * kPointerSize;
+
+  // Distance between the instruction referring to the address of the call
+  // target and the return address.
+  static const int kCallTargetAddressOffset = 4 * kInstrSize;
+
+  // Distance between start of patched return sequence and the emitted address
+  // to jump to.
+  static const int kPatchReturnSequenceAddressOffset = kInstrSize;
+
+
+  // ---------------------------------------------------------------------------
+  // Code generation.
+
+  void nop() { sll(zero_reg, zero_reg, 0); }
+
+
+  //------- Branch and jump  instructions --------
+  // We don't use likely variant of instructions.
+  void b(int16_t offset);
+  void b(Label* L) { b(branch_offset(L, false)>>2); }
+  void bal(int16_t offset);
+  void bal(Label* L) { bal(branch_offset(L, false)>>2); }
+
+  void beq(Register rs, Register rt, int16_t offset);
+  void beq(Register rs, Register rt, Label* L) {
+    beq(rs, rt, branch_offset(L, false) >> 2);
+  }
+  void bgez(Register rs, int16_t offset);
+  void bgezal(Register rs, int16_t offset);
+  void bgtz(Register rs, int16_t offset);
+  void blez(Register rs, int16_t offset);
+  void bltz(Register rs, int16_t offset);
+  void bltzal(Register rs, int16_t offset);
+  void bne(Register rs, Register rt, int16_t offset);
+  void bne(Register rs, Register rt, Label* L) {
+    bne(rs, rt, branch_offset(L, false)>>2);
+  }
+
+  // Never use the int16_t b(l)cond version with a branch offset
+  // instead of using the Label* version. See Twiki for infos.
+
+  // Jump targets must be in the current 256 MB-aligned region. ie 28 bits.
+  void j(int32_t target);
+  void jal(int32_t target);
+  void jalr(Register rs, Register rd = ra);
+  void jr(Register target);
+
+
+  //-------Data-processing-instructions---------
+
+  // Arithmetic.
+  void add(Register rd, Register rs, Register rt);
+  void addu(Register rd, Register rs, Register rt);
+  void sub(Register rd, Register rs, Register rt);
+  void subu(Register rd, Register rs, Register rt);
+  void mult(Register rs, Register rt);
+  void multu(Register rs, Register rt);
+  void div(Register rs, Register rt);
+  void divu(Register rs, Register rt);
+  void mul(Register rd, Register rs, Register rt);
+
+  void addi(Register rd, Register rs, int32_t j);
+  void addiu(Register rd, Register rs, int32_t j);
+
+  // Logical.
+  void and_(Register rd, Register rs, Register rt);
+  void or_(Register rd, Register rs, Register rt);
+  void xor_(Register rd, Register rs, Register rt);
+  void nor(Register rd, Register rs, Register rt);
+
+  void andi(Register rd, Register rs, int32_t j);
+  void ori(Register rd, Register rs, int32_t j);
+  void xori(Register rd, Register rs, int32_t j);
+  void lui(Register rd, int32_t j);
+
+  // Shifts.
+  void sll(Register rd, Register rt, uint16_t sa);
+  void sllv(Register rd, Register rt, Register rs);
+  void srl(Register rd, Register rt, uint16_t sa);
+  void srlv(Register rd, Register rt, Register rs);
+  void sra(Register rt, Register rd, uint16_t sa);
+  void srav(Register rt, Register rd, Register rs);
+
+
+  //------------Memory-instructions-------------
+
+  void lb(Register rd, const MemOperand& rs);
+  void lbu(Register rd, const MemOperand& rs);
+  void lw(Register rd, const MemOperand& rs);
+  void sb(Register rd, const MemOperand& rs);
+  void sw(Register rd, const MemOperand& rs);
+
+
+  //-------------Misc-instructions--------------
+
+  // Break / Trap instructions.
+  void break_(uint32_t code);
+  void tge(Register rs, Register rt, uint16_t code);
+  void tgeu(Register rs, Register rt, uint16_t code);
+  void tlt(Register rs, Register rt, uint16_t code);
+  void tltu(Register rs, Register rt, uint16_t code);
+  void teq(Register rs, Register rt, uint16_t code);
+  void tne(Register rs, Register rt, uint16_t code);
+
+  // Move from HI/LO register.
+  void mfhi(Register rd);
+  void mflo(Register rd);
+
+  // Set on less than.
+  void slt(Register rd, Register rs, Register rt);
+  void sltu(Register rd, Register rs, Register rt);
+  void slti(Register rd, Register rs, int32_t j);
+  void sltiu(Register rd, Register rs, int32_t j);
+
+
+  //--------Coprocessor-instructions----------------
+
+  // Load, store, and move.
+  void lwc1(FPURegister fd, const MemOperand& src);
+  void ldc1(FPURegister fd, const MemOperand& src);
+
+  void swc1(FPURegister fs, const MemOperand& dst);
+  void sdc1(FPURegister fs, const MemOperand& dst);
+
+  // When paired with MTC1 to write a value to a 64-bit FPR, the MTC1 must be
+  // executed first, followed by the MTHC1.
+  void mtc1(FPURegister fs, Register rt);
+  void mthc1(FPURegister fs, Register rt);
+  void mfc1(FPURegister fs, Register rt);
+  void mfhc1(FPURegister fs, Register rt);
+
+  // Conversion.
+  void cvt_w_s(FPURegister fd, FPURegister fs);
+  void cvt_w_d(FPURegister fd, FPURegister fs);
+
+  void cvt_l_s(FPURegister fd, FPURegister fs);
+  void cvt_l_d(FPURegister fd, FPURegister fs);
+
+  void cvt_s_w(FPURegister fd, FPURegister fs);
+  void cvt_s_l(FPURegister fd, FPURegister fs);
+  void cvt_s_d(FPURegister fd, FPURegister fs);
+
+  void cvt_d_w(FPURegister fd, FPURegister fs);
+  void cvt_d_l(FPURegister fd, FPURegister fs);
+  void cvt_d_s(FPURegister fd, FPURegister fs);
+
+  // Conditions and branches.
+  void c(FPUCondition cond, SecondaryField fmt,
+         FPURegister ft, FPURegister fs, uint16_t cc = 0);
+
+  void bc1f(int16_t offset, uint16_t cc = 0);
+  void bc1f(Label* L, uint16_t cc = 0) { bc1f(branch_offset(L, false)>>2, cc); }
+  void bc1t(int16_t offset, uint16_t cc = 0);
+  void bc1t(Label* L, uint16_t cc = 0) { bc1t(branch_offset(L, false)>>2, cc); }
+
+
+  // Check the code size generated from label to here.
+  int InstructionsGeneratedSince(Label* l) {
+    return (pc_offset() - l->pos()) / kInstrSize;
+  }
+
+  // Debugging.
+
+  // Mark address of the ExitJSFrame code.
+  void RecordJSReturn();
+
+  // Record a comment relocation entry that can be used by a disassembler.
+  // Use --debug_code to enable.
+  void RecordComment(const char* msg);
+
+  void RecordPosition(int pos);
+  void RecordStatementPosition(int pos);
+  void WriteRecordedPositions();
+
+  int32_t pc_offset() const { return pc_ - buffer_; }
+  int32_t current_position() const { return current_position_; }
+  int32_t current_statement_position() const { return current_position_; }
+
+  // Check if there is less than kGap bytes available in the buffer.
+  // If this is the case, we need to grow the buffer before emitting
+  // an instruction or relocation information.
+  inline bool overflow() const { return pc_ >= reloc_info_writer.pos() - kGap; }
+
+  // Get the number of bytes available in the buffer.
+  inline int available_space() const { return reloc_info_writer.pos() - pc_; }
+
+ protected:
+  int32_t buffer_space() const { return reloc_info_writer.pos() - pc_; }
+
+  // Read/patch instructions.
+  static Instr instr_at(byte* pc) { return *reinterpret_cast<Instr*>(pc); }
+  void instr_at_put(byte* pc, Instr instr) {
+    *reinterpret_cast<Instr*>(pc) = instr;
+  }
+  Instr instr_at(int pos) { return *reinterpret_cast<Instr*>(buffer_ + pos); }
+  void instr_at_put(int pos, Instr instr) {
+    *reinterpret_cast<Instr*>(buffer_ + pos) = instr;
+  }
+
+  // Check if an instruction is a branch of some kind.
+  bool is_branch(Instr instr);
+
+  // Decode branch instruction at pos and return branch target pos.
+  int target_at(int32_t pos);
+
+  // Patch branch instruction at pos to branch to given branch target pos.
+  void target_at_put(int32_t pos, int32_t target_pos);
+
+  // Say if we need to relocate with this mode.
+  bool MustUseAt(RelocInfo::Mode rmode);
+
+  // Record reloc info for current pc_.
+  void RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data = 0);
+
+ private:
+  // Code buffer:
+  // The buffer into which code and relocation info are generated.
+  byte* buffer_;
+  int buffer_size_;
+  // True if the assembler owns the buffer, false if buffer is external.
+  bool own_buffer_;
+
+  // Buffer size and constant pool distance are checked together at regular
+  // intervals of kBufferCheckInterval emitted bytes.
+  static const int kBufferCheckInterval = 1*KB/2;
+
+  // Code generation.
+  // The relocation writer's position is at least kGap bytes below the end of
+  // the generated instructions. This is so that multi-instruction sequences do
+  // not have to check for overflow. The same is true for writes of large
+  // relocation info entries.
+  static const int kGap = 32;
+  byte* pc_;  // The program counter - moves forward.
+
+  // Relocation information generation.
+  // Each relocation is encoded as a variable size value.
+  static const int kMaxRelocSize = RelocInfoWriter::kMaxSize;
+  RelocInfoWriter reloc_info_writer;
+
+  // The bound position, before this we cannot do instruction elimination.
+  int last_bound_pos_;
+
+  // Source position information.
+  int current_position_;
+  int current_statement_position_;
+  int written_position_;
+  int written_statement_position_;
+
+  // Code emission.
+  inline void CheckBuffer();
+  void GrowBuffer();
+  inline void emit(Instr x);
+
+  // Instruction generation.
+  // We have 3 different kind of encoding layout on MIPS.
+  // However due to many different types of objects encoded in the same fields
+  // we have quite a few aliases for each mode.
+  // Using the same structure to refer to Register and FPURegister would spare a
+  // few aliases, but mixing both does not look clean to me.
+  // Anyway we could surely implement this differently.
+
+  void GenInstrRegister(Opcode opcode,
+                        Register rs,
+                        Register rt,
+                        Register rd,
+                        uint16_t sa = 0,
+                        SecondaryField func = NULLSF);
+
+  void GenInstrRegister(Opcode opcode,
+                        SecondaryField fmt,
+                        FPURegister ft,
+                        FPURegister fs,
+                        FPURegister fd,
+                        SecondaryField func = NULLSF);
+
+  void GenInstrRegister(Opcode opcode,
+                        SecondaryField fmt,
+                        Register rt,
+                        FPURegister fs,
+                        FPURegister fd,
+                        SecondaryField func = NULLSF);
+
+
+  void GenInstrImmediate(Opcode opcode,
+                         Register rs,
+                         Register rt,
+                         int32_t  j);
+  void GenInstrImmediate(Opcode opcode,
+                         Register rs,
+                         SecondaryField SF,
+                         int32_t  j);
+  void GenInstrImmediate(Opcode opcode,
+                         Register r1,
+                         FPURegister r2,
+                         int32_t  j);
+
+
+  void GenInstrJump(Opcode opcode,
+                     uint32_t address);
+
+
+  // Labels.
+  void print(Label* L);
+  void bind_to(Label* L, int pos);
+  void link_to(Label* L, Label* appendix);
+  void next(Label* L);
+
+  friend class RegExpMacroAssemblerMIPS;
+  friend class RelocInfo;
+};
+
+} }  // namespace v8::internal
+
+#endif  // V8_ARM_ASSEMBLER_MIPS_H_
+