src/mips/assembler-mips-inl.h

// Copyright (c) 1994-2006 Sun Microsystems Inc.
// All Rights Reserved.
//
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// 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
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// - 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,
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// 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
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// 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_INL_H_
#define V8_MIPS_ASSEMBLER_MIPS_INL_H_

#include "mips/assembler-mips.h"
#include "cpu.h"
#include "debug.h"


namespace v8 {
namespace internal {

// -----------------------------------------------------------------------------
// Operand and MemOperand

Operand::Operand(int32_t immediate, RelocInfo::Mode rmode)  {
  rm_ = no_reg;
  imm32_ = immediate;
  rmode_ = rmode;
}


Operand::Operand(const ExternalReference& f)  {
  rm_ = no_reg;
  imm32_ = reinterpret_cast<int32_t>(f.address());
  rmode_ = RelocInfo::EXTERNAL_REFERENCE;
}


Operand::Operand(Smi* value) {
  rm_ = no_reg;
  imm32_ =  reinterpret_cast<intptr_t>(value);
  rmode_ = RelocInfo::NONE;
}


Operand::Operand(Register rm) {
  rm_ = rm;
}


bool Operand::is_reg() const {
  return rm_.is_valid();
}


// -----------------------------------------------------------------------------
// RelocInfo

void RelocInfo::apply(intptr_t delta) {
  // On MIPS we do not use pc relative addressing, so we don't need to patch the
  // code here.
}


Address RelocInfo::target_address() {
  ASSERT(IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY);
  return Assembler::target_address_at(pc_);
}


Address RelocInfo::target_address_address() {
  ASSERT(IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY
                              || rmode_ == EMBEDDED_OBJECT
                              || rmode_ == EXTERNAL_REFERENCE);
  // Read the address of the word containing the target_address in an
  // instruction stream.
  // The only architecture-independent user of this function is the serializer.
  // The serializer uses it to find out how many raw bytes of instruction to
  // output before the next target.
  // For an instructions like LUI/ORI where the target bits are mixed into the
  // instruction bits, the size of the target will be zero, indicating that the
  // serializer should not step forward in memory after a target is resolved
  // and written.  In this case the target_address_address function should
  // return the end of the instructions to be patched, allowing the
  // deserializer to deserialize the instructions as raw bytes and put them in
  // place, ready to be patched with the target. In our case, that is the
  // address of the instruction that follows LUI/ORI instruction pair.
  return reinterpret_cast<Address>(
    pc_ + Assembler::kInstructionsFor32BitConstant * Assembler::kInstrSize);
}


int RelocInfo::target_address_size() {
  return Assembler::kExternalTargetSize;
}


void RelocInfo::set_target_address(Address target) {
  ASSERT(IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY);
  Assembler::set_target_address_at(pc_, target);
}


Object* RelocInfo::target_object() {
  ASSERT(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
  return reinterpret_cast<Object*>(Assembler::target_address_at(pc_));
}


Handle<Object> RelocInfo::target_object_handle(Assembler *origin) {
  ASSERT(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
  return Handle<Object>(reinterpret_cast<Object**>(
      Assembler::target_address_at(pc_)));
}


Object** RelocInfo::target_object_address() {
  // Provide a "natural pointer" to the embedded object,
  // which can be de-referenced during heap iteration.
  ASSERT(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
  // TODO(mips): Commenting out, to simplify arch-independent changes.
  // GC won't work like this, but this commit is for asm/disasm/sim.
  // reconstructed_obj_ptr_ =
  //   reinterpret_cast<Object*>(Assembler::target_address_at(pc_));
  // return &reconstructed_obj_ptr_;
  return NULL;
}


void RelocInfo::set_target_object(Object* target) {
  ASSERT(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
  Assembler::set_target_address_at(pc_, reinterpret_cast<Address>(target));
}


Address* RelocInfo::target_reference_address() {
  ASSERT(rmode_ == EXTERNAL_REFERENCE);
  // TODO(mips): Commenting out, to simplify arch-independent changes.
  // GC won't work like this, but this commit is for asm/disasm/sim.
  // reconstructed_adr_ptr_ = Assembler::target_address_at(pc_);
  // return &reconstructed_adr_ptr_;
  return NULL;
}


Handle<JSGlobalPropertyCell> RelocInfo::target_cell_handle() {
  ASSERT(rmode_ == RelocInfo::GLOBAL_PROPERTY_CELL);
  Address address = Memory::Address_at(pc_);
  return Handle<JSGlobalPropertyCell>(
      reinterpret_cast<JSGlobalPropertyCell**>(address));
}


JSGlobalPropertyCell* RelocInfo::target_cell() {
  ASSERT(rmode_ == RelocInfo::GLOBAL_PROPERTY_CELL);
  Address address = Memory::Address_at(pc_);
  Object* object = HeapObject::FromAddress(
      address - JSGlobalPropertyCell::kValueOffset);
  return reinterpret_cast<JSGlobalPropertyCell*>(object);
}


void RelocInfo::set_target_cell(JSGlobalPropertyCell* cell) {
  ASSERT(rmode_ == RelocInfo::GLOBAL_PROPERTY_CELL);
  Address address = cell->address() + JSGlobalPropertyCell::kValueOffset;
  Memory::Address_at(pc_) = address;
}


Address RelocInfo::call_address() {
  ASSERT((IsJSReturn(rmode()) && IsPatchedReturnSequence()) ||
         (IsDebugBreakSlot(rmode()) && IsPatchedDebugBreakSlotSequence()));
  // The pc_ offset of 0 assumes mips patched return sequence per
  // debug-mips.cc BreakLocationIterator::SetDebugBreakAtReturn(), or
  // debug break slot per BreakLocationIterator::SetDebugBreakAtSlot().
  return Assembler::target_address_at(pc_);
}


void RelocInfo::set_call_address(Address target) {
  ASSERT((IsJSReturn(rmode()) && IsPatchedReturnSequence()) ||
         (IsDebugBreakSlot(rmode()) && IsPatchedDebugBreakSlotSequence()));
  // The pc_ offset of 0 assumes mips patched return sequence per
  // debug-mips.cc BreakLocationIterator::SetDebugBreakAtReturn(), or
  // debug break slot per BreakLocationIterator::SetDebugBreakAtSlot().
  Assembler::set_target_address_at(pc_, target);
}


Object* RelocInfo::call_object() {
  return *call_object_address();
}


Object** RelocInfo::call_object_address() {
  ASSERT((IsJSReturn(rmode()) && IsPatchedReturnSequence()) ||
         (IsDebugBreakSlot(rmode()) && IsPatchedDebugBreakSlotSequence()));
  return reinterpret_cast<Object**>(pc_ + 2 * Assembler::kInstrSize);
}


void RelocInfo::set_call_object(Object* target) {
  *call_object_address() = target;
}


bool RelocInfo::IsPatchedReturnSequence() {
  Instr instr0 = Assembler::instr_at(pc_);
  Instr instr1 = Assembler::instr_at(pc_ + 1 * Assembler::kInstrSize);
  Instr instr2 = Assembler::instr_at(pc_ + 2 * Assembler::kInstrSize);
  bool patched_return = ((instr0 & kOpcodeMask) == LUI &&
                         (instr1 & kOpcodeMask) == ORI &&
                         (instr2 & kOpcodeMask) == SPECIAL &&
                         (instr2 & kFunctionFieldMask) == JALR);
  return patched_return;
}


bool RelocInfo::IsPatchedDebugBreakSlotSequence() {
  Instr current_instr = Assembler::instr_at(pc_);
  return !Assembler::IsNop(current_instr, Assembler::DEBUG_BREAK_NOP);
}


void RelocInfo::Visit(ObjectVisitor* visitor) {
  RelocInfo::Mode mode = rmode();
  if (mode == RelocInfo::EMBEDDED_OBJECT) {
    // RelocInfo is needed when pointer must be updated/serialized, such as
    // UpdatingVisitor in mark-compact.cc or Serializer in serialize.cc.
    // It is ignored by visitors that do not need it.
    // Commenting out, to simplify arch-independednt changes.
    // GC won't work like this, but this commit is for asm/disasm/sim.
    // visitor->VisitPointer(target_object_address(), this);
  } else if (RelocInfo::IsCodeTarget(mode)) {
    visitor->VisitCodeTarget(this);
  } else if (mode == RelocInfo::EXTERNAL_REFERENCE) {
    // RelocInfo is needed when external-references must be serialized by
    // Serializer Visitor in serialize.cc. It is ignored by visitors that
    // do not need it.
    // Commenting out, to simplify arch-independednt changes.
    // Serializer won't work like this, but this commit is for asm/disasm/sim.
    // visitor->VisitExternalReference(target_reference_address(), this);
#ifdef ENABLE_DEBUGGER_SUPPORT
  // TODO(isolates): Get a cached isolate below.
  } else if (((RelocInfo::IsJSReturn(mode) &&
               IsPatchedReturnSequence()) ||
             (RelocInfo::IsDebugBreakSlot(mode) &&
               IsPatchedDebugBreakSlotSequence())) &&
             Isolate::Current()->debug()->has_break_points()) {
    visitor->VisitDebugTarget(this);
#endif
  } else if (mode == RelocInfo::RUNTIME_ENTRY) {
    visitor->VisitRuntimeEntry(this);
  }
}


template<typename StaticVisitor>
void RelocInfo::Visit(Heap* heap) {
  RelocInfo::Mode mode = rmode();
  if (mode == RelocInfo::EMBEDDED_OBJECT) {
    StaticVisitor::VisitPointer(heap, target_object_address());
  } else if (RelocInfo::IsCodeTarget(mode)) {
    StaticVisitor::VisitCodeTarget(this);
  } else if (mode == RelocInfo::EXTERNAL_REFERENCE) {
    StaticVisitor::VisitExternalReference(target_reference_address());
#ifdef ENABLE_DEBUGGER_SUPPORT
  } else if (heap->isolate()->debug()->has_break_points() &&
             ((RelocInfo::IsJSReturn(mode) &&
              IsPatchedReturnSequence()) ||
             (RelocInfo::IsDebugBreakSlot(mode) &&
              IsPatchedDebugBreakSlotSequence()))) {
    StaticVisitor::VisitDebugTarget(this);
#endif
  } else if (mode == RelocInfo::RUNTIME_ENTRY) {
    StaticVisitor::VisitRuntimeEntry(this);
  }
}


// -----------------------------------------------------------------------------
// Assembler


void Assembler::CheckBuffer() {
  if (buffer_space() <= kGap) {
    GrowBuffer();
  }
}


void Assembler::CheckTrampolinePoolQuick() {
  if (pc_offset() >= next_buffer_check_) {
    CheckTrampolinePool();
  }
}


void Assembler::emit(Instr x) {
  CheckBuffer();
  *reinterpret_cast<Instr*>(pc_) = x;
  pc_ += kInstrSize;
  CheckTrampolinePoolQuick();
}


} }  // namespace v8::internal

#endif  // V8_MIPS_ASSEMBLER_MIPS_INL_H_