assembler-ppc-inl.h

// 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
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// 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 2014 the V8 project authors. All rights reserved.

#ifndef V8_PPC_ASSEMBLER_PPC_INL_H_
#define V8_PPC_ASSEMBLER_PPC_INL_H_

#include "src/ppc/assembler-ppc.h"

#include "src/assembler.h"
#include "src/debug/debug.h"
#include "src/objects-inl.h"

namespace v8 {
namespace internal {

bool CpuFeatures::SupportsOptimizer() { return true; }

bool CpuFeatures::SupportsWasmSimd128() { return false; }

void RelocInfo::apply(intptr_t delta) {
  // absolute code pointer inside code object moves with the code object.
  if (IsInternalReference(rmode_)) {
    // Jump table entry
    Address target = Memory<Address>(pc_);
    Memory<Address>(pc_) = target + delta;
  } else {
    // mov sequence
    DCHECK(IsInternalReferenceEncoded(rmode_));
    Address target = Assembler::target_address_at(pc_, constant_pool_);
    Assembler::set_target_address_at(pc_, constant_pool_, target + delta,
                                     SKIP_ICACHE_FLUSH);
  }
}


Address RelocInfo::target_internal_reference() {
  if (IsInternalReference(rmode_)) {
    // Jump table entry
    return Memory<Address>(pc_);
  } else {
    // mov sequence
    DCHECK(IsInternalReferenceEncoded(rmode_));
    return Assembler::target_address_at(pc_, constant_pool_);
  }
}


Address RelocInfo::target_internal_reference_address() {
  DCHECK(IsInternalReference(rmode_) || IsInternalReferenceEncoded(rmode_));
  return pc_;
}


Address RelocInfo::target_address() {
  DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_) || IsWasmCall(rmode_));
  return Assembler::target_address_at(pc_, constant_pool_);
}

Address RelocInfo::target_address_address() {
  DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_) || IsWasmCall(rmode_) ||
         IsEmbeddedObject(rmode_) || IsExternalReference(rmode_) ||
         IsOffHeapTarget(rmode_));

  if (FLAG_enable_embedded_constant_pool &&
      Assembler::IsConstantPoolLoadStart(pc_)) {
    // We return the PC for embedded constant pool since this function is used
    // by the serializer and expects the address to reside within the code
    // object.
    return pc_;
  }

  // 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 instruction like LIS/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.
  return pc_;
}


Address RelocInfo::constant_pool_entry_address() {
  if (FLAG_enable_embedded_constant_pool) {
    DCHECK(constant_pool_);
    ConstantPoolEntry::Access access;
    if (Assembler::IsConstantPoolLoadStart(pc_, &access))
      return Assembler::target_constant_pool_address_at(
          pc_, constant_pool_, access, ConstantPoolEntry::INTPTR);
  }
  UNREACHABLE();
}


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

Address Assembler::target_address_from_return_address(Address pc) {
// Returns the address of the call target from the return address that will
// be returned to after a call.
// Call sequence is :
//  mov   ip, @ call address
//  mtlr  ip
//  blrl
//                      @ return address
  int len;
  ConstantPoolEntry::Access access;
  if (FLAG_enable_embedded_constant_pool &&
      IsConstantPoolLoadEnd(pc - 3 * kInstrSize, &access)) {
    len = (access == ConstantPoolEntry::OVERFLOWED) ? 2 : 1;
  } else {
    len = kMovInstructionsNoConstantPool;
  }
  return pc - (len + 2) * kInstrSize;
}


Address Assembler::return_address_from_call_start(Address pc) {
  int len;
  ConstantPoolEntry::Access access;
  if (FLAG_enable_embedded_constant_pool &&
      IsConstantPoolLoadStart(pc, &access)) {
    len = (access == ConstantPoolEntry::OVERFLOWED) ? 2 : 1;
  } else {
    len = kMovInstructionsNoConstantPool;
  }
  return pc + (len + 2) * kInstrSize;
}

HeapObject* RelocInfo::target_object() {
  DCHECK(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
  return HeapObject::cast(reinterpret_cast<Object*>(
      Assembler::target_address_at(pc_, constant_pool_)));
}

Handle<HeapObject> RelocInfo::target_object_handle(Assembler* origin) {
  DCHECK(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
  return Handle<HeapObject>(reinterpret_cast<Address*>(
      Assembler::target_address_at(pc_, constant_pool_)));
}

void RelocInfo::set_target_object(Heap* heap, HeapObject* target,
                                  WriteBarrierMode write_barrier_mode,
                                  ICacheFlushMode icache_flush_mode) {
  DCHECK(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
  Assembler::set_target_address_at(pc_, constant_pool_,
                                   reinterpret_cast<Address>(target),
                                   icache_flush_mode);
  if (write_barrier_mode == UPDATE_WRITE_BARRIER && host() != nullptr) {
    WriteBarrierForCode(host(), this, target);
  }
}


Address RelocInfo::target_external_reference() {
  DCHECK(rmode_ == EXTERNAL_REFERENCE);
  return Assembler::target_address_at(pc_, constant_pool_);
}

void RelocInfo::set_target_external_reference(
    Address target, ICacheFlushMode icache_flush_mode) {
  DCHECK(rmode_ == RelocInfo::EXTERNAL_REFERENCE);
  Assembler::set_target_address_at(pc_, constant_pool_, target,
                                   icache_flush_mode);
}

Address RelocInfo::target_runtime_entry(Assembler* origin) {
  DCHECK(IsRuntimeEntry(rmode_));
  return target_address();
}

void RelocInfo::set_target_runtime_entry(Address target,
                                         WriteBarrierMode write_barrier_mode,
                                         ICacheFlushMode icache_flush_mode) {
  DCHECK(IsRuntimeEntry(rmode_));
  if (target_address() != target)
    set_target_address(target, write_barrier_mode, icache_flush_mode);
}

Address RelocInfo::target_off_heap_target() {
  DCHECK(IsOffHeapTarget(rmode_));
  return Assembler::target_address_at(pc_, constant_pool_);
}

void RelocInfo::WipeOut() {
  DCHECK(IsEmbeddedObject(rmode_) || IsCodeTarget(rmode_) ||
         IsRuntimeEntry(rmode_) || IsExternalReference(rmode_) ||
         IsInternalReference(rmode_) || IsInternalReferenceEncoded(rmode_) ||
         IsOffHeapTarget(rmode_));
  if (IsInternalReference(rmode_)) {
    // Jump table entry
    Memory<Address>(pc_) = kNullAddress;
  } else if (IsInternalReferenceEncoded(rmode_) || IsOffHeapTarget(rmode_)) {
    // mov sequence
    // Currently used only by deserializer, no need to flush.
    Assembler::set_target_address_at(pc_, constant_pool_, kNullAddress,
                                     SKIP_ICACHE_FLUSH);
  } else {
    Assembler::set_target_address_at(pc_, constant_pool_, kNullAddress);
  }
}

template <typename ObjectVisitor>
void RelocInfo::Visit(ObjectVisitor* visitor) {
  RelocInfo::Mode mode = rmode();
  if (mode == RelocInfo::EMBEDDED_OBJECT) {
    visitor->VisitEmbeddedPointer(host(), this);
  } else if (RelocInfo::IsCodeTargetMode(mode)) {
    visitor->VisitCodeTarget(host(), this);
  } else if (mode == RelocInfo::EXTERNAL_REFERENCE) {
    visitor->VisitExternalReference(host(), this);
  } else if (mode == RelocInfo::INTERNAL_REFERENCE ||
             mode == RelocInfo::INTERNAL_REFERENCE_ENCODED) {
    visitor->VisitInternalReference(host(), this);
  } else if (IsRuntimeEntry(mode)) {
    visitor->VisitRuntimeEntry(host(), this);
  } else if (RelocInfo::IsOffHeapTarget(mode)) {
    visitor->VisitOffHeapTarget(host(), this);
  }
}

Operand::Operand(Register rm) : rm_(rm), rmode_(RelocInfo::NONE) {}

void Assembler::UntrackBranch() {
  DCHECK(!trampoline_emitted_);
  DCHECK_GT(tracked_branch_count_, 0);
  int count = --tracked_branch_count_;
  if (count == 0) {
    // Reset
    next_trampoline_check_ = kMaxInt;
  } else {
    next_trampoline_check_ += kTrampolineSlotsSize;
  }
}

// Fetch the 32bit value from the FIXED_SEQUENCE lis/ori
Address Assembler::target_address_at(Address pc, Address constant_pool) {
  if (FLAG_enable_embedded_constant_pool && constant_pool) {
    ConstantPoolEntry::Access access;
    if (IsConstantPoolLoadStart(pc, &access))
      return Memory<Address>(target_constant_pool_address_at(
          pc, constant_pool, access, ConstantPoolEntry::INTPTR));
  }

  Instr instr1 = instr_at(pc);
  Instr instr2 = instr_at(pc + kInstrSize);
  // Interpret 2 instructions generated by lis/ori
  if (IsLis(instr1) && IsOri(instr2)) {
#if V8_TARGET_ARCH_PPC64
    Instr instr4 = instr_at(pc + (3 * kInstrSize));
    Instr instr5 = instr_at(pc + (4 * kInstrSize));
    // Assemble the 64 bit value.
    uint64_t hi = (static_cast<uint32_t>((instr1 & kImm16Mask) << 16) |
                   static_cast<uint32_t>(instr2 & kImm16Mask));
    uint64_t lo = (static_cast<uint32_t>((instr4 & kImm16Mask) << 16) |
                   static_cast<uint32_t>(instr5 & kImm16Mask));
    return static_cast<Address>((hi << 32) | lo);
#else
    // Assemble the 32 bit value.
    return static_cast<Address>(((instr1 & kImm16Mask) << 16) |
                                (instr2 & kImm16Mask));
#endif
  }

  UNREACHABLE();
}


#if V8_TARGET_ARCH_PPC64
const uint32_t kLoadIntptrOpcode = LD;
#else
const uint32_t kLoadIntptrOpcode = LWZ;
#endif

// Constant pool load sequence detection:
// 1) REGULAR access:
//    load <dst>, kConstantPoolRegister + <offset>
//
// 2) OVERFLOWED access:
//    addis <scratch>, kConstantPoolRegister, <offset_high>
//    load <dst>, <scratch> + <offset_low>
bool Assembler::IsConstantPoolLoadStart(Address pc,
                                        ConstantPoolEntry::Access* access) {
  Instr instr = instr_at(pc);
  uint32_t opcode = instr & kOpcodeMask;
  if (GetRA(instr) != kConstantPoolRegister) return false;
  bool overflowed = (opcode == ADDIS);
#ifdef DEBUG
  if (overflowed) {
    opcode = instr_at(pc + kInstrSize) & kOpcodeMask;
  }
  DCHECK(opcode == kLoadIntptrOpcode || opcode == LFD);
#endif
  if (access) {
    *access = (overflowed ? ConstantPoolEntry::OVERFLOWED
                          : ConstantPoolEntry::REGULAR);
  }
  return true;
}


bool Assembler::IsConstantPoolLoadEnd(Address pc,
                                      ConstantPoolEntry::Access* access) {
  Instr instr = instr_at(pc);
  uint32_t opcode = instr & kOpcodeMask;
  bool overflowed = false;
  if (!(opcode == kLoadIntptrOpcode || opcode == LFD)) return false;
  if (GetRA(instr) != kConstantPoolRegister) {
    instr = instr_at(pc - kInstrSize);
    opcode = instr & kOpcodeMask;
    if ((opcode != ADDIS) || GetRA(instr) != kConstantPoolRegister) {
      return false;
    }
    overflowed = true;
  }
  if (access) {
    *access = (overflowed ? ConstantPoolEntry::OVERFLOWED
                          : ConstantPoolEntry::REGULAR);
  }
  return true;
}


int Assembler::GetConstantPoolOffset(Address pc,
                                     ConstantPoolEntry::Access access,
                                     ConstantPoolEntry::Type type) {
  bool overflowed = (access == ConstantPoolEntry::OVERFLOWED);
#ifdef DEBUG
  ConstantPoolEntry::Access access_check =
      static_cast<ConstantPoolEntry::Access>(-1);
  DCHECK(IsConstantPoolLoadStart(pc, &access_check));
  DCHECK(access_check == access);
#endif
  int offset;
  if (overflowed) {
    offset = (instr_at(pc) & kImm16Mask) << 16;
    offset += SIGN_EXT_IMM16(instr_at(pc + kInstrSize) & kImm16Mask);
    DCHECK(!is_int16(offset));
  } else {
    offset = SIGN_EXT_IMM16((instr_at(pc) & kImm16Mask));
  }
  return offset;
}


void Assembler::PatchConstantPoolAccessInstruction(
    int pc_offset, int offset, ConstantPoolEntry::Access access,
    ConstantPoolEntry::Type type) {
  Address pc = reinterpret_cast<Address>(buffer_) + pc_offset;
  bool overflowed = (access == ConstantPoolEntry::OVERFLOWED);
  CHECK(overflowed != is_int16(offset));
#ifdef DEBUG
  ConstantPoolEntry::Access access_check =
      static_cast<ConstantPoolEntry::Access>(-1);
  DCHECK(IsConstantPoolLoadStart(pc, &access_check));
  DCHECK(access_check == access);
#endif
  if (overflowed) {
    int hi_word = static_cast<int>(offset >> 16);
    int lo_word = static_cast<int>(offset & 0xffff);
    if (lo_word & 0x8000) hi_word++;

    Instr instr1 = instr_at(pc);
    Instr instr2 = instr_at(pc + kInstrSize);
    instr1 &= ~kImm16Mask;
    instr1 |= (hi_word & kImm16Mask);
    instr2 &= ~kImm16Mask;
    instr2 |= (lo_word & kImm16Mask);
    instr_at_put(pc, instr1);
    instr_at_put(pc + kInstrSize, instr2);
  } else {
    Instr instr = instr_at(pc);
    instr &= ~kImm16Mask;
    instr |= (offset & kImm16Mask);
    instr_at_put(pc, instr);
  }
}


Address Assembler::target_constant_pool_address_at(
    Address pc, Address constant_pool, ConstantPoolEntry::Access access,
    ConstantPoolEntry::Type type) {
  Address addr = constant_pool;
  DCHECK(addr);
  addr += GetConstantPoolOffset(pc, access, type);
  return addr;
}


// This sets the branch destination (which gets loaded at the call address).
// This is for calls and branches within generated code.  The serializer
// has already deserialized the mov instructions etc.
// There is a FIXED_SEQUENCE assumption here
void Assembler::deserialization_set_special_target_at(
    Address instruction_payload, Code code, Address target) {
  set_target_address_at(instruction_payload,
                        code ? code->constant_pool() : kNullAddress, target);
}

int Assembler::deserialization_special_target_size(
    Address instruction_payload) {
  return kSpecialTargetSize;
}

void Assembler::deserialization_set_target_internal_reference_at(
    Address pc, Address target, RelocInfo::Mode mode) {
  if (RelocInfo::IsInternalReferenceEncoded(mode)) {
    set_target_address_at(pc, kNullAddress, target, SKIP_ICACHE_FLUSH);
  } else {
    Memory<Address>(pc) = target;
  }
}


// This code assumes the FIXED_SEQUENCE of lis/ori
void Assembler::set_target_address_at(Address pc, Address constant_pool,
                                      Address target,
                                      ICacheFlushMode icache_flush_mode) {
  if (FLAG_enable_embedded_constant_pool && constant_pool) {
    ConstantPoolEntry::Access access;
    if (IsConstantPoolLoadStart(pc, &access)) {
      Memory<Address>(target_constant_pool_address_at(
          pc, constant_pool, access, ConstantPoolEntry::INTPTR)) = target;
      return;
    }
  }

  Instr instr1 = instr_at(pc);
  Instr instr2 = instr_at(pc + kInstrSize);
  // Interpret 2 instructions generated by lis/ori
  if (IsLis(instr1) && IsOri(instr2)) {
#if V8_TARGET_ARCH_PPC64
    Instr instr4 = instr_at(pc + (3 * kInstrSize));
    Instr instr5 = instr_at(pc + (4 * kInstrSize));
    // Needs to be fixed up when mov changes to handle 64-bit values.
    uint32_t* p = reinterpret_cast<uint32_t*>(pc);
    uintptr_t itarget = static_cast<uintptr_t>(target);

    instr5 &= ~kImm16Mask;
    instr5 |= itarget & kImm16Mask;
    itarget = itarget >> 16;

    instr4 &= ~kImm16Mask;
    instr4 |= itarget & kImm16Mask;
    itarget = itarget >> 16;

    instr2 &= ~kImm16Mask;
    instr2 |= itarget & kImm16Mask;
    itarget = itarget >> 16;

    instr1 &= ~kImm16Mask;
    instr1 |= itarget & kImm16Mask;
    itarget = itarget >> 16;

    *p = instr1;
    *(p + 1) = instr2;
    *(p + 3) = instr4;
    *(p + 4) = instr5;
    if (icache_flush_mode != SKIP_ICACHE_FLUSH) {
      Assembler::FlushICache(p, 5 * kInstrSize);
    }
#else
    uint32_t* p = reinterpret_cast<uint32_t*>(pc);
    uint32_t itarget = static_cast<uint32_t>(target);
    int lo_word = itarget & kImm16Mask;
    int hi_word = itarget >> 16;
    instr1 &= ~kImm16Mask;
    instr1 |= hi_word;
    instr2 &= ~kImm16Mask;
    instr2 |= lo_word;

    *p = instr1;
    *(p + 1) = instr2;
    if (icache_flush_mode != SKIP_ICACHE_FLUSH) {
      Assembler::FlushICache(p, 2 * kInstrSize);
    }
#endif
    return;
  }
  UNREACHABLE();
}
}  // namespace internal
}  // namespace v8

#endif  // V8_PPC_ASSEMBLER_PPC_INL_H_