S390: Initial impl of S390 asm, masm, code-stubs,...

src/s390/assembler-s390-inl.h

Index: src/s390/assembler-s390-inl.h
diff --git a/src/ppc/assembler-ppc-inl.h b/src/s390/assembler-s390-inl.h
similarity index 54%
copy from src/ppc/assembler-ppc-inl.h
copy to src/s390/assembler-s390-inl.h
index 42e220809f5771b0f8a8ca9c68de83e46db386c0..14413d60a156c1873fe8d2504ee292c35d00ede8 100644
--- a/src/ppc/assembler-ppc-inl.h
+++ b/src/s390/assembler-s390-inl.h
@@ -34,28 +34,35 @@
 // 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_
+#ifndef V8_S390_ASSEMBLER_S390_INL_H_
+#define V8_S390_ASSEMBLER_S390_INL_H_
 
-#include "src/ppc/assembler-ppc.h"
+#include "src/s390/assembler-s390.h"
 
 #include "src/assembler.h"
 #include "src/debug/debug.h"
 
-
 namespace v8 {
 namespace internal {
 
-
 bool CpuFeatures::SupportsCrankshaft() { return true; }
 
-
 void RelocInfo::apply(intptr_t delta) {
-  // absolute code pointer inside code object moves with the code object.
+  // Absolute code pointer inside code object moves with the code object.
   if (IsInternalReference(rmode_)) {
     // Jump table entry
     Address target = Memory::Address_at(pc_);
     Memory::Address_at(pc_) = target + delta;
+  } else if (IsCodeTarget(rmode_)) {
+    SixByteInstr instr =
+        Instruction::InstructionBits(reinterpret_cast<const byte*>(pc_));
+    int32_t dis = static_cast<int32_t>(instr & 0xFFFFFFFF) * 2  // halfwords
+                  - static_cast<int32_t>(delta);
+    instr >>= 32;  // Clear the 4-byte displacement field.
+    instr <<= 32;
+    instr |= static_cast<uint32_t>(dis / 2);
+    Instruction::SetInstructionBits<SixByteInstr>(reinterpret_cast<byte*>(pc_),
+                                                  instr);
   } else {
     // mov sequence
     DCHECK(IsInternalReferenceEncoded(rmode_));
@@ -65,7 +72,6 @@ void RelocInfo::apply(intptr_t delta) {
   }
 }
 
-
 Address RelocInfo::target_internal_reference() {
   if (IsInternalReference(rmode_)) {
     // Jump table entry
@@ -77,31 +83,20 @@ Address RelocInfo::target_internal_reference() {
   }
 }
 
-
 Address RelocInfo::target_internal_reference_address() {
   DCHECK(IsInternalReference(rmode_) || IsInternalReferenceEncoded(rmode_));
   return reinterpret_cast<Address>(pc_);
 }
 
-
 Address RelocInfo::target_address() {
   DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_));
   return Assembler::target_address_at(pc_, host_);
 }
 
-
 Address RelocInfo::target_address_address() {
   DCHECK(IsCodeTarget(rmode_) || IsRuntimeEntry(rmode_) ||
          rmode_ == EMBEDDED_OBJECT || rmode_ == EXTERNAL_REFERENCE);
 
-  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 reinterpret_cast<Address>(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.
@@ -114,24 +109,13 @@ Address RelocInfo::target_address_address() {
   return reinterpret_cast<Address>(pc_);
 }
 
-
 Address RelocInfo::constant_pool_entry_address() {
-  if (FLAG_enable_embedded_constant_pool) {
-    Address constant_pool = host_->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();
   return NULL;
 }
 
-
 int RelocInfo::target_address_size() { return Assembler::kSpecialTargetSize; }
 
-
 void RelocInfo::set_target_address(Address target,
                                    WriteBarrierMode write_barrier_mode,
                                    ICacheFlushMode icache_flush_mode) {
@@ -146,53 +130,42 @@ void RelocInfo::set_target_address(Address target,
   }
 }
 
-
 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;
+  // Returns the address of the call target from the return address that will
+  // be returned to after a call.
+  // Sequence is:
+  //    BRASL r14, RI
+  return pc - kCallTargetAddressOffset;
 }
 
-
 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;
+  // Sequence is:
+  //    BRASL r14, RI
+  return pc + kCallTargetAddressOffset;
 }
 
+Handle<Object> Assembler::code_target_object_handle_at(Address pc) {
+  SixByteInstr instr =
+      Instruction::InstructionBits(reinterpret_cast<const byte*>(pc));
+  int index = instr & 0xFFFFFFFF;
+  return code_targets_[index];
+}
 
 Object* RelocInfo::target_object() {
   DCHECK(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
   return reinterpret_cast<Object*>(Assembler::target_address_at(pc_, host_));
 }
 
-
 Handle<Object> RelocInfo::target_object_handle(Assembler* origin) {
   DCHECK(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
-  return Handle<Object>(
-      reinterpret_cast<Object**>(Assembler::target_address_at(pc_, host_)));
+  if (rmode_ == EMBEDDED_OBJECT) {
+    return Handle<Object>(
+        reinterpret_cast<Object**>(Assembler::target_address_at(pc_, host_)));
+  } else {
+    return origin->code_target_object_handle_at(pc_);
+  }
 }
 
-
 void RelocInfo::set_target_object(Object* target,
                                   WriteBarrierMode write_barrier_mode,
                                   ICacheFlushMode icache_flush_mode) {
@@ -207,19 +180,16 @@ void RelocInfo::set_target_object(Object* target,
   }
 }
 
-
 Address RelocInfo::target_external_reference() {
   DCHECK(rmode_ == EXTERNAL_REFERENCE);
   return Assembler::target_address_at(pc_, host_);
 }
 
-
 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) {
@@ -228,20 +198,17 @@ void RelocInfo::set_target_runtime_entry(Address target,
     set_target_address(target, write_barrier_mode, icache_flush_mode);
 }
 
-
 Handle<Cell> RelocInfo::target_cell_handle() {
   DCHECK(rmode_ == RelocInfo::CELL);
   Address address = Memory::Address_at(pc_);
   return Handle<Cell>(reinterpret_cast<Cell**>(address));
 }
 
-
 Cell* RelocInfo::target_cell() {
   DCHECK(rmode_ == RelocInfo::CELL);
   return Cell::FromValueAddress(Memory::Address_at(pc_));
 }
 
-
 void RelocInfo::set_target_cell(Cell* cell, WriteBarrierMode write_barrier_mode,
                                 ICacheFlushMode icache_flush_mode) {
   DCHECK(rmode_ == RelocInfo::CELL);
@@ -253,37 +220,40 @@ void RelocInfo::set_target_cell(Cell* cell, WriteBarrierMode write_barrier_mode,
   }
 }
 
-
-static const int kNoCodeAgeInstructions =
-    FLAG_enable_embedded_constant_pool ? 7 : 6;
-static const int kCodeAgingInstructions =
-    Assembler::kMovInstructionsNoConstantPool + 3;
-static const int kNoCodeAgeSequenceInstructions =
-    ((kNoCodeAgeInstructions >= kCodeAgingInstructions)
-         ? kNoCodeAgeInstructions
-         : kCodeAgingInstructions);
-static const int kNoCodeAgeSequenceNops =
-    (kNoCodeAgeSequenceInstructions - kNoCodeAgeInstructions);
-static const int kCodeAgingSequenceNops =
-    (kNoCodeAgeSequenceInstructions - kCodeAgingInstructions);
-static const int kCodeAgingTargetDelta = 1 * Assembler::kInstrSize;
-static const int kNoCodeAgeSequenceLength =
-    (kNoCodeAgeSequenceInstructions * Assembler::kInstrSize);
-
+#if V8_TARGET_ARCH_S390X
+// NOP(2byte) + PUSH + MOV + BASR =
+// NOP + LAY + STG + IIHF + IILF + BASR
+static const int kCodeAgingSequenceLength = 28;
+static const int kCodeAgingTargetDelta = 14;  // Jump past NOP + PUSH to IIHF
+                                              // LAY + 4 * STG + LA
+static const int kNoCodeAgeSequenceLength = 34;
+#else
+#if (V8_HOST_ARCH_S390)
+// NOP + NILH + LAY + ST + IILF + BASR
+static const int kCodeAgingSequenceLength = 24;
+static const int kCodeAgingTargetDelta = 16;  // Jump past NOP to IILF
+// NILH + LAY + 4 * ST + LA
+static const int kNoCodeAgeSequenceLength = 30;
+#else
+// NOP + LAY + ST + IILF + BASR
+static const int kCodeAgingSequenceLength = 20;
+static const int kCodeAgingTargetDelta = 12;  // Jump past NOP to IILF
+// LAY + 4 * ST + LA
+static const int kNoCodeAgeSequenceLength = 26;
+#endif
+#endif
 
 Handle<Object> RelocInfo::code_age_stub_handle(Assembler* origin) {
-  UNREACHABLE();  // This should never be reached on PPC.
+  UNREACHABLE();  // This should never be reached on S390.
   return Handle<Object>();
 }
 
-
 Code* RelocInfo::code_age_stub() {
   DCHECK(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
   return Code::GetCodeFromTargetAddress(
       Assembler::target_address_at(pc_ + kCodeAgingTargetDelta, host_));
 }
 
-
 void RelocInfo::set_code_age_stub(Code* stub,
                                   ICacheFlushMode icache_flush_mode) {
   DCHECK(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
@@ -292,13 +262,11 @@ void RelocInfo::set_code_age_stub(Code* stub,
                                    icache_flush_mode);
 }
 
-
 Address RelocInfo::debug_call_address() {
   DCHECK(IsDebugBreakSlot(rmode()) && IsPatchedDebugBreakSlotSequence());
   return Assembler::target_address_at(pc_, host_);
 }
 
-
 void RelocInfo::set_debug_call_address(Address target) {
   DCHECK(IsDebugBreakSlot(rmode()) && IsPatchedDebugBreakSlotSequence());
   Assembler::set_target_address_at(isolate_, pc_, host_, target);
@@ -309,7 +277,6 @@ void RelocInfo::set_debug_call_address(Address target) {
   }
 }
 
-
 void RelocInfo::WipeOut() {
   DCHECK(IsEmbeddedObject(rmode_) || IsCodeTarget(rmode_) ||
          IsRuntimeEntry(rmode_) || IsExternalReference(rmode_) ||
@@ -327,7 +294,6 @@ void RelocInfo::WipeOut() {
   }
 }
 
-
 void RelocInfo::Visit(Isolate* isolate, ObjectVisitor* visitor) {
   RelocInfo::Mode mode = rmode();
   if (mode == RelocInfo::EMBEDDED_OBJECT) {
@@ -338,8 +304,7 @@ void RelocInfo::Visit(Isolate* isolate, ObjectVisitor* visitor) {
     visitor->VisitCell(this);
   } else if (mode == RelocInfo::EXTERNAL_REFERENCE) {
     visitor->VisitExternalReference(this);
-  } else if (mode == RelocInfo::INTERNAL_REFERENCE ||
-             mode == RelocInfo::INTERNAL_REFERENCE_ENCODED) {
+  } else if (mode == RelocInfo::INTERNAL_REFERENCE) {
     visitor->VisitInternalReference(this);
   } else if (RelocInfo::IsCodeAgeSequence(mode)) {
     visitor->VisitCodeAgeSequence(this);
@@ -351,7 +316,6 @@ void RelocInfo::Visit(Isolate* isolate, ObjectVisitor* visitor) {
   }
 }
 
-
 template <typename StaticVisitor>
 void RelocInfo::Visit(Heap* heap) {
   RelocInfo::Mode mode = rmode();
@@ -363,8 +327,7 @@ void RelocInfo::Visit(Heap* heap) {
     StaticVisitor::VisitCell(heap, this);
   } else if (mode == RelocInfo::EXTERNAL_REFERENCE) {
     StaticVisitor::VisitExternalReference(this);
-  } else if (mode == RelocInfo::INTERNAL_REFERENCE ||
-             mode == RelocInfo::INTERNAL_REFERENCE_ENCODED) {
+  } else if (mode == RelocInfo::INTERNAL_REFERENCE) {
     StaticVisitor::VisitInternalReference(this);
   } else if (RelocInfo::IsCodeAgeSequence(mode)) {
     StaticVisitor::VisitCodeAgeSequence(heap, this);
@@ -376,6 +339,7 @@ void RelocInfo::Visit(Heap* heap) {
   }
 }
 
+// Operand constructors
 Operand::Operand(intptr_t immediate, RelocInfo::Mode rmode) {
   rm_ = no_reg;
   imm_ = immediate;
@@ -396,7 +360,7 @@ Operand::Operand(Smi* value) {
 
 Operand::Operand(Register rm) {
   rm_ = rm;
-  rmode_ = kRelocInfo_NONEPTR;  // PPC -why doesn't ARM do this?
+  rmode_ = kRelocInfo_NONEPTR;  // S390 -why doesn't ARM do this?
 }
 
 void Assembler::CheckBuffer() {
@@ -405,202 +369,117 @@ void Assembler::CheckBuffer() {
   }
 }
 
-void Assembler::TrackBranch() {
-  DCHECK(!trampoline_emitted_);
-  int count = tracked_branch_count_++;
-  if (count == 0) {
-    // We leave space (kMaxBlockTrampolineSectionSize)
-    // for BlockTrampolinePoolScope buffer.
-    next_trampoline_check_ =
-        pc_offset() + kMaxCondBranchReach - kMaxBlockTrampolineSectionSize;
+int32_t Assembler::emit_code_target(Handle<Code> target, RelocInfo::Mode rmode,
+                                    TypeFeedbackId ast_id) {
+  DCHECK(RelocInfo::IsCodeTarget(rmode));
+  if (rmode == RelocInfo::CODE_TARGET && !ast_id.IsNone()) {
+    SetRecordedAstId(ast_id);
+    RecordRelocInfo(RelocInfo::CODE_TARGET_WITH_ID);
   } else {
-    next_trampoline_check_ -= kTrampolineSlotsSize;
+    RecordRelocInfo(rmode);
   }
-}
 
-void Assembler::UntrackBranch() {
-  DCHECK(!trampoline_emitted_);
-  DCHECK(tracked_branch_count_ > 0);
-  int count = --tracked_branch_count_;
-  if (count == 0) {
-    // Reset
-    next_trampoline_check_ = kMaxInt;
+  int current = code_targets_.length();
+  if (current > 0 && code_targets_.last().is_identical_to(target)) {
+    // Optimization if we keep jumping to the same code target.
+    current--;
   } else {
-    next_trampoline_check_ += kTrampolineSlotsSize;
-  }
-}
-
-void Assembler::CheckTrampolinePoolQuick() {
-  if (pc_offset() >= next_trampoline_check_) {
-    CheckTrampolinePool();
+    code_targets_.Add(target);
   }
+  return current;
 }
 
-void Assembler::emit(Instr x) {
+// Helper to emit the binary encoding of a 2 byte instruction
+void Assembler::emit2bytes(uint16_t x) {
   CheckBuffer();
-  *reinterpret_cast<Instr*>(pc_) = x;
-  pc_ += kInstrSize;
-  CheckTrampolinePoolQuick();
+#if V8_TARGET_LITTLE_ENDIAN
+  // We need to emit instructions in big endian format as disassembler /
+  // simulator require the first byte of the instruction in order to decode
+  // the instruction length.  Swap the bytes.
+  x = ((x & 0x00FF) << 8) | ((x & 0xFF00) >> 8);
+#endif
+  *reinterpret_cast<uint16_t*>(pc_) = x;
+  pc_ += 2;
 }
 
-bool Operand::is_reg() const { return rm_.is_valid(); }
-
-
-// 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_at(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 reinterpret_cast<Address>((hi << 32) | lo);
-#else
-    // Assemble the 32 bit value.
-    return reinterpret_cast<Address>(((instr1 & kImm16Mask) << 16) |
-                                     (instr2 & kImm16Mask));
+// Helper to emit the binary encoding of a 4 byte instruction
+void Assembler::emit4bytes(uint32_t x) {
+  CheckBuffer();
+#if V8_TARGET_LITTLE_ENDIAN
+  // We need to emit instructions in big endian format as disassembler /
+  // simulator require the first byte of the instruction in order to decode
+  // the instruction length.  Swap the bytes.
+  x = ((x & 0x000000FF) << 24) | ((x & 0x0000FF00) << 8) |
+      ((x & 0x00FF0000) >> 8) | ((x & 0xFF000000) >> 24);
 #endif
-  }
-
-  UNREACHABLE();
-  return NULL;
+  *reinterpret_cast<uint32_t*>(pc_) = x;
+  pc_ += 4;
 }
 
-
-#if V8_TARGET_ARCH_PPC64
-const int kLoadIntptrOpcode = LD;
+// Helper to emit the binary encoding of a 6 byte instruction
+void Assembler::emit6bytes(uint64_t x) {
+  CheckBuffer();
+#if V8_TARGET_LITTLE_ENDIAN
+  // We need to emit instructions in big endian format as disassembler /
+  // simulator require the first byte of the instruction in order to decode
+  // the instruction length.  Swap the bytes.
+  x = (static_cast<uint64_t>(x & 0xFF) << 40) |
+      (static_cast<uint64_t>((x >> 8) & 0xFF) << 32) |
+      (static_cast<uint64_t>((x >> 16) & 0xFF) << 24) |
+      (static_cast<uint64_t>((x >> 24) & 0xFF) << 16) |
+      (static_cast<uint64_t>((x >> 32) & 0xFF) << 8) |
+      (static_cast<uint64_t>((x >> 40) & 0xFF));
+  x |= (*reinterpret_cast<uint64_t*>(pc_) >> 48) << 48;
 #else
-const int 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);
-  int opcode = instr & kOpcodeMask;
-  if (!GetRA(instr).is(kConstantPoolRegister)) return false;
-  bool overflowed = (opcode == ADDIS);
-#ifdef DEBUG
-  if (overflowed) {
-    opcode = instr_at(pc + kInstrSize) & kOpcodeMask;
-  }
-  DCHECK(opcode == kLoadIntptrOpcode || opcode == LFD);
+  // We need to pad two bytes of zeros in order to get the 6-bytes
+  // stored from low address.
+  x = x << 16;
+  x |= *reinterpret_cast<uint64_t*>(pc_) & 0xFFFF;
 #endif
-  if (access) {
-    *access = (overflowed ? ConstantPoolEntry::OVERFLOWED
-                          : ConstantPoolEntry::REGULAR);
-  }
-  return true;
+  // It is safe to store 8-bytes, as CheckBuffer() guarantees we have kGap
+  // space left over.
+  *reinterpret_cast<uint64_t*>(pc_) = x;
+  pc_ += 6;
 }
 
+bool Operand::is_reg() const { return rm_.is_valid(); }
 
-bool Assembler::IsConstantPoolLoadEnd(Address pc,
-                                      ConstantPoolEntry::Access* access) {
-  Instr instr = instr_at(pc);
-  int opcode = instr & kOpcodeMask;
-  bool overflowed = false;
-  if (!(opcode == kLoadIntptrOpcode || opcode == LFD)) return false;
-  if (!GetRA(instr).is(kConstantPoolRegister)) {
-    instr = instr_at(pc - kInstrSize);
-    opcode = instr & kOpcodeMask;
-    if ((opcode != ADDIS) || !GetRA(instr).is(kConstantPoolRegister)) {
-      return false;
-    }
-    overflowed = true;
-  }
-  if (access) {
-    *access = (overflowed ? ConstantPoolEntry::OVERFLOWED
-                          : ConstantPoolEntry::REGULAR);
+// Fetch the 32bit value from the FIXED_SEQUENCE IIHF / IILF
+Address Assembler::target_address_at(Address pc, Address constant_pool) {
+  // S390 Instruction!
+  // We want to check for instructions generated by Asm::mov()
+  Opcode op1 = Instruction::S390OpcodeValue(reinterpret_cast<const byte*>(pc));
+  SixByteInstr instr_1 =
+      Instruction::InstructionBits(reinterpret_cast<const byte*>(pc));
+
+  if (BRASL == op1 || BRCL == op1) {
+    int32_t dis = static_cast<int32_t>(instr_1 & 0xFFFFFFFF) * 2;
+    return reinterpret_cast<Address>(reinterpret_cast<uint64_t>(pc) + dis);
   }
-  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));
+#if V8_TARGET_ARCH_S390X
+  int instr1_length =
+      Instruction::InstructionLength(reinterpret_cast<const byte*>(pc));
+  Opcode op2 = Instruction::S390OpcodeValue(
+      reinterpret_cast<const byte*>(pc + instr1_length));
+  SixByteInstr instr_2 = Instruction::InstructionBits(
+      reinterpret_cast<const byte*>(pc + instr1_length));
+  // IIHF for hi_32, IILF for lo_32
+  if (IIHF == op1 && IILF == op2) {
+    return reinterpret_cast<Address>(((instr_1 & 0xFFFFFFFF) << 32) |
+                                     ((instr_2 & 0xFFFFFFFF)));
   }
-  return offset;
-}
-
-
-void Assembler::PatchConstantPoolAccessInstruction(
-    int pc_offset, int offset, ConstantPoolEntry::Access access,
-    ConstantPoolEntry::Type type) {
-  Address pc = 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);
+#else
+  // IILF loads 32-bits
+  if (IILF == op1 || CFI == op1) {
+    return reinterpret_cast<Address>((instr_1 & 0xFFFFFFFF));
   }
-}
-
+#endif
 
-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;
+  UNIMPLEMENTED();
+  return (Address)0;
 }
 
-
 // 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.
@@ -610,7 +489,6 @@ void Assembler::deserialization_set_special_target_at(
   set_target_address_at(isolate, instruction_payload, code, target);
 }
 
-
 void Assembler::deserialization_set_target_internal_reference_at(
     Isolate* isolate, Address pc, Address target, RelocInfo::Mode mode) {
   if (RelocInfo::IsInternalReferenceEncoded(mode)) {
@@ -621,75 +499,77 @@ void Assembler::deserialization_set_target_internal_reference_at(
   }
 }
 
-
-// This code assumes the FIXED_SEQUENCE of lis/ori
+// This code assumes the FIXED_SEQUENCE of IIHF/IILF
 void Assembler::set_target_address_at(Isolate* isolate, 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_at(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 = reinterpret_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;
+  // Check for instructions generated by Asm::mov()
+  Opcode op1 = Instruction::S390OpcodeValue(reinterpret_cast<const byte*>(pc));
+  SixByteInstr instr_1 =
+      Instruction::InstructionBits(reinterpret_cast<const byte*>(pc));
+  bool patched = false;
+
+  if (BRASL == op1 || BRCL == op1) {
+    instr_1 >>= 32;  // Zero out the lower 32-bits
+    instr_1 <<= 32;
+    int32_t halfwords = (target - pc) / 2;  // number of halfwords
+    instr_1 |= static_cast<uint32_t>(halfwords);
+    Instruction::SetInstructionBits<SixByteInstr>(reinterpret_cast<byte*>(pc),
+                                                  instr_1);
     if (icache_flush_mode != SKIP_ICACHE_FLUSH) {
-      Assembler::FlushICache(isolate, p, 5 * kInstrSize);
+      Assembler::FlushICache(isolate, pc, 6);
+    }
+    patched = true;
+  } else {
+#if V8_TARGET_ARCH_S390X
+    int instr1_length =
+        Instruction::InstructionLength(reinterpret_cast<const byte*>(pc));
+    Opcode op2 = Instruction::S390OpcodeValue(
+        reinterpret_cast<const byte*>(pc + instr1_length));
+    SixByteInstr instr_2 = Instruction::InstructionBits(
+        reinterpret_cast<const byte*>(pc + instr1_length));
+    // IIHF for hi_32, IILF for lo_32
+    if (IIHF == op1 && IILF == op2) {
+      // IIHF
+      instr_1 >>= 32;  // Zero out the lower 32-bits
+      instr_1 <<= 32;
+      instr_1 |= reinterpret_cast<uint64_t>(target) >> 32;
+
+      Instruction::SetInstructionBits<SixByteInstr>(reinterpret_cast<byte*>(pc),
+                                                    instr_1);
+
+      // IILF
+      instr_2 >>= 32;
+      instr_2 <<= 32;
+      instr_2 |= reinterpret_cast<uint64_t>(target) & 0xFFFFFFFF;
+
+      Instruction::SetInstructionBits<SixByteInstr>(
+          reinterpret_cast<byte*>(pc + instr1_length), instr_2);
+      if (icache_flush_mode != SKIP_ICACHE_FLUSH) {
+        Assembler::FlushICache(isolate, pc, 12);
+      }
+      patched = true;
     }
 #else
-    uint32_t* p = reinterpret_cast<uint32_t*>(pc);
-    uint32_t itarget = reinterpret_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(isolate, p, 2 * kInstrSize);
+    // IILF loads 32-bits
+    if (IILF == op1 || CFI == op1) {
+      instr_1 >>= 32;  // Zero out the lower 32-bits
+      instr_1 <<= 32;
+      instr_1 |= reinterpret_cast<uint32_t>(target);
+
+      Instruction::SetInstructionBits<SixByteInstr>(reinterpret_cast<byte*>(pc),
+                                                    instr_1);
+      if (icache_flush_mode != SKIP_ICACHE_FLUSH) {
+        Assembler::FlushICache(isolate, pc, 6);
+      }
+      patched = true;
     }
 #endif
-    return;
   }
-  UNREACHABLE();
+  if (!patched) UNREACHABLE();
 }
+
 }  // namespace internal
 }  // namespace v8
 
-#endif  // V8_PPC_ASSEMBLER_PPC_INL_H_
+#endif  // V8_S390_ASSEMBLER_S390_INL_H_