/*

 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.

 * Copyright (c) 2016 SAP SE. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

// Major contributions by JL, LS

#include "precompiled.hpp"

#include "asm/macroAssembler.inline.hpp"

#include "memory/resourceArea.hpp"

#include "nativeInst_s390.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/handles.hpp"

#include "runtime/sharedRuntime.hpp"

#include "runtime/stubRoutines.hpp"

#include "utilities/ostream.hpp"

#ifdef COMPILER1

#include "c1/c1_Runtime1.hpp"

#endif

#define LUCY_DBG

//-------------------------------------

//  N a t i v e I n s t r u c t i o n

//-------------------------------------

// Define this switch to prevent identity updates.

// In high-concurrency scenarios, it is beneficial to prevent

// identity updates. It has a positive effect on cache line steals.

// and invalidations.

// Test runs of JVM98, JVM2008, and JBB2005 show a very low frequency

// of identity updates. Detection is therefore disabled.

#undef SUPPRESS_IDENTITY_UPDATE

void NativeInstruction::verify() {

  // Make sure code pattern is actually an instruction address.

  // Do not allow:

  //  - NULL

  //  - any address in first page (0x0000 .. 0x0fff)

  //  - odd address (will cause a "specification exception")

  address addr = addr_at(0);

  if ((addr == 0) || (((unsigned long)addr & ~0x0fff) == 0) || ((intptr_t)addr & 1) != 0) {

    tty->print_cr(INTPTR_FORMAT ": bad instruction address", p2i(addr));

    fatal("not an instruction address");

  }

}

// Print location and value (hex representation) of current NativeInstruction

void NativeInstruction::print(const char* msg) const {

  int len = Assembler::instr_len(addr_at(0));

  if (msg == NULL) { // Output line without trailing blanks.

    switch (len) {

      case 2: tty->print_cr(INTPTR_FORMAT "(len=%d): %4.4x",             p2i(addr_at(0)), len, halfword_at(0));                                 break;

      case 4: tty->print_cr(INTPTR_FORMAT "(len=%d): %4.4x %4.4x",       p2i(addr_at(0)), len, halfword_at(0), halfword_at(2));                 break;

      case 6: tty->print_cr(INTPTR_FORMAT "(len=%d): %4.4x %4.4x %4.4x", p2i(addr_at(0)), len, halfword_at(0), halfword_at(2), halfword_at(4)); break;

      default: // Never reached. instr_len() always returns one of the above values. Keep the compiler happy.

        ShouldNotReachHere();

        break;

    }

  } else { // Output line with filler blanks to have msg aligned.

    switch (len) {

      case 2: tty->print_cr(INTPTR_FORMAT "(len=%d): %4.4x           %s",   p2i(addr_at(0)), len, halfword_at(0), msg);                                 break;

      case 4: tty->print_cr(INTPTR_FORMAT "(len=%d): %4.4x %4.4x      %s",  p2i(addr_at(0)), len, halfword_at(0), halfword_at(2), msg);                 break;

      case 6: tty->print_cr(INTPTR_FORMAT "(len=%d): %4.4x %4.4x %4.4x %s", p2i(addr_at(0)), len, halfword_at(0), halfword_at(2), halfword_at(4), msg); break;

      default: // Never reached. instr_len() always returns one of the above values. Keep the compiler happy.

        ShouldNotReachHere();

        break;

    }

  }

}

void NativeInstruction::print() const {

  print(NULL);

}

// Hex-Dump of storage around current NativeInstruction. Also try disassembly.

void NativeInstruction::dump(const unsigned int range, const char* msg) const {

  Assembler::dump_code_range(tty, addr_at(0), range, (msg == NULL) ? "":msg);

}

void NativeInstruction::dump(const unsigned int range) const {

  dump(range, NULL);

}

void NativeInstruction::dump() const {

  dump(32, NULL);

}

void NativeInstruction::set_halfword_at(int offset, short i) {

  address addr = addr_at(offset);

#ifndef SUPPRESS_IDENTITY_UPDATE

  *(short*)addr = i;

#else

  if (*(short*)addr != i) {

    *(short*)addr = i;

  }

#endif

  ICache::invalidate_word(addr);

}

void NativeInstruction::set_word_at(int offset, int i) {

  address addr = addr_at(offset);

#ifndef SUPPRESS_IDENTITY_UPDATE

  *(int*)addr = i;

#else

  if (*(int*)addr != i) {

    *(int*)addr = i;

  }

#endif

  ICache::invalidate_word(addr);

}

void NativeInstruction::set_jlong_at(int offset, jlong i) {

  address addr = addr_at(offset);

#ifndef SUPPRESS_IDENTITY_UPDATE

  *(jlong*)addr = i;

#else

  if (*(jlong*)addr != i) {

    *(jlong*)addr = i;

  }

#endif

  // Don't need to invalidate 2 words here, because

  // the flush instruction operates on doublewords.

  ICache::invalidate_word(addr);

}

#undef  SUPPRESS_IDENTITY_UPDATE

//------------------------------------------------------------

int NativeInstruction::illegal_instruction() {

  return 0;

}

bool NativeInstruction::is_illegal() {

  // An instruction with main opcode 0x00 (leftmost byte) is not a valid instruction

  // (and will never be) and causes a SIGILL where the pc points to the next instruction.

  // The caller of this method wants to know if such a situation exists at the current pc.

  //

  // The result of this method is unsharp with respect to the following facts:

  // - Stepping backwards in the instruction stream is not possible on z/Architecture.

  // - z/Architecture instructions are 2, 4, or 6 bytes in length.

  // - The instruction length is coded in the leftmost two bits of the main opcode.

  // - The result is exact if the caller knows by some other means that the

  //   instruction is of length 2.

  //

  // If this method returns false, then the 2-byte instruction at *-2 is not a 0x00 opcode.

  // If this method returns true, then the 2-byte instruction at *-2 is a 0x00 opcode.

  return halfword_at(-2) == illegal_instruction();

}

// We use an illtrap for marking a method as not_entrant or zombie.

bool NativeInstruction::is_sigill_zombie_not_entrant() {

  if (!is_illegal()) return false; // Just a quick path.

  // One-sided error of is_illegal tolerable here

  // (see implementation of is_illegal() for details).

  CodeBlob* cb = CodeCache::find_blob_unsafe(addr_at(0));

  if (cb == NULL || !cb->is_nmethod()) {

    return false;

  }

  nmethod *nm = (nmethod *)cb;

  // This method is not_entrant or zombie if the illtrap instruction

  // is located at the verified entry point.

  // BE AWARE: the current pc (this) points to the instruction after the

  // "illtrap" location.

  address sig_addr = ((address) this) - 2;

  return nm->verified_entry_point() == sig_addr;

}

bool NativeInstruction::is_jump() {

  unsigned long inst;

  Assembler::get_instruction((address)this, &inst);

  return MacroAssembler::is_branch_pcrelative_long(inst);

}

//---------------------------------------------------

//  N a t i v e I l l e g a l I n s t r u c t i o n

//---------------------------------------------------

void NativeIllegalInstruction::insert(address code_pos) {

  NativeIllegalInstruction* nii = (NativeIllegalInstruction*) nativeInstruction_at(code_pos);

  nii->set_halfword_at(0, illegal_instruction());

}

//-----------------------

//  N a t i v e C a l l

//-----------------------

void NativeCall::verify() {

  if (NativeCall::is_call_at(addr_at(0))) return;

  fatal("this is not a `NativeCall' site");

}

address NativeCall::destination() const {

  if (MacroAssembler::is_call_far_pcrelative(instruction_address())) {

    address here = addr_at(MacroAssembler::nop_size());

    return MacroAssembler::get_target_addr_pcrel(here);

  }

  return (address)((NativeMovConstReg *)this)->data();

}

// Similar to replace_mt_safe, but just changes the destination. The

// important thing is that free-running threads are able to execute this

// call instruction at all times. Thus, the displacement field must be

// 4-byte-aligned. We enforce this on z/Architecture by inserting a nop

// instruction in front of 'brasl' when needed.

//

// Used in the runtime linkage of calls; see class CompiledIC.

void NativeCall::set_destination_mt_safe(address dest) {

  if (MacroAssembler::is_call_far_pcrelative(instruction_address())) {

    address iaddr = addr_at(MacroAssembler::nop_size());

    // Ensure that patching is atomic hence mt safe.

    assert(((long)addr_at(MacroAssembler::call_far_pcrelative_size()) & (call_far_pcrelative_displacement_alignment-1)) == 0,

           "constant must be 4-byte aligned");

    set_word_at(MacroAssembler::call_far_pcrelative_size() - 4, Assembler::z_pcrel_off(dest, iaddr));

  } else {

    assert(MacroAssembler::is_load_const_from_toc(instruction_address()), "unsupported instruction");

    nativeMovConstReg_at(instruction_address())->set_data(((intptr_t)dest));

  }

}

//-----------------------------

//  N a t i v e F a r C a l l

//-----------------------------

void NativeFarCall::verify() {

  NativeInstruction::verify();

  if (NativeFarCall::is_far_call_at(addr_at(0))) return;

  fatal("not a NativeFarCall");

}

address NativeFarCall::destination() {

  assert(MacroAssembler::is_call_far_patchable_at((address)this), "unexpected call type");

  address ctable = NULL;

  return MacroAssembler::get_dest_of_call_far_patchable_at((address)this, ctable);

}

// Handles both patterns of patchable far calls.

void NativeFarCall::set_destination(address dest, int toc_offset) {

  address inst_addr = (address)this;

  // Set new destination (implementation of call may change here).

  assert(MacroAssembler::is_call_far_patchable_at(inst_addr), "unexpected call type");

  if (!MacroAssembler::is_call_far_patchable_pcrelative_at(inst_addr)) {

    address ctable = CodeCache::find_blob(inst_addr)->ctable_begin();

    // Need distance of TOC entry from current instruction.

    toc_offset = (ctable + toc_offset) - inst_addr;

    // Call is via constant table entry.

    MacroAssembler::set_dest_of_call_far_patchable_at(inst_addr, dest, toc_offset);

  } else {

    // Here, we have a pc-relative call (brasl).

    // Be aware: dest may have moved in this case, so really patch the displacement,

    // when necessary!

    // This while loop will also consume the nop which always preceeds a call_far_pcrelative.

    // We need to revert this after the loop. Pc-relative calls are always assumed to have a leading nop.

    unsigned int nop_sz    = MacroAssembler::nop_size();

    unsigned int nop_bytes = 0;

    while(MacroAssembler::is_z_nop(inst_addr+nop_bytes)) {

      nop_bytes += nop_sz;

    }

    if (nop_bytes > 0) {

      inst_addr += nop_bytes - nop_sz;

    }

    assert(MacroAssembler::is_call_far_pcrelative(inst_addr), "not a pc-relative call");

    address target = MacroAssembler::get_target_addr_pcrel(inst_addr + nop_sz);

    if (target != dest) {

      NativeCall *call = nativeCall_at(inst_addr);

      call->set_destination_mt_safe(dest);

    }

  }

}

//-------------------------------------

//  N a t i v e M o v C o n s t R e g

//-------------------------------------

// Do not use an assertion here. Let clients decide whether they only

// want this when assertions are enabled.

void NativeMovConstReg::verify() {

  address   loc = addr_at(0);

  // This while loop will also consume the nop which always preceeds a

  // call_far_pcrelative.  We need to revert this after the

  // loop. Pc-relative calls are always assumed to have a leading nop.

  unsigned int nop_sz    = MacroAssembler::nop_size();

  unsigned int nop_bytes = 0;

  while(MacroAssembler::is_z_nop(loc+nop_bytes)) {

    nop_bytes += nop_sz;

  }

  if (nop_bytes > 0) {

    if (MacroAssembler::is_call_far_pcrelative(loc+nop_bytes-nop_sz)) return;

    loc += nop_bytes;

  }

  if (!MacroAssembler::is_load_const_from_toc(loc)            &&    // Load const from TOC.

      !MacroAssembler::is_load_const(loc)                     &&    // Load const inline.

      !MacroAssembler::is_load_narrow_oop(loc)                &&    // Load narrow oop.

      !MacroAssembler::is_load_narrow_klass(loc)              &&    // Load narrow Klass ptr.

      !MacroAssembler::is_compare_immediate_narrow_oop(loc)   &&    // Compare immediate narrow.

      !MacroAssembler::is_compare_immediate_narrow_klass(loc) &&    // Compare immediate narrow.

      !MacroAssembler::is_pcrelative_instruction(loc)) {            // Just to make it run.

    tty->cr();

    tty->print_cr("NativeMovConstReg::verify(): verifying addr %p(0x%x), %d leading nops", loc, *(uint*)loc, nop_bytes/nop_sz);

    tty->cr();

    ((NativeMovConstReg*)loc)->dump(64, "NativeMovConstReg::verify()");

#ifdef LUCY_DBG

    VM_Version::z_SIGSEGV();

#endif

    fatal("this is not a `NativeMovConstReg' site");

  }

}

address NativeMovConstReg::next_instruction_address(int offset) const  {

  address inst_addr = addr_at(offset);

  // Load address (which is a constant) pc-relative.

  if (MacroAssembler::is_load_addr_pcrel(inst_addr))                  { return addr_at(offset+MacroAssembler::load_addr_pcrel_size()); }

  // Load constant from TOC.

  if (MacroAssembler::is_load_const_from_toc(inst_addr))              { return addr_at(offset+MacroAssembler::load_const_from_toc_size()); }

  // Load constant inline.

  if (MacroAssembler::is_load_const(inst_addr))                       { return addr_at(offset+MacroAssembler::load_const_size()); }

  // Load constant narrow inline.

  if (MacroAssembler::is_load_narrow_oop(inst_addr))                  { return addr_at(offset+MacroAssembler::load_narrow_oop_size()); }

  if (MacroAssembler::is_load_narrow_klass(inst_addr))                { return addr_at(offset+MacroAssembler::load_narrow_klass_size()); }

  // Compare constant narrow inline.

  if (MacroAssembler::is_compare_immediate_narrow_oop(inst_addr))     { return addr_at(offset+MacroAssembler::compare_immediate_narrow_oop_size()); }

  if (MacroAssembler::is_compare_immediate_narrow_klass(inst_addr))   { return addr_at(offset+MacroAssembler::compare_immediate_narrow_klass_size()); }

  if (MacroAssembler::is_call_far_patchable_pcrelative_at(inst_addr)) { return addr_at(offset+MacroAssembler::call_far_patchable_size()); }

  if (MacroAssembler::is_pcrelative_instruction(inst_addr))           { return addr_at(offset+Assembler::instr_len(inst_addr)); }

  ((NativeMovConstReg*)inst_addr)->dump(64, "NativeMovConstReg site is not recognized as such");

#ifdef LUCY_DBG

  VM_Version::z_SIGSEGV();

#else

  guarantee(false, "Not a NativeMovConstReg site");

#endif

  return NULL;

}

intptr_t NativeMovConstReg::data() const {

  address loc = addr_at(0);

  if (MacroAssembler::is_load_const(loc)) {

    return MacroAssembler::get_const(loc);

  } else if (MacroAssembler::is_load_narrow_oop(loc)              ||

             MacroAssembler::is_compare_immediate_narrow_oop(loc) ||

             MacroAssembler::is_load_narrow_klass(loc)            ||

             MacroAssembler::is_compare_immediate_narrow_klass(loc)) {

    ((NativeMovConstReg*)loc)->dump(32, "NativeMovConstReg::data(): cannot extract data from narrow ptr (oop or klass)");

#ifdef LUCY_DBG

    VM_Version::z_SIGSEGV();

#else

    ShouldNotReachHere();

#endif

    return *(intptr_t *)NULL;

  } else {

    // Otherwise, assume data resides in TOC. Is asserted in called method.

    return MacroAssembler::get_const_from_toc(loc);

  }

}

// Patch in a new constant.

//

// There are situations where we have multiple (hopefully two at most)

// relocations connected to one instruction. Loading an oop from CP

// using pcrelative addressing would one such example. Here we have an

// oop relocation, modifying the oop itself, and an internal word relocation,

// modifying the relative address.

//

// NativeMovConstReg::set_data is then called once for each relocation. To be

// able to distinguish between the relocations, we use a rather dirty hack:

//

// All calls that deal with an internal word relocation to fix their relative

// address are on a faked, odd instruction address. The instruction can be

// found on the next lower, even address.

//

// All other calls are "normal", i.e. on even addresses.

address NativeMovConstReg::set_data_plain(intptr_t src, CodeBlob *cb) {

  unsigned long x = (unsigned long)src;

  address loc = instruction_address();

  address next_address;

  if (MacroAssembler::is_load_addr_pcrel(loc)) {

    MacroAssembler::patch_target_addr_pcrel(loc, (address)src);

    ICache::invalidate_range(loc, MacroAssembler::load_addr_pcrel_size());

    next_address = next_instruction_address();

  } else if (MacroAssembler::is_load_const_from_toc(loc)) {  // Load constant from TOC.

    MacroAssembler::set_const_in_toc(loc, src, cb);

    next_address = next_instruction_address();

  } else if (MacroAssembler::is_load_const(loc)) {

    // Not mt safe, ok in methods like CodeBuffer::copy_code().

    MacroAssembler::patch_const(loc, x);

    ICache::invalidate_range(loc, MacroAssembler::load_const_size());

    next_address = next_instruction_address();

  }

  // cOops

  else if (MacroAssembler::is_load_narrow_oop(loc)) {

    MacroAssembler::patch_load_narrow_oop(loc, (oop) (void*) x);

    ICache::invalidate_range(loc, MacroAssembler::load_narrow_oop_size());

    next_address = next_instruction_address();

  }

  // compressed klass ptrs

  else if (MacroAssembler::is_load_narrow_klass(loc)) {

    MacroAssembler::patch_load_narrow_klass(loc, (Klass*)x);

    ICache::invalidate_range(loc, MacroAssembler::load_narrow_klass_size());

    next_address = next_instruction_address();

  }

  // cOops

  else if (MacroAssembler::is_compare_immediate_narrow_oop(loc)) {

    MacroAssembler::patch_compare_immediate_narrow_oop(loc, (oop) (void*) x);

    ICache::invalidate_range(loc, MacroAssembler::compare_immediate_narrow_oop_size());

    next_address = next_instruction_address();

  }

  // compressed klass ptrs

  else if (MacroAssembler::is_compare_immediate_narrow_klass(loc)) {

    MacroAssembler::patch_compare_immediate_narrow_klass(loc, (Klass*)x);

    ICache::invalidate_range(loc, MacroAssembler::compare_immediate_narrow_klass_size());

    next_address = next_instruction_address();

  }

  else if (MacroAssembler::is_call_far_patchable_pcrelative_at(loc)) {

    assert(ShortenBranches, "Wait a minute! A pc-relative call w/o ShortenBranches?");

    // This NativeMovConstReg site does not need to be patched. It was

    // patched when it was converted to a call_pcrelative site

    // before. The value of the src argument is not related to the

    // branch target.

    next_address = next_instruction_address();

  }

  else {

    tty->print_cr("WARNING: detected an unrecognized code pattern at loc = %p -> 0x%8.8x %8.8x",

                  loc, *((unsigned int*)loc), *((unsigned int*)(loc+4)));

    next_address = next_instruction_address(); // Failure should be handled in next_instruction_address().

#ifdef LUCY_DBG

    VM_Version::z_SIGSEGV();

#endif

  }

  return next_address;

}

// Divided up in set_data_plain() which patches the instruction in the

// code stream and set_data() which additionally patches the oop pool

// if necessary.

void NativeMovConstReg::set_data(intptr_t src) {

  // Also store the value into an oop_Relocation cell, if any.

  CodeBlob *cb = CodeCache::find_blob(instruction_address());

  address next_address = set_data_plain(src, cb);

  relocInfo::update_oop_pool(instruction_address(), next_address, (address)src, cb);

}

void NativeMovConstReg::set_narrow_oop(intptr_t data) {

  const address start = addr_at(0);

  int           range = 0;

  if (MacroAssembler::is_load_narrow_oop(start)) {

    range = MacroAssembler::patch_load_narrow_oop(start, cast_to_oop <intptr_t> (data));

  } else if (MacroAssembler::is_compare_immediate_narrow_oop(start)) {

    range = MacroAssembler::patch_compare_immediate_narrow_oop(start, cast_to_oop <intptr_t>(data));

  } else {

    fatal("this is not a `NativeMovConstReg::narrow_oop' site");

  }

  ICache::invalidate_range(start, range);

}

// Compressed klass ptrs. patch narrow klass constant.

void NativeMovConstReg::set_narrow_klass(intptr_t data) {

  const address start = addr_at(0);

  int           range = 0;

  if (MacroAssembler::is_load_narrow_klass(start)) {

    range = MacroAssembler::patch_load_narrow_klass(start, (Klass*)data);

  } else if (MacroAssembler::is_compare_immediate_narrow_klass(start)) {

    range = MacroAssembler::patch_compare_immediate_narrow_klass(start, (Klass*)data);

  } else {

    fatal("this is not a `NativeMovConstReg::narrow_klass' site");

  }

  ICache::invalidate_range(start, range);

}

void NativeMovConstReg::set_pcrel_addr(intptr_t newTarget, CompiledMethod *passed_nm /* = NULL */, bool copy_back_to_oop_pool) {

  address next_address;

  address loc = addr_at(0);

  if (MacroAssembler::is_load_addr_pcrel(loc)) {

    address oldTarget = MacroAssembler::get_target_addr_pcrel(loc);

    MacroAssembler::patch_target_addr_pcrel(loc, (address)newTarget);

    ICache::invalidate_range(loc, MacroAssembler::load_addr_pcrel_size());

    next_address = loc + MacroAssembler::load_addr_pcrel_size();

  } else if (MacroAssembler::is_load_const_from_toc_pcrelative(loc) ) {  // Load constant from TOC.

    address oldTarget = MacroAssembler::get_target_addr_pcrel(loc);

    MacroAssembler::patch_target_addr_pcrel(loc, (address)newTarget);

    ICache::invalidate_range(loc, MacroAssembler::load_const_from_toc_size());

    next_address = loc + MacroAssembler::load_const_from_toc_size();