src/hotspot/cpu/x86/gc/shared/barrierSetNMethod_x86.cpp

rev 57113 : 8230765: Implement nmethod barrier for x86_32 platforms
Reviewed-by: rkennke, eosterlund

*** 1,7 ****
  /*
!  * Copyright (c) 2018, Oracle and/or its affiliates. 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.
--- 1,7 ----
  /*
!  * Copyright (c) 2018, 2019, Oracle and/or its affiliates. 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.
*** 33,58 ****
--- 33,68 ----
  #include "utilities/align.hpp"
  #include "utilities/debug.hpp"
  
  class NativeNMethodCmpBarrier: public NativeInstruction {
  public:
+ #ifdef _LP64
    enum Intel_specific_constants {
      instruction_code        = 0x81,
      instruction_size        = 8,
      imm_offset              = 4,
      instruction_rex_prefix  = Assembler::REX | Assembler::REX_B,
      instruction_modrm       = 0x7f  // [r15 + offset]
    };
+ #else
+   enum Intel_specific_constants {
+     instruction_code        = 0x81,
+     instruction_size        = 7,
+     imm_offset              = 2,
+     instruction_modrm       = 0x3f  // [rdi]
+   };
+ #endif
  
    address instruction_address() const { return addr_at(0); }
    address immediate_address() const { return addr_at(imm_offset); }
  
    jint get_immedate() const { return int_at(imm_offset); }
    void set_immediate(jint imm) { set_int_at(imm_offset, imm); }
    void verify() const;
  };
  
+ #ifdef _LP64
  void NativeNMethodCmpBarrier::verify() const {
    if (((uintptr_t) instruction_address()) & 0x7) {
      fatal("Not properly aligned");
    }
  
*** 75,84 ****
--- 85,115 ----
      tty->print_cr("Addr: " INTPTR_FORMAT " mod/rm: 0x%x", p2i(instruction_address()),
          modrm);
      fatal("not a cmp barrier");
    }
  }
+ #else
+ void NativeNMethodCmpBarrier::verify() const {
+   if (((uintptr_t) instruction_address()) & 0x3) {
+     fatal("Not properly aligned");
+   }
+ 
+   int inst = ubyte_at(0);
+   if (inst != instruction_code) {
+     tty->print_cr("Addr: " INTPTR_FORMAT " Code: 0x%x", p2i(instruction_address()),
+         inst);
+     fatal("not a cmp barrier");
+   }
+ 
+   int modrm = ubyte_at(1);
+   if (modrm != instruction_modrm) {
+     tty->print_cr("Addr: " INTPTR_FORMAT " mod/rm: 0x%x", p2i(instruction_address()),
+         modrm);
+     fatal("not a cmp barrier");
+   }
+ }
+ #endif // _LP64
  
  void BarrierSetNMethod::deoptimize(nmethod* nm, address* return_address_ptr) {
    /*
     * [ callers frame          ]
     * [ callers return address ] <- callers rsp
*** 125,135 ****
  // If any code changes between the end of the verified entry where the entry
  // barrier resides, and the completion of the frame, then
  // NativeNMethodCmpBarrier::verify() will immediately complain when it does
  // not find the expected native instruction at this offset, which needs updating.
  // Note that this offset is invariant of PreserveFramePointer.
! static const int entry_barrier_offset = -19;
  
  static NativeNMethodCmpBarrier* native_nmethod_barrier(nmethod* nm) {
    address barrier_address = nm->code_begin() + nm->frame_complete_offset() + entry_barrier_offset;
    NativeNMethodCmpBarrier* barrier = reinterpret_cast<NativeNMethodCmpBarrier*>(barrier_address);
    debug_only(barrier->verify());
--- 156,166 ----
  // If any code changes between the end of the verified entry where the entry
  // barrier resides, and the completion of the frame, then
  // NativeNMethodCmpBarrier::verify() will immediately complain when it does
  // not find the expected native instruction at this offset, which needs updating.
  // Note that this offset is invariant of PreserveFramePointer.
! static const int entry_barrier_offset = LP64_ONLY(-19) NOT_LP64(-18);
  
  static NativeNMethodCmpBarrier* native_nmethod_barrier(nmethod* nm) {
    address barrier_address = nm->code_begin() + nm->frame_complete_offset() + entry_barrier_offset;
    NativeNMethodCmpBarrier* barrier = reinterpret_cast<NativeNMethodCmpBarrier*>(barrier_address);
    debug_only(barrier->verify());