1 /*
   2  * Copyright (c) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
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  23  */
  24 
  25 #ifndef SHARE_VM_RUNTIME_JAVAFRAMEANCHOR_HPP
  26 #define SHARE_VM_RUNTIME_JAVAFRAMEANCHOR_HPP
  27 
  28 #include "runtime/orderAccess.inline.hpp"
  29 #include "utilities/globalDefinitions.hpp"
  30 #include "utilities/macros.hpp"
  31 
  32 //
  33 // An object for encapsulating the machine/os dependent part of a JavaThread frame state
  34 //
  35 class JavaThread;
  36 
  37 class JavaFrameAnchor {
  38 // Too many friends...
  39 friend class CallNativeDirectNode;
  40 friend class OptoRuntime;
  41 friend class Runtime1;
  42 friend class StubAssembler;
  43 friend class CallRuntimeDirectNode;
  44 friend class MacroAssembler;
  45 friend class LIR_Assembler;
  46 friend class GraphKit;
  47 friend class StubGenerator;
  48 friend class JavaThread;
  49 friend class frame;
  50 friend class VMStructs;
  51 friend class JVMCIVMStructs;
  52 friend class BytecodeInterpreter;
  53 friend class JavaCallWrapper;
  54 
  55  private:
  56   //
  57   // Whenever _last_Java_sp != NULL other anchor fields MUST be valid!
  58   // The stack may not be walkable [check with walkable() ] but the values must be valid.
  59   // The profiler apparently depends on this.
  60   //
  61   intptr_t* volatile _last_Java_sp;
  62 
  63   // Whenever we call from Java to native we can not be assured that the return
  64   // address that composes the last_Java_frame will be in an accessible location
  65   // so calls from Java to native store that pc (or one good enough to locate
  66   // the oopmap) in the frame anchor. Since the frames that call from Java to
  67   // native are never deoptimized we never need to patch the pc and so this
  68   // is acceptable.
  69   volatile  address _last_Java_pc;
  70 
  71   // tells whether the last Java frame is set
  72   // It is important that when last_Java_sp != NULL that the rest of the frame
  73   // anchor (including platform specific) all be valid.
  74 
  75   bool has_last_Java_frame() const                   { return _last_Java_sp != NULL; }
  76   // This is very dangerous unless sp == NULL
  77   // Invalidate the anchor so that has_last_frame is false
  78   // and no one should look at the other fields.
  79   void zap(void)                                     { _last_Java_sp = NULL; }
  80 
  81 #include CPU_HEADER(javaFrameAnchor)
  82 
  83 public:
  84   JavaFrameAnchor()                              { clear(); }
  85   JavaFrameAnchor(JavaFrameAnchor *src)          { copy(src); }
  86 
  87   void set_last_Java_pc(address pc)              { _last_Java_pc = pc; }
  88 
  89   // Assembly stub generation helpers
  90 
  91   static ByteSize last_Java_sp_offset()          { return byte_offset_of(JavaFrameAnchor, _last_Java_sp); }
  92   static ByteSize last_Java_pc_offset()          { return byte_offset_of(JavaFrameAnchor, _last_Java_pc); }
  93 
  94 };
  95 
  96 #endif // SHARE_VM_RUNTIME_JAVAFRAMEANCHOR_HPP