view src/share/vm/c1/c1_CodeStubs.hpp @ 2346:e1162778c1c8

7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer. Reviewed-by: kvn, iveresov, never, tonyp, dholmes
author johnc
date Thu, 07 Apr 2011 09:53:20 -0700
parents e4fee0bdaa85
children 09aad8452938
line wrap: on
line source
/*
 * Copyright (c) 1999, 2011, 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.
 *
 * 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.
 *
 */

#ifndef SHARE_VM_C1_C1_CODESTUBS_HPP
#define SHARE_VM_C1_C1_CODESTUBS_HPP

#include "c1/c1_FrameMap.hpp"
#include "c1/c1_IR.hpp"
#include "c1/c1_Instruction.hpp"
#include "c1/c1_LIR.hpp"
#include "c1/c1_Runtime1.hpp"
#include "utilities/array.hpp"

class CodeEmitInfo;
class LIR_Assembler;
class LIR_OpVisitState;

// CodeStubs are little 'out-of-line' pieces of code that
// usually handle slow cases of operations. All code stubs
// are collected and code is emitted at the end of the
// nmethod.

class CodeStub: public CompilationResourceObj {
 protected:
  Label _entry;                                  // label at the stub entry point
  Label _continuation;                           // label where stub continues, if any

 public:
  CodeStub() {}

  // code generation
  void assert_no_unbound_labels()                { assert(!_entry.is_unbound() && !_continuation.is_unbound(), "unbound label"); }
  virtual void emit_code(LIR_Assembler* e) = 0;
  virtual CodeEmitInfo* info() const             { return NULL; }
  virtual bool is_exception_throw_stub() const   { return false; }
  virtual bool is_range_check_stub() const       { return false; }
  virtual bool is_divbyzero_stub() const         { return false; }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const = 0;
#endif

  // label access
  Label* entry()                                 { return &_entry; }
  Label* continuation()                          { return &_continuation; }
  // for LIR
  virtual void visit(LIR_OpVisitState* visit) {
#ifndef PRODUCT
    if (LIRTracePeephole && Verbose) {
      tty->print("no visitor for ");
      print_name(tty);
      tty->cr();
    }
#endif
  }
};


define_array(CodeStubArray, CodeStub*)
define_stack(_CodeStubList, CodeStubArray)

class CodeStubList: public _CodeStubList {
 public:
  CodeStubList(): _CodeStubList() {}

  void append(CodeStub* stub) {
    if (!contains(stub)) {
      _CodeStubList::append(stub);
    }
  }
};

class CounterOverflowStub: public CodeStub {
 private:
  CodeEmitInfo* _info;
  int           _bci;
  LIR_Opr       _method;

public:
  CounterOverflowStub(CodeEmitInfo* info, int bci, LIR_Opr method) :  _info(info), _bci(bci), _method(method) {
  }

  virtual void emit_code(LIR_Assembler* e);

  virtual void visit(LIR_OpVisitState* visitor) {
    visitor->do_slow_case(_info);
    visitor->do_input(_method);
  }

#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("CounterOverflowStub"); }
#endif // PRODUCT

};

class ConversionStub: public CodeStub {
 private:
  Bytecodes::Code _bytecode;
  LIR_Opr         _input;
  LIR_Opr         _result;

  static float float_zero;
  static double double_zero;
 public:
  ConversionStub(Bytecodes::Code bytecode, LIR_Opr input, LIR_Opr result)
    : _bytecode(bytecode), _input(input), _result(result) {
  }

  Bytecodes::Code bytecode() { return _bytecode; }
  LIR_Opr         input()    { return _input; }
  LIR_Opr         result()   { return _result; }

  virtual void emit_code(LIR_Assembler* e);
  virtual void visit(LIR_OpVisitState* visitor) {
    visitor->do_slow_case();
    visitor->do_input(_input);
    visitor->do_output(_result);
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("ConversionStub"); }
#endif // PRODUCT
};


// Throws ArrayIndexOutOfBoundsException by default but can be
// configured to throw IndexOutOfBoundsException in constructor
class RangeCheckStub: public CodeStub {
 private:
  CodeEmitInfo* _info;
  LIR_Opr       _index;
  bool          _throw_index_out_of_bounds_exception;

 public:
  RangeCheckStub(CodeEmitInfo* info, LIR_Opr index, bool throw_index_out_of_bounds_exception = false);
  virtual void emit_code(LIR_Assembler* e);
  virtual CodeEmitInfo* info() const             { return _info; }
  virtual bool is_exception_throw_stub() const   { return true; }
  virtual bool is_range_check_stub() const       { return true; }
  virtual void visit(LIR_OpVisitState* visitor) {
    visitor->do_slow_case(_info);
    visitor->do_input(_index);
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("RangeCheckStub"); }
#endif // PRODUCT
};


class DivByZeroStub: public CodeStub {
 private:
  CodeEmitInfo* _info;
  int           _offset;

 public:
  DivByZeroStub(CodeEmitInfo* info)
    : _info(info), _offset(-1) {
  }
  DivByZeroStub(int offset, CodeEmitInfo* info)
    : _info(info), _offset(offset) {
  }
  virtual void emit_code(LIR_Assembler* e);
  virtual CodeEmitInfo* info() const             { return _info; }
  virtual bool is_exception_throw_stub() const   { return true; }
  virtual bool is_divbyzero_stub() const         { return true; }
  virtual void visit(LIR_OpVisitState* visitor) {
    visitor->do_slow_case(_info);
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("DivByZeroStub"); }
#endif // PRODUCT
};


class ImplicitNullCheckStub: public CodeStub {
 private:
  CodeEmitInfo* _info;
  int           _offset;

 public:
  ImplicitNullCheckStub(int offset, CodeEmitInfo* info)
    : _offset(offset), _info(info) {
  }
  virtual void emit_code(LIR_Assembler* e);
  virtual CodeEmitInfo* info() const             { return _info; }
  virtual bool is_exception_throw_stub() const   { return true; }
  virtual void visit(LIR_OpVisitState* visitor) {
    visitor->do_slow_case(_info);
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("ImplicitNullCheckStub"); }
#endif // PRODUCT
};


class NewInstanceStub: public CodeStub {
 private:
  ciInstanceKlass* _klass;
  LIR_Opr          _klass_reg;
  LIR_Opr          _result;
  CodeEmitInfo*    _info;
  Runtime1::StubID _stub_id;

 public:
  NewInstanceStub(LIR_Opr klass_reg, LIR_Opr result, ciInstanceKlass* klass, CodeEmitInfo* info, Runtime1::StubID stub_id);
  virtual void emit_code(LIR_Assembler* e);
  virtual CodeEmitInfo* info() const             { return _info; }
  virtual void visit(LIR_OpVisitState* visitor) {
    visitor->do_slow_case(_info);
    visitor->do_input(_klass_reg);
    visitor->do_output(_result);
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("NewInstanceStub"); }
#endif // PRODUCT
};


class NewTypeArrayStub: public CodeStub {
 private:
  LIR_Opr       _klass_reg;
  LIR_Opr       _length;
  LIR_Opr       _result;
  CodeEmitInfo* _info;

 public:
  NewTypeArrayStub(LIR_Opr klass_reg, LIR_Opr length, LIR_Opr result, CodeEmitInfo* info);
  virtual void emit_code(LIR_Assembler* e);
  virtual CodeEmitInfo* info() const             { return _info; }
  virtual void visit(LIR_OpVisitState* visitor) {
    visitor->do_slow_case(_info);
    visitor->do_input(_klass_reg);
    visitor->do_input(_length);
    assert(_result->is_valid(), "must be valid"); visitor->do_output(_result);
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("NewTypeArrayStub"); }
#endif // PRODUCT
};


class NewObjectArrayStub: public CodeStub {
 private:
  LIR_Opr        _klass_reg;
  LIR_Opr        _length;
  LIR_Opr        _result;
  CodeEmitInfo*  _info;

 public:
  NewObjectArrayStub(LIR_Opr klass_reg, LIR_Opr length, LIR_Opr result, CodeEmitInfo* info);
  virtual void emit_code(LIR_Assembler* e);
  virtual CodeEmitInfo* info() const             { return _info; }
  virtual void visit(LIR_OpVisitState* visitor) {
    visitor->do_slow_case(_info);
    visitor->do_input(_klass_reg);
    visitor->do_input(_length);
    assert(_result->is_valid(), "must be valid"); visitor->do_output(_result);
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("NewObjectArrayStub"); }
#endif // PRODUCT
};


class MonitorAccessStub: public CodeStub {
 protected:
  LIR_Opr _obj_reg;
  LIR_Opr _lock_reg;

 public:
  MonitorAccessStub(LIR_Opr obj_reg, LIR_Opr lock_reg) {
    _obj_reg  = obj_reg;
    _lock_reg  = lock_reg;
  }

#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("MonitorAccessStub"); }
#endif // PRODUCT
};


class MonitorEnterStub: public MonitorAccessStub {
 private:
  CodeEmitInfo* _info;

 public:
  MonitorEnterStub(LIR_Opr obj_reg, LIR_Opr lock_reg, CodeEmitInfo* info);

  virtual void emit_code(LIR_Assembler* e);
  virtual CodeEmitInfo* info() const             { return _info; }
  virtual void visit(LIR_OpVisitState* visitor) {
    visitor->do_input(_obj_reg);
    visitor->do_input(_lock_reg);
    visitor->do_slow_case(_info);
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("MonitorEnterStub"); }
#endif // PRODUCT
};


class MonitorExitStub: public MonitorAccessStub {
 private:
  bool _compute_lock;
  int  _monitor_ix;

 public:
  MonitorExitStub(LIR_Opr lock_reg, bool compute_lock, int monitor_ix)
    : MonitorAccessStub(LIR_OprFact::illegalOpr, lock_reg),
      _compute_lock(compute_lock), _monitor_ix(monitor_ix) { }
  virtual void emit_code(LIR_Assembler* e);
  virtual void visit(LIR_OpVisitState* visitor) {
    assert(_obj_reg->is_illegal(), "unused");
    if (_compute_lock) {
      visitor->do_temp(_lock_reg);
    } else {
      visitor->do_input(_lock_reg);
    }
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("MonitorExitStub"); }
#endif // PRODUCT
};


class PatchingStub: public CodeStub {
 public:
  enum PatchID {
    access_field_id,
    load_klass_id
  };
  enum constants {
    patch_info_size = 3
  };
 private:
  PatchID       _id;
  address       _pc_start;
  int           _bytes_to_copy;
  Label         _patched_code_entry;
  Label         _patch_site_entry;
  Label         _patch_site_continuation;
  Register      _obj;
  CodeEmitInfo* _info;
  int           _oop_index;  // index of the patchable oop in nmethod oop table if needed
  static int    _patch_info_offset;

  void align_patch_site(MacroAssembler* masm);

 public:
  static int patch_info_offset() { return _patch_info_offset; }

  PatchingStub(MacroAssembler* masm, PatchID id, int oop_index = -1):
      _id(id)
    , _info(NULL)
    , _oop_index(oop_index) {
    if (os::is_MP()) {
      // force alignment of patch sites on MP hardware so we
      // can guarantee atomic writes to the patch site.
      align_patch_site(masm);
    }
    _pc_start = masm->pc();
    masm->bind(_patch_site_entry);
  }

  void install(MacroAssembler* masm, LIR_PatchCode patch_code, Register obj, CodeEmitInfo* info) {
    _info = info;
    _obj = obj;
    masm->bind(_patch_site_continuation);
    _bytes_to_copy = masm->pc() - pc_start();
    if (_id == PatchingStub::access_field_id) {
      // embed a fixed offset to handle long patches which need to be offset by a word.
      // the patching code will just add the field offset field to this offset so
      // that we can refernce either the high or low word of a double word field.
      int field_offset = 0;
      switch (patch_code) {
      case lir_patch_low:         field_offset = lo_word_offset_in_bytes; break;
      case lir_patch_high:        field_offset = hi_word_offset_in_bytes; break;
      case lir_patch_normal:      field_offset = 0;                       break;
      default: ShouldNotReachHere();
      }
      NativeMovRegMem* n_move = nativeMovRegMem_at(pc_start());
      n_move->set_offset(field_offset);
    } else if (_id == load_klass_id) {
      assert(_obj != noreg, "must have register object for load_klass");
#ifdef ASSERT
      // verify that we're pointing at a NativeMovConstReg
      nativeMovConstReg_at(pc_start());
#endif
    } else {
      ShouldNotReachHere();
    }
    assert(_bytes_to_copy <= (masm->pc() - pc_start()), "not enough bytes");
  }

  address pc_start() const                       { return _pc_start; }
  PatchID id() const                             { return _id; }

  virtual void emit_code(LIR_Assembler* e);
  virtual CodeEmitInfo* info() const             { return _info; }
  virtual void visit(LIR_OpVisitState* visitor) {
    visitor->do_slow_case(_info);
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("PatchingStub"); }
#endif // PRODUCT
};


//------------------------------------------------------------------------------
// DeoptimizeStub
//
class DeoptimizeStub : public CodeStub {
private:
  CodeEmitInfo* _info;

public:
  DeoptimizeStub(CodeEmitInfo* info) : _info(new CodeEmitInfo(info)) {}

  virtual void emit_code(LIR_Assembler* e);
  virtual CodeEmitInfo* info() const           { return _info; }
  virtual bool is_exception_throw_stub() const { return true; }
  virtual void visit(LIR_OpVisitState* visitor) {
    visitor->do_slow_case(_info);
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("DeoptimizeStub"); }
#endif // PRODUCT
};


class SimpleExceptionStub: public CodeStub {
 private:
  LIR_Opr          _obj;
  Runtime1::StubID _stub;
  CodeEmitInfo*    _info;

 public:
  SimpleExceptionStub(Runtime1::StubID stub, LIR_Opr obj, CodeEmitInfo* info):
    _obj(obj), _info(info), _stub(stub) {
  }

  void set_obj(LIR_Opr obj) {
    _obj = obj;
  }

  virtual void emit_code(LIR_Assembler* e);
  virtual CodeEmitInfo* info() const             { return _info; }
  virtual bool is_exception_throw_stub() const   { return true; }
  virtual void visit(LIR_OpVisitState* visitor) {
    if (_obj->is_valid()) visitor->do_input(_obj);
    visitor->do_slow_case(_info);
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("SimpleExceptionStub"); }
#endif // PRODUCT
};



class ArrayStoreExceptionStub: public SimpleExceptionStub {
 private:
  CodeEmitInfo* _info;

 public:
  ArrayStoreExceptionStub(LIR_Opr obj, CodeEmitInfo* info): SimpleExceptionStub(Runtime1::throw_array_store_exception_id, obj, info) {}
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("ArrayStoreExceptionStub"); }
#endif // PRODUCT
};


class ArrayCopyStub: public CodeStub {
 private:
  LIR_OpArrayCopy* _op;

 public:
  ArrayCopyStub(LIR_OpArrayCopy* op): _op(op) { }

  LIR_Opr src() const                         { return _op->src(); }
  LIR_Opr src_pos() const                     { return _op->src_pos(); }
  LIR_Opr dst() const                         { return _op->dst(); }
  LIR_Opr dst_pos() const                     { return _op->dst_pos(); }
  LIR_Opr length() const                      { return _op->length(); }
  LIR_Opr tmp() const                         { return _op->tmp(); }

  virtual void emit_code(LIR_Assembler* e);
  virtual CodeEmitInfo* info() const          { return _op->info(); }
  virtual void visit(LIR_OpVisitState* visitor) {
    // don't pass in the code emit info since it's processed in the fast path
    visitor->do_slow_case();
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("ArrayCopyStub"); }
#endif // PRODUCT
};

//////////////////////////////////////////////////////////////////////////////////////////
#ifndef SERIALGC

// Code stubs for Garbage-First barriers.
class G1PreBarrierStub: public CodeStub {
 private:
  bool _do_load;
  LIR_Opr _addr;
  LIR_Opr _pre_val;
  LIR_PatchCode _patch_code;
  CodeEmitInfo* _info;

 public:
  // Version that _does_ generate a load of the previous value from addr.
  // addr (the address of the field to be read) must be a LIR_Address
  // pre_val (a temporary register) must be a register;
  G1PreBarrierStub(LIR_Opr addr, LIR_Opr pre_val, LIR_PatchCode patch_code, CodeEmitInfo* info) :
    _addr(addr), _pre_val(pre_val), _do_load(true),
    _patch_code(patch_code), _info(info)
  {
    assert(_pre_val->is_register(), "should be temporary register");
    assert(_addr->is_address(), "should be the address of the field");
  }

  // Version that _does not_ generate load of the previous value; the
  // previous value is assumed to have already been loaded into pre_val.
  G1PreBarrierStub(LIR_Opr pre_val) :
    _addr(LIR_OprFact::illegalOpr), _pre_val(pre_val), _do_load(false),
    _patch_code(lir_patch_none), _info(NULL)
  {
    assert(_pre_val->is_register(), "should be a register");
  }

  LIR_Opr addr() const { return _addr; }
  LIR_Opr pre_val() const { return _pre_val; }
  LIR_PatchCode patch_code() const { return _patch_code; }
  CodeEmitInfo* info() const { return _info; }
  bool do_load() const { return _do_load; }

  virtual void emit_code(LIR_Assembler* e);
  virtual void visit(LIR_OpVisitState* visitor) {
    if (_do_load) {
      // don't pass in the code emit info since it's processed in the fast
      // path
      if (_info != NULL)
        visitor->do_slow_case(_info);
      else
        visitor->do_slow_case();

      visitor->do_input(_addr);
      visitor->do_temp(_pre_val);
    } else {
      visitor->do_slow_case();
      visitor->do_input(_pre_val);
    }
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("G1PreBarrierStub"); }
#endif // PRODUCT
};

// This G1 barrier code stub is used in Unsafe.getObject.
// It generates a sequence of guards around the SATB
// barrier code that are used to detect when we have
// the referent field of a Reference object.
// The first check is assumed to have been generated
// in the code generated for Unsafe.getObject().

class G1UnsafeGetObjSATBBarrierStub: public CodeStub {
 private:
  LIR_Opr _val;
  LIR_Opr _src;

  LIR_Opr _tmp;
  LIR_Opr _thread;

  bool _gen_src_check;

 public:
  // A G1 barrier that is guarded by generated guards that determine whether
  // val (which is the result of Unsafe.getObject() should be recorded in an
  // SATB log buffer. We could be reading the referent field of a Reference object
  // using Unsafe.getObject() and we need to record the referent.
  //
  // * val is the operand returned by the unsafe.getObject routine.
  // * src is the base object
  // * tmp is a temp used to load the klass of src, and then reference type
  // * thread is the thread object.

  G1UnsafeGetObjSATBBarrierStub(LIR_Opr val, LIR_Opr src,
                                LIR_Opr tmp, LIR_Opr thread,
                                bool gen_src_check) :
    _val(val), _src(src),
    _tmp(tmp), _thread(thread),
    _gen_src_check(gen_src_check)
  {
    assert(_val->is_register(), "should have already been loaded");
    assert(_src->is_register(), "should have already been loaded");

    assert(_tmp->is_register(), "should be a temporary register");
  }

  LIR_Opr val() const { return _val; }
  LIR_Opr src() const { return _src; }

  LIR_Opr tmp() const { return _tmp; }
  LIR_Opr thread() const { return _thread; }

  bool gen_src_check() const { return _gen_src_check; }

  virtual void emit_code(LIR_Assembler* e);

  virtual void visit(LIR_OpVisitState* visitor) {
    visitor->do_slow_case();
    visitor->do_input(_val);
    visitor->do_input(_src);
    visitor->do_input(_thread);

    visitor->do_temp(_tmp);
  }

#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("G1UnsafeGetObjSATBBarrierStub"); }
#endif // PRODUCT
};

class G1PostBarrierStub: public CodeStub {
 private:
  LIR_Opr _addr;
  LIR_Opr _new_val;

  static jbyte* _byte_map_base;
  static jbyte* byte_map_base_slow();
  static jbyte* byte_map_base() {
    if (_byte_map_base == NULL) {
      _byte_map_base = byte_map_base_slow();
    }
    return _byte_map_base;
  }

 public:
  // addr (the address of the object head) and new_val must be registers.
  G1PostBarrierStub(LIR_Opr addr, LIR_Opr new_val): _addr(addr), _new_val(new_val) { }

  LIR_Opr addr() const { return _addr; }
  LIR_Opr new_val() const { return _new_val; }

  virtual void emit_code(LIR_Assembler* e);
  virtual void visit(LIR_OpVisitState* visitor) {
    // don't pass in the code emit info since it's processed in the fast path
    visitor->do_slow_case();
    visitor->do_input(_addr);
    visitor->do_input(_new_val);
  }
#ifndef PRODUCT
  virtual void print_name(outputStream* out) const { out->print("G1PostBarrierStub"); }
#endif // PRODUCT
};

#endif // SERIALGC
//////////////////////////////////////////////////////////////////////////////////////////

#endif // SHARE_VM_C1_C1_CODESTUBS_HPP