1 /*
   2  * Copyright (c) 1999, 2007, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright 2009 Red Hat, Inc.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 class SharkCodeBuffer : public StackObj {
  27  public:
  28   SharkCodeBuffer(MacroAssembler* masm)
  29     : _masm(masm), _base_pc(NULL) {}
  30 
  31  private:
  32   MacroAssembler* _masm;
  33   llvm::Value*    _base_pc;
  34 
  35  private:
  36   MacroAssembler* masm() const {
  37     return _masm;
  38   }
  39 
  40  public:
  41   llvm::Value* base_pc() const {
  42     return _base_pc;
  43   }
  44   void set_base_pc(llvm::Value* base_pc) {
  45     assert(_base_pc == NULL, "only do this once");
  46     _base_pc = base_pc;
  47   }
  48 
  49   // Allocate some space in the buffer and return its address.
  50   // This buffer will have been relocated by the time the method
  51   // is installed, so you can't inline the result in code.
  52  public:
  53   void* malloc(size_t size) const {
  54     masm()->align(BytesPerWord);
  55     void *result = masm()->pc();
  56     masm()->advance(size);
  57     return result;
  58   }
  59 
  60   // Create a unique offset in the buffer.
  61  public:
  62   int create_unique_offset() const {
  63     int offset = masm()->offset();
  64     masm()->advance(1);
  65     return offset;
  66   }
  67 
  68   // Inline an oop into the buffer and return its offset.
  69  public:
  70   int inline_oop(jobject object) const {
  71     masm()->align(BytesPerWord);
  72     int offset = masm()->offset();
  73     masm()->store_oop(object);
  74     return offset;
  75   }
  76 
  77   // Inline a block of non-oop data into the buffer and return its offset.
  78  public:
  79   int inline_data(void *src, size_t size) const {
  80     masm()->align(BytesPerWord);
  81     int offset = masm()->offset();
  82     void *dst = masm()->pc();
  83     masm()->advance(size);
  84     memcpy(dst, src, size);
  85     return offset;
  86   }
  87 };