1 /*
   2  * Copyright (c) 2002, 2009, 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.
  22  *
  23  */
  24 
  25 #include "incls/_precompiled.incl"
  26 #include "incls/_buildOopMap.cpp.incl"

















  27 
  28 // The functions in this file builds OopMaps after all scheduling is done.
  29 //
  30 // OopMaps contain a list of all registers and stack-slots containing oops (so
  31 // they can be updated by GC).  OopMaps also contain a list of derived-pointer
  32 // base-pointer pairs.  When the base is moved, the derived pointer moves to
  33 // follow it.  Finally, any registers holding callee-save values are also
  34 // recorded.  These might contain oops, but only the caller knows.
  35 //
  36 // BuildOopMaps implements a simple forward reaching-defs solution.  At each
  37 // GC point we'll have the reaching-def Nodes.  If the reaching Nodes are
  38 // typed as pointers (no offset), then they are oops.  Pointers+offsets are
  39 // derived pointers, and bases can be found from them.  Finally, we'll also
  40 // track reaching callee-save values.  Note that a copy of a callee-save value
  41 // "kills" it's source, so that only 1 copy of a callee-save value is alive at
  42 // a time.
  43 //
  44 // We run a simple bitvector liveness pass to help trim out dead oops.  Due to
  45 // irreducible loops, we can have a reaching def of an oop that only reaches
  46 // along one path and no way to know if it's valid or not on the other path.

   1 /*
   2  * Copyright (c) 2002, 2010, 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.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "compiler/oopMap.hpp"
  27 #include "opto/addnode.hpp"
  28 #include "opto/callnode.hpp"
  29 #include "opto/compile.hpp"
  30 #include "opto/machnode.hpp"
  31 #include "opto/matcher.hpp"
  32 #include "opto/phase.hpp"
  33 #include "opto/regalloc.hpp"
  34 #include "opto/rootnode.hpp"
  35 #ifdef TARGET_ARCH_x86
  36 # include "vmreg_x86.inline.hpp"
  37 #endif
  38 #ifdef TARGET_ARCH_sparc
  39 # include "vmreg_sparc.inline.hpp"
  40 #endif
  41 #ifdef TARGET_ARCH_zero
  42 # include "vmreg_zero.inline.hpp"
  43 #endif
  44 
  45 // The functions in this file builds OopMaps after all scheduling is done.
  46 //
  47 // OopMaps contain a list of all registers and stack-slots containing oops (so
  48 // they can be updated by GC).  OopMaps also contain a list of derived-pointer
  49 // base-pointer pairs.  When the base is moved, the derived pointer moves to
  50 // follow it.  Finally, any registers holding callee-save values are also
  51 // recorded.  These might contain oops, but only the caller knows.
  52 //
  53 // BuildOopMaps implements a simple forward reaching-defs solution.  At each
  54 // GC point we'll have the reaching-def Nodes.  If the reaching Nodes are
  55 // typed as pointers (no offset), then they are oops.  Pointers+offsets are
  56 // derived pointers, and bases can be found from them.  Finally, we'll also
  57 // track reaching callee-save values.  Note that a copy of a callee-save value
  58 // "kills" it's source, so that only 1 copy of a callee-save value is alive at
  59 // a time.
  60 //
  61 // We run a simple bitvector liveness pass to help trim out dead oops.  Due to
  62 // irreducible loops, we can have a reaching def of an oop that only reaches
  63 // along one path and no way to know if it's valid or not on the other path.