1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   6  * under the terms of the GNU General Public License version 2 only, as
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  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).
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  24 
  25 #ifndef SHARE_RUNTIME_REGISTERMAP_HPP
  26 #define SHARE_RUNTIME_REGISTERMAP_HPP
  27 
  28 #include "code/vmreg.hpp"
  29 #include "utilities/globalDefinitions.hpp"
  30 #include "utilities/macros.hpp"
  31 
  32 class JavaThread;
  33 
  34 //
  35 // RegisterMap
  36 //
  37 // A companion structure used for stack traversal. The RegisterMap contains
  38 // misc. information needed in order to do correct stack traversal of stack
  39 // frames.  Hence, it must always be passed in as an argument to
  40 // frame::sender(RegisterMap*).
  41 //
  42 // In particular,
  43 //   1) It provides access to the thread for which the stack belongs.  The
  44 //      thread object is needed in order to get sender of a deoptimized frame.
  45 //
  46 //   2) It is used to pass information from a callee frame to its caller
  47 //      frame about how the frame should be traversed.  This is used to let
  48 //      the caller frame take care of calling oops-do of out-going
  49 //      arguments, when the callee frame is not instantiated yet.  This
  50 //      happens, e.g., when a compiled frame calls into
  51 //      resolve_virtual_call.  (Hence, it is critical that the same
  52 //      RegisterMap object is used for the entire stack walk.  Normally,
  53 //      this is hidden by using the StackFrameStream.)  This is used when
  54 //      doing follow_oops and oops_do.
  55 //
  56 //   3) The RegisterMap keeps track of the values of callee-saved registers
  57 //      from frame to frame (hence, the name).  For some stack traversal the
  58 //      values of the callee-saved registers does not matter, e.g., if you
  59 //      only need the static properties such as frame type, pc, and such.
  60 //      Updating of the RegisterMap can be turned off by instantiating the
  61 //      register map as: RegisterMap map(thread, false);
  62 
  63 class RegisterMap : public StackObj {
  64  public:
  65     typedef julong LocationValidType;
  66   enum {
  67     reg_count = ConcreteRegisterImpl::number_of_registers,
  68     location_valid_type_size = sizeof(LocationValidType)*8,
  69     location_valid_size = (reg_count+location_valid_type_size-1)/location_valid_type_size
  70   };
  71  private:
  72   intptr_t*    _location[reg_count];    // Location of registers (intptr_t* looks better than address in the debugger)
  73   LocationValidType _location_valid[location_valid_size];
  74   bool        _include_argument_oops;   // Should include argument_oop marked locations for compiler
  75   JavaThread* _thread;                  // Reference to current thread
  76   bool        _update_map;              // Tells if the register map need to be
  77                                         // updated when traversing the stack
  78 
  79 #ifdef ASSERT
  80   void check_location_valid();
  81 #else
  82   void check_location_valid() {}
  83 #endif
  84 
  85  public:
  86   debug_only(intptr_t* _update_for_id;) // Assert that RegisterMap is not updated twice for same frame
  87   RegisterMap(JavaThread *thread, bool update_map = true);
  88   RegisterMap(const RegisterMap* map);
  89 
  90   address location(VMReg reg) const {
  91     int index = reg->value() / location_valid_type_size;
  92     assert(0 <= reg->value() && reg->value() < reg_count, "range check");
  93     assert(0 <= index && index < location_valid_size, "range check");
  94     if (_location_valid[index] & ((LocationValidType)1 << (reg->value() % location_valid_type_size))) {
  95       return (address) _location[reg->value()];
  96     } else {
  97       return pd_location(reg);
  98     }
  99   }
 100 
 101   void set_location(VMReg reg, address loc) {
 102     int index = reg->value() / location_valid_type_size;
 103     assert(0 <= reg->value() && reg->value() < reg_count, "range check");
 104     assert(0 <= index && index < location_valid_size, "range check");
 105     assert(_update_map, "updating map that does not need updating");
 106     _location[reg->value()] = (intptr_t*) loc;
 107     _location_valid[index] |= ((LocationValidType)1 << (reg->value() % location_valid_type_size));
 108     check_location_valid();
 109   }
 110 
 111   // Called by an entry frame.
 112   void clear();
 113 
 114   bool include_argument_oops() const      { return _include_argument_oops; }
 115   void set_include_argument_oops(bool f)  { _include_argument_oops = f; }
 116 
 117   JavaThread *thread() const { return _thread; }
 118   bool update_map()    const { return _update_map; }
 119 
 120   void print_on(outputStream* st) const;
 121   void print() const;
 122 
 123   // the following contains the definition of pd_xxx methods
 124 #include CPU_HEADER(registerMap)
 125 
 126 };
 127 
 128 #endif // SHARE_RUNTIME_REGISTERMAP_HPP