scopeDesc.hpp

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/* Copyright 1994 - 1996, LongView Technologies L.L.C. $Revision: 1.42 $ */
/* Copyright (c) 2006, Sun Microsystems, Inc.
All rights reserved.

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#ifdef DELTA_COMPILER

class NameDescClosure {
 public:
  virtual void arg          (int no, NameDesc* a, char* pc) {}
  virtual void temp         (int no, NameDesc* t, char* pc) {}
  virtual void context_temp (int no, NameDesc* c, char* pc) {}
  virtual void stack_expr   (int no, NameDesc* e, char* pc) {}
};


const int16 IllegalBCI  =    -1;
const int16 PrologueBCI =     0;
const int16 EpilogueBCI = 32766;

// use the following functions to compare bcis; they handle PrologueBCI et al.
// negative if bci1 is before bci2, 0 if same, positive if after
int compareBCI(int bci1, int bci2);

inline bool bciLT(int bci1, int bci2) { return compareBCI(bci1, bci2) <  0; }
inline bool bciLE(int bci1, int bci2) { return compareBCI(bci1, bci2) <= 0; }
inline bool bciGT(int bci1, int bci2) { return compareBCI(bci1, bci2) >  0; }
inline bool bciGE(int bci1, int bci2) { return compareBCI(bci1, bci2) >= 0; }

// Blocks belonging to scopes that aren't described (because they
// can't possibly be visible to the user) get IllegalDescOffset as
// their desc offset
const int IllegalDescOffset = -2;


// scopeDescs contain the information that makes source-level debugging of
// nmethods possible; each scopeDesc describes a method activation
// Class Hierarchy:
//  - ScopeDesc          (abstract)
//    - MethodScopeDesc
//    - BlockScopeDesc
//    - TopLevelScopeDesc
//  - NonInlinedBlockScopeDesc

class ScopeDesc : public PrintableResourceObj {         // abstract
 protected:
  // Creation information
  const nmethodScopes* _scopes;
  int                  _offset;
  char*                _pc;

 protected:
  // Cached information
  bool      _has_temps;
  bool      _has_context_temps;
  bool      _has_expr_stack;
  methodOop _method;
  int       _scopeID;
  bool      _lite;
  int       _senderScopeOffset;
  int       _senderByteCodeIndex;
  bool      _allocates_compiled_context;
  int       _name_desc_offset;
  int       _next;

  // If the pc of a scopeDesc is equal to invalid_pc, the scopeDesc is pc independent.
  // A pc independent scopeDesc prints out all the locations for its nameDescs.
  // NB: Only relevant for new backend.
  static char* invalid_pc;

 public:
  void iterate    (NameDescClosure* blk);       // info for given pc()
  void iterate_all(NameDescClosure* blk);       // info for all pc's
  
  NameDesc* nameDescAt(int& offset) const;
  int       valueAt(int& offset) const;

  ScopeDesc(const nmethodScopes* scopes, int offset, char* pc);

  int   offset() const                          { return int(_offset); }
  char* pc()     const                          { return _pc; } 

  bool is_equal(ScopeDesc* s) const {
    return    _scopes == s->_scopes
           && _offset == s->_offset;
  }

  // A lite scopeDesc has no information saved on temporaries or expression stack.
  bool          is_lite() const                 { return _lite; }
  bool          allocates_interpreted_context() const;
  methodOop     method() const                  { return _method; }

  // Tells whether a compiled context is allocated for this scope.
  bool          allocates_compiled_context() const { return _allocates_compiled_context; }

  // Returns the name desc for the allocated compiled context.
  NameDesc*     compiled_context();

  int           scopeID() const                 { return _scopeID; }
  const nmethodScopes* scopes() const           { return _scopes; }
  symbolOop     selector() const                { return method()->selector(); }
  ScopeDesc*    sender() const;
  virtual klassOop selfKlass() const            = 0;

  // Returns the parent scope
  // If cross_nmethod_boundary is false parent will return NULL if
  // the parent is located in another compilation unit (nmethod).
  virtual ScopeDesc* parent(bool cross_nmethod_boundary = false) const = 0;
  ScopeDesc* home(bool cross_nmethod_boundary = false) const;
  
  // Returns the bci of the calling method if this scopeDesc is inlined.
  // For a root scopeDesc IllegalBCI is returned.
  int senderBCI() const {
    assert(_senderByteCodeIndex != IllegalBCI,
           "need to ask calling byte code");
    return _senderByteCodeIndex; }
  
  // Root scope?
  bool isTop() const                            { return _senderScopeOffset == 0; }

  // Lookup key
  virtual LookupKey* key() const                = 0;

  // scope equivalence -- for compiler
  virtual bool s_equivalent(ScopeDesc* s) const;
  virtual bool l_equivalent(LookupKey* s) const;
  
  // types test operations
  virtual bool isMethodScope() const            { return false; }
  virtual bool isBlockScope() const             { return false; }
  virtual bool isTopLevelBlockScope() const     { return false; }
  virtual bool isNonInlinedBlockScope() const   { return false; }

  virtual NameDesc* self() const                = NULL;
  NameDesc* temporary       (int index, bool canFail = false);
  NameDesc* contextTemporary(int index, bool canFail = false);
  NameDesc* exprStackElem   (int bci, bool includeTrivial = true);

 public:
  int next_offset() const                       { return _next; } 
  int sender_scope_offset() const               { return _offset - _senderScopeOffset; }

  bool verify();
  void verify_expression_stack(int bci);

  // printing support
  void print(int indent, bool all_pcs);         // print info for current/all pc's
  void print()                                  { print(0, false); }
  virtual void print_value_on(outputStream* st) const;

 protected:
  virtual bool shallow_verify()                 { return true; }
  virtual void printName() = 0;
  virtual void printSelf() {}

 public:
  Expr* selfExpr(PReg* p) const;                // Type information for the optimizing compiler

  friend nmethodScopes;
  friend NonInlinedBlockScopeDesc;
};


class MethodScopeDesc : public ScopeDesc {
 protected:
  // Cached information
  LookupKey _key;
  NameDesc* _self_name;

 public:
  MethodScopeDesc(const nmethodScopes* scopes, int offset, char* pc); 
  bool s_equivalent(ScopeDesc* s) const;
  bool l_equivalent(LookupKey* s) const;

  bool isMethodScope() const                    { return true; }

  NameDesc* self() const                        { return _self_name; }
  LookupKey* key() const                        { return (LookupKey*)&_key; }
  klassOop selfKlass() const                    { return _key.klass(); }

  ScopeDesc* parent(bool cross_nmethod_boundary = false) const { return NULL; }
  
  // printing support
  void printName();
  void printSelf();
  void print_value_on(outputStream* st) const;
};

// an inlined block whose parent scope is in the same nmethod
class BlockScopeDesc : public ScopeDesc {
 protected:
  // Cached information
  int _parentScopeOffset;

 public:
  BlockScopeDesc(const nmethodScopes* scopes, int offset, char* pc);
 
  // NB: the next three operations may return NULL (no context)
  klassOop   selfKlass() const;         
  NameDesc*  self() const;
  ScopeDesc* parent(bool cross_nmethod_boundary = false) const;

  LookupKey* key() const;
  
  bool s_equivalent(ScopeDesc* s) const;

  bool isBlockScope() const                     { return true; }
  
  // print operations
  void printSelf();
  void printName();
  void print_value_on(outputStream* st) const;
};

// A block method whose enclosing scope isn't in the same nmethod.
// Must be a root scope.
class TopLevelBlockScopeDesc : public ScopeDesc {
 protected:
  // Cached information
  NameDesc* _self_name;
  klassOop  _self_klass;

 public:
  TopLevelBlockScopeDesc(const nmethodScopes* scopes, int offset, char* pc);

  // type test operations
  bool isBlockScope() const                     { return true; }
  bool isTopLevelBlockScope() const             { return true; }

  klassOop selfKlass() const                    { return _self_klass; }
  NameDesc* self() const                        { return _self_name; }
  // NB: parent() may return NULL for clean blocks 
  ScopeDesc* parent(bool cross_nmethod_boundary = false) const; 

  LookupKey* key() const;
  
  bool s_equivalent(ScopeDesc* s) const;

  // print operations
  void printSelf();
  void printName();
  void print_value_on(outputStream* st) const;
};

class NonInlinedBlockScopeDesc : public PrintableResourceObj {
 protected:
  // Creation information
  const nmethodScopes* _scopes;
  int                  _offset;

 protected:
  // Cached information
  methodOop _method;
  int       _parentScopeOffset;
  
 public:
  NonInlinedBlockScopeDesc(const nmethodScopes* scopes, int offset);

  methodOop  method() const { return _method; }
  ScopeDesc* parent() const;
  void       print();
};

#endif

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