debugInfoRec.hpp revision 1472:c18cbe5936b8 
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24
25//** The DebugInformationRecorder collects debugging information
26//   for a compiled method.
27//   Debugging information is used for:
28//   - garbage collecting compiled frames
29//   - stack tracing across compiled frames
30//   - deoptimizating compiled frames
31//
32//   The implementation requires the compiler to use the recorder
33//   in the following order:
34//   1) Describe debug information for safepoints at increasing addresses.
35//      a) Add safepoint entry (use add_safepoint or add_non_safepoint)
36//      b) Describe scopes for that safepoint
37//         - create locals if needed (use create_scope_values)
38//         - create expressions if needed (use create_scope_values)
39//         - create monitor stack if needed (use create_monitor_values)
40//         - describe scope (use describe_scope)
41//         "repeat last four steps for all scopes"
42//         "outer most scope first and inner most scope last"
43//         NB: nodes from create_scope_values and create_locations
44//             can be reused for simple sharing.
45//         - mark the end of the scopes (end_safepoint or end_non_safepoint)
46//   2) Use oop_size, data_size, pcs_size to create the nmethod and
47//      finally migrate the debugging information into the nmethod
48//      by calling copy_to.
49
50class DebugToken; // Opaque datatype for stored:
51                  //  - GrowableArray<ScopeValue*>
52                  //  - GrowableArray<MonitorValue*>
53
54// Alias for InvocationEntryBci.
55// Both constants are used for a pseudo-BCI which refers
56// to the state just _before_ a method is entered.
57// SynchronizationEntryBCI is used where the emphasis
58// is on the implicit monitorenter of a synchronized method.
59const int SynchronizationEntryBCI = InvocationEntryBci;
60
61class DIR_Chunk; // private class, a nugget of collected information
62
63class DebugInformationRecorder: public ResourceObj {
64 public:
65  // constructor
66  DebugInformationRecorder(OopRecorder* oop_recorder);
67
68  // adds an oopmap at a specific offset
69  void add_oopmap(int pc_offset, OopMap* map);
70
71  // adds a jvm mapping at pc-offset, for a safepoint only
72  void add_safepoint(int pc_offset, OopMap* map);
73
74  // adds a jvm mapping at pc-offset, for a non-safepoint (profile point)
75  void add_non_safepoint(int pc_offset);
76
77  // Describes debugging information for a scope at the given pc_offset.
78  // Calls must be in non-decreasing order of pc_offset.
79  // If there are several calls at a single pc_offset,
80  // then they occur in the same order as they were performed by the JVM,
81  // with the most recent (innermost) call being described last.
82  // For a safepoint, the pc_offset must have been mentioned
83  // previously by add_safepoint.
84  // Otherwise, the pc_offset must have been mentioned previously
85  // by add_non_safepoint, and the locals, expressions, and monitors
86  // must all be null.
87  void describe_scope(int         pc_offset,
88                      ciMethod*   method,
89                      int         bci,
90                      bool        reexecute,
91                      bool        is_method_handle_invoke = false,
92                      bool        return_oop = false,
93                      DebugToken* locals      = NULL,
94                      DebugToken* expressions = NULL,
95                      DebugToken* monitors    = NULL);
96
97
98  void dump_object_pool(GrowableArray<ScopeValue*>* objects);
99
100  // This call must follow every add_safepoint,
101  // after any intervening describe_scope calls.
102  void end_safepoint(int pc_offset)      { end_scopes(pc_offset, true); }
103  void end_non_safepoint(int pc_offset)  { end_scopes(pc_offset, false); }
104
105  // helper fuctions for describe_scope to enable sharing
106  DebugToken* create_scope_values(GrowableArray<ScopeValue*>* values);
107  DebugToken* create_monitor_values(GrowableArray<MonitorValue*>* monitors);
108
109  // returns the size of the generated scopeDescs.
110  int data_size();
111  int pcs_size();
112  int oop_size() { return oop_recorder()->oop_size(); }
113
114  // copy the generated debugging information to nmethod
115  void copy_to(nmethod* nm);
116
117  // verifies the debug information
118  void verify(const nmethod* code);
119
120  static void print_statistics() PRODUCT_RETURN;
121
122  // Method for setting oopmaps to temporarily preserve old handling of oopmaps
123  OopMapSet *_oopmaps;
124  void set_oopmaps(OopMapSet *oopmaps) { _oopmaps = oopmaps; }
125
126  OopRecorder* oop_recorder() { return _oop_recorder; }
127
128  int last_pc_offset() { return last_pc()->pc_offset(); }
129
130  bool recording_non_safepoints() { return _recording_non_safepoints; }
131
132 private:
133  friend class ScopeDesc;
134  friend class vframeStreamCommon;
135  friend class DIR_Chunk;
136
137  // True if we are recording non-safepoint scopes.
138  // This flag is set if DebugNonSafepoints is true, or if
139  // JVMTI post_compiled_method_load events are enabled.
140  const bool _recording_non_safepoints;
141
142  DebugInfoWriteStream* _stream;
143
144  DebugInfoWriteStream* stream() const { return _stream; }
145
146  OopRecorder* _oop_recorder;
147
148  // Scopes that have been described so far.
149  GrowableArray<DIR_Chunk*>* _all_chunks;
150  GrowableArray<DIR_Chunk*>* _shared_chunks;
151  DIR_Chunk* _next_chunk;
152  DIR_Chunk* _next_chunk_limit;
153
154#ifdef ASSERT
155  enum { rs_null, rs_safepoint, rs_non_safepoint };
156  int _recording_state;
157#endif
158
159  PcDesc* _pcs;
160  int     _pcs_size;
161  int     _pcs_length;
162  // Note:  Would use GrowableArray<PcDesc>, but structs are not supported.
163
164  // PC of most recent real safepoint before the current one,
165  // updated after end_scopes.
166  int _prev_safepoint_pc;
167
168  PcDesc* last_pc() {
169    guarantee(_pcs_length > 0, "a safepoint must be declared already");
170    return &_pcs[_pcs_length-1];
171  }
172  PcDesc* prev_pc() {
173    guarantee(_pcs_length > 1, "a safepoint must be declared already");
174    return &_pcs[_pcs_length-2];
175  }
176  void add_new_pc_offset(int pc_offset);
177  void end_scopes(int pc_offset, bool is_safepoint);
178
179  int  serialize_monitor_values(GrowableArray<MonitorValue*>* monitors);
180  int  serialize_scope_values(GrowableArray<ScopeValue*>* values);
181  int  find_sharable_decode_offset(int stream_offset);
182
183 public:
184  enum { serialized_null = 0 };
185};
186