0 /*                                                                                                                                   
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6  * published by the Free Software Foundation.                                                                                        
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10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License                                                             
11  * version 2 for more details (a copy is included in the LICENSE file that                                                           
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23 
24 #ifndef SHARE_VM_CODE_ICBUFFER_HPP                                                                                                   
25 #define SHARE_VM_CODE_ICBUFFER_HPP                                                                                                   
26 
27 #include "asm/codeBuffer.hpp"                                                                                                        
28 #include "code/stubs.hpp"                                                                                                            
29 #include "interpreter/bytecodes.hpp"                                                                                                 
30 #include "memory/allocation.hpp"                                                                                                     
31 #include "runtime/safepointVerifiers.hpp"                                                                                            
32 #include "utilities/align.hpp"                                                                                                       
33 #include "utilities/debug.hpp"                                                                                                       
34 #include "utilities/macros.hpp"                                                                                                      
35 
36 //                                                                                                                                   
37 // For CompiledIC's:                                                                                                                 
38 //                                                                                                                                   
39 // In cases where we do not have MT-safe state transformation,                                                                       
40 // we go to a transition state, using ICStubs. At a safepoint,                                                                       
41 // the inline caches are transferred from the transitional code:                                                                     
42 //                                                                                                                                   
43 //    instruction_address --> 01 set xxx_oop, Ginline_cache_klass                                                                    
44 //                            23 jump_to Gtemp, yyyy                                                                                 
45 //                            4  nop                                                                                                 
46 
47 class ICStub: public Stub {                                                                                                          
48  private:                                                                                                                            
49   int                 _size;       // total size of the stub incl. code                                                              
50   address             _ic_site;    // points at call instruction of owning ic-buffer                                                 
51   /* stub code follows here */                                                                                                       
52  protected:                                                                                                                          
53   friend class ICStubInterface;                                                                                                      
54   // This will be called only by ICStubInterface                                                                                     
55   void    initialize(int size,                                                                                                       
56                      CodeStrings strings)        { _size = size; _ic_site = NULL; }                                                  
57   void    finalize(); // called when a method is removed                                                                             
58 
59   // General info                                                                                                                    
60   int     size() const                           { return _size; }                                                                   
61   static  int code_size_to_size(int code_size)   { return align_up((int)sizeof(ICStub), CodeEntryAlignment) + code_size; }           
62 
63  public:                                                                                                                             
64   // Creation                                                                                                                        
65   void set_stub(CompiledIC *ic, void* cached_value, address dest_addr);                                                              
66 
67   // Code info                                                                                                                       
68   address code_begin() const                     { return (address)this + align_up(sizeof(ICStub), CodeEntryAlignment); }            
69   address code_end() const                       { return (address)this + size(); }                                                  
70 
71   // Call site info                                                                                                                  
72   address ic_site() const                        { return _ic_site; }                                                                
73   void    clear();                                                                                                                   
74   bool    is_empty() const                       { return _ic_site == NULL; }                                                        
75 
76   // stub info                                                                                                                       
77   address destination() const;  // destination of jump instruction                                                                   
78   void* cached_value() const;   // cached_value for stub                                                                             
79 
80   // Debugging                                                                                                                       
81   void    verify()            PRODUCT_RETURN;                                                                                        
82   void    print()             PRODUCT_RETURN;                                                                                        
83 
84   // Creation                                                                                                                        
85   friend ICStub* ICStub_from_destination_address(address destination_address);                                                       
86 };                                                                                                                                   
87 
88 // ICStub Creation                                                                                                                   
89 inline ICStub* ICStub_from_destination_address(address destination_address) {                                                        
90   ICStub* stub = (ICStub*) (destination_address - align_up(sizeof(ICStub), CodeEntryAlignment));                                     
91   #ifdef ASSERT                                                                                                                      
92   stub->verify();                                                                                                                    
93   #endif                                                                                                                             
94   return stub;                                                                                                                       
95 }                                                                                                                                    
96 
97 #ifdef ASSERT                                                                                                                        
98 // The ICRefillVerifier class is a stack allocated RAII object used to                                                               
99 // detect if a failed IC transition that required IC stub refilling has                                                              
100 // been accidentally missed. It is up to the caller to in that case                                                                  
101 // refill IC stubs.                                                                                                                  
102 class ICRefillVerifier: StackObj {                                                                                                   
103   bool _refill_requested;                                                                                                            
104   bool _refill_remembered;                                                                                                           
105 
106  public:                                                                                                                             
107   ICRefillVerifier();                                                                                                                
108   ~ICRefillVerifier();                                                                                                               
109 
110   void request_refill() { _refill_requested = true; }                                                                                
111   void request_remembered() { _refill_remembered = true; }                                                                           
112 };                                                                                                                                   
113 
114 // The ICRefillVerifierMark is used to set the thread's current                                                                      
115 // ICRefillVerifier to a provided one. This is useful in particular                                                                  
116 // when transitioning IC stubs in parallel and refilling from the                                                                    
117 // master thread invoking the IC stub transitioning code.                                                                            
118 class ICRefillVerifierMark: StackObj {                                                                                               
119 public:                                                                                                                              
120   ICRefillVerifierMark(ICRefillVerifier* verifier);                                                                                  
121   ~ICRefillVerifierMark();                                                                                                           
                                                                                                                                     
                                                                                                                                     
                                                                                                                                     
                                                                                                                                     
                                                                                                                                     
                                                                                                                                     
                                                                                                                                     
                                                                                                                                     
                                                                                                                                     
122 };                                                                                                                                   
123 #endif                                                                                                                               
124 
125 class InlineCacheBuffer: public AllStatic {                                                                                          
126  private:                                                                                                                            
127   // friends                                                                                                                         
128   friend class ICStub;                                                                                                               
129 
130   static int ic_stub_code_size();                                                                                                    
131 
132   static StubQueue* _buffer;                                                                                                         
133 
134   static CompiledICHolder* _pending_released;                                                                                        
135   static int _pending_count;                                                                                                         
136 
137   static StubQueue* buffer()                         { return _buffer;         }                                                     
138 
139   static ICStub* new_ic_stub();                                                                                                      
140 
141   // Machine-dependent implementation of ICBuffer                                                                                    
142   static void    assemble_ic_buffer_code(address code_begin, void* cached_value, address entry_point);                               
143   static address ic_buffer_entry_point  (address code_begin);                                                                        
144   static void*   ic_buffer_cached_value (address code_begin);                                                                        
145 
146  public:                                                                                                                             
147 
148     // Initialization; must be called before first usage                                                                             
149   static void initialize();                                                                                                          
150 
151   // Access                                                                                                                          
152   static bool contains(address instruction_address);                                                                                 
153 
154     // removes the ICStubs after backpatching                                                                                        
155   static void update_inline_caches();                                                                                                
156   static void refill_ic_stubs();                                                                                                     
157 
158   // for debugging                                                                                                                   
159   static bool is_empty();                                                                                                            
160 
161   static void release_pending_icholders();                                                                                           
162   static void queue_for_release(CompiledICHolder* icholder);                                                                         
163   static int pending_icholder_count() { return _pending_count; }                                                                     
164 
165   // New interface                                                                                                                   
166   static bool    create_transition_stub(CompiledIC *ic, void* cached_value, address entry);                                          
167   static address ic_destination_for(CompiledIC *ic);                                                                                 
168   static void*   cached_value_for(CompiledIC *ic);                                                                                   
169 };                                                                                                                                   
170 
171 #endif // SHARE_VM_CODE_ICBUFFER_HPP                                                                                                 
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