1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   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.
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  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).
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  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  20  * or visit www.oracle.com if you need additional information or have any
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  24 
  25 #ifndef SHARE_VM_CODE_CODECACHE_HPP
  26 #define SHARE_VM_CODE_CODECACHE_HPP
  27 
  28 #include "code/codeBlob.hpp"
  29 #include "code/nmethod.hpp"
  30 #include "memory/allocation.hpp"
  31 #include "memory/heap.hpp"
  32 #include "oops/instanceKlass.hpp"
  33 #include "oops/oopsHierarchy.hpp"
  34 #include "runtime/mutexLocker.hpp"
  35 
  36 // The CodeCache implements the code cache for various pieces of generated
  37 // code, e.g., compiled java methods, runtime stubs, transition frames, etc.
  38 // The entries in the CodeCache are all CodeBlob's.
  39 
  40 // -- Implementation --
  41 // The CodeCache consists of one or more CodeHeaps, each of which contains
  42 // CodeBlobs of a specific CodeBlobType. Currently heaps for the following
  43 // types are available:
  44 //  - Non-nmethods: Non-nmethods like Buffers, Adapters and Runtime Stubs
  45 //  - Profiled nmethods: nmethods that are profiled, i.e., those
  46 //    executed at level 2 or 3
  47 //  - Non-Profiled nmethods: nmethods that are not profiled, i.e., those
  48 //    executed at level 1 or 4 and native methods
  49 //  - All: Used for code of all types if code cache segmentation is disabled.
  50 //
  51 // In the rare case of the non-nmethod code heap getting full, non-nmethod code
  52 // will be stored in the non-profiled code heap as a fallback solution.
  53 //
  54 // Depending on the availability of compilers and TieredCompilation there
  55 // may be fewer heaps. The size of the code heaps depends on the values of
  56 // ReservedCodeCacheSize, NonProfiledCodeHeapSize and ProfiledCodeHeapSize
  57 // (see CodeCache::heap_available(..) and CodeCache::initialize_heaps(..)
  58 // for details).
  59 //
  60 // Code cache segmentation is controlled by the flag SegmentedCodeCache.
  61 // If turned off, all code types are stored in a single code heap. By default
  62 // code cache segmentation is turned on if TieredCompilation is enabled and
  63 // ReservedCodeCacheSize >= 240 MB.
  64 //
  65 // All methods of the CodeCache accepting a CodeBlobType only apply to
  66 // CodeBlobs of the given type. For example, iteration over the
  67 // CodeBlobs of a specific type can be done by using CodeCache::first_blob(..)
  68 // and CodeCache::next_blob(..) and providing the corresponding CodeBlobType.
  69 //
  70 // IMPORTANT: If you add new CodeHeaps to the code cache or change the
  71 // existing ones, make sure to adapt the dtrace scripts (jhelper.d) for
  72 // Solaris and BSD.
  73 
  74 class OopClosure;
  75 class DepChange;
  76 
  77 class CodeCache : AllStatic {
  78   friend class VMStructs;
  79   friend class NMethodIterator;
  80   friend class WhiteBox;
  81  private:
  82   // CodeHeaps of the cache
  83   static GrowableArray<CodeHeap*>* _heaps;
  84 
  85   static address _low_bound;                            // Lower bound of CodeHeap addresses
  86   static address _high_bound;                           // Upper bound of CodeHeap addresses
  87   static int _number_of_blobs;                          // Total number of CodeBlobs in the cache
  88   static int _number_of_adapters;                       // Total number of Adapters in the cache
  89   static int _number_of_nmethods;                       // Total number of nmethods in the cache
  90   static int _number_of_nmethods_with_dependencies;     // Total number of nmethods with dependencies
  91   static bool _needs_cache_clean;                       // True if inline caches of the nmethods needs to be flushed
  92   static nmethod* _scavenge_root_nmethods;              // linked via nm->scavenge_root_link()
  93   static int _codemem_full_count;                       // Number of times a CodeHeap in the cache was full
  94 
  95   static void mark_scavenge_root_nmethods() PRODUCT_RETURN;
  96   static void verify_perm_nmethods(CodeBlobClosure* f_or_null) PRODUCT_RETURN;
  97 
  98   // CodeHeap management
  99   static void initialize_heaps();                             // Initializes the CodeHeaps
 100   // Creates a new heap with the given name and size, containing CodeBlobs of the given type
 101   static void add_heap(ReservedSpace rs, const char* name, int code_blob_type);
 102   static CodeHeap* get_code_heap(const CodeBlob* cb);         // Returns the CodeHeap for the given CodeBlob
 103   static CodeHeap* get_code_heap(int code_blob_type);         // Returns the CodeHeap for the given CodeBlobType
 104   // Returns the name of the VM option to set the size of the corresponding CodeHeap
 105   static const char* get_code_heap_flag_name(int code_blob_type);
 106   static bool heap_available(int code_blob_type);             // Returns true if an own CodeHeap for the given CodeBlobType is available
 107   static size_t heap_alignment();                             // Returns the alignment of the CodeHeaps in bytes
 108   static ReservedCodeSpace reserve_heap_memory(size_t size);  // Reserves one continuous chunk of memory for the CodeHeaps
 109 
 110   // Iteration
 111   static CodeBlob* first_blob(CodeHeap* heap);                // Returns the first CodeBlob on the given CodeHeap
 112   static CodeBlob* first_blob(int code_blob_type);            // Returns the first CodeBlob of the given type
 113   static CodeBlob* next_blob(CodeHeap* heap, CodeBlob* cb);   // Returns the first alive CodeBlob on the given CodeHeap
 114   static CodeBlob* next_blob(CodeBlob* cb);                   // Returns the next CodeBlob of the given type succeeding the given CodeBlob
 115 
 116   static size_t bytes_allocated_in_freelists();
 117   static int    allocated_segments();
 118   static size_t freelists_length();
 119 
 120  public:
 121   // Initialization
 122   static void initialize();
 123 
 124   // Allocation/administration
 125   static CodeBlob* allocate(int size, int code_blob_type, bool strict = false); // allocates a new CodeBlob
 126   static void commit(CodeBlob* cb);                        // called when the allocated CodeBlob has been filled
 127   static int  alignment_unit();                            // guaranteed alignment of all CodeBlobs
 128   static int  alignment_offset();                          // guaranteed offset of first CodeBlob byte within alignment unit (i.e., allocation header)
 129   static void free(CodeBlob* cb);                          // frees a CodeBlob
 130   static bool contains(void *p);                           // returns whether p is included
 131   static void blobs_do(void f(CodeBlob* cb));              // iterates over all CodeBlobs
 132   static void blobs_do(CodeBlobClosure* f);                // iterates over all CodeBlobs
 133   static void nmethods_do(void f(nmethod* nm));            // iterates over all nmethods
 134   static void alive_nmethods_do(void f(nmethod* nm));      // iterates over all alive nmethods
 135 
 136   // Lookup
 137   static CodeBlob* find_blob(void* start);              // Returns the CodeBlob containing the given address
 138   static CodeBlob* find_blob_unsafe(void* start);       // Same as find_blob but does not fail if looking up a zombie method
 139   static nmethod*  find_nmethod(void* start);           // Returns the nmethod containing the given address
 140 
 141   static int       nof_blobs()      { return _number_of_blobs; }      // Returns the total number of CodeBlobs in the cache
 142   static int       nof_adapters()   { return _number_of_adapters; }   // Returns the total number of Adapters in the cache
 143   static int       nof_nmethods()   { return _number_of_nmethods; }   // Returns the total number of nmethods in the cache
 144 
 145   // GC support
 146   static void gc_epilogue();
 147   static void gc_prologue();
 148   static void verify_oops();
 149   // If "unloading_occurred" is true, then unloads (i.e., breaks root links
 150   // to) any unmarked codeBlobs in the cache.  Sets "marked_for_unloading"
 151   // to "true" iff some code got unloaded.
 152   static void do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred);
 153   static void asserted_non_scavengable_nmethods_do(CodeBlobClosure* f = NULL) PRODUCT_RETURN;
 154   static void scavenge_root_nmethods_do(CodeBlobClosure* f);
 155 
 156   static nmethod* scavenge_root_nmethods()            { return _scavenge_root_nmethods; }
 157   static void set_scavenge_root_nmethods(nmethod* nm) { _scavenge_root_nmethods = nm; }
 158   static void add_scavenge_root_nmethod(nmethod* nm);
 159   static void drop_scavenge_root_nmethod(nmethod* nm);
 160   static void prune_scavenge_root_nmethods();
 161 
 162   // Printing/debugging
 163   static void print();                           // prints summary
 164   static void print_internals();
 165   static void print_memory_overhead();
 166   static void verify();                          // verifies the code cache
 167   static void print_trace(const char* event, CodeBlob* cb, int size = 0) PRODUCT_RETURN;
 168   static void print_summary(outputStream* st, bool detailed = true); // Prints a summary of the code cache usage
 169   static void log_state(outputStream* st);
 170   static const char* get_code_heap_name(int code_blob_type)  { return (heap_available(code_blob_type) ? get_code_heap(code_blob_type)->name() : "Unused"); }
 171   static void report_codemem_full(int code_blob_type, bool print);
 172 
 173   // Dcmd (Diagnostic commands)
 174   static void print_codelist(outputStream* st);
 175   static void print_layout(outputStream* st);
 176 
 177   // The full limits of the codeCache
 178   static address low_bound()                          { return _low_bound; }
 179   static address high_bound()                         { return _high_bound; }
 180 
 181   // Profiling
 182   static size_t capacity();
 183   static size_t unallocated_capacity(int code_blob_type);
 184   static size_t unallocated_capacity();
 185   static size_t max_capacity();
 186 
 187   static double reverse_free_ratio(int code_blob_type);
 188 
 189   static bool needs_cache_clean()                     { return _needs_cache_clean; }
 190   static void set_needs_cache_clean(bool v)           { _needs_cache_clean = v;    }
 191   static void clear_inline_caches();                  // clear all inline caches
 192 
 193   // Returns the CodeBlobType for the given nmethod
 194   static int get_code_blob_type(nmethod* nm) {
 195     return get_code_heap(nm)->code_blob_type();
 196   }
 197 
 198   // Returns the CodeBlobType for the given compilation level
 199   static int get_code_blob_type(int comp_level) {
 200     if (comp_level == CompLevel_none ||
 201         comp_level == CompLevel_simple ||
 202         comp_level == CompLevel_full_optimization) {
 203       // Non profiled methods
 204       return CodeBlobType::MethodNonProfiled;
 205     } else if (comp_level == CompLevel_limited_profile ||
 206                comp_level == CompLevel_full_profile) {
 207       // Profiled methods
 208       return CodeBlobType::MethodProfiled;
 209     }
 210     ShouldNotReachHere();
 211     return 0;
 212   }
 213 
 214   static void verify_clean_inline_caches();
 215   static void verify_icholder_relocations();
 216 
 217   // Deoptimization
 218  private:
 219   static int  mark_for_deoptimization(DepChange& changes);
 220 #ifdef HOTSWAP
 221   static int  mark_for_evol_deoptimization(instanceKlassHandle dependee);
 222 #endif // HOTSWAP
 223 
 224  public:
 225   static void mark_all_nmethods_for_deoptimization();
 226   static int  mark_for_deoptimization(Method* dependee);
 227   static void make_marked_nmethods_zombies();
 228   static void make_marked_nmethods_not_entrant();
 229 
 230   // Flushing and deoptimization
 231   static void flush_dependents_on(instanceKlassHandle dependee);
 232   static void flush_dependents_on(Handle call_site, Handle method_handle);
 233 #ifdef HOTSWAP
 234   // Flushing and deoptimization in case of evolution
 235   static void flush_evol_dependents_on(instanceKlassHandle dependee);
 236 #endif // HOTSWAP
 237   // Support for fullspeed debugging
 238   static void flush_dependents_on_method(methodHandle dependee);
 239 
 240   // tells how many nmethods have dependencies
 241   static int number_of_nmethods_with_dependencies();
 242 
 243   static int get_codemem_full_count() { return _codemem_full_count; }
 244 };
 245 
 246 
 247 // Iterator to iterate over nmethods in the CodeCache.
 248 class NMethodIterator : public StackObj {
 249  private:
 250   CodeBlob* _code_blob;   // Current CodeBlob
 251   int _code_blob_type;    // Refers to current CodeHeap
 252 
 253  public:
 254   NMethodIterator() {
 255     initialize(NULL); // Set to NULL, initialized by first call to next()
 256   }
 257 
 258   NMethodIterator(nmethod* nm) {
 259     initialize(nm);
 260   }
 261 
 262   // Advance iterator to next nmethod
 263   bool next() {
 264     assert_locked_or_safepoint(CodeCache_lock);
 265     assert(_code_blob_type < CodeBlobType::NumTypes, "end reached");
 266 
 267     bool result = next_nmethod();
 268     while (!result && (_code_blob_type < CodeBlobType::MethodProfiled)) {
 269       // Advance to next code heap if segmented code cache
 270       _code_blob_type++;
 271       result = next_nmethod();
 272     }
 273     return result;
 274   }
 275 
 276   // Advance iterator to next alive nmethod
 277   bool next_alive() {
 278     bool result = next();
 279     while(result && !_code_blob->is_alive()) {
 280       result = next();
 281     }
 282     return result;
 283   }
 284 
 285   bool end()        const   { return _code_blob == NULL; }
 286   nmethod* method() const   { return (nmethod*)_code_blob; }
 287 
 288 private:
 289   // Initialize iterator to given nmethod
 290   void initialize(nmethod* nm) {
 291     _code_blob = (CodeBlob*)nm;
 292     if (!SegmentedCodeCache) {
 293       // Iterate over all CodeBlobs
 294       _code_blob_type = CodeBlobType::All;
 295     } else if (nm != NULL) {
 296       _code_blob_type = CodeCache::get_code_blob_type(nm);
 297     } else {
 298       // Only iterate over method code heaps, starting with non-profiled
 299       _code_blob_type = CodeBlobType::MethodNonProfiled;
 300     }
 301   }
 302 
 303   // Advance iterator to the next nmethod in the current code heap
 304   bool next_nmethod() {
 305     // Get first method CodeBlob
 306     if (_code_blob == NULL) {
 307       _code_blob = CodeCache::first_blob(_code_blob_type);
 308       if (_code_blob == NULL) {
 309         return false;
 310       } else if (_code_blob->is_nmethod()) {
 311         return true;
 312       }
 313     }
 314     // Search for next method CodeBlob
 315     _code_blob = CodeCache::next_blob(_code_blob);
 316     while (_code_blob != NULL && !_code_blob->is_nmethod()) {
 317       _code_blob = CodeCache::next_blob(_code_blob);
 318     }
 319     return _code_blob != NULL;
 320   }
 321 };
 322 
 323 #endif // SHARE_VM_CODE_CODECACHE_HPP