hphp/runtime/vm/litstr-table.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #ifndef incl_HPHP_LITSTR_TABLE_H_
  18 #define incl_HPHP_LITSTR_TABLE_H_
  19
  20 #include "hphp/runtime/base/string-hash-map.h"
  21 #include "hphp/runtime/vm/named-entity.h"
  22 #include "hphp/runtime/vm/named-entity-pair-table.h"
  23 #include "hphp/util/alloc.h"
  24 #include "hphp/util/functional.h"
  25 #include "hphp/util/hash-map.h"
  26 #include "hphp/util/mutex.h"
  27
  28 #include <tbb/concurrent_hash_map.h>
  29
  30 namespace HPHP {
  31 ///////////////////////////////////////////////////////////////////////////////
  32
  33 struct StringData;
  34
  35 ///////////////////////////////////////////////////////////////////////////////
  36
  37 /*
  38  * Global litstr Id's are all above this mark.
  39  */
  40 constexpr int kGlobalLitstrOffset = 0x40000000;
  41
  42 ///////////////////////////////////////////////////////////////////////////////
  43
  44 /*
  45  * Singleton global table of literal strings and NamedEntitys.
  46  *
  47  * This can only be safely used when the repo is built in WholeProgram mode and
  48  * run in RepoAuthoritative mode.
  49  */
  50 struct LitstrTable {
  51
  52   /////////////////////////////////////////////////////////////////////////////
  53   // Singleton init and get.                                           [static]
  54
  55   /*
  56    * Create the singleton LitstrTable.
  57    *
  58    * Must not be called in concurrent contexts---the table pointer is not
  59    * atomic, and init() does not check if a table already exists.
  60    */
  61   static void init();
  62
  63   /*
  64    * Destroy the singleton LitstrTable.
  65    *
  66    * Must not be called in concurrent contexts---the table pointer is not
  67    * atomic.
  68    */
  69   static void fini();
  70
  71   /*
  72    * Get the singleton LitstrTable.
  73    */
  74   static LitstrTable& get();
  75
  76
  77   /////////////////////////////////////////////////////////////////////////////
  78   // Main API.
  79
  80   /*
  81    * Size of the table.
  82    */
  83   size_t numLitstrs() const;
  84
  85   /*
  86    * Dispatch to corresponding NamedEntityPairTable methods, sans `Id' suffix.
  87    */
  88   bool contains(Id id) const;
  89   StringData* lookupLitstrId(Id id) const;
  90   const NamedEntity* lookupNamedEntityId(Id id) const;
  91   NamedEntityPair lookupNamedEntityPairId(Id id) const;
  92
  93   static bool canRead() {
  94     return !s_litstrTable || s_litstrTable->m_safeToRead;
  95   }
  96
  97   /*
  98    * Set up the named info table.  Not thread-safe.
  99    */
 100   void setNamedEntityPairTable(NamedEntityPairTable&& namedInfo);
 101
 102   /*
 103    * Add an entry for `litstr' to the table.
 104    *
 105    * The "merge" terminology is inherited from Unit.
 106    */
 107   Id mergeLitstr(const StringData* litstr);
 108
 109   /*
 110    * Call onItem() for each item in the table.
 111    */
 112   void forEachLitstr(
 113     std::function<void (int i, const StringData* name)> onItem);
 114
 115
 116   /////////////////////////////////////////////////////////////////////////////
 117   // Concurrency control.
 118
 119   /*
 120    * LitstrTable reader/writer state.
 121    *
 122    * Setting the reader state will update m_namedInfo from m_litstr2id.
 123    */
 124   void setReading();
 125   void setWriting();
 126
 127
 128   /////////////////////////////////////////////////////////////////////////////
 129   // Private constructor.
 130
 131 private:
 132   LitstrTable() {}
 133
 134
 135   /////////////////////////////////////////////////////////////////////////////
 136   // Data members.
 137
 138 private:
 139   static LitstrTable* s_litstrTable;
 140
 141   using LitstrMap = tbb::concurrent_hash_map<
 142     const StringData*,
 143     Id,
 144     StringDataHashCompare,
 145     VMAllocator<char>
 146   >;
 147
 148   NamedEntityPairTable m_namedInfo;
 149   LitstrMap m_litstr2id;
 150
 151   std::atomic<Id> m_nextId{1};
 152   std::atomic<bool> m_safeToRead{true};
 153 };
 154
 155 ///////////////////////////////////////////////////////////////////////////////
 156 // ID helpers.
 157
 158 /*
 159  * Functions for differentiating global litstrId's from unit-local Id's.
 160  */
 161 bool isGlobalLitstrId(Id id);
 162 Id encodeGlobalLitstrId(Id id);
 163 Id decodeGlobalLitstrId(Id id);
 164
 165 ///////////////////////////////////////////////////////////////////////////////
 166 }
 167
 168 #define incl_HPHP_LITSTR_TABLE_INL_H_
 169 #include "hphp/runtime/vm/litstr-table-inl.h"
 170 #undef incl_HPHP_LITSTR_TABLE_INL_H_
 171
 172 #endif // incl_HPHP_LITSTR_TABLE_H_