rts/Globals.c

   1 /* -----------------------------------------------------------------------------
   2  *
   3  * (c) The GHC Team, 1995-2009
   4  *
   5  * The RTS stores some "global" values on behalf of libraries, so that
   6  * some libraries can ensure that certain top-level things are shared
   7  * even when multiple versions of the library are loaded.  e.g. see
   8  * Data.Typeable and GHC.Conc.
   9  *
  10  * How are multiple versions of a library loaded? Examples:
  11  *
  12  *   base - a statically-linked ghci has its own copy, so might libraries it
  13  *          dynamically loads
  14  *
  15  *   libHSghc - a statically-linked ghc has its own copy and so will Core
  16  *              plugins it dynamically loads.
  17  *
  18  * ---------------------------------------------------------------------------*/
  19
  20 #include "PosixSource.h"
  21 #include "Rts.h"
  22
  23 #include "Globals.h"
  24 #include "StablePtr.h"
  25
  26 typedef enum {
  27     GHCConcSignalSignalHandlerStore,
  28     GHCConcWindowsPendingDelaysStore,
  29     GHCConcWindowsIOManagerThreadStore,
  30     GHCConcWindowsProddingStore,
  31     SystemEventThreadEventManagerStore,
  32     SystemEventThreadIOManagerThreadStore,
  33     SystemTimerThreadEventManagerStore,
  34     SystemTimerThreadIOManagerThreadStore,
  35     LibHSghcFastStringTable,
  36     LibHSghcPersistentLinkerState,
  37     LibHSghcInitLinkerDone,
  38     LibHSghcGlobalDynFlags,
  39     LibHSghcStaticOptions,
  40     LibHSghcStaticOptionsReady,
  41     MaxStoreKey
  42 } StoreKey;
  43
  44 #if defined(THREADED_RTS)
  45 Mutex globalStoreLock;
  46 #endif
  47
  48 static StgStablePtr store[MaxStoreKey];
  49
  50 void
  51 initGlobalStore(void)
  52 {
  53     uint32_t i;
  54     for (i=0; i < MaxStoreKey; i++) {
  55         store[i] = 0;
  56     }
  57 #if defined(THREADED_RTS)
  58     initMutex(&globalStoreLock);
  59 #endif
  60 }
  61
  62 void
  63 exitGlobalStore(void)
  64 {
  65     uint32_t i;
  66 #if defined(THREADED_RTS)
  67     closeMutex(&globalStoreLock);
  68 #endif
  69     for (i=0; i < MaxStoreKey; i++) {
  70         if (store[i] != 0) {
  71             freeStablePtr(store[i]);
  72             store[i] = 0;
  73         }
  74     }
  75 }
  76
  77 static StgStablePtr getOrSetKey(StoreKey key, StgStablePtr ptr)
  78 {
  79     StgStablePtr ret = store[key];
  80     if(ret==0) {
  81 #if defined(THREADED_RTS)
  82         ACQUIRE_LOCK(&globalStoreLock);
  83         ret = store[key];
  84         if(ret==0) {
  85 #endif
  86             store[key] = ret = ptr;
  87 #if defined(THREADED_RTS)
  88         }
  89         RELEASE_LOCK(&globalStoreLock);
  90 #endif
  91     }
  92     return ret;
  93 }
  94
  95 #define mkStoreAccessor(name) \
  96     StgStablePtr \
  97     getOrSet##name(StgStablePtr ptr) \
  98     { return getOrSetKey(name, ptr); }
  99
 100 mkStoreAccessor(GHCConcSignalSignalHandlerStore)
 101 mkStoreAccessor(GHCConcWindowsPendingDelaysStore)
 102 mkStoreAccessor(GHCConcWindowsIOManagerThreadStore)
 103 mkStoreAccessor(GHCConcWindowsProddingStore)
 104 mkStoreAccessor(SystemEventThreadEventManagerStore)
 105 mkStoreAccessor(SystemEventThreadIOManagerThreadStore)
 106 mkStoreAccessor(SystemTimerThreadEventManagerStore)
 107 mkStoreAccessor(SystemTimerThreadIOManagerThreadStore)
 108 mkStoreAccessor(LibHSghcFastStringTable)
 109 mkStoreAccessor(LibHSghcPersistentLinkerState)
 110 mkStoreAccessor(LibHSghcInitLinkerDone)
 111 mkStoreAccessor(LibHSghcGlobalDynFlags)
 112 mkStoreAccessor(LibHSghcStaticOptions)
 113 mkStoreAccessor(LibHSghcStaticOptionsReady)