libitm/libitm_i.h

   1 /* Copyright (C) 2008, 2009, 2011, 2012 Free Software Foundation, Inc.
   2    Contributed by Richard Henderson <rth@redhat.com>.
   3
   4    This file is part of the GNU Transactional Memory Library (libitm).
   5
   6    Libitm is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    Libitm is distributed in the hope that it will be useful, but WITHOUT ANY
  12    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  13    FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14    more details.
  15
  16    Under Section 7 of GPL version 3, you are granted additional
  17    permissions described in the GCC Runtime Library Exception, version
  18    3.1, as published by the Free Software Foundation.
  19
  20    You should have received a copy of the GNU General Public License and
  21    a copy of the GCC Runtime Library Exception along with this program;
  22    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23    <http://www.gnu.org/licenses/>.  */
  24
  25 /* The following are internal implementation functions and definitions.
  26    To distinguish them from those defined by the Intel ABI, they all
  27    begin with GTM/gtm.  */
  28
  29 #ifndef LIBITM_I_H
  30 #define LIBITM_I_H 1
  31
  32 #include "libitm.h"
  33 #include "config.h"
  34
  35 #include <assert.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <unwind.h>
  39 #include "local_type_traits"
  40 #include "local_atomic"
  41
  42 /* Don't require libgcc_s.so for exceptions.  */
  43 extern void _Unwind_DeleteException (_Unwind_Exception*) __attribute__((weak));
  44
  45
  46 #include "common.h"
  47
  48 namespace GTM HIDDEN {
  49
  50 using namespace std;
  51
  52 // A helper template for accessing an unsigned integral of SIZE bytes.
  53 template<size_t SIZE> struct sized_integral { };
  54 template<> struct sized_integral<1> { typedef uint8_t type; };
  55 template<> struct sized_integral<2> { typedef uint16_t type; };
  56 template<> struct sized_integral<4> { typedef uint32_t type; };
  57 template<> struct sized_integral<8> { typedef uint64_t type; };
  58
  59 typedef unsigned int gtm_word __attribute__((mode (word)));
  60
  61 // These values are given to GTM_restart_transaction and indicate the
  62 // reason for the restart.  The reason is used to decide what STM
  63 // implementation should be used during the next iteration.
  64 enum gtm_restart_reason
  65 {
  66   RESTART_REALLOCATE,
  67   RESTART_LOCKED_READ,
  68   RESTART_LOCKED_WRITE,
  69   RESTART_VALIDATE_READ,
  70   RESTART_VALIDATE_WRITE,
  71   RESTART_VALIDATE_COMMIT,
  72   RESTART_SERIAL_IRR,
  73   RESTART_NOT_READONLY,
  74   RESTART_CLOSED_NESTING,
  75   RESTART_INIT_METHOD_GROUP,
  76   NUM_RESTARTS,
  77   NO_RESTART = NUM_RESTARTS
  78 };
  79
  80 } // namespace GTM
  81
  82 #include "target.h"
  83 #include "rwlock.h"
  84 #include "aatree.h"
  85 #include "cacheline.h"
  86 #include "stmlock.h"
  87 #include "dispatch.h"
  88 #include "containers.h"
  89
  90 namespace GTM HIDDEN {
  91
  92 // This type is private to alloc.c, but needs to be defined so that
  93 // the template used inside gtm_thread can instantiate.
  94 struct gtm_alloc_action
  95 {
  96   void (*free_fn)(void *);
  97   bool allocated;
  98 };
  99
 100 struct gtm_thread;
 101
 102 // A transaction checkpoint: data that has to saved and restored when doing
 103 // closed nesting.
 104 struct gtm_transaction_cp
 105 {
 106   gtm_jmpbuf jb;
 107   size_t undolog_size;
 108   aa_tree<uintptr_t, gtm_alloc_action> alloc_actions;
 109   size_t user_actions_size;
 110   _ITM_transactionId_t id;
 111   uint32_t prop;
 112   uint32_t cxa_catch_count;
 113   void *cxa_unthrown;
 114   // We might want to use a different but compatible dispatch method for
 115   // a nested transaction.
 116   abi_dispatch *disp;
 117   // Nesting level of this checkpoint (1 means that this is a checkpoint of
 118   // the outermost transaction).
 119   uint32_t nesting;
 120
 121   void save(gtm_thread* tx);
 122   void commit(gtm_thread* tx);
 123 };
 124
 125 // An undo log for writes.
 126 struct gtm_undolog
 127 {
 128   vector<gtm_word> undolog;
 129
 130   // Log the previous value at a certain address.
 131   // The easiest way to inline this is to just define this here.
 132   void log(const void *ptr, size_t len)
 133   {
 134     size_t words = (len + sizeof(gtm_word) - 1) / sizeof(gtm_word);
 135     gtm_word *undo = undolog.push(words + 2);
 136     memcpy(undo, ptr, len);
 137     undo[words] = len;
 138     undo[words + 1] = (gtm_word) ptr;
 139   }
 140
 141   void commit () { undolog.clear(); }
 142   size_t size() const { return undolog.size(); }
 143
 144   // In local.cc
 145   void rollback (gtm_thread* tx, size_t until_size = 0);
 146 };
 147
 148 // Contains all thread-specific data required by the entire library.
 149 // This includes all data relevant to a single transaction. Because most
 150 // thread-specific data is about the current transaction, we also refer to
 151 // the transaction-specific parts of gtm_thread as "the transaction" (the
 152 // same applies to names of variables and arguments).
 153 // All but the shared part of this data structure are thread-local data.
 154 // gtm_thread could be split into transaction-specific structures and other
 155 // per-thread data (with those parts then nested in gtm_thread), but this
 156 // would make it harder to later rearrange individual members to optimize data
 157 // accesses. Thus, for now we keep one flat object, and will only split it if
 158 // the code gets too messy.
 159 struct gtm_thread
 160 {
 161
 162   struct user_action
 163   {
 164     _ITM_userCommitFunction fn;
 165     void *arg;
 166     bool on_commit;
 167     _ITM_transactionId_t resuming_id;
 168   };
 169
 170   // The jump buffer by which GTM_longjmp restarts the transaction.
 171   // This field *must* be at the beginning of the transaction.
 172   gtm_jmpbuf jb;
 173
 174   // Data used by local.c for the undo log for both local and shared memory.
 175   gtm_undolog undolog;
 176
 177   // Data used by alloc.c for the malloc/free undo log.
 178   aa_tree<uintptr_t, gtm_alloc_action> alloc_actions;
 179
 180   // Data used by useraction.c for the user-defined commit/abort handlers.
 181   vector<user_action> user_actions;
 182
 183   // A numerical identifier for this transaction.
 184   _ITM_transactionId_t id;
 185
 186   // The _ITM_codeProperties of this transaction as given by the compiler.
 187   uint32_t prop;
 188
 189   // The nesting depth for subsequently started transactions. This variable
 190   // will be set to 1 when starting an outermost transaction.
 191   uint32_t nesting;
 192
 193   // Set if this transaction owns the serial write lock.
 194   // Can be reset only when restarting the outermost transaction.
 195   static const uint32_t STATE_SERIAL            = 0x0001;
 196   // Set if the serial-irrevocable dispatch table is installed.
 197   // Implies that no logging is being done, and abort is not possible.
 198   // Can be reset only when restarting the outermost transaction.
 199   static const uint32_t STATE_IRREVOCABLE       = 0x0002;
 200
 201   // A bitmask of the above.
 202   uint32_t state;
 203
 204   // In order to reduce cacheline contention on global_tid during
 205   // beginTransaction, we allocate a block of 2**N ids to the thread
 206   // all at once.  This number is the next value to be allocated from
 207   // the block, or 0 % 2**N if no such block is allocated.
 208   _ITM_transactionId_t local_tid;
 209
 210   // Data used by eh_cpp.c for managing exceptions within the transaction.
 211   uint32_t cxa_catch_count;
 212   void *cxa_unthrown;
 213   void *eh_in_flight;
 214
 215   // Checkpoints for closed nesting.
 216   vector<gtm_transaction_cp> parent_txns;
 217
 218   // Data used by retry.c for deciding what STM implementation should
 219   // be used for the next iteration of the transaction.
 220   // Only restart_total is reset to zero when the transaction commits, the
 221   // other counters are total values for all previously executed transactions.
 222   uint32_t restart_reason[NUM_RESTARTS];
 223   uint32_t restart_total;
 224
 225   // *** The shared part of gtm_thread starts here. ***
 226   // Shared state is on separate cachelines to avoid false sharing with
 227   // thread-local parts of gtm_thread.
 228
 229   // Points to the next thread in the list of all threads.
 230   gtm_thread *next_thread __attribute__((__aligned__(HW_CACHELINE_SIZE)));
 231
 232   // If this transaction is inactive, shared_state is ~0. Otherwise, this is
 233   // an active or serial transaction.
 234   atomic<gtm_word> shared_state;
 235
 236   // The lock that provides access to serial mode.  Non-serialized
 237   // transactions acquire read locks; a serialized transaction aquires
 238   // a write lock.
 239   static gtm_rwlock serial_lock;
 240
 241   // The head of the list of all threads' transactions.
 242   static gtm_thread *list_of_threads;
 243   // The number of all registered threads.
 244   static unsigned number_of_threads;
 245
 246   // In alloc.cc
 247   void commit_allocations (bool, aa_tree<uintptr_t, gtm_alloc_action>*);
 248   void record_allocation (void *, void (*)(void *));
 249   void forget_allocation (void *, void (*)(void *));
 250   void drop_references_allocations (const void *ptr)
 251   {
 252     this->alloc_actions.erase((uintptr_t) ptr);
 253   }
 254
 255   // In beginend.cc
 256   void rollback (gtm_transaction_cp *cp = 0, bool aborting = false);
 257   bool trycommit ();
 258   void restart (gtm_restart_reason, bool finish_serial_upgrade = false)
 259         ITM_NORETURN;
 260
 261   gtm_thread();
 262   ~gtm_thread();
 263
 264   static void *operator new(size_t);
 265   static void operator delete(void *);
 266
 267   // Invoked from assembly language, thus the "asm" specifier on
 268   // the name, avoiding complex name mangling.
 269 #ifdef __USER_LABEL_PREFIX__
 270 #define UPFX1(t) UPFX(t)
 271 #define UPFX(t) #t
 272   static uint32_t begin_transaction(uint32_t, const gtm_jmpbuf *)
 273         __asm__(UPFX1(__USER_LABEL_PREFIX__) "GTM_begin_transaction") ITM_REGPARM;
 274 #else
 275   static uint32_t begin_transaction(uint32_t, const gtm_jmpbuf *)
 276         __asm__("GTM_begin_transaction") ITM_REGPARM;
 277 #endif
 278   // In eh_cpp.cc
 279   void revert_cpp_exceptions (gtm_transaction_cp *cp = 0);
 280
 281   // In retry.cc
 282   // Must be called outside of transactions (i.e., after rollback).
 283   void decide_retry_strategy (gtm_restart_reason);
 284   abi_dispatch* decide_begin_dispatch (uint32_t prop);
 285   void number_of_threads_changed(unsigned previous, unsigned now);
 286   // Must be called from serial mode. Does not call set_abi_disp().
 287   void set_default_dispatch(abi_dispatch* disp);
 288
 289   // In method-serial.cc
 290   void serialirr_mode ();
 291
 292   // In useraction.cc
 293   void rollback_user_actions (size_t until_size = 0);
 294   void commit_user_actions ();
 295 };
 296
 297 } // namespace GTM
 298
 299 #include "tls.h"
 300
 301 namespace GTM HIDDEN {
 302
 303 // An unscaled count of the number of times we should spin attempting to
 304 // acquire locks before we block the current thread and defer to the OS.
 305 // This variable isn't used when the standard POSIX lock implementations
 306 // are used.
 307 extern uint64_t gtm_spin_count_var;
 308
 309 extern "C" uint32_t GTM_longjmp (uint32_t, const gtm_jmpbuf *, uint32_t)
 310         ITM_NORETURN ITM_REGPARM;
 311
 312 extern "C" void GTM_LB (const void *, size_t) ITM_REGPARM;
 313
 314 extern void GTM_error (const char *fmt, ...)
 315         __attribute__((format (printf, 1, 2)));
 316 extern void GTM_fatal (const char *fmt, ...)
 317         __attribute__((noreturn, format (printf, 1, 2)));
 318
 319 extern abi_dispatch *dispatch_serial();
 320 extern abi_dispatch *dispatch_serialirr();
 321 extern abi_dispatch *dispatch_serialirr_onwrite();
 322 extern abi_dispatch *dispatch_gl_wt();
 323
 324 extern gtm_cacheline_mask gtm_mask_stack(gtm_cacheline *, gtm_cacheline_mask);
 325
 326 } // namespace GTM
 327
 328 #endif // LIBITM_I_H