gcc/timevar.h

   1 /* Timing variables for measuring compiler performance.
   2    Copyright (C) 2000-2024 Free Software Foundation, Inc.
   3    Contributed by Alex Samuel <samuel@codesourcery.com>
   4
   5    This file is part of GCC.
   6
   7    GCC is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3, or (at your option)
  10    any later version.
  11
  12    GCC is distributed in the hope that it will be useful, but WITHOUT
  13    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  15    License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GCC; see the file COPYING3.  If not see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef GCC_TIMEVAR_H
  22 #define GCC_TIMEVAR_H
  23
  24 namespace json { class value; }
  25
  26 /* Timing variables are used to measure elapsed time in various
  27    portions of the compiler.  Each measures elapsed user, system, and
  28    wall-clock time, as appropriate to and supported by the host
  29    system.
  30
  31    Timing variables are defined using the DEFTIMEVAR macro in
  32    timevar.def.  Each has an enumeral identifier, used when referring
  33    to the timing variable in code, and a character string name.
  34
  35    Timing variables can be used in two ways:
  36
  37      - On the timing stack, using timevar_push and timevar_pop.
  38        Timing variables may be pushed onto the stack; elapsed time is
  39        attributed to the topmost timing variable on the stack.  When
  40        another variable is pushed on, the previous topmost variable is
  41        `paused' until the pushed variable is popped back off.
  42
  43      - As a standalone timer, using timevar_start and timevar_stop.
  44        All time elapsed between the two calls is attributed to the
  45        variable.
  46 */
  47
  48 /* This structure stores the various varieties of time that can be
  49    measured.  Times are stored in nanoseconds.  The time may be an
  50    absolute time or a time difference; in the former case, the time
  51    base is undefined, except that the difference between two times
  52    produces a valid time difference.  */
  53
  54 struct timevar_time_def
  55 {
  56   /* User time in this process.  */
  57   uint64_t user;
  58
  59   /* System time (if applicable for this host platform) in this process.  */
  60   uint64_t sys;
  61
  62   /* Wall clock time.  */
  63   uint64_t wall;
  64
  65   /* Garbage collector memory.  */
  66   size_t ggc_mem;
  67 };
  68
  69 /* An enumeration of timing variable identifiers.  Constructed from
  70    the contents of timevar.def.  */
  71
  72 #define DEFTIMEVAR(identifier__, name__) \
  73     identifier__,
  74 typedef enum
  75 {
  76   TV_NONE,
  77 #include "timevar.def"
  78   TIMEVAR_LAST
  79 }
  80 timevar_id_t;
  81 #undef DEFTIMEVAR
  82
  83 /* A class to hold all state relating to timing.  */
  84
  85 class timer;
  86
  87 /* The singleton instance of timing state.
  88
  89    This is non-NULL if timevars should be used.  In GCC, this happens with
  90    the -ftime-report flag.  Hence this is NULL for the common,
  91    needs-to-be-fast case, with an early reject happening for this being
  92    NULL.  */
  93 extern timer *g_timer;
  94
  95 /* Total amount of memory allocated by garbage collector.  */
  96 extern size_t timevar_ggc_mem_total;
  97
  98 extern void timevar_init (void);
  99 extern void timevar_start (timevar_id_t);
 100 extern void timevar_stop (timevar_id_t);
 101 extern bool timevar_cond_start (timevar_id_t);
 102 extern void timevar_cond_stop (timevar_id_t, bool);
 103
 104 /* The public (within GCC) interface for timing.  */
 105
 106 class timer
 107 {
 108  public:
 109   timer ();
 110   ~timer ();
 111
 112   void start (timevar_id_t tv);
 113   void stop (timevar_id_t tv);
 114   void push (timevar_id_t tv);
 115   void pop (timevar_id_t tv);
 116   bool cond_start (timevar_id_t tv);
 117   void cond_stop (timevar_id_t tv);
 118
 119   void push_client_item (const char *item_name);
 120   void pop_client_item ();
 121
 122   void print (FILE *fp);
 123   json::value *make_json () const;
 124
 125   const char *get_topmost_item_name () const;
 126
 127  private:
 128   /* Private member functions.  */
 129   void validate_phases (FILE *fp) const;
 130
 131   struct timevar_def;
 132   void push_internal (struct timevar_def *tv);
 133   void pop_internal ();
 134   static void print_row (FILE *fp,
 135                          const timevar_time_def *total,
 136                          const char *name, const timevar_time_def &elapsed);
 137   static bool all_zero (const timevar_time_def &elapsed);
 138
 139  private:
 140   typedef hash_map<timevar_def *, timevar_time_def> child_map_t;
 141
 142   /* Private type: a timing variable.  */
 143   struct timevar_def
 144   {
 145     json::value *make_json () const;
 146
 147     /* Elapsed time for this variable.  */
 148     struct timevar_time_def elapsed;
 149
 150     /* If this variable is timed independently of the timing stack,
 151        using timevar_start, this contains the start time.  */
 152     struct timevar_time_def start_time;
 153
 154     /* The name of this timing variable.  */
 155     const char *name;
 156
 157     /* Nonzero if this timing variable is running as a standalone
 158        timer.  */
 159     unsigned standalone : 1;
 160
 161     /* Nonzero if this timing variable was ever started or pushed onto
 162        the timing stack.  */
 163     unsigned used : 1;
 164
 165     child_map_t *children;
 166   };
 167
 168   /* Private type: an element on the timing stack
 169      Elapsed time is attributed to the topmost timing variable on the
 170      stack.  */
 171   struct timevar_stack_def
 172   {
 173     /* The timing variable at this stack level.  */
 174     struct timevar_def *timevar;
 175
 176     /* The next lower timing variable context in the stack.  */
 177     struct timevar_stack_def *next;
 178   };
 179
 180   /* A class for managing a collection of named timing items, for use
 181      e.g. by libgccjit for timing client code.  This class is declared
 182      inside timevar.cc to avoid everything using timevar.h
 183      from needing vec and hash_map.  */
 184   class named_items;
 185
 186  private:
 187
 188   /* Data members (all private).  */
 189
 190   /* Declared timing variables.  Constructed from the contents of
 191      timevar.def.  */
 192   timevar_def m_timevars[TIMEVAR_LAST];
 193
 194   /* The top of the timing stack.  */
 195   timevar_stack_def *m_stack;
 196
 197   /* A list of unused (i.e. allocated and subsequently popped)
 198      timevar_stack_def instances.  */
 199   timevar_stack_def *m_unused_stack_instances;
 200
 201   /* The time at which the topmost element on the timing stack was
 202      pushed.  Time elapsed since then is attributed to the topmost
 203      element.  */
 204   timevar_time_def m_start_time;
 205
 206   /* If non-NULL, for use when timing libgccjit's client code.  */
 207   named_items *m_jit_client_items;
 208
 209   friend class named_items;
 210 };
 211
 212 /* Provided for backward compatibility.  */
 213 inline void
 214 timevar_push (timevar_id_t tv)
 215 {
 216   if (g_timer)
 217     g_timer->push (tv);
 218 }
 219
 220 inline void
 221 timevar_pop (timevar_id_t tv)
 222 {
 223   if (g_timer)
 224     g_timer->pop (tv);
 225 }
 226
 227 // This is a simple timevar wrapper class that pushes a timevar in its
 228 // constructor and pops the timevar in its destructor.
 229 class auto_timevar
 230 {
 231  public:
 232   auto_timevar (timer *t, timevar_id_t tv)
 233     : m_timer (t),
 234       m_tv (tv)
 235   {
 236     if (m_timer)
 237       m_timer->push (m_tv);
 238   }
 239
 240   explicit auto_timevar (timevar_id_t tv)
 241     : m_timer (g_timer)
 242     , m_tv (tv)
 243   {
 244     if (m_timer)
 245       m_timer->push (m_tv);
 246   }
 247
 248   ~auto_timevar ()
 249   {
 250     if (m_timer)
 251       m_timer->pop (m_tv);
 252   }
 253
 254   // Disallow copies.
 255   auto_timevar (const auto_timevar &) = delete;
 256
 257  private:
 258   timer *m_timer;
 259   timevar_id_t m_tv;
 260 };
 261
 262 // As above, but use cond_start/stop.
 263 class auto_cond_timevar
 264 {
 265  public:
 266   auto_cond_timevar (timer *t, timevar_id_t tv)
 267     : m_timer (t),
 268       m_tv (tv)
 269   {
 270     start ();
 271   }
 272
 273   explicit auto_cond_timevar (timevar_id_t tv)
 274     : m_timer (g_timer)
 275     , m_tv (tv)
 276   {
 277     start ();
 278   }
 279
 280   ~auto_cond_timevar ()
 281   {
 282     if (m_timer && !already_running)
 283       m_timer->cond_stop (m_tv);
 284   }
 285
 286   // Disallow copies.
 287   auto_cond_timevar (const auto_cond_timevar &) = delete;
 288
 289  private:
 290   void start()
 291   {
 292     if (m_timer)
 293       already_running = m_timer->cond_start (m_tv);
 294     else
 295       already_running = false;
 296   }
 297
 298   timer *m_timer;
 299   timevar_id_t m_tv;
 300   bool already_running;
 301 };
 302
 303 extern void print_time (const char *, long);
 304
 305 #endif /* ! GCC_TIMEVAR_H */