sim/common/cgen-run.c

   1 /* Main simulator loop for CGEN-based simulators.
   2    Copyright (C) 1998-2017 Free Software Foundation, Inc.
   3    Contributed by Cygnus Solutions.
   4
   5 This file is part of GDB, the GNU debugger.
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3 of the License, or
  10 (at your option) any later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 /* ??? These are old notes, kept around for now.
  21    Collecting profile data and tracing slow us down so we don't do them in
  22    "fast mode".
  23    There are 6 possibilities on 2 axes:
  24    - no-scaching, insn-scaching, basic-block-scaching
  25    - run with full features or run fast
  26    Supporting all six possibilities in one executable is a bit much but
  27    supporting full/fast seems reasonable.
  28    If the scache is configured in it is always used.
  29    If pbb-scaching is configured in it is always used.
  30    ??? Sometimes supporting more than one set of semantic functions will make
  31    the simulator too large - this should be configurable.  Blah blah blah.
  32    ??? Supporting full/fast can be more modular, blah blah blah.
  33    When the framework is more modular, this can be.
  34 */
  35
  36 #include "sim-main.h"
  37 #include "sim-assert.h"
  38
  39 #ifndef SIM_ENGINE_PREFIX_HOOK
  40 #define SIM_ENGINE_PREFIX_HOOK(sd)
  41 #endif
  42 #ifndef SIM_ENGINE_POSTFIX_HOOK
  43 #define SIM_ENGINE_POSTFIX_HOOK(sd)
  44 #endif
  45
  46 static sim_event_handler has_stepped;
  47 static void prime_cpu (SIM_CPU *, int);
  48 static void engine_run_1 (SIM_DESC, int, int);
  49 static void engine_run_n (SIM_DESC, int, int, int, int);
  50
  51 /* sim_resume for cgen */
  52
  53 void
  54 sim_resume (SIM_DESC sd, int step, int siggnal)
  55 {
  56   sim_engine *engine = STATE_ENGINE (sd);
  57   jmp_buf buf;
  58   int jmpval;
  59
  60   ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);
  61
  62   /* we only want to be single stepping the simulator once */
  63   if (engine->stepper != NULL)
  64     {
  65       sim_events_deschedule (sd, engine->stepper);
  66       engine->stepper = NULL;
  67     }
  68   if (step)
  69     engine->stepper = sim_events_schedule (sd, 1, has_stepped, sd);
  70
  71   sim_module_resume (sd);
  72
  73 #if WITH_SCACHE
  74   if (USING_SCACHE_P (sd))
  75     scache_flush (sd);
  76 #endif
  77
  78   /* run/resume the simulator */
  79
  80   sim_engine_set_run_state (sd, sim_running, 0);
  81
  82   engine->jmpbuf = &buf;
  83   jmpval = setjmp (buf);
  84   if (jmpval == sim_engine_start_jmpval
  85       || jmpval == sim_engine_restart_jmpval)
  86     {
  87       int last_cpu_nr = sim_engine_last_cpu_nr (sd);
  88       int next_cpu_nr = sim_engine_next_cpu_nr (sd);
  89       int nr_cpus = sim_engine_nr_cpus (sd);
  90       /* ??? Setting max_insns to 0 allows pbb/jit code to run wild and is
  91          useful if all one wants to do is run a benchmark.  Need some better
  92          way to identify this case.  */
  93       int max_insns = (step
  94                        ? 1
  95                        : (nr_cpus == 1
  96                           /*&& wip:no-events*/
  97                           /* Don't do this if running under gdb, need to
  98                              poll ui for events.  */
  99                           && STATE_OPEN_KIND (sd) == SIM_OPEN_STANDALONE)
 100                        ? 0
 101                        : 8); /*FIXME: magic number*/
 102       int fast_p = STATE_RUN_FAST_P (sd);
 103
 104       sim_events_preprocess (sd, last_cpu_nr >= nr_cpus, next_cpu_nr >= nr_cpus);
 105       if (next_cpu_nr >= nr_cpus)
 106         next_cpu_nr = 0;
 107       if (nr_cpus == 1)
 108         engine_run_1 (sd, max_insns, fast_p);
 109       else
 110         engine_run_n (sd, next_cpu_nr, nr_cpus, max_insns, fast_p);
 111     }
 112 #if 1 /*wip*/
 113   else
 114     {
 115       /* Account for the last insn executed.  */
 116       SIM_CPU *cpu = STATE_CPU (sd, sim_engine_last_cpu_nr (sd));
 117       ++ CPU_INSN_COUNT (cpu);
 118       CGEN_TRACE_INSN_FINI (cpu, NULL, 1);
 119     }
 120 #endif
 121
 122   engine->jmpbuf = NULL;
 123
 124   {
 125     int i;
 126     int nr_cpus = sim_engine_nr_cpus (sd);
 127
 128 #if 0 /*wip,ignore*/
 129     /* If the loop exits, either we single-stepped or @cpu@_engine_stop
 130        was called.  */
 131     if (step)
 132       sim_engine_set_run_state (sd, sim_stopped, SIM_SIGTRAP);
 133     else
 134       sim_engine_set_run_state (sd, pending_reason, pending_sigrc);
 135 #endif
 136
 137     for (i = 0; i < nr_cpus; ++i)
 138       {
 139         SIM_CPU *cpu = STATE_CPU (sd, i);
 140
 141         PROFILE_TOTAL_INSN_COUNT (CPU_PROFILE_DATA (cpu)) += CPU_INSN_COUNT (cpu);
 142       }
 143   }
 144
 145   sim_module_suspend (sd);
 146 }
 147
 148 /* Halt the simulator after just one instruction.  */
 149
 150 static void
 151 has_stepped (SIM_DESC sd, void *data)
 152 {
 153   ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);
 154   sim_engine_halt (sd, NULL, NULL, NULL_CIA, sim_stopped, SIM_SIGTRAP);
 155 }
 156
 157 /* Prepare a cpu for running.
 158    MAX_INSNS is the number of insns to execute per time slice.
 159    If 0 it means the cpu can run as long as it wants (e.g. until the
 160    program completes).
 161    ??? Perhaps this should be an argument to the engine_fn.  */
 162
 163 static void
 164 prime_cpu (SIM_CPU *cpu, int max_insns)
 165 {
 166   CPU_MAX_SLICE_INSNS (cpu) = max_insns;
 167   CPU_INSN_COUNT (cpu) = 0;
 168
 169   /* Initialize the insn descriptor table.
 170      This has to be done after all initialization so we just defer it to
 171      here.  */
 172
 173   if (MACH_PREPARE_RUN (CPU_MACH (cpu)))
 174     (* MACH_PREPARE_RUN (CPU_MACH (cpu))) (cpu);
 175 }
 176
 177 /* Main loop, for 1 cpu.  */
 178
 179 static void
 180 engine_run_1 (SIM_DESC sd, int max_insns, int fast_p)
 181 {
 182   sim_cpu *cpu = STATE_CPU (sd, 0);
 183   ENGINE_FN *fn = fast_p ? CPU_FAST_ENGINE_FN (cpu) : CPU_FULL_ENGINE_FN (cpu);
 184
 185   prime_cpu (cpu, max_insns);
 186
 187   while (1)
 188     {
 189       SIM_ENGINE_PREFIX_HOOK (sd);
 190
 191       (*fn) (cpu);
 192
 193       SIM_ENGINE_POSTFIX_HOOK (sd);
 194
 195       /* process any events */
 196       if (sim_events_tick (sd))
 197         sim_events_process (sd);
 198     }
 199 }
 200
 201 /* Main loop, for multiple cpus.  */
 202
 203 static void
 204 engine_run_n (SIM_DESC sd, int next_cpu_nr, int nr_cpus, int max_insns, int fast_p)
 205 {
 206   int i;
 207   ENGINE_FN *engine_fns[MAX_NR_PROCESSORS];
 208
 209   for (i = 0; i < nr_cpus; ++i)
 210     {
 211       SIM_CPU *cpu = STATE_CPU (sd, i);
 212
 213       engine_fns[i] = fast_p ? CPU_FAST_ENGINE_FN (cpu) : CPU_FULL_ENGINE_FN (cpu);
 214       prime_cpu (cpu, max_insns);
 215     }
 216
 217   while (1)
 218     {
 219       SIM_ENGINE_PREFIX_HOOK (sd);
 220
 221       /* FIXME: proper cycling of all of them, blah blah blah.  */
 222       while (next_cpu_nr != nr_cpus)
 223         {
 224           SIM_CPU *cpu = STATE_CPU (sd, next_cpu_nr);
 225
 226           (* engine_fns[next_cpu_nr]) (cpu);
 227           ++next_cpu_nr;
 228         }
 229
 230       SIM_ENGINE_POSTFIX_HOOK (sd);
 231
 232       /* process any events */
 233       if (sim_events_tick (sd))
 234         sim_events_process (sd);
 235     }
 236 }