sim/common/cgen-run.c

   1 /* Main simulator loop for CGEN-based simulators.
   2    Copyright (C) 1998-2023 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 /* This must come before any other includes.  */
  37 #include "defs.h"
  38
  39 #include "sim-main.h"
  40 #include "sim-assert.h"
  41 #include "sim-signal.h"
  42
  43 #ifndef SIM_ENGINE_PREFIX_HOOK
  44 #define SIM_ENGINE_PREFIX_HOOK(sd)
  45 #endif
  46 #ifndef SIM_ENGINE_POSTFIX_HOOK
  47 #define SIM_ENGINE_POSTFIX_HOOK(sd)
  48 #endif
  49
  50 static sim_event_handler has_stepped;
  51 static void prime_cpu (SIM_CPU *, int);
  52 static void engine_run_1 (SIM_DESC, int, int);
  53 static void engine_run_n (SIM_DESC, int, int, int, int);
  54
  55 /* If no profiling or tracing has been enabled, run in fast mode.  */
  56 static int
  57 cgen_get_fast_p (SIM_DESC sd)
  58 {
  59   int i, c;
  60   int run_fast_p = 1;
  61
  62   for (c = 0; c < MAX_NR_PROCESSORS; ++c)
  63     {
  64       SIM_CPU *cpu = STATE_CPU (sd, c);
  65
  66       if (PROFILE_ANY_P (cpu) || TRACE_ANY_P (cpu))
  67         return 0;
  68     }
  69
  70   return 1;
  71 }
  72
  73 /* sim_resume for cgen */
  74
  75 void
  76 sim_resume (SIM_DESC sd, int step, int siggnal)
  77 {
  78   sim_engine *engine = STATE_ENGINE (sd);
  79   jmp_buf buf;
  80   int jmpval;
  81   static int fast_p = -1;
  82
  83   ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);
  84
  85   if (fast_p == -1)
  86     fast_p = cgen_get_fast_p (sd);
  87
  88   /* we only want to be single stepping the simulator once */
  89   if (engine->stepper != NULL)
  90     {
  91       sim_events_deschedule (sd, engine->stepper);
  92       engine->stepper = NULL;
  93     }
  94   if (step)
  95     engine->stepper = sim_events_schedule (sd, 1, has_stepped, sd);
  96
  97   sim_module_resume (sd);
  98
  99 #if WITH_SCACHE
 100   if (USING_SCACHE_P (sd))
 101     scache_flush (sd);
 102 #endif
 103
 104   /* run/resume the simulator */
 105
 106   sim_engine_set_run_state (sd, sim_running, 0);
 107
 108   engine->jmpbuf = &buf;
 109   jmpval = setjmp (buf);
 110   if (jmpval == sim_engine_start_jmpval
 111       || jmpval == sim_engine_restart_jmpval)
 112     {
 113       int last_cpu_nr = sim_engine_last_cpu_nr (sd);
 114       int next_cpu_nr = sim_engine_next_cpu_nr (sd);
 115       int nr_cpus = sim_engine_nr_cpus (sd);
 116       /* ??? Setting max_insns to 0 allows pbb/jit code to run wild and is
 117          useful if all one wants to do is run a benchmark.  Need some better
 118          way to identify this case.  */
 119       int max_insns = (step
 120                        ? 1
 121                        : (nr_cpus == 1
 122                           /*&& wip:no-events*/
 123                           /* Don't do this if running under gdb, need to
 124                              poll ui for events.  */
 125                           && STATE_OPEN_KIND (sd) == SIM_OPEN_STANDALONE)
 126                        ? 0
 127                        : 8); /*FIXME: magic number*/
 128
 129       sim_events_preprocess (sd, last_cpu_nr >= nr_cpus, next_cpu_nr >= nr_cpus);
 130       if (next_cpu_nr >= nr_cpus)
 131         next_cpu_nr = 0;
 132       if (nr_cpus == 1)
 133         engine_run_1 (sd, max_insns, fast_p);
 134       else
 135         engine_run_n (sd, next_cpu_nr, nr_cpus, max_insns, fast_p);
 136     }
 137 #if 1 /*wip*/
 138   else
 139     {
 140       /* Account for the last insn executed.  */
 141       SIM_CPU *cpu = STATE_CPU (sd, sim_engine_last_cpu_nr (sd));
 142       ++ CPU_INSN_COUNT (cpu);
 143       CGEN_TRACE_INSN_FINI (cpu, NULL, 1);
 144     }
 145 #endif
 146
 147   engine->jmpbuf = NULL;
 148
 149   {
 150     int i;
 151     int nr_cpus = sim_engine_nr_cpus (sd);
 152
 153 #if 0 /*wip,ignore*/
 154     /* If the loop exits, either we single-stepped or @cpu@_engine_stop
 155        was called.  */
 156     if (step)
 157       sim_engine_set_run_state (sd, sim_stopped, SIM_SIGTRAP);
 158     else
 159       sim_engine_set_run_state (sd, pending_reason, pending_sigrc);
 160 #endif
 161
 162     for (i = 0; i < nr_cpus; ++i)
 163       {
 164         SIM_CPU *cpu = STATE_CPU (sd, i);
 165
 166         PROFILE_TOTAL_INSN_COUNT (CPU_PROFILE_DATA (cpu)) += CPU_INSN_COUNT (cpu);
 167       }
 168   }
 169
 170   sim_module_suspend (sd);
 171 }
 172
 173 /* Halt the simulator after just one instruction.  */
 174
 175 static void
 176 has_stepped (SIM_DESC sd, void *data)
 177 {
 178   ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);
 179   sim_engine_halt (sd, NULL, NULL, NULL_CIA, sim_stopped, SIM_SIGTRAP);
 180 }
 181
 182 /* Prepare a cpu for running.
 183    MAX_INSNS is the number of insns to execute per time slice.
 184    If 0 it means the cpu can run as long as it wants (e.g. until the
 185    program completes).
 186    ??? Perhaps this should be an argument to the engine_fn.  */
 187
 188 static void
 189 prime_cpu (SIM_CPU *cpu, int max_insns)
 190 {
 191   CPU_MAX_SLICE_INSNS (cpu) = max_insns;
 192   CPU_INSN_COUNT (cpu) = 0;
 193
 194   /* Initialize the insn descriptor table.
 195      This has to be done after all initialization so we just defer it to
 196      here.  */
 197
 198   if (MACH_PREPARE_RUN (CPU_MACH (cpu)))
 199     (* MACH_PREPARE_RUN (CPU_MACH (cpu))) (cpu);
 200 }
 201
 202 /* Main loop, for 1 cpu.  */
 203
 204 static void
 205 engine_run_1 (SIM_DESC sd, int max_insns, int fast_p)
 206 {
 207   sim_cpu *cpu = STATE_CPU (sd, 0);
 208   ENGINE_FN *fn = fast_p ? CPU_FAST_ENGINE_FN (cpu) : CPU_FULL_ENGINE_FN (cpu);
 209
 210   prime_cpu (cpu, max_insns);
 211
 212   while (1)
 213     {
 214       SIM_ENGINE_PREFIX_HOOK (sd);
 215
 216       (*fn) (cpu);
 217
 218       SIM_ENGINE_POSTFIX_HOOK (sd);
 219
 220       /* process any events */
 221       if (sim_events_tick (sd))
 222         sim_events_process (sd);
 223     }
 224 }
 225
 226 /* Main loop, for multiple cpus.  */
 227
 228 static void
 229 engine_run_n (SIM_DESC sd, int next_cpu_nr, int nr_cpus, int max_insns, int fast_p)
 230 {
 231   int i;
 232   /* Ensure that engine_fns is fully initialized, this silences a compiler
 233      warning when engine_fns is used below.  */
 234   ENGINE_FN *engine_fns[MAX_NR_PROCESSORS] = {};
 235
 236   SIM_ASSERT (nr_cpus <= MAX_NR_PROCESSORS);
 237   SIM_ASSERT (next_cpu_nr >= 0 && next_cpu_nr < nr_cpus);
 238
 239   for (i = 0; i < nr_cpus; ++i)
 240     {
 241       SIM_CPU *cpu = STATE_CPU (sd, i);
 242
 243       engine_fns[i] = fast_p ? CPU_FAST_ENGINE_FN (cpu) : CPU_FULL_ENGINE_FN (cpu);
 244       prime_cpu (cpu, max_insns);
 245     }
 246
 247   while (1)
 248     {
 249       SIM_ENGINE_PREFIX_HOOK (sd);
 250
 251       /* FIXME: proper cycling of all of them, blah blah blah.  */
 252       while (next_cpu_nr < nr_cpus)
 253         {
 254           SIM_CPU *cpu = STATE_CPU (sd, next_cpu_nr);
 255
 256           (* engine_fns[next_cpu_nr]) (cpu);
 257           ++next_cpu_nr;
 258         }
 259
 260       SIM_ENGINE_POSTFIX_HOOK (sd);
 261
 262       /* process any events */
 263       if (sim_events_tick (sd))
 264         sim_events_process (sd);
 265     }
 266 }