sim/common/cgen-run.c

   1 /* Main simulator loop for CGEN-based simulators.
   2    Copyright (C) 1998-2024 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 c;
  60
  61   for (c = 0; c < MAX_NR_PROCESSORS; ++c)
  62     {
  63       SIM_CPU *cpu = STATE_CPU (sd, c);
  64
  65       if (PROFILE_ANY_P (cpu) || TRACE_ANY_P (cpu))
  66         return 0;
  67     }
  68
  69   return 1;
  70 }
  71
  72 /* sim_resume for cgen */
  73
  74 void
  75 sim_resume (SIM_DESC sd, int step, int siggnal)
  76 {
  77   sim_engine *engine = STATE_ENGINE (sd);
  78   jmp_buf buf;
  79   int jmpval;
  80   static int fast_p = -1;
  81
  82   ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);
  83
  84   if (fast_p == -1)
  85     fast_p = cgen_get_fast_p (sd);
  86
  87   /* we only want to be single stepping the simulator once */
  88   if (engine->stepper != NULL)
  89     {
  90       sim_events_deschedule (sd, engine->stepper);
  91       engine->stepper = NULL;
  92     }
  93   if (step)
  94     engine->stepper = sim_events_schedule (sd, 1, has_stepped, sd);
  95
  96   sim_module_resume (sd);
  97
  98 #if WITH_SCACHE
  99   if (USING_SCACHE_P (sd))
 100     scache_flush (sd);
 101 #endif
 102
 103   /* run/resume the simulator */
 104
 105   sim_engine_set_run_state (sd, sim_running, 0);
 106
 107   engine->jmpbuf = &buf;
 108   jmpval = setjmp (buf);
 109   if (jmpval == sim_engine_start_jmpval
 110       || jmpval == sim_engine_restart_jmpval)
 111     {
 112       int last_cpu_nr = sim_engine_last_cpu_nr (sd);
 113       int next_cpu_nr = sim_engine_next_cpu_nr (sd);
 114       int nr_cpus = sim_engine_nr_cpus (sd);
 115       /* ??? Setting max_insns to 0 allows pbb/jit code to run wild and is
 116          useful if all one wants to do is run a benchmark.  Need some better
 117          way to identify this case.  */
 118       int max_insns = (step
 119                        ? 1
 120                        : (nr_cpus == 1
 121                           /*&& wip:no-events*/
 122                           /* Don't do this if running under gdb, need to
 123                              poll ui for events.  */
 124                           && STATE_OPEN_KIND (sd) == SIM_OPEN_STANDALONE)
 125                        ? 0
 126                        : 8); /*FIXME: magic number*/
 127
 128       sim_events_preprocess (sd, last_cpu_nr >= nr_cpus, next_cpu_nr >= nr_cpus);
 129       if (next_cpu_nr >= nr_cpus)
 130         next_cpu_nr = 0;
 131       if (nr_cpus == 1)
 132         engine_run_1 (sd, max_insns, fast_p);
 133       else
 134         engine_run_n (sd, next_cpu_nr, nr_cpus, max_insns, fast_p);
 135     }
 136 #if 1 /*wip*/
 137   else
 138     {
 139       /* Account for the last insn executed.  */
 140       SIM_CPU *cpu = STATE_CPU (sd, sim_engine_last_cpu_nr (sd));
 141       ++ CPU_INSN_COUNT (cpu);
 142       CGEN_TRACE_INSN_FINI (cpu, NULL, 1);
 143     }
 144 #endif
 145
 146   engine->jmpbuf = NULL;
 147
 148   {
 149     int i;
 150     int nr_cpus = sim_engine_nr_cpus (sd);
 151
 152 #if 0 /*wip,ignore*/
 153     /* If the loop exits, either we single-stepped or @cpu@_engine_stop
 154        was called.  */
 155     if (step)
 156       sim_engine_set_run_state (sd, sim_stopped, SIM_SIGTRAP);
 157     else
 158       sim_engine_set_run_state (sd, pending_reason, pending_sigrc);
 159 #endif
 160
 161     for (i = 0; i < nr_cpus; ++i)
 162       {
 163         SIM_CPU *cpu = STATE_CPU (sd, i);
 164
 165         PROFILE_TOTAL_INSN_COUNT (CPU_PROFILE_DATA (cpu)) += CPU_INSN_COUNT (cpu);
 166       }
 167   }
 168
 169   sim_module_suspend (sd);
 170 }
 171
 172 /* Halt the simulator after just one instruction.  */
 173
 174 static void
 175 has_stepped (SIM_DESC sd, void *data)
 176 {
 177   ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);
 178   sim_engine_halt (sd, NULL, NULL, NULL_CIA, sim_stopped, SIM_SIGTRAP);
 179 }
 180
 181 /* Prepare a cpu for running.
 182    MAX_INSNS is the number of insns to execute per time slice.
 183    If 0 it means the cpu can run as long as it wants (e.g. until the
 184    program completes).
 185    ??? Perhaps this should be an argument to the engine_fn.  */
 186
 187 static void
 188 prime_cpu (SIM_CPU *cpu, int max_insns)
 189 {
 190   CPU_MAX_SLICE_INSNS (cpu) = max_insns;
 191   CPU_INSN_COUNT (cpu) = 0;
 192
 193   /* Initialize the insn descriptor table.
 194      This has to be done after all initialization so we just defer it to
 195      here.  */
 196
 197   if (MACH_PREPARE_RUN (CPU_MACH (cpu)))
 198     (* MACH_PREPARE_RUN (CPU_MACH (cpu))) (cpu);
 199 }
 200
 201 /* Main loop, for 1 cpu.  */
 202
 203 static void
 204 engine_run_1 (SIM_DESC sd, int max_insns, int fast_p)
 205 {
 206   sim_cpu *cpu = STATE_CPU (sd, 0);
 207   ENGINE_FN *fn = fast_p ? CPU_FAST_ENGINE_FN (cpu) : CPU_FULL_ENGINE_FN (cpu);
 208
 209   prime_cpu (cpu, max_insns);
 210
 211   while (1)
 212     {
 213       SIM_ENGINE_PREFIX_HOOK (sd);
 214
 215       (*fn) (cpu);
 216
 217       SIM_ENGINE_POSTFIX_HOOK (sd);
 218
 219       /* process any events */
 220       if (sim_events_tick (sd))
 221         sim_events_process (sd);
 222     }
 223 }
 224
 225 /* Main loop, for multiple cpus.  */
 226
 227 static void
 228 engine_run_n (SIM_DESC sd, int next_cpu_nr, int nr_cpus, int max_insns, int fast_p)
 229 {
 230   int i;
 231   /* Ensure that engine_fns is fully initialized, this silences a compiler
 232      warning when engine_fns is used below.  */
 233   ENGINE_FN *engine_fns[MAX_NR_PROCESSORS] = {};
 234
 235   SIM_ASSERT (nr_cpus <= MAX_NR_PROCESSORS);
 236   SIM_ASSERT (next_cpu_nr >= 0 && next_cpu_nr < nr_cpus);
 237
 238   for (i = 0; i < nr_cpus; ++i)
 239     {
 240       SIM_CPU *cpu = STATE_CPU (sd, i);
 241
 242       engine_fns[i] = fast_p ? CPU_FAST_ENGINE_FN (cpu) : CPU_FULL_ENGINE_FN (cpu);
 243       prime_cpu (cpu, max_insns);
 244     }
 245
 246   while (1)
 247     {
 248       SIM_ENGINE_PREFIX_HOOK (sd);
 249
 250       /* FIXME: proper cycling of all of them, blah blah blah.  */
 251       while (next_cpu_nr < nr_cpus)
 252         {
 253           SIM_CPU *cpu = STATE_CPU (sd, next_cpu_nr);
 254
 255           (* engine_fns[next_cpu_nr]) (cpu);
 256           ++next_cpu_nr;
 257         }
 258
 259       SIM_ENGINE_POSTFIX_HOOK (sd);
 260
 261       /* process any events */
 262       if (sim_events_tick (sd))
 263         sim_events_process (sd);
 264     }
 265 }