sim/common/cgen-scache.h

/* Simulator header for cgen scache support.
   Copyright (C) 1998-2024 Free Software Foundation, Inc.
   Contributed by Cygnus Solutions.

This file is part of GDB, the GNU debugger.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#ifndef CGEN_SCACHE_H
#define CGEN_SCACHE_H

/* When caching bb's, instructions are extracted into "chains".
   SCACHE_MAP is a hash table into these chains.  */

typedef struct {
  IADDR pc;
  SCACHE *sc;
} SCACHE_MAP;

typedef struct cpu_scache {
  /* Simulator cache size.  Must be a power of 2.
     This is the number of elements in the `cache' member.  */
  unsigned int size;
#define CPU_SCACHE_SIZE(cpu) ((cpu) -> cgen_cpu.scache.size)
  /* The cache.  */
  SCACHE *cache;
#define CPU_SCACHE_CACHE(cpu) ((cpu) -> cgen_cpu.scache.cache)

#if WITH_SCACHE_PBB
  /* Number of hash chains.  Must be a power of 2.  */
  unsigned int num_hash_chains;
#define CPU_SCACHE_NUM_HASH_CHAINS(cpu) ((cpu) -> cgen_cpu.scache.num_hash_chains)
  /* Number of entries in each hash chain.
     The hash table is a statically allocated NxM array where
     N = num_hash_chains
     M = num_hash_chain_entries.  */
  unsigned int num_hash_chain_entries;
#define CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES(cpu) ((cpu) -> cgen_cpu.scache.num_hash_chain_entries)
  /* Maximum number of instructions in a chain.
     ??? This just let's us set a static size of chain_lengths table.
     In a simulation that handles more than just the cpu, this might also be
     used to keep too many instructions from being executed before checking
     for events (or some such).  */
  unsigned int max_chain_length;
#define CPU_SCACHE_MAX_CHAIN_LENGTH(cpu) ((cpu) -> cgen_cpu.scache.max_chain_length)
  /* Special scache entry for (re)starting bb extraction.  */
  SCACHE *pbb_begin;
#define CPU_SCACHE_PBB_BEGIN(cpu) ((cpu) -> cgen_cpu.scache.pbb_begin)
  /* Hash table into cached chains.  */
  SCACHE_MAP *hash_table;
#define CPU_SCACHE_HASH_TABLE(cpu) ((cpu) -> cgen_cpu.scache.hash_table)
  /* Next free entry in cache.  */
  SCACHE *next_free;
#define CPU_SCACHE_NEXT_FREE(cpu) ((cpu) -> cgen_cpu.scache.next_free)

  /* Kind of branch being taken.
     Only used by functional semantics, not switch form.  */
  SEM_BRANCH_TYPE pbb_br_type;
#define CPU_PBB_BR_TYPE(cpu) ((cpu) -> cgen_cpu.scache.pbb_br_type)
  /* Target's branch address.  */
  IADDR pbb_br_npc;
#define CPU_PBB_BR_NPC(cpu) ((cpu) -> cgen_cpu.scache.pbb_br_npc)
#endif /* WITH_SCACHE_PBB */

#if WITH_PROFILE_SCACHE_P
  /* Cache hits, misses.  */
  unsigned long hits, misses;
#define CPU_SCACHE_HITS(cpu) ((cpu) -> cgen_cpu.scache.hits)
#define CPU_SCACHE_MISSES(cpu) ((cpu) -> cgen_cpu.scache.misses)

#if WITH_SCACHE_PBB
  /* Chain length counts.
     Each element is a count of the number of chains created with that
     length.  */
  unsigned long *chain_lengths;
#define CPU_SCACHE_CHAIN_LENGTHS(cpu) ((cpu) -> cgen_cpu.scache.chain_lengths)
  /* Number of times cache was flushed due to its being full.  */
  unsigned long full_flushes;
#define CPU_SCACHE_FULL_FLUSHES(cpu) ((cpu) -> cgen_cpu.scache.full_flushes)
#endif
#endif
} CPU_SCACHE;

/* Hash a PC value.
   This is split into two parts to help with moving as much of the
   computation out of the main loop.  */
#define CPU_SCACHE_HASH_MASK(cpu) (CPU_SCACHE_SIZE (cpu) - 1)
#define SCACHE_HASH_PC(pc, mask) \
((CGEN_MIN_INSN_SIZE == 2 ? ((pc) >> 1) \
  : CGEN_MIN_INSN_SIZE == 4 ? ((pc) >> 2) \
  : (pc)) \
 & (mask))

/* Non-zero if cache is in use.  */
#define USING_SCACHE_P(sd) (STATE_SCACHE_SIZE (sd) > 0)

/* Lookup a PC value in the scache [compilation only].  */
extern SCACHE * scache_lookup (SIM_CPU *, IADDR);
/* Return a pointer to at least N buffers.  */
extern SCACHE *scache_lookup_or_alloc (SIM_CPU *, IADDR, int, SCACHE **);
/* Flush all cpu's scaches.  */
extern void scache_flush (SIM_DESC);
/* Flush a cpu's scache.  */
extern void scache_flush_cpu (SIM_CPU *);

/* Scache profiling support.  */

/* Print summary scache usage information.  */
extern void scache_print_profile (SIM_CPU *cpu, bool verbose);

#if WITH_PROFILE_SCACHE_P

#define PROFILE_COUNT_SCACHE_HIT(cpu) \
do { \
  if (CPU_PROFILE_FLAGS (cpu) [PROFILE_SCACHE_IDX]) \
    ++ CPU_SCACHE_HITS (cpu); \
} while (0)
#define PROFILE_COUNT_SCACHE_MISS(cpu) \
do { \
  if (CPU_PROFILE_FLAGS (cpu) [PROFILE_SCACHE_IDX]) \
    ++ CPU_SCACHE_MISSES (cpu); \
} while (0)
#define PROFILE_COUNT_SCACHE_CHAIN_LENGTH(cpu,length) \
do { \
  if (CPU_PROFILE_FLAGS (cpu) [PROFILE_SCACHE_IDX]) \
    ++ CPU_SCACHE_CHAIN_LENGTHS (cpu) [length]; \
} while (0)
#define PROFILE_COUNT_SCACHE_FULL_FLUSH(cpu) \
do { \
  if (CPU_PROFILE_FLAGS (cpu) [PROFILE_SCACHE_IDX]) \
    ++ CPU_SCACHE_FULL_FLUSHES (cpu); \
} while (0)

#else

#define PROFILE_COUNT_SCACHE_HIT(cpu)
#define PROFILE_COUNT_SCACHE_MISS(cpu)
#define PROFILE_COUNT_SCACHE_CHAIN_LENGTH(cpu,length)
#define PROFILE_COUNT_SCACHE_FULL_FLUSH(cpu)

#endif

#endif /* CGEN_SCACHE_H */