Initial creation of sourceware repositorygdb-4_18-branchpoint

1 files changed, 471 insertions, 0 deletions

diff --git a/sim/common/cgen-scache.c b/sim/common/cgen-scache.c
new file mode 100644
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--- /dev/null
+++ b/sim/common/cgen-scache.c
@@ -0,0 +1,471 @@
+/* Simulator cache routines for CGEN simulators (and maybe others).
+   Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
+   Contributed by Cygnus Support.
+
+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 2, 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, write to the Free Software Foundation, Inc.,
+59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#define SCACHE_DEFINE_INLINE
+
+#include "sim-main.h"
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+#include "libiberty.h"
+#include "sim-options.h"
+#include "sim-io.h"
+
+#define MAX(a,b) ((a) > (b) ? (a) : (b))
+
+/* Unused address.  */
+#define UNUSED_ADDR 0xffffffff
+
+/* Scache configuration parameters.
+   ??? Experiments to determine reasonable values is wip.
+   These are just guesses.  */
+
+/* Default number of scache elements.
+   The size of an element is typically 32-64 bytes, so the size of the
+   default scache will be between 512K and 1M bytes.  */
+#ifdef CONFIG_SIM_CACHE_SIZE
+#define SCACHE_DEFAULT_CACHE_SIZE CONFIG_SIM_CACHE_SIZE
+#else
+#define SCACHE_DEFAULT_CACHE_SIZE 16384
+#endif
+
+/* Minimum cache size.
+   The m32r port assumes a cache size of at least 2 so it can decode both 16
+   bit insns.  When compiling we need an extra for the chain entry.  And this
+   must be a multiple of 2.  Hence 4 is the minimum (though, for those with
+   featuritis or itchy pedantic bits, we could make this conditional on
+   WITH_SCACHE_PBB).  */
+#define MIN_SCACHE_SIZE 4
+
+/* Ratio of size of text section to size of scache.
+   When compiling, we don't want to flush the scache more than we have to
+   but we also don't want it to be exorbitantly(sp?) large.  So we pick a high
+   default value, then reduce it by the size of the program being simulated,
+   but we don't override any value specified on the command line.
+   If not specified on the command line, the size to use is computed as
+   max (MIN_SCACHE_SIZE,
+        min (DEFAULT_SCACHE_SIZE,
+             text_size / (base_insn_size * INSN_SCACHE_RATIO))).  */
+/* ??? Interesting idea but not currently used.  */
+#define INSN_SCACHE_RATIO 4
+
+/* Default maximum insn chain length.
+   The only reason for a maximum is so we can place a maximum size on the
+   profiling table.  Chain lengths are determined by cti's.
+   32 is a more reasonable number, but when profiling, the before/after
+   handlers take up that much more space.  The scache is filled from front to
+   back so all this determines is when the scache needs to be flushed.  */
+#define MAX_CHAIN_LENGTH 64
+
+/* Default maximum hash list length.  */
+#define MAX_HASH_CHAIN_LENGTH 4
+
+/* Minimum hash table size.  */
+#define MIN_HASH_CHAINS 32
+
+/* Ratio of number of scache elements to number of hash lists.
+   Since the user can only specify the size of the scache, we compute the
+   size of the hash table as
+   max (MIN_HASH_CHAINS, scache_size / SCACHE_HASH_RATIO).  */
+#define SCACHE_HASH_RATIO 8
+
+/* Hash a PC value.
+   FIXME: May wish to make the hashing architecture specific.
+   FIXME: revisit */
+#define HASH_PC(pc) (((pc) >> 2) + ((pc) >> 5))
+
+static MODULE_INIT_FN scache_init;
+static MODULE_UNINSTALL_FN scache_uninstall;
+
+static DECLARE_OPTION_HANDLER (scache_option_handler);
+
+#define OPTION_PROFILE_SCACHE	(OPTION_START + 0)
+
+static const OPTION scache_options[] = {
+  { {"scache-size", optional_argument, NULL, 'c'},
+      'c', "[SIZE]", "Specify size of simulator execution cache",
+      scache_option_handler },
+#if WITH_SCACHE_PBB
+  /* ??? It might be nice to allow the user to specify the size of the hash
+     table, the maximum hash list length, and the maximum chain length, but
+     for now that might be more akin to featuritis.  */
+#endif
+  { {"profile-scache", optional_argument, NULL, OPTION_PROFILE_SCACHE},
+      '\0', "on|off", "Perform simulator execution cache profiling",
+      scache_option_handler },
+  { {NULL, no_argument, NULL, 0}, '\0', NULL, NULL, NULL }
+};
+
+static SIM_RC
+scache_option_handler (SIM_DESC sd, sim_cpu *cpu, int opt,
+		       char *arg, int is_command)
+{
+  int n;
+
+  switch (opt)
+    {
+    case 'c' :
+      if (WITH_SCACHE)
+	{
+	  if (arg != NULL)
+	    {
+	      int n = strtol (arg, NULL, 0);
+	      if (n < MIN_SCACHE_SIZE)
+		{
+		  sim_io_eprintf (sd, "invalid scache size `%d', must be at least 4", n);
+		  return SIM_RC_FAIL;
+		}
+	      /* Ensure it's a multiple of 2.  */
+	      if ((n & (n - 1)) != 0)
+		{
+		  sim_io_eprintf (sd, "scache size `%d' not a multiple of 2\n", n);
+		  {
+		    /* round up to nearest multiple of 2 */
+		    int i;
+		    for (i = 1; i < n; i <<= 1)
+		      continue;
+		    n = i;
+		  }
+		  sim_io_eprintf (sd, "rounding scache size up to %d\n", n);
+		}
+	      if (cpu == NULL)
+		STATE_SCACHE_SIZE (sd) = n;
+	      else
+		CPU_SCACHE_SIZE (cpu) = n;
+	    }
+	  else
+	    {
+	      if (cpu == NULL)
+		STATE_SCACHE_SIZE (sd) = SCACHE_DEFAULT_CACHE_SIZE;
+	      else
+		CPU_SCACHE_SIZE (cpu) = SCACHE_DEFAULT_CACHE_SIZE;
+	    }
+	}
+      else
+	sim_io_eprintf (sd, "Simulator execution cache not enabled, `--scache-size' ignored\n");
+      break;
+
+    case OPTION_PROFILE_SCACHE :
+      if (WITH_SCACHE && WITH_PROFILE_SCACHE_P)
+	{
+	  /* FIXME: handle cpu != NULL.  */
+	  return sim_profile_set_option (sd, "-scache", PROFILE_SCACHE_IDX,
+					 arg);
+	}
+      else
+	sim_io_eprintf (sd, "Simulator cache profiling not compiled in, `--profile-scache' ignored\n");
+      break;
+    }
+
+  return SIM_RC_OK;
+}
+
+SIM_RC
+scache_install (SIM_DESC sd)
+{
+  sim_add_option_table (sd, NULL, scache_options);
+  sim_module_add_init_fn (sd, scache_init);
+  sim_module_add_uninstall_fn (sd, scache_uninstall);
+
+  /* This is the default, it may be overridden on the command line.  */
+  STATE_SCACHE_SIZE (sd) = WITH_SCACHE;
+
+  return SIM_RC_OK;
+}
+
+static SIM_RC
+scache_init (SIM_DESC sd)
+{
+  int c;
+
+  for (c = 0; c < MAX_NR_PROCESSORS; ++c)
+    {
+      SIM_CPU *cpu = STATE_CPU (sd, c);
+      int elm_size = IMP_PROPS_SCACHE_ELM_SIZE (MACH_IMP_PROPS (CPU_MACH (cpu)));
+
+      /* elm_size is 0 if the cpu doesn't not have scache support */
+      if (elm_size == 0)
+	{
+	  CPU_SCACHE_SIZE (cpu) = 0;
+	  CPU_SCACHE_CACHE (cpu) = NULL;
+	}
+      else
+	{
+	  if (CPU_SCACHE_SIZE (cpu) == 0)
+	    CPU_SCACHE_SIZE (cpu) = STATE_SCACHE_SIZE (sd);
+	  CPU_SCACHE_CACHE (cpu) =
+	    (SCACHE *) xmalloc (CPU_SCACHE_SIZE (cpu) * elm_size);
+#if WITH_SCACHE_PBB
+	  CPU_SCACHE_MAX_CHAIN_LENGTH (cpu) = MAX_CHAIN_LENGTH;
+	  CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu) = MAX_HASH_CHAIN_LENGTH;
+	  CPU_SCACHE_NUM_HASH_CHAINS (cpu) = MAX (MIN_HASH_CHAINS,
+						  CPU_SCACHE_SIZE (cpu)
+						  / SCACHE_HASH_RATIO);
+	  CPU_SCACHE_HASH_TABLE (cpu) =
+	    (SCACHE_MAP *) xmalloc (CPU_SCACHE_NUM_HASH_CHAINS (cpu)
+				    * CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu)
+				    * sizeof (SCACHE_MAP));
+	  CPU_SCACHE_PBB_BEGIN (cpu) = (SCACHE *) zalloc (elm_size);
+	  CPU_SCACHE_CHAIN_LENGTHS (cpu) =
+	    (unsigned long *) zalloc ((CPU_SCACHE_MAX_CHAIN_LENGTH (cpu) + 1)
+				      * sizeof (long));
+#endif
+	}
+    }
+
+  scache_flush (sd);
+
+  return SIM_RC_OK;
+}
+
+static void
+scache_uninstall (SIM_DESC sd)
+{
+  int c;
+
+  for (c = 0; c < MAX_NR_PROCESSORS; ++c)
+    {
+      SIM_CPU *cpu = STATE_CPU (sd, c);
+
+      if (CPU_SCACHE_CACHE (cpu) != NULL)
+	free (CPU_SCACHE_CACHE (cpu));
+#if WITH_SCACHE_PBB
+      if (CPU_SCACHE_HASH_TABLE (cpu) != NULL)
+	free (CPU_SCACHE_HASH_TABLE (cpu));
+      if (CPU_SCACHE_PBB_BEGIN (cpu) != NULL)
+	free (CPU_SCACHE_PBB_BEGIN (cpu));
+      if (CPU_SCACHE_CHAIN_LENGTHS (cpu) != NULL)
+	free (CPU_SCACHE_CHAIN_LENGTHS (cpu));
+#endif
+    }
+}
+
+void
+scache_flush (SIM_DESC sd)
+{
+  int c;
+
+  for (c = 0; c < MAX_NR_PROCESSORS; ++c)
+    {
+      SIM_CPU *cpu = STATE_CPU (sd, c);
+      scache_flush_cpu (cpu);
+    }
+}
+
+void
+scache_flush_cpu (SIM_CPU *cpu)
+{
+  int i,n;
+
+  /* Don't bother if cache not in use.  */
+  if (CPU_SCACHE_SIZE (cpu) == 0)
+    return;
+
+#if WITH_SCACHE_PBB
+  /* It's important that this be reasonably fast as this can be done when
+     the simulation is running.  */
+  CPU_SCACHE_NEXT_FREE (cpu) = CPU_SCACHE_CACHE (cpu);
+  n = CPU_SCACHE_NUM_HASH_CHAINS (cpu) * CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu);
+  /* ??? Might be faster to just set the first entry, then update the
+     "last entry" marker during allocation.  */
+  for (i = 0; i < n; ++i)
+    CPU_SCACHE_HASH_TABLE (cpu) [i] . pc = UNUSED_ADDR;
+#else
+  {
+    int elm_size = IMP_PROPS_SCACHE_ELM_SIZE (MACH_IMP_PROPS (CPU_MACH (cpu)));
+    SCACHE *sc;
+
+    /* Technically, this may not be necessary, but it helps debugging.  */
+    memset (CPU_SCACHE_CACHE (cpu), 0,
+	    CPU_SCACHE_SIZE (cpu) * elm_size);
+
+    for (i = 0, sc = CPU_SCACHE_CACHE (cpu); i < CPU_SCACHE_SIZE (cpu);
+	 ++i, sc = (SCACHE *) ((char *) sc + elm_size))
+      {
+	sc->argbuf.addr = UNUSED_ADDR;
+      }
+  }
+#endif
+}
+
+#if WITH_SCACHE_PBB
+
+/* Look up PC in the hash table of scache entry points.
+   Returns the entry or NULL if not found.  */
+
+SCACHE *
+scache_lookup (SIM_CPU *cpu, IADDR pc)
+{
+  unsigned int slot = HASH_PC (pc) & (CPU_SCACHE_NUM_HASH_CHAINS (cpu) - 1);
+  int i, max_i = CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu);
+  SCACHE_MAP *scm;
+
+  /* We don't update hit/miss statistics as this is only used when recording
+     branch target addresses.  */
+
+  scm = & CPU_SCACHE_HASH_TABLE (cpu) [slot];
+  for (i = 0; i < max_i && scm->pc != UNUSED_ADDR; ++i, ++scm)
+    {
+      if (scm->pc == pc)
+	return scm->sc;
+    }
+  return 0;
+}
+
+/* Look up PC and if not found create an entry for it.
+   If found the result is a pointer to the SCACHE entry.
+   If not found the result is NULL, and the address of a buffer of at least
+   N entries is stored in BUFP.
+   It's done this way so the caller can still distinguish found/not-found.
+   If the table is full, it is emptied to make room.
+   If the maximum length of a hash list is reached a random entry is thrown out
+   to make room.
+   ??? One might want to try to make this smarter, but let's see some
+   measurable benefit first.  */
+
+SCACHE *
+scache_lookup_or_alloc (SIM_CPU *cpu, IADDR pc, int n, SCACHE **bufp)
+{
+  unsigned int slot = HASH_PC (pc) & (CPU_SCACHE_NUM_HASH_CHAINS (cpu) - 1);
+  int i, max_i = CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu);
+  SCACHE_MAP *scm;
+  SCACHE *sc;
+
+  scm = & CPU_SCACHE_HASH_TABLE (cpu) [slot];
+  for (i = 0; i < max_i && scm->pc != UNUSED_ADDR; ++i, ++scm)
+    {
+      if (scm->pc == pc)
+	{
+	  PROFILE_COUNT_SCACHE_HIT (cpu);
+	  return scm->sc;
+	}
+    }
+  PROFILE_COUNT_SCACHE_MISS (cpu);
+
+  /* The address we want isn't cached.  Bummer.
+     If the hash chain we have for this address is full, throw out an entry
+     to make room.  */
+
+  if (i == max_i)
+    {
+      /* Rather than do something sophisticated like LRU, we just throw out
+	 a semi-random entry.  Let someone else have the joy of saying how
+	 wrong this is.  NEXT_FREE is the entry to throw out and cycles
+	 through all possibilities.  */
+      static int next_free = 0;
+
+      scm = & CPU_SCACHE_HASH_TABLE (cpu) [slot];
+      for (i = 0; i < next_free; ++i, ++scm)
+	continue;
+      ++next_free;
+      if (next_free == CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu))
+	next_free = 0;
+    }
+
+  /* At this point SCM points to the hash table entry to use.
+     Now make sure there's room in the cache.  */
+
+  {
+    int elm_size = IMP_PROPS_SCACHE_ELM_SIZE (MACH_IMP_PROPS (CPU_MACH (cpu)));
+    int elms_used = (((char *) CPU_SCACHE_NEXT_FREE (cpu)
+		      - (char *) CPU_SCACHE_CACHE (cpu))
+		     / elm_size);
+    int elms_left = CPU_SCACHE_SIZE (cpu) - elms_used;
+
+    if (elms_left < n)
+      {
+	PROFILE_COUNT_SCACHE_FULL_FLUSH (cpu);
+	scache_flush_cpu (cpu);
+      }
+  }
+
+  sc = CPU_SCACHE_NEXT_FREE (cpu);
+  scm->pc = pc;
+  scm->sc = sc;
+
+  *bufp = sc;
+  return NULL;
+}
+
+#endif /* WITH_SCACHE_PBB */
+
+/* Print cache access statics for CPU.  */
+
+void
+scache_print_profile (SIM_CPU *cpu, int verbose)
+{
+  SIM_DESC sd = CPU_STATE (cpu);
+  unsigned long hits = CPU_SCACHE_HITS (cpu);
+  unsigned long misses = CPU_SCACHE_MISSES (cpu);
+  char buf[20];
+  unsigned long max_val;
+  unsigned long *lengths;
+  int i;
+
+  if (CPU_SCACHE_SIZE (cpu) == 0)
+    return;
+
+  sim_io_printf (sd, "Simulator Cache Statistics\n\n");
+
+  /* One could use PROFILE_LABEL_WIDTH here.  I chose not to.  */
+  sim_io_printf (sd, "  Cache size: %s\n",
+		 sim_add_commas (buf, sizeof (buf), CPU_SCACHE_SIZE (cpu)));
+  sim_io_printf (sd, "  Hits:       %s\n",
+		 sim_add_commas (buf, sizeof (buf), hits));
+  sim_io_printf (sd, "  Misses:     %s\n",
+		 sim_add_commas (buf, sizeof (buf), misses));
+  if (hits + misses != 0)
+    sim_io_printf (sd, "  Hit rate:   %.2f%%\n",
+		   ((double) hits / ((double) hits + (double) misses)) * 100);
+
+#if WITH_SCACHE_PBB
+  sim_io_printf (sd, "\n");
+  sim_io_printf (sd, "  Hash table size:       %s\n",
+		 sim_add_commas (buf, sizeof (buf), CPU_SCACHE_NUM_HASH_CHAINS (cpu)));
+  sim_io_printf (sd, "  Max hash list length:  %s\n",
+		 sim_add_commas (buf, sizeof (buf), CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu)));
+  sim_io_printf (sd, "  Max insn chain length: %s\n",
+		 sim_add_commas (buf, sizeof (buf), CPU_SCACHE_MAX_CHAIN_LENGTH (cpu)));
+  sim_io_printf (sd, "  Cache full flushes:    %s\n",
+		 sim_add_commas (buf, sizeof (buf), CPU_SCACHE_FULL_FLUSHES (cpu)));
+  sim_io_printf (sd, "\n");
+
+  if (verbose)
+    {
+      sim_io_printf (sd, "  Insn chain lengths:\n\n");
+      max_val = 0;
+      lengths = CPU_SCACHE_CHAIN_LENGTHS (cpu);
+      for (i = 1; i < CPU_SCACHE_MAX_CHAIN_LENGTH (cpu); ++i)
+	if (lengths[i] > max_val)
+	  max_val = lengths[i];
+      for (i = 1; i < CPU_SCACHE_MAX_CHAIN_LENGTH (cpu); ++i)
+	{
+	  sim_io_printf (sd, "  %2d: %*s: ",
+			 i,
+			 max_val < 10000 ? 5 : 10,
+			 sim_add_commas (buf, sizeof (buf), lengths[i]));
+	  sim_profile_print_bar (sd, PROFILE_HISTOGRAM_WIDTH,
+				 lengths[i], max_val);
+	  sim_io_printf (sd, "\n");
+	}
+      sim_io_printf (sd, "\n");
+    }
+#endif /* WITH_SCACHE_PBB */
+}