xtensa: add --auto-litpools option
authorMax Filippov <jcmvbkbc@gmail.com>
Wed, 29 Jul 2015 14:42:54 +0000 (17:42 +0300)
committerMax Filippov <jcmvbkbc@gmail.com>
Wed, 12 Aug 2015 17:19:58 +0000 (20:19 +0300)
Auto-litpools is the automated version of text-section-literals: literal
pool candidate frags are planted every N frags and during relaxation
they are turned into actual literal pools where literals are moved to
become reachable for their first reference by L32R instruction.

2015-08-12  David Weatherford  <weath@cadence.com>
gas/
* config/tc-xtensa.c (struct litpool_frag, struct litpool_seg):
New structures.
(xtensa_maybe_create_literal_pool_frag): New function.
(litpool_seg_list, auto_litpools, auto_litpool_limit)
(litpool_buf, litpool_slotbuf): New static variables.
(option_auto_litpools, option_no_auto_litpools)
(option_auto_litpool_limit): New enum identifiers.
(md_longopts): Add entries for auto-litpools, no-auto-litpools
and auto-litpool-limit.
(md_parse_option): Handle option_auto_litpools,
option_no_auto_litpools and option_auto_litpool_limit.
(md_show_usage): Add help for --[no-]auto-litpools and
--auto-litpool-limit.
(xtensa_mark_literal_pool_location): Record a place for literal
pool with a call to xtensa_maybe_create_literal_pool_frag.
(get_literal_pool_location): Find highest priority literal pool
or convert candidate to literal pool when auto-litpools are used.
(xg_assemble_vliw_tokens): Create literal pool after jump
instruction.
(xtensa_check_frag_count): Create candidate literal pool every
auto_litpool_limit frags.
(xtensa_relax_frag): Add jump around literals to non-empty
literal pool.
(xtensa_move_literals): Estimate literal pool addresses and move
unreachable literals closer to their users, converting candidate
to literal pool if needed.
(xtensa_switch_to_non_abs_literal_fragment): Only emit error
about missing .literal_position in case auto-litpools are not
used.
* config/tc-xtensa.h (xtensa_relax_statesE): New relaxation
state: RELAX_LITERAL_POOL_CANDIDATE_BEGIN.
* doc/as.texinfo (Xtensa options):  Document --auto-litpools and
--no-auto-litpools options.
* doc/c-xtensa.texi (Xtensa options): Likewise.

2015-08-12  Max Filippov  <jcmvbkbc@gmail.com>
gas/testsuite/
* gas/xtensa/all.exp: Add auto-litpools to the list of xtensa
tests.
* gas/xtensa/auto-litpools.s: New file: auto-litpools test.
* gas/xtensa/auto-litpools.s: New file: auto-litpools test
result pattern.

gas/ChangeLog
gas/config/tc-xtensa.c
gas/config/tc-xtensa.h
gas/doc/as.texinfo
gas/doc/c-xtensa.texi
gas/testsuite/ChangeLog
gas/testsuite/gas/xtensa/all.exp
gas/testsuite/gas/xtensa/auto-litpools.d [new file with mode: 0644]
gas/testsuite/gas/xtensa/auto-litpools.s [new file with mode: 0644]

index aea5508bddc51cd44374bb574acc351632dec657..220047c9d6ef4dbbff364ea7524aacb27156ad42 100644 (file)
@@ -1,3 +1,40 @@
+2015-08-12  David Weatherford  <weath@cadence.com>
+
+       * config/tc-xtensa.c (struct litpool_frag, struct litpool_seg):
+       New structures.
+       (xtensa_maybe_create_literal_pool_frag): New function.
+       (litpool_seg_list, auto_litpools, auto_litpool_limit)
+       (litpool_buf, litpool_slotbuf): New static variables.
+       (option_auto_litpools, option_no_auto_litpools)
+       (option_auto_litpool_limit): New enum identifiers.
+       (md_longopts): Add entries for auto-litpools, no-auto-litpools
+       and auto-litpool-limit.
+       (md_parse_option): Handle option_auto_litpools,
+       option_no_auto_litpools and option_auto_litpool_limit.
+       (md_show_usage): Add help for --[no-]auto-litpools and
+       --auto-litpool-limit.
+       (xtensa_mark_literal_pool_location): Record a place for literal
+       pool with a call to xtensa_maybe_create_literal_pool_frag.
+       (get_literal_pool_location): Find highest priority literal pool
+       or convert candidate to literal pool when auto-litpools are used.
+       (xg_assemble_vliw_tokens): Create literal pool after jump
+       instruction.
+       (xtensa_check_frag_count): Create candidate literal pool every
+       auto_litpool_limit frags.
+       (xtensa_relax_frag): Add jump around literals to non-empty
+       literal pool.
+       (xtensa_move_literals): Estimate literal pool addresses and move
+       unreachable literals closer to their users, converting candidate
+       to literal pool if needed.
+       (xtensa_switch_to_non_abs_literal_fragment): Only emit error
+       about missing .literal_position in case auto-litpools are not
+       used.
+       * config/tc-xtensa.h (xtensa_relax_statesE): New relaxation
+       state: RELAX_LITERAL_POOL_CANDIDATE_BEGIN.
+       * doc/as.texinfo (Xtensa options):  Document --auto-litpools and
+       --no-auto-litpools options.
+       * doc/c-xtensa.texi (Xtensa options): Likewise.
+
 2015-08-12  Simon Dardis  <simon.dardis@imgtec.com>
 
        * config/tc-mips.c (move_register): Change to use 'or' only.
index 7311a054d37118da2056018cda30a1f83e3cfa5c..b8b1e7d6bfe2d33f2914fbfe17f4bbc2b9a652d2 100644 (file)
@@ -440,6 +440,29 @@ bfd_boolean directive_state[] =
 #endif
 };
 
+/* A circular list of all potential and actual literal pool locations
+   in a segment.  */
+struct litpool_frag
+{
+  struct litpool_frag *next;
+  struct litpool_frag *prev;
+  fragS *fragP;
+  addressT addr;
+  short priority; /* 1, 2, or 3 -- 1 is highest  */
+  short original_priority;
+};
+
+/* Map a segment to its litpool_frag list.  */
+struct litpool_seg
+{
+  struct litpool_seg *next;
+  asection *seg;
+  struct litpool_frag frag_list;
+  int frag_count; /* since last litpool location  */
+};
+
+static struct litpool_seg litpool_seg_list;
+
 
 /* Directive functions.  */
 
@@ -474,6 +497,9 @@ static void xtensa_create_trampoline_frag (bfd_boolean);
 static void xtensa_maybe_create_trampoline_frag (void);
 struct trampoline_frag;
 static int init_trampoline_frag (struct trampoline_frag *);
+static void xtensa_maybe_create_literal_pool_frag (bfd_boolean, bfd_boolean);
+static bfd_boolean auto_litpools = FALSE;
+static int auto_litpool_limit = 10000;
 
 /* Alignment Functions.  */
 
@@ -698,6 +724,10 @@ enum
 
   option_trampolines,
   option_no_trampolines,
+
+  option_auto_litpools,
+  option_no_auto_litpools,
+  option_auto_litpool_limit,
 };
 
 const char *md_shortopts = "";
@@ -773,6 +803,10 @@ struct option md_longopts[] =
   { "trampolines", no_argument, NULL, option_trampolines },
   { "no-trampolines", no_argument, NULL, option_no_trampolines },
 
+  { "auto-litpools", no_argument, NULL, option_auto_litpools },
+  { "no-auto-litpools", no_argument, NULL, option_no_auto_litpools },
+  { "auto-litpool-limit", required_argument, NULL, option_auto_litpool_limit },
+
   { NULL, no_argument, NULL, 0 }
 };
 
@@ -961,6 +995,34 @@ md_parse_option (int c, char *arg)
       use_trampolines = FALSE;
       return 1;
 
+    case option_auto_litpools:
+      auto_litpools = TRUE;
+      use_literal_section = FALSE;
+      return 1;
+
+    case option_no_auto_litpools:
+      auto_litpools = FALSE;
+      auto_litpool_limit = -1;
+      return 1;
+
+    case option_auto_litpool_limit:
+      {
+       int value = 0;
+       if (auto_litpool_limit < 0)
+         as_fatal (_("no-auto-litpools is incompatible with auto-litpool-limit"));
+       if (*arg == 0 || *arg == '-')
+         as_fatal (_("invalid auto-litpool-limit argument"));
+       value = strtol (arg, &arg, 10);
+       if (*arg != 0)
+         as_fatal (_("invalid auto-litpool-limit argument"));
+       if (value < 100 || value > 10000)
+         as_fatal (_("invalid auto-litpool-limit argument (range is 100-10000)"));
+       auto_litpool_limit = value;
+       auto_litpools = TRUE;
+       use_literal_section = FALSE;
+       return 1;
+      }
+
     default:
       return 0;
     }
@@ -986,7 +1048,12 @@ Xtensa options:\n\
                           flix bundles\n\
   --rename-section old=new Rename section 'old' to 'new'\n\
   --[no-]trampolines      [Do not] generate trampolines (jumps to jumps)\n\
-                          when jumps do not reach their targets\n", stream);
+                          when jumps do not reach their targets\n\
+  --[no-]auto-litpools    [Do not] automatically create literal pools\n\
+  --auto-litpool-limit=<value>\n\
+                          (range 100-10000) Maximum number of blocks of\n\
+                          instructions to emit between literal pool\n\
+                          locations; implies --auto-litpools flag\n", stream);
 }
 
 \f
@@ -4728,6 +4795,8 @@ xtensa_mark_literal_pool_location (void)
   pool_location = frag_now;
   frag_now->tc_frag_data.lit_frchain = frchain_now;
   frag_now->tc_frag_data.literal_frag = frag_now;
+  /* Just record this frag.  */
+  xtensa_maybe_create_literal_pool_frag (FALSE, FALSE);
   frag_variant (rs_machine_dependent, 0, 0,
                RELAX_LITERAL_POOL_BEGIN, NULL, 0, NULL);
   xtensa_set_frag_assembly_state (frag_now);
@@ -4832,6 +4901,31 @@ get_expanded_loop_offset (xtensa_opcode opcode)
 static fragS *
 get_literal_pool_location (segT seg)
 {
+  struct litpool_seg *lps = litpool_seg_list.next;
+  struct litpool_frag *lpf;
+  for ( ; lps && lps->seg->id != seg->id; lps = lps->next)
+    ;
+  if (lps)
+    {
+      for (lpf = lps->frag_list.prev; lpf->fragP; lpf = lpf->prev)
+       { /* Skip "candidates" for now.  */
+         if (lpf->fragP->fr_subtype == RELAX_LITERAL_POOL_BEGIN &&
+             lpf->priority == 1)
+           return lpf->fragP;
+       }
+      /* Must convert a lower-priority pool.  */
+      for (lpf = lps->frag_list.prev; lpf->fragP; lpf = lpf->prev)
+       {
+         if (lpf->fragP->fr_subtype == RELAX_LITERAL_POOL_BEGIN)
+           return lpf->fragP;
+       }
+      /* Still no match -- try for a low priority pool.  */
+      for (lpf = lps->frag_list.prev; lpf->fragP; lpf = lpf->prev)
+       {
+         if (lpf->fragP->fr_subtype == RELAX_LITERAL_POOL_CANDIDATE_BEGIN)
+           return lpf->fragP;
+       }
+    }
   return seg_info (seg)->tc_segment_info_data.literal_pool_loc;
 }
 
@@ -7098,6 +7192,11 @@ xg_assemble_vliw_tokens (vliw_insn *vinsn)
       frag_now->tc_frag_data.slot_symbols[slot] = tinsn->symbol;
       frag_now->tc_frag_data.slot_offsets[slot] = tinsn->offset;
       frag_now->tc_frag_data.literal_frags[slot] = tinsn->literal_frag;
+      if (tinsn->opcode == xtensa_l32r_opcode)
+       {
+         frag_now->tc_frag_data.literal_frags[slot] =
+                 tinsn->tok[1].X_add_symbol->sy_frag;
+       }
       if (tinsn->literal_space != 0)
        xg_assemble_literal_space (tinsn->literal_space, slot);
       frag_now->tc_frag_data.free_reg[slot] = tinsn->extra_arg;
@@ -7170,6 +7269,8 @@ xg_assemble_vliw_tokens (vliw_insn *vinsn)
                    frag_now->fr_symbol, frag_now->fr_offset, NULL);
          xtensa_set_frag_assembly_state (frag_now);
          xtensa_maybe_create_trampoline_frag ();
+         /* Always create one here.  */
+         xtensa_maybe_create_literal_pool_frag (TRUE, FALSE);
        }
       else if (is_branch && do_align_targets ())
        {
@@ -7314,11 +7415,18 @@ xtensa_check_frag_count (void)
       clear_frag_count ();
       unreachable_count = 0;
     }
+
+  /* We create an area for a possible literal pool every N (default 5000)
+     frags or so.  */
+  xtensa_maybe_create_literal_pool_frag (TRUE, TRUE);
 }
 
 static xtensa_insnbuf trampoline_buf = NULL;
 static xtensa_insnbuf trampoline_slotbuf = NULL;
 
+static xtensa_insnbuf litpool_buf = NULL;
+static xtensa_insnbuf litpool_slotbuf = NULL;
+
 #define TRAMPOLINE_FRAG_SIZE 3000
 
 static void
@@ -7410,6 +7518,135 @@ dump_trampolines (void)
     }
 }
 
+static void dump_litpools (void) __attribute__ ((unused));
+
+static void
+dump_litpools (void)
+{
+  struct litpool_seg *lps = litpool_seg_list.next;
+  struct litpool_frag *lpf;
+
+  for ( ; lps ; lps = lps->next )
+    {
+      printf("litpool seg %s\n", lps->seg->name);
+      for ( lpf = lps->frag_list.next; lpf->fragP; lpf = lpf->next )
+       {
+         fragS *litfrag = lpf->fragP->fr_next;
+         int count = 0;
+         while (litfrag && litfrag->fr_subtype != RELAX_LITERAL_POOL_END)
+           {
+             if (litfrag->fr_fix == 4)
+               count++;
+             litfrag = litfrag->fr_next;
+           }
+         printf("   %ld <%d:%d> (%d) [%d]: ",
+                lpf->addr, lpf->priority, lpf->original_priority,
+                lpf->fragP->fr_line, count);
+         //dump_frag(lpf->fragP);
+       }
+    }
+}
+
+static void
+xtensa_maybe_create_literal_pool_frag (bfd_boolean create,
+                                      bfd_boolean only_if_needed)
+{
+  struct litpool_seg *lps = litpool_seg_list.next;
+  fragS *fragP;
+  struct litpool_frag *lpf;
+  bfd_boolean needed = FALSE;
+
+  if (use_literal_section || !auto_litpools)
+    return;
+
+  for ( ; lps ; lps = lps->next )
+    {
+      if (lps->seg == now_seg)
+       break;
+    }
+
+  if (lps == NULL)
+    {
+      lps = (struct litpool_seg *)xcalloc (sizeof (struct litpool_seg), 1);
+      lps->next = litpool_seg_list.next;
+      litpool_seg_list.next = lps;
+      lps->seg = now_seg;
+      lps->frag_list.next = &lps->frag_list;
+      lps->frag_list.prev = &lps->frag_list;
+    }
+
+  lps->frag_count++;
+
+  if (create)
+    {
+      if (only_if_needed)
+       {
+         if (past_xtensa_end || !use_transform() ||
+             frag_now->tc_frag_data.is_no_transform)
+           {
+             return;
+           }
+         if (auto_litpool_limit <= 0)
+           {
+             /* Don't create a litpool based only on frag count.  */
+             return;
+           }
+         else if (lps->frag_count > auto_litpool_limit)
+           {
+             needed = TRUE;
+           }
+         else
+           {
+             return;
+           }
+       }
+      else
+       {
+         needed = TRUE;
+       }
+    }
+
+  if (needed)
+    {
+      int size = (only_if_needed) ? 3 : 0; /* Space for a "j" insn.  */
+      /* Create a potential site for a literal pool.  */
+      frag_wane (frag_now);
+      frag_new (0);
+      xtensa_set_frag_assembly_state (frag_now);
+      fragP = frag_now;
+      fragP->tc_frag_data.lit_frchain = frchain_now;
+      fragP->tc_frag_data.literal_frag = fragP;
+      frag_var (rs_machine_dependent, size, size,
+                   (only_if_needed) ?
+                       RELAX_LITERAL_POOL_CANDIDATE_BEGIN :
+                       RELAX_LITERAL_POOL_BEGIN,
+                   NULL, 0, NULL);
+      frag_now->tc_frag_data.lit_seg = now_seg;
+      frag_variant (rs_machine_dependent, 0, 0,
+                   RELAX_LITERAL_POOL_END, NULL, 0, NULL);
+      xtensa_set_frag_assembly_state (frag_now);
+    }
+  else
+    {
+      /* RELAX_LITERAL_POOL_BEGIN frag is being created;
+        just record it here.  */
+      fragP = frag_now;
+    }
+
+  lpf = (struct litpool_frag *)xmalloc(sizeof (struct litpool_frag));
+  /* Insert at tail of circular list.  */
+  lpf->addr = 0;
+  lps->frag_list.prev->next = lpf;
+  lpf->next = &lps->frag_list;
+  lpf->prev = lps->frag_list.prev;
+  lps->frag_list.prev = lpf;
+  lpf->fragP = fragP;
+  lpf->priority = (needed) ? (only_if_needed) ? 3 : 2 : 1;
+  lpf->original_priority = lpf->priority;
+
+  lps->frag_count = 0;
+}
+
 static void
 xtensa_cleanup_align_frags (void)
 {
@@ -9029,7 +9266,41 @@ xtensa_relax_frag (fragS *fragP, long stretch, int *stretched_p)
       break;
 
     case RELAX_LITERAL_POOL_BEGIN:
+      if (fragP->fr_var != 0)
+       {
+         /* We have a converted "candidate" literal pool;
+            assemble a jump around it.  */
+         TInsn insn;
+         if (!litpool_slotbuf)
+           {
+             litpool_buf = xtensa_insnbuf_alloc (isa);
+             litpool_slotbuf = xtensa_insnbuf_alloc (isa);
+           }
+         new_stretch += 3;
+         fragP->tc_frag_data.relax_seen = FALSE; /* Need another pass.  */
+         fragP->tc_frag_data.is_insn = TRUE;
+         tinsn_init (&insn);
+         insn.insn_type = ITYPE_INSN;
+         insn.opcode = xtensa_j_opcode;
+         insn.ntok = 1;
+         set_expr_symbol_offset (&insn.tok[0], fragP->fr_symbol,
+                                 fragP->fr_fix);
+         fmt = xg_get_single_format (xtensa_j_opcode);
+         tinsn_to_slotbuf (fmt, 0, &insn, litpool_slotbuf);
+         xtensa_format_set_slot (isa, fmt, 0, litpool_buf, litpool_slotbuf);
+         xtensa_insnbuf_to_chars (isa, litpool_buf,
+                                  (unsigned char *)fragP->fr_literal +
+                                  fragP->fr_fix, 3);
+         fragP->fr_fix += 3;
+         fragP->fr_var -= 3;
+         /* Add a fix-up.  */
+         fix_new (fragP, 0, 3, fragP->fr_symbol, 0, TRUE,
+                  BFD_RELOC_XTENSA_SLOT0_OP);
+       }
+      break;
+
     case RELAX_LITERAL_POOL_END:
+    case RELAX_LITERAL_POOL_CANDIDATE_BEGIN:
     case RELAX_MAYBE_UNREACHABLE:
     case RELAX_MAYBE_DESIRE_ALIGN:
       /* No relaxation required.  */
@@ -10789,12 +11060,115 @@ xtensa_move_literals (void)
   segT dest_seg;
   fixS *fix, *next_fix, **fix_splice;
   sym_list *lit;
+  struct litpool_seg *lps;
 
   mark_literal_frags (literal_head->next);
 
   if (use_literal_section)
     return;
 
+  /* Assign addresses (rough estimates) to the potential literal pool locations
+     and create new ones if the gaps are too large.  */
+
+  for (lps = litpool_seg_list.next; lps; lps = lps->next)
+    {
+      frchainS *frchP = seg_info (lps->seg)->frchainP;
+      struct litpool_frag *lpf = lps->frag_list.next;
+      addressT addr = 0;
+
+      for ( ; frchP; frchP = frchP->frch_next)
+       {
+         fragS *fragP;
+         for (fragP = frchP->frch_root; fragP; fragP = fragP->fr_next)
+           {
+             if (lpf && fragP == lpf->fragP)
+               {
+                 gas_assert(fragP->fr_type == rs_machine_dependent &&
+                            (fragP->fr_subtype == RELAX_LITERAL_POOL_BEGIN ||
+                             fragP->fr_subtype == RELAX_LITERAL_POOL_CANDIDATE_BEGIN));
+                 /* Found a litpool location.  */
+                 lpf->addr = addr;
+                 lpf = lpf->next;
+               }
+             if (fragP->fr_type == rs_machine_dependent &&
+                 fragP->fr_subtype == RELAX_SLOTS)
+               {
+                 int slot;
+                 for (slot = 0; slot < MAX_SLOTS; slot++)
+                   {
+                     if (fragP->tc_frag_data.literal_frags[slot])
+                       {
+                         /* L32R; point its literal to the nearest litpool
+                            preferring non-"candidate" positions to avoid
+                            the jump-around.  */
+                         fragS *litfrag = fragP->tc_frag_data.literal_frags[slot];
+                         struct litpool_frag *lp = lpf->prev;
+                         if (!lp->fragP)
+                           {
+                             break;
+                           }
+                         while (lp->fragP->fr_subtype ==
+                                RELAX_LITERAL_POOL_CANDIDATE_BEGIN)
+                           {
+                             lp = lp->prev;
+                             if (lp->fragP == NULL)
+                               {
+                                 /* End of list; have to bite the bullet.
+                                    Take the nearest.  */
+                                 lp = lpf->prev;
+                                 break;
+                               }
+                             /* Does it (conservatively) reach?  */
+                             if (addr - lp->addr <= 128 * 1024)
+                               {
+                                 if (lp->fragP->fr_subtype == RELAX_LITERAL_POOL_BEGIN)
+                                   {
+                                     /* Found a good one.  */
+                                     break;
+                                   }
+                                 else if (lp->prev->fragP &&
+                                          addr - lp->prev->addr > 128 * 1024)
+                                   {
+                                     /* This is still a "candidate" but the next one
+                                        will be too far away, so revert to the nearest
+                                        one, convert it and add the jump around.  */
+                                     fragS *poolbeg;
+                                     fragS *poolend;
+                                     symbolS *lsym;
+                                     char label[10 + 2 * sizeof (fragS *)];
+                                     lp = lpf->prev;
+                                     poolbeg = lp->fragP;
+                                     lp->priority = 1;
+                                     poolbeg->fr_subtype = RELAX_LITERAL_POOL_BEGIN;
+                                     poolend = poolbeg->fr_next;
+                                     gas_assert (poolend->fr_type == rs_machine_dependent &&
+                                                 poolend->fr_subtype == RELAX_LITERAL_POOL_END);
+                                     /* Create a local symbol pointing to the
+                                        end of the pool.  */
+                                     sprintf (label, ".L0_LT_%p", poolbeg);
+                                     lsym = (symbolS *)local_symbol_make (label, lps->seg,
+                                                                          0, poolend);
+                                     poolbeg->fr_symbol = lsym;
+                                     /* Rest is done in xtensa_relax_frag.  */
+                                   }
+                               }
+                           }
+                         if (! litfrag->tc_frag_data.literal_frag)
+                           {
+                             /* Take earliest use of this literal to avoid
+                                forward refs.  */
+                             litfrag->tc_frag_data.literal_frag = lp->fragP;
+                           }
+                       }
+                   }
+               }
+             addr += fragP->fr_fix;
+             if (fragP->fr_type == rs_fill)
+               addr += fragP->fr_offset;
+           }
+       }
+    }
+
   for (segment = literal_head->next; segment; segment = segment->next)
     {
       /* Keep the literals for .init and .fini in separate sections.  */
@@ -10839,9 +11213,6 @@ xtensa_move_literals (void)
       while (search_frag != frag_now)
        {
          next_frag = search_frag->fr_next;
-
-         /* First, move the frag out of the literal section and
-            to the appropriate place.  */
          if (search_frag->tc_frag_data.literal_frag)
            {
              literal_pool = search_frag->tc_frag_data.literal_frag;
@@ -10849,8 +11220,56 @@ xtensa_move_literals (void)
              frchain_to = literal_pool->tc_frag_data.lit_frchain;
              gas_assert (frchain_to);
            }
+
+         if (search_frag->fr_type == rs_fill && search_frag->fr_fix == 0)
+           {
+             /* Skip empty fill frags.  */
+             *frag_splice = next_frag;
+             search_frag = next_frag;
+             continue;
+           }
+
+         if (search_frag->fr_type == rs_align)
+           {
+             /* Skip alignment frags, because the pool as a whole will be
+                aligned if used, and we don't want to force alignment if the
+                pool is unused.  */
+             *frag_splice = next_frag;
+             search_frag = next_frag;
+             continue;
+           }
+
+         /* First, move the frag out of the literal section and
+            to the appropriate place.  */
+
+         /* Insert an aligmnent frag at start of pool.  */
+         if (literal_pool->fr_next->fr_type == rs_machine_dependent &&
+             literal_pool->fr_next->fr_subtype == RELAX_LITERAL_POOL_END)
+           {
+             segT pool_seg = literal_pool->fr_next->tc_frag_data.lit_seg;
+             emit_state prev_state;
+             fragS *prev_frag;
+             fragS *align_frag;
+             xtensa_switch_section_emit_state (&prev_state, pool_seg, 0);
+             prev_frag = frag_now;
+             frag_variant (rs_fill, 0, 0, 0, NULL, 0, NULL);
+             align_frag = frag_now;
+             frag_align (2, 0, 0);
+             /* Splice it into the right place.  */
+             prev_frag->fr_next = align_frag->fr_next;
+             align_frag->fr_next = literal_pool->fr_next;
+             literal_pool->fr_next = align_frag;
+             /* Insert after this one.  */
+             literal_pool->tc_frag_data.literal_frag = align_frag;
+             xtensa_restore_emit_state (&prev_state);
+           }
          insert_after = literal_pool->tc_frag_data.literal_frag;
          dest_seg = insert_after->fr_next->tc_frag_data.lit_seg;
+         /* Skip align frag.  */
+         if (insert_after->fr_next->fr_type == rs_align)
+           {
+             insert_after = insert_after->fr_next;
+           }
 
          *frag_splice = next_frag;
          search_frag->fr_next = insert_after->fr_next;
@@ -11014,7 +11433,10 @@ xtensa_switch_to_non_abs_literal_fragment (emit_state *result)
       && !recursive
       && !is_init && ! is_fini)
     {
-      as_bad (_("literal pool location required for text-section-literals; specify with .literal_position"));
+      if (!auto_litpools)
+       {
+         as_bad (_("literal pool location required for text-section-literals; specify with .literal_position"));
+       }
 
       /* When we mark a literal pool location, we want to put a frag in
         the literal pool that points to it.  But to do that, we want to
index b2e43fa5c295b9597505329902ecf5a0d2baffb6..290d902d9ca55f497044b06ffb2601b94cd10f9b 100644 (file)
@@ -124,6 +124,7 @@ enum xtensa_relax_statesE
 
   RELAX_LITERAL_POOL_BEGIN,
   RELAX_LITERAL_POOL_END,
+  RELAX_LITERAL_POOL_CANDIDATE_BEGIN,
   /* Technically these are not relaxations at all but mark a location
      to store literals later.  Note that fr_var stores the frchain for
      BEGIN frags and fr_var stores now_seg for END frags.  */
index e3b965c8cf7dde56f557de1346717131e5955009..dae7424e6d096ea4d0721558c22a200dbb1243ef 100644 (file)
@@ -555,7 +555,8 @@ gcc(1), ld(1), and the Info entries for @file{binutils} and @file{ld}.
 @ifset XTENSA
 
 @emph{Target Xtensa options:}
- [@b{--[no-]text-section-literals}] [@b{--[no-]absolute-literals}]
+ [@b{--[no-]text-section-literals}] [@b{--[no-]auto-litpools}]
+ [@b{--[no-]absolute-literals}]
  [@b{--[no-]target-align}] [@b{--[no-]longcalls}]
  [@b{--[no-]transform}]
  [@b{--rename-section} @var{oldname}=@var{newname}]
index 7019f8478ad9198c2ce74f96af2782a638661681..26155c4eb0de0bf161c2656757652baffc17b86c 100644 (file)
@@ -43,9 +43,30 @@ placed in a data RAM/ROM.  With @samp{--text-@-section-@-literals}, the
 literals are interspersed in the text section in order to keep them as
 close as possible to their references.  This may be necessary for large
 assembly files, where the literals would otherwise be out of range of the
-@code{L32R} instructions in the text section.  These options only affect
+@code{L32R} instructions in the text section.  Literals are grouped into
+pools following @code{.literal_position} directives or preceding
+@code{ENTRY} instructions.  These options only affect literals referenced
+via PC-relative @code{L32R} instructions; literals for absolute mode
+@code{L32R} instructions are handled separately.
+@xref{Literal Directive, ,literal}.
+
+@item --auto-litpools | --no-auto-litpools
+@kindex --auto-litpools
+@kindex --no-auto-litpools
+Control the treatment of literal pools.  The default is
+@samp{--no-@-auto-@-litpools}, which in the absence of
+@samp{--text-@-section-@-literals} places literals in separate sections
+in the output file.  This allows the literal pool to be placed in a data
+RAM/ROM.  With @samp{--auto-@-litpools}, the literals are interspersed
+in the text section in order to keep them as close as possible to their
+references, explicit @code{.literal_position} directives are not
+required.  This may be necessary for very large functions, where single
+literal pool at the beginning of the function may not be reachable by
+@code{L32R} instructions at the end.  These options only affect
 literals referenced via PC-relative @code{L32R} instructions; literals
 for absolute mode @code{L32R} instructions are handled separately.
+When used together with @samp{--text-@-section-@-literals},
+@samp{--auto-@-litpools} takes precedence.
 @xref{Literal Directive, ,literal}.
 
 @item --absolute-literals | --no-absolute-literals
index f8ea3a24fcf25ada16f4810bba4b4451f692aae6..f4601b82f127bb4b2faf26ad9d340b9d735e3ab3 100644 (file)
@@ -1,3 +1,11 @@
+2015-08-12  Max Filippov  <jcmvbkbc@gmail.com>
+
+       * gas/xtensa/all.exp: Add auto-litpools to the list of xtensa
+       tests.
+       * gas/xtensa/auto-litpools.s: New file: auto-litpools test.
+       * gas/xtensa/auto-litpools.s: New file: auto-litpools test
+       result pattern.
+
 2015-08-12  Simon Dardis  <simon.dardis@imgtec.com>
 
        * gas/mips/elf-rel23.d: Update test.
index d197ec86fc8ae0f913f469308e13a04c9e27f59e..db39629c6f924e566dbc9d5c98805ba8b9bc52e9 100644 (file)
@@ -100,6 +100,7 @@ if [istarget xtensa*-*-*] then {
     run_dump_test "jlong"
     run_dump_test "trampoline"
     run_dump_test "first_frag_align"
+    run_dump_test "auto-litpools"
 }
 
 if [info exists errorInfo] then {
diff --git a/gas/testsuite/gas/xtensa/auto-litpools.d b/gas/testsuite/gas/xtensa/auto-litpools.d
new file mode 100644 (file)
index 0000000..4d1a690
--- /dev/null
@@ -0,0 +1,12 @@
+#as: --auto-litpools
+#objdump: -d
+#name: auto literal pool placement
+
+.*: +file format .*xtensa.*
+#...
+.*4:.*l32r.a2, 0 .*
+#...
+.*3e437:.*j.3e440 .*
+#...
+.*40750:.*l32r.a2, 3e43c .*
+#...
diff --git a/gas/testsuite/gas/xtensa/auto-litpools.s b/gas/testsuite/gas/xtensa/auto-litpools.s
new file mode 100644 (file)
index 0000000..9a5b26b
--- /dev/null
@@ -0,0 +1,13 @@
+       .text
+       .align  4
+       .literal        .L0, 0x12345
+       .literal        .L1, 0x12345
+
+f:
+       l32r    a2, .L0
+       .rep    44000
+       _nop
+       _nop
+       .endr
+       l32r    a2, .L1
+       ret