From 978adaaa4cd3921842e2be8a31c05f081fb17fcf Mon Sep 17 00:00:00 2001
From: Max Filippov <jcmvbkbc@gmail.com>
Date: Wed, 29 Jul 2015 17:42:54 +0300
Subject: [PATCH] xtensa: add --auto-litpools option

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.

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.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
Backported from: b46824bd49648c575372e6d9bc6a6defeabd6ed5
Changes to ChangeLogs and documentation are dropped.

 gas/config/tc-xtensa.c                   | 432 ++++++++++++++++++++++++++++++-
 gas/config/tc-xtensa.h                   |   1 +
 gas/testsuite/gas/xtensa/all.exp         |   1 +
 gas/testsuite/gas/xtensa/auto-litpools.d |  12 +
 gas/testsuite/gas/xtensa/auto-litpools.s |  13 +
 5 files changed, 454 insertions(+), 5 deletions(-)
 create mode 100644 gas/testsuite/gas/xtensa/auto-litpools.d
 create mode 100644 gas/testsuite/gas/xtensa/auto-litpools.s

diff --git a/gas/config/tc-xtensa.c b/gas/config/tc-xtensa.c
index 7311a05..b8b1e7d 100644
--- a/gas/config/tc-xtensa.c
+++ b/gas/config/tc-xtensa.c
@@ -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);
 }
 
 
@@ -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
diff --git a/gas/config/tc-xtensa.h b/gas/config/tc-xtensa.h
index b2e43fa..290d902 100644
--- a/gas/config/tc-xtensa.h
+++ b/gas/config/tc-xtensa.h
@@ -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.  */
diff --git a/gas/testsuite/gas/xtensa/all.exp b/gas/testsuite/gas/xtensa/all.exp
index d197ec8..db39629 100644
--- a/gas/testsuite/gas/xtensa/all.exp
+++ b/gas/testsuite/gas/xtensa/all.exp
@@ -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
index 0000000..4d1a690
--- /dev/null
+++ b/gas/testsuite/gas/xtensa/auto-litpools.d
@@ -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
index 0000000..9a5b26b
--- /dev/null
+++ b/gas/testsuite/gas/xtensa/auto-litpools.s
@@ -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
-- 
1.8.1.4