gdb: add target_ops::supports_displaced_step

[deliverable/binutils-gdb.git] / gas / frags.c

diff --git a/gas/frags.c b/gas/frags.c
index a9fc003fbdf05b1d6dc9e0384367d108e84aca17..c926ec3ba1ea5a92ca9966306c889ee27d95ea80 100644 (file)
--- a/gas/frags.c
+++ b/gas/frags.c
@@ -1,5 +1,5 @@
 /* frags.c - manage frags -
-   Copyright (C) 1987-2019 Free Software Foundation, Inc.
+   Copyright (C) 1987-2020 Free Software Foundation, Inc.
 
    This file is part of GAS, the GNU Assembler.
 
@@ -89,9 +89,9 @@ frag_alloc (struct obstack *ob)
 }
 \f
 /* Try to augment current frag by nchars chars.
-   If there is no room, close of the current frag with a ".fill 0"
-   and begin a new frag. Unless the new frag has nchars chars available
-   do not return. Do not set up any fields of *now_frag.  */
+   If there is no room, close off the current frag with a ".fill 0"
+   and begin a new frag.  Then loop until the new frag has at least
+   nchars chars available.  Does not set up any fields in frag_now.  */
 
 void
 frag_grow (size_t nchars)
@@ -395,7 +395,12 @@ frag_now_fix_octets (void)
 addressT
 frag_now_fix (void)
 {
-  return frag_now_fix_octets () / OCTETS_PER_BYTE;
+  /* Symbols whose section has SEC_ELF_OCTETS set,
+     resolve to octets instead of target bytes.  */
+  if (now_seg->flags & SEC_OCTETS)
+    return frag_now_fix_octets ();
+  else
+    return frag_now_fix_octets () / OCTETS_PER_BYTE;
 }
 
 void
@@ -462,3 +467,58 @@ frag_offset_fixed_p (const fragS *frag1, const fragS *frag2, offsetT *offset)
 
   return FALSE;
 }
+
+/* Return TRUE if we can determine whether FRAG2 OFF2 appears after
+   (strict >, not >=) FRAG1 OFF1, assuming it is not before.  Set
+   *OFFSET so that resolve_expression will resolve an O_gt operation
+   between them to false (0) if they are guaranteed to be at the same
+   location, or to true (-1) if they are guaranteed to be at different
+   locations.  Return FALSE conservatively, e.g. if neither result can
+   be guaranteed (yet).
+
+   They are known to be in the same segment, and not the same frag
+   (this is a fallback for frag_offset_fixed_p, that always takes care
+   of this case), and it is expected (from the uses this is designed
+   to simplify, namely location view increments) that frag2 is
+   reachable from frag1 following the fr_next links, rather than the
+   other way round.  */
+
+bfd_boolean
+frag_gtoffset_p (valueT off2, const fragS *frag2,
+                valueT off1, const fragS *frag1, offsetT *offset)
+{
+  /* Insanity check.  */
+  if (frag2 == frag1 || off1 > frag1->fr_fix)
+    return FALSE;
+
+  /* If the first symbol offset is at the end of the first frag and
+     the second symbol offset at the beginning of the second frag then
+     it is possible they are at the same address.  Go looking for a
+     non-zero fr_fix in any frag between these frags.  If found then
+     we can say the O_gt result will be true.  If no such frag is
+     found we assume that frag1 or any of the following frags might
+     have a variable tail and thus the answer is unknown.  This isn't
+     strictly true; some frags don't have a variable tail, but it
+     doesn't seem worth optimizing for those cases.  */
+  const fragS *frag = frag1;
+  offsetT delta = off2 - off1;
+  for (;;)
+    {
+      delta += frag->fr_fix;
+      frag = frag->fr_next;
+      if (frag == frag2)
+       {
+         if (delta == 0)
+           return FALSE;
+         break;
+       }
+      /* If we run off the end of the frag chain then we have a case
+        where frag2 is not after frag1, ie. an O_gt expression not
+        created for .loc view.  */
+      if (frag == NULL)
+       return FALSE;
+    }
+
+  *offset = (off2 - off1 - delta) * OCTETS_PER_BYTE;
+  return TRUE;
+}