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Re: ALIGN directive showing different behavior than documented

On Tue, Jul 07, 2015 at 02:41:59PM +0100, Andre Vieira wrote:
> After some digging I found that the unary operator uses the expression
> '' whereas the binary operator uses 'lhs.value'. The first gives an
> absolute value, whereas the second seems to hold a relative value to the
> section start.

Right, lhs.value is evaluated from fold_name case NAME here:
      else if (tree->[0] == '.' && tree->[1] == 0)
	new_rel_from_abs (;

So the difference is that the unary operator is missing a conversion
from absolute to relative.  I think that is a bug since we say the
value of dot inside a section is relative to the start of the section.

I wonder how many scripts rely on the old behaviour?  If I don't hear
any objections to this change, I'll install the following in a day or

	* ldexp.c (align_dot_val): New function.
	(fold_unary <ALIGN_K, NEXT>): Use it.

diff --git a/ld/ldexp.c b/ld/ldexp.c
index a5192b1..2c0fe5a 100644
--- a/ld/ldexp.c
+++ b/ld/ldexp.c
@@ -257,6 +257,14 @@ new_rel_from_abs (bfd_vma value)
   expld.result.section = s;
+static void
+align_dot_val (bfd_vma align)
+  bfd_vma base = expld.section->vma;
+  new_rel_from_abs (base + align_n ( - base, align));
 /* New-function for the definedness hash table.  */
 static struct bfd_hash_entry *
@@ -335,7 +343,7 @@ fold_unary (etree_type *tree)
 	case ALIGN_K:
 	  if (expld.phase != lang_first_phase_enum)
-	    new_rel_from_abs (align_n (, expld.result.value));
+	    align_dot_val (expld.result.value);
 	    expld.result.valid_p = FALSE;
@@ -365,7 +373,7 @@ fold_unary (etree_type *tree)
 	  if (expld.phase != lang_first_phase_enum)
 	      make_abs ();
-	      expld.result.value = align_n (, expld.result.value);
+	      align_dot_val (expld.result.value);
 	    expld.result.valid_p = FALSE;

Alan Modra
Australia Development Lab, IBM

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