Wed Jul 1 11:19:13 1998 Craig Burley <burley@gnu.org>

	Fix 980701-1.f (which was producing "unaligned trap"
	on an Alpha running GNU/Linux, as predicted):
	* equiv.c (ffeequiv_layout_local_): Don't bother
	coping with pre-padding of entire area while building
	it; do that instead after the building is done, and
	do it by modifying only the modulo field.  This covers
	the case of alignment stringency being increased without
	lowering the starting offset, unlike the previous changes,
	and even more elegantly than those.
	* target.c (ffetarget_align): Make sure alignments
	are non-zero, just in case.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@20875 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 62 insertions, 17 deletions

diff --git a/gcc/f/ChangeLog b/gcc/f/ChangeLog
index b4821f78632..9f8068f4702 100644
--- a/gcc/f/ChangeLog
+++ b/gcc/f/ChangeLog
@@ -1,3 +1,18 @@
+Wed Jul  1 11:19:13 1998  Craig Burley  <burley@gnu.org>
+
+	Fix 980701-1.f (which was producing "unaligned trap"
+	on an Alpha running GNU/Linux, as predicted):
+	* equiv.c (ffeequiv_layout_local_): Don't bother
+	coping with pre-padding of entire area while building
+	it; do that instead after the building is done, and
+	do it by modifying only the modulo field.  This covers
+	the case of alignment stringency being increased without
+	lowering the starting offset, unlike the previous changes,
+	and even more elegantly than those.
+
+	* target.c (ffetarget_align): Make sure alignments
+	are non-zero, just in case.
+
 Mon Jun 29 09:47:33 1998  Craig Burley  <burley@gnu.org>
 
 	Fix 980628-*.f:
diff --git a/gcc/f/equiv.c b/gcc/f/equiv.c
index 9fd856bd024..8c0975128c1 100644
--- a/gcc/f/equiv.c
+++ b/gcc/f/equiv.c
@@ -368,6 +368,7 @@ ffeequiv_layout_local_ (ffeequiv eq)
 	      ffestorag item_st;		/* Storage for var. */
 	      ffesymbol item_sym;		/* Var itself. */
 	      ffetargetOffset item_offset;	/* Offset for var from root. */
+	      ffetargetOffset new_size;
 
 	      item_exp = ffebld_head (item);
 	      item_sym = ffeequiv_symbol (item_exp);
@@ -433,28 +434,18 @@ ffeequiv_layout_local_ (ffeequiv eq)
 		}
 	      else if (item_offset < ffestorag_offset (st))
 		{
-		  ffetargetOffset new_size;
-
-		  /* First, calculate the initial padding necessary
-		     to preserve the current alignment/modulo requirements
-		     for the storage area.  */
-		  pad = (-item_offset) % ffestorag_alignment (st);
-		  if (pad != 0)
-		    pad = ffestorag_alignment (st) - pad;
-
-		  /* Increase size of equiv area to start for lower offset relative
-		     to root symbol.  */
+		  /* Increase size of equiv area to start for lower offset
+		     relative to root symbol.  */
 		  if (! ffetarget_offset_add (&new_size,
-					     (ffestorag_offset (st)
-					      - item_offset)
-					     + pad,
-					     ffestorag_size (st)))
+					      ffestorag_offset (st)
+					      - item_offset,
+					      ffestorag_size (st)))
 		    ffetarget_offset_overflow (ffesymbol_text (s));
 		  else
 		    ffestorag_set_size (st, new_size);
 
 		  ffestorag_set_symbol (st, item_sym);
-		  ffestorag_set_offset (st, item_offset - pad);
+		  ffestorag_set_offset (st, item_offset);
 
 #if FFEEQUIV_DEBUG
 		  fprintf (stderr, " [eq offset=%" ffetargetOffset_f
@@ -538,6 +529,42 @@ ffeequiv_layout_local_ (ffeequiv eq)
 
   ffeequiv_kill (eq);		/* Fully processed, no longer needed. */
 
+  /* If the offset for this storage area is zero (it cannot be positive),
+     that means the alignment/modulo info is already correct.  Otherwise,
+     the alignment info is correct, but the modulo info reflects a
+     zero offset, so fix it.  */
+
+  if (ffestorag_offset (st) < 0)
+    {
+      /* Calculate the initial padding necessary to preserve
+	 the alignment/modulo requirements for the storage area.
+	 These requirements are themselves kept track of in the
+	 record for the storage area as a whole, but really pertain
+	 to offset 0 of that area, which is where the root symbol
+	 was originally placed.
+
+	 The goal here is to have the offset and size for the area
+	 faithfully reflect the area itself, not extra requirements
+	 like alignment.  So to meet the alignment requirements,
+	 the modulo for the area should be set as if the area had an
+	 alignment requirement of alignment/0 and was aligned/padded
+	 downward to meet the alignment requirements of the area at
+	 offset zero, the amount of padding needed being the desired
+	 value for the modulo of the area.  */
+
+      alignment = ffestorag_alignment (st);
+      modulo = ffestorag_modulo (st);
+
+      /* Since we want to move the whole area *down* (lower memory
+	 addresses) as required by the alignment/modulo paid, negate
+	 the offset to ffetarget_align, which assumes aligning *up*
+	 is desired.  */
+      pad = ffetarget_align (&alignment, &modulo,
+			     - ffestorag_offset (st),
+			     alignment, 0);
+      ffestorag_set_modulo (st, pad);
+    }
+
   if (init)
     ffedata_gather (st);	/* Gather subordinate inits into one init. */
 }
diff --git a/gcc/f/target.c b/gcc/f/target.c
index 2244dbc1fad..5de05ff07ca 100644
--- a/gcc/f/target.c
+++ b/gcc/f/target.c
@@ -214,6 +214,9 @@ ffetarget_align (ffetargetAlign *updated_alignment,
   ffetargetAlign i;
   ffetargetAlign j;
 
+  assert (alignment > 0);
+  assert (*updated_alignment > 0);
+  
   assert (*updated_modulo < *updated_alignment);
   assert (modulo < alignment);
 
diff --git a/gcc/f/version.c b/gcc/f/version.c
index fbec2902f45..98e877b79c7 100644
--- a/gcc/f/version.c
+++ b/gcc/f/version.c
@@ -1 +1 @@
-char *ffe_version_string = "0.5.24-19980629";
+char *ffe_version_string = "0.5.24-19980701";