Re: [PATCH] ld: fix ABSOLUTE for general expressions

[Alan Modra <amodra at gmail dot com>]

Like all changes that affect script expressions there is quite a good
chance that someone is relying on the old behaviour.  For example,
Jakub called the maxpage3b behaviour a "feature" in
https://sourceware.org/ml/binutils/2007-01/msg00181.html
Well, that one seems quite clearly a bug to me.  I'm actually more
worried about "absolute (<number>)" inside output section statements,
ie. the behaviour that Tristan thinks should be changed.  Oh well,
let's see who screams.

---
Early expression evaluation

Folding a constant expression early can lead to loss of tokens, eg.
ABSOLUTE, that are significant in ld's horrible context sensitive
expression evaluation.  Also, MAXPAGESIZE and other "constants" may
not have taken values specified on the command line, leading to the
wrong value being cached.

	* ldexp.c (exp_unop, exp_binop, exp_trinop, exp_nameop): Don't
	fold expression.
	* testsuite/ld-elf/maxpage3b.d: Expect correct maxpagesize.

diff --git a/ld/ldexp.c b/ld/ldexp.c
index 68c4bc5..a560643 100644
--- a/ld/ldexp.c
+++ b/ld/ldexp.c
@@ -1255,80 +1255,55 @@ exp_fold_tree_no_dot (etree_type *tree)
 etree_type *
 exp_binop (int code, etree_type *lhs, etree_type *rhs)
 {
-  etree_type value, *new_e;
-
-  value.type.node_code = code;
-  value.type.filename = lhs->type.filename;
-  value.type.lineno = lhs->type.lineno;
-  value.binary.lhs = lhs;
-  value.binary.rhs = rhs;
-  value.type.node_class = etree_binary;
-  exp_fold_tree_no_dot (&value);
-  if (expld.result.valid_p)
-    return exp_intop (expld.result.value);
-
-  new_e = (etree_type *) stat_alloc (sizeof (new_e->binary));
-  memcpy (new_e, &value, sizeof (new_e->binary));
+  etree_type *new_e = (etree_type *) stat_alloc (sizeof (new_e->binary));
+
+  new_e->type.node_code = code;
+  new_e->type.filename = lhs->type.filename;
+  new_e->type.lineno = lhs->type.lineno;
+  new_e->binary.lhs = lhs;
+  new_e->binary.rhs = rhs;
+  new_e->type.node_class = etree_binary;
   return new_e;
 }
 
 etree_type *
 exp_trinop (int code, etree_type *cond, etree_type *lhs, etree_type *rhs)
 {
-  etree_type value, *new_e;
-
-  value.type.node_code = code;
-  value.type.filename = cond->type.filename;
-  value.type.lineno = cond->type.lineno;
-  value.trinary.lhs = lhs;
-  value.trinary.cond = cond;
-  value.trinary.rhs = rhs;
-  value.type.node_class = etree_trinary;
-  exp_fold_tree_no_dot (&value);
-  if (expld.result.valid_p)
-    return exp_intop (expld.result.value);
-
-  new_e = (etree_type *) stat_alloc (sizeof (new_e->trinary));
-  memcpy (new_e, &value, sizeof (new_e->trinary));
+  etree_type *new_e = (etree_type *) stat_alloc (sizeof (new_e->trinary));
+
+  new_e->type.node_code = code;
+  new_e->type.filename = cond->type.filename;
+  new_e->type.lineno = cond->type.lineno;
+  new_e->trinary.lhs = lhs;
+  new_e->trinary.cond = cond;
+  new_e->trinary.rhs = rhs;
+  new_e->type.node_class = etree_trinary;
   return new_e;
 }
 
 etree_type *
 exp_unop (int code, etree_type *child)
 {
-  etree_type value, *new_e;
-
-  value.unary.type.node_code = code;
-  value.unary.type.filename = child->type.filename;
-  value.unary.type.lineno = child->type.lineno;
-  value.unary.child = child;
-  value.unary.type.node_class = etree_unary;
-  exp_fold_tree_no_dot (&value);
-  if (expld.result.valid_p)
-    return exp_intop (expld.result.value);
+  etree_type *new_e = (etree_type *) stat_alloc (sizeof (new_e->unary));
 
-  new_e = (etree_type *) stat_alloc (sizeof (new_e->unary));
-  memcpy (new_e, &value, sizeof (new_e->unary));
+  new_e->unary.type.node_code = code;
+  new_e->unary.type.filename = child->type.filename;
+  new_e->unary.type.lineno = child->type.lineno;
+  new_e->unary.child = child;
+  new_e->unary.type.node_class = etree_unary;
   return new_e;
 }
 
 etree_type *
 exp_nameop (int code, const char *name)
 {
-  etree_type value, *new_e;
-
-  value.name.type.node_code = code;
-  value.name.type.filename = ldlex_filename ();
-  value.name.type.lineno = lineno;
-  value.name.name = name;
-  value.name.type.node_class = etree_name;
-
-  exp_fold_tree_no_dot (&value);
-  if (expld.result.valid_p)
-    return exp_intop (expld.result.value);
+  etree_type *new_e = (etree_type *) stat_alloc (sizeof (new_e->name));
 
-  new_e = (etree_type *) stat_alloc (sizeof (new_e->name));
-  memcpy (new_e, &value, sizeof (new_e->name));
+  new_e->name.type.node_code = code;
+  new_e->name.type.filename = ldlex_filename ();
+  new_e->name.type.lineno = lineno;
+  new_e->name.name = name;
+  new_e->name.type.node_class = etree_name;
   return new_e;
 
 }
diff --git a/ld/testsuite/ld-elf/maxpage3b.d b/ld/testsuite/ld-elf/maxpage3b.d
index 4bee0ec..62b50c9 100644
--- a/ld/testsuite/ld-elf/maxpage3b.d
+++ b/ld/testsuite/ld-elf/maxpage3b.d
@@ -4,7 +4,8 @@
 #target: x86_64-*-linux*
 
 #...
-  \[[ 0-9]+\] \.data[ \t]+PROGBITS[ \t]+0*200000[ \t]+[ \t0-9a-f]+WA?.*
+  \[[ 0-9]+\] \.data[ \t]+PROGBITS[ \t]+0*10000000[ \t]+[ \t0-9a-f]+WA?.*
 #...
   LOAD+.*0x10000000
+  LOAD+.*0x10000000
 #pass

-- 
Alan Modra
Australia Development Lab, IBM