Delay converting linker script defined symbols from absolute

Giving linker script symbols defined outside of output sections a
section-relative value early, leads to them being used in expressions
as if they were defined inside an output section.  This can mean loss
of the section VMA, and wrong results.

ld/
	PR ld/18963
	* ldexp.h (struct ldexp_control): Add rel_from_abs.
	(ldexp_finalize_syms): Declare.
	* ldexp.c (new_rel_from_abs): Keep absolute for expressions
	outside of output section statements.  Set rel_from_abs.
	(make_abs, exp_fold_tree, exp_fold_tree_no_dot): Clear rel_from_abs.
	(struct definedness_hash_entry): Add final_sec, and comment.
	(update_definedness): Set final_sec.
	(set_sym_sections, ldexp_finalize_syms): New functions.
	* ldlang.c (lang_process): Call ldexp_finalize_syms.
ld/testsuite
	PR ld/18963
	* ld-scripts/pr18963.d,
	* ld-scripts/pr18963.t: New test.
	* ld-scripts/expr.exp: Run it.
	* ld-elf/provide-hidden-2.ld: Explicitly make "dot" absolute.
	* ld-mips-elf/gp-hidden.sd: Don't care about _gp section.
	* ld-mips-elf/no-shared-1-n32.d: Don't care about symbol shown at
	start of .data section.
	* ld-mips-elf/no-shared-1-n64.d: Likewise.
	* ld-mips-elf/no-shared-1-o32.d: Likewise.

1 files changed, 9 insertions, 0 deletions

diff --git a/ld/ldexp.h b/ld/ldexp.h
index f61df6b..bea8045 100644
--- a/ld/ldexp.h
+++ b/ld/ldexp.h
@@ -138,6 +138,14 @@ struct ldexp_control {
 
   /* Principally used for diagnostics.  */
   bfd_boolean assigning_to_dot;
+
+  /* Set if the current expression used "dot", SEGMENT_START or
+     ORIGIN, but not ABSOLUTE or combined symbols in a way that forces
+     an absolute result.  Used in tracking symbols assigned from dot
+     outside of output section statements, in order to later convert
+     them from absolute.  */
+  bfd_boolean rel_from_abs;
+
   /* If evaluating an assignment, the destination.  Cleared if an
      etree_name NAME matches this, to signal a self-assignment.
      Note that an etree_name DEFINED does not clear this field, nor
@@ -222,6 +230,7 @@ fill_type *exp_get_fill
 bfd_vma exp_get_abs_int
   (etree_type *, int, char *);
 void ldexp_init (void);
+void ldexp_finalize_syms (void);
 void ldexp_finish (void);
 
 #endif