Delay evaluation of alignment expressions in output sections

git commit 702d16713 broke expressions using CONSTANT(COMMONPAGESIZE)
in ALIGN or SUBALIGN of output section statements, because these
optional fields were evaluated at script parse time and the patch in
question delayed setting of config.commonpagesize.  The right thing to
do is keep the tree representation of those fields for later
evaluation.

	PR 23571
	* ldlang.h (section_alignment): Make it an expression tree.
	(subsection_alignment): Likewise.
	* ldlang.c (topower): Delete.
	(output_section_statement_newfunc): Adjust initialization.
	(init_os): Evaluate section_alignment.
	(lang_size_sections_1): Likewise.
	(size_input_section): Evaluate subsection_alignment.
	(lang_enter_output_section_statement): Don't evaluate here.
	(lang_new_phdr): Use exp_get_vma rather than exp_get_value_int.
	* ldexp.h (exp_get_value_int): Delete.
	(exp_get_power): Declare.
	* ldexp.c (exp_get_value_int): Delete.
	(exp_get_power): New function.
	* emultempl/pe.em (place_orphan): Build expression for section
	alignment.
	* emultempl/pep.em (place_orphan): Likewise.
	* testsuite/ld-scripts/pr23571.d,
	* testsuite/ld-scripts/pr23571.t: New test.
	* testsuite/ld-scripts/align.exp: Run it.

1 files changed, 18 insertions, 2 deletions

diff --git a/ld/ldexp.c b/ld/ldexp.c
index 4ca812e..e123f0e 100644
--- a/ld/ldexp.c
+++ b/ld/ldexp.c
@@ -1523,10 +1523,26 @@ exp_get_vma (etree_type *tree, bfd_vma def, char *name)
   return def;
 }
 
+/* Return the smallest non-negative integer such that two raised to
+   that power is at least as large as the vma evaluated at TREE, if
+   TREE is a non-NULL expression that can be resolved.  If TREE is
+   NULL or cannot be resolved, return -1.  */
+
 int
-exp_get_value_int (etree_type *tree, int def, char *name)
+exp_get_power (etree_type *tree, char *name)
 {
-  return exp_get_vma (tree, def, name);
+  bfd_vma x = exp_get_vma (tree, -1, name);
+  bfd_vma p2;
+  int n;
+
+  if (x == (bfd_vma) -1)
+    return -1;
+
+  for (n = 0, p2 = 1; p2 < x; ++n, p2 <<= 1)
+    if (p2 == 0)
+      break;
+
+  return n;
 }
 
 fill_type *