Support NEXT_SECTION in ALIGNOF and SIZEOF

This patch is aimed at making __bss_start properly aligned with the
first of any bss-style sections following.  Most of the work here
involves keeping track of the last output section seen when processing
the linker script.

You can almost align __bss_start properly by using
${RELOCATING+. = ALIGN(${DATA_SDATA-${NO_SMALL_DATA-ALIGNOF(.${SBSS_NAME}) != 0 ? ALIGNOF(.${SBSS_NAME}) : }}${BSS_PLT+ALIGNOF(.plt) != 0 ? ALIGNOF(.plt) : }ALIGNOF(.${BSS_NAME}));}
and changing every place that defines NO_SMALL_DATA to use " ", but
having two .plt sections (marked SPECIAL) on some backends foils that
idea.  The problem is that you only want to pick up the following
.plt, not the one preceeding __bss_start in the data segment if the
backend decides that is the proper .plt section.

Perhaps that could be fixed too, but I decided instead to extend the
linker script a little.  THIS_SECTION and PREV_SECTION could easily be
added too.

	* ld.texi (ALIGNOF, SIZEOF): Update and mention NEXT_SECTION.
	* ldexp.c (output_section_find): New function.
	(fold_name <ALIGNOF, SIZEOF>): Use output_section_find.
	(exp_fold_tree): Add os parameter.  Adjust all calls.
	(exp_fold_tree_no_dot, exp_get_vma, exp_get_power): Likewise.
	* ldexp.h (struct ldexp_control): Add last_os.
	(exp_fold_tree, exp_fold_tree_no_dot): Update prototypes.
	(exp_get_vma, exp_get_power): Likewise.
	* ldlang.c: Pass last output section to expression folder
	calls throughout file.
	(open_input_bfds): Add os parameter to track last os seen.
	(lang_size_sections_1): Rename output_section_statement param
	to current_os.  Track last os.
	(lang_do_assignments_1): Track last os.
	* scripttempl/arclinux.sc: Align to ALIGNOF NEXT_SECTION
	before defining __bss_start.
	* scripttempl/elf.sc: Likewise.
	* scripttempl/elf64bpf.sc: Likewise.
	* scripttempl/elf64hppa.sc: Likewise.
	* scripttempl/elf_chaos.sc: Likewise.
	* scripttempl/elfarc.sc: Likewise.
	* scripttempl/elfd10v.sc: Likewise.
	* scripttempl/elfxtensa.sc: Likewise.
	* scripttempl/epiphany_4x4.sc: Likewise.
	* scripttempl/iq2000.sc: Likewise.
	* scripttempl/mep.sc: Likewise.
	* scripttempl/nds32elf.sc: Likewise.
	* scripttempl/xstormy16.sc: Likewise.
	* testsuite/ld-x86-64/pe-x86-64-5.od: Update expected __bss_start.
	* testsuite/ld-x86-64/pe-x86-64-5.rd: Likewise.

1 files changed, 15 insertions, 5 deletions

diff --git a/ld/ldexp.h b/ld/ldexp.h
index 70908c1..7c30275 100644
--- a/ld/ldexp.h
+++ b/ld/ldexp.h
@@ -133,6 +133,8 @@ enum relro_enum {
   exp_seg_relro_end,
 };
 
+struct lang_output_section_statement_struct;
+
 typedef struct {
   enum phase_enum phase;
 
@@ -176,10 +178,17 @@ struct ldexp_control {
   etree_value_type result;
   bfd_vma dot;
 
-  /* Current dot and section passed to ldexp folder.  */
+  /* Current dot and section passed to ldexp folder.  SECTION will be
+     bfd_abs_section for expressions outside of an output section
+     statement.  */
   bfd_vma *dotp;
   asection *section;
 
+  /* Last output section statement.  For expressions within an output
+     section statement, this will be the current output section
+     statement being processed.  */
+  struct lang_output_section_statement_struct *last_os;
+
   /* State machine and results for DATASEG.  */
   seg_align_type dataseg;
 };
@@ -211,9 +220,10 @@ etree_type *exp_bigintop
 etree_type *exp_relop
   (asection *, bfd_vma);
 void exp_fold_tree
-  (etree_type *, asection *, bfd_vma *);
+  (etree_type *, struct lang_output_section_statement_struct *,
+   asection *, bfd_vma *);
 void exp_fold_tree_no_dot
-  (etree_type *);
+  (etree_type *, struct lang_output_section_statement_struct *);
 etree_type *exp_binop
   (int, etree_type *, etree_type *);
 etree_type *exp_trinop
@@ -233,9 +243,9 @@ etree_type *exp_assert
 void exp_print_tree
   (etree_type *);
 bfd_vma exp_get_vma
-  (etree_type *, bfd_vma, char *);
+  (etree_type *, struct lang_output_section_statement_struct *, bfd_vma, char *);
 int exp_get_power
-  (etree_type *, char *);
+  (etree_type *, struct lang_output_section_statement_struct *, char *);
 fill_type *exp_get_fill
   (etree_type *, fill_type *, char *);
 bfd_vma exp_get_abs_int