Re: [RFC PATCH] avoid intermingling executable and nonexecutable sections in a segment

[Roland McGrath <mcgrathr at google dot com>]

Here's what I've committed to trunk.
OK for 2.23 branch too?


Thanks,
Roland


ld/
2012-11-21  Roland McGrath  <mcgrathr@google.com>

	* ld.h (ld_config_type): New flag member separate_code.
	* emultempl/elf32.em
	(gld${EMULATION_NAME}_before_parse): Set it based on $SEPARATE_CODE.
	* ldlang.c (ldlang_override_segment_assignment): If it's set, then
	always return TRUE when SEC_CODE differs between the sections.

--- a/ld/emultempl/elf32.em
+++ b/ld/emultempl/elf32.em
@@ -104,6 +104,7 @@ gld${EMULATION_NAME}_before_parse (void)
   ldfile_set_output_arch ("${OUTPUT_ARCH}", bfd_arch_`echo ${ARCH} |
sed -e 's/:.*//'`);
   input_flags.dynamic = ${DYNAMIC_LINK-TRUE};
   config.has_shared = `if test -n "$GENERATE_SHLIB_SCRIPT" ; then
echo TRUE ; else echo FALSE ; fi`;
+  config.separate_code = `if test "x${SEPARATE_CODE}" = xyes ; then
echo TRUE ; else echo FALSE ; fi`;
 }

 EOF
--- a/ld/ld.h
+++ b/ld/ld.h
@@ -274,6 +274,9 @@ typedef struct {
      numbers everywhere.  */
   bfd_boolean sane_expr;

+  /* If set, code and non-code sections should never be in one segment.  */
+  bfd_boolean separate_code;
+
   /* The rpath separation character.  Usually ':'.  */
   char rpath_separator;

--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -5361,6 +5361,12 @@ ldlang_override_segment_assignment (struct
bfd_link_info * info ATTRIBUTE_UNUSED
   if (current_section == NULL || previous_section == NULL)
     return new_segment;

+  /* If this flag is set, the target never wants code and non-code
+     sections comingled in the same segment.  */
+  if (config.separate_code
+      && ((current_section->flags ^ previous_section->flags) & SEC_CODE))
+    return TRUE;
+
   /* Find the memory regions associated with the two sections.
      We call lang_output_section_find() here rather than scanning the list
      of output sections looking for a matching section pointer because if