PR26907, segment contains empty SHT_NOBITS section

[Alan Modra]

Section ordering is important for _bfd_elf_map_sections_to_segments
and assign_file_positions_for_load_sections, which are only prepared
to handle sections in increasing LMA order.  When zero size sections
are involved it is possible to have multiple sections at the same LMA.
In that case the zero size sections must sort before any non-zero size
sections regardless of their types.

bfd/
	PR 26907
	* elf.c (elf_sort_sections): Don't sort zero size !load sections
	after load sections.
ld/
	* testsuite/ld-elf/pr26907.ld,
	* testsuite/ld-elf/pr26907.s,
	* testsuite/ld-elf/pr26907.d: New test.

diff --git a/bfd/elf.c b/bfd/elf.c
index 28621da915..419c5f4420 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -5257,7 +5257,8 @@ elf_sort_sections (const void *arg1, const void *arg2)
 
   /* Put !SEC_LOAD sections after SEC_LOAD ones.  */
 
-#define TOEND(x) (((x)->flags & (SEC_LOAD | SEC_THREAD_LOCAL)) == 0)
+#define TOEND(x) (((x)->flags & (SEC_LOAD | SEC_THREAD_LOCAL)) == 0 \
+		  && (x)->size != 0)
 
   if (TOEND (sec1))
     {
diff --git a/ld/testsuite/ld-elf/pr26907.d b/ld/testsuite/ld-elf/pr26907.d
new file mode 100644
index 0000000000..1efb8cc34b
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26907.d
@@ -0,0 +1,9 @@
+#ld: -T pr26907.ld
+#readelf: -lW
+#xfail: dlx-*-* ft32-*-* h8300-*-* ip2k-*-* m32r*-*-elf* m32r*-*-rtems*
+#xfail: moxie-*-* msp430-*-* mt-*-* pru*-*-* visium-*-*
+
+#failif
+#...
+ +LOAD +0x[0-9a-f]+ 0x[0-9a-f]+ 0x[0-9a-f]+ 0x0+ 0x0+ .*
+#...
diff --git a/ld/testsuite/ld-elf/pr26907.ld b/ld/testsuite/ld-elf/pr26907.ld
new file mode 100644
index 0000000000..2cce1ee09c
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26907.ld
@@ -0,0 +1,7 @@
+ENTRY (_start)
+SECTIONS
+{
+  .text : { *(.text) }
+  .bss : { . = .; *(.bss) }
+  .data : { *(.data) }
+}
diff --git a/ld/testsuite/ld-elf/pr26907.s b/ld/testsuite/ld-elf/pr26907.s
new file mode 100644
index 0000000000..13b3a54073
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr26907.s
@@ -0,0 +1,9 @@
+ .text
+ .global _start
+_start:
+ .quad 0
+
+ .data
+ .quad 0
+
+ .section .bss,"aw",%nobits

-- 
Alan Modra
Australia Development Lab, IBM