Allow note sections to be discarded when they are linked to another discarded secction.

PR 26681
bfd	* elflink.c (bfd_elf_gc_sections): Do not arbitrarily keep note
	sections which are linked to another section.

ld	* testsuite/ld-elf/pr26681.s: New test.
	* testsuite/ld-elf/pr26681.d: New test driver.
	* testsuite/ld-elf/pr26681.l: New test output.

bfd/ChangeLog

@@ -1,3 +1,9 @@
+2020-10-02  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR 26681
+	* elflink.c (bfd_elf_gc_sections): Do not arbitrarily keep note
+	sections which are linked to another section.
+
 2020-09-28  Przemyslaw Wirkus  <przemyslaw.wirkus@arm.com>
 
 	* cpu-arm.c: (processors) Add Cortex-X1.

bfd/elflink.c

@@ -14102,7 +14102,8 @@ bfd_elf_gc_sections (bfd *abfd, struct bfd_link_info *info)
 			|| (elf_section_data (o)->this_hdr.sh_type
 			    == SHT_FINI_ARRAY)))
 		|| (elf_section_data (o)->this_hdr.sh_type == SHT_NOTE
-		    && elf_next_in_group (o) == NULL )))
+		    && elf_next_in_group (o) == NULL
+		    && elf_linked_to_section (o) == NULL)))
 	  {
 	    if (!_bfd_elf_gc_mark (info, o, gc_mark_hook))
 	      return FALSE;

ld/ChangeLog

@@ -1,3 +1,10 @@
+2020-10-01  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR 26681
+	* testsuite/ld-elf/pr26681.s: New test.
+	* testsuite/ld-elf/pr26681.d: New test driver.
+	* testsuite/ld-elf/pr26681.l: New test output.
+
 2020-09-30  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR ld/26675

ld/testsuite/ld-elf/pr26681.d

@@ -0,0 +1,3 @@
+#ld: --gc-sections --print-gc-sections -e _start
+#warning_output: pr26681.l
+#target: [check_gc_sections_available]

ld/testsuite/ld-elf/pr26681.l

@@ -0,0 +1,5 @@
+#...
+.*: removing unused section '\.unused1' in file 'tmpdir/.*\.o'
+#...
+.*: removing unused section '\.gnu.note1' in file 'tmpdir/.*\.o'
+#...

ld/testsuite/ld-elf/pr26681.s

@@ -0,0 +1,10 @@
+    	.text
+	.globl _start
+_start:
+	.nop
+
+	.section .unused1, "ax", %progbits
+	.nop
+
+	.section .gnu.note1, "o", %note, .unused1
+	.word 2