From bba037e0aef1f3b17cc6cf6fd041ed6110cc375a Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Thu, 22 Oct 2015 12:17:43 -0700
Subject: [PATCH] Always keep sections marked with SEC_KEEP

SEC_KEEP check in elf_gc_sweep was missing in commit:

commit bde6f3eb6dff94cea1d471e15c6154d55d49820f
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Jan 8 01:43:23 2010 +0000

    Set SEC_KEEP on section XXX for undefined __start_XXX/__stop_XXX

    bfd/

    2010-01-07  H.J. Lu  <hongjiu.lu@intel.com>

      PR ld/11133
      * elflink.c (_bfd_elf_gc_mark_hook): Check section XXX for
      undefined __start_XXX/__stop_XXX in all input files and set
      SEC_KEEP.

This patch adds SEC_KEEP check to elf_gc_sweep.

bfd/

	PR ld/19161
	* elflink.c (elf_gc_sweep): Always keep sections marked with
	SEC_KEEP.

ld/testsuite/

	PR ld/19161
	* ld-gc/gc.exp: Run pr19161 test.
	* ld-gc/pr19161-1.c: New file.
	* ld-gc/pr19161-2.c: Likewise.
	* ld-gc/pr19161.d: Likewise.
---
 bfd/ChangeLog                  |  6 ++++++
 bfd/elflink.c                  |  3 ++-
 ld/testsuite/ChangeLog         |  8 ++++++++
 ld/testsuite/ld-gc/gc.exp      |  6 ++++++
 ld/testsuite/ld-gc/pr19161-1.c |  7 +++++++
 ld/testsuite/ld-gc/pr19161-2.c | 19 +++++++++++++++++++
 ld/testsuite/ld-gc/pr19161.d   |  9 +++++++++
 7 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 ld/testsuite/ld-gc/pr19161-1.c
 create mode 100644 ld/testsuite/ld-gc/pr19161-2.c
 create mode 100644 ld/testsuite/ld-gc/pr19161.d

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index e647a2b8cc..60b79ed594 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2015-10-22  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/19161
+	* elflink.c (elf_gc_sweep): Always keep sections marked with
+	SEC_KEEP.
+
 2015-10-22  Hans-Peter Nilsson  <hp@bitrange.com>
 
 	* mmo.c (struct mmo_data_struct): New members
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 73fe469d36..06df821956 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -12449,7 +12449,8 @@ elf_gc_sweep (bfd *abfd, struct bfd_link_info *info)
 	      o->gc_mark = first->gc_mark;
 	    }
 
-	  if (o->gc_mark)
+	  /* Always keep sections marked with SEC_KEEP.  */
+	  if (o->gc_mark || (o->flags & SEC_KEEP))
 	    continue;
 
 	  /* Skip sweeping sections already excluded.  */
diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index a2062471a3..12c4dce318 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2015-10-22  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/19161
+	* ld-gc/gc.exp: Run pr19161 test.
+	* ld-gc/pr19161-1.c: New file.
+	* ld-gc/pr19161-2.c: Likewise.
+	* ld-gc/pr19161.d: Likewise.
+
 2015-10-22  Hans-Peter Nilsson  <hp@bitrange.com>
 
 	* ld-scripts/script.exp (extract_symbol_test): Allow nm output of
diff --git a/ld/testsuite/ld-gc/gc.exp b/ld/testsuite/ld-gc/gc.exp
index b2a3450846..f7438d45d3 100644
--- a/ld/testsuite/ld-gc/gc.exp
+++ b/ld/testsuite/ld-gc/gc.exp
@@ -139,3 +139,9 @@ if { [is_remote host] || [which $CC] != 0 } {
     ld_compile "$CC $CFLAGS $cflags" $srcdir/$subdir/pr14265.c tmpdir/pr14265.o
     run_dump_test "pr14265"
 }
+
+if { [is_remote host] || [which $CC] != 0 } {
+    ld_compile "$CC $CFLAGS $cflags -O0" $srcdir/$subdir/pr19161-1.c tmpdir/pr19161-1.o
+    ld_compile "$CC $CFLAGS $cflags -O0" $srcdir/$subdir/pr19161-2.c tmpdir/pr19161-2.o
+    run_dump_test "pr19161"
+}
diff --git a/ld/testsuite/ld-gc/pr19161-1.c b/ld/testsuite/ld-gc/pr19161-1.c
new file mode 100644
index 0000000000..519948e9b4
--- /dev/null
+++ b/ld/testsuite/ld-gc/pr19161-1.c
@@ -0,0 +1,7 @@
+int (*p)(void);
+
+int
+main ()
+{
+  return p () != 0x1234;
+}
diff --git a/ld/testsuite/ld-gc/pr19161-2.c b/ld/testsuite/ld-gc/pr19161-2.c
new file mode 100644
index 0000000000..b51f31a542
--- /dev/null
+++ b/ld/testsuite/ld-gc/pr19161-2.c
@@ -0,0 +1,19 @@
+int __attribute__((section("my_section"))) a[2] = {0x1234, 0x5678};
+
+extern int __start_my_section;
+
+extern int (*p)(void);
+
+int
+dump()
+{
+   int* ap = &__start_my_section;
+   return ap[0];
+}
+
+void 
+__attribute__((constructor))
+foo()
+{
+  p = dump;
+}
diff --git a/ld/testsuite/ld-gc/pr19161.d b/ld/testsuite/ld-gc/pr19161.d
new file mode 100644
index 0000000000..64b17e089e
--- /dev/null
+++ b/ld/testsuite/ld-gc/pr19161.d
@@ -0,0 +1,9 @@
+#name: --gc-sections with __start_SECTIONNAME
+#source: dummy.s
+#ld: --gc-sections -e main tmpdir/pr19161-1.o tmpdir/pr19161-2.o
+#nm: --format=bsd
+#xfail: sh64*-*-* iq2000-*-* lm32-*-* epiphany-*-* mips64vr-*-* frv-*-* m32c-*-* rl78-*-* rx-*-* sh-*-* powerpc*-*-eabivle msp430-*-*
+
+#...
+0*[1-9a-f]+[0-9a-f]*[ 	](D)[ 	]_*__start_my_section
+#...