Re: Consistency check for merge sections

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Wed, Sep 30, 2015 at 04:11:01PM +0930, Alan Modra wrote:
> We can't allow sections to be merged and sized by the ELF linker
> backend and then later be output by the generic linker backend.  The
> generic linker backend doesn't understand merge sections.
> 
> 	PR ld/19013
> 	* elflink.c (_bfd_elf_merge_sections): Only merge input bfds that
> 	will be handled by elf_link_input_bfd.  Rename abfd param to obfd.
> 

This isn't sufficient.  When we check consistency for merge ELF sections,
we should not only check EI_CLASS, but also compatible e_machine.  I
checked in this to check e_machine.

H.J.
---
bfd/

	PR ld/19013
	* elflink.c (_bfd_elf_merge_sections): Only merge input bfds
	that have the compatible ELF machine code with the output bfd.

ld/testsuite/

	PR ld/19013
	* ld-x86-64/pr19013-nacl.d: New file.
	* ld-x86-64/pr19013-x32.d: Likewise.
	* ld-x86-64/pr19013.d: Likewise.
	* ld-x86-64/pr19013.s: Likewise.
	* ld-x86-64/x86-64.exp: Run PR ld/19013 tests.
---
 bfd/ChangeLog                         |  6 ++++++
 bfd/elflink.c                         | 12 ++++++++++--
 ld/testsuite/ChangeLog                |  9 +++++++++
 ld/testsuite/ld-x86-64/pr19013-nacl.d |  9 +++++++++
 ld/testsuite/ld-x86-64/pr19013-x32.d  |  9 +++++++++
 ld/testsuite/ld-x86-64/pr19013.d      |  8 ++++++++
 ld/testsuite/ld-x86-64/pr19013.s      |  5 +++++
 ld/testsuite/ld-x86-64/x86-64.exp     |  3 +++
 8 files changed, 59 insertions(+), 2 deletions(-)
 create mode 100644 ld/testsuite/ld-x86-64/pr19013-nacl.d
 create mode 100644 ld/testsuite/ld-x86-64/pr19013-x32.d
 create mode 100644 ld/testsuite/ld-x86-64/pr19013.d
 create mode 100644 ld/testsuite/ld-x86-64/pr19013.s

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index f4ca2ec..a218d44 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2015-09-30  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/19013
+	* elflink.c (_bfd_elf_merge_sections): Only merge input bfds
+	that have the compatible ELF machine code with the output bfd.
+
 2015-09-30  Alan Modra  <amodra@gmail.com>
 
 	PR ld/19013
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 90af6cf..70c231b 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -6818,15 +6818,23 @@ _bfd_elf_merge_sections (bfd *obfd, struct bfd_link_info *info)
 {
   bfd *ibfd;
   asection *sec;
+  const struct elf_backend_data *bed;
 
   if (!is_elf_hash_table (info->hash))
     return FALSE;
 
+  bed = get_elf_backend_data (obfd);
   for (ibfd = info->input_bfds; ibfd != NULL; ibfd = ibfd->link.next)
     if ((ibfd->flags & DYNAMIC) == 0
 	&& bfd_get_flavour (ibfd) == bfd_target_elf_flavour
-	&& (elf_elfheader (ibfd)->e_ident[EI_CLASS]
-	    == get_elf_backend_data (obfd)->s->elfclass))
+	&& (elf_elfheader (ibfd)->e_ident[EI_CLASS] == bed->s->elfclass)
+	&& (bed->elf_machine_code == elf_elfheader (ibfd)->e_machine
+	    || (bed->elf_machine_alt1 != 0
+		&& (bed->elf_machine_alt1
+		    == elf_elfheader (ibfd)->e_machine))
+	    || (bed->elf_machine_alt2 != 0
+		&& (bed->elf_machine_alt2
+		    == elf_elfheader (ibfd)->e_machine))))
       for (sec = ibfd->sections; sec != NULL; sec = sec->next)
 	if ((sec->flags & SEC_MERGE) != 0
 	    && !bfd_is_abs_section (sec->output_section))
diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index 40eb358..7f1b7ac 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,3 +1,12 @@
+2015-09-30  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/19013
+	* ld-x86-64/pr19013-nacl.d: New file.
+	* ld-x86-64/pr19013-x32.d: Likewise.
+	* ld-x86-64/pr19013.d: Likewise.
+	* ld-x86-64/pr19013.s: Likewise.
+	* ld-x86-64/x86-64.exp: Run PR ld/19013 tests.
+
 2015-09-29  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR binutils/19005
diff --git a/ld/testsuite/ld-x86-64/pr19013-nacl.d b/ld/testsuite/ld-x86-64/pr19013-nacl.d
new file mode 100644
index 0000000..7294ed2
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr19013-nacl.d
@@ -0,0 +1,9 @@
+#source: pr19013.s
+#as: --x32
+#ld: --oformat elf32-i386-nacl
+#objdump: -s -j .rodata
+#target: x86_64-*-nacl*
+
+#...
+ [0-9a-f]+ 00000203 00414243 4400 +.....ABCD. +
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr19013-x32.d b/ld/testsuite/ld-x86-64/pr19013-x32.d
new file mode 100644
index 0000000..fb70966
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr19013-x32.d
@@ -0,0 +1,9 @@
+#source: pr19013.s
+#as: --x32
+#ld: --oformat elf32-i386 -m elf32_x86_64
+#objdump: -s -j .rodata
+#notarget: x86_64-*-nacl*
+
+#...
+ [0-9a-f]+ 00000203 00414243 4400 +.....ABCD. +
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr19013.d b/ld/testsuite/ld-x86-64/pr19013.d
new file mode 100644
index 0000000..9b1473a
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr19013.d
@@ -0,0 +1,8 @@
+#as: --64
+#ld: --oformat elf32-i386
+#objdump: -s -j .rodata
+#notarget: x86_64-*-nacl*
+
+#...
+ [0-9a-f]+ 00000203 00414243 4400 +.....ABCD. +
+#pass
diff --git a/ld/testsuite/ld-x86-64/pr19013.s b/ld/testsuite/ld-x86-64/pr19013.s
new file mode 100644
index 0000000..db95ecb
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr19013.s
@@ -0,0 +1,5 @@
+	.section    .rodata.str1.1,"aMS",@progbits,1
+	.globl	_start
+_start:
+	.byte 0x0, 0x0, 0x2, 0x3, 0x0
+	.string "ABCD"
diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
index 6320999..5de67ca 100644
--- a/ld/testsuite/ld-x86-64/x86-64.exp
+++ b/ld/testsuite/ld-x86-64/x86-64.exp
@@ -327,6 +327,9 @@ run_dump_test "pr18160"
 run_dump_test "pr18176"
 run_dump_test "pr18801"
 run_dump_test "pr18815"
+run_dump_test "pr19013"
+run_dump_test "pr19013-x32"
+run_dump_test "pr19013-nacl"
 
 # Add $PLT_CFLAGS if PLT is expected.
 global PLT_CFLAGS
-- 
2.4.3