Add cantunwind when unwind info does not match start of section.

bfd     * elf32-arm.c (elf32_arm_fix_exidx_coverage): Insert cantunwind when
        address in first unwind entry does not match start of section.

tests   * ld-arm/arm-elf.exp: New test.
        * ld-arm/unwind-mix.d: New file.
        * ld-arm/unwind-mix1.s: New file.
        * ld-arm/unwind-mix2.s: New file.

bfd/ChangeLog

@@ -1,3 +1,9 @@
+2016-01-12  Yury Usishchev  <y.usishchev@samsung.com>
+
+	* elf32-arm.c (elf32_arm_fix_exidx_coverage): Insert cantunwind
+	when address in first unwind entry does not match start of
+	section.
+
 2016-01-08  Richard Sandiford  <richard.sandiford@arm.com>
 	    Jiong Wang  <jiong.wang@arm.com>
 

bfd/elf32-arm.c

@@ -11740,6 +11740,18 @@ elf32_arm_fix_exidx_coverage (asection **text_section_order,
 	/* An error?  */
 	continue;
 
+      if (last_unwind_type > 0)
+	{
+	  unsigned int first_word = bfd_get_32 (ibfd, contents);
+	  /* Add cantunwind if first unwind item does not match section
+	     start.  */
+	  if (first_word != sec->vma)
+	    {
+	      insert_cantunwind_after (last_text_sec, last_exidx_sec);
+	      last_unwind_type = 0;
+	    }
+	}
+
       for (j = 0; j < hdr->sh_size; j += 8)
 	{
 	  unsigned int second_word = bfd_get_32 (ibfd, contents + j + 4);

ld/ChangeLog

@@ -1,3 +1,10 @@
+2016-01-12  Yury Usishchev  <y.usishchev@samsung.com>
+
+	* testsuite/ld-arm/arm-elf.exp: New test.
+	* testsuite/ld-arm/unwind-mix.d: New file.
+	* testsuite/ld-arm/unwind-mix1.s: New file.
+	* testsuite/ld-arm/unwind-mix2.s: New file.
+
 2016-01-08  Jiong Wang  <jiong.wang@arm.com>
 
 	PR ld/19368

ld/testsuite/ld-arm/arm-elf.exp

@@ -964,5 +964,8 @@ set arm_unwind_tests {
     {"unwind-rel" "-r -Tarm.ld" "" "" {unwind-rel1.s unwind-rel2.s unwind-rel3.s}
      {{readelf -ur unwind-rel.d}}
      "unwind-rel"}
+    {"unwind-mix" "-Tarm.ld" "" "" {unwind-mix1.s unwind-mix2.s}
+     {{readelf -u unwind-mix.d}}
+     "unwind-mix"}
 }
 run_ld_link_tests $arm_unwind_tests

ld/testsuite/ld-arm/unwind-mix.d

@@ -0,0 +1,20 @@
+
+Unwind table index '\.ARM\.exidx' at offset .* contains 4 entries:
+
+0x8004 <_start>: @0x8010
+  Compact model index: 1
+  0xc9 0x40 pop {D4}
+  0xc9 0x00 pop {D0}
+  0xa8      pop {r4, r14}
+  0xb0      finish
+
+0x8008 <__aeabi_unwind_cpp_pr1>: 0x1 \[cantunwind\]
+
+0x800c <end>: 0x80a8b0b0
+  Compact model index: 0
+  0xa8      pop {r4, r14}
+  0xb0      finish
+  0xb0      finish
+
+0x8010 <end\+0x4>: 0x1 \[cantunwind\]
+

ld/testsuite/ld-arm/unwind-mix1.s

@@ -0,0 +1,16 @@
+	.syntax unified
+	.text
+	.global __aeabi_unwind_cpp_pr0
+	.type __aeabi_unwind_cpp_pr0, %function
+__aeabi_unwind_cpp_pr0:
+	bx lr
+
+	.global _start
+	.type _start, %function
+_start:
+	.fnstart
+	.save {r4, lr}
+	.vsave {d0}
+	.vsave {d4}
+	bx lr
+	.fnend

ld/testsuite/ld-arm/unwind-mix2.s

@@ -0,0 +1,15 @@
+	.syntax unified
+	.text
+	.global __aeabi_unwind_cpp_pr1
+	.type __aeabi_unwind_cpp_pr1, %function
+__aeabi_unwind_cpp_pr1:
+	bx lr
+
+	.global end
+	.type end, %function
+end:
+	.fnstart
+	.save {r4, lr}
+	bx lr
+	.fnend
+