Define DIFF_EXPR_OK for avr target to allow PC relative difference relocation.

When generating relocation (tc_gen_reloc) 32 bit relocation fixup
is changed to new 32 bit PC relative relocation if the fixup has pc-relative
flag set.

bfd/ChangeLog

2015-07-06  Pitchumani Sivanupandi <pitchumani.s@atmel.com>

    * elf32-avr.c: Add 32 bit PC relative relocation for AVR target.

gas/ChangeLog

2015-07-06  Pitchumani Sivanupandi <pitchumani.s@atmel.com>

    * config/tc-avr.c (tc_gen_reloc): Change 32 bit relocation to
    32 bit PC relative and update offset if the fixup is pc-relative.
    * config/tc-avr.h (DIFF_EXPR_OK): Define to enable PC relative diff
    relocs.

gas/testsuite/ChangeLog

2015-07-06  Pitchumani Sivanupandi <pitchumani.s@atmel.com>

    * gas/avr/pc-relative-reloc.d: New test for 32 bit pc relative reloc.
    * gas/avr/per-function-debugline.s: New test source.

include/ChangeLog

2015-07-06  Pitchumani Sivanupandi <pitchumani.s@atmel.com>

    * elf/avr.h: Add new 32 bit PC relative relocation.

ld/testsuite/ChangeLog

2015-07-06  Pitchumani Sivanupandi <pitchumani.s@atmel.com>

    * ld-avr/gc-section-debugline.d: New test.
    * ld-avr/per-function-debugline.s: Source for new test.

6 files changed, 84 insertions, 2 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index f9d4892..4439de5 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,10 @@
+2015-07-08  Pitchumani Sivanupandi <pitchumani.s@atmel.com>
+
+	* config/tc-avr.c (tc_gen_reloc): Change 32 bit relocation to
+	32 bit PC relative and update offset if the fixup is pc-relative.
+	* config/tc-avr.h (DIFF_EXPR_OK): Define to enable PC relative diff
+	relocs.
+
 2015-07-03  Alan Modra  <amodra@gmail.com>
 
 	* config/tc-ppc.c (md_show_usage): Add -m821, -m850, -m860.
diff --git a/gas/config/tc-avr.c b/gas/config/tc-avr.c
index 5c8982c..c69a91c 100644
--- a/gas/config/tc-avr.c
+++ b/gas/config/tc-avr.c
@@ -1618,6 +1618,7 @@ tc_gen_reloc (asection *seg ATTRIBUTE_UNUSED,
 	      fixS *fixp)
 {
   arelent *reloc;
+  bfd_reloc_code_real_type code = fixp->fx_r_type;
 
   if (fixp->fx_subsy != NULL)
     {
@@ -1631,7 +1632,21 @@ tc_gen_reloc (asection *seg ATTRIBUTE_UNUSED,
   *reloc->sym_ptr_ptr = symbol_get_bfdsym (fixp->fx_addsy);
 
   reloc->address = fixp->fx_frag->fr_address + fixp->fx_where;
-  reloc->howto = bfd_reloc_type_lookup (stdoutput, fixp->fx_r_type);
+
+  if ((fixp->fx_r_type == BFD_RELOC_32) && (fixp->fx_pcrel))
+    {
+      if (seg->use_rela_p)
+        fixp->fx_offset -= md_pcrel_from_section (fixp, seg);
+      else
+        fixp->fx_offset = reloc->address;
+
+      code = BFD_RELOC_32_PCREL;
+    }
+
+  reloc->addend = fixp->fx_offset;
+
+  reloc->howto = bfd_reloc_type_lookup (stdoutput, code);
+
   if (reloc->howto == (reloc_howto_type *) NULL)
     {
       as_bad_where (fixp->fx_file, fixp->fx_line,
@@ -1644,7 +1659,6 @@ tc_gen_reloc (asection *seg ATTRIBUTE_UNUSED,
       || fixp->fx_r_type == BFD_RELOC_VTABLE_ENTRY)
     reloc->address = fixp->fx_offset;
 
-  reloc->addend = fixp->fx_offset;
 
   return reloc;
 }
diff --git a/gas/config/tc-avr.h b/gas/config/tc-avr.h
index 21471c8..5501ef0 100644
--- a/gas/config/tc-avr.h
+++ b/gas/config/tc-avr.h
@@ -45,6 +45,8 @@
    nonstandard escape sequences in a string.  */
 #define ONLY_STANDARD_ESCAPES
 
+#define DIFF_EXPR_OK    /* .-foo gets turned into PC relative relocs */
+
 /* GAS will call this function for any expression that can not be
    recognized.  When the function is called, `input_line_pointer'
    will point to the start of the expression.  */
diff --git a/gas/testsuite/ChangeLog b/gas/testsuite/ChangeLog
index a045c85..aecbef6 100644
--- a/gas/testsuite/ChangeLog
+++ b/gas/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2015-07-08  Pitchumani Sivanupandi <pitchumani.s@atmel.com>
+
+	* gas/avr/pc-relative-reloc.d: New test for 32 bit pc relative reloc.
+	* gas/avr/per-function-debugline.s: New test source.
+
 2015-07-03  Alan Modra  <alan@squeak.grove.modra.org>
 
 	* gas/ppc/titan.d: Correct mfmcsrr0 disassembly.
diff --git a/gas/testsuite/gas/avr/pc-relative-reloc.d b/gas/testsuite/gas/avr/pc-relative-reloc.d
new file mode 100644
index 0000000..cc22b0b
--- /dev/null
+++ b/gas/testsuite/gas/avr/pc-relative-reloc.d
@@ -0,0 +1,19 @@
+#name: 32 bit PC relative reloc
+#as: -mmcu=avr51 -gdwarf-sections -g
+#objdump: -r
+#source: per-function-debugline.s
+#target: avr-*-*
+
+.*:     file format elf32-avr
+
+RELOCATION RECORDS FOR \[.text.main\]:
+#...
+
+
+RELOCATION RECORDS FOR \[.debug_line\]:
+OFFSET   TYPE              VALUE 
+00000000 R_AVR_32_PCREL    .debug_line_end-0x00000004
+
+
+RELOCATION RECORDS FOR \[.debug_line.text.main\]:
+#...
diff --git a/gas/testsuite/gas/avr/per-function-debugline.s b/gas/testsuite/gas/avr/per-function-debugline.s
new file mode 100644
index 0000000..4db56e5
--- /dev/null
+++ b/gas/testsuite/gas/avr/per-function-debugline.s
@@ -0,0 +1,35 @@
+	.file	"per-function-debugline.s"
+__SP_H__ = 0x3e
+__SP_L__ = 0x3d
+__SREG__ = 0x3f
+__RAMPZ__ = 0x3b
+__tmp_reg__ = 0
+__zero_reg__ = 1
+	.comm	g,2,1
+	.section	.text.main,"ax",@progbits
+.global	main
+	.type	main, @function
+main:
+	push r28
+	push r29
+	in r28,__SP_L__
+	in r29,__SP_H__
+/* prologue: function */
+/* frame size = 0 */
+/* stack size = 2 */
+.L__stack_usage = 2
+	call foo
+	lds r24,g
+	lds r25,g+1
+	sbiw r24,1
+	sts g+1,r25
+	sts g,r24
+	lds r24,g
+	lds r25,g+1
+/* epilogue start */
+	pop r29
+	pop r28
+	ret
+	.size	main, .-main
+	.ident	"GCC: (GNU) 6.0.0 20150630 (experimental)"
+.global __do_clear_bss