[PATCH][ARC] Refurbish emitting DWARF2 for epilogue.

[Claudiu Zissulescu <Claudiu.Zissulescu@synopsys.com>]

Properly emit DWARF2 related information while expanding epilogue. Remove
the -m[no]-epilogue-cfi option as it is not needed any longer. This patch
solves the dwarf2cfi errors observed while running dejagnu tests.

Ok to commit?
Claudiu

gcc/
2015-11-27  Claudiu Zissulescu  <claziss@synopsys.com>

	* config/arc/arc.c (frame_move): Set frame related flag.
	(arc_save_restore): Emit epilogue related DWARF2 information.
	(arc_expand_epilogue): Likewise.
	* config/arc/arc.opt (mno-epilogue-cfi): Remove.
	(mepilogue-cfi): Likewise.
	* doc/invoke.texi: Remove -m[no]-epilogue-cfi documentation.
---
 gcc/config/arc/arc.c   | 87 ++++++++++++++++++++++++++++++++++++++++----------
 gcc/config/arc/arc.opt |  8 -----
 gcc/doc/invoke.texi    | 10 +-----
 3 files changed, 71 insertions(+), 34 deletions(-)

diff --git a/gcc/config/arc/arc.c b/gcc/config/arc/arc.c
index 8bb0969..5200ea5 100644
--- a/gcc/config/arc/arc.c
+++ b/gcc/config/arc/arc.c
@@ -1884,7 +1884,9 @@ frame_insn (rtx x)
 static rtx
 frame_move (rtx dst, rtx src)
 {
-  return frame_insn (gen_rtx_SET (dst, src));
+  rtx tmp = gen_rtx_SET (dst, src);
+  RTX_FRAME_RELATED_P (tmp) = 1;
+  return frame_insn (tmp);
 }
 
 /* Like frame_move, but add a REG_INC note for REG if ADDR contains an
@@ -2307,7 +2309,15 @@ arc_save_restore (rtx base_reg,
 	  if (epilogue_p == 2)
 	    sibthunk_insn = insn;
 	  else
-	    frame_insn (insn);
+	    {
+	      insn = frame_insn (insn);
+	      if (epilogue_p)
+		for (r = start_call; r <= end_call; r++)
+		  {
+		    rtx reg = gen_rtx_REG (SImode, r);
+		    add_reg_note (insn, REG_CFA_RESTORE, reg);
+		  }
+	    }
 	  offset += off;
 	}
 
@@ -2317,6 +2327,7 @@ arc_save_restore (rtx base_reg,
 	    {
 	      rtx reg = gen_rtx_REG (SImode, regno);
 	      rtx addr, mem;
+	      int cfa_adjust = *first_offset;
 
 	      if (*first_offset)
 		{
@@ -2332,7 +2343,20 @@ arc_save_restore (rtx base_reg,
 		}
 	      mem = gen_frame_mem (SImode, addr);
 	      if (epilogue_p)
-		frame_move_inc (reg, mem, base_reg, addr);
+		{
+		  rtx insn =
+		    frame_move_inc (reg, mem, base_reg, addr);
+		  add_reg_note (insn, REG_CFA_RESTORE, reg);
+		  if (cfa_adjust)
+		    {
+		      enum reg_note note = REG_CFA_ADJUST_CFA;
+		      add_reg_note (insn, note,
+				    gen_rtx_SET (stack_pointer_rtx,
+						 plus_constant (Pmode,
+								stack_pointer_rtx,
+								cfa_adjust)));
+		    }
+		}
 	      else
 		frame_move_inc (mem, reg, base_reg, addr);
 	      offset += UNITS_PER_WORD;
@@ -2341,6 +2365,10 @@ arc_save_restore (rtx base_reg,
     }/* if */
   if (sibthunk_insn)
     {
+      int start_call = frame->millicode_start_reg;
+      int end_call = frame->millicode_end_reg;
+      int r;
+
       rtx r12 = gen_rtx_REG (Pmode, 12);
 
       frame_insn (gen_rtx_SET (r12, GEN_INT (offset)));
@@ -2350,6 +2378,15 @@ arc_save_restore (rtx base_reg,
 		       gen_rtx_PLUS (Pmode, stack_pointer_rtx, r12));
       sibthunk_insn = emit_jump_insn (sibthunk_insn);
       RTX_FRAME_RELATED_P (sibthunk_insn) = 1;
+
+      /* Would be nice if we could do this earlier, when the PARALLEL
+	 is populated, but these need to be attached after the
+	 emit.  */
+      for (r = start_call; r <= end_call; r++)
+	{
+	  rtx reg = gen_rtx_REG (SImode, r);
+	  add_reg_note (sibthunk_insn, REG_CFA_RESTORE, reg);
+	}
     }
 } /* arc_save_restore */
 
@@ -2470,6 +2507,7 @@ arc_expand_epilogue (int sibcall_p)
   int can_trust_sp_p = !cfun->calls_alloca;
   int first_offset = 0;
   int millicode_p = cfun->machine->frame_info.millicode_end_reg > 0;
+  rtx insn;
 
   size_to_deallocate = size;
 
@@ -2502,11 +2540,18 @@ arc_expand_epilogue (int sibcall_p)
   /* Restore any saved registers.  */
   if (frame_pointer_needed)
     {
-	  rtx addr = gen_rtx_POST_INC (Pmode, stack_pointer_rtx);
+      insn = emit_insn (gen_blockage ());
+      add_reg_note (insn, REG_CFA_DEF_CFA,
+		    plus_constant (SImode, stack_pointer_rtx,
+				   4));
+      RTX_FRAME_RELATED_P (insn) = 1;
 
-	  frame_move_inc (frame_pointer_rtx, gen_frame_mem (Pmode, addr),
-			  stack_pointer_rtx, 0);
-	  size_to_deallocate -= UNITS_PER_WORD;
+      rtx addr = gen_rtx_POST_INC (Pmode, stack_pointer_rtx);
+
+      insn = frame_move_inc (frame_pointer_rtx, gen_frame_mem (Pmode, addr),
+			     stack_pointer_rtx, 0);
+      add_reg_note (insn, REG_CFA_RESTORE, frame_pointer_rtx);
+      size_to_deallocate -= UNITS_PER_WORD;
     }
 
   /* Load blink after the calls to thunk calls in case of optimize size.  */
@@ -2522,7 +2567,7 @@ arc_expand_epilogue (int sibcall_p)
 			    cfun->machine->frame_info.gmask,
 			    1 + sibthunk_p, &first_offset);
 	  if (sibthunk_p)
-	    goto epilogue_done;
+	    return;
     }
   /* If we are to restore registers, and first_offset would require
      a limm to be encoded in a PRE_MODIFY, yet we can add it with a
@@ -2546,6 +2591,7 @@ arc_expand_epilogue (int sibcall_p)
       rtx ra = gen_rtx_REG (Pmode, RETURN_ADDR_REGNUM);
       int ra_offs = cfun->machine->frame_info.reg_size + first_offset;
       rtx addr = plus_constant (Pmode, stack_pointer_rtx, ra_offs);
+      HOST_WIDE_INT cfa_adjust = 0;
 
       /* If the load of blink would need a LIMM, but we can add
 	 the offset quickly to sp, do the latter.  */
@@ -2571,15 +2617,29 @@ arc_expand_epilogue (int sibcall_p)
 	  && (SMALL_INT (ra_offs) || !SMALL_INT (ra_offs >> 2)))
 	{
 	  addr = gen_rtx_PRE_MODIFY (Pmode, stack_pointer_rtx, addr);
+	  cfa_adjust = ra_offs;
 	  first_offset = 0;
 	  size_to_deallocate -= cfun->machine->frame_info.reg_size;
 	}
       else if (!ra_offs && size_to_deallocate == UNITS_PER_WORD)
 	{
 	  addr = gen_rtx_POST_INC (Pmode, addr);
+	  cfa_adjust = GET_MODE_SIZE (Pmode);
 	  size_to_deallocate = 0;
 	}
-      frame_move_inc (ra, gen_frame_mem (Pmode, addr), stack_pointer_rtx, addr);
+
+      insn = frame_move_inc (ra, gen_frame_mem (Pmode, addr),
+			     stack_pointer_rtx, addr);
+      if (cfa_adjust)
+	{
+	  enum reg_note note = REG_CFA_ADJUST_CFA;
+
+	  add_reg_note (insn, note,
+			gen_rtx_SET (stack_pointer_rtx,
+				     plus_constant (SImode, stack_pointer_rtx,
+						    cfa_adjust)));
+	}
+      add_reg_note (insn, REG_CFA_RESTORE, ra);
     }
 
   if (!millicode_p)
@@ -2603,17 +2663,10 @@ arc_expand_epilogue (int sibcall_p)
 
   if (size > restored)
     frame_stack_add (size - restored);
+
   /* Emit the return instruction.  */
   if (sibcall_p == FALSE)
     emit_jump_insn (gen_simple_return ());
- epilogue_done:
-  if (!TARGET_EPILOGUE_CFI)
-    {
-      rtx_insn *insn;
-
-      for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
-	RTX_FRAME_RELATED_P (insn) = 0;
-    }
 }
 
 /* Return the offset relative to the stack pointer where the return address
diff --git a/gcc/config/arc/arc.opt b/gcc/config/arc/arc.opt
index 0c10c67..55aca14 100644
--- a/gcc/config/arc/arc.opt
+++ b/gcc/config/arc/arc.opt
@@ -340,14 +340,6 @@ mrtsc
 Target Report
 Enable 64-bit Time-Stamp Counter extension instruction.
 
-mno-epilogue-cfi
-Target Report RejectNegative InverseMask(EPILOGUE_CFI)
-Disable generation of cfi for epilogues.
-
-mepilogue-cfi
-Target RejectNegative Mask(EPILOGUE_CFI)
-Enable generation of cfi for epilogues.
-
 EB
 Target
 Pass -EB option through to linker.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 7cef176..3b00e88 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -544,7 +544,7 @@ Objective-C and Objective-C++ Dialects}.
 -mnorm -mspfp -mspfp-compact -mspfp-fast -msimd -msoft-float -mswap @gol
 -mcrc -mdsp-packa -mdvbf -mlock -mmac-d16 -mmac-24 -mrtsc -mswape @gol
 -mtelephony -mxy -misize -mannotate-align -marclinux -marclinux_prof @gol
--mepilogue-cfi -mlong-calls -mmedium-calls -msdata @gol
+-mlong-calls -mmedium-calls -msdata @gol
 -mucb-mcount -mvolatile-cache @gol
 -malign-call -mauto-modify-reg -mbbit-peephole -mno-brcc @gol
 -mcase-vector-pcrel -mcompact-casesi -mno-cond-exec -mearly-cbranchsi @gol
@@ -13121,14 +13121,6 @@ The following options control the semantics of generated code:
 
 @c semantically relevant code generation options
 @table @gcctabopt
-@item -mepilogue-cfi
-@opindex mepilogue-cfi
-Enable generation of call frame information for epilogues.
-
-@item -mno-epilogue-cfi
-@opindex mno-epilogue-cfi
-Disable generation of call frame information for epilogues.
-
 @item -mlong-calls
 @opindex mlong-calls
 Generate call insns as register indirect calls, thus providing access
-- 
1.9.1