[ARC] Fix to unwinding.

gcc/ChangeLog:
2017-11-03  Cupertino Miranda  <cmiranda@synopsys.com>

        * config/arc/arc.c (arc_save_restore): Corrected CFA note.
        (arc_expand_prologue): Restore blink for millicode.
        * config/arc/linux.h (LINK_EH_SPEC): Defined.

libgcc/ChangeLog:
2017-11-03  Cupertino Miranda  <cmiranda@synopsys.com>
            Vineet Gupta <vgupta@synopsys.com>

        * config.host (arc*-*-linux*): Set md_unwind_header variable.
        * config/arc/linux-unwind-reg.def: New file.
        * config/arc/linux-unwind.h: Likewise.

Co-Authored-By: Vineet Gupta <vgupta@synopsys.com>

From-SVN: r254367

gcc/ChangeLog

+2017-11-03  Cupertino Miranda  <cmiranda@synopsys.com>
+
+	* config/arc/arc.c (arc_save_restore): Corrected CFA note.
+	(arc_expand_prologue): Restore blink for millicode.
+	* config/arc/linux.h (LINK_EH_SPEC): Defined.
+
 2017-11-03  Richard Sandiford  <richard.sandiford@linaro.org>
 
 	PR target/82809

gcc/config/arc/arc.c

@@ -2823,12 +2823,23 @@ arc_save_restore (rtx base_reg,
 	  else
 	    {
 	      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);
-		  }
+	      for (r = start_call, off = 0;
+		   r <= end_call;
+		   r++, off += UNITS_PER_WORD)
+		{
+		  rtx reg = gen_rtx_REG (SImode, r);
+		  if (epilogue_p)
+		      add_reg_note (insn, REG_CFA_RESTORE, reg);
+		  else
+		    {
+		      rtx mem = gen_rtx_MEM (SImode, plus_constant (Pmode,
+								    base_reg,
+								    off));
+
+		      add_reg_note (insn, REG_CFA_OFFSET,
+				    gen_rtx_SET (mem, reg));
+		    }
+		}
 	    }
 	  offset += off;
 	}
@@ -3070,6 +3081,19 @@ arc_expand_prologue (void)
       frame_size_to_allocate -= cfun->machine->frame_info.reg_size;
     }
 
+  /* In the case of millicode thunk, we need to restore the clobbered
+     blink register.  */
+  if (cfun->machine->frame_info.millicode_end_reg > 0
+      && arc_must_save_return_addr (cfun))
+    {
+      HOST_WIDE_INT tmp = cfun->machine->frame_info.reg_size;
+      emit_insn (gen_rtx_SET (gen_rtx_REG (Pmode, RETURN_ADDR_REGNUM),
+			      gen_rtx_MEM (Pmode,
+					   plus_constant (Pmode,
+							  stack_pointer_rtx,
+							  tmp))));
+    }
+
   /* Save frame pointer if needed.  First save the FP on stack, if not
      autosaved.  */
   if (arc_frame_pointer_needed ()

gcc/config/arc/linux.h

@@ -91,3 +91,11 @@ along with GCC; see the file COPYING3.  If not see
 /* Pre/post modify with register displacement are default off.  */
 #undef TARGET_AUTO_MODIFY_REG_DEFAULT
 #define TARGET_AUTO_MODIFY_REG_DEFAULT 0
+
+#if DEFAULT_LIBC == LIBC_GLIBC
+/* Override linux.h LINK_EH_SPEC definition.
+   Signalize that because we have fde-glibc, we don't need all C shared libs
+   linked against -lgcc_s.  */
+#undef LINK_EH_SPEC
+#define LINK_EH_SPEC "--eh-frame-hdr"
+#endif

libgcc/ChangeLog

+2017-11-03  Cupertino Miranda  <cmiranda@synopsys.com>
+	    Vineet Gupta <vgupta@synopsys.com>
+
+	* config.host (arc*-*-linux*): Set md_unwind_header variable.
+	* config/arc/linux-unwind-reg.def: New file.
+	* config/arc/linux-unwind-reg.h: Likewise.
+
 2017-10-23  Sebastian Perta  <sebastian.perta@renesas.com>
 
 	* config/rl78/subdi3.S: New assembly file.

libgcc/config.host

@@ -390,6 +390,7 @@ arc*-*-linux*)
 	tmake_file="${tmake_file} t-slibgcc-libgcc t-slibgcc-nolc-override arc/t-arc-uClibc arc/t-arc"
 	extra_parts="$extra_parts crti.o crtn.o"
 	extra_parts="$extra_parts crttls.o"
+	md_unwind_header=arc/linux-unwind.h
 	;;
 arm-wrs-vxworks|arm-wrs-vxworks7)
 	tmake_file="$tmake_file arm/t-arm arm/t-elf t-softfp-sfdf t-softfp-excl arm/t-softfp t-softfp"

libgcc/config/arc/linux-unwind-reg.def

+/* Copyright (C) 2017 Free Software Foundation, Inc.
+
+   This file is part of GCC.
+
+   GCC is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   GCC is distributed in the hope that it will be useful, but WITHOUT
+   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+   License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GCC; see the file COPYING3.  If not see
+   <http://www.gnu.org/licenses/>.
+*/
+
+REGISTER_IN_STACK(bta, -1)
+REGISTER_IN_STACK(lp_start, -1)
+REGISTER_IN_STACK(lp_end, -1)
+REGISTER_IN_STACK(lp_count, -1)
+REGISTER_IN_STACK(status32, -1)
+REGISTER_IN_STACK(ret, -1)
+REGISTER_IN_STACK(blink, 31)
+REGISTER_IN_STACK(fp, 27)
+REGISTER_IN_STACK(gp, 26)
+REGISTER_IN_STACK(r12, 12)
+REGISTER_IN_STACK(r11, 11)
+REGISTER_IN_STACK(r10, 10)
+REGISTER_IN_STACK(r9, 9)
+REGISTER_IN_STACK(r8, 8)
+REGISTER_IN_STACK(r7, 7)
+REGISTER_IN_STACK(r6, 6)
+REGISTER_IN_STACK(r5, 5)
+REGISTER_IN_STACK(r4, 4)
+REGISTER_IN_STACK(r3, 3)
+REGISTER_IN_STACK(r2, 2)
+REGISTER_IN_STACK(r1, 1)
+REGISTER_IN_STACK(r0, 0)
+REGISTER_IN_STACK(sp, 28)

libgcc/config/arc/linux-unwind.h

+/* DWARF2 EH unwinding support for ARC Linux.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+   This file is part of GCC.
+
+   GCC is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   GCC is distributed in the hope that it will be useful, but WITHOUT
+   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+   License for more details.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as published by the Free Software Foundation.
+
+   You should have received a copy of the GNU General Public License
+   and a copy of the GCC Runtime Library Exception along with this
+   program; see the files COPYING3 and COPYING.RUNTIME respectively.
+   If not, see <http://www.gnu.org/licenses/>.  */
+
+/* This order is defined by a structure in the kernel, in file
+   arch/arc/kernel/signal.c.  */
+
+#define REGISTER_IN_STACK(REG_NAME, ID) \
+  REG_NAME,
+enum registers_stack_order {
+  REGISTER_STACK_ORDER_START = -1,
+  #include "config/arc/linux-unwind-reg.def"
+  REGISTER_STACK_ORDER_SIZE,
+};
+
+struct register_position {
+  int reg_id;
+  int offset_in_stack;
+};
+#undef REGISTER_IN_STACK
+
+#define REGISTER_SIZE_IN_WORDS 4
+#define REGISTER_IN_STACK(REG_NAME, ID) (int) ID,
+int
+register_id_for_index[REGISTER_STACK_ORDER_SIZE] = {
+  #include "config/arc/linux-unwind-reg.def"
+};
+#undef REGISTER_IN_STACK
+
+#ifndef inhibit_libc
+/* Do code reading to identify a signal frame, and set the frame
+   state data appropriately.  See unwind-dw2.c for the structs.  */
+
+#include <signal.h>
+#include <asm/unistd.h>
+
+/*
+00010edc <__default_rt_sa_restorer>:
+   10edc:	208a 12c2		mov     r8,139
+   10ee0:	781e			trap_s  0
+   10ee2:	7ee0			j_s     [blink]
+*/
+
+#if __BIG_ENDIAN__
+#define MOV_R8_139	  0x8a20c212
+#define TRAP_S_J_S_BLINK  0x1e78e07e
+#define SWI		  0x6f223f00
+#elif __LITTLE_ENDIAN__
+#define MOV_R8_139	  0x12c2208a
+#define TRAP_S_J_S_BLINK  0x7ee0781e
+#define SWI		  0x003f226f
+#endif
+
+#define MD_FALLBACK_FRAME_STATE_FOR arc_fallback_frame_state
+
+static __attribute__((noinline)) _Unwind_Reason_Code
+arc_fallback_frame_state (struct _Unwind_Context *context,
+			   _Unwind_FrameState *fs)
+{
+  struct rt_sigframe {
+    siginfo_t info;
+    ucontext_t uc;
+    unsigned int sigret_magic;
+  };
+
+  struct rt_sigframe *rt_;
+  u_int32_t *pc = (u_int32_t *) context->ra;
+  struct sigcontext *sc;
+  _Unwind_Ptr new_cfa;
+  int i;
+
+#ifdef __ARC700__
+  if (pc[1] != SWI)
+    return _URC_END_OF_STACK;
+#else
+  if (pc[1] != TRAP_S_J_S_BLINK)
+    return _URC_END_OF_STACK;
+#endif
+
+  if (pc[0] == MOV_R8_139)
+    {
+      rt_ = context->cfa;
+      sc = &rt_->uc.uc_mcontext;
+    }
+  else
+    return _URC_END_OF_STACK;
+
+  new_cfa = (_Unwind_Ptr) sc;
+  fs->regs.cfa_how = CFA_REG_OFFSET;
+  fs->regs.cfa_reg = __LIBGCC_STACK_POINTER_REGNUM__;
+  fs->regs.cfa_offset = new_cfa - (_Unwind_Ptr) context->cfa;
+
+  unsigned long *regs = &sc->regs.scratch.bta;
+  for (i = 0; i < REGISTER_STACK_ORDER_SIZE; i++)
+    {
+      if (register_id_for_index[i] == -1)
+	continue;
+      fs->regs.reg[register_id_for_index[i]].how = REG_SAVED_OFFSET;
+      fs->regs.reg[register_id_for_index[i]].loc.offset
+	= ((_Unwind_Ptr) &(regs[i])) - new_cfa;
+    }
+
+  fs->regs.reg[31].how = REG_SAVED_VAL_OFFSET;
+  fs->regs.reg[31].loc.offset = ((_Unwind_Ptr) (regs[ret])) - new_cfa;
+
+  fs->retaddr_column = 31;
+
+  return _URC_NO_REASON;
+}
+#endif
+
+#define MD_FROB_UPDATE_CONTEXT arc_frob_update_context
+/* Save fp register for unwinding to work.  */
+
+static void
+arc_frob_update_context (struct _Unwind_Context *context,
+			 _Unwind_FrameState *fs)
+{
+  _Unwind_Word fp_val;
+  asm ("mov %0,fp" : "=r" (fp_val));
+
+  switch (fs->regs.reg[27].how)
+    {
+    case REG_UNSAVED:
+    case REG_UNDEFINED:
+      if (context->reg[27] == NULL)
+	_Unwind_SetGRValue (context, 27, fp_val);
+      break;
+
+    default:
+      break;
+    }
+}