* alpha.c (alpha_ra_ever_killed): Inspect the topmost sequence,

        not whatever we're generating now.
        * alpha.c (set_frame_related_p, FRP): New.
        (alpha_expand_prologue): Mark frame related insns.
        (alpha_expand_epilogue): Likewise, but with a null FRP.
        * alpha.h (INCOMING_RETURN_ADDR_RTX): New.
        * alpha.md (exception_receiver): New.
        * alpha/crtbegin.asm (.eh_frame): New beginning.
        (__do_frame_setup, __do_frame_takedown): New.
        * alpha/crtend.asm (.eh_frame): New ending.
        * alpha/elf.h (DWARF2_DEBUGGING_INFO): Define.
        (ASM_SPEC): Don't emit both dwarf2 and mdebug.
        (ASM_FILE_START): Don't emit .file for dwarf2.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@22277 138bc75d-0d04-0410-961f-82ee72b054a4

7 files changed, 226 insertions, 61 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index dd5d66499dd..0f3b52e0c58 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,20 @@
 Sat Sep  5 22:05:25 1998  Richard Henderson  <rth@cygnus.com>
 
+	* alpha.c (alpha_ra_ever_killed): Inspect the topmost sequence,
+	not whatever we're generating now.
+
+	* alpha.c (set_frame_related_p, FRP): New.
+	(alpha_expand_prologue): Mark frame related insns.
+	(alpha_expand_epilogue): Likewise, but with a null FRP.
+	* alpha.h (INCOMING_RETURN_ADDR_RTX): New.
+	* alpha.md (exception_receiver): New.
+	* alpha/crtbegin.asm (.eh_frame): New beginning.
+	(__do_frame_setup, __do_frame_takedown): New.
+	* alpha/crtend.asm (.eh_frame): New ending.
+	* alpha/elf.h (DWARF2_DEBUGGING_INFO): Define.
+	(ASM_SPEC): Don't emit both dwarf2 and mdebug.
+	(ASM_FILE_START): Don't emit .file for dwarf2.
+
 	* rtl.h (enum reg_note): Add REG_FRAME_RELATED_EXPR.
 	* rtl.c (reg_note_name): Likewise.
 	* rtl.texi (REG_NOTES): Likewise.
diff --git a/gcc/config/alpha/alpha.c b/gcc/config/alpha/alpha.c
index 17cab88d8d5..e19ddab0fd8 100644
--- a/gcc/config/alpha/alpha.c
+++ b/gcc/config/alpha/alpha.c
@@ -2468,6 +2468,8 @@ alpha_return_addr (count, frame)
 static int
 alpha_ra_ever_killed ()
 {
+  rtx top;
+
 #ifdef ASM_OUTPUT_MI_THUNK
   if (current_function_is_thunk)
     return 0;
@@ -2475,8 +2477,11 @@ alpha_ra_ever_killed ()
   if (!alpha_return_addr_rtx)
     return regs_ever_live[REG_RA];
 
-  return reg_set_between_p (gen_rtx_REG (Pmode, REG_RA),
-			    get_insns(), NULL_RTX);
+  push_topmost_sequence ();
+  top = get_insns ();
+  pop_topmost_sequence ();
+
+  return reg_set_between_p (gen_rtx_REG (Pmode, REG_RA), top, NULL_RTX);
 }
 
 
@@ -3192,6 +3197,32 @@ alpha_write_verstamp (file)
 #endif
 }
 
+/* Helper function to set RTX_FRAME_RELATED_P on instructions, including
+   sequences.  */
+
+static rtx
+set_frame_related_p ()
+{
+  rtx seq = gen_sequence ();
+  end_sequence ();
+
+  if (GET_CODE (seq) == SEQUENCE)
+    {
+      int i = XVECLEN (seq, 0);
+      while (--i >= 0)
+	RTX_FRAME_RELATED_P (XVECEXP (seq, 0, i)) = 1;
+     return emit_insn (seq);
+    }
+  else
+    {
+      seq = emit_insn (seq);
+      RTX_FRAME_RELATED_P (seq) = 1;
+      return seq;
+    }
+}
+
+#define FRP(exp)  (start_sequence (), exp, set_frame_related_p ())
+
 /* Write function prologue.  */
 
 /* On vms we have two kinds of functions:
@@ -3271,8 +3302,8 @@ alpha_expand_prologue ()
 
       if (frame_size != 0)
 	{
-	  emit_move_insn (stack_pointer_rtx,
-			  plus_constant (stack_pointer_rtx, -frame_size));
+	  FRP (emit_move_insn (stack_pointer_rtx,
+			       plus_constant (stack_pointer_rtx, -frame_size)));
 	}
     }
   else
@@ -3302,7 +3333,18 @@ alpha_expand_prologue ()
 	  emit_move_insn (last, const0_rtx);
 	}
 
-      emit_move_insn (stack_pointer_rtx, plus_constant (ptr, -leftover));
+      ptr = emit_move_insn (stack_pointer_rtx, plus_constant (ptr, -leftover));
+
+      /* This alternative is special, because the DWARF code cannot possibly
+	 intuit through the loop above.  So we invent this note it looks at
+	 instead.  */
+      RTX_FRAME_RELATED_P (ptr) = 1;
+      REG_NOTES (ptr)
+	= gen_rtx_EXPR_LIST (REG_FRAME_RELATED_EXPR,
+			     gen_rtx_SET (VOIDmode, stack_pointer_rtx,
+			       gen_rtx_PLUS (Pmode, stack_pointer_rtx,
+					     GEN_INT (-frame_size))),
+			     REG_NOTES (ptr));
     }
 
   /* Cope with very large offsets to the register save area.  */
@@ -3318,21 +3360,22 @@ alpha_expand_prologue ()
 	bias = reg_offset, reg_offset = 0;
 
       sa_reg = gen_rtx_REG (DImode, 24);
-      emit_move_insn (sa_reg, plus_constant (stack_pointer_rtx, bias));
+      FRP (emit_move_insn (sa_reg, plus_constant (stack_pointer_rtx, bias)));
     }
     
   /* Save regs in stack order.  Beginning with VMS PV.  */
   if (TARGET_OPEN_VMS && vms_is_stack_procedure)
     {
-      emit_move_insn (gen_rtx_MEM (DImode, stack_pointer_rtx),
-		      gen_rtx_REG (DImode, REG_PV));
+      FRP (emit_move_insn (gen_rtx_MEM (DImode, stack_pointer_rtx),
+		           gen_rtx_REG (DImode, REG_PV)));
     }
 
   /* Save register RA next.  */
   if (imask & (1L << REG_RA))
     {
-      emit_move_insn (gen_rtx_MEM (DImode, plus_constant (sa_reg, reg_offset)),
-		      gen_rtx_REG (DImode, REG_RA));
+      FRP (emit_move_insn (gen_rtx_MEM (DImode,
+					plus_constant (sa_reg, reg_offset)),
+		           gen_rtx_REG (DImode, REG_RA)));
       imask &= ~(1L << REG_RA);
       reg_offset += 8;
     }
@@ -3341,18 +3384,18 @@ alpha_expand_prologue ()
   for (i = 0; i < 32; i++)
     if (imask & (1L << i))
       {
-	emit_move_insn (gen_rtx_MEM (DImode,
-				     plus_constant (sa_reg, reg_offset)),
-			gen_rtx_REG (DImode, i));
+	FRP (emit_move_insn (gen_rtx_MEM (DImode,
+				          plus_constant (sa_reg, reg_offset)),
+			     gen_rtx_REG (DImode, i)));
 	reg_offset += 8;
       }
 
   for (i = 0; i < 32; i++)
     if (fmask & (1L << i))
       {
-	emit_move_insn (gen_rtx_MEM (DFmode,
-				     plus_constant (sa_reg, reg_offset)),
-			gen_rtx_REG (DFmode, i+32));
+	FRP (emit_move_insn (gen_rtx_MEM (DFmode,
+				          plus_constant (sa_reg, reg_offset)),
+			     gen_rtx_REG (DFmode, i+32)));
 	reg_offset += 8;
       }
 
@@ -3361,25 +3404,25 @@ alpha_expand_prologue ()
       if (!vms_is_stack_procedure)
 	{
 	  /* Register frame procedures fave the fp.  */
-	  emit_move_insn (gen_rtx_REG (DImode, vms_save_fp_regno),
-			  hard_frame_pointer_rtx);
+	  FRP (emit_move_insn (gen_rtx_REG (DImode, vms_save_fp_regno),
+			       hard_frame_pointer_rtx));
 	}
 
       if (vms_base_regno != REG_PV)
-	emit_move_insn (gen_rtx_REG (DImode, vms_base_regno),
-			gen_rtx_REG (DImode, REG_PV));
+	FRP (emit_move_insn (gen_rtx_REG (DImode, vms_base_regno),
+			     gen_rtx_REG (DImode, REG_PV)));
 
       if (vms_unwind_regno == HARD_FRAME_POINTER_REGNUM)
 	{
-	  emit_move_insn (hard_frame_pointer_rtx, stack_pointer_rtx);
+	  FRP (emit_move_insn (hard_frame_pointer_rtx, stack_pointer_rtx));
 	}
 
       /* If we have to allocate space for outgoing args, do it now.  */
       if (current_function_outgoing_args_size != 0)
 	{
-	  emit_move_insn (stack_pointer_rtx, 
-	    plus_constant (hard_frame_pointer_rtx,
-	      - ALPHA_ROUND (current_function_outgoing_args_size)));
+	  FRP (emit_move_insn (stack_pointer_rtx, 
+	        plus_constant (hard_frame_pointer_rtx,
+	         - ALPHA_ROUND (current_function_outgoing_args_size))));
 	}
     }
   else
@@ -3388,13 +3431,13 @@ alpha_expand_prologue ()
       if (frame_pointer_needed)
 	{
 	  if (TARGET_CAN_FAULT_IN_PROLOGUE)
-	    emit_move_insn (hard_frame_pointer_rtx, stack_pointer_rtx);
+	    FRP (emit_move_insn (hard_frame_pointer_rtx, stack_pointer_rtx));
 	  else
 	    {
 	      /* This must always be the last instruction in the
 		 prologue, thus we emit a special move + clobber.  */
-	      emit_insn (gen_init_fp (hard_frame_pointer_rtx,
-				      stack_pointer_rtx, sa_reg));
+	      FRP (emit_insn (gen_init_fp (hard_frame_pointer_rtx,
+				           stack_pointer_rtx, sa_reg)));
 	    }
 	}
     }
@@ -3611,6 +3654,12 @@ output_end_prologue (file)
 
 /* Write function epilogue.  */
 
+/* ??? At some point we will want to support full unwind, and so will 
+   need to mark the epilogue as well.  At the moment, we just confuse
+   dwarf2out.  */
+#undef FRP
+#define FRP(exp) exp
+
 void
 alpha_expand_epilogue ()
 {
@@ -3659,7 +3708,7 @@ alpha_expand_epilogue ()
 	   && vms_unwind_regno == HARD_FRAME_POINTER_REGNUM)
 	  || (!TARGET_OPEN_VMS && frame_pointer_needed))
 	{
-	  emit_move_insn (stack_pointer_rtx, hard_frame_pointer_rtx);
+	  FRP (emit_move_insn (stack_pointer_rtx, hard_frame_pointer_rtx));
 	}
 
       /* Cope with very large offsets to the register save area.  */
@@ -3677,13 +3726,14 @@ alpha_expand_epilogue ()
 	  sa_reg = gen_rtx_REG (DImode, 22);
 	  sa_reg_exp = plus_constant (stack_pointer_rtx, bias);
 
-	  emit_move_insn (sa_reg, sa_reg_exp);
+	  FRP (emit_move_insn (sa_reg, sa_reg_exp));
 	}
 	  
       /* Restore registers in order, excepting a true frame pointer. */
 
-      emit_move_insn (gen_rtx_REG (DImode, REG_RA),
-		      gen_rtx_MEM (DImode, plus_constant(sa_reg, reg_offset)));
+      FRP (emit_move_insn (gen_rtx_REG (DImode, REG_RA),
+		           gen_rtx_MEM (DImode, plus_constant(sa_reg,
+							      reg_offset))));
       reg_offset += 8;
       imask &= ~(1L << REG_RA);
 
@@ -3694,10 +3744,10 @@ alpha_expand_epilogue ()
 	      fp_offset = reg_offset;
 	    else
 	      {
-		emit_move_insn (gen_rtx_REG (DImode, i),
-				gen_rtx_MEM (DImode,
-					     plus_constant(sa_reg,
-						           reg_offset)));
+		FRP (emit_move_insn (gen_rtx_REG (DImode, i),
+				     gen_rtx_MEM (DImode,
+					          plus_constant(sa_reg,
+						                reg_offset))));
 	      }
 	    reg_offset += 8;
 	  }
@@ -3705,9 +3755,10 @@ alpha_expand_epilogue ()
       for (i = 0; i < 32; ++i)
 	if (fmask & (1L << i))
 	  {
-	    emit_move_insn (gen_rtx_REG (DFmode, i+32),
-			    gen_rtx_MEM (DFmode,
-					 plus_constant(sa_reg, reg_offset)));
+	    FRP (emit_move_insn (gen_rtx_REG (DFmode, i+32),
+			         gen_rtx_MEM (DFmode,
+					      plus_constant(sa_reg,
+							    reg_offset))));
 	    reg_offset += 8;
 	  }
     }
@@ -3732,20 +3783,20 @@ alpha_expand_epilogue ()
 	  else
 	    {
 	      sp_adj1 = gen_rtx_REG (DImode, 23);
-	      emit_move_insn (sp_adj1, sp_adj2);
+	      FRP (emit_move_insn (sp_adj1, sp_adj2));
 	    }
 	  sp_adj2 = GEN_INT (low);
 	}
       else
 	{
 	  sp_adj2 = gen_rtx_REG (DImode, 23);
-	  sp_adj1 = alpha_emit_set_const (sp_adj2, DImode, frame_size, 3);
+	  FRP (sp_adj1 = alpha_emit_set_const (sp_adj2, DImode, frame_size, 3));
 	  if (!sp_adj1)
 	    {
 	      /* We can't drop new things to memory this late, afaik,
 		 so build it up by pieces.  */
 #if HOST_BITS_PER_WIDE_INT == 64
-	      sp_adj1 = alpha_emit_set_long_const (sp_adj2, frame_size);
+	      FRP (sp_adj1 = alpha_emit_set_long_const (sp_adj2, frame_size));
 	      if (!sp_adj1)
 		abort ();
 #else
@@ -3761,29 +3812,29 @@ alpha_expand_epilogue ()
       if (fp_is_frame_pointer)
 	{
 	  emit_insn (gen_blockage ());
-	  emit_move_insn (hard_frame_pointer_rtx,
-			  gen_rtx_MEM (DImode,
-				       plus_constant(sa_reg, fp_offset)));
+	  FRP (emit_move_insn (hard_frame_pointer_rtx,
+			       gen_rtx_MEM (DImode,
+				            plus_constant(sa_reg, fp_offset))));
 	}
       else if (TARGET_OPEN_VMS)
 	{
 	  emit_insn (gen_blockage ());
-	  emit_move_insn (hard_frame_pointer_rtx,
-			  gen_rtx_REG (DImode, vms_save_fp_regno));
+	  FRP (emit_move_insn (hard_frame_pointer_rtx,
+			       gen_rtx_REG (DImode, vms_save_fp_regno)));
 	}
 
       /* Restore the stack pointer.  */
       emit_insn (gen_blockage ());
-      emit_move_insn (stack_pointer_rtx,
-		      gen_rtx_PLUS (DImode, sp_adj1, sp_adj2));
+      FRP (emit_move_insn (stack_pointer_rtx,
+		           gen_rtx_PLUS (DImode, sp_adj1, sp_adj2)));
     }
   else 
     {
       if (TARGET_OPEN_VMS && !vms_is_stack_procedure)
         {
           emit_insn (gen_blockage ());
-          emit_move_insn (hard_frame_pointer_rtx,
-			  gen_rtx_REG (DImode, vms_save_fp_regno));
+          FRP (emit_move_insn (hard_frame_pointer_rtx,
+			       gen_rtx_REG (DImode, vms_save_fp_regno)));
         }
     }
 
diff --git a/gcc/config/alpha/alpha.h b/gcc/config/alpha/alpha.h
index b77f3b9e855..9aacab5d833 100644
--- a/gcc/config/alpha/alpha.h
+++ b/gcc/config/alpha/alpha.h
@@ -1301,6 +1301,9 @@ extern void alpha_initialize_trampoline ();
 #define RETURN_ADDR_RTX  alpha_return_addr
 extern struct rtx_def *alpha_return_addr ();
 
+/* Before the prologue, RA lives in $26. */
+#define INCOMING_RETURN_ADDR_RTX  gen_rtx_REG (Pmode, 26)
+
 /* Initialize data used by insn expanders.  This is called from insn_emit,
    once for every function before code is generated.  */
 
diff --git a/gcc/config/alpha/alpha.md b/gcc/config/alpha/alpha.md
index 89184bf25b3..232fb01def1 100644
--- a/gcc/config/alpha/alpha.md
+++ b/gcc/config/alpha/alpha.md
@@ -39,6 +39,7 @@
 ;;	4	trapb
 ;;	5	prologue_stack_probe_loop
 ;;	6	realign
+;;	7	exception_receiver
 
 ;; Processor type -- this attribute must exactly match the processor_type
 ;; enumeration in alpha.h.
@@ -5177,7 +5178,14 @@
 (define_insn ""
   [(unspec_volatile [(match_operand 0 "" "")] 2)]
   "! TARGET_OPEN_VMS && ! TARGET_WINDOWS_NT"
-  "br $27,$LSJ%=\\n$LSJ%=:\;ldgp $29,0($27)"
+  "br $29,$LSJ%=\\n$LSJ%=:\;ldgp $29,0($29)"
+  [(set_attr "length" "12")
+   (set_attr "type" "multi")])
+
+(define_insn "exception_receiver"
+  [(unspec_volatile [(const_int 0)] 7)]
+  "! TARGET_OPEN_VMS && ! TARGET_WINDOWS_NT"
+  "br $29,$LSJ%=\\n$LSJ%=:\;ldgp $29,0($29)"
   [(set_attr "length" "12")
    (set_attr "type" "multi")])
 
diff --git a/gcc/config/alpha/crtbegin.asm b/gcc/config/alpha/crtbegin.asm
index c28440d8a24..f954f1ab0d3 100644
--- a/gcc/config/alpha/crtbegin.asm
+++ b/gcc/config/alpha/crtbegin.asm
@@ -50,6 +50,8 @@ __CTOR_LIST__:
 __DTOR_LIST__:
 	.quad -1
 
+.section .eh_frame,"aw"
+__EH_FRAME_BEGIN__:
 
  #
  # Fragment of the ELF _fini routine that invokes our dtor cleanup.
@@ -67,18 +69,33 @@ __DTOR_LIST__:
 1:	ldgp    $29,0($29)
 	jsr     $26,__do_global_dtors_aux
 
+	# Ideally this call would go in crtend.o, except that we can't
+	# get hold of __EH_FRAME_BEGIN__ there.
+
+	jsr	$26,__do_frame_takedown
+
 	# Must match the alignment we got from crti.o else we get
 	# zero-filled holes in our _fini function and then SIGILL.
 	.align 3
 
  #
+ # Fragment of the ELF _init routine that sets up the frame info.
+ #
+
+.section .init,"ax"
+       br      $29,1f
+1:     ldgp    $29,0($29)
+       jsr     $26,__do_frame_setup
+       .align 3
+
+ #
  # Invoke our destructors in order.
  #
 
 .data
 
  # Support recursive calls to exit.
-9:	.quad	__DTOR_LIST__
+$ptr:	.quad	__DTOR_LIST__
 
 .text
 
@@ -86,15 +103,14 @@ __DTOR_LIST__:
 	.ent __do_global_dtors_aux
 
 __do_global_dtors_aux:
-	ldgp	$29,0($27)
 	lda     $30,-16($30)
 	.frame  $30,16,$26,0
 	stq	$9,8($30)
 	stq     $26,0($30)
 	.mask   0x4000200,-16
-	.prologue 1
+	.prologue 0
 
-	lda     $9,9b
+	lda     $9,$ptr
 	br      1f
 0:	stq	$1,0($9)
 	jsr     $26,($27)
@@ -109,3 +125,68 @@ __do_global_dtors_aux:
 	ret
 
 	.end __do_global_dtors_aux
+
+ #
+ # Install our frame info.
+ #
+
+ # ??? How can we rationally keep this size correct?
+
+.section .bss
+	.type $object,@object
+	.align 3
+$object:
+	.zero 48
+	.size $object, 48
+
+.text 
+
+	.align 3
+	.ent __do_frame_setup
+
+__do_frame_setup:
+	ldgp	$29,0($27)
+	lda     $30,-16($30)
+	.frame  $30,16,$26,0
+	stq     $26,0($30)
+	.mask   0x4000000,-16
+	.prologue 1
+
+	lda	$1,__register_frame_info
+	beq	$1,0f
+	lda	$16,__EH_FRAME_BEGIN__
+	lda	$17,$object
+	jsr	$26,__register_frame_info
+	ldq     $26,0($30)
+0:	lda     $30,16($30)
+	ret
+
+	.end __do_frame_setup
+
+ #
+ # Remove our frame info.
+ #
+
+	.align 3
+	.ent __do_frame_takedown
+
+__do_frame_takedown:
+	ldgp	$29,0($27)
+	lda     $30,-16($30)
+	.frame  $30,16,$26,0
+	stq     $26,0($30)
+	.mask   0x4000000,-16
+	.prologue 1
+
+	lda	$1,__deregister_frame_info
+	beq	$1,0f
+	lda	$16,__EH_FRAME_BEGIN__
+	jsr	$26,__deregister_frame_info
+	ldq     $26,0($30)
+0:	lda     $30,16($30)
+	ret
+
+	.end __do_frame_takedown
+
+.weak __register_frame_info
+.weak __deregister_frame_info
diff --git a/gcc/config/alpha/crtend.asm b/gcc/config/alpha/crtend.asm
index 36f11b9723a..4a0cc5e9f61 100644
--- a/gcc/config/alpha/crtend.asm
+++ b/gcc/config/alpha/crtend.asm
@@ -50,6 +50,9 @@ __CTOR_END__:
 __DTOR_END__:
 	.quad   0
 
+.section .eh_frame,"aw"
+__FRAME_END__:
+	.quad	0
 
  #
  # Fragment of the ELF _init routine that invokes our ctor startup
diff --git a/gcc/config/alpha/elf.h b/gcc/config/alpha/elf.h
index 4f4703c14ef..89eda748c06 100644
--- a/gcc/config/alpha/elf.h
+++ b/gcc/config/alpha/elf.h
@@ -24,6 +24,7 @@ Boston, MA 02111-1307, USA.    */
 #define OBJECT_FORMAT_ELF
 
 #define DBX_DEBUGGING_INFO
+#define DWARF2_DEBUGGING_INFO
 
 #undef PREFERRED_DEBUGGING_TYPE
 #define PREFERRED_DEBUGGING_TYPE DBX_DEBUG
@@ -34,7 +35,7 @@ Boston, MA 02111-1307, USA.    */
 #define CC1_SPEC  "%{G*}"
 
 #undef ASM_SPEC
-#define ASM_SPEC  "%{G*} %{relax:-relax}"
+#define ASM_SPEC  "%{G*} %{relax:-relax} %{gdwarf*:-no-mdebug}"
 
 #undef LINK_SPEC
 #define LINK_SPEC "-m elf64alpha %{G*} %{relax:-relax}		\
@@ -49,18 +50,21 @@ Boston, MA 02111-1307, USA.    */
 /* Output at beginning of assembler file.  */
 #undef ASM_FILE_START
 #define ASM_FILE_START(FILE)					\
-{								\
-  alpha_write_verstamp (FILE);					\
-  output_file_directive (FILE, main_input_filename);		\
+do {								\
+  if (write_symbols != DWARF2_DEBUG)				\
+    {								\
+      alpha_write_verstamp (FILE);				\
+      output_file_directive (FILE, main_input_filename);	\
+    }								\
   fprintf (FILE, "\t.set noat\n");				\
-  fprintf (FILE, "\t.set noreorder\n");                         \
+  fprintf (FILE, "\t.set noreorder\n");				\
   if (TARGET_BWX | TARGET_MAX | TARGET_CIX)			\
     {								\
       fprintf (FILE, "\t.arch %s\n",				\
                (alpha_cpu == PROCESSOR_EV6 ? "ev6"		\
                 : TARGET_MAX ? "pca56" : "ev56"));		\
     }								\
-}
+} while (0)
 
 extern void output_file_directive ();