[PATCH] Fix DW_AT_frame_base with -fdwarf2-cfi-asm

[Jakub Jelinek <jakub at redhat dot com>]

On Mon, Jun 01, 2009 at 11:40:05AM +0200, Jakub Jelinek wrote:
> This seems not to be a bug in this weekend's patch, but a general
> problem with -fdwarf2-cfi-asm (so something that needs to be fixed there
> too).  convert_cfa_to_fb_loc_list can't work properly with .cfi_* directives
> in their current shape.  The only time convert_cfa_to_fb_loc_list actually
> appends something to the location lists for frame base is when
>       case DW_CFA_set_loc:
>       case DW_CFA_advance_loc1:
>       case DW_CFA_advance_loc2:
>       case DW_CFA_advance_loc4:
> but those aren't ever added when using .cfi_* directives (and what's worse,
> we don't emit labels at those instructions).
> 
> I'll try to fix this, but could the dwarf3 consumers in the mean time
> implement DW_OP_call_frame_cfa, pretty please, preferrably yesterday?

Here is the patch I'm bootstrapping/regtesting:

2009-06-01  Jakub Jelinek  <jakub@redhat.com>

	* dwarf2out.c (dwarf2out_cfi_label): Add FORCE argument, if true,
	force output of the label even for dwarf2out_do_cfi_asm.
	(add_fde_cfi): If -g2 and above and cfi might change CFA,
	force creation of CFI label and chain DW_CFA_set_loc jumping to it
	for convert_cfa_to_fb_loc_list.  Adjust other dwarf2out_cfi_label
	caller.
	(dwarf2out_stack_adjust, dwarf2out_frame_debug,
	dwarf2out_begin_epilogue, dwarf2out_frame_debug_restore_state): Adjust
	dwarf2out_cfi_label callers.
	* tree.h (dwarf2out_cfi_label): Adjust prototype.
	* config/arm/arm.c (thumb_pushpop, thumb1_output_function_prologue):
	Adjust dwarf2out_cfi_label callers.
	* config/vax/vax.c (vax_output_function_prologue): Likewise.

--- gcc/dwarf2out.c.jj	2009-05-30 10:13:04.000000000 +0200
+++ gcc/dwarf2out.c	2009-06-01 12:32:55.000000000 +0200
@@ -693,14 +693,15 @@ add_cfi (dw_cfi_ref *list_head, dw_cfi_r
   *p = cfi;
 }
 
-/* Generate a new label for the CFI info to refer to.  */
+/* Generate a new label for the CFI info to refer to.  FORCE is true
+   if a label needs to be output even when using .cfi_* directives.  */
 
 char *
-dwarf2out_cfi_label (void)
+dwarf2out_cfi_label (bool force)
 {
   static char label[20];
 
-  if (dwarf2out_do_cfi_asm ())
+  if (!force && dwarf2out_do_cfi_asm ())
     {
       /* In this case, we will be emitting the asm directive instead of
 	 the label, so just return a placeholder to keep the rest of the
@@ -728,11 +729,59 @@ add_fde_cfi (const char *label, dw_cfi_r
     {
       if (label)
 	{
-	  output_cfi_directive (cfi);
+	  dw_fde_ref fde = current_fde ();
+
+	  gcc_assert (fde != NULL);
 
 	  /* We still have to add the cfi to the list so that
-	     lookup_cfa works later on.  */
-	  list_head = &current_fde ()->dw_fde_cfi;
+	     lookup_cfa works later on.  When -g2 and above we
+	     even need to force emitting of CFI labels and
+	     add to list a DW_CFA_set_loc for convert_cfa_to_fb_loc_list
+	     purposes.  */
+	  switch (cfi->dw_cfi_opc)
+	    {
+	    case DW_CFA_def_cfa_offset:
+	    case DW_CFA_def_cfa_offset_sf:
+	    case DW_CFA_def_cfa_register:
+	    case DW_CFA_def_cfa:
+	    case DW_CFA_def_cfa_sf:
+	    case DW_CFA_def_cfa_expression:
+	    case DW_CFA_restore_state:
+	      if (write_symbols != DWARF2_DEBUG
+		  && write_symbols != VMS_AND_DWARF2_DEBUG)
+		break;
+	      if (debug_info_level <= DINFO_LEVEL_TERSE)
+		break;
+
+	      if (*label == 0 || strcmp (label, "<do not output>") == 0)
+		label = dwarf2out_cfi_label (true);
+
+	      if (fde->dw_fde_current_label == NULL
+		  || strcmp (label, fde->dw_fde_current_label) != 0)
+		{
+		  dw_cfi_ref xcfi;
+
+		  label = xstrdup (label);
+
+		  /* Set the location counter to the new label.  */
+		  xcfi = new_cfi ();
+		  /* It doesn't metter whether DW_CFA_set_loc
+		     or DW_CFA_advance_loc4 is added here, those aren't
+		     emitted into assembly, only looked up by
+		     convert_cfa_to_fb_loc_list.  */
+		  xcfi->dw_cfi_opc = DW_CFA_set_loc;
+		  xcfi->dw_cfi_oprnd1.dw_cfi_addr = label;
+		  add_cfi (&fde->dw_fde_cfi, xcfi);
+		  fde->dw_fde_current_label = label;
+		}
+	      break;
+	    default:
+	      break;
+	    }
+
+	  output_cfi_directive (cfi);
+
+	  list_head = &fde->dw_fde_cfi;
 	}
       /* ??? If this is a CFI for the CIE, we don't emit.  This
 	 assumes that the standard CIE contents that the assembler
@@ -747,7 +796,7 @@ add_fde_cfi (const char *label, dw_cfi_r
       gcc_assert (fde != NULL);
 
       if (*label == 0)
-	label = dwarf2out_cfi_label ();
+	label = dwarf2out_cfi_label (false);
 
       if (fde->dw_fde_current_label == NULL
 	  || strcmp (label, fde->dw_fde_current_label) != 0)
@@ -1477,7 +1526,7 @@ dwarf2out_stack_adjust (rtx insn, bool a
   if (offset == 0)
     return;
 
-  label = dwarf2out_cfi_label ();
+  label = dwarf2out_cfi_label (false);
   dwarf2out_args_size_adjust (offset, label);
 }
 
@@ -2580,7 +2629,7 @@ dwarf2out_frame_debug (rtx insn, bool af
       return;
     }
 
-  label = dwarf2out_cfi_label ();
+  label = dwarf2out_cfi_label (false);
 
   for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
     switch (REG_NOTE_KIND (note))
@@ -2709,7 +2758,7 @@ dwarf2out_begin_epilogue (rtx insn)
   /* Emit the state save.  */
   cfi = new_cfi (); 
   cfi->dw_cfi_opc = DW_CFA_remember_state;
-  add_fde_cfi (dwarf2out_cfi_label (), cfi);
+  add_fde_cfi (dwarf2out_cfi_label (false), cfi);
 
   /* And emulate the state save.  */
   gcc_assert (!cfa_remember.in_use);
@@ -2723,7 +2772,7 @@ void
 dwarf2out_frame_debug_restore_state (void)
 {
   dw_cfi_ref cfi = new_cfi (); 
-  const char *label = dwarf2out_cfi_label ();
+  const char *label = dwarf2out_cfi_label (false);
 
   cfi->dw_cfi_opc = DW_CFA_restore_state;
   add_fde_cfi (label, cfi);
--- gcc/tree.h.jj	2009-05-25 08:30:35.000000000 +0200
+++ gcc/tree.h	2009-06-01 12:06:21.000000000 +0200
@@ -5020,7 +5020,7 @@ extern tree tree_overlaps_hard_reg_set (
 
 /* Generate a new label for the CFI info to refer to.  */
 
-extern char *dwarf2out_cfi_label (void);
+extern char *dwarf2out_cfi_label (bool);
 
 /* Entry point to update the canonical frame address (CFA).  */
 
--- gcc/config/arm/arm.c.jj	2009-05-21 15:59:15.000000000 +0200
+++ gcc/config/arm/arm.c	2009-06-01 12:07:25.000000000 +0200
@@ -16984,7 +16984,7 @@ thumb_pushpop (FILE *f, unsigned long ma
 
   if (push && pushed_words && dwarf2out_do_frame ())
     {
-      char *l = dwarf2out_cfi_label ();
+      char *l = dwarf2out_cfi_label (false);
       int pushed_mask = real_regs;
 
       *cfa_offset += pushed_words * 4;
@@ -17880,7 +17880,7 @@ thumb1_output_function_prologue (FILE *f
 	 the stack pointer.  */
       if (dwarf2out_do_frame ())
 	{
-	  char *l = dwarf2out_cfi_label ();
+	  char *l = dwarf2out_cfi_label (false);
 
 	  cfa_offset = cfa_offset + crtl->args.pretend_args_size;
 	  dwarf2out_def_cfa (l, SP_REGNUM, cfa_offset);
@@ -17929,7 +17929,7 @@ thumb1_output_function_prologue (FILE *f
 
       if (dwarf2out_do_frame ())
 	{
-	  char *l = dwarf2out_cfi_label ();
+	  char *l = dwarf2out_cfi_label (false);
 
 	  cfa_offset = cfa_offset + 16;
 	  dwarf2out_def_cfa (l, SP_REGNUM, cfa_offset);
--- gcc/config/vax/vax.c.jj	2009-05-19 10:51:31.000000000 +0200
+++ gcc/config/vax/vax.c	2009-06-01 12:07:52.000000000 +0200
@@ -133,7 +133,7 @@ vax_output_function_prologue (FILE * fil
 
   if (dwarf2out_do_frame ())
     {
-      const char *label = dwarf2out_cfi_label ();
+      const char *label = dwarf2out_cfi_label (false);
       int offset = 0;
 
       for (regno = FIRST_PSEUDO_REGISTER-1; regno >= 0; --regno)


	Jakub