Re: [PATCH] Emit Fortran PARAMETERs as DW_TAG_constant into debuginfo

[Laurent GUERBY <laurent at guerby dot net>]

I confirm the patch below is the source of the Ada bootstrap failure:
rev 139779 works and rev 139781 fails.

Laurent

On Sat, 2008-08-30 at 12:07 +0200, Laurent GUERBY wrote:
> Hi,
> 
> Ada currently fails to bootstrap on x86_64-linux at rev 139798
> 
> /home/guerby/build03/./prev-gcc/xgcc -B/home/guerby/build03/./prev-gcc/ -B/n/17/guerby/install03/x86_64-unknown-linux-gnu/bin/ -c -g -O2  -gnatpg -gnata -nostdinc -I- -I. -Iada -I../../trunk/gcc/ada -I../../trunk/gcc/ada/gcc-interface ../../trunk/gcc/ada/exp_attr.adb -o ada/exp_attr.o
> +===========================GNAT BUG DETECTED==============================+
> | 4.4.0 20080830 (experimental) [trunk revision 139798] (x86_64-unknown-linux-gnu) GCC error:|
> | in native_encode_initializer, at dwarf2out.c:11869                       |
> | Error detected around ../../trunk/gcc/ada/eval_fat.adb:898               |
> 
> Since your patch touches native_encode_initializer it might be
> the culprit, did you enable Ada during your test?
> 
> Thanks in advance,
> 
> Laurent
> 
> On Tue, 2008-08-26 at 14:45 -0400, Jakub Jelinek wrote:
> > Hi!
> > 
> > This patch emits Fortran PARAMETERs as DW_TAG_constant and unreferenced
> > non-use-associated variables with initializers as DW_TAG_variable with
> > DW_AT_const_value.
> > 
> > Regtested on x86_64-linux, ok for trunk?
> > 
> > 2008-08-26  Jakub Jelinek  <jakub@redhat.com>
> > 
> > 	* dwarf2out.c (gen_const_die): New function.
> > 	(size_of_die, value_format, output_die): Output larger
> > 	dw_val_class_vec using DW_FORM_block2 or DW_FORM_block4.
> > 	(native_encode_initializer): New function.
> > 	(tree_add_const_value_attribute): Call it.
> > 	(gen_decl_die, dwarf2out_decl): Handle CONST_DECLs if is_fortran ().
> > 
> > 	* trans-decl.c (check_constant_initializer,
> > 	gfc_emit_parameter_debug_info): New functions.
> > 	(gfc_generate_module_vars, gfc_generate_function_code): Emit
> > 	PARAMETERs and unreferenced variables with initializers into
> > 	debug info.
> > 
> > --- gcc/fortran/trans-decl.c.jj	2008-08-25 13:16:17.000000000 +0200
> > +++ gcc/fortran/trans-decl.c	2008-08-26 19:22:55.000000000 +0200
> > @@ -3232,6 +3232,134 @@ gfc_trans_use_stmts (gfc_namespace * ns)
> >  }
> >  
> > 
> > +/* Return true if expr is a constant initializer that gfc_conv_initializer
> > +   will handle.  */
> > +
> > +static bool
> > +check_constant_initializer (gfc_expr *expr, gfc_typespec *ts, bool array,
> > +			    bool pointer)
> > +{
> > +  gfc_constructor *c;
> > +  gfc_component *cm;
> > +
> > +  if (pointer)
> > +    return true;
> > +  else if (array)
> > +    {
> > +      if (expr->expr_type == EXPR_CONSTANT || expr->expr_type == EXPR_NULL)
> > +	return true;
> > +      else if (expr->expr_type == EXPR_STRUCTURE)
> > +	return check_constant_initializer (expr, ts, false, false);
> > +      else if (expr->expr_type != EXPR_ARRAY)
> > +	return false;
> > +      for (c = expr->value.constructor; c; c = c->next)
> > +	{
> > +	  if (c->iterator)
> > +	    return false;
> > +	  if (c->expr->expr_type == EXPR_STRUCTURE)
> > +	    {
> > +	      if (!check_constant_initializer (c->expr, ts, false, false))
> > +		return false;
> > +	    }
> > +	  else if (c->expr->expr_type != EXPR_CONSTANT)
> > +	    return false;
> > +	}
> > +      return true;
> > +    }
> > +  else switch (ts->type)
> > +    {
> > +    case BT_DERIVED:
> > +      if (expr->expr_type != EXPR_STRUCTURE)
> > +	return false;
> > +      cm = expr->ts.derived->components;
> > +      for (c = expr->value.constructor; c; c = c->next, cm = cm->next)
> > +	{
> > +	  if (!c->expr || cm->allocatable)
> > +	    continue;
> > +	  if (!check_constant_initializer (c->expr, &cm->ts, cm->dimension,
> > +					   cm->pointer))
> > +	    return false;
> > +	}
> > +      return true;
> > +    default:
> > +      return expr->expr_type == EXPR_CONSTANT;
> > +    }
> > +}
> > +
> > +/* Emit debug info for parameters and unreferenced variables with
> > +   initializers.  */
> > +
> > +static void
> > +gfc_emit_parameter_debug_info (gfc_symbol *sym)
> > +{
> > +  tree decl;
> > +
> > +  if (sym->attr.flavor != FL_PARAMETER
> > +      && (sym->attr.flavor != FL_VARIABLE || sym->attr.referenced))
> > +    return;
> > +
> > +  if (sym->backend_decl != NULL
> > +      || sym->value == NULL
> > +      || sym->attr.use_assoc
> > +      || sym->attr.dummy
> > +      || sym->attr.result
> > +      || sym->attr.function
> > +      || sym->attr.intrinsic
> > +      || sym->attr.pointer
> > +      || sym->attr.allocatable
> > +      || sym->attr.cray_pointee
> > +      || sym->attr.threadprivate
> > +      || sym->attr.is_bind_c
> > +      || sym->attr.subref_array_pointer
> > +      || sym->attr.assign)
> > +    return;
> > +
> > +  if (sym->ts.type == BT_CHARACTER)
> > +    {
> > +      gfc_conv_const_charlen (sym->ts.cl);
> > +      if (sym->ts.cl->backend_decl == NULL
> > +	  || TREE_CODE (sym->ts.cl->backend_decl) != INTEGER_CST)
> > +	return;
> > +    }
> > +  else if (sym->ts.type == BT_DERIVED && sym->ts.derived->attr.alloc_comp)
> > +    return;
> > +
> > +  if (sym->as)
> > +    {
> > +      int n;
> > +
> > +      if (sym->as->type != AS_EXPLICIT)
> > +	return;
> > +      for (n = 0; n < sym->as->rank; n++)
> > +	if (sym->as->lower[n]->expr_type != EXPR_CONSTANT
> > +	    || sym->as->upper[n] == NULL
> > +	    || sym->as->upper[n]->expr_type != EXPR_CONSTANT)
> > +	  return;
> > +    }
> > +
> > +  if (!check_constant_initializer (sym->value, &sym->ts,
> > +				   sym->attr.dimension, false))
> > +    return;
> > +
> > +  /* Create the decl for the variable or constant.  */
> > +  decl = build_decl (sym->attr.flavor == FL_PARAMETER ? CONST_DECL : VAR_DECL,
> > +		     gfc_sym_identifier (sym), gfc_sym_type (sym));
> > +  if (sym->attr.flavor == FL_PARAMETER)
> > +    TREE_READONLY (decl) = 1;
> > +  gfc_set_decl_location (decl, &sym->declared_at);
> > +  if (sym->attr.dimension)
> > +    GFC_DECL_PACKED_ARRAY (decl) = 1;
> > +  DECL_CONTEXT (decl) = sym->ns->proc_name->backend_decl;
> > +  TREE_STATIC (decl) = 1;
> > +  TREE_USED (decl) = 1;
> > +  if (DECL_CONTEXT (decl) && TREE_CODE (DECL_CONTEXT (decl)) == NAMESPACE_DECL)
> > +    TREE_PUBLIC (decl) = 1;
> > +  DECL_INITIAL (decl)
> > +    = gfc_conv_initializer (sym->value, &sym->ts, TREE_TYPE (decl),
> > +			    sym->attr.dimension, 0);
> > +  debug_hooks->global_decl (decl);
> > +}
> > +
> >  /* Generate all the required code for module variables.  */
> >  
> >  void
> > @@ -3252,6 +3380,7 @@ gfc_generate_module_vars (gfc_namespace 
> >    cur_module = NULL;
> >  
> >    gfc_trans_use_stmts (ns);
> > +  gfc_traverse_ns (ns, gfc_emit_parameter_debug_info);
> >  }
> >  
> > 
> > @@ -3787,6 +3916,7 @@ gfc_generate_function_code (gfc_namespac
> >      }
> >  
> >    gfc_trans_use_stmts (ns);
> > +  gfc_traverse_ns (ns, gfc_emit_parameter_debug_info);
> >  }
> >  
> >  void
> > --- gcc/dwarf2out.c.jj	2008-08-22 20:12:22.000000000 +0200
> > +++ gcc/dwarf2out.c	2008-08-26 19:46:49.000000000 +0200
> > @@ -5102,6 +5102,7 @@ static void gen_unspecified_parameters_d
> >  static void gen_formal_types_die (tree, dw_die_ref);
> >  static void gen_subprogram_die (tree, dw_die_ref);
> >  static void gen_variable_die (tree, dw_die_ref);
> > +static void gen_const_die (tree, dw_die_ref);
> >  static void gen_label_die (tree, dw_die_ref);
> >  static void gen_lexical_block_die (tree, dw_die_ref, int);
> >  static void gen_inlined_subroutine_die (tree, dw_die_ref, int);
> > @@ -7573,8 +7574,10 @@ size_of_die (dw_die_ref die)
> >  	  size += 1 + 2*HOST_BITS_PER_LONG/HOST_BITS_PER_CHAR; /* block */
> >  	  break;
> >  	case dw_val_class_vec:
> > -	  size += 1 + (a->dw_attr_val.v.val_vec.length
> > -		       * a->dw_attr_val.v.val_vec.elt_size); /* block */
> > +	  size += constant_size (a->dw_attr_val.v.val_vec.length
> > +				 * a->dw_attr_val.v.val_vec.elt_size)
> > +		  + a->dw_attr_val.v.val_vec.length
> > +		    * a->dw_attr_val.v.val_vec.elt_size; /* block */
> >  	  break;
> >  	case dw_val_class_flag:
> >  	  size += 1;
> > @@ -7773,7 +7776,18 @@ value_format (dw_attr_ref a)
> >      case dw_val_class_long_long:
> >        return DW_FORM_block1;
> >      case dw_val_class_vec:
> > -      return DW_FORM_block1;
> > +      switch (constant_size (a->dw_attr_val.v.val_vec.length
> > +			     * a->dw_attr_val.v.val_vec.elt_size))
> > +	{
> > +	case 1:
> > +	  return DW_FORM_block1;
> > +	case 2:
> > +	  return DW_FORM_block2;
> > +	case 4:
> > +	  return DW_FORM_block4;
> > +	default:
> > +	  gcc_unreachable ();
> > +	}
> >      case dw_val_class_flag:
> >        return DW_FORM_flag;
> >      case dw_val_class_die_ref:
> > @@ -8065,7 +8079,8 @@ output_die (dw_die_ref die)
> >  	    unsigned int i;
> >  	    unsigned char *p;
> >  
> > -	    dw2_asm_output_data (1, len * elt_size, "%s", name);
> > +	    dw2_asm_output_data (constant_size (len * elt_size),
> > +				 len * elt_size, "%s", name);
> >  	    if (elt_size > sizeof (HOST_WIDE_INT))
> >  	      {
> >  		elt_size /= 2;
> > @@ -11771,6 +11786,150 @@ add_location_or_const_value_attribute (d
> >    tree_add_const_value_attribute (die, decl);
> >  }
> >  
> > +/* Helper function for tree_add_const_value_attribute.  Natively encode
> > +   initializer INIT into an array.  Return true if successful.  */
> > +
> > +static bool
> > +native_encode_initializer (tree init, unsigned char *array, int size)
> > +{
> > +  tree type;
> > +
> > +  if (init == NULL_TREE)
> > +    return false;
> > +
> > +  STRIP_NOPS (init);
> > +  switch (TREE_CODE (init))
> > +    {
> > +    case STRING_CST:
> > +      type = TREE_TYPE (init);
> > +      if (TREE_CODE (type) == ARRAY_TYPE)
> > +	{
> > +	  tree enttype = TREE_TYPE (type);
> > +	  enum machine_mode mode = TYPE_MODE (enttype);
> > +
> > +	  if (GET_MODE_CLASS (mode) != MODE_INT || GET_MODE_SIZE (mode) != 1)
> > +	    return false;
> > +	  if (int_size_in_bytes (type) != size)
> > +	    return false;
> > +	  if (size > TREE_STRING_LENGTH (init))
> > +	    {
> > +	      memcpy (array, TREE_STRING_POINTER (init),
> > +		      TREE_STRING_LENGTH (init));
> > +	      memset (array + TREE_STRING_LENGTH (init),
> > +		      '\0', size - TREE_STRING_LENGTH (init));
> > +	    }
> > +	  else
> > +	    memcpy (array, TREE_STRING_POINTER (init), size);
> > +	  return true;
> > +	}
> > +      return false;
> > +    case CONSTRUCTOR:
> > +      type = TREE_TYPE (init);
> > +      if (int_size_in_bytes (type) != size)
> > +	return false;
> > +      if (TREE_CODE (type) == ARRAY_TYPE)
> > +	{
> > +	  HOST_WIDE_INT min_index;
> > +	  unsigned HOST_WIDE_INT cnt;
> > +	  int curpos = 0, fieldsize;
> > +	  constructor_elt *ce;
> > +
> > +	  if (TYPE_DOMAIN (type) == NULL_TREE
> > +	      || !host_integerp (TYPE_MIN_VALUE (TYPE_DOMAIN (type)), 0))
> > +	    return false;
> > +
> > +	  fieldsize = int_size_in_bytes (TREE_TYPE (type));
> > +	  if (fieldsize <= 0)
> > +	    return false;
> > +
> > +	  min_index = tree_low_cst (TYPE_MIN_VALUE (TYPE_DOMAIN (type)), 0);
> > +	  memset (array, '\0', size);
> > +	  for (cnt = 0;
> > +	       VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (init), cnt, ce);
> > +	       cnt++)
> > +	    {
> > +	      tree val = ce->value;
> > +	      tree index = ce->index;
> > +	      int pos = curpos;
> > +	      if (index && TREE_CODE (index) == RANGE_EXPR)
> > +		pos = (tree_low_cst (TREE_OPERAND (index, 0), 0) - min_index)
> > +		      * fieldsize;
> > +	      else if (index)
> > +		pos = tree_low_cst (index, 0) * fieldsize;
> > +
> > +	      if (val)
> > +		{
> > +		  STRIP_NOPS (val);
> > +		  if (!native_encode_initializer (val, array + pos, fieldsize))
> > +		    return false;
> > +		}
> > +	      curpos = pos + fieldsize;
> > +	      if (index && TREE_CODE (index) == RANGE_EXPR)
> > +		{
> > +		  int count = tree_low_cst (TREE_OPERAND (index, 1), 0)
> > +			      - tree_low_cst (TREE_OPERAND (index, 0), 0);
> > +		  while (count > 0)
> > +		    {
> > +		      if (val)
> > +			memcpy (array + curpos, array + pos, fieldsize);
> > +		      curpos += fieldsize;
> > +		    }
> > +		}
> > +	      gcc_assert (curpos <= size);
> > +	    }
> > +	  return true;
> > +	}
> > +      else if (TREE_CODE (type) == RECORD_TYPE
> > +	       || TREE_CODE (type) == UNION_TYPE)
> > +	{
> > +	  tree field = NULL_TREE;
> > +	  unsigned HOST_WIDE_INT cnt;
> > +	  constructor_elt *ce;
> > +
> > +	  if (int_size_in_bytes (type) != size)
> > +	    return false;
> > +
> > +	  if (TREE_CODE (type) == RECORD_TYPE)
> > +	    field = TYPE_FIELDS (type);
> > +
> > +	  for (cnt = 0;
> > +	       VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (init), cnt, ce);
> > +	       cnt++, field = field ? TREE_CHAIN (field) : 0)
> > +	    {
> > +	      tree val = ce->value;
> > +	      int pos, fieldsize;
> > +
> > +	      if (ce->index != 0)
> > +		field = ce->index;
> > +
> > +	      if (val)
> > +		STRIP_NOPS (val);
> > +
> > +	      if (field == NULL_TREE || DECL_BIT_FIELD (field))
> > +		return false;
> > +
> > +	      if (TREE_CODE (TREE_TYPE (field)) == ARRAY_TYPE
> > +		  && TYPE_DOMAIN (TREE_TYPE (field))
> > +		  && ! TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (field))))
> > +		return false;
> > +	      else if (DECL_SIZE_UNIT (field) == NULL_TREE
> > +		       || !host_integerp (DECL_SIZE_UNIT (field), 0))
> > +		return false;
> > +	      fieldsize = tree_low_cst (DECL_SIZE_UNIT (field), 0);
> > +	      pos = int_byte_position (field);
> > +	      gcc_assert (pos + fieldsize <= size);
> > +	      if (val
> > +		  && !native_encode_initializer (val, array + pos, fieldsize))
> > +		return false;
> > +	    }
> > +	  return true;
> > +	}
> > +      return false;
> > +    default:
> > +      return native_encode_expr (init, array, size) == size;
> > +    }
> > +}
> > +
> >  /* If we don't have a copy of this variable in memory for some reason (such
> >     as a C++ member constant that doesn't have an out-of-line definition),
> >     we should tell the debugger about the constant value.  */
> > @@ -11790,6 +11949,18 @@ tree_add_const_value_attribute (dw_die_r
> >    rtl = rtl_for_decl_init (init, type);
> >    if (rtl)
> >      add_const_value_attribute (var_die, rtl);
> > +  /* If the host and target are sane, try harder.  */
> > +  else if (CHAR_BIT == 8 && BITS_PER_UNIT == 8)
> > +    {
> > +      HOST_WIDE_INT size = int_size_in_bytes (TREE_TYPE (init));
> > +      if (size > 0 && (int) size == size)
> > +	{
> > +	  unsigned char *array = GGC_CNEWVEC (unsigned char, size);
> > +
> > +	  if (native_encode_initializer (init, array, size))
> > +	    add_AT_vec (var_die, DW_AT_const_value, size, 1, array);
> > +	}
> > +    }
> >  }
> >  
> >  /* Convert the CFI instructions for the current function into a
> > @@ -13752,6 +13923,24 @@ gen_variable_die (tree decl, dw_die_ref 
> >      tree_add_const_value_attribute (var_die, decl);
> >  }
> >  
> > +/* Generate a DIE to represent a named constant.  */
> > +
> > +static void
> > +gen_const_die (tree decl, dw_die_ref context_die)
> > +{
> > +  dw_die_ref const_die;
> > +  tree type = TREE_TYPE (decl);
> > +
> > +  const_die = new_die (DW_TAG_constant, context_die, decl);
> > +  add_name_and_src_coords_attributes (const_die, decl);
> > +  add_type_attribute (const_die, type, 1, 0, context_die);
> > +  if (TREE_PUBLIC (decl))
> > +    add_AT_flag (const_die, DW_AT_external, 1);
> > +  if (DECL_ARTIFICIAL (decl))
> > +    add_AT_flag (const_die, DW_AT_artificial, 1);
> > +  tree_add_const_value_attribute (const_die, decl);
> > +}
> > +
> >  /* Generate a DIE to represent a label identifier.  */
> >  
> >  static void
> > @@ -14892,8 +15081,20 @@ gen_decl_die (tree decl, dw_die_ref cont
> >        break;
> >  
> >      case CONST_DECL:
> > -      /* The individual enumerators of an enum type get output when we output
> > -	 the Dwarf representation of the relevant enum type itself.  */
> > +      if (!is_fortran ())
> > +	{
> > +	  /* The individual enumerators of an enum type get output when we output
> > +	     the Dwarf representation of the relevant enum type itself.  */
> > +	  break;
> > +	}
> > +
> > +      /* Emit its type.  */
> > +      gen_type_die (TREE_TYPE (decl), context_die);
> > +
> > +      /* And its containing namespace.  */
> > +      context_die = declare_in_namespace (decl, context_die);
> > +
> > +      gen_const_die (decl, context_die);
> >        break;
> >  
> >      case FUNCTION_DECL:
> > @@ -15238,6 +15439,15 @@ dwarf2out_decl (tree decl)
> >  	return;
> >        break;
> >  
> > +    case CONST_DECL:
> > +      if (debug_info_level <= DINFO_LEVEL_TERSE)
> > +	return;
> > +      if (!is_fortran ())
> > +	return;
> > +      if (TREE_STATIC (decl) && decl_function_context (decl))
> > +	context_die = lookup_decl_die (DECL_CONTEXT (decl));
> > +      break;
> > +
> >      case NAMESPACE_DECL:
> >        if (debug_info_level <= DINFO_LEVEL_TERSE)
> >  	return;
> > 
> > 	Jakub
> > 
> 
>