dbxout.c

gcc库的原代码,对编程有很大帮助.

	  putc (';', asmfile);
	  CHARS (3);
	}
      break;

    case ENUMERAL_TYPE:
      /* We must use the same test here as we use in the DBX_NO_XREFS case
	 above.  We simplify it a bit since an enum will never have a variable
	 size.  */
      if ((TYPE_NAME (type) != 0
	   && ! (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
		 && DECL_IGNORED_P (TYPE_NAME (type)))
	   && !full)
	  || TYPE_SIZE (type) == 0)
	{
	  fprintf (asmfile, "xe");
	  CHARS (3);
	  dbxout_type_name (type);
	  typevec[TYPE_SYMTAB_ADDRESS (type)] = TYPE_XREF;
	  fprintf (asmfile, ":");
	  return;
	}
#ifdef DBX_OUTPUT_ENUM
      DBX_OUTPUT_ENUM (asmfile, type);
#else
      if (use_gnu_debug_info_extensions
	  && TYPE_PRECISION (type) != TYPE_PRECISION (integer_type_node))
	fprintf (asmfile, "@s%d;", TYPE_PRECISION (type));
      putc ('e', asmfile);
      CHARS (1);
      for (tem = TYPE_VALUES (type); tem; tem = TREE_CHAIN (tem))
	{
	  fprintf (asmfile, "%s:", IDENTIFIER_POINTER (TREE_PURPOSE (tem)));
	  if (TREE_INT_CST_HIGH (TREE_VALUE (tem)) == 0)
	    fprintf (asmfile, "%lu",
		     (unsigned long) TREE_INT_CST_LOW (TREE_VALUE (tem)));
	  else if (TREE_INT_CST_HIGH (TREE_VALUE (tem)) == -1
		   && TREE_INT_CST_LOW (TREE_VALUE (tem)) < 0)
	    fprintf (asmfile, "%ld",
		     (long) TREE_INT_CST_LOW (TREE_VALUE (tem)));
	  else
	    print_int_cst_octal (TREE_VALUE (tem));
	  fprintf (asmfile, ",");
	  CHARS (20 + IDENTIFIER_LENGTH (TREE_PURPOSE (tem)));
	  if (TREE_CHAIN (tem) != 0)
	    CONTIN;
	}
      putc (';', asmfile);
      CHARS (1);
#endif
      break;

    case POINTER_TYPE:
      putc ('*', asmfile);
      CHARS (1);
      dbxout_type (TREE_TYPE (type), 0, 0);
      break;

    case METHOD_TYPE:
      if (use_gnu_debug_info_extensions)
	{
	  have_used_extensions = 1;
	  putc ('#', asmfile);
	  CHARS (1);
	  if (flag_minimal_debug && !show_arg_types)
	    {
	      /* Normally, just output the return type.
		 The argument types are encoded in the method name.  */
	      putc ('#', asmfile);
	      dbxout_type (TREE_TYPE (type), 0, 0);
	      putc (';', asmfile);
	      CHARS (1);
	    }
	  else
	    {
	      /* When outputting destructors, we need to write
		 the argument types out longhand.  */
	      dbxout_type (TYPE_METHOD_BASETYPE (type), 0, 0);
	      putc (',', asmfile);
	      CHARS (1);
	      dbxout_type (TREE_TYPE (type), 0, 0);
	      dbxout_args (TYPE_ARG_TYPES (type));
	      putc (';', asmfile);
	      CHARS (1);
	    }
	}
      else
	{
	  /* Treat it as a function type.  */
	  dbxout_type (TREE_TYPE (type), 0, 0);
	}
      break;

    case OFFSET_TYPE:
      if (use_gnu_debug_info_extensions)
	{
	  have_used_extensions = 1;
	  putc ('@', asmfile);
	  CHARS (1);
	  dbxout_type (TYPE_OFFSET_BASETYPE (type), 0, 0);
	  putc (',', asmfile);
	  CHARS (1);
	  dbxout_type (TREE_TYPE (type), 0, 0);
	}
      else
	{
	  /* Should print as an int, because it is really
	     just an offset.  */
	  dbxout_type (integer_type_node, 0, 0);
	}
      break;

    case REFERENCE_TYPE:
      if (use_gnu_debug_info_extensions)
	have_used_extensions = 1;
      putc (use_gnu_debug_info_extensions ? '&' : '*', asmfile);
      CHARS (1);
      dbxout_type (TREE_TYPE (type), 0, 0);
      break;

    case FUNCTION_TYPE:
      putc ('f', asmfile);
      CHARS (1);
      dbxout_type (TREE_TYPE (type), 0, 0);
      break;

    default:
      abort ();
    }
}

/* Print the value of integer constant C, in octal,
   handling double precision.  */

static void
print_int_cst_octal (c)
     tree c;
{
  unsigned HOST_WIDE_INT high = TREE_INT_CST_HIGH (c);
  unsigned HOST_WIDE_INT low = TREE_INT_CST_LOW (c);
  int excess = (3 - (HOST_BITS_PER_WIDE_INT % 3));
  int width = TYPE_PRECISION (TREE_TYPE (c));

  /* GDB wants constants with no extra leading "1" bits, so
     we need to remove any sign-extension that might be
     present.  */
  if (width == HOST_BITS_PER_WIDE_INT * 2)
    ;
  else if (width > HOST_BITS_PER_WIDE_INT)
    high &= (((HOST_WIDE_INT) 1 << (width - HOST_BITS_PER_WIDE_INT)) - 1);
  else if (width == HOST_BITS_PER_WIDE_INT)
    high = 0;
  else
    high = 0, low &= (((HOST_WIDE_INT) 1 << width) - 1);

  fprintf (asmfile, "0");

  if (excess == 3)
    {
      print_octal (high, HOST_BITS_PER_WIDE_INT / 3);
      print_octal (low, HOST_BITS_PER_WIDE_INT / 3);
    }
  else
    {
      unsigned HOST_WIDE_INT beg = high >> excess;
      unsigned HOST_WIDE_INT middle
	= ((high & (((HOST_WIDE_INT) 1 << excess) - 1)) << (3 - excess)
	   | (low >> (HOST_BITS_PER_WIDE_INT / 3 * 3)));
      unsigned HOST_WIDE_INT end
	= low & (((unsigned HOST_WIDE_INT) 1
		  << (HOST_BITS_PER_WIDE_INT / 3 * 3))
		 - 1);

      fprintf (asmfile, "%o%01o", beg, middle);
      print_octal (end, HOST_BITS_PER_WIDE_INT / 3);
    }
}

static void
print_octal (value, digits)
     unsigned HOST_WIDE_INT value;
     int digits;
{
  int i;

  for (i = digits - 1; i >= 0; i--)
    fprintf (asmfile, "%01o", ((value >> (3 * i)) & 7));
}

/* Output the name of type TYPE, with no punctuation.
   Such names can be set up either by typedef declarations
   or by struct, enum and union tags.  */

static void
dbxout_type_name (type)
     register tree type;
{
  tree t;
  if (TYPE_NAME (type) == 0)
    abort ();
  if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
    {
      t = TYPE_NAME (type);
    }
  else if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL)
    {
      t = DECL_NAME (TYPE_NAME (type));
    }
  else
    abort ();

  fprintf (asmfile, "%s", IDENTIFIER_POINTER (t));
  CHARS (IDENTIFIER_LENGTH (t));
}

/* Output a .stabs for the symbol defined by DECL,
   which must be a ..._DECL node in the normal namespace.
   It may be a CONST_DECL, a FUNCTION_DECL, a PARM_DECL or a VAR_DECL.
   LOCAL is nonzero if the scope is less than the entire file.  */

void
dbxout_symbol (decl, local)
     tree decl;
     int local;
{
  tree type = TREE_TYPE (decl);
  tree context = NULL_TREE;

  /* Cast avoids warning in old compilers.  */
  current_sym_code = (STAB_CODE_TYPE) 0;
  current_sym_value = 0;
  current_sym_addr = 0;

  /* Ignore nameless syms, but don't ignore type tags.  */

  if ((DECL_NAME (decl) == 0 && TREE_CODE (decl) != TYPE_DECL)
      || DECL_IGNORED_P (decl))
    return;

  dbxout_prepare_symbol (decl);

  /* The output will always start with the symbol name,
     so always count that in the length-output-so-far.  */

  if (DECL_NAME (decl) != 0)
    current_sym_nchars = 2 + IDENTIFIER_LENGTH (DECL_NAME (decl));

  switch (TREE_CODE (decl))
    {
    case CONST_DECL:
      /* Enum values are defined by defining the enum type.  */
      break;

    case FUNCTION_DECL:
      if (DECL_RTL (decl) == 0)
	return;
      if (DECL_EXTERNAL (decl))
	break;
      /* Don't mention a nested function under its parent.  */
      context = decl_function_context (decl);
      if (context == current_function_decl)
	break;
      if (GET_CODE (DECL_RTL (decl)) != MEM
	  || GET_CODE (XEXP (DECL_RTL (decl), 0)) != SYMBOL_REF)
	break;
      FORCE_TEXT;

      fprintf (asmfile, "%s \"%s:%c", ASM_STABS_OP,
	       IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)),
	       TREE_PUBLIC (decl) ? 'F' : 'f');

      current_sym_code = N_FUN;
      current_sym_addr = XEXP (DECL_RTL (decl), 0);

      if (TREE_TYPE (type))
	dbxout_type (TREE_TYPE (type), 0, 0);
      else
	dbxout_type (void_type_node, 0, 0);

      /* For a nested function, when that function is compiled,
	 mention the containing function name
	 as well as (since dbx wants it) our own assembler-name.  */
      if (context != 0)
	fprintf (asmfile, ",%s,%s",
		 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)),
		 IDENTIFIER_POINTER (DECL_NAME (context)));

      dbxout_finish_symbol (decl);
      break;

    case TYPE_DECL:
#if 0
      /* This seems all wrong.  Outputting most kinds of types gives no name
	 at all.  A true definition gives no name; a cross-ref for a
	 structure can give the tag name, but not a type name.
	 It seems that no typedef name is defined by outputting a type.  */

      /* If this typedef name was defined by outputting the type,
	 don't duplicate it.  */
      if (typevec[TYPE_SYMTAB_ADDRESS (type)] == TYPE_DEFINED
	  && TYPE_NAME (TREE_TYPE (decl)) == decl)
	return;
#endif
      /* Don't output the same typedef twice.
         And don't output what language-specific stuff doesn't want output.  */
      if (TREE_ASM_WRITTEN (decl) || TYPE_DECL_SUPPRESS_DEBUG (decl))
	return;

      FORCE_TEXT;

      {
	int tag_needed = 1;
	int did_output = 0;

	if (DECL_NAME (decl))
	  {
	    /* Nonzero means we must output a tag as well as a typedef.  */
	    tag_needed = 0;

	    /* Handle the case of a C++ structure or union
	       where the TYPE_NAME is a TYPE_DECL
	       which gives both a typedef name and a tag.  */
	    /* dbx requires the tag first and the typedef second.  */
	    if ((TREE_CODE (type) == RECORD_TYPE
		 || TREE_CODE (type) == UNION_TYPE
		 || TREE_CODE (type) == QUAL_UNION_TYPE)
		&& TYPE_NAME (type) == decl
		&& !(use_gnu_debug_info_extensions && have_used_extensions)
		&& !TREE_ASM_WRITTEN (TYPE_NAME (type))
		/* Distinguish the implicit typedefs of C++
		   from explicit ones that might be found in C.  */
                && (!strcmp (lang_identify (), "cplusplus") 
		    /* The following line maybe unnecessary;
		       in 2.6, try removing it.  */
		    || DECL_SOURCE_LINE (decl) == 0))
	      {
		tree name = TYPE_NAME (type);
		if (TREE_CODE (name) == TYPE_DECL)
		  name = DECL_NAME (name);

		current_sym_code = DBX_TYPE_DECL_STABS_CODE;
		current_sym_value = 0;
		current_sym_addr = 0;
		current_sym_nchars = 2 + IDENTIFIER_LENGTH (name);

		fprintf (asmfile, "%s \"%s:T", ASM_STABS_OP,
			 IDENTIFIER_POINTER (name));
		dbxout_type (type, 1, 0);
		dbxout_finish_symbol (NULL_TREE);
	      }

	    /* Output typedef name.  */
	    fprintf (asmfile, "%s \"%s:", ASM_STABS_OP,
		     IDENTIFIER_POINTER (DECL_NAME (decl)));

	    /* Short cut way to output a tag also.  */
	    if ((TREE_CODE (type) == RECORD_TYPE
		 || TREE_CODE (type) == UNION_TYPE
		 || TREE_CODE (type) == QUAL_UNION_TYPE)
		&& TYPE_NAME (type) == decl)
	      {
		if (use_gnu_debug_info_extensions && have_used_extensions)
		  {
		    putc ('T', asmfile);
		    TREE_ASM_WRITTEN (TYPE_NAME (type)) = 1;
		  }
#if 0 /* Now we generate the tag for this case up above.  */
		else
		  tag_needed = 1;
#endif
	      }

	    putc ('t', asmfile);
	    current_sym_code = DBX_TYPE_DECL_STABS_CODE;

	    dbxout_type (type, 1, 0);
	    dbxout_finish_symbol (decl);
	    did_output = 1;
	  }

	/* Don't output a tag if this is an incomplete type (TYPE_SIZE is
	   zero).  This prevents the sun4 Sun OS 4.x dbx from crashing.  */ 

	if (tag_needed && TYPE_NAME (type) != 0
	    && (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE
		|| (DECL_NAME (TYPE_NAME (type)) != 0))
	    && TYPE_SIZE (type) != 0
	    && !TREE_ASM_WRITTEN (TYPE_NAME (type)))
	  {
	    /* For a TYPE_DECL with no name, but the type has a name,
	       output a tag.
	       This is what represents `struct foo' with no typedef.  */
	    /* In C++, the name of a type is the corresponding typedef.
	       In C, it is an IDENTIFIER_NODE.  */
	    tree name = TYPE_NAME (type);
	    if (TREE_CODE (name) == TYPE_DECL)
	      name = DECL_NAME (name);

	    current_sym_code = DBX_TYPE_DECL_STABS_CODE;
	    current_sym_value = 0;
	    current_sym_addr = 0;
	    current_sym_nchars = 2 + IDENTIFIER_LENGTH (name);

	    fprintf (asmfile, "%s \"%s:T", ASM_STABS_OP,
		     IDENTIFIER_POINTER (name));
	    dbxout_type (type, 1, 0);
	    dbxout_finish_symbol (NULL_TREE);
	    did_output = 1;
	  }

	/* If an enum type has no name, it cannot be referred to,
	   but we must output it anyway, since the enumeration constants
	   can be referred to.  */
	if (!did_output && TREE_CODE (type) == ENUMERAL_TYPE)
	  {
	    current_sym_code = DBX_TYPE_DECL_STABS_CODE;
	    current_sym_value = 0;
	    current_sym_addr = 0;
	    current_sym_nchars = 2;

	    /* Some debuggers fail when given NULL names, so give this a
	       harmless name of ` '.  */
	    fprintf (asmfile, "%s \" :T", ASM_STABS_OP);
	    dbxout_type (type, 1, 0);
	    dbxout_finish_symbol (NULL_TREE);
	  }

	/* Prevent duplicate output of a typedef.  */
	TREE_ASM_WRITTEN (decl) = 1;
	break;
      }