macro.c

/* Part of CPP library.  (Macro and #define handling.)
   Copyright (C) 1986, 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1998,
   1999, 2000, 2001, 2002, 2003, 2004, 2005,
   2006, 2007, 2008, 2009 Free Software Foundation, Inc.
   Written by Per Bothner, 1994.
   Based on CCCP program by Paul Rubin, June 1986
   Adapted to ANSI C, Richard Stallman, Jan 1987

This program 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.

This program 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 this program; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.

 In other words, you are welcome to use, share and improve this program.
 You are forbidden to forbid anyone else to use, share and improve
 what you give them.   Help stamp out software-hoarding!  */

#include "config.h"
#include "system.h"
#include "cpplib.h"
#include "internal.h"

typedef struct macro_arg macro_arg;
struct macro_arg
{
  const cpp_token **first;	/* First token in unexpanded argument.  */
  const cpp_token **expanded;	/* Macro-expanded argument.  */
  const cpp_token *stringified;	/* Stringified argument.  */
  unsigned int count;		/* # of tokens in argument.  */
  unsigned int expanded_count;	/* # of tokens in expanded argument.  */
};

/* Macro expansion.  */

static int enter_macro_context (cpp_reader *, cpp_hashnode *,
				const cpp_token *);
static int builtin_macro (cpp_reader *, cpp_hashnode *);
static void push_ptoken_context (cpp_reader *, cpp_hashnode *, _cpp_buff *,
				 const cpp_token **, unsigned int);
static _cpp_buff *collect_args (cpp_reader *, const cpp_hashnode *,
				_cpp_buff **);
static cpp_context *next_context (cpp_reader *);
static const cpp_token *padding_token (cpp_reader *, const cpp_token *);
static void expand_arg (cpp_reader *, macro_arg *);
static const cpp_token *new_string_token (cpp_reader *, uchar *, unsigned int);
static const cpp_token *stringify_arg (cpp_reader *, macro_arg *);
static void paste_all_tokens (cpp_reader *, const cpp_token *);
static bool paste_tokens (cpp_reader *, const cpp_token **, const cpp_token *);
static void replace_args (cpp_reader *, cpp_hashnode *, cpp_macro *,
			  macro_arg *);
static _cpp_buff *funlike_invocation_p (cpp_reader *, cpp_hashnode *,
					_cpp_buff **);
static bool create_iso_definition (cpp_reader *, cpp_macro *);

/* #define directive parsing and handling.  */

static cpp_token *alloc_expansion_token (cpp_reader *, cpp_macro *);
static cpp_token *lex_expansion_token (cpp_reader *, cpp_macro *);
static bool warn_of_redefinition (cpp_reader *, const cpp_hashnode *,
				  const cpp_macro *);
static bool parse_params (cpp_reader *, cpp_macro *);
static void check_trad_stringification (cpp_reader *, const cpp_macro *,
					const cpp_string *);

/* Emits a warning if NODE is a macro defined in the main file that
   has not been used.  */
int
_cpp_warn_if_unused_macro (cpp_reader *pfile, cpp_hashnode *node,
			   void *v ATTRIBUTE_UNUSED)
{
  if (node->type == NT_MACRO && !(node->flags & NODE_BUILTIN))
    {
      cpp_macro *macro = node->value.macro;

      if (!macro->used
	  && MAIN_FILE_P (linemap_lookup (pfile->line_table, macro->line)))
	cpp_error_with_line (pfile, CPP_DL_WARNING, macro->line, 0,
			     "macro \"%s\" is not used", NODE_NAME (node));
    }

  return 1;
}

/* Allocates and returns a CPP_STRING token, containing TEXT of length
   LEN, after null-terminating it.  TEXT must be in permanent storage.  */
static const cpp_token *
new_string_token (cpp_reader *pfile, unsigned char *text, unsigned int len)
{
  cpp_token *token = _cpp_temp_token (pfile);

  text[len] = '\0';
  token->type = CPP_STRING;
  token->val.str.len = len;
  token->val.str.text = text;
  token->flags = 0;
  return token;
}

static const char * const monthnames[] =
{
  "Jan", "Feb", "Mar", "Apr", "May", "Jun",
  "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};

/* Helper function for builtin_macro.  Returns the text generated by
   a builtin macro. */
const uchar *
_cpp_builtin_macro_text (cpp_reader *pfile, cpp_hashnode *node)
{
  const struct line_map *map;
  const uchar *result = NULL;
  linenum_type number = 1;

  switch (node->value.builtin)
    {
    default:
      cpp_error (pfile, CPP_DL_ICE, "invalid built-in macro \"%s\"",
		 NODE_NAME (node));
      break;

    case BT_TIMESTAMP:
      {
	cpp_buffer *pbuffer = cpp_get_buffer (pfile);
	if (pbuffer->timestamp == NULL)
	  {
	    /* Initialize timestamp value of the assotiated file. */
            struct _cpp_file *file = cpp_get_file (pbuffer);
	    if (file)
	      {
    		/* Generate __TIMESTAMP__ string, that represents 
		   the date and time of the last modification 
		   of the current source file. The string constant 
		   looks like "Sun Sep 16 01:03:52 1973".  */
		struct tm *tb = NULL;
		struct stat *st = _cpp_get_file_stat (file);
		if (st)
		  tb = localtime (&st->st_mtime);
		if (tb)
		  {
		    char *str = asctime (tb);
		    size_t len = strlen (str);
		    unsigned char *buf = _cpp_unaligned_alloc (pfile, len + 2);
		    buf[0] = '"';
		    strcpy ((char *) buf + 1, str);
		    buf[len] = '"';
		    pbuffer->timestamp = buf;
		  }
		else
		  {
		    cpp_errno (pfile, CPP_DL_WARNING,
			"could not determine file timestamp");
		    pbuffer->timestamp = UC"\"??? ??? ?? ??:??:?? ????\"";
		  }
	      }
	  }
	result = pbuffer->timestamp;
      }
      break;
    case BT_FILE:
    case BT_BASE_FILE:
      {
	unsigned int len;
	const char *name;
	uchar *buf;
	map = linemap_lookup (pfile->line_table, pfile->line_table->highest_line);

	if (node->value.builtin == BT_BASE_FILE)
	  while (! MAIN_FILE_P (map))
	    map = INCLUDED_FROM (pfile->line_table, map);

	name = map->to_file;
	len = strlen (name);
	buf = _cpp_unaligned_alloc (pfile, len * 2 + 3);
	result = buf;
	*buf = '"';
	buf = cpp_quote_string (buf + 1, (const unsigned char *) name, len);
	*buf++ = '"';
	*buf = '\0';
      }
      break;

    case BT_INCLUDE_LEVEL:
      /* The line map depth counts the primary source as level 1, but
	 historically __INCLUDE_DEPTH__ has called the primary source
	 level 0.  */
      number = pfile->line_table->depth - 1;
      break;

    case BT_SPECLINE:
      map = &pfile->line_table->maps[pfile->line_table->used-1];
      /* If __LINE__ is embedded in a macro, it must expand to the
	 line of the macro's invocation, not its definition.
	 Otherwise things like assert() will not work properly.  */
      number = SOURCE_LINE (map, 
			    CPP_OPTION (pfile, traditional) 
			    ? pfile->line_table->highest_line
			    : pfile->cur_token[-1].src_loc);
      break;

      /* __STDC__ has the value 1 under normal circumstances.
	 However, if (a) we are in a system header, (b) the option
	 stdc_0_in_system_headers is true (set by target config), and
	 (c) we are not in strictly conforming mode, then it has the
	 value 0.  (b) and (c) are already checked in cpp_init_builtins.  */
    case BT_STDC:
      if (cpp_in_system_header (pfile))
	number = 0;
      else
	number = 1;
      break;

    case BT_DATE:
    case BT_TIME:
      if (pfile->date == NULL)
	{
	  /* Allocate __DATE__ and __TIME__ strings from permanent
	     storage.  We only do this once, and don't generate them
	     at init time, because time() and localtime() are very
	     slow on some systems.  */
	  time_t tt;
	  struct tm *tb = NULL;

	  /* (time_t) -1 is a legitimate value for "number of seconds
	     since the Epoch", so we have to do a little dance to
	     distinguish that from a genuine error.  */
	  errno = 0;
	  tt = time(NULL);
	  if (tt != (time_t)-1 || errno == 0)
	    tb = localtime (&tt);

	  if (tb)
	    {
	      pfile->date = _cpp_unaligned_alloc (pfile,
						  sizeof ("\"Oct 11 1347\""));
	      sprintf ((char *) pfile->date, "\"%s %2d %4d\"",
		       monthnames[tb->tm_mon], tb->tm_mday,
		       tb->tm_year + 1900);

	      pfile->time = _cpp_unaligned_alloc (pfile,
						  sizeof ("\"12:34:56\""));
	      sprintf ((char *) pfile->time, "\"%02d:%02d:%02d\"",
		       tb->tm_hour, tb->tm_min, tb->tm_sec);
	    }
	  else
	    {
	      cpp_errno (pfile, CPP_DL_WARNING,
			 "could not determine date and time");
		
	      pfile->date = UC"\"??? ?? ????\"";
	      pfile->time = UC"\"??:??:??\"";
	    }
	}

      if (node->value.builtin == BT_DATE)
	result = pfile->date;
      else
	result = pfile->time;
      break;

    case BT_COUNTER:
      if (CPP_OPTION (pfile, directives_only) && pfile->state.in_directive)
	cpp_error (pfile, CPP_DL_ERROR,
	    "__COUNTER__ expanded inside directive with -fdirectives-only");
      number = pfile->counter++;
      break;
    }

  if (result == NULL)
    {
      /* 21 bytes holds all NUL-terminated unsigned 64-bit numbers.  */
      result = _cpp_unaligned_alloc (pfile, 21);
      sprintf ((char *) result, "%u", number);
    }

  return result;      
}

/* Convert builtin macros like __FILE__ to a token and push it on the
   context stack.  Also handles _Pragma, for which a new token may not
   be created.  Returns 1 if it generates a new token context, 0 to
   return the token to the caller.  */
static int
builtin_macro (cpp_reader *pfile, cpp_hashnode *node)
{
  const uchar *buf;
  size_t len;
  char *nbuf;

  if (node->value.builtin == BT_PRAGMA)
    {
      /* Don't interpret _Pragma within directives.  The standard is
         not clear on this, but to me this makes most sense.  */
      if (pfile->state.in_directive)
	return 0;

      return _cpp_do__Pragma (pfile);
    }

  buf = _cpp_builtin_macro_text (pfile, node);
  len = ustrlen (buf);
  nbuf = (char *) alloca (len + 1);
  memcpy (nbuf, buf, len);
  nbuf[len]='\n';

  cpp_push_buffer (pfile, (uchar *) nbuf, len, /* from_stage3 */ true);
  _cpp_clean_line (pfile);

  /* Set pfile->cur_token as required by _cpp_lex_direct.  */
  pfile->cur_token = _cpp_temp_token (pfile);
  _cpp_push_token_context (pfile, NULL, _cpp_lex_direct (pfile), 1);
  if (pfile->buffer->cur != pfile->buffer->rlimit)
    cpp_error (pfile, CPP_DL_ICE, "invalid built-in macro \"%s\"",
	       NODE_NAME (node));
  _cpp_pop_buffer (pfile);

  return 1;
}

/* Copies SRC, of length LEN, to DEST, adding backslashes before all
   backslashes and double quotes. DEST must be of sufficient size.
   Returns a pointer to the end of the string.  */
uchar *
cpp_quote_string (uchar *dest, const uchar *src, unsigned int len)
{
  while (len--)
    {
      uchar c = *src++;

      if (c == '\\' || c == '"')
	{
	  *dest++ = '\\';
	  *dest++ = c;
	}
      else
	  *dest++ = c;
    }

  return dest;
}

/* Convert a token sequence ARG to a single string token according to
   the rules of the ISO C #-operator.  */
static const cpp_token *
stringify_arg (cpp_reader *pfile, macro_arg *arg)
{
  unsigned char *dest;
  unsigned int i, escape_it, backslash_count = 0;
  const cpp_token *source = NULL;
  size_t len;

  if (BUFF_ROOM (pfile->u_buff) < 3)
    _cpp_extend_buff (pfile, &pfile->u_buff, 3);
  dest = BUFF_FRONT (pfile->u_buff);
  *dest++ = '"';

  /* Loop, reading in the argument's tokens.  */
  for (i = 0; i < arg->count; i++)
    {
      const cpp_token *token = arg->first[i];

      if (token->type == CPP_PADDING)
	{
	  if (source == NULL)
	    source = token->val.source;
	  continue;
	}

      escape_it = (token->type == CPP_STRING || token->type == CPP_CHAR
		   || token->type == CPP_WSTRING || token->type == CPP_STRING
		   || token->type == CPP_STRING32 || token->type == CPP_CHAR32
		   || token->type == CPP_STRING16 || token->type == CPP_CHAR16);

      /* Room for each char being written in octal, initial space and
	 final quote and NUL.  */
      len = cpp_token_len (token);
      if (escape_it)
	len *= 4;
      len += 3;

      if ((size_t) (BUFF_LIMIT (pfile->u_buff) - dest) < len)
	{
	  size_t len_so_far = dest - BUFF_FRONT (pfile->u_buff);
	  _cpp_extend_buff (pfile, &pfile->u_buff, len);
	  dest = BUFF_FRONT (pfile->u_buff) + len_so_far;
	}

      /* Leading white space?  */
      if (dest - 1 != BUFF_FRONT (pfile->u_buff))
	{
	  if (source == NULL)
	    source = token;
	  if (source->flags & PREV_WHITE)
	    *dest++ = ' ';
	}
      source = NULL;

      if (escape_it)
	{
	  _cpp_buff *buff = _cpp_get_buff (pfile, len);
	  unsigned char *buf = BUFF_FRONT (buff);
	  len = cpp_spell_token (pfile, token, buf, true) - buf;
	  dest = cpp_quote_string (dest, buf, len);
	  _cpp_release_buff (pfile, buff);
	}
      else
	dest = cpp_spell_token (pfile, token, dest, true);

      if (token->type == CPP_OTHER && token->val.str.text[0] == '\\')
	backslash_count++;
      else
	backslash_count = 0;
    }

  /* Ignore the final \ of invalid string literals.  */
  if (backslash_count & 1)
    {
      cpp_error (pfile, CPP_DL_WARNING,
		 "invalid string literal, ignoring final '\\'");
      dest--;
    }

  /* Commit the memory, including NUL, and return the token.  */
  *dest++ = '"';
  len = dest - BUFF_FRONT (pfile->u_buff);
  BUFF_FRONT (pfile->u_buff) = dest + 1;
  return new_string_token (pfile, dest - len, len);
}

/* Try to paste two tokens.  On success, return nonzero.  In any
   case, PLHS is updated to point to the pasted token, which is
   guaranteed to not have the PASTE_LEFT flag set.  */
static bool
paste_tokens (cpp_reader *pfile, const cpp_token **plhs, const cpp_token *rhs)
{
  unsigned char *buf, *end, *lhsend;
  cpp_token *lhs;
  unsigned int len;

  len = cpp_token_len (*plhs) + cpp_token_len (rhs) + 1;
  buf = (unsigned char *) alloca (len);
  end = lhsend = cpp_spell_token (pfile, *plhs, buf, false);

  /* Avoid comment headers, since they are still processed in stage 3.
     It is simpler to insert a space here, rather than modifying the
     lexer to ignore comments in some circumstances.  Simply returning
     false doesn't work, since we want to clear the PASTE_LEFT flag.  */
  if ((*plhs)->type == CPP_DIV && rhs->type != CPP_EQ)
    *end++ = ' ';
  /* In one obscure case we might see padding here.  */
  if (rhs->type != CPP_PADDING)
    end = cpp_spell_token (pfile, rhs, end, false);
  *end = '\n';

  cpp_push_buffer (pfile, buf, end - buf, /* from_stage3 */ true);
  _cpp_clean_line (pfile);

  /* Set pfile->cur_token as required by _cpp_lex_direct.  */
  pfile->cur_token = _cpp_temp_token (pfile);
  lhs = _cpp_lex_direct (pfile);
  if (pfile->buffer->cur != pfile->buffer->rlimit)
    {
      source_location saved_loc = lhs->src_loc;

      _cpp_pop_buffer (pfile);
      _cpp_backup_tokens (pfile, 1);
      *lhsend = '\0';

      /* We have to remove the PASTE_LEFT flag from the old lhs, but
	 we want to keep the new location.  */
      *lhs = **plhs;
      *plhs = lhs;
      lhs->src_loc = saved_loc;
      lhs->flags &= ~PASTE_LEFT;

      /* Mandatory error for all apart from assembler.  */
      if (CPP_OPTION (pfile, lang) != CLK_ASM)
	cpp_error (pfile, CPP_DL_ERROR,
	 "pasting \"%s\" and \"%s\" does not give a valid preprocessing token",
		   buf, cpp_token_as_text (pfile, rhs));
      return false;
    }

  *plhs = lhs;
  _cpp_pop_buffer (pfile);
  return true;
}

/* Handles an arbitrarily long sequence of ## operators, with initial
   operand LHS.  This implementation is left-associative,
   non-recursive, and finishes a paste before handling succeeding
   ones.  If a paste fails, we back up to the RHS of the failing ##
   operator before pushing the context containing the result of prior
   successful pastes, with the effect that the RHS appears in the
   output stream after the pasted LHS normally.  */
static void
paste_all_tokens (cpp_reader *pfile, const cpp_token *lhs)
{
  const cpp_token *rhs;
  cpp_context *context = pfile->context;

  do
    {
      /* Take the token directly from the current context.  We can do
	 this, because we are in the replacement list of either an
	 object-like macro, or a function-like macro with arguments
	 inserted.  In either case, the constraints to #define
	 guarantee we have at least one more token.  */
      if (context->direct_p)
	rhs = FIRST (context).token++;
      else
	rhs = *FIRST (context).ptoken++;

      if (rhs->type == CPP_PADDING)
	{
	  if (rhs->flags & PASTE_LEFT)
	    abort ();
	}
      if (!paste_tokens (pfile, &lhs, rhs))
	break;
    }
  while (rhs->flags & PASTE_LEFT);

  /* Put the resulting token in its own context.  */
  _cpp_push_token_context (pfile, NULL, lhs, 1);
}

/* Returns TRUE if the number of arguments ARGC supplied in an
   invocation of the MACRO referenced by NODE is valid.  An empty
   invocation to a macro with no parameters should pass ARGC as zero.

   Note that MACRO cannot necessarily be deduced from NODE, in case
   NODE was redefined whilst collecting arguments.  */
bool
_cpp_arguments_ok (cpp_reader *pfile, cpp_macro *macro, const cpp_hashnode *node, unsigned int argc)
{
  if (argc == macro->paramc)
    return true;

  if (argc < macro->paramc)
    {
      /* As an extension, a rest argument is allowed to not appear in
	 the invocation at all.
	 e.g. #define debug(format, args...) something
	 debug("string");

	 This is exactly the same as if there had been an empty rest
	 argument - debug("string", ).  */

      if (argc + 1 == macro->paramc && macro->variadic)
	{
	  if (CPP_PEDANTIC (pfile) && ! macro->syshdr)
	    cpp_error (pfile, CPP_DL_PEDWARN,
		       "ISO C99 requires rest arguments to be used");
	  return true;
	}

      cpp_error (pfile, CPP_DL_ERROR,
		 "macro \"%s\" requires %u arguments, but only %u given",
		 NODE_NAME (node), macro->paramc, argc);
    }
  else
    cpp_error (pfile, CPP_DL_ERROR,
	       "macro \"%s\" passed %u arguments, but takes just %u",
	       NODE_NAME (node), argc, macro->paramc);

  return false;
}

/* Reads and returns the arguments to a function-like macro
   invocation.  Assumes the opening parenthesis has been processed.
   If there is an error, emits an appropriate diagnostic and returns
   NULL.  Each argument is terminated by a CPP_EOF token, for the
   future benefit of expand_arg().  If there are any deferred
   #pragma directives among macro arguments, store pointers to the
   CPP_PRAGMA ... CPP_PRAGMA_EOL tokens into *PRAGMA_BUFF buffer.  */
static _cpp_buff *
collect_args (cpp_reader *pfile, const cpp_hashnode *node,
	      _cpp_buff **pragma_buff)
{
  _cpp_buff *buff, *base_buff;
  cpp_macro *macro;
  macro_arg *args, *arg;
  const cpp_token *token;
  unsigned int argc;

  macro = node->value.macro;
  if (macro->paramc)
    argc = macro->paramc;
  else
    argc = 1;
  buff = _cpp_get_buff (pfile, argc * (50 * sizeof (cpp_token *)
				       + sizeof (macro_arg)));
  base_buff = buff;
  args = (macro_arg *) buff->base;
  memset (args, 0, argc * sizeof (macro_arg));
  buff->cur = (unsigned char *) &args[argc];
  arg = args, argc = 0;

  /* Collect the tokens making up each argument.  We don't yet know
     how many arguments have been supplied, whether too many or too
     few.  Hence the slightly bizarre usage of "argc" and "arg".  */
  do
    {
      unsigned int paren_depth = 0;
      unsigned int ntokens = 0;

      argc++;
      arg->first = (const cpp_token **) buff->cur;

      for (;;)
	{
	  /* Require space for 2 new tokens (including a CPP_EOF).  */
	  if ((unsigned char *) &arg->first[ntokens + 2] > buff->limit)
	    {
	      buff = _cpp_append_extend_buff (pfile, buff,
					      1000 * sizeof (cpp_token *));
	      arg->first = (const cpp_token **) buff->cur;
	    }

	  token = cpp_get_token (pfile);

	  if (token->type == CPP_PADDING)
	    {
	      /* Drop leading padding.  */
	      if (ntokens == 0)
		continue;
	    }
	  else if (token->type == CPP_OPEN_PAREN)
	    paren_depth++;
	  else if (token->type == CPP_CLOSE_PAREN)
	    {
	      if (paren_depth-- == 0)
		break;
	    }
	  else if (token->type == CPP_COMMA)
	    {
	      /* A comma does not terminate an argument within
		 parentheses or as part of a variable argument.  */
	      if (paren_depth == 0
		  && ! (macro->variadic && argc == macro->paramc))
		break;
	    }
	  else if (token->type == CPP_EOF
		   || (token->type == CPP_HASH && token->flags & BOL))
	    break;
	  else if (token->type == CPP_PRAGMA)
	    {
	      cpp_token *newtok = _cpp_temp_token (pfile);

	      /* CPP_PRAGMA token lives in directive_result, which will
		 be overwritten on the next directive.  */
	      *newtok = *token;
	      token = newtok;
	      do
		{
		  if (*pragma_buff == NULL
		      || BUFF_ROOM (*pragma_buff) < sizeof (cpp_token *))
		    {
		      _cpp_buff *next;
		      if (*pragma_buff == NULL)
			*pragma_buff
			  = _cpp_get_buff (pfile, 32 * sizeof (cpp_token *));
		      else
			{
			  next = *pragma_buff;
			  *pragma_buff
			    = _cpp_get_buff (pfile,
					     (BUFF_FRONT (*pragma_buff)
					      - (*pragma_buff)->base) * 2);
			  (*pragma_buff)->next = next;
			}
		    }
		  *(const cpp_token **) BUFF_FRONT (*pragma_buff) = token;
		  BUFF_FRONT (*pragma_buff) += sizeof (cpp_token *);
		  if (token->type == CPP_PRAGMA_EOL)
		    break;
		  token = cpp_get_token (pfile);
		}
	      while (token->type != CPP_EOF);

	      /* In deferred pragmas parsing_args and prevent_expansion
		 had been changed, reset it.  */
	      pfile->state.parsing_args = 2;
	      pfile->state.prevent_expansion = 1;

	      if (token->type == CPP_EOF)
		break;
	      else
		continue;
	    }

	  arg->first[ntokens++] = token;
	}

      /* Drop trailing padding.  */
      while (ntokens > 0 && arg->first[ntokens - 1]->type == CPP_PADDING)
	ntokens--;

      arg->count = ntokens;
      arg->first[ntokens] = &pfile->eof;

      /* Terminate the argument.  Excess arguments loop back and
	 overwrite the final legitimate argument, before failing.  */
      if (argc <= macro->paramc)
	{
	  buff->cur = (unsigned char *) &arg->first[ntokens + 1];
	  if (argc != macro->paramc)
	    arg++;
	}
    }
  while (token->type != CPP_CLOSE_PAREN && token->type != CPP_EOF);

  if (token->type == CPP_EOF)
    {
      /* We still need the CPP_EOF to end directives, and to end
	 pre-expansion of a macro argument.  Step back is not
	 unconditional, since we don't want to return a CPP_EOF to our
	 callers at the end of an -include-d file.  */
      if (pfile->context->prev || pfile->state.in_directive)
	_cpp_backup_tokens (pfile, 1);
      cpp_error (pfile, CPP_DL_ERROR,
		 "unterminated argument list invoking macro \"%s\"",
		 NODE_NAME (node));
    }
  else
    {
      /* A single empty argument is counted as no argument.  */
      if (argc == 1 && macro->paramc == 0 && args[0].count == 0)
	argc = 0;
      if (_cpp_arguments_ok (pfile, macro, node, argc))
	{
	  /* GCC has special semantics for , ## b where b is a varargs
	     parameter: we remove the comma if b was omitted entirely.
	     If b was merely an empty argument, the comma is retained.
	     If the macro takes just one (varargs) parameter, then we
	     retain the comma only if we are standards conforming.

	     If FIRST is NULL replace_args () swallows the comma.  */
	  if (macro->variadic && (argc < macro->paramc
				  || (argc == 1 && args[0].count == 0
				      && !CPP_OPTION (pfile, std))))
	    args[macro->paramc - 1].first = NULL;
	  return base_buff;
	}
    }

  /* An error occurred.  */
  _cpp_release_buff (pfile, base_buff);
  return NULL;
}

/* Search for an opening parenthesis to the macro of NODE, in such a
   way that, if none is found, we don't lose the information in any
   intervening padding tokens.  If we find the parenthesis, collect
   the arguments and return the buffer containing them.  PRAGMA_BUFF
   argument is the same as in collect_args.  */
static _cpp_buff *
funlike_invocation_p (cpp_reader *pfile, cpp_hashnode *node,
		      _cpp_buff **pragma_buff)
{
  const cpp_token *token, *padding = NULL;

  for (;;)
    {
      token = cpp_get_token (pfile);
      if (token->type != CPP_PADDING)
	break;
      if (padding == NULL
	  || (!(padding->flags & PREV_WHITE) && token->val.source == NULL))
	padding = token;
    }

  if (token->type == CPP_OPEN_PAREN)
    {
      pfile->state.parsing_args = 2;
      return collect_args (pfile, node, pragma_buff);
    }

  /* CPP_EOF can be the end of macro arguments, or the end of the
     file.  We mustn't back up over the latter.  Ugh.  */
  if (token->type != CPP_EOF || token == &pfile->eof)
    {
      /* Back up.  We may have skipped padding, in which case backing
	 up more than one token when expanding macros is in general
	 too difficult.  We re-insert it in its own context.  */
      _cpp_backup_tokens (pfile, 1);
      if (padding)
	_cpp_push_token_context (pfile, NULL, padding, 1);
    }

  return NULL;
}

/* Push the context of a macro with hash entry NODE onto the context
   stack.  If we can successfully expand the macro, we push a context
   containing its yet-to-be-rescanned replacement list and return one.
   If there were additionally any unexpanded deferred #pragma directives
   among macro arguments, push another context containing the
   pragma tokens before the yet-to-be-rescanned replacement list
   and return two.  Otherwise, we don't push a context and return zero.  */
static int
enter_macro_context (cpp_reader *pfile, cpp_hashnode *node,
		     const cpp_token *result)
{
  /* The presence of a macro invalidates a file's controlling macro.  */
  pfile->mi_valid = false;

  pfile->state.angled_headers = false;

  if ((node->flags & NODE_BUILTIN) && !(node->flags & NODE_USED))
    {
      node->flags |= NODE_USED;
      if (pfile->cb.used_define)
	pfile->cb.used_define (pfile, pfile->directive_line, node);
    }

  /* Handle standard macros.  */
  if (! (node->flags & NODE_BUILTIN))
    {
      cpp_macro *macro = node->value.macro;
      _cpp_buff *pragma_buff = NULL;

      if (macro->fun_like)
	{
	  _cpp_buff *buff;

	  pfile->state.prevent_expansion++;
	  pfile->keep_tokens++;
	  pfile->state.parsing_args = 1;
	  buff = funlike_invocation_p (pfile, node, &pragma_buff);
	  pfile->state.parsing_args = 0;
	  pfile->keep_tokens--;
	  pfile->state.prevent_expansion--;

	  if (buff == NULL)
	    {
	      if (CPP_WTRADITIONAL (pfile) && ! node->value.macro->syshdr)
		cpp_error (pfile, CPP_DL_WARNING,
 "function-like macro \"%s\" must be used with arguments in traditional C",
			   NODE_NAME (node));

	      if (pragma_buff)
		_cpp_release_buff (pfile, pragma_buff);

	      return 0;
	    }

	  if (macro->paramc > 0)
	    replace_args (pfile, node, macro, (macro_arg *) buff->base);
	  _cpp_release_buff (pfile, buff);
	}

      /* Disable the macro within its expansion.  */
      node->flags |= NODE_DISABLED;

      if (!(node->flags & NODE_USED))
	{
	  node->flags |= NODE_USED;
	  if (pfile->cb.used_define)
	    pfile->cb.used_define (pfile, pfile->directive_line, node);
	}

      macro->used = 1;

      if (macro->paramc == 0)
	_cpp_push_token_context (pfile, node, macro->exp.tokens, macro->count);

      if (pragma_buff)
	{
	  if (!pfile->state.in_directive)
	    _cpp_push_token_context (pfile, NULL,
				     padding_token (pfile, result), 1);
	  do
	    {
	      _cpp_buff *tail = pragma_buff->next;
	      pragma_buff->next = NULL;
	      push_ptoken_context (pfile, NULL, pragma_buff,
				   (const cpp_token **) pragma_buff->base,
				   ((const cpp_token **) BUFF_FRONT (pragma_buff)
				    - (const cpp_token **) pragma_buff->base));
	      pragma_buff = tail;
	    }
	  while (pragma_buff != NULL);
	  return 2;
	}

      return 1;
    }

  /* Handle built-in macros and the _Pragma operator.  */
  return builtin_macro (pfile, node);
}

/* Replace the parameters in a function-like macro of NODE with the
   actual ARGS, and place the result in a newly pushed token context.
   Expand each argument before replacing, unless it is operated upon
   by the # or ## operators.  */
static void
replace_args (cpp_reader *pfile, cpp_hashnode *node, cpp_macro *macro, macro_arg *args)
{
  unsigned int i, total;
  const cpp_token *src, *limit;
  const cpp_token **dest, **first;
  macro_arg *arg;
  _cpp_buff *buff;

  /* First, fully macro-expand arguments, calculating the number of
     tokens in the final expansion as we go.  The ordering of the if
     statements below is subtle; we must handle stringification before
     pasting.  */
  total = macro->count;
  limit = macro->exp.tokens + macro->count;

  for (src = macro->exp.tokens; src < limit; src++)
    if (src->type == CPP_MACRO_ARG)
      {
	/* Leading and trailing padding tokens.  */
	total += 2;

	/* We have an argument.  If it is not being stringified or
	   pasted it is macro-replaced before insertion.  */
	arg = &args[src->val.arg_no - 1];

	if (src->flags & STRINGIFY_ARG)
	  {
	    if (!arg->stringified)
	      arg->stringified = stringify_arg (pfile, arg);
	  }
	else if ((src->flags & PASTE_LEFT)
		 || (src > macro->exp.tokens && (src[-1].flags & PASTE_LEFT)))
	  total += arg->count - 1;
	else
	  {
	    if (!arg->expanded)
	      expand_arg (pfile, arg);
	    total += arg->expanded_count - 1;
	  }
      }

  /* Now allocate space for the expansion, copy the tokens and replace
     the arguments.  */
  buff = _cpp_get_buff (pfile, total * sizeof (cpp_token *));
  first = (const cpp_token **) buff->base;
  dest = first;

  for (src = macro->exp.tokens; src < limit; src++)
    {
      unsigned int count;
      const cpp_token **from, **paste_flag;

      if (src->type != CPP_MACRO_ARG)
	{
	  *dest++ = src;
	  continue;
	}

      paste_flag = 0;
      arg = &args[src->val.arg_no - 1];
      if (src->flags & STRINGIFY_ARG)
	count = 1, from = &arg->stringified;
      else if (src->flags & PASTE_LEFT)
	count = arg->count, from = arg->first;
      else if (src != macro->exp.tokens && (src[-1].flags & PASTE_LEFT))
	{
	  count = arg->count, from = arg->first;
	  if (dest != first)
	    {
	      if (dest[-1]->type == CPP_COMMA
		  && macro->variadic
		  && src->val.arg_no == macro->paramc)
		{
		  /* Swallow a pasted comma if from == NULL, otherwise
		     drop the paste flag.  */
		  if (from == NULL)
		    dest--;
		  else
		    paste_flag = dest - 1;
		}
	      /* Remove the paste flag if the RHS is a placemarker.  */
	      else if (count == 0)
		paste_flag = dest - 1;
	    }
	}
      else
	count = arg->expanded_count, from = arg->expanded;

      /* Padding on the left of an argument (unless RHS of ##).  */
      if ((!pfile->state.in_directive || pfile->state.directive_wants_padding)
	  && src != macro->exp.tokens && !(src[-1].flags & PASTE_LEFT))
	*dest++ = padding_token (pfile, src);