path: root/gcc/cppinit.c

/* CPP Library.
   Copyright (C) 1986, 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
   Contributed by Per Bothner, 1994-95.
   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 2, 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; if not, write to the Free Software
Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "cpplib.h"
#include "cpphash.h"
#include "intl.h"
#include "mkdeps.h"

/* Internal structures and prototypes.  */

/* A `struct pending_option' remembers one -D, -A, -U, -include, or
   -imacros switch.  */
typedef void (* cl_directive_handler) PARAMS ((cpp_reader *, const char *));
struct pending_option
{
  struct pending_option *next;
  const char *arg;
  cl_directive_handler handler;
};

/* The `pending' structure accumulates all the options that are not
   actually processed until we hit cpp_read_main_file.  It consists of
   several lists, one for each type of option.  We keep both head and
   tail pointers for quick insertion.  */
struct cpp_pending
{
  struct pending_option *directive_head, *directive_tail;
  struct pending_option *imacros_head, *imacros_tail;
  struct pending_option *include_head, *include_tail;
};

#ifdef __STDC__
#define APPEND(pend, list, elt) \
  do {  if (!(pend)->list##_head) (pend)->list##_head = (elt); \
	else (pend)->list##_tail->next = (elt); \
	(pend)->list##_tail = (elt); \
  } while (0)
#else
#define APPEND(pend, list, elt) \
  do {  if (!(pend)->list/**/_head) (pend)->list/**/_head = (elt); \
	else (pend)->list/**/_tail->next = (elt); \
	(pend)->list/**/_tail = (elt); \
  } while (0)
#endif

static void init_library		PARAMS ((void));
static void init_builtins		PARAMS ((cpp_reader *));
static void mark_named_operators	PARAMS ((cpp_reader *));
static bool push_include		PARAMS ((cpp_reader *,
						 struct pending_option *));
static void free_chain			PARAMS ((struct pending_option *));
static void read_original_filename	PARAMS ((cpp_reader *));
static void new_pending_directive	PARAMS ((struct cpp_pending *,
						 const char *,
						 cl_directive_handler));
static int parse_option			PARAMS ((const char *));
static void post_options		PARAMS ((cpp_reader *));

/* If we have designated initializers (GCC >2.7) these tables can be
   initialized, constant data.  Otherwise, they have to be filled in at
   runtime.  */
#if HAVE_DESIGNATED_INITIALIZERS

#define init_trigraph_map()  /* Nothing.  */
#define TRIGRAPH_MAP \
__extension__ const uchar _cpp_trigraph_map[UCHAR_MAX + 1] = {

#define END };
#define s(p, v) [p] = v,

#else

#define TRIGRAPH_MAP uchar _cpp_trigraph_map[UCHAR_MAX + 1] = { 0 }; \
 static void init_trigraph_map PARAMS ((void)) { \
 unsigned char *x = _cpp_trigraph_map;

#define END }
#define s(p, v) x[p] = v;

#endif

TRIGRAPH_MAP
  s('=', '#')	s(')', ']')	s('!', '|')
  s('(', '[')	s('\'', '^')	s('>', '}')
  s('/', '\\')	s('<', '{')	s('-', '~')
END

#undef s
#undef END
#undef TRIGRAPH_MAP

/* A set of booleans indicating what CPP features each source language
   requires.  */
struct lang_flags
{
  char c99;
  char cplusplus;
  char extended_numbers;
  char std;
  char dollars_in_ident;
  char cplusplus_comments;
  char digraphs;
};

/* ??? Enable $ in identifiers in assembly? */
static const struct lang_flags lang_defaults[] =
{ /*              c99 c++ xnum std dollar c++comm digr  */
  /* GNUC89 */  { 0,  0,  1,   0,   1,     1,      1     },
  /* GNUC99 */  { 1,  0,  1,   0,   1,     1,      1     },
  /* STDC89 */  { 0,  0,  0,   1,   0,     0,      0     },
  /* STDC94 */  { 0,  0,  0,   1,   0,     0,      1     },
  /* STDC99 */  { 1,  0,  1,   1,   0,     1,      1     },
  /* GNUCXX */  { 0,  1,  1,   0,   1,     1,      1     },
  /* CXX98  */  { 0,  1,  1,   1,   0,     1,      1     },
  /* ASM    */  { 0,  0,  1,   0,   0,     1,      0     }
};

/* Sets internal flags correctly for a given language.  */
void
cpp_set_lang (pfile, lang)
     cpp_reader *pfile;
     enum c_lang lang;
{
  const struct lang_flags *l = &lang_defaults[(int) lang];

  CPP_OPTION (pfile, lang) = lang;

  CPP_OPTION (pfile, c99)		 = l->c99;
  CPP_OPTION (pfile, cplusplus)		 = l->cplusplus;
  CPP_OPTION (pfile, extended_numbers)	 = l->extended_numbers;
  CPP_OPTION (pfile, std)		 = l->std;
  CPP_OPTION (pfile, trigraphs)		 = l->std;
  CPP_OPTION (pfile, dollars_in_ident)	 = l->dollars_in_ident;
  CPP_OPTION (pfile, cplusplus_comments) = l->cplusplus_comments;
  CPP_OPTION (pfile, digraphs)		 = l->digraphs;
}

#ifdef HOST_EBCDIC
static int opt_comp PARAMS ((const void *, const void *));

/* Run-time sorting of options array.  */
static int
opt_comp (p1, p2)
     const void *p1, *p2;
{
  return strcmp (((struct cl_option *) p1)->opt_text,
		 ((struct cl_option *) p2)->opt_text);
}
#endif

/* init initializes library global state.  It might not need to
   do anything depending on the platform and compiler.  */
static void
init_library ()
{
  static int initialized = 0;

  if (! initialized)
    {
      initialized = 1;

#ifdef HOST_EBCDIC
      /* For non-ASCII hosts, the cl_options array needs to be sorted at
	 runtime.  */
      qsort (cl_options, N_OPTS, sizeof (struct cl_option), opt_comp);
#endif

      /* Set up the trigraph map.  This doesn't need to do anything if
	 we were compiled with a compiler that supports C99 designated
	 initializers.  */
      init_trigraph_map ();

      _cpp_init_mbchar ();
    }
}

/* Initialize a cpp_reader structure.  */
cpp_reader *
cpp_create_reader (lang)
     enum c_lang lang;
{
  cpp_reader *pfile;

  /* Initialize this instance of the library if it hasn't been already.  */
  init_library ();

  pfile = (cpp_reader *) xcalloc (1, sizeof (cpp_reader));

  cpp_set_lang (pfile, lang);
  CPP_OPTION (pfile, warn_import) = 1;
  CPP_OPTION (pfile, warn_multichar) = 1;
  CPP_OPTION (pfile, discard_comments) = 1;
  CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
  CPP_OPTION (pfile, show_column) = 1;
  CPP_OPTION (pfile, tabstop) = 8;
  CPP_OPTION (pfile, operator_names) = 1;
  CPP_OPTION (pfile, warn_endif_labels) = 1;
  CPP_OPTION (pfile, warn_deprecated) = 1;
  CPP_OPTION (pfile, warn_long_long) = !CPP_OPTION (pfile, c99);

  CPP_OPTION (pfile, pending) =
    (struct cpp_pending *) xcalloc (1, sizeof (struct cpp_pending));

  /* Default CPP arithmetic to something sensible for the host for the
     benefit of dumb users like fix-header.  */
  CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
  CPP_OPTION (pfile, char_precision) = CHAR_BIT;
  CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
  CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
  CPP_OPTION (pfile, unsigned_char) = 0;
  CPP_OPTION (pfile, unsigned_wchar) = 1;

  /* Initialize the line map.  Start at logical line 1, so we can use
     a line number of zero for special states.  */
  init_line_maps (&pfile->line_maps);
  pfile->line = 1;

  /* Initialize lexer state.  */
  pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);

  /* Set up static tokens.  */
  pfile->avoid_paste.type = CPP_PADDING;
  pfile->avoid_paste.val.source = NULL;
  pfile->eof.type = CPP_EOF;
  pfile->eof.flags = 0;

  /* Create a token buffer for the lexer.  */
  _cpp_init_tokenrun (&pfile->base_run, 250);
  pfile->cur_run = &pfile->base_run;
  pfile->cur_token = pfile->base_run.base;

  /* Initialize the base context.  */
  pfile->context = &pfile->base_context;
  pfile->base_context.macro = 0;
  pfile->base_context.prev = pfile->base_context.next = 0;

  /* Aligned and unaligned storage.  */
  pfile->a_buff = _cpp_get_buff (pfile, 0);
  pfile->u_buff = _cpp_get_buff (pfile, 0);

  /* The expression parser stack.  */
  _cpp_expand_op_stack (pfile);

  /* Initialize the buffer obstack.  */
  gcc_obstack_init (&pfile->buffer_ob);

  _cpp_init_includes (pfile);

  return pfile;
}

/* Free resources used by PFILE.  Accessing PFILE after this function
   returns leads to undefined behavior.  Returns the error count.  */
void
cpp_destroy (pfile)
     cpp_reader *pfile;
{
  cpp_context *context, *contextn;
  tokenrun *run, *runn;

  free_chain (CPP_OPTION (pfile, pending)->include_head);
  free (CPP_OPTION (pfile, pending));
  free (pfile->op_stack);

  while (CPP_BUFFER (pfile) != NULL)
    _cpp_pop_buffer (pfile);

  if (pfile->out.base)
    free (pfile->out.base);

  if (pfile->macro_buffer)
    {
      free ((PTR) pfile->macro_buffer);
      pfile->macro_buffer = NULL;
      pfile->macro_buffer_len = 0;
    }

  if (pfile->deps)
    deps_free (pfile->deps);
  obstack_free (&pfile->buffer_ob, 0);

  _cpp_destroy_hashtable (pfile);
  _cpp_cleanup_includes (pfile);

  _cpp_free_buff (pfile->a_buff);
  _cpp_free_buff (pfile->u_buff);
  _cpp_free_buff (pfile->free_buffs);

  for (run = &pfile->base_run; run; run = runn)
    {
      runn = run->next;
      free (run->base);
      if (run != &pfile->base_run)
	free (run);
    }

  for (context = pfile->base_context.next; context; context = contextn)
    {
      contextn = context->next;
      free (context);
    }

  free_line_maps (&pfile->line_maps);
  free (pfile);
}

/* This structure defines one built-in identifier.  A node will be
   entered in the hash table under the name NAME, with value VALUE.

   There are two tables of these.  builtin_array holds all the
   "builtin" macros: these are handled by builtin_macro() in
   cppmacro.c.  Builtin is somewhat of a misnomer -- the property of
   interest is that these macros require special code to compute their
   expansions.  The value is a "builtin_type" enumerator.

   operator_array holds the C++ named operators.  These are keywords
   which act as aliases for punctuators.  In C++, they cannot be
   altered through #define, and #if recognizes them as operators.  In
   C, these are not entered into the hash table at all (but see
   <iso646.h>).  The value is a token-type enumerator.  */
struct builtin
{
  const uchar *name;
  unsigned short len;
  unsigned short value;
};

#define B(n, t)    { DSC(n), t }
static const struct builtin builtin_array[] =
{
  B("__TIME__",		 BT_TIME),
  B("__DATE__",		 BT_DATE),
  B("__FILE__",		 BT_FILE),
  B("__BASE_FILE__",	 BT_BASE_FILE),
  B("__LINE__",		 BT_SPECLINE),
  B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL),
  /* Keep builtins not used for -traditional-cpp at the end, and
     update init_builtins() if any more are added.  */
  B("_Pragma",		 BT_PRAGMA),
  B("__STDC__",		 BT_STDC),
};

static const struct builtin operator_array[] =
{
  B("and",	CPP_AND_AND),
  B("and_eq",	CPP_AND_EQ),
  B("bitand",	CPP_AND),
  B("bitor",	CPP_OR),
  B("compl",	CPP_COMPL),
  B("not",	CPP_NOT),
  B("not_eq",	CPP_NOT_EQ),
  B("or",	CPP_OR_OR),
  B("or_eq",	CPP_OR_EQ),
  B("xor",	CPP_XOR),
  B("xor_eq",	CPP_XOR_EQ)
};
#undef B

/* Mark the C++ named operators in the hash table.  */
static void
mark_named_operators (pfile)
     cpp_reader *pfile;
{
  const struct builtin *b;

  for (b = operator_array;
       b < (operator_array + ARRAY_SIZE (operator_array));
       b++)
    {
      cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
      hp->flags |= NODE_OPERATOR;
      hp->is_directive = 0;
      hp->directive_index = b->value;
    }
}

/* Subroutine of cpp_read_main_file; reads the builtins table above and
   enters them, and language-specific macros, into the hash table.  */
static void
init_builtins (pfile)
     cpp_reader *pfile;
{
  const struct builtin *b;
  size_t n = ARRAY_SIZE (builtin_array);

  if (CPP_OPTION (pfile, traditional))
    n -= 2;

  for(b = builtin_array; b < builtin_array + n; b++)
    {
      cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
      hp->type = NT_MACRO;
      hp->flags |= NODE_BUILTIN | NODE_WARN;
      hp->value.builtin = b->value;
    }

  if (CPP_OPTION (pfile, cplusplus))
    _cpp_define_builtin (pfile, "__cplusplus 1");
  else if (CPP_OPTION (pfile, lang) == CLK_ASM)
    _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
  else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
    _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
  else if (CPP_OPTION (pfile, c99))
    _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");

  if (CPP_OPTION (pfile, objc))
    _cpp_define_builtin (pfile, "__OBJC__ 1");

  if (pfile->cb.register_builtins)
    (*pfile->cb.register_builtins) (pfile);
}

/* Pushes a command line -imacro and -include file indicated by P onto
   the buffer stack.  Returns nonzero if successful.  */
static bool
push_include (pfile, p)
     cpp_reader *pfile;
     struct pending_option *p;
{
  cpp_token header;

  /* Later: maybe update this to use the #include "" search path
     if cpp_read_file fails.  */
  header.type = CPP_STRING;
  header.val.str.text = (const unsigned char *) p->arg;
  header.val.str.len = strlen (p->arg);
  /* Make the command line directive take up a line.  */
  pfile->line++;

  return _cpp_execute_include (pfile, &header, IT_CMDLINE);
}

/* Frees a pending_option chain.  */
static void
free_chain (head)
     struct pending_option *head;
{
  struct pending_option *next;

  while (head)
    {
      next = head->next;
      free (head);
      head = next;
    }
}

/* Sanity-checks are dependent on command-line options, so it is
   called as a subroutine of cpp_read_main_file ().  */
#if ENABLE_CHECKING
static void sanity_checks PARAMS ((cpp_reader *));
static void sanity_checks (pfile)
     cpp_reader *pfile;
{
  cppchar_t test = 0;
  size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);

  /* Sanity checks for assumptions about CPP arithmetic and target
     type precisions made by cpplib.  */
  test--;
  if (test < 1)
    cpp_error (pfile, DL_ICE, "cppchar_t must be an unsigned type");

  if (CPP_OPTION (pfile, precision) > max_precision)
    cpp_error (pfile, DL_ICE,
	       "preprocessor arithmetic has maximum precision of %lu bits; target requires %lu bits",
	       (unsigned long) max_precision,
	       (unsigned long) CPP_OPTION (pfile, precision));

  if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
    cpp_error (pfile, DL_ICE,
	       "CPP arithmetic must be at least as precise as a target int");

  if (CPP_OPTION (pfile, char_precision) < 8)
    cpp_error (pfile, DL_ICE, "target char is less than 8 bits wide");

  if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
    cpp_error (pfile, DL_ICE,
	       "target wchar_t is narrower than target char");

  if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
    cpp_error (pfile, DL_ICE,
	       "target int is narrower than target char");

  /* This is assumed in eval_token() and could be fixed if necessary.  */
  if (sizeof (cppchar_t) > sizeof (cpp_num_part))
    cpp_error (pfile, DL_ICE, "CPP half-integer narrower than CPP character");

  if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
    cpp_error (pfile, DL_ICE,
	       "CPP on this host cannot handle wide character constants over %lu bits, but the target requires %lu bits",
	       (unsigned long) BITS_PER_CPPCHAR_T,
	       (unsigned long) CPP_OPTION (pfile, wchar_precision));
}
#else
# define sanity_checks(PFILE)
#endif

/* Add a dependency target.  Can be called any number of times before
   cpp_read_main_file().  If no targets have been added before
   cpp_read_main_file(), then the default target is used.  */
void
cpp_add_dependency_target (pfile, target, quote)
     cpp_reader *pfile;
     const char *target;
     int quote;
{
  if (!pfile->deps)
    pfile->deps = deps_init ();

  deps_add_target (pfile->deps, target, quote);
}

/* This is called after options have been parsed, and partially
   processed.  Setup for processing input from the file named FNAME,
   or stdin if it is the empty string.  Return the original filename
   on success (e.g. foo.i->foo.c), or NULL on failure.  */
const char *
cpp_read_main_file (pfile, fname, table)
     cpp_reader *pfile;
     const char *fname;
     hash_table *table;
{
  sanity_checks (pfile);

  post_options (pfile);

  /* The front ends don't set up the hash table until they have
     finished processing the command line options, so initializing the
     hashtable is deferred until now.  */
  _cpp_init_hashtable (pfile, table);

  if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
    {
      if (!pfile->deps)
	pfile->deps = deps_init ();

      /* Set the default target (if there is none already).  */
      deps_add_default_target (pfile->deps, fname);
    }

  /* Open the main input file.  */
  if (!_cpp_read_file (pfile, fname))
    return NULL;

  /* Set this here so the client can change the option if it wishes,
     and after stacking the main file so we don't trace the main
     file.  */
  pfile->line_maps.trace_includes = CPP_OPTION (pfile, print_include_names);

  /* For foo.i, read the original filename foo.c now, for the benefit
     of the front ends.  */
  if (CPP_OPTION (pfile, preprocessed))
    read_original_filename (pfile);

  return pfile->map->to_file;
}

/* For preprocessed files, if the first tokens are of the form # NUM.
   handle the directive so we know the original file name.  This will
   generate file_change callbacks, which the front ends must handle
   appropriately given their state of initialization.  */
static void
read_original_filename (pfile)
     cpp_reader *pfile;
{
  const cpp_token *token, *token1;

  /* Lex ahead; if the first tokens are of the form # NUM, then
     process the directive, otherwise back up.  */
  token = _cpp_lex_direct (pfile);
  if (token->type == CPP_HASH)
    {
      token1 = _cpp_lex_direct (pfile);
      _cpp_backup_tokens (pfile, 1);

      /* If it's a #line directive, handle it.  */
      if (token1->type == CPP_NUMBER)
	{
	  _cpp_handle_directive (pfile, token->flags & PREV_WHITE);
	  return;
	}
    }

  /* Backup as if nothing happened.  */
  _cpp_backup_tokens (pfile, 1);
}

/* Handle pending command line options: -D, -U, -A, -imacros and
   -include.  This should be called after debugging has been properly
   set up in the front ends.  */
void
cpp_finish_options (pfile)
     cpp_reader *pfile;
{
  /* Mark named operators before handling command line macros.  */
  if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
    mark_named_operators (pfile);

  /* Install builtins and process command line macros etc. in the order
     they appeared, but only if not already preprocessed.  */
  if (! CPP_OPTION (pfile, preprocessed))
    {
      struct pending_option *p;

      _cpp_do_file_change (pfile, LC_RENAME, _("<built-in>"), 1, 0);
      init_builtins (pfile);
      _cpp_do_file_change (pfile, LC_RENAME, _("<command line>"), 1, 0);
      for (p = CPP_OPTION (pfile, pending)->directive_head; p; p = p->next)
	(*p->handler) (pfile, p->arg);

      /* Scan -imacros files after -D, -U, but before -include.
	 pfile->next_include_file is NULL, so _cpp_pop_buffer does not
	 push -include files.  */
      for (p = CPP_OPTION (pfile, pending)->imacros_head; p; p = p->next)
	if (push_include (pfile, p))
	  cpp_scan_nooutput (pfile);

      pfile->next_include_file = &CPP_OPTION (pfile, pending)->include_head;
      _cpp_maybe_push_include_file (pfile);
    }

  pfile->first_unused_line = pfile->line;

  free_chain (CPP_OPTION (pfile, pending)->imacros_head);
  free_chain (CPP_OPTION (pfile, pending)->directive_head);
}

/* Push the next buffer on the stack given by -include, if any.  */
void
_cpp_maybe_push_include_file (pfile)
     cpp_reader *pfile;
{
  if (pfile->next_include_file)
    {
      struct pending_option *head = *pfile->next_include_file;

      while (head && !push_include (pfile, head))
	head = head->next;

      if (head)
	pfile->next_include_file = &head->next;
      else
	{
	  /* All done; restore the line map from <command line>.  */
	  _cpp_do_file_change (pfile, LC_RENAME,
			       pfile->line_maps.maps[0].to_file, 1, 0);
	  /* Don't come back here again.  */
	  pfile->next_include_file = NULL;
	}
    }
}

/* This is called at the end of preprocessing.  It pops the last
   buffer and writes dependency output, and returns the number of
   errors.
 
   Maybe it should also reset state, such that you could call
   cpp_start_read with a new filename to restart processing.  */
int
cpp_finish (pfile, deps_stream)
     cpp_reader *pfile;
     FILE *deps_stream;
{
  /* Warn about unused macros before popping the final buffer.  */
  if (CPP_OPTION (pfile, warn_unused_macros))
    cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);

  /* cpplex.c leaves the final buffer on the stack.  This it so that
     it returns an unending stream of CPP_EOFs to the client.  If we
     popped the buffer, we'd dereference a NULL buffer pointer and
     segfault.  It's nice to allow the client to do worry-free excess
     cpp_get_token calls.  */
  while (pfile->buffer)
    _cpp_pop_buffer (pfile);

  /* Don't write the deps file if there are errors.  */
  if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
      && deps_stream && pfile->errors == 0)
    {
      deps_write (pfile->deps, deps_stream, 72);

      if (CPP_OPTION (pfile, deps.phony_targets))
	deps_phony_targets (pfile->deps, deps_stream);
    }

  /* Report on headers that could use multiple include guards.  */
  if (CPP_OPTION (pfile, print_include_names))
    _cpp_report_missing_guards (pfile);

  return pfile->errors;
}

/* Add a directive to be handled later in the initialization phase.  */
static void
new_pending_directive (pend, text, handler)
     struct cpp_pending *pend;
     const char *text;
     cl_directive_handler handler;
{
  struct pending_option *o = (struct pending_option *)
    xmalloc (sizeof (struct pending_option));

  o->arg = text;
  o->next = NULL;
  o->handler = handler;
  APPEND (pend, directive, o);
}

/* Irix6 "cc -n32" and OSF4 cc have problems with char foo[] = ("string");
   I.e. a const string initializer with parens around it.  That is
   what N_("string") resolves to, so we make no_* be macros instead.  */
#define no_ass N_("assertion missing after %s")
#define no_fil N_("file name missing after %s")
#define no_mac N_("macro name missing after %s")

/* This is the list of all command line options, with the leading
   "-" removed.  It must be sorted in ASCII collating order.  */
#define COMMAND_LINE_OPTIONS                                                  \
  DEF_OPT("A",                        no_ass, OPT_A)                          \
  DEF_OPT("D",                        no_mac, OPT_D)                          \
  DEF_OPT("U",                        no_mac, OPT_U)                          \
  DEF_OPT("imacros",                  no_fil, OPT_imacros)                    \
  DEF_OPT("include",                  no_fil, OPT_include)

#define DEF_OPT(text, msg, code) code,
enum opt_code
{
  COMMAND_LINE_OPTIONS
  N_OPTS
};
#undef DEF_OPT

struct cl_option
{
  const char *opt_text;
  const char *msg;
  size_t opt_len;
  enum opt_code opt_code;
};

#define DEF_OPT(text, msg, code) { text, msg, sizeof(text) - 1, code },
#ifdef HOST_EBCDIC
static struct cl_option cl_options[] =
#else
static const struct cl_option cl_options[] =
#endif
{
  COMMAND_LINE_OPTIONS
};
#undef DEF_OPT
#undef COMMAND_LINE_OPTIONS

/* Perform a binary search to find which, if any, option the given
   command-line matches.  Returns its index in the option array,
   negative on failure.  Complications arise since some options can be
   suffixed with an argument, and multiple complete matches can occur,
   e.g. -pedantic and -pedantic-errors.  */
static int
parse_option (input)
     const char *input;
{
  unsigned int md, mn, mx;
  size_t opt_len;
  int comp;

  mn = 0;
  mx = N_OPTS;

  while (mx > mn)
    {
      md = (mn + mx) / 2;

      opt_len = cl_options[md].opt_len;
      comp = strncmp (input, cl_options[md].opt_text, opt_len);

      if (comp > 0)
	mn = md + 1;
      else if (comp < 0)
	mx = md;
      else
	{
	  if (input[opt_len] == '\0')
	    return md;
	  /* We were passed more text.  If the option takes an argument,
	     we may match a later option or we may have been passed the
	     argument.  The longest possible option match succeeds.
	     If the option takes no arguments we have not matched and
	     continue the search (e.g. input="stdc++" match was "stdc").  */
	  mn = md + 1;
	  if (cl_options[md].msg)
	    {
	      /* Scan forwards.  If we get an exact match, return it.
		 Otherwise, return the longest option-accepting match.
		 This loops no more than twice with current options.  */
	      mx = md;
	      for (; mn < (unsigned int) N_OPTS; mn++)
		{
		  opt_len = cl_options[mn].opt_len;
		  if (strncmp (input, cl_options[mn].opt_text, opt_len))
		    break;
		  if (input[opt_len] == '\0')
		    return mn;
		  if (cl_options[mn].msg)
		    mx = mn;
		}
	      return mx;
	    }
	}
    }

  return -1;
}

/* Handle one command-line option in (argc, argv).
   Can be called multiple times, to handle multiple sets of options.
   Returns number of strings consumed.  */
int
cpp_handle_option (pfile, argc, argv)
     cpp_reader *pfile;
     int argc;
     char **argv;
{
  int i = 0;
  struct cpp_pending *pend = CPP_OPTION (pfile, pending);

    {
      enum opt_code opt_code;
      int opt_index;
      const char *arg = 0;

      /* Skip over '-'.  */
      opt_index = parse_option (&argv[i][1]);
      if (opt_index < 0)
	return i;

      opt_code = cl_options[opt_index].opt_code;
      if (cl_options[opt_index].msg)
	{
	  arg = &argv[i][cl_options[opt_index].opt_len + 1];
	  if (arg[0] == '\0')
	    {
	      arg = argv[++i];
	      if (!arg)
		{
		  cpp_error (pfile, DL_ERROR,
			     cl_options[opt_index].msg, argv[i - 1]);
		  return argc;
		}
	    }
	}

      switch (opt_code)
	{
	case N_OPTS: /* Shut GCC up.  */
	  break;

	case OPT_D:
	  new_pending_directive (pend, arg, cpp_define);
	  break;

	case OPT_A:
	  if (arg[0] == '-')
	    {
	      /* -A with an argument beginning with '-' acts as
		 #unassert on whatever immediately follows the '-'.
		 If "-" is the whole argument, we eliminate all
		 predefined macros and assertions, including those
		 that were specified earlier on the command line.
		 That way we can get rid of any that were passed
		 automatically in from GCC.  */

	      if (arg[1] == '\0')
		{
		  free_chain (pend->directive_head);
		  pend->directive_head = NULL;
		  pend->directive_tail = NULL;
		}
	      else
		new_pending_directive (pend, arg + 1, cpp_unassert);
	    }
	  else
	    new_pending_directive (pend, arg, cpp_assert);
	  break;
	case OPT_U:
	  new_pending_directive (pend, arg, cpp_undef);
	  break;
	case OPT_include:
	case OPT_imacros:
	  {
	    struct pending_option *o = (struct pending_option *)
	      xmalloc (sizeof (struct pending_option));
	    o->arg = arg;
	    o->next = NULL;

	    if (opt_code == OPT_include)
	      APPEND (pend, include, o);
	    else
	      APPEND (pend, imacros, o);
	  }
	  break;
	}
    }
  return i + 1;
}

static void
post_options (pfile)
     cpp_reader *pfile;
{
  /* -Wtraditional is not useful in C++ mode.  */
  if (CPP_OPTION (pfile, cplusplus))
    CPP_OPTION (pfile, warn_traditional) = 0;

  /* Permanently disable macro expansion if we are rescanning
     preprocessed text.  Read preprocesed source in ISO mode.  */
  if (CPP_OPTION (pfile, preprocessed))
    {
      pfile->state.prevent_expansion = 1;
      CPP_OPTION (pfile, traditional) = 0;
    }

  /* Traditional CPP does not accurately track column information.  */
  if (CPP_OPTION (pfile, traditional))
    CPP_OPTION (pfile, show_column) = 0;
}