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/* CPP Library - traditional lexical analysis and macro expansion.

   Copyright (C) 2002, 2004, 2005, 2007, 2008, 2009

   Free Software Foundation, Inc.

   Contributed by Neil Booth, May 2002

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/>.  */

#include "config.h"

#include "system.h"

#include "cpplib.h"

#include "internal.h"

/* The replacement text of a function-like macro is stored as a

   contiguous sequence of aligned blocks, each representing the text

   between subsequent parameters.

   Each block comprises the text between its surrounding parameters,

   the length of that text, and the one-based index of the following

   parameter.  The final block in the replacement text is easily

   recognizable as it has an argument index of zero.  */

struct block

{

  unsigned int text_len;

  unsigned short arg_index;

  uchar text[1];

};

#define BLOCK_HEADER_LEN offsetof (struct block, text)

#define BLOCK_LEN(TEXT_LEN) CPP_ALIGN (BLOCK_HEADER_LEN + (TEXT_LEN))

/* Structure holding information about a function-like macro

   invocation.  */

struct fun_macro

{

  /* Memory buffer holding the trad_arg array.  */

  _cpp_buff *buff;

  /* An array of size the number of macro parameters + 1, containing

     the offsets of the start of each macro argument in the output

     buffer.  The argument continues until the character before the

     start of the next one.  */

  size_t *args;

  /* The hashnode of the macro.  */

  cpp_hashnode *node;

  /* The offset of the macro name in the output buffer.  */

  size_t offset;

  /* The line the macro name appeared on.  */

  source_location line;

  /* Zero-based index of argument being currently lexed.  */

  unsigned int argc;

};

/* Lexing state.  It is mostly used to prevent macro expansion.  */

enum ls {ls_none = 0,            /* Normal state.  */

         ls_fun_open,           /* When looking for '('.  */

         ls_fun_close,          /* When looking for ')'.  */

         ls_defined,            /* After defined.  */

         ls_defined_close,      /* Looking for ')' of defined().  */

         ls_hash,               /* After # in preprocessor conditional.  */

         ls_predicate,          /* After the predicate, maybe paren?  */

         ls_answer};            /* In answer to predicate.  */

/* Lexing TODO: Maybe handle space in escaped newlines.  Stop lex.c

   from recognizing comments and directives during its lexing pass.  */

static const uchar *skip_whitespace (cpp_reader *, const uchar *, int);

static cpp_hashnode *lex_identifier (cpp_reader *, const uchar *);

static const uchar *copy_comment (cpp_reader *, const uchar *, int);

static void check_output_buffer (cpp_reader *, size_t);

static void push_replacement_text (cpp_reader *, cpp_hashnode *);

static bool scan_parameters (cpp_reader *, cpp_macro *);

static bool recursive_macro (cpp_reader *, cpp_hashnode *);

static void save_replacement_text (cpp_reader *, cpp_macro *, unsigned int);

static void maybe_start_funlike (cpp_reader *, cpp_hashnode *, const uchar *,

                                 struct fun_macro *);

static void save_argument (struct fun_macro *, size_t);

static void replace_args_and_push (cpp_reader *, struct fun_macro *);

static size_t canonicalize_text (uchar *, const uchar *, size_t, uchar *);

/* Ensures we have N bytes' space in the output buffer, and

   reallocates it if not.  */

static void

check_output_buffer (cpp_reader *pfile, size_t n)

{

  /* We might need two bytes to terminate an unterminated comment, and

     one more to terminate the line with a NUL.  */

  n += 2 + 1;

  if (n > (size_t) (pfile->out.limit - pfile->out.cur))

    {

      size_t size = pfile->out.cur - pfile->out.base;

      size_t new_size = (size + n) * 3 / 2;

      pfile->out.base = XRESIZEVEC (unsigned char, pfile->out.base, new_size);

      pfile->out.limit = pfile->out.base + new_size;

      pfile->out.cur = pfile->out.base + size;

    }

}

/* Skip a C-style block comment in a macro as a result of -CC.

   Buffer->cur points to the initial asterisk of the comment.  */

static void

skip_macro_block_comment (cpp_reader *pfile)

{

  const uchar *cur = pfile->buffer->cur;

  cur++;

  if (*cur == '/')

    cur++;

  /* People like decorating comments with '*', so check for '/'

     instead for efficiency.  */

  while(! (*cur++ == '/' && cur[-2] == '*') )

    ;

  pfile->buffer->cur = cur;

}

/* CUR points to the asterisk introducing a comment in the current

   context.  IN_DEFINE is true if we are in the replacement text of a

   macro.

   The asterisk and following comment is copied to the buffer pointed

   to by pfile->out.cur, which must be of sufficient size.

   Unterminated comments are diagnosed, and correctly terminated in

   the output.  pfile->out.cur is updated depending upon IN_DEFINE,

   -C, -CC and pfile->state.in_directive.

   Returns a pointer to the first character after the comment in the

   input buffer.  */

static const uchar *

copy_comment (cpp_reader *pfile, const uchar *cur, int in_define)

{

  bool unterminated, copy = false;

  source_location src_loc = pfile->line_table->highest_line;

  cpp_buffer *buffer = pfile->buffer;

  buffer->cur = cur;

  if (pfile->context->prev)

    unterminated = false, skip_macro_block_comment (pfile);

  else

    unterminated = _cpp_skip_block_comment (pfile);

  if (unterminated)

    cpp_error_with_line (pfile, CPP_DL_ERROR, src_loc, 0,

                         "unterminated comment");

  /* Comments in directives become spaces so that tokens are properly

     separated when the ISO preprocessor re-lexes the line.  The

     exception is #define.  */

  if (pfile->state.in_directive)

    {

      if (in_define)

        {

          if (CPP_OPTION (pfile, discard_comments_in_macro_exp))

            pfile->out.cur--;

          else

            copy = true;

        }

      else

        pfile->out.cur[-1] = ' ';

    }

  else if (CPP_OPTION (pfile, discard_comments))

    pfile->out.cur--;

  else

    copy = true;

  if (copy)

    {

      size_t len = (size_t) (buffer->cur - cur);

      memcpy (pfile->out.cur, cur, len);

      pfile->out.cur += len;

      if (unterminated)

        {

          *pfile->out.cur++ = '*';

          *pfile->out.cur++ = '/';

        }

    }

  return buffer->cur;

}

/* CUR points to any character in the input buffer.  Skips over all

   contiguous horizontal white space and NULs, including comments if

   SKIP_COMMENTS, until reaching the first non-horizontal-whitespace

   character or the end of the current context.  Escaped newlines are

   removed.

   The whitespace is copied verbatim to the output buffer, except that

   comments are handled as described in copy_comment().

   pfile->out.cur is updated.

   Returns a pointer to the first character after the whitespace in

   the input buffer.  */

static const uchar *

skip_whitespace (cpp_reader *pfile, const uchar *cur, int skip_comments)

{

  uchar *out = pfile->out.cur;

  for (;;)

    {

      unsigned int c = *cur++;

      *out++ = c;

      if (is_nvspace (c))

        continue;

      if (c == '/' && *cur == '*' && skip_comments)

        {

          pfile->out.cur = out;

          cur = copy_comment (pfile, cur, false /* in_define */);

          out = pfile->out.cur;

          continue;

        }

      out--;

      break;

    }

  pfile->out.cur = out;

  return cur - 1;

}

/* Lexes and outputs an identifier starting at CUR, which is assumed

   to point to a valid first character of an identifier.  Returns

   the hashnode, and updates out.cur.  */

static cpp_hashnode *

lex_identifier (cpp_reader *pfile, const uchar *cur)

{

  size_t len;

  uchar *out = pfile->out.cur;

  cpp_hashnode *result;

  do

    *out++ = *cur++;

  while (is_numchar (*cur));

  CUR (pfile->context) = cur;

  len = out - pfile->out.cur;

  result = CPP_HASHNODE (ht_lookup (pfile->hash_table, pfile->out.cur,

                                    len, HT_ALLOC));

  pfile->out.cur = out;

  return result;

}

/* Overlays the true file buffer temporarily with text of length LEN

   starting at START.  The true buffer is restored upon calling

   restore_buff().  */

void

_cpp_overlay_buffer (cpp_reader *pfile, const uchar *start, size_t len)

{

  cpp_buffer *buffer = pfile->buffer;

  pfile->overlaid_buffer = buffer;

  pfile->saved_cur = buffer->cur;

  pfile->saved_rlimit = buffer->rlimit;

  pfile->saved_line_base = buffer->next_line;

  buffer->need_line = false;

  buffer->cur = start;

  buffer->line_base = start;

  buffer->rlimit = start + len;

}

/* Restores a buffer overlaid by _cpp_overlay_buffer().  */

void

_cpp_remove_overlay (cpp_reader *pfile)

{

  cpp_buffer *buffer = pfile->overlaid_buffer;

  buffer->cur = pfile->saved_cur;

  buffer->rlimit = pfile->saved_rlimit;

  buffer->line_base = pfile->saved_line_base;

  buffer->need_line = true;

  pfile->overlaid_buffer = NULL;

}

/* Reads a logical line into the output buffer.  Returns TRUE if there

   is more text left in the buffer.  */

bool

_cpp_read_logical_line_trad (cpp_reader *pfile)

{

  do

    {

      if (pfile->buffer->need_line && !_cpp_get_fresh_line (pfile))

        return false;

    }

  while (!_cpp_scan_out_logical_line (pfile, NULL) || pfile->state.skipping);

  return pfile->buffer != NULL;

}

/* Set up state for finding the opening '(' of a function-like

   macro.  */

static void

maybe_start_funlike (cpp_reader *pfile, cpp_hashnode *node, const uchar *start, struct fun_macro *macro)

{

  unsigned int n = node->value.macro->paramc + 1;

  if (macro->buff)

    _cpp_release_buff (pfile, macro->buff);

  macro->buff = _cpp_get_buff (pfile, n * sizeof (size_t));

  macro->args = (size_t *) BUFF_FRONT (macro->buff);

  macro->node = node;

  macro->offset = start - pfile->out.base;

  macro->argc = 0;

}

/* Save the OFFSET of the start of the next argument to MACRO.  */

static void

save_argument (struct fun_macro *macro, size_t offset)

{

  macro->argc++;

  if (macro->argc <= macro->node->value.macro->paramc)

    macro->args[macro->argc] = offset;

}

/* Copies the next logical line in the current buffer (starting at

   buffer->cur) to the output buffer.  The output is guaranteed to

   terminate with a NUL character.  buffer->cur is updated.

   If MACRO is non-NULL, then we are scanning the replacement list of

   MACRO, and we call save_replacement_text() every time we meet an

   argument.  */

bool

_cpp_scan_out_logical_line (cpp_reader *pfile, cpp_macro *macro)

{

  bool result = true;

  cpp_context *context;

  const uchar *cur;

  uchar *out;

  struct fun_macro fmacro;

  unsigned int c, paren_depth = 0, quote;

  enum ls lex_state = ls_none;

  bool header_ok;

  const uchar *start_of_input_line;

  fmacro.buff = NULL;

  fmacro.args = NULL;

  fmacro.node = NULL;

  fmacro.offset = 0;

  fmacro.line = 0;

  fmacro.argc = 0;

  quote = 0;

  header_ok = pfile->state.angled_headers;

  CUR (pfile->context) = pfile->buffer->cur;

  RLIMIT (pfile->context) = pfile->buffer->rlimit;

  pfile->out.cur = pfile->out.base;

  pfile->out.first_line = pfile->line_table->highest_line;

  /* start_of_input_line is needed to make sure that directives really,

     really start at the first character of the line.  */

  start_of_input_line = pfile->buffer->cur;

 new_context:

  context = pfile->context;

  cur = CUR (context);

  check_output_buffer (pfile, RLIMIT (context) - cur);

  out = pfile->out.cur;

  for (;;)

    {

      if (!context->prev

          && cur >= pfile->buffer->notes[pfile->buffer->cur_note].pos)

        {

          pfile->buffer->cur = cur;

          _cpp_process_line_notes (pfile, false);

        }

      c = *cur++;

      *out++ = c;

      /* Whitespace should "continue" out of the switch,

         non-whitespace should "break" out of it.  */

      switch (c)

        {

        case ' ':

        case '\t':

        case '\f':

        case '\v':

        case '\0':

          continue;

        case '\n':

          /* If this is a macro's expansion, pop it.  */

          if (context->prev)

            {

              pfile->out.cur = out - 1;

              _cpp_pop_context (pfile);

              goto new_context;

            }

          /* Omit the newline from the output buffer.  */

          pfile->out.cur = out - 1;

          pfile->buffer->cur = cur;

          pfile->buffer->need_line = true;

          CPP_INCREMENT_LINE (pfile, 0);

          if ((lex_state == ls_fun_open || lex_state == ls_fun_close)

              && !pfile->state.in_directive

              && _cpp_get_fresh_line (pfile))

            {

              /* Newlines in arguments become a space, but we don't

                 clear any in-progress quote.  */

              if (lex_state == ls_fun_close)

                out[-1] = ' ';

              cur = pfile->buffer->cur;

              continue;

            }

          goto done;

        case '<':

          if (header_ok)

            quote = '>';

          break;

        case '>':

          if (c == quote)

            quote = 0;

          break;

        case '"':

        case '\'':

          if (c == quote)

            quote = 0;

          else if (!quote)

            quote = c;

          break;

        case '\\':

          /* Skip escaped quotes here, it's easier than above.  */

          if (*cur == '\\' || *cur == '"' || *cur == '\'')

            *out++ = *cur++;

          break;

        case '/':

          /* Traditional CPP does not recognize comments within

             literals.  */

          if (!quote && *cur == '*')

            {

              pfile->out.cur = out;

              cur = copy_comment (pfile, cur, macro != 0);

              out = pfile->out.cur;

              continue;

            }

          break;

        case '_':

        case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':

        case 'g': case 'h': case 'i': case 'j': case 'k': case 'l':

        case 'm': case 'n': case 'o': case 'p': case 'q': case 'r':

        case 's': case 't': case 'u': case 'v': case 'w': case 'x':

        case 'y': case 'z':

        case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':

        case 'G': case 'H': case 'I': case 'J': case 'K': case 'L':

        case 'M': case 'N': case 'O': case 'P': case 'Q': case 'R':

        case 'S': case 'T': case 'U': case 'V': case 'W': case 'X':

        case 'Y': case 'Z':

          if (!pfile->state.skipping && (quote == 0 || macro))

            {

              cpp_hashnode *node;

              uchar *out_start = out - 1;

              pfile->out.cur = out_start;

              node = lex_identifier (pfile, cur - 1);

              out = pfile->out.cur;

              cur = CUR (context);

              if (node->type == NT_MACRO

                  /* Should we expand for ls_answer?  */

                  && (lex_state == ls_none || lex_state == ls_fun_open)

                  && !pfile->state.prevent_expansion)

                {

                  /* Macros invalidate MI optimization.  */

                  pfile->mi_valid = false;

                  if (! (node->flags & NODE_BUILTIN)

                      && node->value.macro->fun_like)

                    {

                      maybe_start_funlike (pfile, node, out_start, &fmacro);

                      lex_state = ls_fun_open;

                      fmacro.line = pfile->line_table->highest_line;

                      continue;

                    }

                  else if (!recursive_macro (pfile, node))

                    {

                      /* Remove the object-like macro's name from the

                         output, and push its replacement text.  */

                      pfile->out.cur = out_start;

                      push_replacement_text (pfile, node);

                      lex_state = ls_none;

                      goto new_context;

                    }

                }

              else if (macro && (node->flags & NODE_MACRO_ARG) != 0)

                {

                  /* Found a parameter in the replacement text of a

                     #define.  Remove its name from the output.  */

                  pfile->out.cur = out_start;

                  save_replacement_text (pfile, macro, node->value.arg_index);

                  out = pfile->out.base;

                }

              else if (lex_state == ls_hash)

                {

                  lex_state = ls_predicate;

                  continue;

                }

              else if (pfile->state.in_expression

                       && node == pfile->spec_nodes.n_defined)

                {

                  lex_state = ls_defined;

                  continue;

                }

            }

          break;

        case '(':

          if (quote == 0)

            {

              paren_depth++;

              if (lex_state == ls_fun_open)

                {

                  if (recursive_macro (pfile, fmacro.node))

                    lex_state = ls_none;

                  else

                    {

                      lex_state = ls_fun_close;

                      paren_depth = 1;

                      out = pfile->out.base + fmacro.offset;

                      fmacro.args[0] = fmacro.offset;

                    }

                }

              else if (lex_state == ls_predicate)

                lex_state = ls_answer;

              else if (lex_state == ls_defined)

                lex_state = ls_defined_close;

            }

          break;

        case ',':

          if (quote == 0 && lex_state == ls_fun_close && paren_depth == 1)

            save_argument (&fmacro, out - pfile->out.base);

          break;

        case ')':

          if (quote == 0)

            {

              paren_depth--;

              if (lex_state == ls_fun_close && paren_depth == 0)

                {

                  cpp_macro *m = fmacro.node->value.macro;

                  m->used = 1;

                  lex_state = ls_none;

                  save_argument (&fmacro, out - pfile->out.base);

                  /* A single zero-length argument is no argument.  */

                  if (fmacro.argc == 1

                      && m->paramc == 0

                      && out == pfile->out.base + fmacro.offset + 1)

                    fmacro.argc = 0;

                  if (_cpp_arguments_ok (pfile, m, fmacro.node, fmacro.argc))

                    {

                      /* Remove the macro's invocation from the

                         output, and push its replacement text.  */

                      pfile->out.cur = (pfile->out.base

                                             + fmacro.offset);

                      CUR (context) = cur;

                      replace_args_and_push (pfile, &fmacro);

                      goto new_context;

                    }

                }

              else if (lex_state == ls_answer || lex_state == ls_defined_close)

                lex_state = ls_none;

            }

          break;

        case '#':

          if (cur - 1 == start_of_input_line

              /* A '#' from a macro doesn't start a directive.  */

              && !pfile->context->prev

              && !pfile->state.in_directive)

            {

              /* A directive.  With the way _cpp_handle_directive

                 currently works, we only want to call it if either we

                 know the directive is OK, or we want it to fail and

                 be removed from the output.  If we want it to be

                 passed through (the assembler case) then we must not

                 call _cpp_handle_directive.  */

              pfile->out.cur = out;

              cur = skip_whitespace (pfile, cur, true /* skip_comments */);

              out = pfile->out.cur;

              if (*cur == '\n')

                {

                  /* Null directive.  Ignore it and don't invalidate

                     the MI optimization.  */

                  pfile->buffer->need_line = true;

                  CPP_INCREMENT_LINE (pfile, 0);

                  result = false;

                  goto done;

                }

              else

                {

                  bool do_it = false;

                  if (is_numstart (*cur)

                      && CPP_OPTION (pfile, lang) != CLK_ASM)

                    do_it = true;

                  else if (is_idstart (*cur))

                    /* Check whether we know this directive, but don't

                       advance.  */

                    do_it = lex_identifier (pfile, cur)->is_directive;

                  if (do_it || CPP_OPTION (pfile, lang) != CLK_ASM)

                    {

                      /* This is a kludge.  We want to have the ISO

                         preprocessor lex the next token.  */

                      pfile->buffer->cur = cur;

                      _cpp_handle_directive (pfile, false /* indented */);

                      result = false;

                      goto done;

                    }

                }

            }

          if (pfile->state.in_expression)

            {

              lex_state = ls_hash;

              continue;

            }

          break;

        default:

          break;

        }

      /* Non-whitespace disables MI optimization and stops treating

         '<' as a quote in #include.  */

      header_ok = false;

      if (!pfile->state.in_directive)

        pfile->mi_valid = false;

      if (lex_state == ls_none)

        continue;

      /* Some of these transitions of state are syntax errors.  The

         ISO preprocessor will issue errors later.  */

      if (lex_state == ls_fun_open)

        /* Missing '('.  */

        lex_state = ls_none;

      else if (lex_state == ls_hash

               || lex_state == ls_predicate

               || lex_state == ls_defined)

        lex_state = ls_none;

      /* ls_answer and ls_defined_close keep going until ')'.  */

    }