/* scan-decls.c - Extracts declarations from cpp output.
   Copyright (C) 1993, 1995, 1997, 1998,
   1999, 2000, 2003, 2004 Free Software Foundation, Inc.

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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

   Written by Per Bothner <bothner@cygnus.com>, July 1993.  */

#include "bconfig.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "cpplib.h"
#include "scan.h"

static void skip_to_closing_brace (cpp_reader *);
static const cpp_token *get_a_token (cpp_reader *);

int brace_nesting = 0;

/* The first extern_C_braces_length elements of extern_C_braces
   indicate the (brace nesting levels of) left braces that were
   prefixed by extern "C".  */
int extern_C_braces_length = 0;
/* 20 is not enough anymore on Solaris 9.  */
#define MAX_EXTERN_C_BRACES  200
char extern_C_braces[MAX_EXTERN_C_BRACES];
#define in_extern_C_brace (extern_C_braces_length>0)

/* True if the function declaration currently being scanned is
   prefixed by extern "C".  */
int current_extern_C = 0;

/* Get a token but skip padding.  */
static const cpp_token *
get_a_token (cpp_reader *pfile)
{
  for (;;)
    {
      const cpp_token *result = cpp_get_token (pfile);
      if (result->type != CPP_PADDING)
        return result;
    }
}

static void
skip_to_closing_brace (cpp_reader *pfile)
{
  int nesting = 1;
  for (;;)
    {
      enum cpp_ttype token = get_a_token (pfile)->type;

      if (token == CPP_EOF)
        break;
      if (token == CPP_OPEN_BRACE)
        nesting++;
      if (token == CPP_CLOSE_BRACE && --nesting == 0)
        break;
    }
}

/* This function scans a C source file (actually, the output of cpp),
   reading from FP.  It looks for function declarations, and
   external variable declarations.

   The following grammar (as well as some extra stuff) is recognized:

   declaration:
     (decl-specifier)* declarator ("," declarator)* ";"
   decl-specifier:
     identifier
     keyword
     extern "C"
   declarator:
     (ptr-operator)* dname [ "(" argument-declaration-list ")" ]
   ptr-operator:
     ("*" | "&") ("const" | "volatile")*
   dname:
     identifier

Here dname is the actual name being declared.
*/

int
scan_decls (cpp_reader *pfile, int argc ATTRIBUTE_UNUSED,
            char **argv ATTRIBUTE_UNUSED)
{
  int saw_extern, saw_inline;
  cpp_token prev_id;
  const cpp_token *token;

 new_statement:
  token = get_a_token (pfile);

 handle_statement:
  current_extern_C = 0;
  saw_extern = 0;
  saw_inline = 0;
  if (token->type == CPP_OPEN_BRACE)
    {
      /* Pop an 'extern "C"' nesting level, if appropriate.  */
      if (extern_C_braces_length
          && extern_C_braces[extern_C_braces_length - 1] == brace_nesting)
        extern_C_braces_length--;
      brace_nesting--;
      goto new_statement;
    }
  if (token->type == CPP_OPEN_BRACE)
    {
      brace_nesting++;
      goto new_statement;
    }

  if (token->type == CPP_EOF)
    return 0;

  if (token->type == CPP_SEMICOLON)
    goto new_statement;
  if (token->type != CPP_NAME)
    goto new_statement;

  prev_id.type = CPP_EOF;
  for (;;)
    {
      switch (token->type)
        {
        default:
          goto handle_statement;
        case CPP_MULT:
        case CPP_AND:
          /* skip */
          break;

        case CPP_COMMA:
        case CPP_SEMICOLON:
          if (prev_id.type != CPP_EOF && saw_extern)
            {
              recognized_extern (&prev_id);
            }
          if (token->type == CPP_COMMA)
            break;
          /* ... fall through ...  */
        case CPP_OPEN_BRACE:  case CPP_CLOSE_BRACE:
          goto new_statement;

        case CPP_EOF:
          return 0;

        case CPP_OPEN_PAREN:
          /* Looks like this is the start of a formal parameter list.  */
          if (prev_id.type != CPP_EOF)
            {
              int nesting = 1;
              int have_arg_list = 0;
              const struct line_map *map;
              unsigned int line;
              for (;;)
                {
                  token = get_a_token (pfile);
                  if (token->type == CPP_OPEN_PAREN)
                    nesting++;
                  else if (token->type == CPP_CLOSE_PAREN)
                    {
                      nesting--;
                      if (nesting == 0)
                        break;
                    }
                  else if (token->type == CPP_EOF)
                    break;
                  else if (token->type == CPP_NAME
                           || token->type == CPP_ELLIPSIS)
                    have_arg_list = 1;
                }
              map = linemap_lookup (&line_table, token->src_loc);
              line = SOURCE_LINE (map, token->src_loc);
              recognized_function (&prev_id, line,
                                   (saw_inline ? 'I'
                                    : in_extern_C_brace || current_extern_C
                                    ? 'F' : 'f'), have_arg_list);
              token = get_a_token (pfile);
              if (token->type == CPP_OPEN_BRACE)
                {
                  /* skip body of (normally) inline function */
                  skip_to_closing_brace (pfile);
                  goto new_statement;
                }

              /* skip a possible __attribute__ or throw expression after the
                 parameter list */
              while (token->type != CPP_SEMICOLON && token->type != CPP_EOF)
                token = get_a_token (pfile);
              if (token->type == CPP_EOF)
                return 0;
              goto new_statement;
            }
          break;
        case CPP_NAME:
          /* "inline" and "extern" are recognized but skipped */
          if (cpp_ideq (token, "inline"))
            {
              saw_inline = 1;
            }
          else if (cpp_ideq (token, "extern"))
            {
              saw_extern = 1;
              token = get_a_token (pfile);
              if (token->type == CPP_STRING
                  && token->val.str.len == 1
                  && token->val.str.text[0] == 'C')
                {
                  current_extern_C = 1;
                  token = get_a_token (pfile);
                  if (token->type == CPP_OPEN_BRACE)
                    {
                      brace_nesting++;
                      extern_C_braces[extern_C_braces_length++]
                        = brace_nesting;
                      if (extern_C_braces_length >= MAX_EXTERN_C_BRACES)
                        {
                          fprintf (stderr,
                                     "Internal error: out-of-bounds index\n");
                          exit (FATAL_EXIT_CODE);
                        }
                      goto new_statement;
                    }
                }
              else
                continue;
              break;
            }
          /* This may be the name of a variable or function.  */
          prev_id = *token;
          break;
        }
      token = get_a_token (pfile);
    }
}