ProfitPress Mega CDROM2 …eeware (MSDOS)(1992)(Eng)/ProfitPress-MegaCDROM2.B6I/PROG/MISC/FORCHEK1.ZIP/SYMTAB.C

C/C++ Source or Header | 1991-11-05 | 55.0 KB | 2,127 lines

/* symtab.c:

Contains formerly separate modules:
   I. Symtab: symbol table maintenance routines.
  II. Hash:  hash table functions: hash(), kwd_hash(), rehash()
 III. Intrins: handles recognition & data typing of intrinsic functions.


    Copyright (C) 1991 by Robert K. Moniot.
    This program is free software.  Permission is granted to
    modify it and/or redistribute it, retaining this notice.
    No guarantees accompany this software.


*/

/*
  I. Symtab


  Symbol table routines for Fortran program checker.

   Shared functions defined:


    call_func(id,arg)  Handles function invocations.
    call_subr(id,arg)  Handles CALL statements.
    declare_type(id,datatype) Handles TYPE statements.
    def_arg_name(id)  Handles func/subr argument lists.
    def_array_dim(id,arg) Handles dimensioning declarations.
    def_com_block(id)  Handles common blocks and SAVE stmts.
    def_com_variable(id)  Handles common block lists.
       int def_curr_module(id)  Identifies symbol as current module.
         def_equiv_name(id)  Initializes equivalence list items.
    def_ext_name(id)  Handles external lists.
    def_function(datatype,id,args)
      Installs function name in global table.
    def_intrins_name(id)  Handles intrinsic lists.
    def_parameter(id,value) Handles parameter_defn_item
    def_stmt_function(id) Declares a statement function.
    do_ASSIGN(id)  Handles ASSIGN stmts.
    do_assigned_GOTO(id)  Handles assigned GOTO.
    do_ENTRY(id,args,hashno) Processes ENTRY statement.
    do_RETURN(hashno,keyword) Processes RETURN statement.
    equivalence(id1,id2)  equivalences two variables
       int get_type(symt)  Finds out data type of symbol, or uses implicit
     typing to establish its type.
 unsigned hash_lookup(s)  Looks up identifier in hashtable.
    init_globals()  Initializes global symbol info.
    init_symtab()  Clears local symbol table & removes locals
     from stringspace. Also restores default
     implicit data typing.
 symtab* install_global(t,datatype,storage_class) Installs indentifier in
    global symbol table.
 symtab* install_local(t,datatype,storage_class) Installs indentifier in
    local symbol table.
ArgListHeader* make_arg_array(t) Converts list of tokens into list of
     type-flag pairs.
ArgListHeader* make_dummy_arg_array(t) Converts list of tokens into list of
     type-flag pairs.
ArgListHeader* make_arrayless_alist() Sets up argument list header for
    EXTERNAL decl or subprog as actual arg.
ComListHeader* make_com_array(t) Converts list of common block tokens into
     list of dimen_info-type pairs.
    process_lists()  Places pointer to linked list of arrays in
     global symbol table
    ref_array(id,subscrs) Handles array references
    ref_variable(id)  Handles accessing variable name.
    set_implicit_type(type,c1,c2) Processes IMPLICIT statement.
    stmt_function_stmt(id) Finishes processing stmt func defn.
    char * token_name(t)  Returns ptr to token's symbol's name.
    use_actual_arg(id)  Handles using a variable as actual arg.
    use_io_keyword(id_keywd,id_val,class) Handles i/o control specifier.
    use_lvalue(id)  Handles assignment to a variable.
    use_parameter(id)  Handles data_constant_value &
     data_repeat_factor.
    use_variable(id)  Sets used-flag for a variable used in expr.

*/

/*  private functions defined:
 arg_count(t)  Counts the number of arguments in a token list.
 call_external(symt,id,arg) places token list of args into local symtab
 check_intrins_args(arg, defn) Checks call seq of intrinsic functions
 check_stmt_function_args(symt,id,arg)  ditto for statement functions
 find_intrinsic()  Looks up intrinsic functions in table
 find_io_keyword()  Looks up i/o control spec keywords
 reverse_tokenlist(t)  Reverses a linked list of tokens
 make_TL_head();  Initializes a tokenlist header
*/

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#define SYMTAB
#include "forchek.h"
#include "symtab.h"
#include "tokdefs.h"
#ifdef __STDC__
#include <stdlib.h>
#else
char *calloc();
void exit();
#endif


PRIVATE
unsigned arg_count();

PRIVATE void
call_external(),
check_intrins_args(),
check_stmt_function_args();

PRIVATE int
find_io_keyword();

PRIVATE Token *
reverse_tokenlist();

PRIVATE TokenListHeader * /* Initializes a tokenlist header */
make_TL_head();

PRIVATE
ArgListHeader *make_dummy_arg_array(),*make_arg_array(),
 *make_arrayless_alist();

PRIVATE
ComListHeader *make_com_array();

PRIVATE
IntrinsInfo *find_intrinsic();

PRIVATE unsigned
arg_count(t)            /* Counts the number of arguments in a token list */
 Token *t;
{
 unsigned count;
 count = 0;
 while(t != NULL){
  count++;
  t = t->next_token;
 }
 return(count);
}

   /* This routine handles the saving of arg lists which
      is done by call_func and call_subr */
PRIVATE void
call_external(symt,id,arg)
 symtab *symt;
 Token *id,*arg;
{
        TokenListHeader *TH_ptr;

  /* Insert the new list onto linked list of token lists */
       TH_ptr= make_TL_head(id);

 TH_ptr->tokenlist = (arg == NULL ? NULL: arg->next_token);
 TH_ptr->next = symt->info.toklist;
 symt->info.toklist = TH_ptr;
} /*call_external*/

void
call_func(id,arg) /* Process function invocation */
 Token *id, *arg;
{
 int t, h=id->value.integer;
 symtab *symt,*gsymt;
 IntrinsInfo *defn;

 if( (symt = (hashtab[h].loc_symtab)) == NULL){
    symt = install_local(h,type_UNDECL,class_SUBPROGRAM);
           symt->info.toklist = NULL;
 }

 t = datatype_of(symt->type);
  /* Symbol seen before: check it & change class */

 if(storage_class_of(symt->type) == class_VAR) {
     symt->type = type_byte(class_SUBPROGRAM,t);
     symt->info.toklist = NULL;
   }


  /* See if intrinsic.  If so, set flag, save info */
    if(!symt->external && !symt->intrinsic
  && (defn = find_intrinsic(symt->name)) != NULL) {
   /* First encounter with intrinsic fcn: store info */
  symt->intrinsic = TRUE;
  symt->info.intrins_info = defn;
    }


  /* If intrinsic, do checking now.  Otherwise, save arg list
     to be checked later. */

    if(symt->intrinsic) {
   /* It is intrinsic: check it */
 check_intrins_args(arg,symt->info.intrins_info);
    }
    else {  /* It is not intrinsic: install in global table */
      switch(storage_class_of(symt->type)) {
 case class_SUBPROGRAM:
   symt->external = TRUE;
   if((!symt->argument) && (gsymt=(hashtab[h].glob_symtab)) == NULL) {
  gsymt = install_global(h,type_UNDECL,class_SUBPROGRAM);
  gsymt->info.arglist = NULL;
   }
   /* store arg list in local table */
   call_external(symt,id,arg);
   break;
 case class_STMT_FUNCTION:
   symt->external = TRUE;
   check_stmt_function_args(symt,id,arg);
   break;
      }
    }

    symt->used_flag = TRUE;
    symt->invoked_as_func = TRUE;

} /*call_func*/


void
call_subr(id,arg) /* Process call statements */
 Token *id, *arg;
{
 int t, h=id->value.integer;
 symtab *symt,*gsymt;

 if( (symt = (hashtab[h].loc_symtab)) == NULL){
    symt = install_local(h,type_SUBROUTINE,class_SUBPROGRAM);
       symt->info.toklist = NULL;
 }


 t=datatype_of(symt->type);
  /* Symbol seen before: check it & change class */

 if(t == type_UNDECL) {
  t = type_SUBROUTINE;
  symt->info.toklist = NULL;
 }
 symt->type = type_byte(class_SUBPROGRAM,t);

 /* Assume CALL cannot refer to intrinsic, so don't look to
    see if it is in intrinsic list.
    But if declared intrinsic, then accept it as such and
    do checking now.  Otherwise, save arg list
    to be checked later. */

    if(symt->intrinsic) {
   /* It is intrinsic: check it */
 check_intrins_args(arg,symt->info.intrins_info);
    }
    else {  /* It is not intrinsic: install in global table */
 symt->external = TRUE;
 if((!symt->argument) && (gsymt=(hashtab[h].glob_symtab)) == NULL) {
  gsymt = install_global(h,type_UNDECL,class_SUBPROGRAM);
  gsymt->info.arglist = NULL;
 }
   /* store arg list in local table */
 call_external(symt,id,arg);
    }

 symt->used_flag = TRUE;

}/*call_subr*/


  /* check out consistency of intrinsic argument list */
PRIVATE
void
check_intrins_args(arg, defn)
 Token *arg;
 IntrinsInfo *defn;
{
 int i;
 unsigned args_given = arg_count(arg->next_token);
 int type,firsttype;
 int numargs,argtype;
 Token *t;

 numargs = defn->num_args;
 argtype = defn->arg_type;


   /* positive numargs: must agree */
 if( (numargs > 0 && (args_given != numargs))
   /* numargs == -1: 1 or 2 */
  || (numargs == -1 && (args_given != 1 && args_given != 2))
   /* numargs == -2: 2 or more */
  || (numargs == -2 && (args_given < 2)) ){
  syntax_error(arg->line_num,arg->col_num,
    "intrinsic function used with wrong number of arguments: ");
  msg_tail(defn->name);
 }
 if(arg == NULL) return;

 t = arg->next_token;
 for(i=0; i<args_given; i++) {
     type = datatype_of(t->class);

     if(i == 0)
  firsttype = type;

     if(!( (1<<type) & argtype )) {
  syntax_error(t->line_num,t->col_num,
  "illegal argument data type for intrinsic function");
     }

     if(firsttype != type) {
  syntax_error(t->line_num,t->col_num,
  "intrinsic function argument data types differ");
     }
     t = t->next_token;
 }
}/* check_intrins_args */


PRIVATE
void
check_stmt_function_args(symt,id,arg)
 symtab *symt;
 Token *id,*arg;
{
 unsigned n1,n2,n;
 int i;
 Token *t1,*t2;

 t1 = symt->info.toklist->tokenlist;
 t2 = reverse_tokenlist( (arg==NULL? NULL : arg->next_token) );

 n1 = arg_count(t1);
 n2 = arg_count(t2);

 if(n1 != n2) {
     syntax_error(id->line_num,id->col_num,
  "function invoked with incorrect number of arguments");
 }

 n = (n1 < n2? n1: n2);
 for(i=0; i<n; i++) {

     if( t1->class != t2->class) {
  syntax_error(t2->line_num,t2->col_num,
    "function argument is of incorrect datatype");
     }
     t1 = t1->next_token;
     t2 = t2->next_token;
 }
}


void
declare_type(id,datatype)
 Token *id;
 int datatype;
{
 int h=id->value.integer;
 symtab *symt;

 if( (symt=hashtab[h].loc_symtab) == NULL) {
    symt = install_local(h,datatype,class_VAR);
 }
 else {           /* Symbol has been seen before: check it */

   /* Intrinsic: see if type is consistent */
   if( symt->intrinsic ) {
     IntrinsInfo *defn = symt->info.intrins_info;
     int rettype = defn->result_type,
  argtype = defn->arg_type;
   /* N.B. this test catches many but not all errors */
     if( (rettype != type_GENERIC && datatype != rettype)
      || (rettype == type_GENERIC && !((1<<datatype) & argtype)) ){
      warning(id->line_num,id->col_num,
    "Declared type ");
      msg_tail(type_name[datatype]);
      msg_tail(" is invalid for intrinsic function: ");
      msg_tail(symt->name);
       }
   }

   if(datatype_of(symt->type) != type_UNDECL) {
       syntax_error(id->line_num,id->col_num,
  "Symbol redeclared: ");
    msg_tail(symt->name);
   }
   else {
   /* Now give it the declared type */
       symt->type = type_byte(storage_class_of(symt->type),datatype);
   }
 }
}/*declare_type*/


void
def_arg_name(id)  /* Process items in argument list */

 Token *id;
{
 int h=id->value.integer;
 symtab *symt;

 if( (symt=hashtab[h].loc_symtab) == NULL) {
    symt = install_local(h,type_UNDECL,class_VAR);
 }
 else {           /* Symbol has been seen before: check it */

 }
 symt->argument = TRUE;
}/*def_arg_name*/


void
def_array_dim(id,arg) /* Process dimension lists */
 Token *id,*arg;      /* arg previously defined as int */
{
 int h=id->value.integer;
 symtab *symt;


 if( (symt=hashtab[h].loc_symtab) == NULL) {
    symt = install_local(h,type_UNDECL,class_VAR);
 }
 else {           /* Symbol has been seen before: check it */
    if(storage_class_of(symt->type) != class_VAR) {
       syntax_error(id->line_num,id->col_num,
  "Entity cannot be dimensioned: ");
  msg_tail(symt->name);
       return;
    }
 }
 symt->array_var = TRUE;
 if(!equivalence_flag){      /* some checking should be done here */
    if(symt->info.array_dim != 0)
       syntax_error(id->line_num,id->col_num,
  "Array redimensioned");
    else
       symt->info.array_dim = array_dim_info(arg->class,arg->subclass);
 }
}/*def_array_dim*/


void
def_com_block(id,comlist) /* Process common blocks and save_stmt */
 Token *id, *comlist;

{
 int h=id->value.integer;
 symtab *symt,*gsymt;
    TokenListHeader *TH_ptr;

  /* Install name in global symbol table */
 if( (gsymt=hashtab[h].com_glob_symtab) == NULL) {
    gsymt = install_global(h,type_COMMON_BLOCK,class_COMMON_BLOCK);
    gsymt->info.comlist = NULL;
 }


 if( (symt = hashtab[h].com_loc_symtab) == NULL){
    symt = install_local(h,type_COMMON_BLOCK,class_COMMON_BLOCK);
    symt->info.toklist = NULL;
 }

  /* Insert the new list onto linked list of token lists */
 if(comlist != NULL) {
    /* Will be NULL only for SAVE, in which case skip */
     TH_ptr= make_TL_head(id);

      TH_ptr->tokenlist = comlist->next_token;
     TH_ptr->next = symt->info.toklist;
            symt->info.toklist = TH_ptr;
 }

    symt->set_flag = TRUE;
 symt->used_flag = TRUE;
}/*def_com_block*/


void
def_com_variable(id)  /* Process items in common block list */
 Token *id;
{
 int h=id->value.integer;
 symtab *symt;

 if( (symt=hashtab[h].loc_symtab) == NULL) {
    symt = install_local(h,type_UNDECL,class_VAR);
 }
 else {           /* Symbol has been seen before: check it */
     if(symt->common_var) {
  syntax_error(id->line_num,id->col_num,
       "Variable cannot be in two different common blocks");
     }
     else if(symt->entry_point || symt->parameter ||
      symt->argument || symt->external || symt->intrinsic) {
  syntax_error(id->line_num,id->col_num,
       "Item cannot be placed in common");
     }
 }
    {  /* set flags for all equivalenced vars */
      symtab *equiv=symt;
      do{
 equiv->common_var = TRUE; /* set the flag even if not legit */
 equiv = equiv->equiv_link;
      } while(equiv != symt);
    }

}/*def_com_variable*/


 /* This guy sets the flag in symbol table saying the id is the
    current module.  It returns the hash code for later reference.
  */
int
def_curr_module(id)
 Token *id;
{
 int hashno = id->value.integer;
 hashtab[hashno].loc_symtab->is_current_module = TRUE;

 return hashno;
}/*def_curr_module*/




void
def_equiv_name(id)  /* Process equivalence list elements */
 Token *id;
{
  ref_variable(id);  /* Put it in symtab */
 /* No other action needed: processing of equiv pairs is
    done by equivalence() */
}/*def_equiv_name*/



void
def_ext_name(id)  /* Process external lists */
 Token *id;
{
 int h=id->value.integer;
 symtab *symt;

 if( (symt = hashtab[h].loc_symtab) == NULL){
    symt = install_local(h,type_UNDECL,class_SUBPROGRAM);
    symt->info.toklist = NULL;
        }
 else {
   /* Symbol seen before: check it & change class */

     if(storage_class_of(symt->type) == class_VAR) {
       symt->info.toklist = NULL;
     }
     symt->type = type_byte(class_SUBPROGRAM,datatype_of(symt->type));
 }

 if(symt->intrinsic){
     syntax_error(id->line_num,id->col_num,
  "Cannot declare same subprogram both intrinsic and external:");
     msg_tail(symt->name);
 }
 else{
     symt->external = TRUE;
     if(!symt->argument){
         TokenListHeader *TH_ptr;
  symtab *gsymt;
  if( (gsymt=hashtab[h].glob_symtab) == NULL) {
         gsymt = install_global(h,type_UNDECL,class_SUBPROGRAM);
         gsymt->info.arglist = NULL;
  }
  TH_ptr=make_TL_head(id);

  TH_ptr->external_decl = TRUE;
  TH_ptr->next = symt->info.toklist;
  symt->info.toklist = TH_ptr;
      }
   }
      symt->declared_external = TRUE;
}/*def_ext_name*/



void
def_function(datatype,id,args)
    /* Installs function or subroutine name */
 int datatype;                     /* in global table */
 Token *id,*args;
{
 int storage_class;
 int h=id->value.integer;
 symtab *symt,*gsymt;
 TokenListHeader *TH_ptr;
    storage_class = class_SUBPROGRAM;

 if((gsymt = (hashtab[h].glob_symtab)) == NULL) {
   /* Symbol is new to global symtab: install it */
   gsymt = install_global(h,datatype,storage_class);
   gsymt->info.arglist = NULL;
 }
 else {
   /* Symbol is already in global symtab. Put the
      declared datatype into symbol table. */
   gsymt->type = type_byte(storage_class,datatype);
 }

    if((symt = (hashtab[id->value.integer].loc_symtab)) == NULL) {
   /* Symbol is new to local symtab: install it.
      Since this is the current routine, it has
      storage class of a variable. */
    symt = install_local(h,datatype,class_VAR);
 }
 if(! symt->entry_point) /* seen before but not as entry */
    symt->info.toklist = NULL;


  /* Insert the new list onto linked list of token lists */
    TH_ptr=make_TL_head(id);

 TH_ptr->tokenlist = (args == NULL ? NULL: args->next_token);
 TH_ptr->next = symt->info.toklist;
 symt->info.toklist = TH_ptr;

 symt->entry_point = TRUE;

  /* library mode: set the flag so no complaint will
     be issued if function never invoked.  Also, set
     used_flag if this is a main program, for same reason. */
 if(library_mode)
  symt->library_module = TRUE;
 if(datatype == type_PROGRAM)
  symt->used_flag = TRUE;
}/*def_function*/



void
def_intrins_name(id)  /* Process intrinsic lists */
 Token *id;
{
 int h=id->value.integer;
 symtab *symt;

 if( (symt = hashtab[h].loc_symtab) == NULL){
    symt = install_local(h,type_UNDECL,class_SUBPROGRAM);
    symt->info.toklist = NULL;
        }
 else {
   /* Symbol seen before: check it & change class */
   if(storage_class_of(symt->type) == class_VAR) {
     symt->info.toklist = NULL;
   }

   symt->type = type_byte(class_SUBPROGRAM,datatype_of(symt->type));
 }

  /* Place info about intrinsic datatype in local symtab.
     If not found, it will be treated as external.
   */

 if(symt->external){
     syntax_error(id->line_num,id->col_num,
        "Cannot declare same subprogram both intrinsic and external:");
     msg_tail(symt->name);
 }
 else{
   IntrinsInfo *defn;
   if( (defn=find_intrinsic(symt->name)) == NULL ) {
      warning(id->line_num,id->col_num,
   "Unknown intrinsic function: ");
      msg_tail(symt->name);
      msg_tail("\nTreated as if user-defined");
    /* Here treat as if EXTERNAL declaration */
      def_ext_name(id);
      return;
    }
    else {
   /* Found in info table: set intrins flag and store
      pointer to definition info. */
      symt->intrinsic = TRUE;
      symt->info.intrins_info = defn;
    }
 }
 symt->declared_external = TRUE;
}/*def_intrins_name*/

void
def_parameter(id,val)  /* Process parameter_defn_item */
 Token *id,*val;
{
 int h=id->value.integer;
 symtab *symt;

 if( (symt=hashtab[h].loc_symtab) == NULL) {
    symt = install_local(h,type_UNDECL,class_VAR);
 }

 symt->set_flag = TRUE;
 symt->parameter = TRUE;
 if(incdepth > 0)
   symt->defined_in_include = TRUE;

  /* Integer parameters: save value in symtab entry.  Other
     types not saved.  Need these since used in array dims */
 switch(get_type(symt)) {
  case type_INTEGER:
   symt->info.int_value = int_expr_value(val);
   break;
  default:
   break;
 }
}/*def_parameter*/



void            /* Installs statement function name in local table */
def_stmt_function(id, args)
 Token *id, *args;
{
 int t,h=id->value.integer;
 symtab *symt;
    TokenListHeader *TH_ptr;

    if((symt = (hashtab[h].loc_symtab)) == NULL) {
   /* Symbol is new to local symtab: install it. */

    symt = install_local(h,type_UNDECL,class_STMT_FUNCTION);
    symt->info.toklist = NULL;
 }
 else {
   if(storage_class_of(symt->type) == class_VAR) {
     symt->info.toklist = NULL;
   }
 }

  /* Save dummy arg list in symbol table */
     TH_ptr= make_TL_head(id);

 TH_ptr->tokenlist = (args == NULL ? NULL: args->next_token);
 TH_ptr->next = symt->info.toklist;
 symt->info.toklist = TH_ptr;

  /* Reverse the token list for sake of checking phase */
 TH_ptr->tokenlist = reverse_tokenlist(TH_ptr->tokenlist);

 t=datatype_of(symt->type);
  /* Symbol seen before: check it & change class */

  /* check, check, check ... */
 if(storage_class_of(symt->type) == class_VAR)
    symt->type = type_byte(class_STMT_FUNCTION,t);

 symt->external = TRUE;
}/*def_stmt_function*/




void
do_ASSIGN(id)  /* Process ASSIGN statement */
 Token *id;
{
 int h=id->value.integer;
 symtab *symt;

 if( (symt=hashtab[h].loc_symtab) == NULL) {
    symt = install_local(h,type_UNDECL,class_VAR);
 }
 else {
    if(get_type(symt) != type_INTEGER) {
       syntax_error(id->line_num,id->col_num,
  "Variable must be an integer: ");
       msg_tail(symt->name);
    }
 }
    {  /* set flags for all equivalenced vars */
      symtab *equiv=symt;
      do{
 equiv->set_flag = TRUE;
 equiv = equiv->equiv_link;
      } while(equiv != symt);
    }
}/*do_ASSIGN*/




void
do_assigned_GOTO(id)  /* Process assigned_goto */
 Token *id;
{
 int h=id->value.integer;
 symtab *symt;

 if( (symt=hashtab[h].loc_symtab) == NULL) {
    symt = install_local(h,type_UNDECL,class_VAR);
 }
 else {
    if(get_type(symt) != type_INTEGER) {
       syntax_error(id->line_num,id->col_num,
  "Variable must be an integer: ");
       msg_tail(symt->name);
    }
 }
    {  /* set flags for all equivalenced vars */
      symtab *equiv=symt;
      do{
 if(! equiv->set_flag)
    equiv->used_before_set = TRUE;
 equiv->used_flag = TRUE;
 equiv = equiv->equiv_link;
      } while(equiv != symt);
    }

}/*do_assigned_GOTO*/





void
do_ENTRY(id,args,hashno) /* Processes ENTRY statement */
 Token *id,*args;
 int hashno;
{
 int datatype;
 if(hashno == -1) { /* -1 signifies headerless program */
     datatype = type_PROGRAM;
 }
 else {
     datatype = datatype_of(hashtab[hashno].loc_symtab->type);
 }
 switch(datatype) {
     case type_PROGRAM:
     case type_BLOCK_DATA:
     case type_COMMON_BLOCK:
         syntax_error(id->line_num,NO_COL_NUM,
   "You cannot have an entry statement here");
  break;
     case type_SUBROUTINE: /* Subroutine entry */
  def_function(type_SUBROUTINE,id,args);
  break;
     default:  /* Function entry */
  def_function(type_UNDECL,id,args);
  break;
 }
}/*do_ENTRY*/




 /* This routine checks whether a RETURN statement is valid at
    the present location, and if it is, looks for possible
    failure to assign return value of function.
 */
void
do_RETURN(hashno,keyword)
 int hashno; /* current module hash number */
 Token *keyword; /* tok_RETURN, or tok_END if implied RETURN */
{
 int i,datatype;
 if(hashno == -1) { /* -1 signifies headerless program */
     datatype = type_PROGRAM;
 }
 else {
     datatype = datatype_of(hashtab[hashno].loc_symtab->type);
 }
 switch(datatype) {
     case type_PROGRAM:
     case type_BLOCK_DATA:
  if(keyword->class == tok_RETURN)
      syntax_error(keyword->line_num,keyword->col_num,
       "You cannot have a RETURN statement here!");
  break;
     case type_SUBROUTINE: /* Subroutine return: OK */
  break;
     default:  /* Function return: check whether entry
       points have been assigned values. */
  for(i=0; i<loc_symtab_top; i++) {
      if(storage_class_of(loc_symtab[i].type) == class_VAR
   && loc_symtab[i].entry_point
   && ! loc_symtab[i].set_flag ) {
       warning(keyword->line_num,keyword->col_num,
     loc_symtab[i].name);
       msg_tail("not set when RETURN encountered");
      }
  }
  break;
 }

}/*do_RETURN*/

void
equivalence(id1,id2)
     Token *id1, *id2;
{
 int h1=id1->value.integer, h2=id2->value.integer;
 symtab *symt1,*symt2,*temp;

  /* install the variables in symtab if not seen before */
 if( (symt1=hashtab[h1].loc_symtab) == NULL) {
    symt1 = install_local(h1,type_UNDECL,class_VAR);
 }
 if( (symt2=hashtab[h2].loc_symtab) == NULL) {
    symt2 = install_local(h2,type_UNDECL,class_VAR);
 }
   /* Check for legality.  Ought to do complementary
      checks elsewhere.
    */
 if(symt1 == symt2
    || symt1->parameter || symt2->parameter
    || symt1->entry_point || symt2->entry_point
    || symt1->argument || symt2->argument
    || symt1->external || symt2->external) {

  syntax_error(id1->line_num,id1->col_num,
        "illegal to equivalence these");
 }
  /* now swap equiv_links so their equiv lists are united */
 else {
     temp = symt1->equiv_link;
     symt1->equiv_link = symt2->equiv_link;
     symt2->equiv_link = temp;
 }

  /* If either guy is in common, both are in common */
 if(symt1->common_var || symt2->common_var) {
     symtab *equiv=symt1;
     do {
  equiv->common_var = TRUE;
  equiv = equiv->equiv_link;
     } while(equiv != symt1);
 }
}

int
get_type(symt) /* Returns data type of symbol, using implicit if necessary */
 symtab *symt;
{
 int datatype = datatype_of(symt->type);

 if(datatype != type_UNDECL) /* Declared? */
    return datatype;  /*   Yes: use it */
 else if(storage_class_of(symt->type) == class_SUBPROGRAM
      && !symt->invoked_as_func )
    /* Function never invoked: assume subr */
    return type_SUBROUTINE;
 else   /* Otherwise use implicit type */
#if ALLOW_UNDERSCORES
    return (isupper((int)symt->name[0]))?
      implicit_type[symt->name[0] - 'A']:
        type_REAL; /* 1st char underscore => REAL */
#else
    return implicit_type[symt->name[0] - 'A'];
#endif
}/*get_type*/


 /* hash_lookup finds identifier in hashtable and returns its
    index.  If not found, a new hashtable entry is made for it,
    and the identifier string s is copied to local stringspace.
 */
unsigned
hash_lookup(s)
 char *s;
{
        unsigned h;
 unsigned long hnum;

 hnum = hash(s);

 while(h = hnum%HASHSZ, hashtab[h].name != NULL
           && strcmp(hashtab[h].name,s) != 0) {
     hnum = rehash(hnum); /* Resolve clashes */
 }

 if(hashtab[h].name == NULL) {
      hashtab[h].name = new_local_string(s);
      hashtab[h].loc_symtab = NULL;
      hashtab[h].glob_symtab = NULL;
      hashtab[h].com_loc_symtab = NULL;
      hashtab[h].com_glob_symtab = NULL;
        }
 return h;
}/*hash_lookup*/

void
init_globals()                 /* Clears the global symbol table */
{
 glob_str_bot = STRSPACESZ;
}/*init_globals*/



void
init_symtab()                     /* Clears the local symbol table */
{
 int i,h;
 unsigned long hnum;

 loc_symtab_top = 0;
 loc_str_top = 0;
 token_space_top = 0;

        /* Clears the hash table */
 for(i=0;i<HASHSZ;i++) {
     hashtab[i].name = NULL;
     hashtab[i].loc_symtab = NULL;
     hashtab[i].com_loc_symtab = NULL;
     hashtab[i].glob_symtab = NULL;
     hashtab[i].com_glob_symtab = NULL;
 }

        /* Re-establishes global symbols */
 for(i=0;i<glob_symtab_top;i++) {
     hnum = hash(glob_symtab[i].name);
     while (h=hnum % HASHSZ, hashtab[h].name != NULL
        && strcmp(hashtab[h].name,glob_symtab[i].name) != 0 ) {
        hnum = rehash(hnum);
     }
     hashtab[h].name = glob_symtab[i].name;
     if(storage_class_of(glob_symtab[i].type) == class_COMMON_BLOCK)
  hashtab[h].com_glob_symtab = &(glob_symtab[i]);
     else
  hashtab[h].glob_symtab = &(glob_symtab[i]);

 }

        /* Restores implicit typing to default values */
 {
  int c;
  for( c=0; c<26; c++ )
          implicit_type[c] = type_REAL;
  for( c='I'-'A'; c <= 'N'-'A'; c++ )
      implicit_type[c] = type_INTEGER;
 }
}/*init_symtab*/



symtab*
install_global(h,datatype,storage_class) /* Install a global symbol */
 int h;   /* hash index */
 int datatype,storage_class;
{
 symtab *gsymt = &glob_symtab[glob_symtab_top];

 if(glob_symtab_top == GLOBSYMTABSZ) {
  fprintf(stderr,
   "\nOops! out of space in global symbol table.\n");
  exit(1);
 }
 else {
   /* Store symtab pointer in hash table */
     if(storage_class == class_COMMON_BLOCK)
  hashtab[h].com_glob_symtab = gsymt;
     else
  hashtab[h].glob_symtab = gsymt;

    /* Duplicate copy of string into global stringspace */
     gsymt->name = new_global_string(hashtab[h].name);

   /* Set symtab info fields */
     gsymt->type = type_byte(storage_class,datatype);
     if(storage_class == class_COMMON_BLOCK)
  gsymt->info.comlist = NULL;
     else
  gsymt->info.arglist = NULL;
     clear_symtab_flags(gsymt);

     ++glob_symtab_top;
 }
 return (gsymt);
}/*install_global*/


symtab*
install_local(h,datatype,storage_class) /* Install a local symbol */
 int h;   /* hash index */
 int datatype,storage_class;
{
 symtab *symt = &loc_symtab[loc_symtab_top];
 if(loc_symtab_top == LOCSYMTABSZ) {
  fprintf(stderr,
   "\nOops! out of space in local symbol table.\n");
  exit(1);
 }
 else {
     if(storage_class == class_COMMON_BLOCK)
  hashtab[h].com_loc_symtab = symt;
     else
  hashtab[h].loc_symtab = symt;
     symt->name = hashtab[h].name;
     symt->info.array_dim = 0;

        /* Set symtab info fields */
     symt->type = type_byte(storage_class,datatype);
     symt->equiv_link = symt; /* equivalenced only to self */
     clear_symtab_flags(symt);
     ++loc_symtab_top;
 }
 return symt;
}/*install_local*/


  /* Get value specified by an integer-expression token.
     This will be either an identifier, which should be a
     parameter whose value is in the symbol table, or else
     an expression token as propagated by exprtype.c
     routines, with value stored in the token.
  */
int
int_expr_value(t)
 Token *t;
{
    if(! is_true(CONST_EXPR,t->subclass) ) {
 syntax_error(t->line_num,t->col_num,"constant expression required");
 return 0;
    }
    else {
 if( is_true(ID_EXPR,t->subclass) ) {
  /* Identifier: better be a parameter */
     int h=t->value.integer;
     symtab *symt = hashtab[h].loc_symtab;
     if(symt == NULL || !(symt->parameter) ) {
  syntax_error(t->line_num,t->col_num,
   "constant expression required");
  return 0;
     }
     else {
  return symt->info.int_value;
     }
 }
  /* Otherwise, it is a const or expr, use token.value.integer */
 else {
     return t->value.integer;
 }
    }
}/*int_expr_value*/


 /* Following routine converts a list of tokens into a list of type-
    flag pairs. */

PRIVATE ArgListHeader *
make_arg_array(t)
 Token *t;  /* List of tokens */
{
 int i;
 unsigned count;
 Token *s;
 ArgListElement *arglist;
 ArgListHeader *alhead;

 count = arg_count(t);
 if(((alhead=(ArgListHeader *) calloc(1, sizeof(ArgListHeader)))
      == (ArgListHeader *) NULL) ||
   (count != 0 &&
          ((arglist=(ArgListElement *) calloc(count,sizeof(ArgListElement)))
     == (ArgListElement *) NULL))){
  fprintf(stderr, "Out of space for argument list");
  exit(1);
 }
 s = t;            /* List of tokens is in reverse order. */
 for(i=count-1; i>=0; i--){  /* Here we fill array in original order. */

     arglist[i].type = s->class; /* use evaluated type, not symt */

   /* Keep track of array and external declarations */
     if( is_true(ID_EXPR,s->subclass) ){
  int h = s->value.integer;
  symtab *symt = hashtab[h].loc_symtab;
  if( (arglist[i].info.array_dim = symt->info.array_dim) == 0)
    /* change scalars to 0 dims, size 1 */
    arglist[i].info.array_dim = array_dim_info(0,1);
  arglist[i].array_var = symt->array_var;
  arglist[i].declared_external = symt->declared_external;
     }
     else {
  arglist[i].info.array_dim = 0;
  arglist[i].array_var = FALSE;
  arglist[i].declared_external = FALSE;
     }

     arglist[i].array_element =
  arglist[i].array_var && !is_true(ARRAY_ID_EXPR,s->subclass);

     if( is_true(LVALUE_EXPR,s->subclass) ){
  arglist[i].is_lvalue = TRUE;
   /* is_true(f,x) yields 0 or non-0: convert to 0 or 1 */
  arglist[i].set_flag =
   is_true(SET_FLAG,s->subclass)? TRUE: FALSE;
  arglist[i].assigned_flag =
   is_true(ASSIGNED_FLAG,s->subclass)? TRUE: FALSE;
  arglist[i].used_before_set =
   is_true(USED_BEFORE_SET,s->subclass)? TRUE: FALSE;
     }
     else { /* it is an expression or constant, not an lvalue */
  arglist[i].is_lvalue = FALSE;
  arglist[i].set_flag = TRUE;
  arglist[i].assigned_flag = FALSE;
  arglist[i].used_before_set = FALSE;
     }
     s = s->next_token;
 }
 alhead->numargs = count;
 alhead->is_defn = FALSE;
 alhead->is_call = TRUE;
 alhead->external_decl = FALSE;
 alhead->actual_arg = FALSE;

        if (count == 0)
  alhead->arg_array = NULL;
 else
  alhead->arg_array = arglist;
 return(alhead);
}/* make_arg_array */


 /* Following routine converts a list of common block tokens
     into a list of dimen_info-type pairs. */

PRIVATE ComListHeader *
make_com_array(t)
 Token *t;  /* List of tokens */
{
 Token *s;
 symtab *symt;
 int h, i;
 unsigned count;
 ComListHeader *clhead;
 ComListElement *comlist;

 count = arg_count(t);
 if(((clhead=(ComListHeader *) calloc(1,sizeof(ComListHeader)))
   == (ComListHeader *) NULL) ||
   (count != 0 &&
    ((comlist=(ComListElement *) calloc(count,sizeof(ComListElement)))
   == (ComListElement *) NULL))){
  fprintf(stderr, "Out of space for common list");
  exit(1);
 }
 s = t;
 for(i=count-1; i>=0; i--){
    h = s->value.integer;
    symt = hashtab[h].loc_symtab;
    if( (comlist[i].dimen_info = symt->info.array_dim) == 0)
    /* change scalars to 0 dims, size 1 */
      comlist[i].dimen_info = array_dim_info(0,1);
    comlist[i].type = get_type(symt);
    s = s->next_token;
 }
 clhead->numargs = count;
 if (count == 0)
  clhead->com_list_array = NULL;
 else
  clhead->com_list_array = comlist;
 return(clhead);
} /* make_com_array */


PRIVATE ArgListHeader *
make_dummy_arg_array (t)
 Token *t;  /* List of tokens */
{
 int i;
 unsigned count;
 Token *s;
 ArgListElement *arglist;
 ArgListHeader *alhead;

 count = arg_count(t);
 if(((alhead=(ArgListHeader *) calloc(1, sizeof(ArgListHeader)))
    == (ArgListHeader *) NULL) ||
   (count != 0 &&
          ((arglist=(ArgListElement *) calloc(count,sizeof(ArgListElement)))
   == (ArgListElement *) NULL))){
  fprintf(stderr, "Out of space for argument list");
  exit(1);
 }
 s = t;            /* List of tokens is in reverse order. */
 for(i=count-1; i>=0; i--){  /* Here we fill array in original order. */
     if( is_true(ID_EXPR,s->subclass) ){
  int h = s->value.integer;
  symtab *symt = hashtab[h].loc_symtab;
  if( (arglist[i].info.array_dim = symt->info.array_dim) == 0)
    /* change scalars to 0 dims, size 1 */
    arglist[i].info.array_dim = array_dim_info(0,1);
  arglist[i].type = type_byte(storage_class_of(symt->type),
      get_type(symt));
  arglist[i].is_lvalue = TRUE;
  arglist[i].set_flag = symt->set_flag;
  arglist[i].assigned_flag = symt->assigned_flag;
  arglist[i].used_before_set = symt->used_before_set;
  arglist[i].array_var = symt->array_var;
  arglist[i].array_element = FALSE;
  arglist[i].declared_external = symt->declared_external;
     }
     else { /* It is a label */
  arglist[i].info.array_dim = 0;
  arglist[i].type = s->class;
  arglist[i].is_lvalue = FALSE;
  arglist[i].set_flag = FALSE; /* Don't currently do labels */
  arglist[i].assigned_flag = FALSE;
  arglist[i].used_before_set = FALSE;
  arglist[i].array_var = FALSE;
  arglist[i].array_element = FALSE;
  arglist[i].declared_external = FALSE;
     }
     s = s->next_token;
 }
 alhead->numargs = count;
 alhead->is_defn = TRUE;
 alhead->is_call = FALSE;
 alhead->external_decl = FALSE;
 alhead->actual_arg = FALSE;

        if (count == 0)
  alhead->arg_array = NULL;
 else
  alhead->arg_array = arglist;
 return(alhead);
}/* make_dummy_arg_array */


 /* This routine makes an empty argument list: used for
    EXTERNAL declarations of subprograms. */
PRIVATE ArgListHeader *
make_arrayless_alist()
{
 ArgListHeader *alhead;

 if(((alhead=(ArgListHeader *) calloc(1, sizeof(ArgListHeader)))
      == (ArgListHeader *) NULL) ) {
  fprintf(stderr, "Out of space for external decl\n");
  exit(1);
 }

 alhead->numargs = 0;
 alhead->is_defn = FALSE;
 alhead->is_call = FALSE;
 alhead->arg_array = NULL;

 return(alhead);
}/* make_arrayless_arglist */

PRIVATE TokenListHeader * /* Initializes a tokenlist header */
make_TL_head(t)
     Token *t;
{
  TokenListHeader *TH_ptr;

       if((TH_ptr=(TokenListHeader *) calloc(1,sizeof(TokenListHeader)))
     == (TokenListHeader *) NULL){
    fprintf(stderr,"Out of space for token list");
    exit(1);
 }

 TH_ptr->line_num = t->line_num;
   TH_ptr->filename = current_filename;
    /* Clear all the flags */
 TH_ptr->external_decl = FALSE;
 TH_ptr->actual_arg = FALSE;
 TH_ptr->tokenlist = NULL;
 TH_ptr->next = NULL;

  return TH_ptr;
}

  /* this routine allocates room in global part (top down)
     of stringspace for string s, and copies it there */
char *
new_global_string(s)
 char *s;
{
 glob_str_bot -= strlen(s) + 1;    /*pre-decrement*/
 if( glob_str_bot < loc_str_top ) {
     fprintf(stderr,"\noops: out of global stringspace.\n");
     exit(1);
 }
 return strcpy(strspace+glob_str_bot,s);
}/*new_global_string*/

  /* Allocate space for string s in local (bottom up)
     string space, and copy it there */
char *
new_local_string(s)
 char *s;
{
 char *start = strspace + loc_str_top;
 loc_str_top += strlen(s) + 1; /* post-increment */
 if(loc_str_top > glob_str_bot) {
     fprintf(stderr,"\noops: out of stringspace\n");
      exit(1);
 }

 return strcpy(start,s);
}/* new_local_string */

Token *
new_token()   /* Returns pointer to space for a token */
{
  if(token_space_top == TOKENSPACESZ)
    return (Token *)NULL;
  else
    return tokenspace + token_space_top++;
}

 /* note_filename():  This routine is called by main prog to give
    symbol table routines access to current input file name, to be
    stored in function arg list headers and common list headers, for
    the use in diagnostic messages. Since filenames are from argv,
    they are permanent, so pointer is copied, not the string.
 */
void
note_filename(s)
 char *s;
{
 current_filename = s;
 top_filename = s;
}/* note_filename */



void
process_lists(curmodhash)  /* Places pointer to linked list of arrays in
         global symbol table */
 int curmodhash;    /* current_module_hash from fortran.y */
{
 int i, h;
 unsigned long hnum;
 symtab *gsymt;
 TokenListHeader *head_ptr;

 for (i=0; i<loc_symtab_top; i++){
    /* Skip things which are not true externals */
     if(loc_symtab[i].argument || loc_symtab[i].intrinsic ||
     loc_symtab[i].array_var)
        continue;

     head_ptr = loc_symtab[i].info.toklist;

     hnum=hash(loc_symtab[i].name);
     while(h=hnum%HASHSZ,hashtab[h].name != NULL
   && strcmp(hashtab[h].name,loc_symtab[i].name)!=0){
        hnum = rehash(hnum);      /* Resolve clashes */
     }

     switch (storage_class_of(loc_symtab[i].type)){
      case class_COMMON_BLOCK:
   if(head_ptr != NULL) {
if((gsymt=hashtab[h].com_glob_symtab) == NULL)
    fprintf(stderr,"\nOops! common block %s not in global symtab",
 loc_symtab[i].name);
else {
   Token *tok_ptr;
                        ComListHeader *c;

    /* First we link up possibly multiple
       declarations of the same common block
       in this module into one big list */
       while (tok_ptr = head_ptr->tokenlist,
          (head_ptr = head_ptr->next) != NULL){
       while(tok_ptr->next_token != NULL){
           tok_ptr = tok_ptr->next_token;
       }
       tok_ptr->next_token = head_ptr->tokenlist;
   }

    /* Now make it into array for global table */
          c=make_com_array(loc_symtab[i].info.toklist->tokenlist);
   c->module = (curmodhash == -1) ? NULL:
        hashtab[curmodhash].glob_symtab;
   c->line_num = loc_symtab[i].info.toklist->line_num;
   c->filename = loc_symtab[i].info.toklist->filename;
   c->topfile = top_filename;

                        c->next = gsymt->info.comlist;
   gsymt->info.comlist = c;
  /* Replace token list by comlist for project file use */
   loc_symtab[i].info.comlist = c;
}
   }/* end if(head_ptr != NULL) */

          break; /* end case class_COMMON_BLOCK */


   /* Are we inside a function or subroutine? */
      case class_VAR:
         if(loc_symtab[i].entry_point) {
if((gsymt=hashtab[h].glob_symtab) == NULL)
    fprintf(stderr,"\nOops! subprog %s not in global symtab",
 loc_symtab[i].name);
else {
                          ArgListHeader *a;

    /* Make each token list into an array of
       args for global table */
     while (head_ptr != NULL){
        a=make_dummy_arg_array(head_ptr->tokenlist);

        a->type = type_byte(
            class_SUBPROGRAM,
     get_type(&(loc_symtab[i])));
        a->module = (curmodhash == -1) ? NULL:
        hashtab[curmodhash].glob_symtab;
        a->filename = head_ptr->filename;
        a->topfile = top_filename;
        a->line_num = head_ptr->line_num;

        a->next = gsymt->info.arglist;
        gsymt->info.arglist = a;
   /* store arglist in local symtab for project file */
        loc_symtab[i].info.arglist = a;
        head_ptr = head_ptr->next;
            }/* end while (head_ptr != NULL) */

     if(loc_symtab[i].set_flag)
            gsymt->set_flag = TRUE;
     if(loc_symtab[i].used_flag)
            gsymt->used_flag = TRUE;
     if(loc_symtab[i].declared_external)
     gsymt->declared_external = TRUE;
     if(loc_symtab[i].library_module)
     gsymt->library_module = TRUE;
}
   }/* end if(loc_symtab[i].entry_point) */

       break; /* end case class_VAR */

                    case class_SUBPROGRAM:
if((gsymt=hashtab[h].glob_symtab) == NULL)
    fprintf(stderr,"\nOops! subprog %s not in global symtab",
 loc_symtab[i].name);
else {
                        ArgListHeader *a;
   while (head_ptr != NULL){
     if(head_ptr->external_decl || head_ptr->actual_arg)
       a=make_arrayless_alist();
     else
       a=make_arg_array(head_ptr->tokenlist);

     a->type = type_byte(
            class_SUBPROGRAM,
     get_type(&(loc_symtab[i])));
     a->module = (curmodhash == -1) ? NULL:
        hashtab[curmodhash].glob_symtab;
     a->filename = head_ptr->filename;
     a->topfile = top_filename;
     a->line_num = head_ptr->line_num;
     a->external_decl = head_ptr->external_decl;
     a->actual_arg = head_ptr->actual_arg;

     a->next = gsymt->info.arglist;
     gsymt->info.arglist = a;
  /* put arglist into local symtab for project file use */
     loc_symtab[i].info.arglist = a;
     head_ptr = head_ptr->next;
          }
   if(loc_symtab[i].used_flag)
           gsymt->used_flag = TRUE;
if(debug_glob_symtab)
fprintf(list_fd,"\nmodule %s local used=%d global used=%d",
gsymt->name,loc_symtab[i].used_flag,gsymt->used_flag);
}
   break;/* end case class_SUBPROGRAM*/

     }/* end switch */

        }/* end for (i=0; i<loc_symtab_top; i++) */

}/* process_lists */


void
ref_array(id,subscrs)   /* Array reference: install in symtab */
 Token *id, *subscrs;
{
 int h=id->value.integer;
 symtab *symt=hashtab[h].loc_symtab;

 if(symt == NULL){
    fprintf(stderr, "\nOops -- undeclared variable %s has dim info",
       hashtab[h].name);
    symt = install_local(h,type_UNDECL,class_VAR);
 }
 else{    /* check that subscrs match dimension info */


   if(arg_count(subscrs->next_token)!=array_dims(symt->info.array_dim)){
       syntax_error(subscrs->line_num,subscrs->col_num,
   "array");
       msg_tail(symt->name);
       msg_tail("referenced with wrong no. of subscripts");
   }
 }
}/* ref_array */

void
ref_variable(id) /* Variable reference: install in symtab */
 Token *id;
{
 int h=id->value.integer;

 if( hashtab[h].loc_symtab == NULL) {
    (void) install_local(h,type_UNDECL,class_VAR);
 }

}/*ref_variable*/

  /* this guy reverses a tokenlist and returns a pointer
     to the new head. */
PRIVATE Token *
reverse_tokenlist(t)
 Token *t;
{
 Token *curr,*next,*temp;

 if(t == NULL)
     return t;

 curr = t;
 next = curr->next_token;
 while(next != NULL) {
  temp = next->next_token;
  next->next_token = curr;
  curr = next;
  next = temp;
 }
 t->next_token = NULL;  /* former head is now tail */
 return curr;   /* curr now points to new head */
}

 /* Following routine sets the implicit typing of characters in
    range c1 to c2 to the given type. */
void
set_implicit_type(type,c1,c2)
 int type,  /* Data type of IMPLICIT declaration */
     c1,   /* First character of range */
     c2;   /* Last character of range */
{
 int c;

 if(c2 < c1) {
  yyerror("IMPLICIT range must be in alphabetical order");
 }

  /* Fill in the lookup table for the given range of chars */
 for(c=c1; c<=c2; c++)
  implicit_type[c-'A'] = type;
}/*set_implicit_type*/

  /* Finish processing statement function.
     Clears all used-before-set flags of ordinary
     variables. Reason: statement functions are processed
     like assignment to an array element, setting ubs flags.
     At this point, no valid setting of ubs flags should
     be possible, so clearing them will elim false messages.*/
void
stmt_function_stmt(id)
     Token *id;
{
    int i;
    for(i=0; i<loc_symtab_top; i++) {
 if(storage_class_of(loc_symtab[i].type) == class_VAR &&
    ! loc_symtab[i].parameter )
   loc_symtab[i].used_before_set = FALSE;
    }
}/*stmt_function_stmt(id)*/

char *
token_name(t)
 Token t;
{
 return hashtab[t.value.integer].name;
}/*token_name*/




void
use_actual_arg(id) /* like use_lvalue except does not set assigned_flag */
 Token *id;
{
 int h=id->value.integer;
 symtab *symt;

 if((symt=hashtab[h].loc_symtab) == NULL) {
     symt = install_local(h,type_UNDECL,class_VAR);
 }
 else {
   /* if an external, set up tokenlist for "call"  */
   if(storage_class_of(symt->type) == class_SUBPROGRAM) {
       TokenListHeader *TH_ptr;
       TH_ptr= make_TL_head(id);

       TH_ptr->actual_arg = TRUE;
       TH_ptr->next = symt->info.toklist;
       symt->info.toklist = TH_ptr;
   }
 }

    {  /* set flags for all equivalenced vars */
      symtab *equiv=symt;
      do{
 equiv->set_flag = TRUE;
 equiv = equiv->equiv_link;
      } while(equiv != symt);
    }

}/*use_actual_arg*/

void
use_implied_do_index(id)
 Token *id;
{
  /* Like use_lvalue and use_variable but clears ubs flag.
            This is because we cannot handle used-before-set
     properly in this case, and the odds are that ubs
     was set in the preceding I/O list. */
 int h=id->value.integer;
 symtab *symt;

 use_lvalue(id);
 use_variable(id);
 symt=hashtab[h].loc_symtab;

 symt->used_before_set = FALSE;
}/*use_implied_do_index*/


 /* use_io_keyword handles keyword=value fields in i/o control lists */

#include "iokeywds.h"

void
use_io_keyword(keyword,value,stmt_class)
     Token *keyword,*value;
     int stmt_class;
{
    int i, k, stmt_flag=0, type_flag, setit,useit;
    int hkey=keyword->value.integer;

  /* Convert statement_class (a token class) into
     a bit flag compatible with io_keywords table. */
    for(i=0; i<NUM_IO_STMTS; i++) {
 if(local_class[i].stmt_class == stmt_class) {
     stmt_flag = local_class[i].stmt_flag;
     break;
 }
    }
    if(stmt_flag == 0) {
 fprintf(list_fd,"\nOops -- %d is not an i/o statement class",
  stmt_class);
 return;
    }
  /* Convert value datatype into
     a bit flag compatible with io_keywords table.
     Note that '*' is handled by using type_UNDECL */
    if(value->class == '*')
 type_flag = STAR;
    else
 type_flag = (1<<value->class);

    /* Look up keyword in table*/
    k = find_io_keyword(hashtab[hkey].name);

  /* Not found or nonstandard: issue warning.  Note
     that not-found is also nonstandard. */
    if(io_keywords[k].nonstandard
#ifdef VMS_IO /* special VMS case: OPEN(...,NAME=str,...) */
       || (io_keywords[k].special && stmt_flag==OP)
#endif /*VMS_IO*/
    ) {
  /* If nonstandard and -f77 flag given, issue warning */
 if(f77_standard) {
     nonstandard(keyword->line_num,keyword->col_num);
 }
 if(io_keywords[k].name == NULL) {
     if(f77_standard) { /* abbrev warning if nonstd message given */
  msg_tail(": unrecognized keyword");
     }
     else {
  warning(keyword->line_num,keyword->col_num,
  "Unrecognized keyword");
     }
     msg_tail(hashtab[hkey].name);
     msg_tail("--\n  Forchek may process incorrectly");
 }
    }

 /* If label expected, switch integer const to label */
    if( (LAB & io_keywords[k].allowed_types)
       &&  (type_flag == INT && is_true(NUM_CONST,value->subclass))) {
 type_flag = LAB;
    }

 /*  Now check it out */


  /* Check if keyword is allowed with statement */

    if(!(stmt_flag & io_keywords[k].allowed_stmts)) {
 syntax_error(keyword->line_num,keyword->col_num,
       "keyword illegal in this context");
    }

  /* Check if the type is OK */

    if( !(type_flag & io_keywords[k].allowed_types) ) {
 syntax_error(value->line_num,value->col_num,
       "control specifier is incorrect type");
    }


 /* Now handle usage */

    /* internal file?: WRITE(UNIT=str,...) */
    if(stmt_flag == WR && type_flag == CHR
     && io_keywords[k].allowed_types == UID) {
 setit = TRUE;
 useit = FALSE;
    }
    /* INQUIRE: set it if inquire_set flag true */
    else if(stmt_flag == INQ && io_keywords[k].inquire_set) {
 setit = TRUE;
 useit = FALSE;
    }
    /* otherwise use use/set flags in table */
    else {
 useit = io_keywords[k].implies_use;
 setit = io_keywords[k].implies_set;
    }
   /* Update usage status if a variable. */
    if(useit) {
 if( is_true(ID_EXPR,value->subclass)) {
     use_variable(value);
 }
    }
    if(setit) {   /* if value is set, must be an lvalue */
 if( is_true(ID_EXPR,value->subclass)) {
     use_lvalue(value);
 }
 else {
     syntax_error(value->line_num,value->col_num,
    "variable required");
 }
    }
}

void
use_lvalue(id) /* handles scalar lvalue */
 Token *id;
{
 int h=id->value.integer;
 symtab *symt;
 if((symt=hashtab[h].loc_symtab) == NULL) {
     symt = install_local(h,type_UNDECL,class_VAR);
 }
 else {
   /*   check match to previous invocations and update  */
 }
    {  /* set flags for all equivalenced vars */
      symtab *equiv=symt;
      do{
 equiv->set_flag = TRUE;
 equiv->assigned_flag = TRUE;
 equiv = equiv->equiv_link;
      } while(equiv != symt);
    }

}/*use_lvalue*/



void                    /* Process data_constant_value & data_repeat_factor */
use_parameter(id)
 Token *id;
{
 int h=id->value.integer;
 symtab *symt;

 if( (symt=hashtab[h].loc_symtab) == NULL) {
    symt = install_local(h,type_UNDECL,class_VAR);
 }
 if(! symt->parameter) {
  syntax_error(id->line_num,id->col_num,
   "must be a parameter");
  symt->parameter = TRUE;
 }

 if(! symt->set_flag) {
    symt->used_before_set = TRUE;
 }
 symt->used_flag = TRUE;

}/*use_parameter*/


void
use_var_as_subscr(id) /* Like use_variable but invokes use_actual_arg
      if id is an external.  This occurs when a
      subprogram is passed as arg of a function. */
 Token *id;
{
 int h=id->value.integer;
 symtab *symt;

 if( (symt=hashtab[h].loc_symtab) == NULL) {
    symt = install_local(h,type_UNDECL,class_VAR);
 }

 if(storage_class_of(symt->type) == class_SUBPROGRAM)
   use_actual_arg(id);
 else
   use_variable(id);

}/*use_var_as_subscr*/

void
use_variable(id)  /* Set the use-flag of variable. */
 Token *id;
{
 int h=id->value.integer;
 symtab *symt;

 if( (symt=hashtab[h].loc_symtab) == NULL) {
    symt = install_local(h,type_UNDECL,class_VAR);
 }

    {  /* set flags for all equivalenced vars */
      symtab *equiv=symt;
      do{
 if(! equiv->set_flag) {
    equiv->used_before_set = TRUE;
 }
 equiv->used_flag = TRUE;
 equiv = equiv->equiv_link;
      } while(equiv != symt);
    }

}/*use_variable*/


/*  End of symtab.c */

/*

 II. Hash

*/

/*    hash.c:
  performs a hash function

This was formerly a separate file.

*/

extern int sixclash; /* flag to check clashes in 1st 6 chars of name */

unsigned long
hash(s)
    char *s;
{
    unsigned long sum = 0, wd;
    int i = 0,j;

    int n = strlen(s);
    if(sixclash && n > 6) n = 6;

    while (i < n) {
         wd = 0;
         for(j=1; j <= sizeof(long) && i < n; i++,j++) {
            wd += (unsigned long)(s[i] & 0xff) << (sizeof(long) - j) * 8;}

 sum ^= wd;}
    return sum;
}

  /* Same as hash() but always uses full length of keyword.
     To keep the keyword table clash-free on any machine,
     packs only 4 bytes per word even if long is bigger */
unsigned long
kwd_hash(s)
    char *s;
{
    unsigned long sum = 0, wd;
    int i = 0,j;

    int n = strlen(s);

    while (i < n) {
         wd = 0;
         for(j=1; j <= 4 && i < n; i++,j++) {
            wd += (unsigned long)(s[i] & 0xff) << (4 - j) * 8;}

 sum ^= wd;}
    return sum;
}



/*    rehash.c
        performs a rehash for resolving clashes.
*/

#ifdef COUNT_REHASHES
unsigned long rehash_count=0;
#endif

unsigned long
rehash(hnum)
    unsigned long hnum;
{
#ifdef COUNT_REHASHES
    rehash_count++;
#endif
    return hnum+1;
}


/*  End of hash */


/*

III. Intrins

*/

/* intrinsic.c:

 Handles datatyping of intrinsic functions.
*/


 /* File intrinsic.h contains information from Table 5, pp. 15-22
    to 15-25 of the standard.  Note: num_args == -1 means 1 or 2 args,
    num_args == -2 means 2 or more args.  Value of arg_type is the OR
    of all allowable types (I, R, etc. as defined above).  Value of
    result_type is type returned by function (type_INTEGER, etc.).
    If result_type is type_GENERIC, function type is same as arg type.
 */


IntrinsInfo intrinsic[]={
#include "intrins.h"
};

#define NUM_INTRINSICS (sizeof(intrinsic)/sizeof(intrinsic[0]))

#define EMPTY 255

unsigned char intrins_hashtab[INTRINS_HASHSZ];

/*    init_intrins_hashtab:
                 Initializes the intrinsic hash table by clearing it to EMPTY
                 and then hashes all the intrinsic names into the table.
*/

unsigned long
init_intrins_hashtab()
{
    unsigned i,h;
    unsigned long hnum;
    unsigned long numclashes=0;

    for(h=0;h<INTRINS_HASHSZ;h++) {
           intrins_hashtab[h] = EMPTY;
    }
    for(i=0; i < NUM_INTRINSICS; i++) {
    hnum = kwd_hash(intrinsic[i].name);
    while(h=hnum%INTRINS_HASHSZ, intrins_hashtab[h] != EMPTY) {
  hnum = rehash(hnum);
  numclashes++;
    }
    intrins_hashtab[h] = i;
    }
    return numclashes;
}

 /* Function to look up an intrinsic function name in table.
    If found, returns ptr to table entry, otherwise NULL.
 */
PRIVATE IntrinsInfo *
find_intrinsic(s)
 char *s;   /* given name */
{
 unsigned i, h;
 unsigned long hnum;

 hnum = kwd_hash(s);
 while( h=hnum%INTRINS_HASHSZ, (i=intrins_hashtab[h]) != EMPTY &&
  strcmp(s,intrinsic[i].name) != 0) {
   hnum = rehash(hnum);
 }

 if(i != EMPTY) {
     return &intrinsic[i];
 }
 else
     return (IntrinsInfo *)NULL;
}

 /* find_io_keyword looks up an i/o keyword in io_keywords
    table and returns its index.  Uses simple linear search
    since not worth hash overhead.  If not found, returns
    index of last element of list, which is special. */
PRIVATE int
find_io_keyword(s)
     char *s;   /* given name */
{
    int i;
    for(i=0; io_keywords[i].name != NULL; i++) {
 if(strcmp(io_keywords[i].name, s) == 0) {
     break;
 }
    }
    return i;
}