symbol.c

/* symbol.c - manage all kinds of symbols */
/* (c) in 2014-2023 by Volker Barthelmann and Frank Wille */

#include "vasm.h"


symbol *first_symbol;

static symbol *saved_symbol;
static const char *last_global_label=emptystr;

#ifndef SYMHTABSIZE
#define SYMHTABSIZE 0x10000
#endif
static hashtable *symhash;

#ifdef HAVE_REGSYMS
static hashtable *regsymhash;
#endif


static void print_type(FILE *f,symbol *p)
{
  static const char *typename[] = {"???","obj","func","sect","file"};
  int t;

  if (p == NULL)
    ierror(0);
  t = TYPE(p);
  fprintf(f,"type=%s ",typename[t<=TYPE_LAST?t:0]);
}


void print_symbol(FILE *f,symbol *p)
{
  if (p == NULL)
    ierror(0);	/* this is usually an error in a cpu-backend, don't crash! */

  fprintf(f,"%s ",p->name);

  if (p->type == LABSYM)
    fprintf(f,"LAB (%#llx) ",ULLTADDR(p->pc));
  if (p->type == IMPORT)
    fprintf(f,"IMP ");
  if (p->type == EXPRESSION){
    fprintf(f,"EXPR(");
    print_expr(f,p->expr);
    fprintf(f,") ");
  }
  if (!(p->flags & (USED|VASMINTERN)))
    fprintf(f,"UNUSED ");
  if (p->flags & VASMINTERN)
    fprintf(f,"INTERNAL ");
  if (p->flags & EXPORT)
    fprintf(f,"EXPORT ");
  if (p->flags & COMMON)
    fprintf(f,"COMMON ");
  if (p->flags & WEAK)
    fprintf(f,"WEAK ");
  if (p->flags & LOCAL)
    fprintf(f,"LOCAL ");
  if (p->flags & XREF)
    fprintf(f,"XREF ");
  if (p->flags & XDEF)
    fprintf(f,"XDEF ");
  if (p->flags & PROTECTED)
    fprintf(f,"PROT ");
  if (p->flags & REFERENCED)
    fprintf(f,"REF ");
  if (p->flags & ABSLABEL)
    fprintf(f,"ABS ");
  if (p->flags & EQUATE)
    fprintf(f,"EQU ");
  if (p->flags & REGLIST)
    fprintf(f,"REGL ");
  if (TYPE(p))
    print_type(f,p);
  if (p->size){
    fprintf(f,"size=");
    print_expr(f,p->size);
    fprintf(f," ");
  }
  if (p->align)
    fprintf(f,"align=%lu ",(unsigned long)p->align);
  if (p->sec)
    fprintf(f,"sec=%s ",p->sec->name);
}


const char *get_bind_name(symbol *p)
{
  if (p->flags & EXPORT)
    return "global";
  else if (p->flags & WEAK)
    return "weak";
  else if (p->flags & LOCAL)
    return "local";
  return "unknown";
}


void add_symbol(symbol *p)
{
  hashdata data;

  p->next = first_symbol;
  first_symbol = p;
  data.ptr = p;
  add_hashentry(symhash,p->name,data);
}


symbol *find_symbol(const char *name)
{
  hashdata data;
  if (!find_name(symhash,name,&data))
    return 0;
  return data.ptr;
}


void refer_symbol(symbol *sym,const char *refname)
/* refer to an existing symbol with an additional name */
{
  hashdata data;
  data.ptr=sym;
  add_hashentry(symhash,refname,data);
}


void save_symbols(void)
/* remember current list of symbols to be restored later */
{
  saved_symbol = first_symbol;
}


void restore_symbols(void)
/* restore to a previously saved symbol list */
{
  symbol *firstprot=NULL, *lastprot=NULL;
  symbol *symp;

  if (saved_symbol) {
    while (first_symbol != saved_symbol) {
      symp = first_symbol;
      first_symbol = symp->next;
      if (symp->flags & PROTECTED) {
        /* keep this symbol */
        symp->next = firstprot;
        firstprot = symp;
        if (!lastprot)
          lastprot = symp;
      }
      else {
        rem_hashentry(symhash,symp->name,nocase);
        myfree((void *)symp->name);
        myfree(symp);
      }
    }
    if (firstprot) {
      /* add protected symbols to the list again */
      lastprot->next = first_symbol;
      first_symbol = firstprot;
    }
    saved_symbol = NULL;
  }
}


int check_symbol(const char *name)
/* issue an error when symbol is already defined in the current source */
{
  symbol *sym;

  if (sym = find_symbol(name)) {
    if (sym->type != IMPORT) {
      general_error(67,name);  /* repeatedly defined symbol */
      return 1;
    }
  }
  return 0;
}


const char *set_last_global_label(const char *name)
{
  const char *prevlgl = last_global_label;

  last_global_label = name;
  return prevlgl;
}


int is_local_symbol_name(const char *name)
/* returns true when name belongs to a symbol with local scope */
{
  return *name==' ' && strchr(name+1,' ')!=NULL;
}


const char *real_symbol_name(symbol *sym)
/* return local symbol name or NULL if symbol is not local */
{
  return is_local_symbol_name(sym->name) ?
         (strchr(sym->name+1,' ') + 1) : sym->name;
}


strbuf *make_local_label(int n,
                         const char *glob,int glen,const char *loc,int llen)
/* construct a local label of the form:
   " " + global_label_name + " " + local_label_name
   return a pointer to one of two static string buffers */
{
  static strbuf buf[EXPBUFNO+1];
  char *p;

  if (glen == 0) {
    /* use the last defined global label */
    glob = last_global_label;
    glen = strlen(last_global_label);
  }
  p = strbuf_alloc(&buf[n],llen+glen+3);
  *p++ = ' ';
  if (glen) {
    memcpy(p,glob,glen);
    p += glen;
  }
  *p++ = ' ';
  memcpy(p,loc,llen);
  *(p + llen) = '\0';
  buf[n].len = llen+glen+2;  /* new string length in buffer */
  return &buf[n];
}


symbol *new_abs(const char *name,expr *tree)
{
  symbol *new = find_symbol(name);
  int add;

  if (new) {
    if (new->flags & EQUATE)
      general_error(67,name); /* repeatedly defined symbol (error) */
    if (new->type!=IMPORT && new->type!=EXPRESSION)
      general_error(5,name);  /* symbol redefined (warning) */
    add=0;
  }
  else {
    new = mymalloc(sizeof(*new));
    new->name = mystrdup(name);
    add = 1;
  }

  new->type = EXPRESSION;
  new->sec = 0;
  new->expr = tree;

  if (add) {
    add_symbol(new);
    new->flags = 0;
    new->size = 0;
    new->align = 0;
  }
  return new;
}


symbol *new_equate(const char *name,expr *tree)
{
  symbol *sym;

  check_symbol(name);
  sym = new_abs(name,tree);
  sym->flags |= EQUATE;  /* not allowed to change this absolute symbol */
  return sym;
}


symbol *new_import(const char *name)
{
  symbol *new = find_symbol(name);

  if (new)
    return new;

  new = mymalloc(sizeof(*new));
  new->type = IMPORT;
  new->flags = 0;
  new->name = mystrdup(name);
  new->sec = 0;
  new->pc = 0;
  new->size = 0;
  new->align = 0;
  add_symbol(new);
  return new;
}


symbol *new_labsym(section *sec,const char *name)
{
  symbol *new;
  int add;

  if (chklabels) {
    hashdata data;

    if (find_name_nc(mnemohash,name,&data))
      general_error(39);  /* name conflicts with mnemonic */
    else if (find_name_nc(dirhash,name,&data))
      general_error(40);  /* name conflicts with directive */
  }

  if (!sec) {
    sec = default_section();
    if (!sec) {
      general_error(3);
      return new_import(name);
    }
  }

  sec->flags |= HAS_SYMBOLS;

  if (sec->flags & LABELS_ARE_LOCAL) {
    strbuf *buf;
    buf = make_local_label(1,sec->name,strlen(sec->name),name,strlen(name));
    name = buf->str;
  }

  if (new = find_symbol(name)) {
    if (new->type == IMPORT) {
      if (new->flags & XREF)
        general_error(85,name);  /* must not be defined */
    }
    else {
      symbol *old = new;

      new = mymalloc(sizeof(*new));
      *new = *old;
      general_error(74,name);  /* label redefined (error) */
    }
    add = 0;
  }
  else {
    new = mymalloc(sizeof(*new));
    new->name = mystrdup(name);
    add = 1;
  }

  new->type = LABSYM;
  new->sec = sec;
  new->pc = sec->pc;

  if (add) {
    add_symbol(new);
    new->flags = 0;
    new->size = 0;
    new->align = 0;
  }

  if (*name != ' ')
    last_global_label = new->name;

  if (sec->flags & ABSOLUTE)
    new->flags |= ABSLABEL;
  else
    new->flags &= ~ABSLABEL;

  return new;
}


symbol *new_tmplabel(section *sec)
{
  static unsigned long tmplabcnt = 0;
  char tmpnam[16];

  sprintf(tmpnam," *tmp%09lu*",tmplabcnt++);
  return new_labsym(sec,tmpnam);
}


symbol *internal_abs(const char *name)
{
  symbol *new = find_symbol(name);

  if (new) {
    if (new->type!=EXPRESSION || (new->flags&(EXPORT|COMMON|WEAK)))
      general_error(37,name);  /* internal symbol redefined by user */
  }
  else {
    new = new_abs(name,number_expr(0));
    new->flags |= VASMINTERN;
  }
  return new;
}


expr *set_internal_abs(const char *name,taddr newval)
{
  symbol *sym = internal_abs(name);
  expr *oldexpr = sym->expr;
  taddr oldval;

  if (oldexpr == NULL)
    ierror(0);
  eval_expr(oldexpr,&oldval,NULL,0);
  if (newval != oldval)
    sym->expr = number_expr(newval);
  return oldexpr;
}


#ifdef HAVE_REGSYMS
void add_regsym(regsym *rsym)
{
  hashdata data;

  data.ptr = rsym;
  add_hashentry(regsymhash,rsym->reg_name,data);
}


regsym *find_regsym(const char *name,int len)
{
  hashdata data;

  if (find_namelen(regsymhash,name,len,&data))
    return data.ptr;
  return NULL;
}


regsym *find_regsym_nc(const char *name,int len)
{
  hashdata data;

  if (find_namelen_nc(regsymhash,name,len,&data))
    return data.ptr;
  return NULL;
}


regsym *new_regsym(int redef,int no_case,const char *name,int type,
                   unsigned int flags,unsigned int num)
{
  int len = strlen(name);
  regsym *rsym;

  /* check if register symbol already exists */
  rsym = no_case!=0 ? find_regsym_nc(name,len) : find_regsym(name,len);
  if (rsym!=NULL && !redef) {
    general_error(58,name);  /* register symbol redefined */
    return rsym;
  }

  if (rsym == NULL) {
    rsym = mymalloc(sizeof(regsym));
    rsym->reg_name = mystrdup(name);
    rsym->reg_type = type;
    rsym->reg_flags = flags;
    rsym->reg_num = num;
    add_regsym(rsym);
  }
  else {
    /* just update */
    rsym->reg_type = type;
    rsym->reg_flags = flags;
    rsym->reg_num = num;
  }

  return rsym;
}


/* remove an already defined register symbol from the hash table */
int undef_regsym(const char *name,int no_case,int type)
{
  regsym *rsym = no_case!=0 ?
                 find_regsym_nc(name,strlen(name)) :
                 find_regsym(name,strlen(name));

  if (rsym != NULL) {
    if (rsym->reg_type == type) {
      rem_hashentry(regsymhash,name,no_case);
      return 1;
    }
    else
      general_error(70,name);  /* register symbol has wrong type */
  }
  else
    general_error(69,name);  /* register does not exist */

  return 0;
}

#endif /* HAVE_REGSYMS */


int init_symbol(void)
{
  symhash = new_hashtable(SYMHTABSIZE);
#ifdef HAVE_REGSYMS
  regsymhash = new_hashtable(REGSYMHTSIZE);
#endif
  return 1;
}


void exit_symbol(void)
{
  if (debug) {
    if (symhash->collisions)
      fprintf(stderr,"*** %d symbol collisions!!\n",symhash->collisions);
#ifdef HAVE_REGSYMS
    if (regsymhash->collisions)
      fprintf(stderr,"*** %d register symbol collisions!!\n",regsymhash->collisions);
#endif
  }
}