object.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

	    break;

	/*
	 * Source files.
	 */
	case N_SO:
	    n = identname(name, true);
	    enterSourceModule(n, (Address) np->n_value);
	    break;

	/*
	 * Textually included files.
	 */
	case N_SOL:
	    enterfile(name, (Address) np->n_value);
	    break;

	/*
	 * These symbols are assumed to have non-nil names.
	 */
	case N_GSYM:
	case N_FUN:
	case N_STSYM:
	case N_LCSYM:
	case N_RSYM:
	case N_PSYM:
	case N_LSYM:
	case N_SSYM:
	case N_LENG:
	    if (index(name, ':') == nil) {
		if (not warned) {
		    warned = true;
		    warning("old style symbol information found in \"%s\"",
			curfilename());
		}
	    } else {
		entersym(name, np);
	    }
	    break;

	case N_PC:
	case N_MOD2:
	    break;

	default:
	    printf("warning:  stab entry unrecognized: ");
	    if (name != nil) {
		printf("name %s,", name);
	    }
	    printf("ntype %2x, desc %x, value %x'\n",
		np->n_type, np->n_desc, np->n_value);
	    break;
    }
}

/*
 * Try to find the symbol that is referred to by the given name.
 * Since it's an external, we may want to follow a level of indirection.
 */

private Symbol findsym (n)
Name n;
{
    register Symbol r, s;

    find(s, n) where
	s->level == program->level and
	    (s->class == EXTREF or s->class == VAR or
	     s->class == PROC or s->class == FUNC)
    endfind(s);
    if (s != nil and s->class == EXTREF) {
	r = s->symvalue.extref;
	delete(s);
    } else {
	r = s;
    }
    return r;
}

/*
 * Check to see if a global _name is already in the symbol table,
 * if not then insert it.
 */

private check_global (name, np)
String name;
register struct nlist *np;
{
    register Name n;
    register Symbol t, u;

    if (not streq(name, "end")) {
	n = identname(name, true);
	if ((np->n_type&N_TYPE) == N_TEXT) {
	    t = findsym(n);
	    if (t == nil) {
		t = insert(n);
		t->language = findlanguage(".s");
		t->class = FUNC;
		t->type = t_int;
		t->block = curblock;
		t->level = program->level;
		t->symvalue.funcv.src = false;
		t->symvalue.funcv.inline = false;
	    }
	    if (t->class == VAR) {
		t->symvalue.offset = np->n_value;
	    } else {
		t->symvalue.funcv.beginaddr = np->n_value;
		newfunc(t, codeloc(t));
		findbeginning(t);
	    }
	} else if ((np->n_type&N_TYPE) == N_BSS) {
	    find(t, n) where
		t->class == COMMON
	    endfind(t);
	    if (t != nil) {
		u = (Symbol) t->symvalue.common.offset;
		while (u != nil) {
		    u->symvalue.offset = u->symvalue.common.offset+np->n_value;
		    u = u->symvalue.common.chain;
		}
            } else {
		check_var(np, n);
	    }
        } else {
	    check_var(np, n);
	}
    }
}

/*
 * Check to see if a namelist entry refers to a variable.
 * If not, create a variable for the entry.  In any case,
 * set the offset of the variable according to the value field
 * in the entry.
 */

private check_var (np, n)
struct nlist *np;
register Name n;
{
    register Symbol t;

    t = findsym(n);
    if (t == nil) {
	t = insert(n);
	t->language = findlanguage(".s");
	t->class = VAR;
	t->type = t_int;
	t->level = program->level;
	t->block = curblock;
    }
    t->symvalue.offset = np->n_value;
}

/*
 * Check to see if a local _name is known in the current scope.
 * If not then enter it.
 */

private check_local (name, np)
String name;
register struct nlist *np;
{
    register Name n;
    register Symbol t, cur;

    n = identname(name, true);
    cur = ((np->n_type&N_TYPE) == N_TEXT) ? curmodule : curblock;
    find(t, n) where t->block == cur endfind(t);
    if (t == nil) {
	t = insert(n);
	t->language = findlanguage(".s");
	t->type = t_int;
	t->block = cur;
	t->level = cur->level;
	if ((np->n_type&N_TYPE) == N_TEXT) {
	    t->class = FUNC;
	    t->symvalue.funcv.src = false;
	    t->symvalue.funcv.inline = false;
	    t->symvalue.funcv.beginaddr = np->n_value;
	    newfunc(t, codeloc(t));
	    findbeginning(t);
	} else {
	    t->class = VAR;
	    t->symvalue.offset = np->n_value;
	}
    }
}

/*
 * Check to see if a symbol corresponds to a object file name.
 * For some reason these are listed as in the text segment.
 */

private check_filename (name)
String name;
{
    register String mname;
    register integer i;
    register Symbol s;

    mname = strdup(name);
    i = strlen(mname) - 2;
    if (i >= 0 and mname[i] == '.' and mname[i+1] == 'o') {
	mname[i] = '\0';
	--i;
	while (mname[i] != '/' and i >= 0) {
	    --i;
	}
	s = insert(identname(&mname[i+1], true));
	s->language = findlanguage(".s");
	s->class = MODULE;
	s->symvalue.funcv.beginaddr = 0;
	findbeginning(s);
	if (curblock->class != PROG) {
	    exitblock();
	    if (curblock->class != PROG) {
		exitblock();
	    }
	}
	enterblock(s);
	curmodule = s;
    }
}

/*
 * Check to see if a symbol is about to be defined within an unnamed block.
 * If this happens, we create a procedure for the unnamed block, make it
 * "inline" so that tracebacks don't associate an activation record with it,
 * and enter it into the function table so that it will be detected
 * by "whatblock".
 */

public chkUnnamedBlock ()
{
    register Symbol s;
    static int bnum = 0;
    char buf[100];
    Address startaddr;

    if (nesting > 0 and addrstk[nesting] != NOADDR) {
	startaddr = (linep - 1)->addr;
	++bnum;
	sprintf(buf, "$b%d", bnum);
	s = insert(identname(buf, false));
	s->language = curlang;
	s->class = PROC;
	s->symvalue.funcv.src = false;
	s->symvalue.funcv.inline = true;
	s->symvalue.funcv.beginaddr = startaddr;
	enterblock(s);
	newfunc(s, startaddr);
	addrstk[nesting] = NOADDR;
    }
}

/*
 * Compilation unit.  C associates scope with filenames
 * so we treat them as "modules".  The filename without
 * the suffix is used for the module name.
 *
 * Because there is no explicit "end-of-block" mark in
 * the object file, we must exit blocks for the current
 * procedure and module.
 */

private enterSourceModule (n, addr)
Name n;
Address addr;
{
    register Symbol s;
    Name nn;
    String mname, suffix;

    mname = strdup(ident(n));
    if (rindex(mname, '/') != nil) {
	mname = rindex(mname, '/') + 1;
    }
    suffix = rindex(mname, '.');
    curlang = findlanguage(suffix);
    if (curlang == findlanguage(".f")) {
	strip_ = true;
    } 
    if (suffix != nil) {
	*suffix = '\0';
    }
    if (not (*language_op(curlang, L_HASMODULES))()) {
	if (curblock->class != PROG) {
	    exitblock();
	    if (curblock->class != PROG) {
		exitblock();
	    }
	}
	nn = identname(mname, true);
	if (curmodule == nil or curmodule->name != nn) {
	    s = insert(nn);
	    s->class = MODULE;
	    s->symvalue.funcv.beginaddr = 0;
	    findbeginning(s);
	} else {
	    s = curmodule;
	}
	s->language = curlang;
	enterblock(s);
	curmodule = s;
    }
    if (program->language == nil) {
	program->language = curlang;
    }
    warned = false;
    enterfile(ident(n), addr);
    initTypeTable();
}

/*
 * Allocate file and line tables and initialize indices.
 */

private allocmaps (nf, nl)
integer nf, nl;
{
    if (filetab != nil) {
	dispose(filetab);
    }
    if (linetab != nil) {
	dispose(linetab);
    }
    filetab = newarr(Filetab, nf);
    linetab = newarr(Linetab, nl);
    filep = filetab;
    linep = linetab;
}

/*
 * Add a file to the file table.
 *
 * If the new address is the same as the previous file address
 * this routine used to not enter the file, but this caused some
 * problems so it has been removed.  It's not clear that this in
 * turn may not also cause a problem.
 */

private enterfile (filename, addr)
String filename;
Address addr;
{
    filep->addr = addr;
    filep->filename = filename;
    filep->lineindex = linep - linetab;
    ++filep;
}

/*
 * Since we only estimated the number of lines (and it was a poor
 * estimation) and since we need to know the exact number of lines
 * to do a binary search, we set it when we're done.
 */

private setnlines ()
{
    nlhdr.nlines = linep - linetab;
}

/*
 * Similarly for nfiles ...
 */

private setnfiles ()
{
    nlhdr.nfiles = filep - filetab;
    setsource(filetab[0].filename);
}