symbols.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

/*@(#)symbols.c	4.2	Ultrix	11/9/90*/

/************************************************************************
 *									*
 *			Copyright (c) 1986 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/************************************************************************
 *									*
 *			Modification History				*
 *									*
 *	011 - Modified which() for VAX FORTRAN.  f77 forces identifiers	*
 *	      to lower-case, while fort forces them to upper-case.  A   *
 *	      failed nametable search now results in further attempt(s),*
 *	      using all lower- and/or upper-case.			*
 *	      (Bob Neff, March 28, 1990)				*
 *									*
 *  010 - Fixed erroneous type mismatch.		*
 *		  (Lee Miller, Jan 24, 1990)			*
 *									*
 *  009	- Added support for vectors.							*
 *		  (L Miller, 18JAN90)									*
 *									*
 *	008 - Workaround for vcc bug.  Panic in several cases of bad	*
 *	      stab entries that could otherwise lead to infinite loops. *
 *	      Also remerged 4.3 changes for correct spacing.		*
 *	      (Jon Reeves, July 14, 1987)				*
 *									*
 *	007 - Bug fix for spr# ICA-01081.  Dbx used to panic when	*
 *	      doing conditional comparisons of string constants (eg.	*
 *	      stop at 18 if array[3] == "string" ).			*
 *	      Conditional string comparisons are not allowed, so dbx	*
 *	      now emits the appropriate error message (see binaryop()).	*
 *	      (vjh, May 23, 1986)					*
 *									*
 *	006 - Merged in 4.3 changes.					*
 *	      (vjh, April 29, 1986)					*
 *									*
 *	005 - Added support for jsb routines.  Also, converted		*
 *	      isinternal() to a macro.  Now use one of the "unused"	*
 *	      bits in the Symbol struct as a boolean jsb flag.		*
 *	      (vjh, August 9, 1985)					*
 *									*
 *	004 - Added new routine findproc(proc).				*
 *	      (vjh, July 17, 1985)					*
 *									*
 *	003 - Added a new Symclass:  NO_DSTMAP.  This is the class	*
 *	      given to symbols that won't map from a DST to a stab	*
 *	      (vjh, June 26, 1985)					*
 *									*
 *	002 - Updated all calls to findlanguage() to call with		*
 *	      LanguageName constant, rather than with a filename	*
 *	      suffix.							*
 *	      (vjh, June 22, 1985)					*
 *									*
 *	001 - Added new fields to the Symbol struct for supporting	*
 *	      register indirection/displacement modes:			*
 *	      symvalue.raddr.<fields>					*
 *	      (Victoria Holt, June 22, 1985)				*
 *									*
 ************************************************************************/

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#ifndef lint
static char *sccsid = "@(#)symbols.c	2.1	ULTRIX	4/24/89";
#endif not lint

/*
 * Symbol management.
 */

#include "defs.h"
#include "symbols.h"
#include "languages.h"
#include "printsym.h"
#include "tree.h"
#include "operators.h"
#include "eval.h"
#include "mappings.h"
#include "events.h"
#include "process.h"
#include "runtime.h"
#include "machine.h"
#include "names.h"
#include "main.h"

#ifndef public
typedef struct Symbol *Symbol;

#include "machine.h"
#include "names.h"
#include "languages.h"
#include "tree.h"

/*
 * Symbol classes
 */

typedef enum {
    BADUSE, CONST, TYPE, VAR, ARRAY, DYNARRAY, SUBARRAY, PTRFILE, RECORD, FIELD,
    PROC, FUNC, FVAR, REF, PTR, FILET, SET, RANGE, 
    LABEL, WITHPTR, SCAL, STR, PROG, IMPROPER, VARNT,
    FPROC, FFUNC, MODULE, TAG, COMMON, EXTREF, TYPEREF, NO_DSTMAP
} Symclass;

typedef enum { R_CONST, R_TEMP, R_ARG, R_ADJUST } Rangetype; 

struct Symbol {
    Name name;
    Language language;
    Symclass class : 8;
    Integer level : 8;
    Symbol type;
    Symbol chain;
    union {
	Node constval;		/* value of constant symbol */
	int offset;		/* variable address */
	long iconval;		/* integer constant value */
	double fconval;		/* floating constant value */
	int ndims;		/* no. of dimensions for dynamic/sub-arrays */
	struct {
	    unsigned int reg;
	    Boolean indirect;
	    int displacement;
	} raddr;
	struct {		/* field offset and size (both in bits) */
	    int offset;
	    int length;
	} field;
	struct {		/* common offset and chain; used to relocate */
	    int offset;         /* vars in global BSS */
	    Symbol chain;
	} common;
	struct {		/* range bounds */
            Rangetype lowertype : 16; 
            Rangetype uppertype : 16;  
	    long lower;
	    long upper;
	} rangev;
	struct {
	    int offset : 16;	/* offset for of function value */
	    Boolean src : 1;	/* true if there is source line info */
	    Boolean inline : 1;	/* true if no separate act. rec. */
	    Boolean intern : 1; /* internal calling sequence */
	    Boolean jsb : 1;	/* true if is jsb routine */
	    int unused : 12;
	    Address beginaddr;	/* address of function code */
	} funcv;
	struct {		/* variant record info */
	    int size;
	    Symbol vtorec;
	    Symbol vtag;
	} varnt;
	String typeref;		/* type defined by "<module>:<type>" */
	Symbol extref;		/* indirect symbol for external reference */
    } symvalue;
    Symbol block;		/* symbol containing this symbol */
    Symbol next_sym;		/* hash chain */
};

/*
 * Basic types.
 */

Symbol t_boolean;
Symbol t_char;
Symbol t_int;
Symbol t_real;
Symbol t_nil;
Symbol t_addr;
Symbol t_vquad;
Symbol t_vfloat;
Symbol t_vhex;
Symbol t_vint;
Symbol t_vmr;

Symbol program;
Symbol curfunc;

boolean showaggrs;

#define symname(s) ident(s->name)
#define codeloc(f) ((f)->symvalue.funcv.beginaddr)
#define isblock(s) (Boolean) ( \
    s->class == FUNC or s->class == PROC or \
    s->class == MODULE or s->class == PROG \
)
#define isroutine(s) (Boolean) ( \
    s->class == FUNC or s->class == PROC \
)

#define isinternal(s) (s->symvalue.funcv.intern)
#define jsbroutine(s) (s->symvalue.funcv.jsb)
#define nosource(f)   (not (f)->symvalue.funcv.src)
#define no_dstmap(f)  (f->class == NO_DSTMAP)
#define isinline(f)   ((f)->symvalue.funcv.inline)

#define isreg(s)		(s->level < 0)
#define isvreg(s)		(s->level == -4)

#include "tree.h"

/*
 * Some macros to make finding a symbol with certain attributes.
 */

#define find(s, withname) \
{ \
    s = lookup(withname); \
    while (s != nil and not (s->name == (withname) and

#define where /* qualification */

#define endfind(s) )) { \
	s = s->next_sym; \
    } \
}

#endif

/*
 * Symbol table structure currently does not support deletions.
 */

#define HASHTABLESIZE 2003

private Address regaddr();
private Symbol hashtab[HASHTABLESIZE];

#define hash(name) ((((unsigned) name) >> 2) mod HASHTABLESIZE)

/*
 * Allocate a new symbol.
 */

#define SYMBLOCKSIZE 100

typedef struct Sympool {
    struct Symbol sym[SYMBLOCKSIZE];
    struct Sympool *prevpool;
} *Sympool;

private Sympool sympool = nil;
private Integer nleft = 0;

public Symbol symbol_alloc()
{
    register Sympool newpool;

    if (nleft <= 0) {
	newpool = new(Sympool);
	bzero(newpool, sizeof(*newpool));
	newpool->prevpool = sympool;
	sympool = newpool;
	nleft = SYMBLOCKSIZE;
    }
    --nleft;
    return &(sympool->sym[nleft]);
}

public symbol_dump (func)
Symbol func;
{
    register Symbol s;
    register integer i;

    printf(" symbols in %s \n",symname(func));
    for (i = 0; i < HASHTABLESIZE; i++) {
	for (s = hashtab[i]; s != nil; s = s->next_sym) {
	    if (s->block == func) {
		psym(s);
	    }
	}
    }
}

/*
 * Free all the symbols currently allocated.
 */

public symbol_free()
{
    Sympool s, t;
    register Integer i;

    s = sympool;
    while (s != nil) {
	t = s->prevpool;
	dispose(s);
	s = t;
    }
    for (i = 0; i < HASHTABLESIZE; i++) {
	hashtab[i] = nil;
    }
    sympool = nil;
    nleft = 0;
}

/*
 * Create a new symbol with the given attributes.
 */

public Symbol newSymbol(name, blevel, class, type, chain)
Name name;
Integer blevel;
Symclass class;
Symbol type;
Symbol chain;
{
    register Symbol s;

    s = symbol_alloc();
    s->name = name;
    s->language = primlang;
    s->level = blevel;
    s->class = class;
    s->type = type;
    s->chain = chain;
    return s;
}

/*
 * Insert a symbol into the hash table.
 */

public Symbol insert(name)
Name name;
{
    register Symbol s;
    register unsigned int h;

    h = hash(name);
    s = symbol_alloc();
    s->name = name;
    s->next_sym = hashtab[h];
    hashtab[h] = s;
    return s;
}

/*
 * module lookup.
 */

public Symbol findmodule(name)
Name name;
{
    Symbol s;
    
	find(s, name) where ismodule(s) endfind(s);
    return s;
}

/*
 * Symbol lookup.
 */

public Symbol lookup(name)
Name name;
{
    register Symbol s;
    register unsigned int h;

    h = hash(name);
    s = hashtab[h];
    while (s != nil and s->name != name) {
	s = s->next_sym;
    }
    return s;
}

/* Routine to lookup procedure "proc" in the symbol table.
 */
public Symbol findproc(proc)
String proc;
{
    Name n;
    Symbol s;

    n = identname(proc, false);
    find(s, n) where isroutine(s) endfind(s);
    return s;
}

/*
 * Delete a symbol from the symbol table.
 */

public delete (s)
Symbol s;
{
    register Symbol t;
    register unsigned int h;

    h = hash(s->name);
    t = hashtab[h];
    if (t == nil) {
	panic("delete of non-symbol '%s'", symname(s));
    } else if (t == s) {
	hashtab[h] = s->next_sym;
    } else {
	while (t->next_sym != s) {
	    t = t->next_sym;
	    if (t == nil) {
		panic("delete of non-symbol '%s'", symname(s));
	    }
	}
	t->next_sym = s->next_sym;
    }
}

/*
 * Dump out all the variables associated with the given
 * procedure, function, or program associated with the given stack frame.
 *
 * This is quite inefficient.  We traverse the entire symbol table
 * each time we're called.  The assumption is that this routine
 * won't be called frequently enough to merit improved performance.
 */

public dumpvars(f, frame)
Symbol f;
Frame frame;
{
    register Integer i;
    register Symbol s;

    for (i = 0; i < HASHTABLESIZE; i++) {
	for (s = hashtab[i]; s != nil; s = s->next_sym) {
	    if (container(s) == f) {
		if (should_print(s)) {
		    printv(s, frame);
		    putchar('\n');
		} else if (s->class == MODULE) {
		    dumpvars(s, frame);
		}
	    }
	}
    }
}

/*
 * Create a builtin type.
 * Builtin types are circular in that btype->type->type = btype.
 */

private Symbol maketype(name, lower, upper)
String name;
long lower;
long upper;
{
    register Symbol s;
    Name n;

    if (name == nil) {
	n = nil;
    } else {
	n = identname(name, true);
    }
    s = insert(n);
    s->language = primlang;
    s->level = 0;
    s->class = TYPE;
    s->type = nil;
    s->chain = nil;
    s->type = newSymbol(nil, 0, RANGE, s, nil);
    s->type->symvalue.rangev.lower = lower;
    s->type->symvalue.rangev.upper = upper;
    return s;
}

/*
 * Create the builtin symbols.
 */

public symbols_init ()
{
    Symbol s;

    t_boolean = maketype("$boolean", 0L, 1L);
    t_int = maketype("$integer", 0x80000000L, 0x7fffffffL);
    t_char = maketype("$char", 0L, 255L);
    t_real = maketype("$real", 8L, 0L);
    t_nil = maketype("$nil", 0L, 0L);
    t_addr = insert(identname("$address", true));
    t_addr->language = primlang;
    t_addr->level = 0;
    t_addr->class = TYPE;
    t_addr->type = newSymbol(nil, 1, PTR, t_int, nil);
    s = insert(identname("true", true));
    s->class = CONST;
    s->type = t_boolean;
    s->symvalue.constval = build(O_LCON, 1L);
    s->symvalue.constval->nodetype = t_boolean;
    s = insert(identname("false", true));
    s->class = CONST;
    s->type = t_boolean;
    s->symvalue.constval = build(O_LCON, 0L);
    s->symvalue.constval->nodetype = t_boolean;
    /* Create vector register element type */
	if(vectorcapable) {
    	t_vmr = maketype("$vmr", 0L, 1L);
    	t_vquad = maketype("$vquad", 8L, 0L);
    	t_vfloat = maketype("vfloat", 8L, 0L);
    	t_vhex = maketype("vhex", 8L, 0L);
    	t_vint = maketype("vint", 8L, 0L);
	}
}

/*
 * Reduce type to avoid worrying about type names.
 */

public Symbol rtype(type)
Symbol type;
{
    register Symbol t;

    t = type;
    if (t != nil) {
	if (t->class == VAR or t->class == CONST or
	    t->class == FIELD or t->class == REF
	) {
	    assert(t != t->type);
	    t = t->type;
	}
	if (t->class == TYPEREF) {
	    resolveRef(t);
	}
	while (t->class == TYPE or t->class == TAG) {
	    assert(t != t->type);
	    t = t->type;
	    if (t->class == TYPEREF) {
		resolveRef(t);
	    }
	}
    }
    return t;
}

/*
 * Find the end of a module name.  Return nil if there is none
 * in the given string.
 */

private String findModuleMark (s)
String s;
{
    register char *p, *r;
    register boolean done;

    p = s;
    done = false;
    do {
	if (*p == ':') {
	    done = true;
	    r = p;
	} else if (*p == '\0') {
	    done = true;
	    r = nil;
	} else {
	    ++p;
	}
    } while (not done);
    return r;
}

/*
 * Resolve a type reference by modifying to be the appropriate type.
 *
 * If the reference has a name, then it refers to an opaque type and
 * the actual type is directly accessible.  Otherwise, we must use
 * the type reference string, which is of the form "module:{module:}name".
 */

public resolveRef (t)
Symbol t;
{
    register char *p;
    char *start;
    Symbol s, m, outer;
    Name n;

    if (t->name != nil) {
	s = t;
    } else {
	start = t->symvalue.typeref;
	outer = program;
	p = findModuleMark(start);
	while (p != nil) {
	    *p = '\0';
	    n = identname(start, true);
	    find(m, n) where m->block == outer endfind(m);
	    if (m == nil) {
		p = nil;
		outer = nil;
		s = nil;
	    } else {
		outer = m;
		start = p + 1;
		p = findModuleMark(start);
	    }
	}
	if (outer != nil) {
	    n = identname(start, true);
	    find(s, n) where s->block == outer endfind(s);
	}
    }
    if (s != nil and s->type != nil) {
	t->name = s->type->name;
	t->class = s->type->class;
	t->type = s->type->type;
	t->chain = s->type->chain;
	t->symvalue = s->type->symvalue;
	t->block = s->type->block;
    }
}

public integer regnum (s)
Symbol s;
{
    integer r;

    checkref(s);
    if (s->level < 0) {
	r = s->symvalue.offset;
    } else {
	r = -1;
    }
    return r;
}

public Symbol container(s)
Symbol s;
{
    checkref(s);
    return s->block;
}

public Node constval(s)
Symbol s;
{
    checkref(s);
    if (s->class != CONST) {
	error("[internal error: constval(non-CONST)]");
    }
    return s->symvalue.constval;
}

/*
 * Return the object address of the given symbol.
 *
 * There are the following possibilities:
 *
 *	globals		- just take offset
 *	locals		- take offset from locals base
 *	arguments	- take offset from argument base
 *	register	- offset is register number