symbols.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

/*#@(#)symbols.c	4.1	Ultrix	7/17/90*/
/* Copyright (c) 1982 Regents of the University of California */

static char sccsid[] = "@(#)symbols.c 1.10 8/10/83";

static char rcsid[] = "$Header: symbols.c,v 1.4 84/03/27 10:24:18 linton Exp $";

/*
 * 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"

#ifndef public
typedef struct Symbol *Symbol;

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

/*
 * Symbol classes
 */

typedef enum {
    BADUSE, CONST, TYPE, VAR, ARRAY, 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
} 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 {
	int offset;		/* variable address */
	long iconval;		/* integer constant value */
	double fconval;		/* floating constant value */
	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 */
	    int unused : 13;
	    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_open;

Symbol program;
Symbol curfunc;

#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 nosource(f) (not (f)->symvalue.funcv.src)
#define isinline(f) ((f)->symvalue.funcv.inline)

#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 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->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;
}

/*
 * 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;
}

/*
 * 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 at the given recursive level.
 *
 * 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.
 */

public Symbol maketype(name, lower, upper)
String name;
long lower;
long upper;
{
    register Symbol s;

    s = newSymbol(identname(name, true), 0, TYPE, nil, nil);
    s->language = primlang;
    s->type = newSymbol(nil, 0, RANGE, s, nil);
    s->type->language = s->language;
    s->type->symvalue.rangev.lower = lower;
    s->type->symvalue.rangev.upper = upper;
    return s;
}

/*
 * These functions are now compiled inline.
 *
 * public String symname(s)
Symbol s;
{
    checkref(s);
    return ident(s->name);
}

 *
 * public Address codeloc(f)
Symbol f;
{
    checkref(f);
    if (not isblock(f)) {
	panic("codeloc: \"%s\" is not a block", ident(f->name));
    }
    return f->symvalue.funcv.beginaddr;
}
 *
 */

/*
 * 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 == FIELD or t->class == REF ) {
	    t = t->type;
	}
	if (t->class == TYPEREF) {
	    resolveRef(t);
	}
	while (t->class == TYPE or t->class == TAG) {
	    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 level(s)
Symbol s;
{
    checkref(s);
    return s->level;
}

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

/*
 * 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
 */

#define isglobal(s)		(s->level == 1)
#define islocaloff(s)		(s->level >= 2 and s->symvalue.offset < 0)
#define isparamoff(s)		(s->level >= 2 and s->symvalue.offset >= 0)
#define isreg(s)		(s->level < 0)

public Address address(s, frame)
Symbol s;
Frame frame;
{
    register Frame frp;
    register Address addr;
    register Symbol cur;

    checkref(s);
    if (not isactive(s->block)) {
	error("\"%s\" is not currently defined", symname(s));
    } else if (isglobal(s)) {
	addr = s->symvalue.offset;
    } else {
	frp = frame;
	if (frp == nil) {
	    cur = s->block;
	    while (cur != nil and cur->class == MODULE) {
		cur = cur->block;
	    }
	    if (cur == nil) {
		cur = whatblock(pc);
	    }