ref: 1b6737c3ab2088041262077fadae13079b89fa88
dir: /src/cmd/as/parser.c/
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <setjmp.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <scc/cstd.h>
#include <scc/scc.h>
#include "as.h"
#define NARGS 20
#define NR_INPUTS 10
#define MAXLINE 100
struct input {
char *fname;
unsigned lineno;
FILE *fp;
};
int nerrors;
jmp_buf recover;
char yytext[INTIDENTSIZ+1];
int yytoken;
size_t yylen;
union yylval yylval;
static char *textp, *endp;
static int regmode;
static unsigned lineno;
static struct input inputs[NR_INPUTS], *isp = inputs;
static int
follow(int expect1, int expect2, int ifyes1, int ifyes2, int ifno)
{
int c;
if ((c = *++textp) == expect1)
return ifyes1;
if (c == expect2)
return ifyes2;
--textp;
return ifno;
}
static void
tok2str(void)
{
if ((yylen = endp - textp) > INTIDENTSIZ) {
error("token too big");
yylen = INTIDENTSIZ;
}
memcpy(yytext, textp, yylen);
yytext[yylen] = '\0';
textp = endp;
}
static int
iden(void)
{
int c;
char *p;
for ( ; c = *endp; ++endp) {
if (isalnum(c))
continue;
switch (c) {
case '\'':
case '_':
case '-':
case '.':
case '$':
continue;
default:
goto out_loop;
}
}
out_loop:
tok2str();
yylval.sym = lookup(yytext);
return (yylval.sym->flags & FREG) ? REG : IDEN;
}
static int
number(void)
{
int c, base = 10;
char *p;
TUINT n;
if (*endp == '0') {
base = 8;
++endp;
if (*endp == 'x') {
base = 16;
++endp;
}
}
for (n = 0; (c = *endp) && isxdigit(c); n += c) {
n *= base;
c -= '0';
if (n >= TUINT_MAX - c*base)
error("overflow in number");
endp++;
}
tok2str();
yylval.sym = tmpsym(n);
return NUMBER;
}
static int
character(void)
{
int c;
char *p;
while (*endp != '\'')
++endp;
return NUMBER;
}
static int
string(void)
{
int c;
size_t l;
char *s;
Symbol *sym = tmpsym(0);
for (++endp; *endp != '"'; ++endp)
;
++endp;
tok2str();
yylval.sym = sym;
/* FIXME: this memory is not freed ever */
l = yylen-2;
s = memcpy(xmalloc(l+1), yytext+1, l);
s[l] = '\0';
sym->name.buf = s;
return STRING;
}
static int
operator(void)
{
int c;
++endp;
if ((c = *textp) == '>')
c = follow('=', '>', LE, SHL, '>');
else if (c == '<')
c = follow('=', '<', GE, SHR, '>');
tok2str();
return c;
}
int
next(void)
{
int c;
while (isspace(*textp))
++textp;
endp = textp;
switch (c = *textp) {
case '\0':
strcpy(yytext, "EOS");
yylen = 3;
c = EOS;
break;
case '"':
c = string();
break;
case '\'':
c = character();
break;
case '%':
c = (regmode ? iden : operator)();
break;
case '_':
c = iden();
break;
default:
if (isdigit(c))
c = number();
else if (isalpha(c))
c = iden();
else
c = operator();
break;
}
return yytoken = c;
}
void
expect(int token)
{
if (yytoken != token)
unexpected();
next();
}
void
unexpected(void)
{
error("unexpected '%s'", yytext);
}
void
error(char *msg, ...)
{
va_list va;
struct input *ip;
assert(isp > inputs);
ip = &isp[-1];
va_start(va, msg);
fprintf(stderr, "as:%s:%u: ", ip->fname, ip->lineno);
vfprintf(stderr, msg, va);
putc('\n', stderr);
nerrors++;
va_end(va);
if (nerrors == 10)
die("as: too many errors");
longjmp(recover, 1);
}
Node *
getreg(void)
{
Node *np;
np = node(REG, NULL, NULL);
np->sym = yylval.sym;
np->addr = AREG;
expect(REG);
return np;
}
void
regctx(int mode)
{
regmode = mode;
}
Node *
operand(char **strp)
{
int imm = 0;
Node *np;
textp = *strp;
regctx(1);
switch (next()) {
case EOS:
np = NULL;
break;
case REG:
np = getreg();
break;
case STRING:
np = node(yytoken, NULL, NULL);
np->sym = yylval.sym;
np->addr = ASTR;
next();
break;
case '$':
next();
imm = 1;
default:
if (!imm) {
np = moperand();
} else {
np = expr();
np->addr = AIMM;
}
}
if (yytoken != ',' && yytoken != EOS)
error("trailing characters in expression '%s'", textp);
*strp = endp;
return np;
}
Node **
getargs(char *s)
{
Node **ap;
static Node *args[NARGS];
if (!s)
return NULL;
for (ap = args; ap < &args[NARGS-1]; ++ap) {
if ((*ap = operand(&s)) == NULL)
return args;
}
error("too many arguments in one instruction");
}
static char *
field(char **oldp, size_t *siz)
{
char *s, *t, *begin;
size_t n;
if ((begin = *oldp) == NULL)
return NULL;
for (s = begin; isspace(*s) && *s != '\t'; ++s)
;
if (*s == '\0' || *s == '#') {
*s = '\0';
return *oldp = NULL;
}
for (t = s; *t && *t != '\t'; ++t)
;
if (*t == '\t')
*t++ = '\0';
*siz -= begin - t;
*oldp = t;
while (t >= s && isspace(*t))
*t-- = '\0';
return (*s != '\0') ? s : NULL;
}
static int
validlabel(char *name)
{
int c;
while ((c = *name++) != '\0') {
if (isalnum(c))
continue;
switch (c) {
case '_':
case '-':
case '.':
case '$':
continue;
case ':':
if (*name != '\0')
return 0;
*--name = '\0';
continue;
default:
return 0;
}
}
return 1;
}
static int
extract(char *s, size_t len, struct line *lp)
{
int r = 0;
if (lp->label = field(&s, &len))
r++;
if (lp->op = field(&s, &len))
r++;
if (lp->args = field(&s, &len))
r++;
if (s && *s && *s != '#')
error("trailing characters at the end of the line");
if (lp->label && !validlabel(lp->label))
error("incorrect label name '%s'", lp->label);
return r;
}
static size_t
getline(FILE *fp, char buff[MAXLINE])
{
int c;
char *bp;
for (bp = buff; (c = getc(fp)) != EOF; *bp++ = c) {
if (c == '\n')
break;
if (c > UCHAR_MAX)
error("invalid character '%x'", c);
if (bp == &buff[MAXLINE-1])
error("line too long");
}
*bp = '\0';
return bp - buff;
}
int
nextline(struct line *lp)
{
struct input *ip;
size_t n;
static char buff[MAXLINE];
assert(isp > inputs);
repeat:
if (isp == inputs)
return 0;
ip = &isp[-1];
if (feof(ip->fp)) {
delinput();
goto repeat;
}
n = getline(ip->fp, buff);
if (++ip->lineno == 0)
die("as: %s: file too long", infile);
if (n == 0)
goto repeat;
if (extract(buff, n, lp) == 0)
goto repeat;
return 1;
}
void
addinput(char *fname)
{
FILE *fp;
if (isp == &inputs[NR_INPUTS])
die("as: too many included files");
if ((fp = fopen(fname, "r")) == NULL)
die("as: %s: %s", fname, strerror(errno));
isp->fname = xstrdup(fname);
isp->fp = fp;
isp->lineno = 0;
++isp;
}
int
delinput(void)
{
if (isp == inputs)
return EOF;
--isp;
if (fclose(isp->fp) == EOF)
die("as: %s: %s", isp->fname, strerror(errno));
free(isp->fname);
return 0;
}