ref: 40d91321c64a0ae0c5b7679b687b6c555fd4ecf0
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 getln(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 = getln(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; }