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b.c
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b.c
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#include "def.h"
#include "b.h"
void extdef(void);
void enddef(void);
void func(void);
void decl(int type);
void stmt(void);
Node *expr(void);
Node *pexpr(void);
Node *tree(void);
Node *node(int op);
int build(int op);
void genxpr(Node *n, int lv);
void cjmp(Node *n, int l);
void jmp(int l);
void errflush(int t);
Sym *lookup(char *s);
int token(void);
int number(void);
int getcc(void);
int getstr(void);
int getchr(void);
void ungetchr(int c);
int loc;
int prevfix;
FILE *tmpfil1, *tmpfil2;
int opdope[] = {
#define X(def, str, prec, flag) prec<<6 | flag,
OPS
#undef X
};
char *opstr[] = {
#define X(def, str, prec, flag) str,
OPS
#undef X
};
unsigned char ctab[256];
int nerrors;
int eof;
int lineno = 1;
int peekc[2];
int npeek;
int peektok = -1;
Sym symtab[NSYMS];
int symsused;
Sym *sym;
word val;
int brklab;
int deflab;
int pop;
int stklab;
int stack;
int setstack;
Node nodes[NNODES];
int nalloc;
Node *nst[NNSTACK];
Node **np;
SwCase swtab[NSWITCH];
SwCase *swp;
void
panic(char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
va_end(ap);
exit(1);
}
void
err(char *fmt, ...)
{
va_list ap;
nerrors++;
va_start(ap, fmt);
fprintf(stderr, "%d error: ", lineno);
vfprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
va_end(ap);
}
void
uputn(FILE *f, uint64_t n, int b)
{
if(n/b)
uputn(f, n/b, b);
putc(n%b + '0', f);
}
void
putn(FILE *f, int64_t n, int b)
{
if(n < 0) {
putchar('-');
n = -n;
}
uputn(f, n, b);
}
void
fprf(FILE *f, char *fmt, ...)
{
char *s;
int n;
int nfmt;
word w;
word wflg;
int b;
va_list ap;
va_start(ap, fmt);
for(; *fmt; fmt++) {
if(*fmt != '%')
putc(*fmt, f);
else {
cont: fmt++;
nfmt = 0;
switch(*fmt) {
case 's':
s = va_arg(ap, char*);
while(*s)
putc(*s++, f);
break;
case 'n':
s = va_arg(ap, char*);
if(DECOR)
putc('_', f);
n = NCPS;
while(n-- && *s)
putc(*s++, f);
break;
case 'O':
if(OCTFMT)
putc('0', f);
case 'o':
b = 8;
goto num;
case 'D':
if(DECFMT)
nfmt = 1;
case 'd':
b = 10;
num:
if(wflg && sizeof(word) > sizeof(int)) {
w = va_arg(ap, word);
uputn(f, w, b);
} else {
n = va_arg(ap, int);
putn(f, n, b);
}
if(nfmt)
putc('.', f);
break;
case 'l':
putc('l', f);
b = 10;
wflg = 0;
goto num;
case 'w':
wflg = 1;
goto cont;
default:
putc(*fmt, f);
}
}
wflg = 0;
}
va_end(ap);
}
void
keyw(char *s, int t)
{
char *bp, buf[NCPS];
int i;
Sym *sp;
i = NCPS;
bp = buf;
while(i--)
if((*bp++ = *s++) == '\0')
s--;
sp = lookup(buf);
sp->type = KeyType;
sp->val = t;
}
void
dumptbl(void)
{
Sym *s;
for(s = symtab; s < &symtab[NSYMS]; s++)
if(s->name[0])
prf("%n %d %d\n", s->name, s->type, s->val);
}
int
main(/*int argc, char *argv[]*/)
{
int c;
tmpfil1 = fopen("/tmp/b.tmp1", "w+");
if(tmpfil1 == nil)
panic("can't open file /tmp/b.tmp1");
tmpfil2 = fopen("/tmp/b.tmp2", "w+");
if(tmpfil2 == nil)
panic("can't open file /tmp/b.tmp2");
keyw("auto", Auto);
keyw("extrn", Extern);
keyw("goto", Goto);
keyw("return", Return);
keyw("if", If);
keyw("while", While);
keyw("else", Else);
keyw("switch", Switch);
keyw("case", Case);
keyw("break", Break);
keyw("default", Default);
loc = 1;
prologue();
while(!eof) {
extdef();
enddef();
}
/* strings - in data segment */
datasym(nil);
rewind(tmpfil1);
while(c = getc(tmpfil1), c != EOF)
putchar(c);
putchar('\n');
epilogue();
rewind(tmpfil2);
while(c = getc(tmpfil2), c != EOF)
putchar(c);
wdconst(0);
return nerrors != 0;
}
void
extdef(void)
{
char *s;
int t;
int i, n;
t = token();
if(t == 0 || t == Semi)
return;
if(t != Name)
goto syntax;
sym->type = Extern;
s = sym->name;
global(s);
switch(t = token()) {
/* Single word */
case Semi:
bsssym(s);
skip(NBPW);
return;
case Const:
datasym(s);
wdconst(val);
return;
case String:
datasym(s);
wdlab(val);
fixup(s, 0);
return;
case Name:
datasym(s);
wdsym(sym->name);
fixup(s, 0);
return;
/* Vector */
case LBrack:
t = token();
n = 0;
if(t == Const) {
n = val;
t = token();
}
if(t != RBrack)
goto syntax;
datasym(s);
wdlab(0);
fixup(s, 0);
t = token();
if(t == Semi) {
bsssym(nil);
skip(n*NBPW);
return;
}
datasym(nil);
while(t == Const || t == String || t == Name) {
switch(t) {
case Const:
wdconst(val);
break;
case String:
i = loc++;
label(i);
wdlab(val);
fixup(nil, i);
break;
case Name:
i = loc++;
label(i);
wdsym(sym->name);
fixup(nil, i);
break;
}
n--;
t = token();
if(t == Semi)
break;
if(t != Comma)
goto syntax;
t = token();
}
if(n > 0)
skip(n*NBPW);
return;
/* Function */
case LParen:
datasym(s);
wdlab(0);
func();
return;
}
syntax:
err("Definition syntax");
errflush(t);
}
void
func(void)
{
Sym *s;
/* Stack layout:
* auton
* ....
* auto0
* argn
* 3 ....
* 2 arg0
* 1 return address
* 0 old fp <- fp
*/
stack = 2*NBPW; /* address of first variable */
stklab = loc++;
textsym();
decl(Param);
setstack = 1;
stmt();
etcop(9);
setlab(stklab, stack);
for(s = symtab; s < &symtab[NSYMS]; s++)
if(s->name[0] != '\0' && s->type == 0)
err("%.8s undefined", s->name);
}
void
enddef(void)
{
Sym *s;
for(s = symtab; s < &symtab[NSYMS]; s++)
if(s->type != KeyType)
memset(s, 0, sizeof(Sym));
putchar('\n');
}
void
decl(int type)
{
int t;
while(t = token(), t == Name) {
if(sym->type != 0)
err("Redeclared %.8s", sym->name);
sym->type = type;
if(type == Param || type == Auto) {
sym->type = Auto;
sym->val = stack;
stack += NBPW;
}
t = token();
if(type == Auto) {
/* Two ways to declare vectors */
if(t == LBrack) {
opint("y", sym->val);
t = token();
if(t == Const) {
stack += val*NBPW;
t = token();
}
if(t != RBrack)
goto syntax;
t = token();
} else if(t == Const) {
opint("y", sym->val);
stack += val*NBPW;
t = token();
}
}
if(t != Comma)
break;
}
if(type == Param && t != RParen)
goto syntax;
if(type != Param && t != Semi)
goto syntax;
return;
syntax:
err("Declaration syntax");
errflush(t);
}
void
setop(void)
{
if(setstack) {
oplab("s", stklab);
setstack = 0;
pop = 0;
}
}
void
stmt(void)
{
int l1, l2, l3;
int c, t, i;
SwCase *ssw;
stmt:
t = token();
switch(t) {
case 0:
err("Unexpected EOF");
return;
case RBrace:
peektok = t;
case Semi:
return;
case LBrace:
while(t = token(), t != RBrace) {
if(eof) {
err("Expected }");
break;
}
peektok = t;
stmt();
}
return;
case Keyword:
switch(val) {
case Auto:
setstack = 1;
case Extern:
decl(val);
goto stmt;
case Return:
if(peektok = token(), peektok == LParen) {
setop();
genxpr(pexpr(), 0);
pop = 1;
etcop(7);
goto semi;
}
etcop(9);
goto semi;
case Goto:
setop();
genxpr(expr(), 0);
pop = 1;
etcop(6);
goto semi;
case If:
setop();
cjmp(pexpr(), l1=loc++);
pop = 1;
stmt();
t = token();
if(t == Keyword && val == Else) {
jmp(l2=loc++);
label(l1);
stmt();
label(l2);
} else {
peektok = t;
label(l1);
}
return;
case While:
l1 = brklab;
brklab = loc++;
label(l2 = loc++);
setop();
cjmp(pexpr(), brklab);
pop = 1;
stmt();
jmp(l2);
label(brklab);
brklab = l1;
return;
case Switch:
l1 = brklab;
brklab = loc++;
setop();
/* TODO: actually expr(),
* but that might not parse nicely */
genxpr(pexpr(), 0);
pop = 1;
oplab("z", l2=loc++);
ssw = swp;
if(swp == nil)
swp = swtab;
l3 = deflab;
deflab = 0;
stmt();
jmp(brklab);
if(deflab == 0)
deflab = brklab;
c = 0;
while(swp > ssw && swp > swtab) {
c++;
swp--;
}
/* this wouldn't be so bad but the PDP-11 runtime
* doesn't handle this case */
if(c == 0)
err("No cases in switch");
label(l2);
wdint(c);
for(i = 0; i < c; i++) {
wdconst((word)swp[i].val);
wdlab(swp[i].lab);
}
/* Fall through here if no case has been found.
* Put a jump to the default case if there is one. */
if(deflab != brklab)
jmp(deflab);
label(brklab);
deflab = l3;
brklab = l1;
return;
case Case:
if(t = token(), t != Const)
goto syntax;
if(t = token(), t != Colon)
goto syntax;
if(swp == nil) {
err("Not in switch");
goto stmt;
}
/* TODO: check size */
swp->val = val;
swp->lab = loc;
swp++;
label(loc++);
goto stmt;
case Break:
if(brklab == 0)
err("Nothing to break from");
jmp(brklab);
goto semi;
case Default:
if(swp == nil)
err("Not in switch");
if(deflab)
err("default case already defined");
if(t = token(), t != Colon)
goto syntax;
label(deflab = loc++);
goto stmt;
}
case Name:
c = getchr();
if(c != ':') {
ungetchr(c);
break;
}
if(sym->type != 0) {
err("Redefinition");
goto stmt;
}
sym->type = Intern;
if(sym->val == 0)
sym->val = loc++;
clab(sym->val);
setstack = 1;
goto stmt;
}
peektok = t;
setop();
genxpr(expr(), 0);
pop = 1;
semi: t = token();
if(t != Semi)
goto syntax;
return;
syntax:
err("Statement syntax %d", t);
errflush(t);
goto stmt;
}
Node*
pexpr(void)
{
int t;
Node *n;
if(t = token(), t != LParen)
goto syntax;
n = expr();
if(t = token(), t != RParen)
goto syntax;
return n;
syntax:
err("Statement syntax");
errflush(t);
return nil;
}
Node*
expr(void)
{
np = nst;
nalloc = 0;
return tree();
}
Node*
tree(void)
{
int o, t;
int opst[100];
int *op;
Node *n;
int p, ps;
int and;
op = opst;
*op = 0;
and = 0;
next:
t = token();
switch(t) {
/* Leaves */
case Name:
n = node(t);
n->s = sym;
if(sym->type == 0) {
t = token();
if(t == LParen)
sym->type = Extern;
else
if(sym->val == 0)
sym->val = loc++;
peektok = t;
}
goto opnd;
case Const:
n = node(t);
n->w = val;
goto opnd;
case String:
n = node(t);
n->l = val;
opnd:
/* TODO: check space */
*np++ = n;
if(and)
goto syntax;
and = 1;
goto next;
/* Unary ops */
case Preinc:
if(and) {
t = Postinc;
goto opstk;
}
goto un;
case Predec:
if(and) {
t = Postdec;
goto opstk;
}
goto un;
case Not:
if(and) goto syntax;
goto un;
case Minus:
if(!and) t = Neg;
goto un;
case And:
if(!and) t = Amp;
goto un;
case Times:
if(!and) t = Star;
goto un;
/* Vector addressing */
case LBrack:
if(!and)
goto syntax;
if(n = tree(), n == nil)
goto flsh;
t = token();
if(t != RBrack)
goto syntax;
*np++ = n;
if(build(Vector)) goto flsh;
goto next;
case LParen:
if(and) {
/* Function call */
peektok = token();
if(peektok == RParen) {
peektok = -1;
n = nil;
} else {
if(n = tree(), n == nil)
goto flsh;
if(t = token(), t != RParen)
goto syntax;
}
*np++ = n;
if(build(Call)) goto flsh;
goto next;
} else {
/* Sub-expression */
if(n = tree(), n == nil)
goto flsh;
if(t = token(), t != RParen)
goto syntax;
goto opnd;
}
}
/* Everything else should be binary */
if(and == 0)
goto syntax;
un:
and = 0;
opstk:
p = opdope[t]>>6;
ps = opdope[*op]>>6;
if(p > ps || p == ps && opdope[t]&R) {
*++op = t;
goto next;
}
if(o = *op--, o == 0) {
peektok = t;
return *--np;
}
if(build(o)) goto flsh;
goto opstk;
syntax:
err("Expression syntax");
flsh: errflush(t);
return nil;
}
Node*
node(int op)
{
Node *n;
n = &nodes[nalloc++];
/* TODO: check space */
n->op = op;
n->n1 = nil;
n->n2 = nil;
return n;
}
int
build(int op)
{
Node *n, *n1, *n2;
if(op == Vector) {
if(build(Plus)) return 1;
op = Star;
}
n2 = nil;
if(opdope[op] & Bin)
n2 = *--np;
n1 = *--np;
switch(op) {
case Quest:
if(n2->op != Colon) {
err(": Expected");
return 1;
}
break;
case Star:
if(n1->op == Amp) {
*np++ = n1->n1;
return 0;
}
break;
case Amp:
if(n1->op == Star) {
*np++ = n1->n1;
return 0;
}
if(n1->op != Name) {
err("Illegal lvalue");
return 1;
}
}
if(opdope[op] & Lval)
if(n1->op != Star && n1->op != Name) {
err("Illegal lvalue");
return 1;
}
n = node(op);
n->n1 = n1;
n->n2 = n2;
*np++ = n;
return 0;
}
void
genleaf(Node *n, int lv)
{
static char *a[] = { "a", "ia", "va", "iva" };
static char *x[] = { "x", "ix", "vx", "ivx" };
static char *c[] = { "c", "ic" };
Sym *s;
int i;
i = pop;
pop = 0;
switch(n->op) {
case Name:
s = n->s;
switch(s->type) {
case Extern:
opsym(x[lv<<1|i], s->name);
break;
case 0: /* undefined labels */
case Intern:
oplab(x[lv<<1|i], (int)s->val);
break;
case Auto:
opint(a[lv<<1|i], (int)s->val);
break;
default:
panic("invalid type %d\n", s->type);
}
return;
case Const:
opconst(c[i], n->w);
return;
case String:
oplab(x[2|i], n->l);
return;
}
}
void
genxpr(Node *n, int lv)
{
int op, l1, l2;
Node *n1, *n2;
if(n == nil) return;
op = n->op;
n1 = n->n1;
n2 = n->n2;
switch(n->op) {
case Name:
case Const:
case String:
genleaf(n, lv);
return;
case Amp:
if(n1->op == Name)
genleaf(n1, 1);
return;
case Call:
genxpr(n1, 0);
if(n2 == nil) {
etcop(1);
return;
}
etcop(2);
for(; n2->op == Comma; n2 = n2->n2)
genxpr(n2->n1, 0);
genxpr(n2, 0);
etcop(3);
return;
case Comma:
for(; n->op == Comma; n = n->n2) {
genxpr(n->n1, 0);
pop = 1;
}
genxpr(n, 0);
return;
case Quest:
cjmp(n1, l1=loc++);
pop = 1;
genxpr(n2->n1, lv);
jmp(l2=loc++);
label(l1);
pop = 1;
genxpr(n2->n2, lv);
label(l2);
return;
case Star:
if(lv) {
genxpr(n1, 0);
return;
}
if(n1->op == Plus) {
n->op = Vector;
n->n1 = n1->n1;
n->n2 = n1->n2;
genxpr(n, 0);
return;
}
}
genxpr(n1, (opdope[op]&Lval)!=0);
genxpr(n2, 0);
if(op < Vector)
err("UNKNOWN OP(%s)\n", opstr[op]);
else if(op == Vector)
etcop(4);
else if(op <= Div)
binop(op-Assign+1);
else if(op <= ADiv)
binop(op-AOr+0102);
else if(op <= Postdec)
unaop(op-Amp+1);
}
/* jump to label l if condition is false,
* fall through otherwise. */
void
cjmp(Node *n, int l)
{
int l1, l2;
/* error */
if(n == nil)
return;
switch(n->op) {
case And:
cjmp(n->n1, l);
cjmp(n->n2, l);
return;
case Or:
cjmp(n->n1, l1=loc++);
jmp(l2=loc++);
label(l1);
cjmp(n->n2, l);
label(l2);
return;
case Not: