ref: 47e8c646766773c8fda7e0fe44b10544c3f91695
dir: /cc1/stmt.c/
#include <stddef.h>
#include <inttypes.h>
#include <stdio.h>
#include "../inc/cc.h"
#include "cc1.h"
struct scase {
Symbol *label;
Node *expr;
struct scase *next;
};
struct caselist {
short nr;
Symbol *deflabel;
struct scase *head;
};
Symbol *curfun;
extern Node *convert(Node *np, Type *tp1, char iscast);
extern Node *iszero(Node *np), *eval(Node *np);
static void stmt(Symbol *lbreak, Symbol *lcont, Caselist *lswitch);
static Symbol *
label(char *s, char define)
{
Symbol *sym;
if ((sym = lookup(s, NS_LABEL)) != NULL) {
if (define) {
if (sym->isdefined)
error("label '%s' already defined", s);
sym->isdefined = 1;
}
return sym;
}
sym = install(s, NS_LABEL);
sym->isdefined = define;
return sym;
}
static void
stmtexp(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
Node *np = NULL;;
if (yytoken != ';') {
np = expr();
emitexp(np);
}
expect(';');
freetree(np);
}
static Node *
condition(void)
{
Node *np;
expect('(');
np = iszero(expr());
expect(')');
return np;
}
static void
While(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
Symbol *begin, *cond, *end;
Node *np;
begin = install("", NS_LABEL);
end = install("", NS_LABEL);
cond = install("", NS_LABEL);
expect(WHILE);
np = condition();
emitjump(cond, NULL);
emitbloop();
emitlabel(begin);
stmt(end, begin, lswitch);
emitlabel(cond);
emitjump(begin, np);
emiteloop();
emitlabel(end);
freetree(np);
}
static void
For(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
Symbol *begin, *cond, *end;
Node *econd, *einc, *einit;
begin = install("", NS_LABEL);
end = install("", NS_LABEL);
cond = install("", NS_LABEL);
expect(FOR);
expect('(');
einit = (yytoken != ';') ? expr() : NULL;
expect(';');
econd = (yytoken != ';') ? expr() : NULL;
expect(';');
einc = (yytoken != ')') ? expr() : NULL;
expect(')');
emitexp(einit);
emitjump(cond, NULL);
emitbloop();
emitlabel(begin);
stmt(end, begin, lswitch);
emitexp(einc);
emitlabel(cond);
emitjump(begin, econd);
emiteloop();
emitlabel(end);
freetree(einit);
freetree(econd);
freetree(einc);
}
static void
Dowhile(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
Symbol *begin, *end;
Node *np;
begin = install("", NS_LABEL);
end = install("", NS_LABEL);
expect(DO);
emitbloop();
emitlabel(begin);
stmt(end, begin, lswitch);
expect(WHILE);
np = condition();
emitjump(begin, np);
emiteloop();
emitlabel(end);
freetree(np);
}
static void
Return(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
Node *np;
Type *tp = curfun->type->type;
expect(RETURN);
np = (yytoken != ';') ? eval(expr()) : NULL;
expect(';');
if (!np) {
if (tp != voidtype)
warn(1, "function returning non void returns no value");
tp = voidtype;
} else if (np->type != tp) {
if (tp == voidtype)
warn(1, "function returning void returns a value");
else if ((np = convert(np, tp, 0)) == NULL)
error("incorrect type in return");
}
emitret(tp);
emitexp(np);
freetree(np);
}
static void
Break(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
expect(BREAK);
if (!lbreak)
error("break statement not within loop or switch");
emitjump(lbreak, NULL);
expect(';');
}
static void stmt(Symbol *lbreak, Symbol *lcont, Caselist *lswitch);
static void
Label(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
switch (yytoken) {
case IDEN: case TYPEIDEN:
emitlabel(label(yytext, 1));
next();
expect(':');
stmt(lbreak, lcont, lswitch);
break;
default:
unexpected();
}
}
static void
Continue(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
expect(CONTINUE);
if (!lcont)
error("continue statement not within loop");
emitjump(lcont, NULL);
expect(';');
}
static void
Goto(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
expect(GOTO);
if (yytoken != IDEN)
unexpected();
emitjump(label(yytext, 0), NULL);
next();
expect(';');
}
static void
Switch(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
Caselist lcase = {.nr = 0, .head = NULL, .deflabel = NULL};
struct scase *p, *next;
Node *cond;
Symbol *lcond;
void free(void *ptr);
expect(SWITCH);
expect ('(');
cond = expr();
if ((cond = convert(cond, inttype, 0)) == NULL)
error("incorrect type in switch statement");
expect (')');
lbreak = install("", NS_LABEL);
lcond = install("", NS_LABEL);
emitjump(lcond, NULL);
stmt(lbreak, lcont, &lcase);
emitlabel(lcond);
emitswitch(lcase.nr, cond);
for (p = lcase.head; p; p = next) {
emitcase(p->label, p->expr);
next = p->next;
freetree(p->expr);
free(p);
}
if (lcase.deflabel)
emitdefault(lcase.deflabel);
emitlabel(lbreak);
freetree(cond);
}
static void
Case(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
Node *np;
struct scase *pcase;
expect(CASE);
if (!lswitch)
error("case label not within a switch statement");
np = expr();
if ((np = convert(np, inttype, 0)) == NULL)
error("incorrect type in case statement");
expect(':');
pcase = xmalloc(sizeof(*pcase));
pcase->expr = np;
pcase->next = lswitch->head;
emitlabel(pcase->label = install("", NS_LABEL));
lswitch->head = pcase;
++lswitch->nr;
}
static void
Default(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
Symbol *ldefault = install("", NS_LABEL);
expect(DEFAULT);
expect(':');
emitlabel(ldefault);
lswitch->deflabel = ldefault;
}
static void
If(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
Symbol *end, *lelse;
Node *np;
lelse = install("", NS_LABEL);
expect(IF);
np = condition();
NEGATE(np, 1);
emitjump(lelse, np);
stmt(lbreak, lcont, lswitch);
if (accept(ELSE)) {
end = install("", NS_LABEL);
emitjump(end, NULL);
emitlabel(lelse);
stmt(lbreak, lcont, lswitch);
emitlabel(end);
} else {
emitlabel(lelse);
}
freetree(np);
}
void
compound(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
pushctx();
expect('{');
for (;;) {
switch (yytoken) {
case '}':
goto end_compound;
case TYPEIDEN:
if (ahead() == ':')
goto statement;
/* pass through */
case TYPE: case SCLASS: case TQUALIFIER:
decl();
break;
default:
statement:
stmt(lbreak, lcont, lswitch);
}
}
end_compound:
popctx();
expect('}');
return;
}
static void
stmt(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
{
void (*fun)(Symbol *lbreak, Symbol *lcont, Caselist *lswitch);
Node *np;
switch (yytoken) {
case '{': fun = compound; break;
case RETURN: fun = Return; break;
case WHILE: fun = While; break;
case FOR: fun = For; break;
case DO: fun = Dowhile; break;
case IF: fun = If; break;
case BREAK: fun = Break; break;
case CONTINUE: fun = Continue; break;
case GOTO: fun = Goto; break;
case SWITCH: fun = Switch; break;
case CASE: fun = Case; break;
case DEFAULT: fun = Default; break;
default: fun = stmtexp; break;
case TYPEIDEN: case IDEN:
fun = (ahead() == ':') ? Label : stmtexp;
break;
case '@':
next();
np = expr();
emitprint(np);
freetree(np);
return;
}
(*fun)(lbreak, lcont, lswitch);
}