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#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include "util.h"
#include "backend.h"
#include "decl.h"
#include "eval.h"
#include "expr.h"
#include "token.h"
#include "type.h"
static void
binary(struct expression *expr, enum tokenkind op, struct expression *l, struct expression *r)
{
expr->kind = EXPRCONST;
#define F (1<<8)
#define S (2<<8)
if (typeprop(l->type) & PROPFLOAT)
op |= F;
else if (l->type->basic.issigned)
op |= S;
switch (op) {
case TMUL:
case TMUL|S: expr->constant.i = l->constant.i * r->constant.i; break;
case TMUL|F: expr->constant.f = l->constant.f * r->constant.f; break;
case TDIV: expr->constant.i = l->constant.i / r->constant.i; break;
case TDIV|S: expr->constant.i = (int64_t)l->constant.i / (int64_t)r->constant.i; break;
case TDIV|F: expr->constant.f = l->constant.f / r->constant.f; break;
case TMOD: expr->constant.i = l->constant.i % r->constant.i; break;
case TMOD|S: expr->constant.i = (int64_t)l->constant.i % (int64_t)r->constant.i; break;
case TADD:
case TADD|S: expr->constant.i = l->constant.i + r->constant.i; break;
case TADD|F: expr->constant.f = l->constant.f + r->constant.f; break;
case TSUB:
case TSUB|S: expr->constant.i = l->constant.i - r->constant.i; break;
case TSUB|F: expr->constant.f = l->constant.f - r->constant.f; break;
case TSHL:
case TSHL|S: expr->constant.i = l->constant.i << r->constant.i; break;
case TSHR: expr->constant.i = l->constant.i >> r->constant.i; break;
case TSHR|S: expr->constant.i = (int64_t)l->constant.i >> r->constant.i; break;
case TBAND:
case TBAND|S: expr->constant.i = l->constant.i & r->constant.i; break;
case TBOR:
case TBOR|S: expr->constant.i = l->constant.i | r->constant.i; break;
case TXOR:
case TXOR|S: expr->constant.i = l->constant.i ^ r->constant.i; break;
case TLESS: expr->constant.i = l->constant.i < r->constant.i; break;
case TLESS|S: expr->constant.i = (int64_t)l->constant.i < (int64_t)r->constant.i; break;
case TLESS|F: expr->constant.i = l->constant.f < r->constant.f; break;
case TGREATER: expr->constant.i = l->constant.i > r->constant.i; break;
case TGREATER|S: expr->constant.i = (int64_t)l->constant.i > (int64_t)r->constant.i; break;
case TGREATER|F: expr->constant.i = l->constant.f > r->constant.f; break;
case TLEQ: expr->constant.i = l->constant.i <= r->constant.i; break;
case TLEQ|S: expr->constant.i = (int64_t)l->constant.i <= (int64_t)r->constant.i; break;
case TLEQ|F: expr->constant.i = l->constant.f <= r->constant.f; break;
case TGEQ: expr->constant.i = l->constant.i >= r->constant.i; break;
case TGEQ|S: expr->constant.i = (int64_t)l->constant.i >= (int64_t)r->constant.i; break;
case TGEQ|F: expr->constant.i = l->constant.f >= r->constant.f; break;
case TEQL:
case TEQL|S: expr->constant.i = l->constant.i == r->constant.i; break;
case TEQL|F: expr->constant.i = l->constant.f == r->constant.f; break;
case TNEQ:
case TNEQ|S: expr->constant.i = l->constant.i != r->constant.i; break;
case TNEQ|F: expr->constant.i = l->constant.f != r->constant.f; break;
default:
fatal("internal error; unknown binary expression");
}
#undef F
#undef S
}
struct expression *
eval(struct expression *expr)
{
struct expression *l, *r, *c;
struct declaration *d;
switch (expr->kind) {
case EXPRIDENT:
if (expr->ident.decl->kind != DECLCONST)
break;
expr->kind = EXPRCONST;
expr->constant.i = intconstvalue(expr->ident.decl->value);
break;
case EXPRCOMPOUND:
d = mkdecl(DECLOBJECT, expr->type, LINKNONE);
d->value = mkglobal(NULL, true);
emitdata(d, expr->compound.init);
expr->kind = EXPRIDENT;
expr->ident.decl = d;
break;
case EXPRUNARY:
l = eval(expr->unary.base);
if (expr->unary.op != TBAND)
break;
switch (l->kind) {
case EXPRUNARY:
if (l->unary.op == TMUL)
expr = eval(l->unary.base);
break;
case EXPRSTRING:
l->ident.decl = stringdecl(l);
l->kind = EXPRIDENT;
expr->unary.base = l;
break;
}
break;
case EXPRCAST:
l = eval(expr->cast.e);
if (l->kind == EXPRCONST) {
expr->kind = EXPRCONST;
if (typeprop(l->type) & PROPINT && typeprop(expr->type) & PROPFLOAT)
expr->constant.f = l->constant.i;
else if (typeprop(l->type) & PROPFLOAT && typeprop(expr->type) & PROPINT)
expr->constant.i = l->constant.f;
else
expr->constant = l->constant;
} else if (l->type->kind == TYPEPOINTER && expr->type->kind == TYPEPOINTER) {
expr = l;
}
break;
case EXPRBINARY:
l = eval(expr->binary.l);
r = eval(expr->binary.r);
expr->binary.l = l;
expr->binary.r = r;
switch (expr->binary.op) {
case TADD:
if (r->kind == EXPRBINARY)
c = l, l = r, r = c;
if (r->kind != EXPRCONST)
break;
if (l->kind == EXPRCONST) {
binary(expr, expr->binary.op, l, r);
} else if (l->kind == EXPRBINARY && l->type->kind == TYPEPOINTER && l->binary.r->kind == EXPRCONST) {
if (l->binary.op == TADD || l->binary.op == TSUB) {
/* (P ± C1) + C2 -> P + (C2 ± C1) */
expr->binary.l = l->binary.l;
binary(expr->binary.r, l->binary.op, r, l->binary.r);
}
}
break;
/* TODO: TSUB pointer handling */
case TLOR:
if (l->kind != EXPRCONST)
break;
return l->constant.i ? l : r;
case TLAND:
if (l->kind != EXPRCONST)
break;
return l->constant.i ? r : l;
default:
if (l->kind != EXPRCONST || r->kind != EXPRCONST)
break;
binary(expr, expr->binary.op, l, r);
}
break;
case EXPRCOND:
l = expr->cond.t;
r = expr->cond.f;
c = eval(expr->cond.e);
if (c->kind != EXPRCONST)
break;
return eval(c->constant.i ? l : r);
}
return expr;
}
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