Initial import

1 files changed, 134 insertions, 0 deletions

diff --git a/eval.c b/eval.c
new file mode 100644
index 0000000..80e9578
--- /dev/null
+++ b/eval.c
@@ -0,0 +1,134 @@
+#include <stddef.h>
+#include <stdint.h>
+#include "util.h"
+#include "decl.h"
+#include "emit.h"
+#include "eval.h"
+#include "expr.h"
+#include "token.h"
+#include "type.h"
+
+struct expression *
+eval(struct expression *expr)
+{
+	struct expression *l, *r, *c;
+	int op;
+
+	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 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.i = l->constant.f;
+			else if (typeprop(l->type) & PROPFLOAT && typeprop(expr->type) & PROPINT)
+				expr->constant.f = l->constant.i;
+			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;
+		if (l->kind != EXPRCONST)
+			break;
+		if (expr->binary.op == TLOR)
+			return !l->constant.i ? r : l;
+		if (expr->binary.op == TLAND)
+			return l->constant.i ? r : l;
+		if (r->kind != EXPRCONST)
+			break;
+		expr->kind = EXPRCONST;
+		op = expr->binary.op;
+#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
+		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;
+}