static struct block *postfix_expression(struct block *block)
{
struct var root;
block = primary_expression(block);
root = block->expr;
while (1) {
const struct member *field;
const struct typetree *type;
struct var expr, copy, *arg;
struct token tok;
int i, j;
switch ((tok = peek()).token) {
case '[':
do {
/* Evaluate a[b] = *(a + b). The semantics of pointer arithmetic
* takes care of multiplying b with the correct width. */
consume('[');
block = expression(block);
root = eval_expr(block, IR_OP_ADD, root, block->expr);
root = eval_deref(block, root);
consume(']');
} while (peek().token == '[');
break;
case '(':
type = root.type;
if (is_pointer(root.type) && is_function(root.type->next))
type = type_deref(root.type);
else if (!is_function(root.type)) {
error("Expression must have type pointer to function, was %t.",
root.type);
exit(1);
}
consume('(');
arg = calloc(nmembers(type), sizeof(*arg));
for (i = 0; i < nmembers(type); ++i) {
if (peek().token == ')') {
error("Too few arguments, expected %d but got %d.",
nmembers(type), i);
exit(1);
}
block = assignment_expression(block);
arg[i] = block->expr;
/* todo: type check here. */
if (i < nmembers(type) - 1) {
consume(',');
}
}
while (is_vararg(type) && peek().token != ')') {
consume(',');
arg = realloc(arg, (i + 1) * sizeof(*arg));
block = assignment_expression(block);
arg[i] = block->expr;
i++;
}
consume(')');
for (j = 0; j < i; ++j)
param(block, arg[j]);
free(arg);
root = eval_call(block, root);
break;
case '.':
consume('.');
tok = consume(IDENTIFIER);
field = find_type_member(root.type, tok.strval);
if (!field) {
error("Invalid field access, no member named '%s'.",
tok.strval);
exit(1);
}
root.type = field->type;
root.offset += field->offset;
break;
case ARROW:
consume(ARROW);
tok = consume(IDENTIFIER);
if (is_pointer(root.type) && is_struct_or_union(root.type->next)) {
field = find_type_member(type_deref(root.type), tok.strval);
if (!field) {
error("Invalid field access, no member named '%s'.",
tok.strval);
exit(1);
}
/* Make it look like a pointer to the field type, then perform
* normal dereferencing. */
root.type = type_init(T_POINTER, field->type);
root = eval_deref(block, root);
root.offset = field->offset;
} else {
error("Invalid field access.");
exit(1);
}
break;
case INCREMENT:
consume(INCREMENT);
copy = create_var(root.type);
eval_assign(block, copy, root);
expr = eval_expr(block, IR_OP_ADD, root, var_int(1));
eval_assign(block, root, expr);
root = copy;
break;
case DECREMENT:
consume(DECREMENT);
copy = create_var(root.type);
eval_assign(block, copy, root);
expr = eval_expr(block, IR_OP_SUB, root, var_int(1));
eval_assign(block, root, expr);
root = copy;
break;
default:
block->expr = root;
return block;
}
}
}
static struct block *unary_expression(struct block *block)
{
struct var value;
switch (peek().token) {
case '&':
consume('&');
block = cast_expression(block);
block->expr = eval_addr(block, block->expr);
break;
case '*':
consume('*');
block = cast_expression(block);
block->expr = eval_deref(block, block->expr);
break;
case '!':
consume('!');
block = cast_expression(block);
block->expr = eval_expr(block, IR_OP_EQ, var_int(0), block->expr);
break;
case '~':
consume('~');
block = cast_expression(block);
block->expr = eval_expr(block, IR_NOT, block->expr);
break;
case '+':
consume('+');
block = cast_expression(block);
block->expr.lvalue = 0;
break;
case '-':
consume('-');
block = cast_expression(block);
block->expr = eval_expr(block, IR_OP_SUB, var_int(0), block->expr);
break;
case SIZEOF: {
struct typetree *type;
struct block *head = cfg_block_init(), *tail;
consume(SIZEOF);
if (peek().token == '(') {
switch (peekn(2).token) {
case FIRST(type_name):
consume('(');
type = declaration_specifiers(NULL);
if (peek().token != ')') {
type = declarator(type, NULL);
}
consume(')');
break;
default:
tail = unary_expression(head);
type = (struct typetree *) tail->expr.type;
break;
}
} else {
tail = unary_expression(head);
type = (struct typetree *) tail->expr.type;
}
if (is_function(type)) {
error("Cannot apply 'sizeof' to function type.");
}
if (!size_of(type)) {
error("Cannot apply 'sizeof' to incomplete type.");
}
block->expr = var_int(size_of(type));
break;
}
case INCREMENT:
consume(INCREMENT);
block = unary_expression(block);
value = block->expr;
block->expr = eval_expr(block, IR_OP_ADD, value, var_int(1));
block->expr = eval_assign(block, value, block->expr);
break;
case DECREMENT:
consume(DECREMENT);
block = unary_expression(block);
value = block->expr;
block->expr = eval_expr(block, IR_OP_SUB, value, var_int(1));
block->expr = eval_assign(block, value, block->expr);
break;
default:
block = postfix_expression(block);
break;
}
return block;
}
static void
eval_expr(m1_expression *e) {
if (e == NULL)
return;
switch (e->type) {
case EXPR_NUMBER:
eval_number(e->expr.l->value.fval);
break;
case EXPR_INT:
eval_int(e->expr.l->value.ival);
break;
case EXPR_BINARY:
eval_binary(e->expr.b);
break;
case EXPR_UNARY:
eval_unary(e->expr.u);
break;
case EXPR_FUNCALL:
eval_funcall(e->expr.f);
break;
case EXPR_ASSIGN:
eval_assign(e->expr.a);
break;
case EXPR_IF:
eval_if(e->expr.i);
break;
case EXPR_WHILE:
eval_while(e->expr.w);
break;
case EXPR_DOWHILE:
eval_dowhile(e->expr.w);
break;
case EXPR_FOR:
eval_for(e->expr.o);
break;
case EXPR_RETURN:
eval_return(e->expr.e);
break;
case EXPR_NULL:
eval_null();
break;
case EXPR_DEREF:
eval_deref(e->expr.t);
break;
case EXPR_ADDRESS:
eval_address(e->expr.t);
break;
case EXPR_OBJECT:
eval_obj(e->expr.t);
break;
case EXPR_BREAK:
eval_break();
break;
case EXPR_CONTINUE:
eval_continue();
break;
case EXPR_CONSTDECL:
case EXPR_VARDECL:
break;
default:
fprintf(stderr, "unknown expr type");
exit(EXIT_FAILURE);
}
}
