parse.c

#include "smc.h"

// program = function*
Node *program(void){
	Node head = {};
	Node *cur = &head;
	while (!at_eof()){
		cur->func_next = function();
		cur = cur->func_next;
	}
	cur->func_next = NULL;
	return head.func_next;
}
// indent"(" args? ")" "{" stmt* "}"
// args =  "(" "int" indent ( "," "int" indent )* ")"
Node *function(){
	expect("int");
	Node *node = new_node_func();
	node->lvar = calloc(1, sizeof(LVar));
	locals = node->lvar;
	expect("(");
	if(consume(")")){
	}else{
		while(1){
			expect("int");
			LVar *lvar = calloc(1, sizeof(LVar));
			lvar->type = calloc(1, sizeof(Type));
			Type *temp = lvar->type;
			while (consume("*")){
				temp->ty = PTR;
				temp->ptr_to = calloc(1, sizeof(Type));
				temp = temp->ptr_to;
				fprintf(stderr, "*がconsumeされました\n");
			}
			temp->ty = INT;
			lvar->prev = locals;
			locals->next = lvar;
			lvar->next = NULL;
			lvar->arg_flag = 1;
			lvar->name = token->str;
			lvar->len = token->len;
			lvar->offset = locals->offset + 8;
			locals = lvar;
			token = token->next;
			if(consume(")")){
				break;
			}else{
				expect(",");
			}
		}
	}
	expect("{");
	Node head = {};
	Node *cur = &head;
	while (1){
		cur->next = stmt();
		cur = cur->next;
		if(consume("}")){
			cur = NULL;
			node->next = head.next;
			break;
		}
	}
	return node;
}
// stmt = expr ";" | "return" expr ";" | "{" stmt* "}" | "if" "(" expr ")" stmt ("else" stmt)?
//       | "while" "(" expr ")" stmt | "for" "(" expr ";" expr ";" expr ")" stmt
Node *stmt(void){
	Node *node;
	if(consume("return")){
		node = new_node(ND_RETURN, expr(), NULL);
		expect(";");
	}else if(consume("{")){
		node = new_node(ND_BLOCK, NULL, NULL);
		Node head = {};
		Node *cur = &head;
		while (1){
			if (consume("}")){
				cur = NULL;
				node->block = head.block_next;
				break;
			}
			cur->block_next = stmt();
			cur = cur->block_next;
		}
	}else if(consume("if")){
		node = new_node(ND_IF, NULL, NULL);
		expect("(");
		node->cond = expr();
		expect(")");
		node->then = stmt();
		if(consume("else")){
			node->els = stmt();
		}
	}else if(consume("while")){
		node = new_node(ND_WHILE, NULL, NULL);
		expect("(");
		node->cond = expr();
		expect(")");
		node->then = stmt();
	}else if(consume("for")){
		node = new_node(ND_FOR, NULL, NULL);
		expect("(");
		node->init = expr();
		expect(";");
		node->cond = expr();
		expect(";");
		node->inc = expr();
		expect(")");
		node->then = stmt();
	}else{
		node = expr();
		expect(";");
	}
	return node;
}
// expr = assign | int ident
Node *expr(void){
	Node *node;
	if(consume("int")){
		node = new_node_identdef();
	}else{
		node = assign();
	}
	return node;
}
// assign = equality ("=" assign)?
Node *assign(void){
	Node *node = equality();
	if (consume("=")){
		node = new_node(ND_ASSIGN, node, assign());
	}
	return node;
}
// equality = relational ("==" relational | "!=" relational)*
Node *equality(void){
	Node *node = relational();
	while (1){
		if(consume("==")){
			node = new_node(ND_EQ, node, relational());
		}else if (consume("!=")){
			node = new_node(ND_NE, node, relational());
		}else{
			return node;
		}
	}
}
// relational = add ("<" add | "<=" add | ">" add | ">=" add)*
Node *relational(void){
	Node *node = add();
	while (1){
		if (consume("<")){
			node = new_node(ND_LT, node, add());
		}else if (consume("<=")){
			node = new_node(ND_LE, node, add());
		}else if(consume(">")){
			node = new_node(ND_LT, add(), node);
		}else if(consume(">=")){
			node = new_node(ND_LE, add(), node);
		}else{
			return node;
		}
	}
}
// add = mul ("+" mul | "-" mul)*
Node *add(void){
	Node *node = mul();
	while (1){
		if (consume("+")){
			node = new_node(ND_ADD, node, mul());
		}else if (consume("-")){
			node = new_node(ND_SUB, node, mul());
		}else{
			return node;
		}
	}
}
// mul = unary ("*" unary | "/" unary)*
Node *mul(void){
	Node *node = unary();
	while(1){
		if (consume("*")){
			node = new_node(ND_MUL, node, unary());
		}else if (consume("/")){
			node = new_node(ND_DIV, node, unary());
		}else{
			return node;
		}
	}
}
// unary = ("+" | "-" | "*" | "&")* unary | primary
Node *unary(void){
	if (consume("+")){
		return unary();
	}else if (consume("-")){
		return new_node(ND_SUB, new_node_num(0), unary());
	}else if(consume("*")){
		return new_node(ND_DEREF, unary(), NULL);
	}else if(consume("&")){
		return new_node(ND_ADDR, unary(), NULL);
	}
	return primary();
}
// primary = num | ident args? | "(" expr ")"
// args =  "(" expr ( "," expr )* ")"
Node *primary(void){
	Node *node;
	if (consume("(")){
		node = expr();
		expect(")");
		return node;
	}else if(token->kind == TK_IDENT){
		if(token->next->str[0] == '('){
			return func_call();
		}
		return new_node_ident();
	}
	return new_node_num(expect_number());
}

Node *func_call(void){
	Node *node = new_node(ND_FUNCCALL, NULL, NULL);
	node->funcname = calloc((token->len + 1), sizeof(char));
	strncpy(node->funcname, token->str, token->len);
	token = token->next;
	expect("(");
	if(consume(")")){
		node->args = NULL;
		return node;
	}
	Node head = {};
	Node *cur = &head;
	while(1){
		cur->args_next = expr();
		cur = cur->args_next;
		if(consume(")")){
			cur->args_next = NULL;
			node->args = head.args_next;
			break;
		}else{
			expect(",");
		}
	}
	return node;
}

// エラーとその場所を表示
void error_at(char *loc, char *fmt, ...){
	va_list ap;
	va_start(ap, fmt);
	int pos = loc - user_input;
	fprintf(stderr, "%s\n", user_input);
	fprintf(stderr, "%*s", pos, " ");
	fprintf(stderr, "^ ");
	vfprintf(stderr, fmt, ap);
	fprintf(stderr, "\n");
	va_end(ap);
	exit(1);
}

// 演算子の場合tokenを進める
bool consume(char *op){
	if ((token->kind != TK_RESERVED && token->kind != TK_CONTROL) || strlen(op) != token->len || memcmp(token->str, op, token->len) != 0){
		return false;
	}
	token = token->next;
	return true;
}

// やってること自体はconsumeと同じ,TFを返すかどうかが違い
void expect(char *op){
	if ((token->kind != TK_RESERVED && token->kind != TK_CONTROL) || strlen(op) != token->len || memcmp(token->str, op, token->len) != 0)
		error_at(token->str,"'%s'ではありません", op);
	token = token->next;
}

// 数字が来ると想定される場所で(演算子の後)、数字を返す
int expect_number(void){
	if (token->kind != TK_NUM)
		error_at(token->str, "数ではありません");
	int val = token->val;
	token = token->next;
	return val;
}

// 最後のtokenかを判別する
bool at_eof(void){
	return token->kind == TK_EOF;
}

LVar *find_lvar(Token *tok){
	for (LVar *var = locals; var; var = var->prev)
		if (var->len == tok->len && !memcmp(tok->str, var->name, var->len))
			return var;
	return NULL;
}