smcc/ccompiler/frontend/parser/ast/func.c

#include "../parser.h"
#include "../symtab/symtab.h"
#include "ast.h"

#ifndef FUNC_PARAM_CACHE_SIZE
#define FUNC_PARAM_CACHE_SIZE 32  // 合理初始值，可覆盖99%常见情况
#endif

// TODO 语义分析压入符号表
static void parse_params(parser_t* parser, tok_buf_t* cache, ast_node_t* node) {
    tok_type_t ttype;
    ast_node_t *params = new_ast_node();
    node->decl_func.params = params;
    vector_init(params->params.params);

    int depth = 1;
    while (depth) {
        ttype = peek_tok_type(cache);
        switch (ttype) {
        case TOKEN_COMMA:
            break;
        case TOKEN_ELLIPSIS:
            ttype = peek_tok_type(cache);
            if (ttype != TOKEN_R_PAREN) {
                error("... must be a last parameter list (expect ')')");
            }
            // TODO
            error("not implement");
            break;
        case TOKEN_IDENT:
            // TODO 静态数组
            flush_peek_tok(cache);
            ast_node_t* id_node = new_ast_ident_node(peek_tok(cache));
            ast_node_t* node = new_ast_node();
            node->type = NT_DECL_VAR;
            node->decl_val.name = id_node;
            // TODO typing sys
            node->decl_val.type = NULL;
            node->decl_val.expr_stmt = NULL;
            node->decl_val.data = NULL;
            vector_push(params->params.params, node);
            symtab_add_symbol(parser->symtab, id_node->syms.tok.val.str, node, 0);
            break;
        case TOKEN_L_PAREN: {
            depth++;
            break;
        }
        case TOKEN_R_PAREN: {
            depth--;
            break;
        }
        default:
            break;
            // TODO 使用cache的类型解析
            // parse_type(parser);
            // TODO type parse
            // ttype = peekcachetype(cache);
            // ttype = peekcachetype(cache);
            // if (ttype != TOKEN_IDENT) {
            //     node->node_type = NT_DECL_FUNC;
            //     flush_peek_tok(tokbuf);
            //     continue;
            // }
            // error("function expected ')' or ','\n");
        }
        pop_tok(cache);
    }
}

ast_type_t check_is_func_decl(tok_buf_t* tokbuf, tok_buf_t* cache) {
    expect_pop_tok(tokbuf, TOKEN_L_PAREN);
    int depth = 1;
    
    while (depth) {
        tok_t* tok = peek_tok(tokbuf);
        pop_tok(tokbuf);
        if (cache->size >= cache->cap - 1) {
            error("function parameter list too long");
        }
        cache->buf[cache->size++] = *tok;
        switch (tok->type) {
        case TOKEN_L_PAREN:
            depth++;
            break;
        case TOKEN_R_PAREN:
            depth--;
            break;
        default:
            break;
        }
    }
    cache->end = cache->size;

    switch (peek_tok_type(tokbuf)) {
        case TOKEN_SEMICOLON:
            pop_tok(tokbuf);
            return NT_DECL_FUNC;
        case TOKEN_L_BRACE:
            return NT_FUNC;
            break;
        default:
            error("function define or decl need '{' or ';' but you don't got");
    }
}

static ast_node_t* new_ast_node_funcdecl(ast_node_t* ret, ast_node_t* name) {
    ast_node_t* node = new_ast_node();
    node->type = NT_DECL_FUNC;
    node->decl_func.ret = ret;
    node->decl_func.name = name;
    node->decl_func.def = NULL;
    return node;
}

void parse_func(parser_t* parser) {
    tok_buf_t* tokbuf = &(parser->tokbuf);
    flush_peek_tok(tokbuf);
    ast_node_t* ret_node = parse_type(parser);
    ast_node_t* name_node = expect_pop_ident(tokbuf);
    const char* func_name = name_node->syms.tok.val.str;
    ast_node_t* decl = new_ast_node_funcdecl(ret_node, name_node);

    tok_buf_t cache;
    init_tokbuf(&cache, NULL, NULL);
    cache.cap = FUNC_PARAM_CACHE_SIZE;
    tok_t buf[FUNC_PARAM_CACHE_SIZE];
    cache.buf = buf;
    
    ast_type_t type = check_is_func_decl(&(parser->tokbuf), &cache);

    ast_node_t* prev = symtab_add_symbol(parser->symtab, func_name, decl, 1);
    if (prev != NULL) {
        if (prev->type != NT_DECL_FUNC) {
            error("the symbol duplicate old is %d, new is func", prev->type);
        }
        // TODO check redeclare func is match
        if (type == NT_FUNC) {
            // TODO Free decl;
            free(decl);
            decl = prev;
            goto FUNC;
        }
        return;
    }
    vector_push(parser->root->root.children, decl);
    if (type == NT_DECL_FUNC) {
        return;
    }

FUNC:
    // 该data临时用于判断是否重复定义
    if (decl->decl_func.def != NULL) {
        error("redefinition of function %s", func_name);
    }

    ast_node_t* node = new_ast_node();
    node->type = NT_FUNC;
    node->func.decl = decl;
    node->func.data = NULL;

    decl->decl_func.def = node;
    symtab_enter_scope(parser->symtab);
    parse_params(parser, &cache, decl);
    node->func.body = parse_block(parser);
    symtab_leave_scope(parser->symtab);

    vector_push(parser->root->root.children, node);
}