feat(backend/riscv32): 实现基础的编译器功能

- 完成 RV32IMA 指令集的代码生成
- 添加整数运算、分支、调用等基本指令支持
- 实现从 IR 到机器码的转换
- 添加简单的测试用例和测试框架

ccompiler/frontend/lexer/lexer.c

@@ -163,13 +163,14 @@ static void parse_char_literal(lexer_t* lexer, tok_t* token) {
     if (*peek == '\\') {
         peek++;
         val = got_slash(peek);
+        peek++;
     } else {
-        val = *peek;
+        val = *peek++;
     }
 
-    if (*peek != '\'') error("Unclosed character literal");
+    if (*peek++ != '\'') error("Unclosed character literal");
     token->val.ch = val;
-    lexer->cur_ptr = peek + 1;
+    lexer->cur_ptr = peek;
     token->val.have = 1;
     token->type = TOKEN_CHAR_LITERAL;
 }

ccompiler/frontend/lexer/tests/test.c

@@ -117,29 +117,23 @@ void test_literals() {
         // test_lexer_string("4294967295", TOKEN_INT_LITERAL); // UINT_MAX
     }
 
-    // TEST_CASE("Character literals"); {
-    //     test_lexer_string("'a'", TOKEN_CHAR_LITERAL);
-    //     test_lexer_string("'\\n'", TOKEN_CHAR_LITERAL);
-    //     test_lexer_string("'\\t'", TOKEN_CHAR_LITERAL);
-    //     test_lexer_string("'\\\\'", TOKEN_CHAR_LITERAL);
-    //     test_lexer_string("'\\0'", TOKEN_CHAR_LITERAL);
-    // }
+    TEST_CASE("Character literals"); {
+        test_lexer_string("'a'", TOKEN_CHAR_LITERAL);
+        test_lexer_string("'\\n'", TOKEN_CHAR_LITERAL);
+        test_lexer_string("'\\t'", TOKEN_CHAR_LITERAL);
+        test_lexer_string("'\\\\'", TOKEN_CHAR_LITERAL);
+        test_lexer_string("'\\0'", TOKEN_CHAR_LITERAL);
+    }
 
     TEST_CASE("String literals"); {
         test_lexer_string("\"hello\"", TOKEN_STRING_LITERAL);
         test_lexer_string("\"multi-line\\nstring\"", TOKEN_STRING_LITERAL);
         test_lexer_string("\"escape\\\"quote\"", TOKEN_STRING_LITERAL);
     }
-
-    // TEST_CASE("Integer literals");
-    // test_lexer_string("123", TOKEN_INT_LITERAL);
-    // test_lexer_string("0x1F", TOKEN_INT_LITERAL);
     
     // TEST_CASE("Floating literals");
     // test_lexer_string("3.14e-5", TOKEN_FLOAT_LITERAL);
     
-    // TEST_CASE("Character literals");
-    // test_lexer_string("'\\n'", TOKEN_CHAR_LITERAL);
 }
 
 // 边界测试

ccompiler/frontend/lexer/token.c

@@ -30,14 +30,13 @@ void init_tokbuf(tok_buf_t *tokbuf, void *stream, get_tokbuf_func gettok) {
     tokbuf->cap = 0;
 }
 
-tok_t *peek_tok(tok_buf_t *tokbuf)
-{
+tok_t *peek_tok(tok_buf_t *tokbuf) {
     int idx = tokbuf->peek;
-    idx = ROUND_IDX(idx + 1);
+    tokbuf->peek = ROUND_IDX(idx + 1);
     if (tokbuf->size >= tokbuf->cap) {
         error("peek too deep, outof array size");
     }
-    if (tokbuf->peek == tokbuf->end) {
+    if (idx == tokbuf->end) {
         if (tokbuf->size == tokbuf->cap) {
             error("peek_tok buffer overflow");
         }
@@ -46,10 +45,9 @@ tok_t *peek_tok(tok_buf_t *tokbuf)
         }
         tokbuf->gettok(tokbuf->stream, &(tokbuf->buf[idx]));
         tokbuf->size++;
-        tokbuf->end = idx;
+        tokbuf->end = tokbuf->peek;
     }
-    
-    tokbuf->peek = idx;
+
     return &(tokbuf->buf[idx]);
 }
 

ccompiler/frontend/parser/ast/ast.h

@@ -173,6 +173,8 @@ typedef struct ASTNode* (*parse_func_t) (parser_t*);
 
 void parse_prog(parser_t* parser);
 ast_node_t* parse_decl(parser_t* parser);
+ast_node_t* parse_decl_val(parser_t* parser);
+
 ast_node_t* parse_block(parser_t* parser);
 ast_node_t* parse_stmt(parser_t* parser);
 ast_node_t* parse_expr(parser_t* parser);

ccompiler/frontend/parser/ast/func.c

@@ -8,6 +8,7 @@
 
 // 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) {
+    flush_peek_tok(cache);
     tok_type_t ttype;
     ast_node_t *params = new_ast_node();
     node->decl_func.params = params;

ccompiler/frontend/parser/ast/stmt.c

@@ -89,8 +89,12 @@ ast_node_t* parse_stmt(parser_t* parser) {
 
         // init expr or init decl_var
         // TODO need add this feature
-        node->for_stmt.init = parse_expr(parser);
-        expect_pop_tok(tokbuf, TOKEN_SEMICOLON);
+        if (peek_decl(tokbuf)) {
+            node->for_stmt.init = parse_decl_val(parser);
+        } else {
+            node->for_stmt.init = parse_expr(parser);
+            expect_pop_tok(tokbuf, TOKEN_SEMICOLON);
+        }
 
         // cond expr or null
         ttype = peek_tok_type(tokbuf);