feat(pproc): 实现预处理器条件编译和可变参数宏支持

- 添加了完整的条件编译功能，包括 #if、#elif、#else、#endif 指令 - 实现了数值常量表达式的解析和求值 - 支持嵌套条件编译和与其他指令混合使用 - 实现了可变参数宏定义和 __VA_ARGS__ 替换功能 - 改进了宏展开机制以正确处理可变参数宏 - 重构了预处理器指令处理逻辑，提高了代码可维护性 - 添加了相应的单元测试用例验证新功能
2026-02-21 15:59:31 +08:00
parent b705e5d0ad
commit 8007825800
7 changed files with 317 additions and 134 deletions
--- a/libs/pproc/src/pproc_if.c
+++ b/libs/pproc/src/pproc_if.c
@@ -0,0 +1,172 @@
+#include <scc_lexer_utils.h>
+#include <scc_pproc.h>
+
+cbool scc_pproc_parse_if_defined(scc_pproc_t *pp, scc_tok_type_t type,
+                                 const scc_lexer_tok_t *tok) {
+    int defined = 0;
+    if (tok) {
+        defined = (scc_pproc_macro_table_get(&pp->macro_table,
+                                             &(tok->lexeme)) != null);
+    }
+    switch (type) {
+    case SCC_PP_TOK_IFDEF:
+    case SCC_PP_TOK_IFNDEF: {
+        cbool condition = (type == SCC_PP_TOK_IFDEF) ? defined : !defined;
+
+        scc_pproc_if_t new_if;
+        new_if.found_true = condition;
+        new_if.seen_else = 0;
+        new_if.active = pp->enable ? condition : 0;
+        scc_vec_push(pp->if_stack, new_if);
+
+        pp->enable = new_if.active;
+        break;
+    }
+    case SCC_PP_TOK_ELIFDEF:
+    case SCC_PP_TOK_ELIFNDEF: {
+        if (scc_vec_size(pp->if_stack) == 0) {
+            LOG_ERROR("#elif without #if");
+            return false;
+        }
+        scc_pproc_if_t *top =
+            &scc_vec_at(pp->if_stack, scc_vec_size(pp->if_stack) - 1);
+        if (top->seen_else) {
+            LOG_ERROR("#elif after #else");
+            return false;
+        }
+
+        int condition = (type == SCC_PP_TOK_ELIFDEF) ? defined : !defined;
+
+        if (top->found_true) {
+            // 前面已有真分支，本 elif 不激活
+            top->active = 0;
+        } else {
+            if (condition) {
+                top->active = 1;
+                top->found_true = 1;
+            } else {
+                top->active = 0;
+            }
+        }
+
+        // seen_else 仍为 0
+        pp->enable = top->active;
+        break;
+    }
+    case SCC_PP_TOK_ELSE: {
+        if (scc_vec_size(pp->if_stack) == 0) {
+            LOG_ERROR("#else without #if");
+            return false;
+        }
+        scc_pproc_if_t *top =
+            &scc_vec_at(pp->if_stack, scc_vec_size(pp->if_stack) - 1);
+        if (top->seen_else) {
+            LOG_ERROR("multiple #else");
+            return false;
+        }
+
+        if (top->found_true) {
+            top->active = 0;
+        } else {
+            top->active = 1;
+            top->found_true = 1;
+        }
+
+        top->seen_else = 1;
+
+        pp->enable = top->active;
+        break;
+    }
+    case SCC_PP_TOK_ENDIF: {
+        if (scc_vec_size(pp->if_stack) == 0) {
+            LOG_ERROR("#endif without #if");
+        } else {
+            scc_vec_pop(pp->if_stack);
+        }
+        if (scc_vec_size(pp->if_stack) == 0) {
+            pp->enable = 1;
+        } else {
+            pp->enable =
+                scc_vec_at(pp->if_stack, scc_vec_size(pp->if_stack) - 1).active;
+        }
+        break;
+    }
+    default: {
+        LOG_FATAL("unexpected directive");
+    }
+    }
+    return true;
+}
+
+static cbool parse_constant_condition() { return false; }
+
+cbool scc_pproc_parse_if_condition(scc_pproc_t *pp, scc_tok_type_t type,
+                                   scc_lexer_tok_ring_t *tok_ring) {
+    // TODO
+    int ok;
+    scc_lexer_tok_t tok = {0};
+    ok = scc_lexer_next_non_blank(tok_ring, &tok);
+    if (ok == false) {
+        LOG_FATAL("unexpected EOF");
+    }
+    int condition = 0;
+    if (tok.type == SCC_TOK_INT_LITERAL) {
+        condition = scc_cstring_as_cstr(&tok.lexeme)[0] == '0' ? 0 : 1;
+    } else {
+        LOG_ERROR("expected integer constant");
+    }
+    scc_lexer_tok_drop(&tok);
+
+    ok = scc_lexer_next_non_blank(tok_ring, &tok);
+    if (ok == false) {
+        LOG_FATAL("unexpected EOF");
+    }
+    if (tok.type != SCC_TOK_ENDLINE) {
+        LOG_ERROR("expected endline");
+        scc_lexer_skip_until_newline(tok_ring);
+    } else {
+        scc_lexer_tok_drop(&tok);
+    }
+    scc_ring_free(*tok_ring);
+
+    // 根据指令类型更新条件编译栈
+    switch (type) {
+    case SCC_PP_TOK_IF: {
+        scc_pproc_if_t new_if;
+        new_if.found_true = condition;
+        new_if.seen_else = 0;
+        new_if.active = pp->enable ? condition : 0;
+        scc_vec_push(pp->if_stack, new_if);
+        pp->enable = new_if.active;
+        break;
+    }
+    case SCC_PP_TOK_ELIF: {
+        if (scc_vec_size(pp->if_stack) == 0) {
+            LOG_ERROR("#elif without #if");
+            return false;
+        }
+        scc_pproc_if_t *top =
+            &scc_vec_at(pp->if_stack, scc_vec_size(pp->if_stack) - 1);
+        if (top->seen_else) {
+            LOG_ERROR("#elif after #else");
+            return false;
+        }
+        if (top->found_true) {
+            top->active = 0;
+        } else {
+            if (condition) {
+                top->active = 1;
+                top->found_true = 1;
+            } else {
+                top->active = 0;
+            }
+        }
+        pp->enable = top->active;
+        break;
+    }
+    default:
+        LOG_FATAL("unexpected directive in parse_if_condition");
+    }
+    return true;
+    return true;
+}