stage2 提供词法分析器通过与stage1的差异测试 stage1提供数组到切片的隐式转换

nob.c

@@ -133,12 +133,33 @@ static bool collect_headers(void) {
     return true;
 }
 
+// stage2 的所有 .spl：作为 splc1.sir 的依赖（不解析 @import，保守全量重建）。
+static Nob_Files g_spl2 = {0};
+
+static bool collect_spl2_entry(Nob_Walk_Entry entry) {
+    if (entry.type != NOB_FILE_REGULAR)
+        return true;
+    const char *dot = strrchr(entry.path, '.');
+    if (!dot || strcmp(dot, ".spl") != 0)
+        return true;
+    da_append(&g_spl2, nob_temp_strdup(entry.path));
+    return true;
+}
+
+static bool collect_spl2(void) {
+    if (g_spl2.count > 0)
+        return true;
+    return nob_walk_dir("stage2", collect_spl2_entry);
+}
+
 static bool prepare_build(void) {
     if (!nob_mkdir_if_not_exists(BUILD_FOLDER))
         return false;
     if (!sync_cflags_stamp())
         return false;
-    return collect_headers();
+    if (!collect_headers())
+        return false;
+    return collect_spl2();
 }
 
 static bool build_object(const char *src) {
@@ -320,6 +341,105 @@ static bool test_once_with_dump(const char *fname, void *user_data) {
     return nob_cmd_run(&cmd);
 }
 
+// 用 splc0 编译 stage2/splc1.spl -> build/splc1.sir（依赖 stage2 全部 .spl）。
+static bool build_splc1(void) {
+    if (!build_target("splc0"))
+        return false;
+
+    const char *src = "stage2/splc1.spl";
+    const char *sir = BUILD_FOLDER "splc1.sir";
+
+    size_t ninputs = g_spl2.count + 2;
+    const char **inputs = (const char **)nob_temp_alloc(sizeof(const char *) * ninputs);
+    inputs[0] = src;
+    for (size_t i = 0; i < g_spl2.count; ++i)
+        inputs[i + 1] = g_spl2.items[i];
+    inputs[ninputs - 1] = CFLAGS_STAMP;
+
+    int needs = nob_needs_rebuild(sir, inputs, ninputs);
+    if (needs < 0)
+        return false;
+    if (needs == 0)
+        return true;
+
+    Nob_Cmd cmd = {0};
+    nob_cmd_append(&cmd, exe_path("splc0"), src, sir);
+    return nob_cmd_run(&cmd);
+}
+
+static bool run_capture(Nob_Cmd *cmd, Nob_Cmd_Result *result) {
+    Nob_String_Builder rendered = {0};
+    nob_cmd_render(*cmd, &rendered);
+    Nob_String_View sv = nob_sb_to_sv(rendered);
+    bool ok = nob_cmd_capture_popen(nob_temp_sv_to_cstr(sv), result);
+    nob_sb_free(rendered);
+    return ok;
+}
+
+// diff 测试：对同一文件跑 `splc0 --dump <mode>` 与 `spl_cli splc1.sir --dump <mode>`，
+// 逐字节比较 stdout。
+static bool test_once_diff(const char *fname, void *user_data) {
+    const char *mode = (const char *)user_data;
+    if (!mode) {
+        nob_log(NOB_ERROR, "diff test requires a mode: lex|ast|sema|ir|vm");
+        return false;
+    }
+    if (!build_target("splc0"))
+        return false;
+    if (!build_target("spl_cli"))
+        return false;
+    if (!build_splc1())
+        return false;
+
+    Nob_Cmd c_cmd = {0};
+    nob_cmd_append(&c_cmd, exe_path("splc0"), "--dump", (char *)mode, (char *)fname,
+                   BUILD_FOLDER "diff_c.sir");
+    Nob_Cmd_Result c_res = {0};
+    if (!run_capture(&c_cmd, &c_res)) {
+        nob_cmd_result_free(c_res);
+        return false;
+    }
+
+    Nob_Cmd s_cmd = {0};
+    nob_cmd_append(&s_cmd, exe_path("spl_cli"), BUILD_FOLDER "splc1.sir", "--dump",
+                   (char *)mode, (char *)fname);
+    Nob_Cmd_Result s_res = {0};
+    if (!run_capture(&s_cmd, &s_res)) {
+        nob_cmd_result_free(c_res);
+        nob_cmd_result_free(s_res);
+        return false;
+    }
+
+    Nob_String_View c_out = nob_sb_to_sv(c_res.out);
+    Nob_String_View s_out = nob_sb_to_sv(s_res.out);
+    bool same = nob_sv_eq(c_out, s_out);
+    if (!same) {
+        nob_log(NOB_ERROR, "diff mismatch: %s (c=%zu bytes, spl=%zu bytes)", fname,
+                c_out.count, s_out.count);
+        // 打印首个不相同行（按行比较）。
+        Nob_String_View ca = c_out;
+        Nob_String_View sa = s_out;
+        size_t lineno = 1;
+        while (ca.count > 0 || sa.count > 0) {
+            Nob_String_View cl = nob_sv_chop_by_delim(&ca, '\n');
+            Nob_String_View sl = nob_sv_chop_by_delim(&sa, '\n');
+            if (!nob_sv_eq(cl, sl)) {
+                nob_log(NOB_ERROR, "  line %zu:", lineno);
+                nob_log(NOB_ERROR, "    c  : %.*s", (int)cl.count, cl.data);
+                nob_log(NOB_ERROR, "    spl: %.*s", (int)sl.count, sl.data);
+                break;
+            }
+            lineno++;
+        }
+        nob_log(NOB_ERROR, "--- c stderr/stdout merged above; exit=%d vs spl exit=%d ---",
+                c_res.exit_code, s_res.exit_code);
+    }
+
+    nob_cmd_result_free(c_res);
+    nob_cmd_result_free(s_res);
+    return same;
+}
+
 static bool is_stage_name(const char *s) {
     return strcmp(s, "stage1") == 0 || strcmp(s, "stage2") == 0 || strcmp(s, "diff") == 0;
 }
@@ -481,6 +601,15 @@ int main(int argc, char **argv) {
             }
         }
 
+        // diff 需要显式 mode，且使用专门的双编译器比较函数。
+        if (strcmp(stage, "diff") == 0) {
+            if (!mode_name) {
+                nob_log(NOB_ERROR, "diff requires a mode: lex|ast|sema|ir|vm");
+                return 1;
+            }
+            tfn = test_once_diff;
+        }
+
         // 3. 剩下的都当 pattern
         Nob_Files files = {0};
         while (argc > 0) {