Add dummy_calls to ensure query_stable and free_result not optimized …

…out (#171)

* Fix warnings

* Fix typo

* Run libchdb.so test on linux arm64

* Print all global symbols

* Debug libchdb on macOS

* Add dummy_calls to ensure query_stable and free_result not optimized out

.github/workflows/build_wheels.yml

@@ -232,11 +232,20 @@ jobs:
           python3 -m pip install pandas pyarrow
           bash -x ./chdb/test_smoke.sh
         continue-on-error: false
-      - name: Show libchdb
+      - name: Debug libchdb
         run: |
           ls -lh
           nm libchdb.so | grep query_stable || true
+          echo "Global Symbol in libchdb.so:"
           nm -g libchdb.so || true
+          echo "Global Symbol in libclickhouse-local-chdb.a:"
+          nm -g buildlib/programs/local/libclickhouse-local-chdb.a || true
+          echo "Global Symbol in libclickhouse-local-lib.a:"
+          nm -g buildlib/programs/local/libclickhouse-local-lib.a || true
+          echo "pychdb_cmd.sh:"
+          cat buildlib/pychdb_cmd.sh
+          echo "libchdb_cmd.sh:"
+          cat buildlib/libchdb_cmd.sh
       - name: Run libchdb stub in examples dir
         run: |
           bash -x ./examples/runStub.sh

programs/local/LocalServer.cpp

@@ -1097,9 +1097,31 @@ void free_result(local_result * result)
     result->_vec = nullptr;
 }
 
+/**
+ * The dummy_calls function is used to prevent certain functions from being optimized out by the compiler.
+ * It includes calls to 'query_stable' and 'free_result' within a condition that is always false. 
+ * This approach ensures these functions are recognized as used by the compiler, particularly under high 
+ * optimization levels like -O3, where unused functions might otherwise be discarded.
+ * 
+ * Without this the Github runner macOS 12 builder will fail to find query_stable and free_result.
+ * It is strange because the same code works fine on my own macOS 12 x86_64 and arm64 machines.
+ *
+ * To prevent further clang or ClickHouse compile flags from affecting this, the function is defined here
+ * and called from mainEntryClickHouseLocal.
+ */
+bool always_false = false;
+void dummy_calls()
+{
+    if (always_false)
+    {
+        struct local_result * result = query_stable(0, nullptr);
+        free_result(result);
+    }
+}
 
 int mainEntryClickHouseLocal(int argc, char ** argv)
 {
+    dummy_calls();
     auto result = pyEntryClickHouseLocal(argc, argv);
     if (result)
     {

programs/local/chdb.h

@@ -9,7 +9,8 @@ extern "C" {
 #    include <stdint.h>
 #endif
 
-struct __attribute__((visibility("default"))) local_result
+#define CHDB_EXPORT __attribute__((visibility("default")))
+struct CHDB_EXPORT local_result
 {
     char * buf;
     size_t len;
@@ -19,8 +20,8 @@ struct __attribute__((visibility("default"))) local_result
     uint64_t bytes_read;
 };
 
-__attribute__((visibility("default"))) struct local_result * query_stable(int argc, char ** argv);
-__attribute__((visibility("default"))) void free_result(struct local_result * result);
+CHDB_EXPORT struct local_result * query_stable(int argc, char ** argv);
+CHDB_EXPORT void free_result(struct local_result * result);
 
 #ifdef __cplusplus
 }