[core] Use version script to hide symbols in libCling

We already use -fvisibility=hidden and -fvisibility-inlines-hidden
to generate symbols that are not exported from the shared object.
However, these two options don't apply for non-inline template
instantiations, which can still cause problems when a STL container
is instantiated with an LLVM type that may change size between LLVM
versions.

Fixes #19889

Author: hahnjo

core/metacling/src/CMakeLists.txt

@@ -225,6 +225,8 @@ if(APPLE)
   target_link_libraries(Cling PUBLIC -Wl,-w -Wl,-bind_at_load -Wl,-undefined,dynamic_lookup)
 elseif(NOT MSVC)
   target_link_libraries(Cling PUBLIC -Wl,--unresolved-symbols=ignore-in-object-files)
+  target_link_libraries(Cling PRIVATE -Wl,--version-script=${CMAKE_CURRENT_SOURCE_DIR}/libCling.script)
+  set_target_properties(Cling PROPERTIES LINK_DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/libCling.script)
 endif()
 
 if (CMAKE_SYSTEM_NAME MATCHES FreeBSD)

core/metacling/src/libCling.script

@@ -0,0 +1,13 @@
+{
+  global:
+    CreateInterpreter;
+    DestroyInterpreter;
+    TCling__*;
+    _Z26TCling__TEST_isInvalidDeclP11ClassInfo_t;
+    TROOT__*;
+    ROOT_rootcling_Driver;
+    _ZN5cling*;
+    cling_runtime_internal_throwIfInvalidPointer;
+  local:
+    *;
+};