glslang: Only export public interface for SOs

CMakeLists.txt

@@ -205,6 +205,21 @@ if(BUILD_EXTERNAL AND IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/External)
 	add_subdirectory(External)
 endif()
 
+# glslang_only_export_explicit_symbols() makes the symbol visibility hidden by
+# default for <target> when building shared libraries, and sets the
+# GLSLANG_IS_SHARED_LIBRARY define, and GLSLANG_EXPORTING to 1 when specifically
+# building <target>.
+function(glslang_only_export_explicit_symbols target)
+    target_compile_definitions(${target} PUBLIC "GLSLANG_IS_SHARED_LIBRARY=1")
+    if(BUILD_SHARED_LIBS)
+        if(WIN32)
+            target_compile_definitions(${target} PRIVATE "GLSLANG_EXPORTING=1")
+        else()
+            target_compile_options(${target} PRIVATE "-fvisibility=hidden")
+        endif()
+    endif()
+endfunction()
+
 if(NOT TARGET SPIRV-Tools-opt)
     set(ENABLE_OPT OFF)
 endif()

StandAlone/StandAlone.cpp

@@ -63,7 +63,7 @@
 #include "../glslang/OSDependent/osinclude.h"
 
 extern "C" {
-    SH_IMPORT_EXPORT void ShOutputHtml();
+    GLSLANG_EXPORT void ShOutputHtml();
 }
 
 // Command-line options

glslang/CMakeLists.txt

@@ -132,6 +132,8 @@ target_include_directories(glslang PUBLIC
     $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/..>
     $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
 
+glslang_only_export_explicit_symbols(glslang)
+
 if(WIN32 AND BUILD_SHARED_LIBS)
     set_target_properties(glslang PROPERTIES PREFIX "")
 endif()