loader: Export core symbols only.

Author: rpavlik

src/loader/CMakeLists.txt

@@ -35,6 +35,11 @@ if(WIN32)
     set(openxr_loader_RESOURCE_FILE ${CMAKE_CURRENT_SOURCE_DIR}/loader.rc)
 endif()
 
+if(NOT MSVC)
+    set(CMAKE_C_VISIBILITY_PRESET hidden)
+    set(CMAKE_CXX_VISIBILITY_PRESET hidden)
+endif()
+
 # List of all files externally generated outside of the loader that the loader
 # needs to build with.
 SET(LOADER_EXTERNAL_GEN_FILES
@@ -188,6 +193,7 @@ if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_C_COMPILER_ID MATCHES "Clang")
     target_compile_options(openxr_loader
         PRIVATE -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wpointer-arith
         PRIVATE -fno-strict-aliasing -fno-builtin-memcmp "$<$<COMPILE_LANGUAGE:CXX>:-fno-rtti>"
+        -ffunction-sections -fdata-sections
     )
     # For GCC version 7.1 or greater, we need to disable the implicit fallthrough warning since
     # there's no consistent way to satisfy all compilers until they all accept the C++17 standard

src/loader/loader_platform.hpp

@@ -31,6 +31,8 @@
 #define LOADER_EXPORT __attribute__((visibility("default")))
 #elif defined(__SUNPRO_C) && (__SUNPRO_C >= 0x590)
 #define LOADER_EXPORT __attribute__((visibility("default")))
+#elif defined(_WIN32) && defined(XRAPI_DLL_EXPORT)
+#define LOADER_EXPORT __declspec(dllexport)
 #else
 #define LOADER_EXPORT
 #endif

src/scripts/loader_source_generator.py

@@ -126,6 +126,7 @@ def beginFile(self, genOpts):
             preamble += '#include "openxr/openxr_platform.h"\n\n'
             preamble += '#include "loader_interfaces.h"\n\n'
             preamble += '#include "loader_instance.hpp"\n\n'
+            preamble += '#include "loader_platform.hpp"\n\n'
 
         elif self.genOpts.filename == 'xr_generated_loader.cpp':
             preamble += '#include "xr_generated_loader.hpp"\n\n'
@@ -208,6 +209,11 @@ def outputLoaderManualFuncs(self):
                     # Use the Cdecl directly from the XML
                     func_proto = cur_cmd.cdecl
 
+                    # Export only core functions
+                    if self.isCoreExtensionName(cur_cmd.ext_name):
+                        func_proto = func_proto.replace(
+                            "XRAPI_ATTR", "LOADER_EXPORT XRAPI_ATTR")
+
                     # Output the standard API form of the command
                     manual_funcs += func_proto
                     manual_funcs += '\n'
@@ -487,8 +493,14 @@ def outputLoaderGeneratedFuncs(self):
 
                 if cur_cmd.protect_value:
                     generated_funcs += '#if %s\n' % cur_cmd.protect_string
+                decl = cur_cmd.cdecl.replace(";", " XRLOADER_ABI_TRY {\n")
+
+                # Export only core functions
+                if self.isCoreExtensionName(cur_cmd.ext_name):
+                    decl = decl.replace(
+                        "XRAPI_ATTR", "LOADER_EXPORT XRAPI_ATTR")
 
-                generated_funcs += cur_cmd.cdecl.replace(";", " XRLOADER_ABI_TRY {\n")
+                generated_funcs += decl
                 generated_funcs += tramp_variable_defines
 
                 # If this is not core, but an extension, check to make sure the extension is enabled.