[SYCL][ABI-Break] Hide getPlugin symbol

This function is not called anywhere from SYCL headers and therefore
there is no reason to have it exported.

It was made exported as part of ESIMD emulator plugin addition
(intel#2963), but that plugin was since
then deprecated and removed (intel#13295).

Author: AlexeySachkov

sycl/include/sycl/detail/pi.hpp

@@ -194,7 +194,7 @@ extern std::shared_ptr<plugin> GlobalPlugin;
 std::vector<PluginPtr> &initialize();
 
 // Get the plugin serving given backend.
-template <backend BE> __SYCL_EXPORT const PluginPtr &getPlugin();
+template <backend BE> const PluginPtr &getPlugin();
 
 // Utility Functions to get Function Name for a PI Api.
 template <PiApiKind PiApiOffset> struct PiFuncInfo {};

sycl/source/detail/pi.cpp

@@ -508,11 +508,10 @@ template <backend BE> const PluginPtr &getPlugin() {
                   "pi::getPlugin couldn't find plugin");
 }
 
-template __SYCL_EXPORT const PluginPtr &getPlugin<backend::opencl>();
-template __SYCL_EXPORT const PluginPtr &
-getPlugin<backend::ext_oneapi_level_zero>();
-template __SYCL_EXPORT const PluginPtr &getPlugin<backend::ext_oneapi_cuda>();
-template __SYCL_EXPORT const PluginPtr &getPlugin<backend::ext_oneapi_hip>();
+template const PluginPtr &getPlugin<backend::opencl>();
+template const PluginPtr &getPlugin<backend::ext_oneapi_level_zero>();
+template const PluginPtr &getPlugin<backend::ext_oneapi_cuda>();
+template const PluginPtr &getPlugin<backend::ext_oneapi_hip>();
 
 // Report error and no return (keeps compiler from printing warnings).
 // TODO: Probably change that to throw a catchable exception,

sycl/test/abi/sycl_symbols_linux.dump

@@ -3304,10 +3304,6 @@ _ZN4sycl3_V16detail28getValueFromDynamicParameterERNS0_3ext6oneapi12experimental
 _ZN4sycl3_V16detail2pi25contextSetExtendedDeleterERKNS0_7contextEPFvPvES6_
 _ZN4sycl3_V16detail2pi3dieEPKc
 _ZN4sycl3_V16detail2pi9assertionEbPKc
-_ZN4sycl3_V16detail2pi9getPluginILNS0_7backendE1EEERKSt10shared_ptrINS1_6pluginEEv
-_ZN4sycl3_V16detail2pi9getPluginILNS0_7backendE2EEERKSt10shared_ptrINS1_6pluginEEv
-_ZN4sycl3_V16detail2pi9getPluginILNS0_7backendE3EEERKSt10shared_ptrINS1_6pluginEEv
-_ZN4sycl3_V16detail2pi9getPluginILNS0_7backendE6EEERKSt10shared_ptrINS1_6pluginEEv
 _ZN4sycl3_V16detail30UnsampledImageAccessorBaseHost10getAccDataEv
 _ZN4sycl3_V16detail30UnsampledImageAccessorBaseHost6getPtrEv
 _ZN4sycl3_V16detail30UnsampledImageAccessorBaseHostC1ENS0_5rangeILi3EEENS0_6access4modeEPviiNS0_2idILi3EEENS0_18image_channel_typeENS0_19image_channel_orderERKNS0_13property_listE

sycl/test/abi/sycl_symbols_windows.dump

@@ -14,10 +14,6 @@
 ??$create_sub_devices@$0BAII@@device@_V1@sycl@@QEBA?AV?$vector@Vdevice@_V1@sycl@@V?$allocator@Vdevice@_V1@sycl@@@std@@@std@@W4partition_affinity_domain@info@12@@Z
 ??$create_sub_devices@$0BAIJ@@device@_V1@sycl@@QEBA?AV?$vector@Vdevice@_V1@sycl@@V?$allocator@Vdevice@_V1@sycl@@@std@@@std@@XZ
 ??$ext_oneapi_get_info@Umax_num_work_group_sync@kernel_queue_specific@info@experimental@oneapi@ext@_V1@sycl@@@kernel@_V1@sycl@@QEBA_KAEBVqueue@12@@Z
-??$getPlugin@$00@pi@detail@_V1@sycl@@YAAEBV?$shared_ptr@Vplugin@detail@_V1@sycl@@@std@@XZ
-??$getPlugin@$01@pi@detail@_V1@sycl@@YAAEBV?$shared_ptr@Vplugin@detail@_V1@sycl@@@std@@XZ
-??$getPlugin@$02@pi@detail@_V1@sycl@@YAAEBV?$shared_ptr@Vplugin@detail@_V1@sycl@@@std@@XZ
-??$getPlugin@$05@pi@detail@_V1@sycl@@YAAEBV?$shared_ptr@Vplugin@detail@_V1@sycl@@@std@@XZ
 ??$get_backend_info@Ubackend_version@device@info@_V1@sycl@@@context@_V1@sycl@@QEBA?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@XZ
 ??$get_backend_info@Ubackend_version@device@info@_V1@sycl@@@device@_V1@sycl@@QEBA?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@XZ
 ??$get_backend_info@Ubackend_version@device@info@_V1@sycl@@@event@_V1@sycl@@QEBA?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@XZ