Merge pull request #23292 from CSBVision:patch-4

Add ENABLE_DELAYLOAD option

CMakeLists.txt

@@ -511,6 +511,7 @@ OCV_OPTION(INSTALL_TESTS            "Install accuracy and performance test binar
 # ===================================================
 OCV_OPTION(ENABLE_CCACHE              "Use ccache"                                               (UNIX AND (CMAKE_GENERATOR MATCHES "Makefile" OR CMAKE_GENERATOR MATCHES "Ninja" OR CMAKE_GENERATOR MATCHES "Xcode")) )
 OCV_OPTION(ENABLE_PRECOMPILED_HEADERS "Use precompiled headers"                                  MSVC IF (MSVC OR (NOT IOS AND NOT CMAKE_CROSSCOMPILING) ) )
+OCV_OPTION(ENABLE_DELAYLOAD           "Enable delayed loading of OpenCV DLLs"                    OFF VISIBLE_IF MSVC AND BUILD_SHARED_LIBS)
 OCV_OPTION(ENABLE_SOLUTION_FOLDERS    "Solution folder in Visual Studio or in other IDEs"        (MSVC_IDE OR CMAKE_GENERATOR MATCHES Xcode) )
 OCV_OPTION(ENABLE_PROFILING           "Enable profiling in the GCC compiler (Add flags: -g -pg)" OFF  IF CV_GCC )
 OCV_OPTION(ENABLE_COVERAGE            "Enable coverage collection with  GCov"                    OFF  IF CV_GCC )

cmake/OpenCVModule.cmake

@@ -368,6 +368,29 @@ macro(ocv_glob_modules main_root)
   # resolve dependencies
   __ocv_resolve_dependencies()
 
+  # optionally configure delay load
+  if(MSVC AND BUILD_SHARED_LIBS AND ENABLE_DELAYLOAD AND NOT BUILD_opencv_world)
+    if(${CMAKE_SHARED_LINKER_FLAGS} MATCHES "delayimp.lib")
+      set(DELAYFLAGS "")
+    else()
+      set(DELAYFLAGS "delayimp.lib")
+    endif()
+
+    foreach(mod ${OPENCV_MODULES_BUILD})
+      if(NOT ${mod} STREQUAL "opencv_core" AND NOT ${mod} MATCHES "bindings_generator|python")
+        set(DELAYFLAGS "${DELAYFLAGS} /DELAYLOAD:${mod}${OPENCV_VERSION_MAJOR}${OPENCV_VERSION_MINOR}${OPENCV_VERSION_PATCH}.dll")
+      endif()
+    endforeach()
+
+    if(NOT ${CMAKE_SHARED_LINKER_FLAGS} MATCHES "/IGNORE:4199")
+      set(DELAYFLAGS "${DELAYFLAGS} /IGNORE:4199")
+    endif()
+
+    set(CMAKE_EXE_LINKER_FLAGS       "${CMAKE_EXE_LINKER_FLAGS} ${DELAYFLAGS}")
+    set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} ${DELAYFLAGS}")
+    set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${DELAYFLAGS}")
+  endif()
+
   # create modules
   set(OPENCV_INITIAL_PASS OFF)
   ocv_cmake_hook(PRE_MODULES_CREATE)