CMake: Fix generated prl and pri files for MSVC

In MSVC static build, if we build Qt with 3rdparty library (e.g. zstd),
cmake will add"zstd" (without "-l" prefix) to Qt6Core.prl. Then we
use this Qt to build a qmake project, compilation will fail due to
missing zstd.obj. Without "-l" prefix, qmake will treat "zstd" as an
object file instead of a library.

Library names in qt_module.pri and qt_lib_*_private.pri are also
missing "-l" prefix.

This is because on most compilers, CMAKE_LINK_LIBRARY_FLAG equals
"-l". But on MSVC, it is an empty string. So we should pass
"-DLINK_LIBRARY_FLAG=-l" for MSVC.

Also add "-L/path/to/library" if the library path is not in default
linker search directories. This will write un-relocatable paths to prl
files only when using 3rdparty libraries to build Qt statically. Usually
it's not a problem.

In addition, CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES is also empty on
MSVC. So The third argument of "$<FILTER>" is empty, it is an invalid
generator expression. This means no include dir will be written to
qt_module.pri and qt_lib_*_private.pri on MSVC. So only use "$<FILTER>"
when CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES is not empty.

Change-Id: Ib66f95dc09cf920363a4b9338fb97747dd2f8ab7
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
(cherry picked from commit 2c49f85380d7ad79d9473e0f42e7afaa36d31af9)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

5 files changed, 33 insertions, 5 deletions

diff --git a/cmake/QtFinishPrlFile.cmake b/cmake/QtFinishPrlFile.cmake
index 7de3bd48f3..3e76f0decf 100644
--- a/cmake/QtFinishPrlFile.cmake
+++ b/cmake/QtFinishPrlFile.cmake
@@ -19,6 +19,7 @@
 # LIBRARY_SUFFIXES: list of known library extensions, e.g. .so;.a on Linux
 # LIBRARY_PREFIXES: list of known library prefies, e.g. the "lib" in "libz" on on Linux
 # LINK_LIBRARY_FLAG: flag used to link a shared library to an executable, e.g. -l on UNIX
+# IMPLICIT_LINK_DIRECTORIES: list of implicit linker search paths
 
 include("${CMAKE_CURRENT_LIST_DIR}/QtGenerateLibHelpers.cmake")
 
diff --git a/cmake/QtGenerateLibHelpers.cmake b/cmake/QtGenerateLibHelpers.cmake
index dedcdc7950..913b0ed90a 100644
--- a/cmake/QtGenerateLibHelpers.cmake
+++ b/cmake/QtGenerateLibHelpers.cmake
@@ -64,6 +64,12 @@ function(qt_transform_absolute_library_paths_to_link_flags out_var library_path_
     foreach(library_path ${library_path_list})
         qt_get_library_with_link_flag(lib_name_with_link_flag "${library_path}")
         if(lib_name_with_link_flag)
+            get_filename_component(dir "${library_path}" DIRECTORY)
+            # If library_path isn't in default link directories, we should add it to link flags.
+            list(FIND IMPLICIT_LINK_DIRECTORIES ${dir} index)
+            if(${index} EQUAL -1)
+                list(APPEND out_list "-L${dir} ")
+            endif()
             list(APPEND out_list "${lib_name_with_link_flag}")
         else()
             list(APPEND out_list "${library_path}")
diff --git a/cmake/QtGenerateLibPri.cmake b/cmake/QtGenerateLibPri.cmake
index f5763899e6..3c5e860e16 100644
--- a/cmake/QtGenerateLibPri.cmake
+++ b/cmake/QtGenerateLibPri.cmake
@@ -7,6 +7,7 @@
 # LIBRARY_SUFFIXES: list of known library extensions, e.g. .so;.a on Linux
 # LIBRARY_PREFIXES: list of known library prefies, e.g. the "lib" in "libz" on on Linux
 # LINK_LIBRARY_FLAG: flag used to link a shared library to an executable, e.g. -l on UNIX
+# IMPLICIT_LINK_DIRECTORIES: list of implicit linker search paths
 #
 # QMAKE_LIBS_XXX values are split into QMAKE_LIBS_XXX_DEBUG and QMAKE_LIBS_XXX_RELEASE if
 # debug_and_release was detected. The CMake configuration "Debug" is considered for the _DEBUG
diff --git a/cmake/QtPriHelpers.cmake b/cmake/QtPriHelpers.cmake
index 5498b8a904..abe03031ad 100644
--- a/cmake/QtPriHelpers.cmake
+++ b/cmake/QtPriHelpers.cmake
@@ -55,8 +55,10 @@ function(qt_generate_qmake_libraries_pri_content module_name output_root_dir out
         endforeach()
 
         # Filter out implicit include directories
-        string(PREPEND lib_incdir "$<FILTER:")
-        string(APPEND lib_incdir ",EXCLUDE,${implicit_include_dirs_regex}>")
+        if(implicit_include_dirs_regex)
+            string(PREPEND lib_incdir "$<FILTER:")
+            string(APPEND lib_incdir ",EXCLUDE,${implicit_include_dirs_regex}>")
+        endif()
 
         set(uccfg $<UPPER_CASE:$<CONFIG>>)
         string(APPEND content "list(APPEND known_libs ${uclib})
@@ -375,6 +377,11 @@ QT.${config_module_name}_private.disabled_features = ${disabled_private_features
             ${CMAKE_SHARED_LIBRARY_SUFFIX}
             ${CMAKE_EXTRA_SHARED_LIBRARY_SUFFIXES}
             ${CMAKE_STATIC_LIBRARY_SUFFIX})
+        if(MSVC)
+            set(link_library_flag "-l")
+        else()
+            set(link_library_flag ${CMAKE_LINK_LIBRARY_FLAG})
+        endif()
         add_custom_command(
             OUTPUT "${private_pri_file_path}"
             DEPENDS ${inputs}
@@ -383,8 +390,9 @@ QT.${config_module_name}_private.disabled_features = ${disabled_private_features
             COMMAND ${CMAKE_COMMAND} "-DIN_FILES=${inputs}" "-DOUT_FILE=${private_pri_file_path}"
                     "-DLIBRARY_PREFIXES=${library_prefixes}"
                     "-DLIBRARY_SUFFIXES=${library_suffixes}"
-                    "-DLINK_LIBRARY_FLAG=${CMAKE_LINK_LIBRARY_FLAG}"
+                    "-DLINK_LIBRARY_FLAG=${link_library_flag}"
                     "-DCONFIGS=${configs}"
+                    "-DIMPLICIT_LINK_DIRECTORIES=${CMAKE_CXX_IMPLICIT_LINK_DIRECTORIES}"
                     -P "${QT_CMAKE_DIR}/QtGenerateLibPri.cmake"
             VERBATIM)
         add_custom_target(${target}_lib_pri DEPENDS "${private_pri_file_path}")
@@ -782,6 +790,11 @@ CONFIG += ${private_config_joined}
         ${CMAKE_SHARED_LIBRARY_SUFFIX}
         ${CMAKE_EXTRA_SHARED_LIBRARY_SUFFIXES}
         ${CMAKE_STATIC_LIBRARY_SUFFIX})
+    if(MSVC)
+        set(link_library_flag "-l")
+    else()
+        set(link_library_flag ${CMAKE_LINK_LIBRARY_FLAG})
+    endif()
     add_custom_command(
         OUTPUT "${qmodule_pri_target_path}"
         DEPENDS ${inputs}
@@ -790,8 +803,9 @@ CONFIG += ${private_config_joined}
         COMMAND ${CMAKE_COMMAND} "-DIN_FILES=${inputs}" "-DOUT_FILE=${qmodule_pri_target_path}"
                 "-DLIBRARY_PREFIXES=${library_prefixes}"
                 "-DLIBRARY_SUFFIXES=${library_suffixes}"
-                "-DLINK_LIBRARY_FLAG=${CMAKE_LINK_LIBRARY_FLAG}"
+                "-DLINK_LIBRARY_FLAG=${link_library_flag}"
                 "-DCONFIGS=${configs}"
+                "-DIMPLICIT_LINK_DIRECTORIES=${CMAKE_CXX_IMPLICIT_LINK_DIRECTORIES}"
                 -P "${QT_CMAKE_DIR}/QtGenerateLibPri.cmake"
         VERBATIM)
     add_custom_target(qmodule_pri DEPENDS "${qmodule_pri_target_path}")
diff --git a/cmake/QtPrlHelpers.cmake b/cmake/QtPrlHelpers.cmake
index 0aab301053..9e830827a0 100644
--- a/cmake/QtPrlHelpers.cmake
+++ b/cmake/QtPrlHelpers.cmake
@@ -379,6 +379,11 @@ ${prl_step1_content_libs}
         qt_path_join(prl_meta_info_path
                      "${CMAKE_CURRENT_BINARY_DIR}"
                      "${prl_meta_info_name_prefix}${config}${prl_meta_info_name_suffix}")
+        if(MSVC)
+            set(link_library_flag "-l")
+        else()
+            set(link_library_flag ${CMAKE_LINK_LIBRARY_FLAG})
+        endif()
         add_custom_command(
             OUTPUT  "${prl_step2_path}"
             DEPENDS "${prl_step1_path}"
@@ -391,8 +396,9 @@ ${prl_step1_content_libs}
                     "-DOUT_FILE=${prl_step2_path}"
                     "-DLIBRARY_PREFIXES=${library_prefixes}"
                     "-DLIBRARY_SUFFIXES=${library_suffixes}"
-                    "-DLINK_LIBRARY_FLAG=${CMAKE_LINK_LIBRARY_FLAG}"
+                    "-DLINK_LIBRARY_FLAG=${link_library_flag}"
                     "-DQT_LIB_DIRS=${qt_lib_dirs}"
+                    "-DIMPLICIT_LINK_DIRECTORIES=${CMAKE_CXX_IMPLICIT_LINK_DIRECTORIES}"
                     -P "${QT_CMAKE_DIR}/QtFinishPrlFile.cmake"
             VERBATIM
             COMMENT "Generating prl file for target ${target}"