Add QtPdf iOS builds

QtPDf iOS builds must support fat libs builds. Compared
to 5.15 however this is done differently. Before we tweaked gn
to compile multi arch with 'Xarch' parameter. This had few
downsides as we could not determine which arch/cpu compiles
given file as compilation was opaque to gn. The current approach is
to follow mac universal builds, compile builds separately for each
architecture and lipo the outcome. However, this introduces some
issues as ios builds are static builds and creating lipo archive
will gather object files, which should end up in final QtPdf lib
instead. Therefore create multi arch object file instead of archive
and use this one.

Note the compiler now uses arch triple for Pdfium as Chromium does,
however qt files still use 'arch' and '*-version-min' combination.

Task-number: QTBUG-88614
Pick-to: 6.3 6.2
Change-Id: I7775c8b4d1554df497eb61fa6187f12c00b9032d
Reviewed-by: Peter Varga <pvarga@inf.u-szeged.hu>

4 files changed, 126 insertions, 24 deletions

diff --git a/cmake/Functions.cmake b/cmake/Functions.cmake
index 7d3dd493c..ab151c329 100644
--- a/cmake/Functions.cmake
+++ b/cmake/Functions.cmake
@@ -345,6 +345,14 @@ function(get_darwin_sdk_version result)
     endif()
 endfunction()
 
+function(get_ios_target_triple_and_sysroot result arch)
+    get_ios_sysroot(sysroot ${arch})
+    set(${result}
+        -target ${arch}-apple-ios${CMAKE_OSX_DEPLOYMENT_TARGET}
+        -isysroot ${sysroot} PARENT_SCOPE
+    )
+endfunction()
+
 function(add_ninja_target target cmakeTarget ninjaTarget config arch buildDir)
     string(TOUPPER ${config} cfg)
     add_custom_target(${target} DEPENDS ${buildDir}/${config}/${arch}/${ninjaTarget}.stamp)
@@ -464,36 +472,86 @@ function(add_rsp_command target buildDir completeStatic)
     )
 endfunction()
 
-function(add_lipo_command target buildDir)
+function(add_ios_rsp_command target buildDir completeStatic)
     get_target_property(config ${target} CONFIG)
+    get_target_property(arch ${target} ARCH)
+    get_target_property(ninjaTarget ${target} NINJA_TARGET)
     get_target_property(cmakeTarget ${target} CMAKE_TARGET)
-    set(libs_rsp "${buildDir}/x86_64/${ninjaTarget}_libs.rsp")
-    # Lipo the object files together to a single fat archive
-    add_library(${cmakeTarget}_${config} STATIC IMPORTED GLOBAL)
+    string(TOUPPER ${config} cfg)
+    get_ios_target_triple_and_sysroot(args ${arch})
+    set(objects_rsp "${buildDir}/${ninjaTarget}_objects.rsp")
+    set(objects_out "${buildDir}/${cmakeTarget}_objects.o")
     add_custom_command(
-        OUTPUT ${buildDir}/lib${cmakeTarget}.a
-        COMMAND lipo -create
-            -output ${buildDir}/lib${cmakeTarget}.a
-        ARGS
-            ${buildDir}/arm64/${cmakeTarget}.a
-            ${buildDir}/x86_64/${cmakeTarget}.a
+        OUTPUT ${objects_out}
+        COMMAND clang++ -r -nostdlib
+            ${args}
+            -o ${objects_out}
+            -Wl,-keep_private_externs
+            @${objects_rsp}
         DEPENDS
-            ${buildDir}/arm64/${cmakeTarget}.a
-            ${buildDir}/x86_64/${cmakeTarget}.a
+            ${buildDir}/${ninjaTarget}.stamp
+        WORKING_DIRECTORY "${buildDir}/../../.."
+        COMMENT "Creating intermediate object files for ${cmakeTarget}/${config}/${arch}"
         USES_TERMINAL
         VERBATIM
+        COMMAND_EXPAND_LISTS
     )
+endfunction()
+
+# Lipo the object files together to a single fat archive
+function(create_lipo_command target buildDir fileName)
+    get_target_property(config ${target} CONFIG)
+    get_architectures(archs)
+    foreach(arch ${archs})
+        list(APPEND lipo_objects ${buildDir}/${arch}/${fileName})
+    endforeach()
+    add_custom_command(
+        OUTPUT ${buildDir}/${fileName}
+        COMMAND lipo -create
+            -output ${buildDir}/${fileName}
+        ARGS ${lipo_objects}
+        DEPENDS ${lipo_objects}
+        USES_TERMINAL
+        COMMENT "Running lipo for ${target}/${config}/${arch}"
+        VERBATIM
+    )
+endfunction()
+
+# this function only deals with objects as it is only
+# used by qtpdf and we do not need anything more
+function(add_ios_lipo_command target buildDir)
+    get_target_property(config ${target} CONFIG)
+    get_target_property(cmakeTarget ${target} CMAKE_TARGET)
+    set(fileName ${cmakeTarget}_objects.o)
+    create_lipo_command(${target} ${buildDir} ${fileName})
+    add_custom_target(lipo_${cmakeTarget}_${config} DEPENDS
+        ${buildDir}/${fileName}
+    )
+    add_dependencies(${cmakeTarget} lipo_${cmakeTarget}_${config})
+    qt_internal_get_target_property(options ${cmakeTarget} STATIC_LIBRARY_OPTIONS)
+    set_target_properties(${cmakeTarget} PROPERTIES STATIC_LIBRARY_OPTIONS
+        "${options}$<$<CONFIG:${config}>:${buildDir}/${fileName}>"
+    )
+endfunction()
+
+function(add_lipo_command target buildDir)
+    get_target_property(config ${target} CONFIG)
+    get_target_property(cmakeTarget ${target} CMAKE_TARGET)
+    set(fileName ${cmakeTarget}.a)
+    create_lipo_command(${target} ${buildDir} ${fileName})
+    add_library(${cmakeTarget}_${config} STATIC IMPORTED GLOBAL)
     set_property(TARGET ${cmakeTarget}_${config}
-        PROPERTY IMPORTED_LOCATION ${buildDir}/lib${cmakeTarget}.a
+        PROPERTY IMPORTED_LOCATION ${buildDir}/${fileName}
     )
     add_custom_target(lipo_${cmakeTarget}_${config} DEPENDS
-        ${buildDir}/lib${cmakeTarget}.a
+        ${buildDir}/${fileName}
     )
     add_dependencies(${cmakeTarget}_${config} lipo_${cmakeTarget}_${config})
     target_link_libraries(${cmakeTarget} PRIVATE ${cmakeTarget}_${config})
 
     # Just link with dynamic libs once
     # TODO: this is evil hack, since cmake has no idea about libs
+    set(libs_rsp "${buildDir}/x86_64/${ninjaTarget}_libs.rsp")
     target_link_options(${cmakeTarget} PRIVATE "$<$<CONFIG:${config}>:@${libs_rsp}>")
 endfunction()
 
@@ -580,6 +638,19 @@ function(get_gn_is_clang result)
     endif()
 endfunction()
 
+function(get_ios_sysroot result arch)
+    if(NOT CMAKE_APPLE_ARCH_SYSROOTS)
+      message(FATAL_ERROR "CMAKE_APPLE_ARCH_SYSROOTS not set.")
+    endif()
+    get_architectures(archs)
+    list(FIND archs ${arch} known_arch)
+    if (known_arch EQUAL "-1")
+        message(FATAL_ERROR "Unknown iOS architecture ${arch}.")
+    endif()
+    list(GET CMAKE_APPLE_ARCH_SYSROOTS ${known_arch} sysroot)
+    set(${result} ${sysroot} PARENT_SCOPE)
+endfunction()
+
 function(configure_gn_toolchain name binTargetCpu v8TargetCpu toolchainIn toolchainOut)
     set(GN_TOOLCHAIN ${name})
     get_gn_os(GN_OS)
@@ -727,7 +798,8 @@ macro(append_build_type_setup)
         CONDITION FEATURE_developer_build
     )
 
-    if(NOT QT_FEATURE_webengine_full_debug_info)
+    #TODO: refactor to not check for IOS here
+    if(NOT QT_FEATURE_webengine_full_debug_info AND NOT IOS)
         list(APPEND gnArgArg blink_symbol_level=0 remove_v8base_debug_symbols=true)
     endif()
 
@@ -779,6 +851,14 @@ macro(append_compiler_linker_sdk_setup)
                 mac_sdk_min="${macSdkVersion}"
             )
         endif()
+        if(IOS)
+            list(APPEND gnArgArg
+                use_system_xcode=true
+                enable_ios_bitcode=true
+                ios_deployment_target="${CMAKE_OSX_DEPLOYMENT_TARGET}"
+                ios_enable_code_signing=false
+            )
+        endif()
     else()
         if(QT_FEATURE_use_lld_linker)
             get_filename_component(clangBasePath ${CMAKE_LINKER} DIRECTORY)
@@ -887,6 +967,10 @@ macro(append_toolchain_setup)
     else()
         get_gn_arch(cpu ${arch})
         list(APPEND gnArgArg target_cpu="${cpu}")
+        if(IOS)
+            get_ios_sysroot(sysroot ${arch})
+            list(APPEND gnArgArg target_sysroot="${sysroot}" target_os="ios")
+        endif()
     endif()
 endmacro()
 
@@ -932,10 +1016,10 @@ function(get_configs result)
 endfunction()
 
 function(get_architectures result)
-    if(NOT QT_IS_MACOS_UNIVERSAL)
-        set(${result} ${CMAKE_SYSTEM_PROCESSOR} PARENT_SCOPE)
-    else()
+    if(QT_IS_MACOS_UNIVERSAL OR IOS)
         set(${result} ${CMAKE_OSX_ARCHITECTURES} PARENT_SCOPE)
+    else()
+        set(${result} ${CMAKE_SYSTEM_PROCESSOR} PARENT_SCOPE)
     endif()
 endfunction()
 
@@ -967,6 +1051,8 @@ function(add_gn_build_aritfacts_to_target cmakeTarget ninjaTarget module buildDi
             )
             if(QT_IS_MACOS_UNIVERSAL)
                 add_rsp_command(${target} ${buildDir}/${config}/${arch} ${completeStatic})
+            elseif(IOS)
+                add_ios_rsp_command(${target} ${buildDir}/${config}/${arch} ${completeStatic})
             else()
                 extend_cmake_target(${target} ${buildDir}/${config}/${arch} ${completeStatic})
             endif()
@@ -976,6 +1062,11 @@ function(add_gn_build_aritfacts_to_target cmakeTarget ninjaTarget module buildDi
             set(target ${ninjaTarget}_${config}_${arch})
             add_lipo_command(${target} ${buildDir}/${config})
         endif()
+        if(IOS)
+            list(GET archs 0 arch)
+            set(target ${ninjaTarget}_${config}_${arch})
+            add_ios_lipo_command(${target} ${buildDir}/${config})
+        endif()
     endforeach()
 endfunction()
 
diff --git a/configure.cmake b/configure.cmake
index 397f51f70..86428d880 100644
--- a/configure.cmake
+++ b/configure.cmake
@@ -371,10 +371,15 @@ assertTargets(
    TARGETS Gui Quick Qml
 )
 add_check_for_support(
-   MODULES QtWebEngine QtPdf
+   MODULES QtWebEngine
    CONDITION LINUX OR (WIN32 AND NOT WIN_ARM_64) OR (MACOS AND NOT CMAKE_CROSSCOMPILING)
    MESSAGE "Build can be done only on Linux, Windows or macOS."
 )
+add_check_for_support(
+   MODULES QtPdf
+   CONDITION LINUX OR (WIN32 AND NOT WIN_ARM_64) OR (MACOS AND NOT CMAKE_CROSSCOMPILING) OR IOS
+   MESSAGE "Build can be done only on Linux, Windows, macOS or iOS."
+)
 if(LINUX AND CMAKE_CROSSCOMPILING)
    get_gn_arch(testArch ${TEST_architecture_arch})
    add_check_for_support(
@@ -384,7 +389,7 @@ if(LINUX AND CMAKE_CROSSCOMPILING)
    )
 endif()
 add_check_for_support(
-   MODULES QtWebEngine QtPdf
+   MODULES QtWebEngine
    CONDITION NOT QT_FEATURE_static
    MESSAGE "Static build is not supported."
 )
@@ -476,7 +481,8 @@ add_check_for_support(
        (WIN32 AND CMAKE_CXX_COMPILER_ID STREQUAL MSVC) OR
        (WIN32 AND CMAKE_CXX_COMPILER_ID STREQUAL Clang AND
           CMAKE_CXX_SIMULATE_ID STREQUAL MSVC) OR
-       (MACOS AND CMAKE_CXX_COMPILER_ID STREQUAL AppleClang)
+       (MACOS AND CMAKE_CXX_COMPILER_ID STREQUAL AppleClang) OR
+       (APPLE AND CMAKE_CXX_COMPILER_ID STREQUAL AppleClang)
    MESSAGE "${CMAKE_CXX_COMPILER_ID} compiler is not supported."
 )
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 5ba4cb1c6..227e1186e 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -117,6 +117,10 @@ endif()
 #  GN PROJECT
 ##
 
+if(CMAKE_CROSSCOMPILING AND NOT Gn_FOUND)
+   message(FATAL_ERROR "No gn found for cross-compilation")
+endif()
+
 if(NOT Gn_FOUND)
     externalproject_add(gn
         SOURCE_DIR  ${CMAKE_CURRENT_LIST_DIR}/gn
@@ -145,7 +149,7 @@ endif()
 #  HOST PROJECT
 ##
 
-if(CMAKE_CROSSCOMPILING)
+if(CMAKE_CROSSCOMPILING AND NOT IOS)
 
     if(NOT Gn_FOUND)
         message(FATAL_ERROR "\nHost gn not found - cross compilation not possible")
@@ -175,7 +179,7 @@ if(CMAKE_CROSSCOMPILING)
 endif()
 
 # install gn for cross build
-if(LINUX AND INSTALL_GN)
+if((LINUX OR MACOS) AND INSTALL_GN)
     get_install_config(installConfig)
     install(
         PROGRAMS ${installDir}/bin/gn
diff --git a/src/pdf/CMakeLists.txt b/src/pdf/CMakeLists.txt
index 675a2ad19..b572b3155 100644
--- a/src/pdf/CMakeLists.txt
+++ b/src/pdf/CMakeLists.txt
@@ -7,7 +7,6 @@ if(PkgConfig_FOUND)
 endif()
 
 set(buildDir "${CMAKE_CURRENT_BINARY_DIR}")
-add_subdirectory(plugins/imageformats/pdf)
 
 ##
 #  PDF MODULE
@@ -40,6 +39,8 @@ qt_internal_add_module(Pdf
         Qt::Gui
 )
 
+add_subdirectory(plugins/imageformats/pdf)
+
 ##
 #  PDF DOCS
 ##