From d6e01ae05c3695aaf7d0d434718154b6ff151e32 Mon Sep 17 00:00:00 2001
From: Joerg Bornemann <joerg.bornemann@qt.io>
Date: Tue, 22 Jun 2021 16:00:03 +0200
Subject: [PATCH] Fix QT_HOST_DATA for builds setting INSTALL_MKSPECSDIR

In a Qt build that was configured with INSTALL_MKSPECSDIR set to
something different than INSTALL_DATADIR, the qmake property
QT_HOST_DATA was wrong. Consequently, mkspecs could not be loaded,
rendering qmake dysfunctional.

The reason was that we considered every QT_HOST_xxx property to have the
same value as QT_INSTALL_xxx in a non-cross build.
This is not true for QT_HOST_DATA, because users might want to set
INSTALL_DATADIR to "foo" but INSTALL_MKSPECSDIR to "bar/mkspecs".

Move the unused determination of the host data dir to the QtLibraryInfo
lib and handle QT_HOST_DATA specially.

Fixes: QTBUG-94591
Pick-to: 6.2
Change-Id: I2c44cda8405ff1d14391254fcd1d9b1361cb5855
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
---
 cmake/QtQmakeHelpers.cmake | 6 ------
 qmake/CMakeLists.txt       | 8 ++++++++
 qmake/qmakelibraryinfo.cpp | 7 ++++++-
 3 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/cmake/QtQmakeHelpers.cmake b/cmake/QtQmakeHelpers.cmake
index 0a2c5b1531..47a41d9236 100644
--- a/cmake/QtQmakeHelpers.cmake
+++ b/cmake/QtQmakeHelpers.cmake
@@ -25,12 +25,6 @@ function(qt_generate_qconfig_cpp in_file out_file)
     set(QT_CONFIG_STR_OFFSETS "")
     set(QT_CONFIG_STRS "")
 
-    # Chop off the "/mkspecs" part of INSTALL_MKSPECSDIR
-    get_filename_component(hostdatadir "${INSTALL_MKSPECSDIR}" DIRECTORY)
-    if("${hostdatadir}" STREQUAL "")
-        set(hostdatadir ".")
-    endif()
-
     # Start first part.
     qt_add_string_to_qconfig_cpp("${INSTALL_DOCDIR}")
     qt_add_string_to_qconfig_cpp("${INSTALL_INCLUDEDIR}")
diff --git a/qmake/CMakeLists.txt b/qmake/CMakeLists.txt
index dbe50552cf..d35d981c99 100644
--- a/qmake/CMakeLists.txt
+++ b/qmake/CMakeLists.txt
@@ -22,6 +22,13 @@ target_include_directories(QtLibraryInfo PUBLIC
     "${CMAKE_CURRENT_SOURCE_DIR}"
     "${CMAKE_CURRENT_SOURCE_DIR}/library"
 )
+
+# Chop off the "/mkspecs" part of INSTALL_MKSPECSDIR
+get_filename_component(hostdatadir "${INSTALL_MKSPECSDIR}" DIRECTORY)
+if("${hostdatadir}" STREQUAL "")
+    set(hostdatadir ".")
+endif()
+
 target_compile_definitions(QtLibraryInfo PUBLIC
     PROEVALUATOR_FULL
     QT_BUILD_QMAKE
@@ -33,6 +40,7 @@ target_compile_definitions(QtLibraryInfo PUBLIC
     QT_VERSION_PATCH=${PROJECT_VERSION_PATCH} # special case
     QT_HOST_MKSPEC="${QT_QMAKE_HOST_MKSPEC}"
     QT_TARGET_MKSPEC="${QT_QMAKE_TARGET_MKSPEC}"
+    QT_HOST_DATADIR="${hostdatadir}"
 )
 qt_set_common_target_properties(QtLibraryInfo)
 
diff --git a/qmake/qmakelibraryinfo.cpp b/qmake/qmakelibraryinfo.cpp
index 257d23cbb6..b501cfc5f6 100644
--- a/qmake/qmakelibraryinfo.cpp
+++ b/qmake/qmakelibraryinfo.cpp
@@ -182,7 +182,12 @@ static QString storedPath(int loc)
     if (loc < QMakeLibraryInfo::FirstHostPath) {
         result = QLibraryInfo::path(static_cast<QLibraryInfo::LibraryPath>(loc));
     } else if (loc <= QMakeLibraryInfo::LastHostPath) {
-        result = QLibraryInfo::path(hostToTargetPathEnum(loc));
+        if (loc == QMakeLibraryInfo::HostDataPath) {
+            // Handle QT_HOST_DATADIR specially. It is not necessarily equal to QT_INSTALL_DATA.
+            result = QT_HOST_DATADIR;
+        } else {
+            result = QLibraryInfo::path(hostToTargetPathEnum(loc));
+        }
     } else if (loc == QMakeLibraryInfo::SysrootPath) {
         // empty result
     } else if (loc == QMakeLibraryInfo::SysrootifyPrefixPath) {