Add support/migration towards Qt 6.x?

[jfshorter]

Hello all,

Qt5 can be problematic for some Linux distributions now migrating towards Qt6 for core OS tools, might be worth adding support to cover eventual migration.

Thankfully it is a relatively small set of changes to get it to build.
However, a couple consequential changes required due to compiler upgrade to satisfy Qt6, libboost and core library header changes to all build cleanly.

Note: Happy to try and figure out pull requests and make it Qt5 and Qt6 conditional. Although I am not a seasoned with CMake & GitHub user, so apologies in advance!

Requirements imposed by ~Qt 6 and later:

• GCC >= 8 - Knock on consequences later for OpenROAD/libboost.
• Remapping QRegExp to QRegularExpression, re-wrapping regular expression building & matching calls.
• Fix includes for resolving QFile and changed location of QOpenGLWidget.
• Initial window sizing due to class changes.

diff --git a/src/gui/CMakeLists.txt b/src/gui/CMakeLists.txt
index 21ff0d7ff..238900d8a 100755
--- a/src/gui/CMakeLists.txt
+++ b/src/gui/CMakeLists.txt
@@ -3,12 +3,12 @@ option(BUILD_GUI "Build the GUI" ON)
 
 # If Qt is not installed there will not be cmake
 # support for the package so this needs to be "quiet".
-find_package(Qt5 QUIET COMPONENTS Core Widgets)
+find_package(Qt6 QUIET COMPONENTS Core Widgets)
 
 include("openroad")
 set(CMAKE_INCLUDE_CURRENT_DIR ON)
 
-if (Qt5_FOUND AND BUILD_GUI)
+if (Qt6_FOUND AND BUILD_GUI)
   message(STATUS "GUI is enabled")
   set(CMAKE_AUTOMOC ON)
   set(CMAKE_AUTORCC ON)
@@ -53,8 +53,8 @@ if (Qt5_FOUND AND BUILD_GUI)
     PUBLIC
       odb
     PRIVATE
-      Qt5::Core
-      Qt5::Widgets
+      Qt6::Core
+      Qt6::Widgets
       utl
       Boost::boost
   )
diff --git a/src/gui/src/displayControls.cpp b/src/gui/src/displayControls.cpp
index 69cc0b634..700b41c74 100644
--- a/src/gui/src/displayControls.cpp
+++ b/src/gui/src/displayControls.cpp
@@ -36,7 +36,7 @@
 #include <QKeyEvent>
 #include <QLineEdit>
 #include <QPainter>
-#include <QRegExp>
+#include <QRegularExpression>
 #include <QSettings>
 #include <QVBoxLayout>
 #include <vector>
@@ -795,9 +795,9 @@ void DisplayControls::findControlsInItems(const std::string& path,
   std::map<std::string, QStandardItem*> controls;
   collectControls(model_->invisibleRootItem(), column, controls);
 
-  const QRegExp path_compare(QString::fromStdString(path), Qt::CaseInsensitive, QRegExp::Wildcard);
+  const QRegularExpression path_compare(QRegularExpression::wildcardToRegularExpression(QString::fromStdString(path), QRegularExpression::UnanchoredWildcardConversion) , QRegularExpression::CaseInsensitiveOption);
   for (auto& [item_path, item] : controls) {
-    if (path_compare.exactMatch(QString::fromStdString(item_path))) {
+    if (path_compare.match(QString::fromStdString(item_path)).hasMatch()) {
       items.push_back(item);
     }
   }
diff --git a/src/gui/src/gui.cpp b/src/gui/src/gui.cpp
index 792ed56a8..73a877d0c 100644
--- a/src/gui/src/gui.cpp
+++ b/src/gui/src/gui.cpp
@@ -268,12 +268,11 @@ void Gui::select(const std::string& type, const std::string& name_filter, bool f
           // convert to vector
           std::vector<Selected> selected_vector(selected.begin(), selected.end());
           // remove elements
-          QRegExp reg_filter(QString::fromStdString(name_filter),
-                             filter_case_sensitive ? Qt::CaseSensitive : Qt::CaseInsensitive,
-                             QRegExp::Wildcard);
+          QRegularExpression reg_filter(QRegularExpression::wildcardToRegularExpression(QString::fromStdString(name_filter), QRegularExpression::UnanchoredWildcardConversion),
+                             filter_case_sensitive ? QRegularExpression::NoPatternOption : QRegularExpression::CaseInsensitiveOption);
           auto remove_if = std::remove_if(selected_vector.begin(), selected_vector.end(),
               [&reg_filter](auto sel) -> bool {
-                return !reg_filter.exactMatch(QString::fromStdString(sel.getName()));
+                return !reg_filter.match(QString::fromStdString(sel.getName())).hasMatch();
               });
           selected_vector.erase(remove_if, selected_vector.end());
           // rebuild selectionset
diff --git a/src/gui/src/layoutViewer.cpp b/src/gui/src/layoutViewer.cpp
index b5df82c8d..708744533 100644
--- a/src/gui/src/layoutViewer.cpp
+++ b/src/gui/src/layoutViewer.cpp
@@ -166,8 +166,8 @@ class GuiPainter : public Painter
   void drawRect(const odb::Rect& rect, int roundX = 0, int roundY = 0) override
   {
     if (roundX > 0 || roundY > 0)
-      painter_->drawRoundRect(QRect(QPoint(rect.xMin(), rect.yMin()),
-                                    QPoint(rect.xMax(), rect.yMax())),
+      painter_->drawRoundedRect(QRect(QPoint(rect.xMin(), rect.yMin()),
+                                      QPoint(rect.xMax(), rect.yMax())),
                               roundX,
                               roundY);
     else
diff --git a/src/gui/src/layoutViewer.h b/src/gui/src/layoutViewer.h
index f746a0fd0..4f4744e10 100755
--- a/src/gui/src/layoutViewer.h
+++ b/src/gui/src/layoutViewer.h
@@ -37,7 +37,7 @@
 #include <QMainWindow>
 #include <QMap>
 #include <QMenu>
-#include <QOpenGLWidget>
+#include <QtOpenGLWidgets/QOpenGLWidget>
 #include <QPixmap>
 #include <QScrollArea>
 #include <QShortcut>
diff --git a/src/gui/src/mainWindow.cpp b/src/gui/src/mainWindow.cpp
index daf2b1a4a..a5d49952a 100644
--- a/src/gui/src/mainWindow.cpp
+++ b/src/gui/src/mainWindow.cpp
@@ -31,7 +31,7 @@
 // POSSIBILITY OF SUCH DAMAGE.
 
 #include <QDesktopServices>
-#include <QDesktopWidget>
+#include <QScreen>
 #include <QInputDialog>
 #include <QMenu>
 #include <QMenuBar>
@@ -86,9 +86,7 @@ MainWindow::MainWindow(QWidget* parent)
       drc_viewer_(new DRCWidget(this))
 {
   // Size and position the window
-  QSize size = QDesktopWidget().availableGeometry(this).size();
-  resize(size * 0.8);
-  move(size.width() * 0.1, size.height() * 0.1);
+  resize(QGuiApplication::primaryScreen()->availableGeometry().size() * 0.8);
 
   find_dialog_ = new FindObjectDialog(this);
diff --git a/src/gui/src/tclCmdInputWidget.cpp b/src/gui/src/tclCmdInputWidget.cpp
index 316db6529..5584e9eee 100644
--- a/src/gui/src/tclCmdInputWidget.cpp
+++ b/src/gui/src/tclCmdInputWidget.cpp
@@ -34,6 +34,7 @@
 
 #include <regex>
 
+#include <QFile>
 #include <QAbstractItemView>
 #include <QMimeData>
 #include <QScrollBar>

Requirements unrelated to Qt6 for build to work imposed by libboost 1.11 / GCC-13 (Happy to be corrected):

• A few includes now required for geometry classes/objects explicitly to avoid compiler errors.
• Modern GCC imposed: cstdint (uint_*t types got separated) & memory (std::shared_ptr got moved).
• Compiler complains that the pointer deference cannot be guaranteed constant for the STA LibertyLibrary objects.

diff --git a/src/gui/src/ruler.cpp b/src/gui/src/ruler.cpp
index 14da6a520..ae5652605 100644
--- a/src/gui/src/ruler.cpp
+++ b/src/gui/src/ruler.cpp
@@ -34,6 +34,8 @@
 #include "ruler.h"
 
 #include <boost/geometry.hpp>
+#include <boost/geometry/geometries/geometries.hpp>
+#include <boost/geometry/geometries/point_xy.hpp>
 
 namespace gui {
 
diff --git a/src/gui/src/search.h b/src/gui/src/search.h
index 266fc0b40..d358f820a 100644
--- a/src/gui/src/search.h
+++ b/src/gui/src/search.h
@@ -34,6 +34,8 @@
 
 #include <boost/geometry.hpp>
 #include <boost/geometry/index/rtree.hpp>
+#include <boost/geometry/geometries/geometries.hpp>
+#include <boost/geometry/geometries/point_xy.hpp>
 
 #include "db.h"
diff --git a/src/mpl/src/ParquetFP/src/SolveMulti.cxx b/src/mpl/src/ParquetFP/src/SolveMulti.cxx
index 0c8b91ff5..90b004f94 100644
--- a/src/mpl/src/ParquetFP/src/SolveMulti.cxx
+++ b/src/mpl/src/ParquetFP/src/SolveMulti.cxx
@@ -31,7 +31,7 @@
 ***************************************************************************/
 
 #include "SolveMulti.h"
-
+#include <memory> //std:unique_ptr
 #include "Annealer.h"
 #include "ClusterDB.h"
 #include "CommandLine.h"
diff --git a/src/odb/include/odb/dbStream.h b/src/odb/include/odb/dbStream.h
index 100e0bb43..d18c8db8f 100644
--- a/src/odb/include/odb/dbStream.h
+++ b/src/odb/include/odb/dbStream.h
@@ -33,7 +33,7 @@
 #pragma once
 
 #include <string.h>
-
+#include <cstdint>
 #include <string>
 
 #include "ZException.h"
diff --git a/src/par/src/PartitionNetwork.cpp b/src/par/src/PartitionNetwork.cpp
index 39033b46d..0cc818a23 100644
--- a/src/par/src/PartitionNetwork.cpp
+++ b/src/par/src/PartitionNetwork.cpp
@@ -143,7 +143,7 @@ static void determineLibraryBrackets(const dbNetwork* db_network,
 
   sta::LibertyLibraryIterator* lib_iter = db_network->libertyLibraryIterator();
   while (lib_iter->hasNext()) {
-    const sta::LibertyLibrary* lib = lib_iter->next();
+    sta::LibertyLibrary* lib = lib_iter->next();
     *left = lib->busBrktLeft();
     *right = lib->busBrktRight();
   }

Kind regards,
Jim

[maliberty]

We were stuck with qt5 while supporting Centos7. Now that we have dropped it we could just migrate to qt6 as most OS support it. If you want to make a PR for a straight conversion that would be great.

[QuantamHD]

Google is still on QT 5 we would need a few months at least to upgrade everything that uses qt5.

[maliberty]

@QuantamHD every project at Google has to use migrate at once? Even with a mono repo you could have separate packages.

[QuantamHD]

One version policy at Google means everything has to go at once

[maliberty]

@jfshorter if you can do version switching I guess that would be best.

[jfshorter]

Apologies for the long delay replying:
I had a couple system lib clashes and issues building natively + locally on top of OpenSuSE Leap 15.6 stable.
Therefore went back to basics in a fully clean system, but the upside is now learnt new tools*1 to make package building much safer! :D

@QuantamHD Understand with long serving infrastructure from experience.
Currently the minimal differences are small enough to not completely destroy the code base with conditionals.
My thought is if it were to affect more than these couple of items it would cause a divergence of pain but thankfully it is not too bad right now.

@maliberty No problems, I suspected this would be the case as not everyone will be running bleeding edge anyway.

Now I finally have the issues fixed will update my fork and get a pull request in place.
Thanks for your patience!

[1] - Chosen distrobox + podman as this will also ensure matching set up on top of Open Build Service with the view to making direct RPM builds. Also supports Docker, so will experiment with the CI flow once I get chance.