Merge remote-tracking branch 'origin/master' into redist_slack

8 files changed, 654 insertions, 378 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index cc712e72..41bd4aab 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -58,9 +58,9 @@ if (BUILD_GUI AND NOT BUILD_PYTHON)
     message(FATAL_ERROR "GUI requires Python to build")
 endif()
 
+find_package(PythonInterp 3.5 REQUIRED)
 if (BUILD_PYTHON)
     # TODO: sensible minimum Python version
-    find_package(PythonInterp 3.5 REQUIRED)
     find_package(PythonLibs 3.5 REQUIRED)
 else()
     add_definitions("-DNO_PYTHON")
diff --git a/README.md b/README.md
index da38500d..dfe2af37 100644
--- a/README.md
+++ b/README.md
@@ -1,87 +1,152 @@
 nextpnr -- a portable FPGA place and route tool
 ===============================================
 
-Supported Architectures
------------------------
+nextpnr is an FPGA place and route tool with emphasis on supporting a wide
+range of real-world FPGA devices. It currently supports Lattice iCE40 devices
+and Lattice ECP5 devices, as well as a "generic" back-end for user-defined
+architectures. (ECP5 and "generic" support are still experimental.)
 
-- iCE40
-- ECP5
+Prerequisites
+-------------
 
-Prequisites
------------
- 
- - CMake 3.3 or later
- - Modern C++11 compiler (`clang-format` required for development)
- - Qt5 or later (`qt5-default` for Ubuntu 16.04)
- - Python 3.5 or later, including development libraries (`python3-dev` for Ubuntu)
-    - on Windows make sure to install same version as supported by [vcpkg](https://github.com/Microsoft/vcpkg/blob/master/ports/python3/CONTROL)
- - Boost libraries (`libboost-dev` or `libboost-all-dev` for Ubuntu)
- - Icestorm, with chipdbs installed in `/usr/local/share/icebox`
- - Latest git Yosys is required to synthesise the demo design
- - For building on Windows with MSVC, usage of vcpkg is advised for dependency installation.
-     - For 32 bit builds: `vcpkg install boost-filesystem boost-program-options boost-thread boost-python qt5-base`
-     - For 64 bit builds: `vcpkg install boost-filesystem:x64-windows boost-program-options:x64-windows boost-thread:x64-windows boost-python:x64-windows qt5-base:x64-windows`
- - For building on macOS, brew utility is needed.
-     - Install all needed packages `brew install cmake python boost boost-python3 qt5`
-     - Do not forget to add qt5 in path as well `echo 'export PATH="/usr/local/opt/qt/bin:$PATH"' >> ~/.bash_profile`
- - For ECP5 support, you must download [Project Trellis](https://github.com/SymbiFlow/prjtrellis), then follow its instructions to
-   download the latest database and build _libtrellis_.
- 
+The following packages need to be installed for building nextpnr, independent
+of the selected architecture:
+
+- CMake 3.3 or later
+- Modern C++11 compiler (`clang-format` required for development)
+- Qt5 or later (`qt5-default` for Ubuntu 16.04)
+- Python 3.5 or later, including development libraries (`python3-dev` for Ubuntu)
+  - on Windows make sure to install same version as supported by [vcpkg](https://github.com/Microsoft/vcpkg/blob/master/ports/python3/CONTROL)
+- Boost libraries (`libboost-dev` or `libboost-all-dev` for Ubuntu)
+- Latest git Yosys is required to synthesise the demo design
+- For building on Windows with MSVC, usage of vcpkg is advised for dependency installation.
+  - For 32 bit builds: `vcpkg install boost-filesystem boost-program-options boost-thread boost-python qt5-base`
+  - For 64 bit builds: `vcpkg install boost-filesystem:x64-windows boost-program-options:x64-windows boost-thread:x64-windows boost-python:x64-windows qt5-base:x64-windows`
+- For building on macOS, brew utility is needed.
+  - Install all needed packages `brew install cmake python boost boost-python3 qt5`
+  - Do not forget to add qt5 in path as well `echo 'export PATH="/usr/local/opt/qt/bin:$PATH"' >> ~/.bash_profile`
+
+Getting started
+---------------
+
+### nextpnr-ice40
+
+To build the iCE40 version of nextpnr, install [icestorm](http://www.clifford.at/icestorm/) with chipdbs installed in `/usr/local/share/icebox`.
+Then build and install `nextpnr-ice40` using the following commands:
+
+```
+cmake -DARCH=ice40 .
+make -j$(nproc)
+sudo make install
+```
+
+A simple example that runs on the iCEstick dev board can be found in `ice40/blinky.*`.
+Usage example:
+
+```
+cd ice40
+yosys -p 'synth_ice40 -top blinky -json blinky.json' blinky.v               # synthesize into blinky.json
+nextpnr-ice40 --hx1k --json blinky.json --pcf blinky.pcf --asc blinky.asc   # run place and route
+icepack blinky.asc blinky.bin                                               # generate binary bitstream file
+iceprog blinky.bin                                                          # upload design to iCEstick
+```
+
+Running nextpnr in GUI mode:
+
+```
+nextpnr-ice40 --json blinky.json --pcf blinky.pcf --asc blinky.asc --gui
+```
+
+(Use the toolbar buttons or the Python command console to perform actions
+such as pack, place, route, and write output files.)
+
+### nextpnr-ecp5
+
+For ECP5 support, you must download [Project Trellis](https://github.com/SymbiFlow/prjtrellis),
+then follow its instructions to download the latest database and build _libtrellis_.
+
+```
+cmake -DARCH=ecp5 .
+make -j$(nproc)
+sudo make install
+```
+
+ - For an ECP5 blinky, first synthesise using `yosys blinky.ys` in `ecp5/synth`.
+  - Then run ECP5 place-and route using `./nextpnr-ecp5 --json ecp5/synth/blinky.json --basecfg ecp5/synth/ulx3s_empty.config --bit ecp5/synth/ulx3s.bit`
+  - Note that `ulx3s_empty.config` contains fixed/unknown bits to be copied to the output bitstream
+  - You can also use `--textcfg out.config` to write a text file describing the bitstream for debugging
+
+ - More examples of the ECP5 flow for a range of boards can be found in the [Project Trellis Examples](https://github.com/SymbiFlow/prjtrellis/tree/master/examples).
+
+ - Currently the ECP5 flow supports LUTs, flipflops and IO. IO must be instantiated using `TRELLIS_IO` primitives and constraints specified
+   using `LOC` and `IO_TYPE` attributes on those instances, as is used in the examples.
+
+### nextpnr-generic
+
+The generic target allows to run place and route for an arbitrary custom architecture.
+
+```
+cmake -DARCH=generic .
+make -j$(nproc)
+sudo make install
+```
+
+TBD: Getting started example for generic target.
+
+Additional notes for building nextpnr
+-------------------------------------
+
+Use cmake `-D` options to specify which version of nextpnr you want to build.
+
+Use `-DARCH=...` to set the architecture. It is semicolon separated list.
+Use `cmake . -DARCH=all` to build all supported architectures.
+
+The following runs a debug build of the iCE40 architecture without GUI
+and without Python support and only HX1K support:
+
+```
+cmake -DARCH=ice40 -DCMAKE_BUILD_TYPE=Debug -DBUILD_PYTHON=OFF -DBUILD_GUI=OFF -DICE40_HX1K_ONLY=1 .
+make -j$(nproc)
+```
+
+Notes for developers
+--------------------
  
-Building
---------
-
- - Specifying target architecture is mandatory use ARCH parameter to set it. It is semicolon separated list.
-    - Use `cmake . -DARCH=all` to build all supported targets
-    - For example `cmake . -DARCH=ice40` would build just ICE40 support
- - Use CMake to generate the Makefiles (only needs to be done when `CMakeLists.txt` changes)
-    - For an iCE40 debug build, run `cmake -DARCH=ice40 -DCMAKE_BUILD_TYPE=Debug .`
-    - For an iCE40 debug build with HX1K support only, run `cmake -DARCH=ice40 -DCMAKE_BUILD_TYPE=Debug -DICE40_HX1K_ONLY=1 .`
-    - For an iCE40 and ECP5 release build, run `cmake -DARCH="ice40;ecp5" .`
-    - Add `-DCMAKE_INSTALL_PREFIX=/your/install/prefix` to use a different install prefix to the default `/usr/local`
-    - For MSVC build with vcpkg use `-DCMAKE_TOOLCHAIN_FILE=C:/vcpkg/scripts/buildsystems/vcpkg.cmake` using your vcpkg location
-    - For MSVC x64 build adding `-G"Visual Studio 14 2015 Win64"` is needed.
-    - For ECP5 support, you must also specify the path to Project Trellis using `-DTRELLIS_ROOT=/path/trellis`
- - Use Make to run the build itself
-    - For all binary targets, just run `make`
-    - For just the iCE40 CLI&GUI binary, run `make nextpnr-ice40`
-    - To build binary without Python support, use `-DBUILD_PYTHON=OFF`
-    - To build binary without GUI, use `-DBUILD_GUI=OFF`
-    - For minimal binary without Python and GUI, use `-DBUILD_PYTHON=OFF -DBUILD_GUI=OFF`
-    - For just the iCE40 Python module, run `make nextpnrpy_ice40`
-    - Using too many parallel jobs may lead to out-of-memory issues due to the significant memory needed to build the chipdbs
-    - To install nextpnr, run `make install`
+- All code is formatted using `clang-format` according to the style rules in `.clang-format` (LLVM based with 
+  increased indent widths and brace wraps after classes).
+- To automatically format all source code, run `make clangformat`.
+- See the wiki for additional documentation on the architecture API.
 
 Testing
 -------
 
- - To build test binaries as well, use `-DBUILD_TESTS=OFF` and after run `make tests` to run them, or you can run separate binaries.
- - To use code sanitizers use the `cmake` options:
-    - `-DSANITIZE_ADDRESS=ON`
-    - `-DSANITIZE_MEMORY=ON -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++`
-    - `-DSANITIZE_THREAD=ON`
-    - `-DSANITIZE_UNDEFINED=ON`
- - Running valgrind example `valgrind --leak-check=yes --tool=memcheck ./nextpnr-ice40 --json ice40/blinky.json`
+- To build test binaries as well, use `-DBUILD_TESTS=ON` and after `make` run `make tests` to run them, or you can run separate binaries.
+- To use code sanitizers use the `cmake` options:
+  - `-DSANITIZE_ADDRESS=ON`
+  - `-DSANITIZE_MEMORY=ON -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++`
+  - `-DSANITIZE_THREAD=ON`
+  - `-DSANITIZE_UNDEFINED=ON`
+- Running valgrind example `valgrind --leak-check=yes --tool=memcheck ./nextpnr-ice40 --json ice40/blinky.json`
 
-Running
---------
+Links and references
+--------------------
 
- - To run the CLI binary, just run `./nextpnr-ice40` (you should see command line help)
- - To start the UI, run `./nextpnr-ice40 --gui`
- - The Python module is called `nextpnrpy_ice40.so`. To test it, run `PYTHONPATH=. python3 python/python_mod_test.py`
- - Run `yosys blinky.ys` in `ice40/` to synthesise the blinky design and 
-   produce `blinky.json`.
- - To place-and-route the blinky using nextpnr, run `./nextpnr-ice40 --hx1k --json ice40/blinky.json --pcf ice40/blinky.pcf --asc blinky.asc`
+### Synthesis, simulation, and logic optimization
 
- - For an ECP5 blinky, first synthesise using `yosys blinky.ys` in `ecp5/synth`.
- - Then run ECP5 place-and route using
- `./nextpnr-ecp5 --json ecp5/synth/blinky.json --basecfg ecp5/synth/ulx3s_empty.config --bit ecp5/synth/ulx3s.bit`
-    - Note that `ulx3s_empty.config` contains fixed/unknown bits to be copied to the output bitstream
-    - You can also use `--textcfg out.config` to write a text file describing the bitstream for debugging
-  
-Notes
--------
- 
- - All code is formatted using `clang-format` according to the style rules in `.clang-format` (LLVM based with 
- increased indent widths and brace wraps after classes).
- - To automatically format all source code, run `make clangformat`.
+- [Yosys](http://www.clifford.at/yosys/)
+- [Icarus Verilog](http://iverilog.icarus.com/)
+- [ABC](https://people.eecs.berkeley.edu/~alanmi/abc/)
+
+### FPGA bitstream documentation (and tools) projects
+
+- [Project IceStorm (Lattice iCE40)](http://www.clifford.at/icestorm/)
+- [Project Trellis (Lattice ECP5)](https://symbiflow.github.io/prjtrellis-db/)
+- [Project X-Ray (Xilinx 7-Series)](https://symbiflow.github.io/prjxray-db/)
+- [Project Chibi (Intel MAX-V)](https://github.com/rqou/project-chibi)
+
+### Other FOSS place and route tools (FPGA and ASIC)
+
+- [Arachne PNR](https://github.com/cseed/arachne-pnr)
+- [VPR/VTR](https://verilogtorouting.org/)
+- [graywolf/timberwolf](https://github.com/rubund/graywolf)
+- [qrouter](http://opencircuitdesign.com/qrouter/)
diff --git a/common/router1.cc b/common/router1.cc
index e18f27fb..0bd257fd 100644
--- a/common/router1.cc
+++ b/common/router1.cc
@@ -217,7 +217,7 @@ struct Router
                 next_qw.pip = pip;
                 next_qw.delay = next_delay;
                 next_qw.togo = ctx->estimateDelay(next_wire, dst_wire);
-                qw.randtag = ctx->rng();
+                next_qw.randtag = ctx->rng();
 
                 visited[next_qw.wire] = next_qw;
                 queue.push(next_qw);
diff --git a/gui/basewindow.cc b/gui/basewindow.cc
index 6e997011..6d5e97f5 100644
--- a/gui/basewindow.cc
+++ b/gui/basewindow.cc
@@ -86,6 +86,7 @@ BaseMainWindow::BaseMainWindow(std::unique_ptr<Context> context, QWidget *parent
     connect(fpgaView, SIGNAL(clickedBel(BelId, bool)), designview, SLOT(onClickedBel(BelId, bool)));

     connect(fpgaView, SIGNAL(clickedWire(WireId, bool)), designview, SLOT(onClickedWire(WireId, bool)));

     connect(fpgaView, SIGNAL(clickedPip(PipId, bool)), designview, SLOT(onClickedPip(PipId, bool)));

+    connect(designview, SIGNAL(zoomSelected()), fpgaView, SLOT(zoomSelected()));

 

     connect(designview, SIGNAL(highlight(std::vector<DecalXY>, int)), fpgaView,

             SLOT(onHighlightGroupChanged(std::vector<DecalXY>, int)));

diff --git a/gui/designwidget.cc b/gui/designwidget.cc
index d55c84e9..5107fbee 100644
--- a/gui/designwidget.cc
+++ b/gui/designwidget.cc
@@ -30,48 +30,14 @@
 

 NEXTPNR_NAMESPACE_BEGIN

 

-class ElementTreeItem : public QTreeWidgetItem

+DesignWidget::DesignWidget(QWidget *parent) : QWidget(parent), ctx(nullptr), selectionModel(nullptr)

 {

-  public:

-    ElementTreeItem(ElementType t, QString str, QTreeWidgetItem *parent)

-            : QTreeWidgetItem(parent, QStringList(str)), type(t)

-    {

-        this->setFlags(this->flags() & ~Qt::ItemIsSelectable);

-    }

-    virtual ~ElementTreeItem(){};

-

-    ElementType getType() { return type; };

-

-  private:

-    ElementType type;

-};

-

-class IdStringTreeItem : public ElementTreeItem

-{

-  public:

-    IdStringTreeItem(IdString d, ElementType t, QString str, QTreeWidgetItem *parent) : ElementTreeItem(t, str, parent)

-    {

-        this->setFlags(this->flags() | Qt::ItemIsSelectable);

-        this->data = d;

-    }

-    virtual ~IdStringTreeItem(){};

-

-    IdString getData() { return this->data; };

-

-  private:

-    IdString data;

-};

-

-DesignWidget::DesignWidget(QWidget *parent) : QWidget(parent), ctx(nullptr), nets_root(nullptr), cells_root(nullptr)

-{

-

-    treeWidget = new QTreeWidget();

-

     // Add tree view

-    treeWidget->setColumnCount(1);

-    treeWidget->setHeaderLabel("Items");

-    treeWidget->setContextMenuPolicy(Qt::CustomContextMenu);

-    treeWidget->setSelectionMode(QAbstractItemView::ExtendedSelection);

+    treeView = new QTreeView();

+    treeModel = new ContextTreeModel();

+    treeView->setModel(treeModel);

+    treeView->setContextMenuPolicy(Qt::CustomContextMenu);

+    treeView->setSelectionMode(QAbstractItemView::ExtendedSelection);

 

     // Add property view

     variantManager = new QtVariantPropertyManager(this);

@@ -96,7 +62,7 @@ DesignWidget::DesignWidget(QWidget *parent) : QWidget(parent), ctx(nullptr), net
     connect(actionFirst, &QAction::triggered, this, [this] {

         history_ignore = true;

         history_index = 0;

-        treeWidget->setCurrentItem(history.at(history_index));

+        selectionModel->setCurrentIndex(history.at(history_index), QItemSelectionModel::ClearAndSelect);

         updateButtons();

     });

 

@@ -106,7 +72,7 @@ DesignWidget::DesignWidget(QWidget *parent) : QWidget(parent), ctx(nullptr), net
     connect(actionPrev, &QAction::triggered, this, [this] {

         history_ignore = true;

         history_index--;

-        treeWidget->setCurrentItem(history.at(history_index));

+        selectionModel->setCurrentIndex(history.at(history_index), QItemSelectionModel::ClearAndSelect);

         updateButtons();

     });

 

@@ -116,7 +82,7 @@ DesignWidget::DesignWidget(QWidget *parent) : QWidget(parent), ctx(nullptr), net
     connect(actionNext, &QAction::triggered, this, [this] {

         history_ignore = true;

         history_index++;

-        treeWidget->setCurrentItem(history.at(history_index));

+        selectionModel->setCurrentIndex(history.at(history_index), QItemSelectionModel::ClearAndSelect);

         updateButtons();

     });

 

@@ -126,7 +92,7 @@ DesignWidget::DesignWidget(QWidget *parent) : QWidget(parent), ctx(nullptr), net
     connect(actionLast, &QAction::triggered, this, [this] {

         history_ignore = true;

         history_index = int(history.size() - 1);

-        treeWidget->setCurrentItem(history.at(history_index));

+        selectionModel->setCurrentIndex(history.at(history_index), QItemSelectionModel::ClearAndSelect);

         updateButtons();

     });

 

@@ -136,11 +102,11 @@ DesignWidget::DesignWidget(QWidget *parent) : QWidget(parent), ctx(nullptr), net
     connect(actionClear, &QAction::triggered, this, [this] {

         history_index = -1;

         history.clear();

-        QTreeWidgetItem *clickItem = treeWidget->selectedItems().at(0);

-        if (clickItem->parent()) {

-            ElementType type = static_cast<ElementTreeItem *>(clickItem)->getType();

+        QModelIndex index = selectionModel->selectedIndexes().at(0);

+        if (index.isValid()) {

+            ElementType type = treeModel->nodeFromIndex(index)->type();

             if (type != ElementType::NONE)

-                addToHistory(treeWidget->selectedItems().at(0));

+                addToHistory(index);

         }

         updateButtons();

     });

@@ -158,7 +124,7 @@ DesignWidget::DesignWidget(QWidget *parent) : QWidget(parent), ctx(nullptr), net
     vbox1->setSpacing(5);

     vbox1->setContentsMargins(0, 0, 0, 0);

     vbox1->addWidget(lineEdit);

-    vbox1->addWidget(treeWidget);

+    vbox1->addWidget(treeView);

 

     QWidget *toolbarWidget = new QWidget();

     QHBoxLayout *hbox = new QHBoxLayout;

@@ -192,8 +158,11 @@ DesignWidget::DesignWidget(QWidget *parent) : QWidget(parent), ctx(nullptr), net
             &DesignWidget::prepareMenuProperty);

     connect(propertyEditor->treeWidget(), &QTreeWidget::itemDoubleClicked, this, &DesignWidget::onItemDoubleClicked);

 

-    connect(treeWidget, SIGNAL(itemSelectionChanged()), SLOT(onItemSelectionChanged()));

-    connect(treeWidget, &QTreeWidget::customContextMenuRequested, this, &DesignWidget::prepareMenuTree);

+    connect(treeView, &QTreeView::customContextMenuRequested, this, &DesignWidget::prepareMenuTree);

+    connect(treeView, &QTreeView::doubleClicked, this, &DesignWidget::onDoubleClicked);

+    selectionModel = treeView->selectionModel();

+    connect(selectionModel, SIGNAL(selectionChanged(const QItemSelection &, const QItemSelection &)),

+            SLOT(onSelectionChanged(const QItemSelection &, const QItemSelection &)));

 

     history_index = -1;

     history_ignore = false;

@@ -219,7 +188,7 @@ void DesignWidget::updateButtons()
     actionLast->setEnabled(history_index < (count - 1));

 }

 

-void DesignWidget::addToHistory(QTreeWidgetItem *item)

+void DesignWidget::addToHistory(QModelIndex item)

 {

     if (!history_ignore) {

         int count = int(history.size());

@@ -234,194 +203,38 @@ void DesignWidget::addToHistory(QTreeWidgetItem *item)
 

 void DesignWidget::newContext(Context *ctx)

 {

+    if (!ctx)

+        return;

+

     highlightSelected.clear();

-    treeWidget->clear();

-    // reset pointers since they are not valid after clear

-    nets_root = nullptr;

-    cells_root = nullptr;

     history_ignore = false;

     history_index = -1;

     history.clear();

     updateButtons();

 

-    for (int i = 0; i < 6; i++)

-        nameToItem[i].clear();

-

+    highlightSelected.clear();

     this->ctx = ctx;

-

-    // Add bels to tree

-    QTreeWidgetItem *bel_root = new QTreeWidgetItem(treeWidget);

-    QMap<QString, QTreeWidgetItem *> bel_items;

-    bel_root->setText(0, "Bels");

-    bel_root->setFlags(bel_root->flags() & ~Qt::ItemIsSelectable);

-    treeWidget->insertTopLevelItem(0, bel_root);

-    if (ctx) {

-        for (auto bel : ctx->getBels()) {

-            auto id = ctx->getBelName(bel);

-            QStringList items = QString(id.c_str(ctx)).split("/");

-            QString name;

-            QTreeWidgetItem *parent = nullptr;

-            for (int i = 0; i < items.size(); i++) {

-                if (!name.isEmpty())

-                    name += "/";

-                name += items.at(i);

-                if (!bel_items.contains(name)) {

-                    if (i == items.size() - 1)

-                        nameToItem[0].insert(name, new IdStringTreeItem(id, ElementType::BEL, items.at(i), parent));

-                    else

-                        bel_items.insert(name, new ElementTreeItem(ElementType::NONE, items.at(i), parent));

-                }

-                parent = bel_items[name];

-            }

-        }

-    }

-    for (auto bel : bel_items.toStdMap()) {

-        bel_root->addChild(bel.second);

-    }

-    for (auto bel : nameToItem[0].toStdMap()) {

-        bel_root->addChild(bel.second);

-    }

-

-    // Add wires to tree

-    QTreeWidgetItem *wire_root = new QTreeWidgetItem(treeWidget);

-    QMap<QString, QTreeWidgetItem *> wire_items;

-    wire_root->setText(0, "Wires");

-    wire_root->setFlags(wire_root->flags() & ~Qt::ItemIsSelectable);

-    treeWidget->insertTopLevelItem(0, wire_root);

-    if (ctx) {

-        for (auto wire : ctx->getWires()) {

-            auto id = ctx->getWireName(wire);

-            QStringList items = QString(id.c_str(ctx)).split("/");

-            QString name;

-            QTreeWidgetItem *parent = nullptr;

-            for (int i = 0; i < items.size(); i++) {

-                if (!name.isEmpty())

-                    name += "/";

-                name += items.at(i);

-                if (!wire_items.contains(name)) {

-                    if (i == items.size() - 1)

-                        nameToItem[1].insert(name, new IdStringTreeItem(id, ElementType::WIRE, items.at(i), parent));

-                    else

-                        wire_items.insert(name, new ElementTreeItem(ElementType::NONE, items.at(i), parent));

-                }

-                parent = wire_items[name];

-            }

-        }

-    }

-    for (auto wire : wire_items.toStdMap()) {

-        wire_root->addChild(wire.second);

-    }

-    for (auto wire : nameToItem[1].toStdMap()) {

-        wire_root->addChild(wire.second);

-    }

-    // Add pips to tree

-    QTreeWidgetItem *pip_root = new QTreeWidgetItem(treeWidget);

-    QMap<QString, QTreeWidgetItem *> pip_items;

-    pip_root->setText(0, "Pips");

-    pip_root->setFlags(pip_root->flags() & ~Qt::ItemIsSelectable);

-    treeWidget->insertTopLevelItem(0, pip_root);

-#ifndef ARCH_ECP5

-    if (ctx) {

-        for (auto pip : ctx->getPips()) {

-            auto id = ctx->getPipName(pip);

-            QStringList items = QString(id.c_str(ctx)).split("/");

-            QString name;

-            QTreeWidgetItem *parent = nullptr;

-            for (int i = 0; i < items.size(); i++) {

-                if (!name.isEmpty())

-                    name += "/";

-                name += items.at(i);

-                if (!pip_items.contains(name)) {

-                    if (i == items.size() - 1)

-                        nameToItem[2].insert(name, new IdStringTreeItem(id, ElementType::PIP, items.at(i), parent));

-                    else

-                        pip_items.insert(name, new ElementTreeItem(ElementType::NONE, items.at(i), parent));

-                }

-                parent = pip_items[name];

-            }

-        }

-    }

-    for (auto pip : pip_items.toStdMap()) {

-        pip_root->addChild(pip.second);

-    }

-    for (auto pip : nameToItem[2].toStdMap()) {

-        pip_root->addChild(pip.second);

-    }

-#endif

-

-    nets_root = new QTreeWidgetItem(treeWidget);

-    nets_root->setText(0, "Nets");

-    nets_root->setFlags(nets_root->flags() & ~Qt::ItemIsSelectable);

-    treeWidget->insertTopLevelItem(0, nets_root);

-

-    cells_root = new QTreeWidgetItem(treeWidget);

-    cells_root->setText(0, "Cells");

-    cells_root->setFlags(cells_root->flags() & ~Qt::ItemIsSelectable);

-    treeWidget->insertTopLevelItem(0, cells_root);

-

+    treeModel->loadData(ctx);

     updateTree();

 }

 

 void DesignWidget::updateTree()

 {

-    if (!ctx)

-        return;

-

     clearProperties();

 

-    // treeWidget->setSortingEnabled(false);

-

-    // Remove nets not existing any more

-    QMap<QString, QTreeWidgetItem *>::iterator i = nameToItem[3].begin();

-    while (i != nameToItem[3].end()) {

-        QMap<QString, QTreeWidgetItem *>::iterator prev = i;

+    QMap<ContextTreeItem *, int>::iterator i = highlightSelected.begin();

+    while (i != highlightSelected.end()) {

+        QMap<ContextTreeItem *, int>::iterator prev = i;

         ++i;

-        if (ctx->nets.find(ctx->id(prev.key().toStdString())) == ctx->nets.end()) {

-            if (treeWidget->currentItem() == prev.value())

-                treeWidget->setCurrentItem(nets_root);

-            if (highlightSelected.contains(prev.value()))

-                highlightSelected.remove(prev.value());

-            delete prev.value();

-            nameToItem[3].erase(prev);

+        if (prev.key()->type() == ElementType::NET && ctx->nets.find(prev.key()->id()) == ctx->nets.end()) {

+            highlightSelected.erase(prev);

         }

-    }

-    // Add nets to tree

-    for (auto &item : ctx->nets) {

-        auto id = item.first;

-        QString name = QString(id.c_str(ctx));

-        if (!nameToItem[3].contains(name)) {

-            IdStringTreeItem *newItem = new IdStringTreeItem(id, ElementType::NET, name, nullptr);

-            nets_root->addChild(newItem);

-            nameToItem[3].insert(name, newItem);

+        if (prev.key()->type() == ElementType::CELL && ctx->cells.find(prev.key()->id()) == ctx->cells.end()) {

+            highlightSelected.erase(prev);

         }

     }

 

-    // Remove cells not existing any more

-    i = nameToItem[4].begin();

-    while (i != nameToItem[4].end()) {

-        QMap<QString, QTreeWidgetItem *>::iterator prev = i;

-        ++i;

-        if (ctx->cells.find(ctx->id(prev.key().toStdString())) == ctx->cells.end()) {

-            if (treeWidget->currentItem() == prev.value())

-                treeWidget->setCurrentItem(cells_root);

-            if (highlightSelected.contains(prev.value()))

-                highlightSelected.remove(prev.value());

-            delete prev.value();

-            nameToItem[4].erase(prev);

-        }

-    }

-    // Add cells to tree

-    for (auto &item : ctx->cells) {

-        auto id = item.first;

-        QString name = QString(id.c_str(ctx));

-        if (!nameToItem[4].contains(name)) {

-            IdStringTreeItem *newItem = new IdStringTreeItem(id, ElementType::CELL, name, nullptr);

-            cells_root->addChild(newItem);

-            nameToItem[4].insert(name, newItem);

-        }

-    }

-    // treeWidget->sortByColumn(0, Qt::AscendingOrder);

-    // treeWidget->setSortingEnabled(true);

+    treeModel->updateData(ctx);

 }

 QtProperty *DesignWidget::addTopLevelProperty(const QString &id)

 {

@@ -460,21 +273,6 @@ QString DesignWidget::getElementTypeName(ElementType type)
         return "CELL";

     return "";

 }

-int DesignWidget::getElementIndex(ElementType type)

-{

-    if (type == ElementType::BEL)

-        return 0;

-    if (type == ElementType::WIRE)

-        return 1;

-    if (type == ElementType::PIP)

-        return 2;

-    if (type == ElementType::NET)

-        return 3;

-    if (type == ElementType::CELL)

-        return 4;

-    return -1;

-}

-

 ElementType DesignWidget::getElementTypeByName(QString type)

 {

     if (type == "BEL")

@@ -510,59 +308,58 @@ QtProperty *DesignWidget::addSubGroup(QtProperty *topItem, const QString &name)
 

 void DesignWidget::onClickedBel(BelId bel, bool keep)

 {

-    QTreeWidgetItem *item = nameToItem[getElementIndex(ElementType::BEL)].value(ctx->getBelName(bel).c_str(ctx));

-    treeWidget->setCurrentItem(item);

+    ContextTreeItem *item = treeModel->nodeForIdType(ElementType::BEL, ctx->getBelName(bel).c_str(ctx));

+    selectionModel->setCurrentIndex(treeModel->indexFromNode(item),

+                                    keep ? QItemSelectionModel::Select : QItemSelectionModel::ClearAndSelect);

     Q_EMIT selected(getDecals(ElementType::BEL, ctx->getBelName(bel)), keep);

 }

 

 void DesignWidget::onClickedWire(WireId wire, bool keep)

 {

-    QTreeWidgetItem *item = nameToItem[getElementIndex(ElementType::WIRE)].value(ctx->getWireName(wire).c_str(ctx));

-    treeWidget->setCurrentItem(item);

+    ContextTreeItem *item = treeModel->nodeForIdType(ElementType::WIRE, ctx->getWireName(wire).c_str(ctx));

+    selectionModel->setCurrentIndex(treeModel->indexFromNode(item),

+                                    keep ? QItemSelectionModel::Select : QItemSelectionModel::ClearAndSelect);

     Q_EMIT selected(getDecals(ElementType::WIRE, ctx->getWireName(wire)), keep);

 }

 

 void DesignWidget::onClickedPip(PipId pip, bool keep)

 {

-    QTreeWidgetItem *item = nameToItem[getElementIndex(ElementType::PIP)].value(ctx->getPipName(pip).c_str(ctx));

-    treeWidget->setCurrentItem(item);

+    ContextTreeItem *item = treeModel->nodeForIdType(ElementType::PIP, ctx->getPipName(pip).c_str(ctx));

+    selectionModel->setCurrentIndex(treeModel->indexFromNode(item),

+                                    keep ? QItemSelectionModel::Select : QItemSelectionModel::ClearAndSelect);

     Q_EMIT selected(getDecals(ElementType::PIP, ctx->getPipName(pip)), keep);

 }

 

-void DesignWidget::onItemSelectionChanged()

+void DesignWidget::onSelectionChanged(const QItemSelection &, const QItemSelection &)

 {

-    if (treeWidget->selectedItems().size() == 0)

+    if (selectionModel->selectedIndexes().size() == 0)

         return;

 

-    if (treeWidget->selectedItems().size() > 1) {

+    if (selectionModel->selectedIndexes().size() > 1) {

         std::vector<DecalXY> decals;

-        for (auto clickItem : treeWidget->selectedItems()) {

-            IdString value = static_cast<IdStringTreeItem *>(clickItem)->getData();

-            ElementType type = static_cast<ElementTreeItem *>(clickItem)->getType();

-            std::vector<DecalXY> d = getDecals(type, value);

+        for (auto index : selectionModel->selectedIndexes()) {

+            ContextTreeItem *item = treeModel->nodeFromIndex(index);

+            std::vector<DecalXY> d = getDecals(item->type(), item->id());

             std::move(d.begin(), d.end(), std::back_inserter(decals));

         }

         Q_EMIT selected(decals, false);

         return;

     }

-

-    QTreeWidgetItem *clickItem = treeWidget->selectedItems().at(0);

-

-    if (!clickItem->parent())

+    QModelIndex index = selectionModel->selectedIndexes().at(0);

+    if (!index.isValid())

         return;

+    ContextTreeItem *clickItem = treeModel->nodeFromIndex(index);

 

-    ElementType type = static_cast<ElementTreeItem *>(clickItem)->getType();

-    if (type == ElementType::NONE) {

+    ElementType type = clickItem->type();

+    if (type == ElementType::NONE)

         return;

-    }

-

     std::vector<DecalXY> decals;

 

-    addToHistory(clickItem);

+    addToHistory(index);

 

     clearProperties();

 

-    IdString c = static_cast<IdStringTreeItem *>(clickItem)->getData();

+    IdString c = clickItem->id();

     Q_EMIT selected(getDecals(type, c), false);

 

     if (type == ElementType::BEL) {

@@ -799,7 +596,7 @@ std::vector<DecalXY> DesignWidget::getDecals(ElementType type, IdString value)
     return decals;

 }

 

-void DesignWidget::updateHighlightGroup(QList<QTreeWidgetItem *> items, int group)

+void DesignWidget::updateHighlightGroup(QList<ContextTreeItem *> items, int group)

 {

     const bool shouldClear = items.size() == 1;

     for (auto item : items) {

@@ -814,9 +611,7 @@ void DesignWidget::updateHighlightGroup(QList<QTreeWidgetItem *> items, int grou
     std::vector<DecalXY> decals[8];

 

     for (auto it : highlightSelected.toStdMap()) {

-        ElementType type = static_cast<ElementTreeItem *>(it.first)->getType();

-        IdString value = static_cast<IdStringTreeItem *>(it.first)->getData();

-        std::vector<DecalXY> d = getDecals(type, value);

+        std::vector<DecalXY> d = getDecals(it.first->type(), it.first->id());

         std::move(d.begin(), d.end(), std::back_inserter(decals[it.second]));

     }

     for (int i = 0; i < 8; i++)

@@ -826,7 +621,7 @@ void DesignWidget::updateHighlightGroup(QList<QTreeWidgetItem *> items, int grou
 void DesignWidget::prepareMenuProperty(const QPoint &pos)

 {

     QTreeWidget *tree = propertyEditor->treeWidget();

-    QList<QTreeWidgetItem *> items;

+    QList<ContextTreeItem *> items;

     for (auto itemContextMenu : tree->selectedItems()) {

         QtBrowserItem *browserItem = propertyEditor->itemToBrowserItem(itemContextMenu);

         if (!browserItem)

@@ -836,11 +631,11 @@ void DesignWidget::prepareMenuProperty(const QPoint &pos)
         if (type == ElementType::NONE)

             continue;

         IdString value = ctx->id(selectedProperty->valueText().toStdString());

-        items.append(nameToItem[getElementIndex(type)].value(value.c_str(ctx)));

+        items.append(treeModel->nodeForIdType(type, value.c_str(ctx)));

     }

     int selectedIndex = -1;

     if (items.size() == 1) {

-        QTreeWidgetItem *item = items.at(0);

+        ContextTreeItem *item = items.at(0);

         if (highlightSelected.contains(item))

             selectedIndex = highlightSelected[item];

     }

@@ -850,9 +645,7 @@ void DesignWidget::prepareMenuProperty(const QPoint &pos)
     connect(selectAction, &QAction::triggered, this, [this, items] {

         std::vector<DecalXY> decals;

         for (auto clickItem : items) {

-            IdString value = static_cast<IdStringTreeItem *>(clickItem)->getData();

-            ElementType type = static_cast<ElementTreeItem *>(clickItem)->getType();

-            std::vector<DecalXY> d = getDecals(type, value);

+            std::vector<DecalXY> d = getDecals(clickItem->type(), clickItem->id());

             std::move(d.begin(), d.end(), std::back_inserter(decals));

         }

         Q_EMIT selected(decals, false);

@@ -878,12 +671,18 @@ void DesignWidget::prepareMenuProperty(const QPoint &pos)
 

 void DesignWidget::prepareMenuTree(const QPoint &pos)

 {

-    if (treeWidget->selectedItems().size() == 0)

-        return;

     int selectedIndex = -1;

-    QList<QTreeWidgetItem *> items = treeWidget->selectedItems();

-    if (treeWidget->selectedItems().size() == 1) {

-        QTreeWidgetItem *item = treeWidget->selectedItems().at(0);

+

+    if (selectionModel->selectedIndexes().size() == 0)

+        return;

+

+    QList<ContextTreeItem *> items;

+    for (auto index : selectionModel->selectedIndexes()) {

+        ContextTreeItem *item = treeModel->nodeFromIndex(index);

+        items.append(item);

+    }

+    if (items.size() == 1) {

+        ContextTreeItem *item = items.at(0);

         if (highlightSelected.contains(item))

             selectedIndex = highlightSelected[item];

     }

@@ -902,17 +701,17 @@ void DesignWidget::prepareMenuTree(const QPoint &pos)
             action->setChecked(true);

         connect(action, &QAction::triggered, this, [this, i, items] { updateHighlightGroup(items, i); });

     }

-    menu.exec(treeWidget->mapToGlobal(pos));

+    menu.exec(treeView->mapToGlobal(pos));

 }

 

 void DesignWidget::onItemDoubleClicked(QTreeWidgetItem *item, int column)

 {

     QtProperty *selectedProperty = propertyEditor->itemToBrowserItem(item)->property();

     ElementType type = getElementTypeByName(selectedProperty->propertyId());

-    QString value = selectedProperty->valueText();

-    int index = getElementIndex(type);

-    if (type != ElementType::NONE && nameToItem[index].contains(value))

-        treeWidget->setCurrentItem(nameToItem[index].value(value));

+    ContextTreeItem *it = treeModel->nodeForIdType(type, selectedProperty->valueText());

+    if (it)

+        selectionModel->setCurrentIndex(treeModel->indexFromNode(it), QItemSelectionModel::ClearAndSelect);

 }

 

+void DesignWidget::onDoubleClicked(const QModelIndex &index) { Q_EMIT zoomSelected(); }

 NEXTPNR_NAMESPACE_END

diff --git a/gui/designwidget.h b/gui/designwidget.h
index 60291cf3..27ead589 100644
--- a/gui/designwidget.h
+++ b/gui/designwidget.h
@@ -20,27 +20,17 @@
 #ifndef DESIGNWIDGET_H

 #define DESIGNWIDGET_H

 

-#include <QTreeWidget>

+#include <QTreeView>

 #include <QVariant>

 #include "nextpnr.h"

 #include "qtgroupboxpropertybrowser.h"

 #include "qtpropertymanager.h"

 #include "qttreepropertybrowser.h"

 #include "qtvariantproperty.h"

+#include "treemodel.h"

 

 NEXTPNR_NAMESPACE_BEGIN

 

-enum class ElementType

-{

-    NONE,

-    BEL,

-    WIRE,

-    PIP,

-    NET,

-    CELL,

-    GROUP

-};

-

 class DesignWidget : public QWidget

 {

     Q_OBJECT

@@ -59,19 +49,21 @@ class DesignWidget : public QWidget
     ElementType getElementTypeByName(QString type);

     int getElementIndex(ElementType type);

     void updateButtons();

-    void addToHistory(QTreeWidgetItem *item);

+    void addToHistory(QModelIndex item);

     std::vector<DecalXY> getDecals(ElementType type, IdString value);

-    void updateHighlightGroup(QList<QTreeWidgetItem *> item, int group);

+    void updateHighlightGroup(QList<ContextTreeItem *> item, int group);

   Q_SIGNALS:

     void info(std::string text);

     void selected(std::vector<DecalXY> decal, bool keep);

     void highlight(std::vector<DecalXY> decal, int group);

+    void zoomSelected();

 

   private Q_SLOTS:

     void prepareMenuProperty(const QPoint &pos);

     void prepareMenuTree(const QPoint &pos);

-    void onItemSelectionChanged();

+    void onSelectionChanged(const QItemSelection &selected, const QItemSelection &deselected);

     void onItemDoubleClicked(QTreeWidgetItem *item, int column);

+    void onDoubleClicked(const QModelIndex &index);

   public Q_SLOTS:

     void newContext(Context *ctx);

     void updateTree();

@@ -82,8 +74,9 @@ class DesignWidget : public QWidget
   private:

     Context *ctx;

 

-    QTreeWidget *treeWidget;

-

+    QTreeView *treeView;

+    QItemSelectionModel *selectionModel;

+    ContextTreeModel *treeModel;

     QtVariantPropertyManager *variantManager;

     QtVariantPropertyManager *readOnlyManager;

     QtGroupPropertyManager *groupManager;

@@ -93,14 +86,10 @@ class DesignWidget : public QWidget
     QMap<QtProperty *, QString> propertyToId;

     QMap<QString, QtProperty *> idToProperty;

 

-    QMap<QString, QTreeWidgetItem *> nameToItem[6];

-    std::vector<QTreeWidgetItem *> history;

+    std::vector<QModelIndex> history;

     int history_index;

     bool history_ignore;

 

-    QTreeWidgetItem *nets_root;

-    QTreeWidgetItem *cells_root;

-

     QAction *actionFirst;

     QAction *actionPrev;

     QAction *actionNext;

@@ -108,7 +97,7 @@ class DesignWidget : public QWidget
     QAction *actionClear;

 

     QColor highlightColors[8];

-    QMap<QTreeWidgetItem *, int> highlightSelected;

+    QMap<ContextTreeItem *, int> highlightSelected;

 };

 

 NEXTPNR_NAMESPACE_END

diff --git a/gui/treemodel.cc b/gui/treemodel.cc
new file mode 100644
index 00000000..59391f02
--- /dev/null
+++ b/gui/treemodel.cc
@@ -0,0 +1,329 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Miodrag Milanovic <miodrag@symbioticeda.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "treemodel.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+static bool contextTreeItemLessThan(const ContextTreeItem *v1, const ContextTreeItem *v2)
+ {
+     return v1->name() < v2->name();
+ }
+
+ContextTreeItem::ContextTreeItem() { parentNode = nullptr; }
+
+ContextTreeItem::ContextTreeItem(QString name)
+        : parentNode(nullptr), itemId(IdString()), itemType(ElementType::NONE), itemName(name)
+{
+}
+
+ContextTreeItem::ContextTreeItem(IdString id, ElementType type, QString name)
+        : parentNode(nullptr), itemId(id), itemType(type), itemName(name)
+{
+}
+
+ContextTreeItem::~ContextTreeItem()
+{
+    if (parentNode)
+        parentNode->children.removeOne(this);
+    qDeleteAll(children);
+}
+void ContextTreeItem::addChild(ContextTreeItem *item)
+{
+    item->parentNode = this;
+    children.append(item);
+}
+
+void ContextTreeItem::sort()
+{
+    for (auto item : children)
+        if (item->count()>1) item->sort();
+    qSort(children.begin(), children.end(), contextTreeItemLessThan);
+}
+
+ContextTreeModel::ContextTreeModel(QObject *parent) : QAbstractItemModel(parent) { root = new ContextTreeItem(); }
+
+ContextTreeModel::~ContextTreeModel() { delete root; }
+
+void ContextTreeModel::loadData(Context *ctx)
+{
+    if (!ctx)
+        return;
+
+    beginResetModel();
+
+    delete root;
+    root = new ContextTreeItem();
+
+    for (int i = 0; i < 6; i++)
+        nameToItem[i].clear();
+
+    IdString none;
+
+    ContextTreeItem *bels_root = new ContextTreeItem("Bels");
+    root->addChild(bels_root);
+    QMap<QString, ContextTreeItem *> bel_items;
+
+    // Add bels to tree
+    for (auto bel : ctx->getBels()) {
+        IdString id = ctx->getBelName(bel);
+        QStringList items = QString(id.c_str(ctx)).split("/");
+        QString name;
+        ContextTreeItem *parent = bels_root;
+        for (int i = 0; i < items.size(); i++) {
+            if (!name.isEmpty())
+                name += "/";
+            name += items.at(i);
+            if (!bel_items.contains(name)) {
+                if (i == items.size() - 1) {
+                    ContextTreeItem *item = new ContextTreeItem(id, ElementType::BEL, items.at(i));
+                    parent->addChild(item);
+                    nameToItem[0].insert(name, item);
+                } else {
+                    ContextTreeItem *item = new ContextTreeItem(none, ElementType::NONE, items.at(i));
+                    parent->addChild(item);
+                    bel_items.insert(name, item);
+                }
+            }
+            parent = bel_items[name];
+        }
+    }    
+    bels_root->sort();
+    
+    ContextTreeItem *wire_root = new ContextTreeItem("Wires");
+    root->addChild(wire_root);
+    QMap<QString, ContextTreeItem *> wire_items;
+
+    // Add wires to tree
+    for (auto wire : ctx->getWires()) {
+        auto id = ctx->getWireName(wire);
+        QStringList items = QString(id.c_str(ctx)).split("/");
+        QString name;
+        ContextTreeItem *parent = wire_root;
+        for (int i = 0; i < items.size(); i++) {
+            if (!name.isEmpty())
+                name += "/";
+            name += items.at(i);
+            if (!wire_items.contains(name)) {
+                if (i == items.size() - 1) {
+                    ContextTreeItem *item = new ContextTreeItem(id, ElementType::WIRE, items.at(i));
+                    parent->addChild(item);
+                    nameToItem[1].insert(name, item);
+                } else {
+                    ContextTreeItem *item = new ContextTreeItem(none, ElementType::NONE, items.at(i));
+                    parent->addChild(item);
+                    wire_items.insert(name, item);
+                }
+            }
+            parent = wire_items[name];
+        }
+    }
+    wire_root->sort();
+
+    ContextTreeItem *pip_root = new ContextTreeItem("Pips");
+    root->addChild(pip_root);
+    QMap<QString, ContextTreeItem *> pip_items;
+
+    // Add pips to tree
+    for (auto pip : ctx->getPips()) {
+        auto id = ctx->getPipName(pip);
+        QStringList items = QString(id.c_str(ctx)).split("/");
+        QString name;
+        ContextTreeItem *parent = pip_root;
+        for (int i = 0; i < items.size(); i++) {
+            if (!name.isEmpty())
+                name += "/";
+            name += items.at(i);
+            if (!pip_items.contains(name)) {
+                if (i == items.size() - 1) {
+                    ContextTreeItem *item = new ContextTreeItem(id, ElementType::PIP, items.at(i));
+                    parent->addChild(item);
+                    nameToItem[2].insert(name, item);
+                } else {
+                    ContextTreeItem *item = new ContextTreeItem(none, ElementType::NONE, items.at(i));
+                    parent->addChild(item);
+                    pip_items.insert(name, item);
+                }
+            }
+            parent = pip_items[name];
+        }
+    }
+    pip_root->sort();
+
+    nets_root = new ContextTreeItem("Nets");
+    root->addChild(nets_root);
+
+    cells_root = new ContextTreeItem("Cells");
+    root->addChild(cells_root);
+
+    endResetModel();
+}
+
+void ContextTreeModel::updateData(Context *ctx)
+{
+    if (!ctx)
+        return;
+
+    beginResetModel();
+
+    //QModelIndex nets_index = indexFromNode(nets_root);
+    // Remove nets not existing any more
+    QMap<QString, ContextTreeItem *>::iterator i = nameToItem[3].begin();
+    while (i != nameToItem[3].end()) {
+        QMap<QString, ContextTreeItem *>::iterator prev = i;
+        ++i;
+        if (ctx->nets.find(ctx->id(prev.key().toStdString())) == ctx->nets.end()) {
+            //int pos = prev.value()->parent()->indexOf(prev.value());
+            //beginRemoveRows(nets_index, pos, pos);
+            delete prev.value();
+            nameToItem[3].erase(prev);
+            //endRemoveRows();
+        }
+    }
+    // Add nets to tree
+    for (auto &item : ctx->nets) {
+        auto id = item.first;
+        QString name = QString(id.c_str(ctx));
+        if (!nameToItem[3].contains(name)) {
+            //beginInsertRows(nets_index, nets_root->count() + 1, nets_root->count() + 1);
+            ContextTreeItem *newItem = new ContextTreeItem(id, ElementType::NET, name);
+            nets_root->addChild(newItem);
+            nameToItem[3].insert(name, newItem);
+            //endInsertRows();
+        }
+    }
+
+    nets_root->sort();
+
+    //QModelIndex cell_index = indexFromNode(cells_root);
+    // Remove cells not existing any more
+    i = nameToItem[4].begin();
+    while (i != nameToItem[4].end()) {
+        QMap<QString, ContextTreeItem *>::iterator prev = i;
+        ++i;
+        if (ctx->cells.find(ctx->id(prev.key().toStdString())) == ctx->cells.end()) {
+            //int pos = prev.value()->parent()->indexOf(prev.value());
+            //beginRemoveRows(cell_index, pos, pos);
+            delete prev.value();
+            nameToItem[4].erase(prev);
+            //endRemoveRows();
+        }
+    }
+    // Add cells to tree
+    for (auto &item : ctx->cells) {
+        auto id = item.first;
+        QString name = QString(id.c_str(ctx));
+        if (!nameToItem[4].contains(name)) {
+            //beginInsertRows(cell_index, cells_root->count() + 1, cells_root->count() + 1);
+            ContextTreeItem *newItem = new ContextTreeItem(id, ElementType::CELL, name);
+            cells_root->addChild(newItem);
+            nameToItem[4].insert(name, newItem);
+            //endInsertRows();
+        }
+    }
+
+    cells_root->sort();
+
+    endResetModel();
+}
+
+int ContextTreeModel::rowCount(const QModelIndex &parent) const { return nodeFromIndex(parent)->count(); }
+
+int ContextTreeModel::columnCount(const QModelIndex &parent) const { return 1; }
+
+QModelIndex ContextTreeModel::index(int row, int column, const QModelIndex &parent) const
+{
+    ContextTreeItem *node = nodeFromIndex(parent);
+    if (row >= node->count())
+        return QModelIndex();
+    return createIndex(row, column, node->at(row));
+}
+
+QModelIndex ContextTreeModel::parent(const QModelIndex &child) const
+{
+    ContextTreeItem *parent = nodeFromIndex(child)->parent();
+    if (parent == root)
+        return QModelIndex();
+    ContextTreeItem *node = parent->parent();
+    return createIndex(node->indexOf(parent), 0, parent);
+}
+
+QVariant ContextTreeModel::data(const QModelIndex &index, int role) const
+{
+    if (index.column() != 0)
+        return QVariant();
+    if (role != Qt::DisplayRole)
+        return QVariant();
+    ContextTreeItem *node = nodeFromIndex(index);
+    return node->name();
+}
+
+QVariant ContextTreeModel::headerData(int section, Qt::Orientation orientation, int role) const
+{
+    Q_UNUSED(section);
+    if (orientation == Qt::Horizontal && role == Qt::DisplayRole)
+        return QString("Items");
+
+    return QVariant();
+}
+
+ContextTreeItem *ContextTreeModel::nodeFromIndex(const QModelIndex &idx) const
+{
+    if (idx.isValid())
+        return (ContextTreeItem *)idx.internalPointer();
+    return root;
+}
+
+static int getElementIndex(ElementType type)
+{
+    if (type == ElementType::BEL)
+        return 0;
+    if (type == ElementType::WIRE)
+        return 1;
+    if (type == ElementType::PIP)
+        return 2;
+    if (type == ElementType::NET)
+        return 3;
+    if (type == ElementType::CELL)
+        return 4;
+    return -1;
+}
+
+ContextTreeItem *ContextTreeModel::nodeForIdType(const ElementType type, const QString name) const
+{
+    int index = getElementIndex(type);
+    if (type != ElementType::NONE && nameToItem[index].contains(name))
+        return nameToItem[index].value(name);
+    return nullptr;
+}
+
+QModelIndex ContextTreeModel::indexFromNode(ContextTreeItem *node)
+{
+    ContextTreeItem *parent = node->parent();
+    if (parent == root)
+        return QModelIndex();
+    return createIndex(parent->indexOf(node), 0, node);
+}
+
+Qt::ItemFlags ContextTreeModel::flags(const QModelIndex &index) const
+{
+    ContextTreeItem *node = nodeFromIndex(index);
+    return Qt::ItemIsEnabled | (node->type() != ElementType::NONE ? Qt::ItemIsSelectable : Qt::NoItemFlags);
+}
+NEXTPNR_NAMESPACE_END
\ No newline at end of file
diff --git a/gui/treemodel.h b/gui/treemodel.h
new file mode 100644
index 00000000..a85c290a
--- /dev/null
+++ b/gui/treemodel.h
@@ -0,0 +1,93 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Miodrag Milanovic <miodrag@symbioticeda.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#ifndef TREEMODEL_H
+#define TREEMODEL_H
+
+#include <QAbstractItemModel>
+#include "nextpnr.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+enum class ElementType
+{
+    NONE,
+    BEL,
+    WIRE,
+    PIP,
+    NET,
+    CELL,
+    GROUP
+};
+
+class ContextTreeItem
+{
+  public:
+    ContextTreeItem();
+    ContextTreeItem(QString name);
+    ContextTreeItem(IdString id, ElementType type, QString name);
+    ~ContextTreeItem();
+
+    void addChild(ContextTreeItem *item);
+    int indexOf(ContextTreeItem *n) const { return children.indexOf(n); }
+    ContextTreeItem *at(int idx) const { return children.at(idx); }
+    int count() const { return children.count(); }
+    ContextTreeItem *parent() const { return parentNode; }
+    IdString id() const { return itemId; }
+    ElementType type() const { return itemType; }
+    QString name() const { return itemName; }
+    void sort();
+  private:
+    ContextTreeItem *parentNode;
+    QList<ContextTreeItem *> children;
+    IdString itemId;
+    ElementType itemType;
+    QString itemName;
+};
+
+class ContextTreeModel : public QAbstractItemModel
+{
+  public:
+    ContextTreeModel(QObject *parent = nullptr);
+    ~ContextTreeModel();
+
+    void loadData(Context *ctx);
+    void updateData(Context *ctx);
+    ContextTreeItem *nodeFromIndex(const QModelIndex &idx) const;
+    QModelIndex indexFromNode(ContextTreeItem *node);
+    ContextTreeItem *nodeForIdType(const ElementType type, const QString name) const;
+    // Override QAbstractItemModel methods
+    int rowCount(const QModelIndex &parent = QModelIndex()) const Q_DECL_OVERRIDE;
+    int columnCount(const QModelIndex &parent = QModelIndex()) const Q_DECL_OVERRIDE;
+    QModelIndex index(int row, int column, const QModelIndex &parent = QModelIndex()) const Q_DECL_OVERRIDE;
+    QModelIndex parent(const QModelIndex &child) const Q_DECL_OVERRIDE;
+    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const Q_DECL_OVERRIDE;
+    QVariant headerData(int section, Qt::Orientation orientation, int role) const Q_DECL_OVERRIDE;
+    Qt::ItemFlags flags(const QModelIndex &index) const Q_DECL_OVERRIDE;
+
+  private:
+    ContextTreeItem *root;
+    QMap<QString, ContextTreeItem *> nameToItem[6];
+    ContextTreeItem *nets_root;
+    ContextTreeItem *cells_root;
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif // TREEMODEL_H