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Alexander David Frick edited this page Apr 7, 2023 · 4 revisions

Checking out and Building Thorium for Windows  

System Requirements

  • A 64-bit machine with at least 8GB of RAM. More than 16GB is highly recommended.
  • At least 75GB of free disk space on an NTFS-formatted hard drive. FAT32 will not work, as some of the Git packfiles are larger than 4GB.
  • An appropriate version of Visual Studio, as described below.
  • Windows 10 1709 or newer.

Setting up Windows

Visual Studio

Chromium requires Visual Studio 2019 (>=16.0.0) to build, but Visual Studio 2022 (>=17.0.0) is preferred. Visual Studio can also be used to debug Chromium, and version 2022 is preferred for this as it handles Chromium's large debug information much better. The clang-cl compiler is used, but Visual Studio's header files, libraries, and some tools are required. Visual Studio Community Edition will work. You must install the "Desktop development with C++" component and the "MFC/ATL support" sub-components. This can be done from the command line by passing these arguments to the Visual Studio installer (see below for ARM64 instructions):

VisualStudioSetup.exe --add Microsoft.VisualStudio.Workload.NativeDesktop --add Microsoft.VisualStudio.Component.VC.ATLMFC --includeRecommended

If you want to build for Windows on ARM64 then some extra arguments are needed. The full set for that case is:

VisualStudioSetup.exe --add Microsoft.VisualStudio.Workload.NativeDesktop --add Microsoft.VisualStudio.Component.VC.ATLMFC --add Microsoft.VisualStudio.Component.VC.Tools.ARM64 --add Microsoft.VisualStudio.Component.VC.MFC.ARM64 --includeRecommended
  • You must have the version 10.1.22621.755 Windows 11 SDK installed. This can be installed separately or by checking the appropriate box in the Visual Studio Installer (Note that MSVS 2022 will try to install the 22000 version by default, uncheck this and check the 22621 version). There is also experimental support for the Windows 11 10.1.22000.755 version.

The SDK Debugging Tools must also be installed. If the Windows 10 SDK was installed via the Visual Studio installer, then they can be installed by going to: Control Panel → Programs → Programs and Features → Select the "Windows Software Development Kit" → Change → Change → Check "Debugging Tools For Windows" → Change. Or, you can download the standalone SDK installer and use it to install the Debugging Tools.

Install depot_tools

Download the depot_tools bundle and extract it to C:\src\depot_tools.

***note Warning: DO NOT use drag-n-drop or copy-n-paste extract from Explorer, this will not extract the hidden “.git” folder which is necessary for depot_tools to autoupdate itself. You can use “Extract all…” from the context menu, or 7-Zip though.

Add depot_tools to the start of your PATH (must be ahead of any installs of Python). Note that environment variable names are case insensitive.

Assuming you unzipped the bundle to C:\src\depot_tools, open:

Control Panel → System and Security → System → Advanced system settings

If you have Administrator access, Modify the PATH system variable and put C:\src\depot_tools at the front, by clicking "Move Up". (Or at least in front of any directory that might already have a copy of Python or Git).

If you don't have Administrator access, you can add a user-level PATH environment variable by opening:

Control Panel → System and Security → System → Search for "Edit environment variables for your account"

Add C:\src\depot_tools at the front. Note: If your system PATH has a Python in it, you will be out of luck.

Also, add a DEPOT_TOOLS_WIN_TOOLCHAIN environment variable in the same way, and set it to 0. This tells depot_tools to use your locally installed version of Visual Studio (by default, depot_tools will try to use a google-internal version).

You should also set the variable vs2019_install or vs2022_install to your installation path of Visual Studio 19 or 22, like vs2019_install = C:\Program Files (x86)\Microsoft Visual Studio\2019\Community for Visual Studio 2019, or vs2022_install = C:\Program Files\Microsoft Visual Studio\2022\Community for Visual Studio 2022.

Once all of this is done, we will download some infra archives using gclient.
From a cmd.exe shell, run:

gclient

On first run, gclient will install all the Windows-specific bits needed to work with the code, including msysgit and Python.

  • If you run gclient from a non-cmd shell (e.g., cygwin, PowerShell), it may appear to run properly, but msysgit, python, and other tools may not get installed correctly.
  • If you see strange errors with the file system on the first run of gclient, you may want to disable Windows Indexing.

Check Python install

After running gclient open a command prompt and type where python and confirm that the depot_tools python.bat comes ahead of any copies of python.exe. Failing to ensure this can lead to overbuilding when using gn - see crbug.com/611087.

App Execution Aliases in Windows 10/11 can conflict with other installations of python on the system so disable these for 'python.exe' and 'python3.exe' by opening 'App execution aliases' section of Control Panel and unticking the boxes next to both of these that point to 'App Installer'.

Downloading the Chromium code

First, configure Git:

git config --global user.name "My Name"
git config --global user.email "my-name@chromium.org"
git config --global core.autocrlf false
git config --global core.filemode false
git config --global branch.autosetuprebase always

Create a chromium directory in C:\src for the checkout and change to it.

cd / && cd src && mkdir chromium && cd chromium

Run the fetch tool from depot_tools to check out the code and its dependencies.

fetch chromium

If you don't want the full repo history, you can save a lot of time by adding the --no-history flag to fetch.

Expect the command to take 30 minutes on even a fast connection, and many hours on slower ones.

When fetch completes, it will have created a hidden .gclient file and a directory called src in the working directory. The remaining instructions assume you have switched to this directory (i.e. C:\src\chromium\src):

cd src

Optional: You can also build with API keys if you want your build to talk to some Google services like Google Sync, Translate, and GeoLocation.   Thorium has its own keys in a private repository, if you are a builder or would like access to them, contact me. Otherwise, for personal or development builds, you can create your own keys and add yourself to google-browser-signin-testaccounts to enable Sync.

Downloading the Thorium code

You can either use git clone, or download a .zip from the repo. It should be placed side by side with the Chromium directory in C:\src.
Using Git:

git clone https://github.com/Alex313031/Thorium.git

Or download the .zip (Make sure to rename the extracted dir to just Thorium, not Thorium-main). https://github.com/Alex313031/Thorium/archive/refs/heads/main.zip

Setting up the build

First, we need to copy the Thorium source files over the Chromium tree. Run the setup.bat script in Thorium\win_scripts to automate this.

cd C:\src\Thorium\win_scripts && setup.bat

It will drop you back to C:\src\chromium\src, which is where the rest of the commands will be carried out.

Next, we will download the PGO profile for Thorium, which changes with every revision. Run:

python3 tools\update_pgo_profiles.py --target=win64 update --gs-url-base=chromium-optimization-profiles/pgo_profiles

This will download a *.profdata file, looking something like chrome-win64-main-1659409120-058034bd778fed227d12a29fd0edd0942810dbf8.profdata.
Take note of this, as we will be using it in the args.gn below.

Creating the build directory

Chromium & Thorium use Ninja as its main build tool along with a tool called GN to generate .ninja files. Create the build directory by running:

gn args out\thorium

This will open up notepad.exe, and this is where we will specify build arguments ("args") which direct Ninja on how to lay out the build directory tree. We will be copy/pasting the contents of the win_args.gn file (from C:\src\Thorium\infra\win_args.gn) into notepad. Notice the three lines at the top, related to API Keys. It is fine to leave them blank, or add the ones you have made.
At the bottom, though, notice the line that says pgo_data_path = "". This is where we will put the full path to the PGO profile data file we downloaded earlier.

That line should look something like:

pgo_data_path = "C:\src\chromium\src\chrome\build\pgo_profiles\chrome-win64-main-1659409120-058034bd778fed227d12a29fd0edd0942810dbf8.profdata"

Build Thorium

Build Thorium, and the other things like chromedriver and thorium_shell with Ninja using the command:

autoninja -C out\thorium chrome chromedriver thorium_shell setup mini_installer -j8

(Where -j# can be any number, and should generally be set to the number of cores on your CPU).

autoninja is a wrapper that automatically provides optimal values for the arguments passed to ninja.

You can get a list of all of the other build targets from GN by running gn ls out\thorium from the command line. To compile one, pass to Ninja the GN label with no preceding "//" (so for //chrome/test:unit_tests use autoninja -C out/Default chrome/test:unit_tests).

Install/Run Thorium

Once it is built, you can simply install the browser.

out\thorium\mini_installer.exe

Update your checkout

To update an existing Chromium checkout, you should run the trunk.bat script in win_scripts:

cd C:\src\Thorium\win_scripts && trunk.bat

(This script will also download the latest PGO profile data file at the end; useful when making fresh builds.)

This syncs the subrepositories to the appropriate versions, deleting those that are no longer needed, and re-runs the hooks as needed.

To update an existing Thorium checkout, just download the latest .zip, or do a git pull:

git pull origin main

Happy Thorium Building!

Thanks for using Thorium!

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