ladybird/Toolchain
Andrew Kaster cdbbe14062 LibC: Implement Itanium C++ ABI for static variable guards
This is __cxa_guard_acquire, __cxa_guard_release, and __cxa_guard_abort.

We put these symbols in a 'fake' libstdc++ to trick gcc into thinking it
has libstdc++. These symbols are necessary for C++ programs and not C
programs, so, seems file. There's no way to tell gcc that, for example,
the standard lib it should use is libc++ or libc. So, this is what we
have for now.

When threaded code enters a block that is trying to call the constructor
for a block-scope static, the compiler will emit calls to these methods
to handle the "call_once" nature of block-scope statics.

The compiler creates a 64-bit guard variable, which it checks the first
byte of to determine if the variable should be intialized or not.

If the compiler-generated code reads that byte as a 0, it will call
__cxa_guard_acquire to try and be the thread to call the constructor for
the static variable. If the first byte is 1, it will assume that the
variable's constructor was called, and go on to access it.

__cxa_guard_acquire uses one of the 7 implementation defined bytes of
the guard variable as an atomic 8 bit variable. To control a state
machine that lets each entering thread know if they gained
'initialization rights', someone is working on the varaible, someone is
working on the varaible and there's at least one thread waiting for it
to be intialized, or if the variable was initialized and it's time to
access it. We only store a 1 to the byte the compiler looks at in
__cxa_guard_release, and use a futex to handle waiting.
2020-05-20 08:37:50 +02:00
..
Patches Toolchain/Ports: Update to gcc 10.1.0 2020-05-16 09:51:31 +02:00
.gitignore Travis: Cache toolchain 2020-03-08 14:09:08 +01:00
BuildFuseExt2.sh Build: Allow building serenityOS ext2 root filesystem on macOS host 2019-12-27 02:19:55 +01:00
BuildIt_x86_64.sh Toolchain/Ports: Update to gcc 10.1.0 2020-05-16 09:51:31 +02:00
BuildIt.sh LibC: Implement Itanium C++ ABI for static variable guards 2020-05-20 08:37:50 +02:00
BuildPython.sh Toolchain: Fix python build script. 2020-01-25 09:09:52 +01:00
BuildQemu.sh Toolchain: Make BuildQemu.sh choose the correct ui library when building on OSX 2020-04-07 08:44:41 +02:00
CMakeToolchain.txt Toolchain: Fixup CMake toolchain script to install things in /usr 2019-12-25 23:17:10 +01:00
ComputeDependenciesHash.sh Services: Renamed from Servers 2020-05-08 21:57:44 +02:00
README.md Toolchain: Add QEMU build script and improve documentation 2019-11-11 21:29:56 +01:00

Serenity Toolchain - Building the Serenity operating system

This directory contains all toolchain related files. E.g. build scripts for the cross compilation toolchain and build toolchain for ports.

Cross Compile Toolchain

The cross compile toolchain contains

  • binutils 2.32

  • GCC 8.3.0

These are built from source with some patches applied.

Dependencies

  • Build Essentials

    sudo apt install build-essential curl libmpfr-dev libmpc-dev libgmp-dev
    
  • GCC 8

    sudo add-apt-repository ppa:ubuntu-toolchain-r/test
    sudo apt-get install gcc-8 g++-8
    sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-8 800 --slave /usr/bin/g++ g++ /usr/bin/g++-8
    
  • e2fsprogs

    sudo apt install e2fsprogs
    

Serenity (Full build)

If everything worked out, you now have the i686-pc-serenity toolchain ready and we can build Serenity.

Go into Kernel/ folder and build it:

./makeall.sh

Then take it for a spin:

./run

See next chapter for more options on running SerenityOS in an emulator.

Running SerenityOS in an emulator

To run SerenityOS in a specific emulator, call the ./run command in the Kernel/ folder:

./run

There are several emulators supported to run SerenityOS in:

  • Bochs

    sudo apt install bochs
    

    Add the b argument to the run script, to use bochs emulator:

    ./run b
    
  • QEMU QEMU with networking enabled is used by default, when no extra argument is passed to the run script. There are some extra arguments to run QEMU emulator with specific settings:

    Add the qn argument to the run script to use QEMU without networking:

    ./run qn
    

    Add the qgrub argument to the run script to use QEMU with grub bootloader:

    ./run qgrub
    

    Add the qtext argument to the run script to use QEMU with textmode:

    ./run qtext
    

    Note: there is a problem with the PS/2 keyboard/mouse emulation in QEMU 2.11.1 as packaged in Ubuntu's LTS releases. If you have any strange behaviour with missing keyboard inputs or jittery mouse movement, try building QEMU from source as described in QEMU. 2.12.1, 3.0.1, 3.1.0, and 4.0.0 are all confirmed as working when built from source.

QEMU installation / compilation

If your distribution contains a QEMU version > 2.11.1, then you can just install it via

sudo apt install qemu-system-i386 qemu-utils

If that is not the case, you can build QEMU from sources with the provided script BuildQemu.sh. To do so, some build dependencies have to be installed first:

sudo apt-get build-dep qemu
sudo apt-get install libgtk-3-dev

The source-repositories of your distribution have to be enabled to install the build-dep's.

BuildQemu.sh has been tested with QEMU 3.0.0 and 4.1.0 (which is default). If you want to build QEMU 3.0.0, change the variable QEMU_VERSION and QEMU_MD5SUM accordingly:

QEMU_VERSION="qemu-3.0.0"
QEMU_MD5SUM="${QEMU300_MD5SUM}"

Passing custom arguments to QEMU

You can modify the environment variable SERENITY_EXTRA_QEMU_ARGS to your needs or hand it over directly before the run command:

SERENITY_EXTRA_QEMU_ARGS="-nographic" ./run qtext