Initial slides commit

13 files changed, 477 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
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+++ b/.gitignore
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+output/
+*.aux
+*.log
+*.nav
+*.out
+*.pdf
+*.snm
+*.toc
+*.vrb
diff --git a/Makefile b/Makefile
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+TEXFLAGS ?= -halt-on-error -output-format pdf -output-directory output --shell-escape
+TITLE = slides
+
+.PHONY: all clean
+
+all: output/$(TITLE).pdf
+
+output:
+	mkdir output
+
+output/$(TITLE).pdf: $(TITLE).tex output
+	pdflatex $(TEXFLAGS) '\providecommand\locale{en}\input{$(TITLE).tex}'
+	pdflatex $(TEXFLAGS) '\providecommand\locale{en}\input{$(TITLE).tex}'
+
+clean:
+	rm -rf output svg-inkscape
diff --git a/img/mesa-androidmk.png b/img/mesa-androidmk.png
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+++ b/img/mesa-androidmk.png
diff --git a/img/replicant.png b/img/replicant.png
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diff --git a/slides.tex b/slides.tex
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+\documentclass[aspectratio=169]{beamer}
+
+\mode<presentation> {
+\usetheme{Madrid}
+  \setbeamertemplate{authors}{}
+  % Remove navigation symbols.
+  \setbeamertemplate{navigation symbols}{}
+}
+
+\usepackage{color}
+\usepackage{listings}
+%\usepackage[utf8]{inputenc}
+%\usepackage{graphicx}
+%\usepackage[font=tiny,skip=0pt]{caption}
+%\usepackage{array}
+%\usepackage{verbatim}
+
+\graphicspath{{img/}}
+
+% Use symbols instead of numerals for footnotes.
+\renewcommand{\thefootnote}{\fnsymbol{footnote}}
+% Reset footnote counter every section.
+\makeatletter
+\@addtoreset{footnote}{subsection}
+\makeatother
+
+\newcommand{\iconframe}[2] {
+  \begin{minipage}[t]{2.5em}
+    \includegraphics[width=\textwidth]{app-icons/#1}
+    \captionof*{figure}{#2}
+  \end{minipage}
+}
+
+\title[Android's build system is messier than your distro's]{Android's build system is messier than your distro's}
+\author{Denis `GNUtoo' Carikli \and Ricardo `Grim' Cabrita}
+\institute[Replicant]{Replicant}
+\date{}
+
+
+\begin{document}
+
+
+% # Android's build system is messier than your distro's
+% The first step in the development of an Android distribution is coming to terms
+% with the Android Open Source Project (AOSP) peculiar build system. Despite
+% modular, AOSP's build system is quite complex and unlike those used in most
+% other distributions. For instance, it lacks the concept of packages and expects
+% sub-projects to be explicitly made compatible with it.
+\begin{frame}
+  \maketitle
+\end{frame}
+
+\lstset{
+  basicstyle=\scriptsize\ttfamily,
+  keywordstyle=\color{blue},
+  stringstyle=\color{orange},
+  breaklines=true,
+}
+
+% ## AOSP build system internals
+% Until version 7 AOSP used a Makefile based system which, in contrast to other
+% Make based build systems, didn't rely on recursive Makefiles that find and
+% invoke other Makefiles contained in subdirectories. Rather, it used a custom
+% script that explores all subdirectories in the source directory in search of
+% Android.mk files, which describe how a local module is built and handled. The
+% configuration of this system also differed from others such as GNU autotools or
+% kernel-style menuconfig, relying instead on variables that are set either as
+% part of the shell environment or statically and ahead of time on product and
+% device Makefiles.
+% As AOSP got larger this system became slow, error prone and hard to scale and
+% test. To fix this, the Makefile-based system is getting replaced by Soong. Soong
+% replaces Makefiles with Blueprint files, simpler declarative JSON-like
+% descriptions of modules, that get translated into a Ninja manifest describing
+% the commands that need to be run. This approach takes advantage of Ninja's
+% outstanding performance while sparing developers from it's complex build
+% language. During the transition period the remaining Makefiles are translated
+% to Ninja by Kati instead of being executed directly.
+% The transition to Soong solved the performance issue of AOSP's builds but got
+% short of taking it closer to the modularity and flexibility found in most
+% GNU/Linux distributions.
+\section{BuildSystemIntro}
+
+\begin{frame}[fragile]
+  \frametitle{The Build System}
+  Before {\bf Android 7} (2006-2016)
+  \begin{itemize}
+    \item Makefile based
+    \item Finds and joins all {\bf Android.mk} files in one
+    \item Limited configuration during build
+    \item Error prone
+    \item Slow and unscalable
+  \end{itemize}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{The Build System}
+  Barebones Android.mk file example
+  \begin{block}{}
+    \lstinputlisting{txt/android-mk-example}
+  \end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{The Build System}
+  From {\bf Android 7} onwards (2016-Now)
+  \begin{itemize}
+    \item {\bf Soong Build System}
+    \item {\bf Blueprint files} are replacing the old {\bf Makefiles}
+    \item {\bf Blueprint files} are converted to a {\bf Ninja} manifest
+    \item Remaining {\bf Makefiles} get translated to {\bf Ninja} by {\bf Kati}
+  \end{itemize}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{The Build System}
+  \begin{itemize}
+    \item {\bf Blueprint files} are simple to write
+    \item {\bf Ninja} is fast
+    \item Addresses performance issues
+    \item Falls short of addressing the lack of modulatiy and flexibility
+  \end{itemize}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{The Build System}
+  Barebones Android.bp file example
+  \begin{block}{}
+    \lstinputlisting{txt/android-bp-example}
+  \end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Workflow}
+  \framesubtitle{Getting the source tree}
+  Initialize the repository
+  \begin{block}{}
+    \begin{lstlisting}
+repo init -u https://git.replicant.us/replicant/manifest.git -b replicant-9
+    \end{lstlisting}
+  \end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Workflow}
+  \framesubtitle{Getting the source tree}
+  Inside a manifest file
+  \begin{block}{}
+    \lstinputlisting{txt/manifest-example}
+  \end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Workflow}
+  \framesubtitle{Getting the source tree}
+  Download the source tree
+  \begin{block}{}
+    \begin{lstlisting}
+repo sync
+    \end{lstlisting}
+  \end{block}
+  Contemplate disk usage
+  \begin{block}{}
+    \begin{lstlisting}
+du -h --summarize
+124GiB
+    \end{lstlisting}
+  \end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Workflow}
+  \framesubtitle{Configuring the build}
+  Initialize the build environment
+  \begin{block}{}
+    \begin{lstlisting}
+source build/envsetup.sh
+    \end{lstlisting}
+  \end{block}
+  \begin{block}{}
+    \lstinputlisting{txt/envsetup-commands}
+  \end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Workflow}
+  \framesubtitle{Configuring the build}
+  Pick your menu
+  \begin{block}{}
+    \begin{lstlisting}
+lunch replicant_i9305-userdebug
+    \end{lstlisting}
+  \end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Workflow}
+  \framesubtitle{Build}
+  Start cooking
+  \begin{block}{}
+    \begin{lstlisting}
+m bacon
+    \end{lstlisting}
+  \end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Workflow}
+  \framesubtitle{Upload to device}
+  \begin{block}{}
+    \begin{lstlisting}
+ls out/target/product/i9305
+    \end{lstlisting}
+  \end{block}
+  \begin{block}{}
+    \lstinputlisting{txt/output-folder-example}
+  \end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Workflow}
+  \framesubtitle{Upload to device}
+  Flash the images directly through download mode
+  \begin{block}{}
+    \begin{lstlisting}
+heimdall flash --BOOT boot.img --SYSTEM system.img
+    \end{lstlisting}
+  \end{block}
+  Or install through recovery mode
+  \begin{block}{}
+    \begin{lstlisting}
+adb sideload replicant-ota-eng.user.zip
+    \end{lstlisting}
+  \end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Workflow}
+  \framesubtitle{Modify a module}
+  \begin{block}{}
+    \begin{lstlisting}
+cd external/mesa3d
+vim src/gallium/drivers/llvmpipe/Android.mk
+mma
+m snod
+heimdall flash --SYSTEM system.img
+    \end{lstlisting}
+  \end{block}
+\end{frame}
+
+% ## Building AOSP vs building GNU/Linux distros
+% Virtually all GNU/Linux distributions use package managers, which wrap around
+% the build system of choice of the software being packaged and bundle it into a
+% reusable package that can be installed for direct use and or as a dependency for
+% others. These packages can also be delivered and updated via software
+% repositories after the initial installation of the distribution. In AOSP, there
+% is no package manager. Most software components are built from git repositories
+% and bundled into a single image that includes the majority of the distribution.
+% Updating a single component thus becomes much harder.
+% Besides the core components of AOSP, community distributions tend to use several
+% external projects like Mesa and the Linux kernel. These must usually be
+% integrated into the build tree as they depend on AOSP's libc. In such cases,
+% Google expects the project maintainers to keep their project compatible with
+% AOSP's build system, i.e. nowadays they expect the project to have its own
+% Blueprint files.
+% This contrasts with GNU/Linux distributions, which provide ways to build each
+% project in its own native build system and then incorporate it into the distro
+% image as an independent package.
+\section{ComparisonToOtherDistros}
+\begin{frame}[fragile]
+  \frametitle{Comparison to other distros}
+  \begin{itemize}
+    \item Recipe maintenance
+    \item Software delivery
+  \end{itemize}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Comparison to other distros}
+  \framesubtitle{Recipe maintenance}
+  {\bf GNU/Linux}: Most distros use package managers
+  \begin{block}{}
+    \lstinputlisting{txt/pkgbuild-example}
+  \end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Comparison to other distros}
+  \framesubtitle{Recipe maintenance}
+  {\bf Android}: Projects are expected to keep their own Android.mk
+  \includegraphics[width=\linewidth,height=\textheight,keepaspectratio]{mesa-androidmk}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Comparison to other distros}
+  \framesubtitle{Recipe maintenance}
+  \begin{itemize}
+    \item Control of the build is out of the hands of the distro
+    \item Troublesome to modify build recipes
+    \item Disregard for the project's prefered build system
+    \item Changes to the recipe have to be made upstream least the distro wishes to maintain yet another fork
+  \end{itemize}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Comparison to other distros}
+  \framesubtitle{Software delivery}
+  {\bf GNU/Linux}: Packages are delivered through software repositories
+  \begin{block}{}
+    \lstinputlisting{txt/gnulinux-packages}
+  \end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Comparison to other distros}
+  \framesubtitle{Software delivery}
+  {\bf Android}: Entire system is delivered through a single package
+  \begin{block}{}
+    \lstinputlisting{txt/android-single-package}
+  \end{block}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Comparison to other distros}
+  \framesubtitle{Software delivery}
+  \begin{itemize}
+    \item User has to download the entire system in order to update a single component
+    \item Updates are rarely delivered in a timely manner
+  \end{itemize}
+\end{frame}
+
+
+% ## Replicant's stake
+% Replicant, a fully free-software AOSP distribution, is now undergoing intense
+% work to make it as sustainable as possible by sharing code with GNU/Linux
+% distributions. For instance, Replicant's next release (Replicant 9) is being
+% developed on top of mainline Linux and Mesa.
+% This comes with the disadvantage of having to deal with the unsuitability of AOSP
+% build system to handle external projects. Long hours of development time are
+% lost due to the incapability of AOSP to detect changes in projects that haven't
+% been converted to Blueprint, such as Linux, Mesa or SwiftShader.
+% Replicant is thus seeking to discuss and ultimately decide on a sustainable way
+% to go deal with external software components.
+% Supporting Blueprint could be advantageous for Replicant, due to its faster
+% build times, selective recompilation when source files change on disk and
+% ability to support multiple Android versions without convoluted conditional
+% cases. However it would be preferable if Android supported some form of packages
+% similarly to GNU/Linux distributions. Adding and maintaining Blueprint support
+% in all external software components can be incredibly time consuming and could
+% even be unsustainable.
+\section{Replicant}
+\begin{frame}[fragile]
+  \frametitle{Replicant's stake}
+  \begin{columns}
+    \begin{column}{0.2\textwidth}
+      \includegraphics[width=\textwidth]{replicant}
+    \end{column}
+    \begin{column}{0.7\textwidth}
+      Fully free Android distribution running on several devices\\\bigskip
+      Now undergoing intense work to make it as sustainable as possible\\\bigskip
+      Spending a lot of development time on the build system's quirks\\\bigskip
+      Seeking to discuss on a sustainable way to deal with external software componentes
+    \end{column}
+  \end{columns}
+\end{frame}
+
+
+\end{document}
+
diff --git a/txt/android-bp-example b/txt/android-bp-example
new file mode 100644
index 0000000..c5a71e2
--- /dev/null
+++ b/txt/android-bp-example
@@ -0,0 +1,14 @@
+cc_binary {
+    name: "gzip",
+    srcs: ["src/test/generic.c"],
+    shared_libs: ["libz"],
+    arch: {
+        arm: {
+            srcs: ["src/test/arm.c"],
+        },
+        x86: {
+            srcs: ["src/test/x86.c"],
+        },
+    },
+}
+
diff --git a/txt/android-mk-example b/txt/android-mk-example
new file mode 100644
index 0000000..1478c26
--- /dev/null
+++ b/txt/android-mk-example
@@ -0,0 +1,15 @@
+LOCAL_PATH := $(call my-dir)
+include $(CLEAR_VARS)
+LOCAL_MODULE    := gzip
+LOCAL_SRC_FILES := src/test/generic.c
+LOCAL_SHARED_LIBRARIES := libz
+
+ifeq ($(TARGET_ARCH),arm)
+  LOCAL_SRC_FILES := src/test/arm.c
+else
+  ifeq($(TARGET_ARCH),x86)
+    LOCAL_SRC_FILES := src/test/x86.c
+  endif
+endif
+
+include $(BUILD_SHARED_LIBRARY)
diff --git a/txt/android-single-package b/txt/android-single-package
new file mode 100644
index 0000000..951a1aa
--- /dev/null
+++ b/txt/android-single-package
@@ -0,0 +1,2 @@
+du -h replicant-6.0-i9300.zip
+269M replicant-6.0-i9300.zip
diff --git a/txt/envsetup-commands b/txt/envsetup-commands
new file mode 100644
index 0000000..c6c779c
--- /dev/null
+++ b/txt/envsetup-commands
@@ -0,0 +1,9 @@
+- lunch:   lunch <product_name>-<build_variant>
+- croot:   Changes directory to the top of the tree.
+- m:       Makes from the top of the tree.
+- mm:      Builds all of the modules in the current directory.
+- mmm:     Builds all of the modules in the supplied directories.
+- cgrep:   Greps on all local C/C++ files.
+- jgrep:   Greps on all local Java files.
+- resgrep: Greps on all local res/*.xml files.
+- godir:   Go to the directory containing a file.
diff --git a/txt/gnulinux-packages b/txt/gnulinux-packages
new file mode 100644
index 0000000..62a41bd
--- /dev/null
+++ b/txt/gnulinux-packages
@@ -0,0 +1,8 @@
+pacman -Ss mesa
+extra/mesa 19.3.0-1 [installed: 19.2.7-1]
+    An open-source implementation of the OpenGL specification
+
+pacman -S mesa
+(...)
+Total Download Size:  20.19 MiB
+
diff --git a/txt/manifest-example b/txt/manifest-example
new file mode 100644
index 0000000..8eae98b
--- /dev/null
+++ b/txt/manifest-example
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<manifest>
+  <remote  name="aosp"
+           fetch="https://android.googlesource.com"
+           revision="refs/tags/android-9.0.0_r44" />
+(...)
+  <project path="device/samsung/i9305" name="replicant-9/device_samsung_i9305" remote="replicant-9" />
+  <project path="external/mesa3d" name="replicant-9/external_mesa3d" remote="replicant-9" />
+  <project path="frameworks/base" name="replicant-9/frameworks_base" remote="replicant-9" />
+  <project path="packages/apps/Dialer" name="LineageOS/android_packages_apps_Dialer" />
+(...)
+
diff --git a/txt/output-folder-example b/txt/output-folder-example
new file mode 100644
index 0000000..4c70f77
--- /dev/null
+++ b/txt/output-folder-example
@@ -0,0 +1,9 @@
+(...)
+boot.img
+replicant-ota-eng.user.zip
+ramdisk.img
+ramdisk-recovery.img
+recovery.img
+system.img
+userdata.img
+(...)
diff --git a/txt/pkgbuild-example b/txt/pkgbuild-example
new file mode 100644
index 0000000..44a5857
--- /dev/null
+++ b/txt/pkgbuild-example
@@ -0,0 +1,15 @@
+pkgbase=mesa
+pkgname=('vulkan-mesa-layer' 'opencl-mesa' 'vulkan-intel' 'vulkan-radeon' 'libva-mesa-driver' 'mesa-vdpau' 'mesa')
+pkgdesc="An open-source implementation of the OpenGL specification"
+pkgver=19.3.1
+(...)
+
+build() {
+  arch-meson mesa-$pkgver build \
+    -D b_lto=false \
+    -D platforms=x11,wayland,drm,surfaceless \
+    -D dri-drivers=i915,i965,r100,r200,nouveau \
+(...)
+  meson configure build
+  ninja -C build
+(...)