Prerequisites

• a Linux/Mac workstation
• v8 r12178 (on Google Code) or later
• an Android emulator or device with matching USB cable
• make sure building with GYP works

Get the code

• Use the instructions from https://code.google.com/p/v8-wiki/wiki/UsingGit to get the code
• Once you need to add the android dependencies:

v8$ echo "target_os = ['android']" >> ../.gclient && gclient sync --nohooks

• The sync will take a while the first time as it downloads the Android NDK to v8/third_party
• If you want to use a different NDK, you need to set the gyp variable android_ndk_root

Get the Android SDK

• tested version: r15
• download the SDK from http://developer.android.com/sdk/index.html
• extract it
• install the “Platform tools” using the SDK manager that you can start by running tools/android
• now you have a platform_tools/adb binary which will be used later; put it in your PATH or remember where it is

Set up your device

• Enable USB debugging (Gingerbread: Settings > Applications > Development > USB debugging; Ice Cream Sandwich: Settings > Developer Options > USB debugging)
• connect your device to your workstation
• make sure adb devices shows it; you may have to edit udev rules to give yourself proper permissions
• run adb shell to get an ssh-like shell on the device. In that shell, do:

cd /data/local/tmp
mkdir v8
cd v8

Push stuff onto the device

• make sure your device is connected
• from your workstation's shell:

adb push /file/you/want/to/push /data/local/tmp/v8/

Compile V8 for Android

Currently two architectures (android_arm and android_ia32) are supported, each in debug or release mode. The following steps work equally well for both ARM and ia32, on either the emulator or real devices.

• compile:

make android_arm.release -j16

• push the resulting binary to the device:

adb push out/android_arm.release/d8 /data/local/tmp/v8/d8

• the most comfortable way to run it is from your workstation's shell as a one-off command (rather than starting an interactive shell session on the device), that way you can use pipes or whatever to process the output as necessary:

adb shell /data/local/tmp/v8/d8 <parameters>

• warning: when you cancel such an “adb shell whatever” command using Ctrl+C, the process on the phone will sometimes keep running.
• Alternatively, use the .check suffix to automatically push test binaries and test cases onto the device and run them.

make android_arm.release.check

Profile

• compile a binary, push it to the device, keep a copy of it on the host

make android_arm.release -j16
adb push out/android_arm.release/d8 /data/local/tmp/v8/d8-version.under.test
cp out/android_arm.release/d8 ./d8-version.under.test

• get a profiling log and copy it to the host:

adb shell /data/local/tmp/v8/d8-version.under.test benchmark.js --prof
adb pull /data/local/tmp/v8/v8.log ./

• open v8.log in your favorite editor and edit the first line to match the full path of the d8-version.under.test binary on your workstation (instead of the /data/local/tmp/v8/ path it had on the device)
• run the tick processor with the host's d8 and an appropriate nm binary:

cp out/ia32.release/d8 ./d8  # only required once
tools/linux-tick-processor --nm=$ANDROID_NDK_ROOT/toolchain/bin/arm-linux-androideabi-nm

Compile SpiderMonkey for Lollipop

cd firefox/js/src
autoconf2.13
./configure \
  --target=arm-linux-androideabi \
  --with-android-ndk=$ANDROID_NDK_ROOT \
  --with-android-version=21 \
  --without-intl-api \
  --disable-tests \
  --enable-android-libstdcxx \
  --enable-pie
make
adb push -p js/src/shell/js /data/local/tmp/js