How to build V8 on Raspberry Pi (3 model B) ?

[aleReimondo]

Hi,

I have made most steps detailed in V8 wiki to download prerequisites and V8 sources.

Up to "gclient sync" all look ok, but the page at

  https://github.com/v8/v8/wiki/Building-with-GN

is not clear to me what should I run now to v8gen and then gn

 to build V8.

Trying to make and/or gyp way had not succeded here.

The shell executable is what I need to build on the Raspberry.

any help/reccomendation will be appreciated,

Ale.

[Ben Noordhuis]

I think you want `tools/dev/v8gen.py arm.release && ninja -C
out.gn/arm.release d8`?

[aleReimondo]

Thank you for your fast response!

I tried tools/dev/v8gen.py arm.release

 but got error

-------------------------------------------------------------------------------

pi@raspberrypi:~/v8 $ tools/dev/v8gen.py arm.release -vv

################################################################################

/usr/bin/python -u tools/mb/mb.py gen -f infra/mb/mb_config.pyl -m developer_default -b arm.release out.gn/arm.release

  

  Writing """\

  is_debug = false

  target_cpu = "x86"

  v8_target_cpu = "arm"

  """ to /home/pi/v8/out.gn/arm.release/args.gn.

  

  /home/pi/v8/buildtools/linux64/gn gen out.gn/arm.release --check

  Traceback (most recent call last):

    File "tools/mb/mb.py", line 60, in Main

      ret = self.args.func()

    File "tools/mb/mb.py", line 257, in CmdGen

      return self.RunGNGen(vals)

    File "tools/mb/mb.py", line 786, in RunGNGen

      ret, _, _ = self.Run(cmd, env=env)

    File "tools/mb/mb.py", line 1380, in Run

      ret, out, err = self.Call(cmd, env=env, buffer_output=buffer_output)

    File "tools/mb/mb.py", line 1394, in Call

      env=env)

    File "/usr/lib/python2.7/subprocess.py", line 710, in __init__

      errread, errwrite)

    File "/usr/lib/python2.7/subprocess.py", line 1335, in _execute_child

      raise child_exception

  OSError: [Errno 8] Exec format error

Traceback (most recent call last):

  File "tools/dev/v8gen.py", line 304, in <module>

    sys.exit(gen.main())

  File "tools/dev/v8gen.py", line 298, in main

    return self._options.func()

  File "tools/dev/v8gen.py", line 166, in cmd_gen

    gn_outdir,

  File "tools/dev/v8gen.py", line 208, in _call_cmd

    stderr=subprocess.STDOUT,

  File "/usr/lib/python2.7/subprocess.py", line 573, in check_output

    raise CalledProcessError(retcode, cmd, output=output)

subprocess.CalledProcessError: Command '['/usr/bin/python', '-u', 'tools/mb/mb.py', 'gen', '-f', 'infra/mb/mb_config.pyl', '-m', 'developer_default', '-b', 'arm.release', 'out.gn/arm.release']' returned non-zero exit status 1

-------------------------------------------------------------------------------

Ale 

[Ben Noordhuis]

Hm, that looks like a bug to me - target_arch should be "arm", not
"x86" and it shouldn't try to compile using the x86_64 version of
clang. Consider filing a bug report.

[Jakob Kummerow]

It's not exactly a bug. v8gen.py, by design, replicates the configuration of the respective buildbot, and that buildbot uses arm simulator builds.

It's really easy to change the build configuration locally though: just run gn args out.gn/arm.release, and in the editor that opens, set target_cpu = "arm".

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[aleReimondo]

Hi,

When I run gn (with and without arguments) I get the same error.

Is there an option to set configuration manually?

pi@raspberrypi:~/v8 $ gn args

Traceback (most recent call last):

  File "/home/pi/depot_tools/gn.py", line 38, in <module>

    sys.exit(main(sys.argv))

  File "/home/pi/depot_tools/gn.py", line 33, in main

    return subprocess.call([gn_path] + args[1:])

  File "/usr/lib/python2.7/subprocess.py", line 522, in call

    return Popen(*popenargs, **kwargs).wait()

  File "/usr/lib/python2.7/subprocess.py", line 710, in __init__

    errread, errwrite)

  File "/usr/lib/python2.7/subprocess.py", line 1335, in _execute_child

    raise child_exception

OSError: [Errno 8] Exec format error

Ale

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[aleReimondo]

The gn command is running executable gn at ~/v8/buildtools/linux64

IMO the binary executable was downloaded from V8 repo,

 and do not have the correct contents to be run here

pi@raspberrypi:~/v8/buildtools/linux64 $ ./gn --help

bash: ./gn: cannot execute binary file: Formato de ejecutable incorrecto

So, the gn.py is not running because it is trying to run binary code

 of wrong target.

Ale

[aleReimondo]

Now starting from a new installation to ensure the malfunction of the tools download is reproducible on clean installation of Raspbian...

Ale

[aleReimondo]

Confirmed the malfunction of the build toolset on the Raspberry Pi.

It has been reproduced started from clean SDCard (Raspbian OS) and following wiki procedures to build V8 without observing any other issues during installation and setup.

So, I will consider this a BUG of Chrome toolset and wait to be repaired soon.

IMHO the downloaded binary of gn is wrong on the Raspery Pi 3 (Raspbian OS).

Ale

p.d. Why are we downloading binaries? the reason to use py scripting is to do not transfer binary...  please remove scripting (best) or binary downloads in the toolset :-P

[aleReimondo]

Issue reported at https://bugs.chromium.org/p/v8/issues/detail?id=6458

 

[Jakob Kummerow]

On Fri, Jun 2, 2017 at 5:10 PM, aleReimondo <aleRe...@smalltalking.net> wrote:

Confirmed the malfunction of the build toolset on the Raspberry Pi.

It has been reproduced started from clean SDCard (Raspbian OS) and following wiki procedures to build V8 without observing any other issues during installation and setup.

So, I will consider this a BUG of Chrome toolset and wait to be repaired soon.

IMHO the downloaded binary of gn is wrong on the Raspery Pi 3 (Raspbian OS).

Interesting observation. 

Yes, it looks like it is assumed that nobody builds on an ARM device; this site says:

Due to the lack of ARM hardware with the grunt to build Chromium native, cross compiling is currently the recommended method of building for ARM.

V8 has instructions for cross-compiling: https://github.com/v8/v8/wiki/Cross-compiling-for-ARM (these are targeting Android, but it should be easy to adapt them).

As an alternative: while there don't seem to be pre-built gn binaries for you to download, you can build your own gn from source. However, I'm not familiar with that process so I can't give more detailed hints, I only know that it is possible.

 

Ale

p.d. Why are we downloading binaries? the reason to use py scripting is to do not transfer binary...  please remove scripting (best) or binary downloads in the toolset :-P

Well, gn is a binary tool, that's by design... The Python scripts around it are just for convenience.

[Jakob Kummerow]

On Fri, Jun 2, 2017 at 5:37 PM, aleReimondo <aleRe...@smalltalking.net> wrote:

Issue reported at https://bugs.chromium.org/p/v8/issues/detail?id=6458

Don't hold your breath, but feel free to help ;-)

[aleReimondo]

Thank you Jakob,

I will try to read and build gn :-)

On the paragraph:

 

Well, gn is a binary tool, that's by design... The Python scripts around it are just for convenience.

So, the use of build tools can impose security risks.

Ale.