Siso Tips

When using Siso, there are a few tips that are particularly useful in Chromium codebase.

[TOC]

Compile a single file

Siso/Ninja supports a special syntax ^ to compile a single object file specifying the source file. For example, autoninja -C out/Default ../../base/logging.cc^ compiles obj/base/base/logging.o.

In addition to foo.cc^, Siso also supports foo.h^ syntax to compile the corresponding foo.o if it exists.

On Windows, you need to add ^^ to preserve the trailing ^.

$ autoninja -C out\Default ..\..\base\logging.cc^^

If you run a bash shell, you can use the following script to ease invocation:

#!/bin/sh
files=("${@/#/..\/..\/}")
autoninja -C out/Default ${files[@]/%/^^}

This script assumes it is run from src and your output dir is out/Default; it invokes autoninja to compile all given files. If you place it in your $PATH and name it e.g. compile, you can invoke like this:

$ pwd  # Just to illustrate where this is run from
/c/src
$ compile base/time/time.cc base/time/time_unittest.cc
...
[0/47] 5.56s S CXX obj/base/base/time.obj
...
[2/3] 9.27s S CXX obj/base/base_unittests/time_unittest.obj
...

Build gn target

GN emits phony target for a gn target label, dropping //-prefix, e.g. base:base for //base:base, which is base target in base/BUILD.gn, so you can use this as a build target.

$ autoninja -C out/Default base:base

Preferred command line flags

If you keep using the same command line flags, you can put it in build/config/siso/.sisorc. It is in .gitignore and not modified by any tool.

In .sisorc, each line specify the command line flags for the siso's subcommand.

e.g.

ninja -k=0 --verbose_failures=0

Then siso ninja or autoninja will use -k=0 --verbose_failures=0 even if you don't specify it on command line. Your command line will be added after the command line flags in .sisorc and later flags are effective.

Limit concurrencies

Siso automatically sets appropriate concurrencies, but if you want to specify them explicitly, you can use the followings

--remote_jobs

--remote_jobs sets maximum number of concurrent remote jobs.

--local_jobs

--local_jobs sets maximum number of concurrent local jobs.

autoninja -j

autoninja sets --remote_jobs from -j if remote is enabled, or sets --local_jobs from -j if remote is disabled and number is not larger than number of cpus.

SISO_LIMITS

You can specify other limits by using SISO_LIMITS environment variables. See SISO_LIMITS documents.

Make sure remote steps works.

Siso may run steps locally even if step can run remotely to make better use of local resources, but it makes it difficult to check how step runs with remote execution.

--strict_remote won't run step locally if it is configured to use remote.

Temporary disable remote.

Use --offline.

Run steps as much as possible.

Siso will stop building if it detects step failure. If you want to run steps as much as possible to see all error messages at once, use -k=0 as Ninja.

If build failed, Siso remembers what targets failed and tried to rebuild the failed targets first to focus on fixing the failure targets with quick iterations. To disable this feature, use -batch or -fast_last_failure=false (available since siso v1.4.11).

Check step's error messages.

Siso records steps output in siso_output files, so you can read it later even if error messages scrolled out.

You can also use --verbose_failures=false to reduce command line in console output.

For AI agents or so, --quiet would be useful.

Rerun steps even if outputs seems to be up-to-date.

Use --clobber.

Siso ignores local modified output files?

Siso makes sure output files are generated by sources, but there are cases that are convenient to modify output files locally and see how build works.

--fs_keep_tainted will keep modified output files.

Use siso other than current release version.

If you want to use different CIPD version than siso_version in DEPS, you can use custom_vars in .gclient.

e.g. To use the latest, non-released version,

solutions = [
 {
    "name": "src",
    "url": "https://chromium.googlesource.com/chromium/src.git",
    ...,
    "custom_vars": {
       "siso_version": "latest",
       ...
    },
 },
]

or to use specific version,

      # Git revision is for https://chromium.googlesource.com/build repo,
      # and the CIPD package for the git revision needs to be exist in
      # https://chrome-infra-packages.appspot.com/p/build/siso
      "siso_version": "git_revision:<git_revision>",

Once you modified .gclient, run gclient sync.

Or if you might want to pin depot_tools version (for autoninja, siso wrapper), checkout specific version of depot_tools, and run update_depot_tools_toggle.py --disable.

If you want to use locally built Siso, Set the siso binary path in environment variable SISO_PATH, so depot_tools/siso use it instead of third_party/siso/cipd/siso.

e.g.

$ export SISO_PATH=$HOME/go/bin/siso