Siso Development

This document is intended for Siso developers.

Also check go/siso-development (internal).

How to get the code

$ git clone https://chromium.googlesource.com/build
$ cd build/siso

How to build the code

$ go install .

How to test the Siso

$ go test ./...

To enable glog/clog output during tests, use the -args flag to pass glog flags:

$ go test -v ./... -args -logtostderr

Other glog flags can also be passed after -args. See https://pkg.go.dev/github.com/golang/glog for more details.

To build chromium with your Siso,

# in chromium workspace
$ export SISO_PATH=$HOME/go/bin/siso
$ autoninja -C out/Default chrome

How to update proto files.

When modified *.proto, or protobuf version.

$ go generate ./...

How to update module dependencies.

e.g. to update google.golang.org/grpc

$ go get google.golang.org/grpc@v1.M.N
$ go mod tidy

To update protoc-gen-go or protoc-gen-go-grpc, use -tool.

$ go get -tool google.golang.org/protobuf/cmd/protoc-gen-go@v1.M.N
$ go mod tidy
$ go generate ./...

How to modify code with kajiya

When modifying code with kajiya, use go workspace.

At build repo checkout root,

$ go work init siso kajiya

Then, siso will use kajiya code in the checkout, not kajiya specified by go.mod. So, modify code in kajiya and siso.

To land the change,

1. land kajiya change.
2. in siso, run go get go.chromium.org/build/kajiya@latest to update kajiya dependency for siso. check building siso by GOWORK=off go install . and GOWORK=off go test ./...
3. go mod tidy to tidy up go.mod and go.sum.
4. land siso change.

Better to sync dependencies by go work sync and go mod tidy in siso and kajiya.

How to use your favorite IDE

If you opened VS Code to the root of the build repo and you only work on Siso, it's enough to create go workspace by:

$ go work init siso

This should be enough to make suggestions, find definition, etc work.

Profiling

If you call Siso with the flag -pprof_addr=localhost:6060, it will start an HTTP server on this socket that serves runtime profiling data. This is useful for inspecting and debugging various aspects of Siso's performance. Please see the documentation of go tool pprof for instructions and examples how to use it effectively.

Alternatively, you can use -cpuprofile=cpu.prof or -memprofile=memory.prof to collect profiling data and save it to disk.

For using the commands mentioned above, you could add the flags into .sisorc so autoninja is able to pick it up when you build chromium.

Note: If you get an error like Error: could not find file go.chromium.org/build/siso/main.go ... when using the list command in go tool pprof, it means pprof can't find the source files. This often happens if you run go tool pprof from a directory other than the siso source root. Try running go tool pprof from the siso directory.

If that doesn't work, you can fix this by using -source_path to point to your source code and -trim_path to map from the package path.

For example:

go tool pprof -source_path=path/to/build -trim_path=go.chromium.org/build cpu.prof

Tracing

Passing the flag -trace=siso.trace to Siso will cause it captures an execution trace with a wide range of events that can be interpreted by the go tool trace tool. The documentation of go tool trace is a good place to check for ideas how to use this data.