The FIDL toolchain is composed of roughly three parts:
fidlc.fidl filesThe front-end lives at //zircon/tools/fidl/, with tests in //zircon/system/utest/fidl/.
The back-end and runtime library locations are based on the target:
TBD: linter, formatter, gidl, difl, regen scripts, etc.
This is a crowdsourced section from the FIDL team on useful tools that they use for working on the FIDL codebase.
Most of the FIDL team uses VSCode for development. Some useful plugins and workflows:
The remote ssh feature works really well for doing remote work from your laptop.
The Fuchsia documentation has instructions for setting up language servers:
The rewrap extension is useful for automatically reflowing lines to a certain length (e.g. when editing markdown files).
To get automatic syntax highlighting for the bindings golden files, update the file.associations setting:
"files.associations": { "*.test.json.golden": "json", "*.test.json.rs.golden": "rust", "*.test.json.cc.golden": "cpp", "*.test.json.h.golden": "cpp", "*.test.json.llcpp.cc.golden": "cpp", "*.test.json.llcpp.h.golden": "cpp", "*.test.json.go.golden": "go", "*.test.json_async.dart.golden": "dart", "*.test.json_test.dart.golden": "dart" },
We follow the Fuchsia C++ Style Guide, with additional rules to further remove ambiguity around the application or interpretation of guidelines.
Always place the initializer list on a line below the constructor.
// Don't do this. SomeClass::SomeClass() : field_(1), another_field_(2) {} // Correct. SomeClass::SomeClass() : field_(1), another_field_(2) {}
Comments must respect 80 columns line size limit, unlike code which can extend to 100 lines size limit.
[&]”).Seeing [&] is a strong signal that the lambda exists within the current scope only, and can be used to distinguish local from non-local lambdas.
// Correct. std::set<const flat::Library*, LibraryComparator> dependencies; auto add_dependency = [&](const flat::Library* dep_library) { if (!dep_library->HasAttribute("Internal")) { dependencies.insert(dep_library); } };
Read the Fuchsia Getting Started guide first.
If you are working on the FIDL toolchain, use:
fx set core.x64 --with //bundles/fidl:tests
If you are working on an LSC:
fx set terminal.x64 --with //bundles:kitchen_sink \ --with //topaz/packages/tests:all \ --with //sdk:modular_testing
To symbolize backtraces, you'll need a symbolizer in scope:
export ASAN_SYMBOLIZER_PATH="$FUCHSIA_DIR/prebuilt/third_party/clang/$HOST_PLATFORM/bin/llvm-symbolizer"
We provide mostly one-liners to run tests for the various parts. When in doubt, refer to the “Test:” comment in the git commit message; we do our best to describe the commands used to validate our work there.
# optional; builds fidlc for the host with ASan <https://github.com/google/sanitizers/wiki/AddressSanitizer> fx set core.x64 --variant=host_asan # build fidlc fx build zircon/tools
If you're doing extensive edit-compile-test cycles on fidlc, building with no optimizations can make a significant difference in the build speed. To optimize the build, change the opt_level setting in zircon/public/gn/config/levels.gni. But be careful: the kernel is not regularly tested with opt_level below 2, and it does not support -1 at all (this setting can cause kernel panics from stack overflows in the kernel).
To avoid accidentally committing this change, run:
git update-index --skip-worktree zircon/public/gn/config/levels.gni
If you want to allow the changes to be committed again, run:
git update-index --no-skip-worktree zircon/public/gn/config/levels.gni
fidlc tests are at:
To build and run fidlc tests:
fx build system/utest:host $FUCHSIA_DIR/out/default.zircon/host-x64-linux-clang/obj/system/utest/fidl-compiler/fidl-compiler-test.debug
To run a specific test case, use the --case flag:
fx build system/utest:host $FUCHSIA_DIR/out/default.zircon/host-x64-linux-clang/obj/system/utest/fidl-compiler/fidl-compiler-test.debug -- --case attributes_tests
Alternatively, it is faster to invoke ninja targets directly:
ninja -C out/default.zircon \ host-x64-linux-clang/obj/tools/fidl/fidlc \ host-x64-linux-clang/obj/system/utest/fidl-compiler/fidl-compiler-test ./out/default.zircon/host-x64-linux-clang/obj/system/utest/fidl-compiler/fidl-compiler-test.debug
Build and run fidl-coding-tables tests:
Note: --with-base puts all zircon tests in /boot with the bringup.x64 target, or /system when you the core.x64 target.
fx set bringup.x64 --with-base //garnet/packages/tests:zircon # optionally append "--variant asan" fx build fx qemu -k -c zircon.autorun.boot=/boot/bin/runtests+-t+fidl-coding-tables-test >>>>>>> 6a061a72892... [fidl] Direct ninja targets for fidlc workflow
To regenerate the FIDL definitions used in unit testing, run:
fx build zircon/tools $FUCHSIA_DIR/out/default.zircon/tools/fidlc \ --tables $FUCHSIA_DIR/zircon/system/utest/fidl/fidl/extra_messages.cc \ --files $FUCHSIA_DIR/zircon/system/utest/fidl/fidl/extra_messages.test.fidl
To regenerate the fidlc JSON goldens, ensure fidlc is built and up to date, then run:
fx exec $FUCHSIA_DIR/zircon/tools/fidl/testdata/regen.sh
These “golden” files are examples of what kind of JSON IR fidlc produces and are used to track changes. It is required to regenerate the golden files each time the JSON IR is changed in any way, otherwise the json_generator_tests fails.
Build:
fx build garnet/go/src/fidl
Run:
$FUCHSIA_DIR/out/default/host_x64/fidlgen
Some example tests you can run:
fx run-host-tests fidlgen_hlcpp_test fx run-host-tests fidlgen_golang_ir_test
To regenerate the goldens:
fx exec garnet/go/src/fidl/compiler/backend/typestest/regen.sh
Build:
fx ninja -C out/default host_x64/fidlgen_dart
Run:
$FUCHSIA_DIR/out/default/host_x64/fidlgen_dart
Some example tests you can run:
fx run-host-tests fidlgen_dart_backend_test
To regenerate the goldens:
fx exec topaz/bin/fidlgen_dart/regen.sh
You first need to have Fuchsia running in an emulator. Here are the steps:
Tab 1> fx build && fx serve-updates Tab 2> fx qemu -kN Tab 3> fx test fidl-c-tests
The -k flag enables KVM. It is not required, but the emulator is much slower without it. The -N flag enables networking.
There is one test that must be run separately as a zbi test, which is the fidl-test:
fx qemu -kN -c zircon.autorun.boot=/boot/bin/runtests+-t+fidl-test
When the test completes, you're running in the QEMU emulator. To exit, use Ctrl-A x.
Alternatively, if you build including the shell you can run these commands from the shell:
Tab 1> fx set core.x64 --with-base //garnet/packages/tests:zircon Tab 1> fx build && fx qemu -kN Tab 2> fx shell Tab 2(shell)> runtests -t fidl-test
Some of the C runtime tests can run on host:
fx build zircon && fx run-host-tests fidl-test
This only includes a few tests, so be sure to check the output to see if it is running the test you care about.
You first need to have Fuchsia running in an emulator. Here are the steps:
Tab 1> fx build && fx serve-updates Tab 2> fx qemu -kN Tab 3> fx test fidl_tests
There are separate tests for LLCPP that can be run in the same way as fidl_tests:
You first need to have Fuchsia running in an emulator. Here are the steps:
Tab 1> fx build && fx serve-updates Tab 2> fx qemu -kN Tab 3> fx test go_fidl_tests fidl_go_conformance
As with normal Go tests, you can pass various flags to control execution, filter test cases, run benchmarks, etc. For instance:
Tab 3> fx test go_fidl_tests -- -test.v -test.run 'TestAllSuccessCases/.*union.*'
An example invocation that gets CPU and memory profiles from a benchmark might look like:
Tab 3> fx test -R bench -o go_fidl_tests -- -test.run=- -test.bench=. -test.cpuprofile=/data/cpuprofile -test.memprofile=/data/memprofile
To get the data off of the device under test, we can use the realm name (the argument to the -R flag we passed above) to look for the data on disk.
Tab 3> fx scp "[$(fx get-device-addr)]:/data/r/sys/r/bench/fuchsia.com:go_fidl_tests:0#meta:go_extended_fidl_test.cmx/cpuprofile" out/cpuprofile
To view the profile data, you can use pprof.
Tab 3> go tool pprof -http:8080 out/cpuprofile
You first need to have Fuchsia running in an emulator. Here are the steps:
Tab 1> fx build && fx serve-updates Tab 2> fx qemu -kN Tab 3> fx test rust_fidl_tests
The Dart FIDL bindings tests are in //topaz/bin/fidl_bindings_test/.
You first need to have Fuchsia running in an emulator. Here are the steps:
Tab 1> fx build && fx serve-updates Tab 2> fx qemu -kN Tab 3> fx test fidl_bindings_test
Details about how the compatibility tests work and where the code is located can be found in the README at //garnet/bin/fidl_compatibility_test
To run the compatibility tests, you first need to have Fuchsia running in an emulator:
Tab 1> fx build && fx serve Tab 2> fx qemu -kN
To run the compatibility tests with HLCPP, LLCPP, Rust, and Go:
Tab 3> fx set core.x64 --with-base //garnet/packages/tests:zircon --with //garnet/packages/tests:all Tab 3> fx test fidl_compatibility_test
To run the compatibility tests with Dart:
Tab 3> fx set core.x64 --with //topaz/packages/tests:all Tab 3> fx test fidl_compatibility_test_topaz
To rebuild GIDL:
fx build host-tools/gidl
fx set core.x64 --with //tools/fidl/measure-tape:host fx build
| Name | Test Command | Coverage |
|---|---|---|
| gidl parser | fx run-host-tests gidl_parser_test | tools/fidl/gidl/parser |
| fidlgen type definitions | fx run-host-tests fidlgen_types_test | garnet/go/src/fidl/compiler/backend/types |
| fidlgen hlcpp | fx run-host-tests fidlgen_hlcpp_test | garnet/go/src/fidl/compiler/hlcpp_backend |
| fidlgen llcpp | fx run-host-tests fidlgen_llcpp_test | garnet/go/src/fidl/compiler/llcpp_backend |
| fidlgen golang | fx run-host-tests fidlgen_golang_test | garnet/go/src/fidl/compiler/backend/golang |
| fidlgen rust | fx test fidlgen_rust_test | tools/fidl/fidlgen_rust |
| fidlgen syzkaller | fx run-host-tests fidlgen_syzkaller_test | garnet/go/src/fidl/compiler/backend/syzkaller |
| fidlgen dart | fx run-host-tests fidlgen_dart_backend_test | topaz/bin/fidlgen_dart |
| fidl c runtime host test | fx run-host-tests fidl-test | zircon/system/ulib/fidl |
| c++ host unittests | fx run-host-tests fidl_cpp_host_unittests | sdk/lib/fidl |
| c++ bindings tests | fx test fidl_tests | sdk/lib/fidl |
| llcpp bindings tests | fx test fidl_llcpp_types_test | garnet/go/src/fidl/compiler/llcpp_backend |
| go bindings tests | fx test go_fidl_tests | third_party/go/syscall/zx/fidl third_party/go/syscall/zx/fidl/fidl_test |
| dart bindings tests | fx test fidl_bindings_test | topaz/public/dart/fidl |
| rust bindings | fx test rust_fidl_tests | src/lib/fidl/rust/fidl |
| transformer host tests | fx run-host-tests fidl_transformer_host_tests | zircon/system/ulib/fidl/transformer.cc |
| transformer tests | fx run-host-tests fidl_tests | zircon/system/ulib/fidl/transformer.cc |
| measure tape test | fx test measure-tape-tests | //tools/fidl/measure-tape |
The following requires: fx set bringup.x64 --with-base //garnet/packages/tests:zircon
| Name | Test Command | Directories Covered |
|---|---|---|
| fidlc host test | $FUCHSIA_DIR/out/default.zircon/host-x64-linux-clang/obj/system/utest/fidl-compiler/fidl-compiler-test.debug | zircon/system/host/fidl |
| fidl c runtime test | fx qemu -k -c zircon.autorun.boot=/boot/bin/runtests+-t+fidl-test | zircon/system/ulib/fidl |
| fidl c runtime test | fx qemu -k -c zircon.autorun.boot=/boot/bin/runtests+-t+fidl-simple-test | zircon/system/ulib/fidl |
| fidl c-llcpp interop test | fx qemu -k -c zircon.autorun.boot=/boot/bin/runtests+-t+fidl-llcpp-interop-test | zircon/system/ulib/fidl |
Benchmarks can either be run directly or through one of two test runners: fuchsia_benchmarks (old), SL4F (new).
Benchmarks on chromeperf are currently generated through the fuchsia_benchmarks runner but are transitioning to SL4F. During this transition, benchmarks should be integrated in both systems.
Ensure that the benchmarks are included in your build:
fx set core.x64 --with=//src/tests/benchmarks
You will need to fx build and restart qemu for the packages to be available.
Available benchmarks:
| Name | Benchmark Command | Notes |
|---|---|---|
| Go Benchmarks | fx shell /bin/go_fidl_microbenchmarks | |
| Rust Benchmarks | fx shell /bin/rust_fidl_microbenchmarks /tmp/myresultsfile | Results can be viewed with fx shell cat /tmp/myresultsfile/ |
| LLCPP benchmarks | fx shell /bin/llcpp_fidl_microbenchmarks | |
| lib/fidl Benchmarks | fx shell /bin/lib_fidl_microbenchmarks | |
| Roundtrip Benchmarks | fx shell /bin/roundtrip_fidl_benchmarks |
Ensure that the benchmarks are included in your build:
fx set core.x64 --with=//src/tests/benchmarks
You will need to fx build and restart qemu for the packages to be available.
First, a directory needs to be created for the test results:
fx shell mkdir /tmp/results
Then you can run the benchmarks:
fx shell /bin/fuchsia_benchmarks /tmp/results
In addition to FIDL benchmarks, many other fuchsia benchmarks will run.
SL4F requires the terminal.x64 product. Use fx set to switch products:
fx set terminal.x64
To run all FIDL tests, use:
fx run-e2e-tests fidl_microbenchmarks_test
To test a specific binding, add the -n [binding] flag. For example:
fx run-e2e-test fidl_microbenchmarks_test -- -n "rust_fidl_microbenchmarks"
| Name | Regen Commands | Input | Output |
|---|---|---|---|
| fidlc goldens | fx exec $FUCHSIA_DIR/zircon/tools/fidl/testdata/regen.sh | zircon/tools/fidl/testdata | zircon/tools/fidl/goldens |
| fidlgen goldens | fx exec $FUCHSIA_DIR/garnet/go/src/fidl/compiler/backend/typestest/regen.sh | zircon/tools/fidl/goldens | garnet/go/src/fidl/compiler/backend/goldens |
| dart fidlgen goldens | fx exec $FUCHSIA_DIR/topaz/bin/fidlgen_dart/regen.sh | zircon/tools/fidl/goldens | topaz/bin/fidlgen_dart/goldens |
| dangerous identifiers | garnet/tests/fidl-dangerous-identifiers/generate.py | garnet/tests/fidl-dangerous-identifiers/dangerous_identifiers.txt | garnet/tests/fidl-dangerous-identifiers/cpp/ garnet/tests/fidl-dangerous-identifiers/fidl/ |
| regen third party go | fx exec $FUCHSIA_DIR/third_party/go/regen-fidl | ||
| fidldoc goldens | REGENERATE_GOLDENS_FOLDER=$FOLDER fx test fidldoc_bin_test --golden_test | $FOLDER |
ninjaIn some cases, GN can build many unneeded targets. You can build a specific target with ninja instead of GN. In most cases, you can grep for the binary name to determine the ninja invocation.
For example, you can grep for fidlgen_dart:
fx ninja -C out/default -t targets all | grep -e 'fidlgen_dart:'
This example outputs a list of ninja targets which includes host_x64/fidlgen_dart. Therefore, to build fidlgen_dart run the following ninja command:
fx ninja -C out/default host_x64/fidlgen_dart
There are several ways of debugging issues in host binaries. This section gives instructions for the example case where fidlc --files test.fidl is crashing:
Note: Even with all optimizations turned off, the binaries in out/default/host_x64 are stripped. For debugging, you should use the binaries with the .debug suffix, such as out/default.zircon/host-x64-linux-clang/obj/tools/fidl/fidlc.debug.
Start GDB:
gdb --args out/default.zircon/host-x64-linux-clang/obj/tools/fidl/fidlc.debug --files test.fidl
Then, enter “r” to start the program.
Ensure you are compiling with ASan enabled:
fx set core.x64 --variant=host_asan fx build host_x64/fidlc
Then run out/default/host_x64/fidlc --files test.fidl. That binary should be the same as out/default.zircon/host-x64-linux-asan/obj/tools/fidl/fidlc.
On Google Linux machines, you may need to install a standard version of Valgrind instead of using the pre-installed binary:
sudo apt-get install valgrind
Then:
valgrind -v -- out/default.zircon/host-x64-linux-clang/obj/tools/fidl/fidlc.debug --files test.fidl
One common task is to evolve the language, or introduce stricter checks in fidlc. These changes typically follow a three phase approach:
fidlc;fidlc to compile all layers, including vendor/google, make changes as needed;fidlc changes can finally be merged.All of this assumes that (a) code which wouldn't pass the new checks, or (b) code that has new features, is not introduced concurrently between step 2 and step 3. That typically is the case, however, it is ok to deal with breaking rollers once in a while.
To update all the saved fidlgen files, run the following command, which automatically searches for and generates the necessary go files:
fx exec third_party/go/regen-fidl
TBD
TBD
We'd actually like all back-ends to be in separate tools!
Down the road, we plan to have a script over all the various tools (fidlc, fidlfmt, the various back-ends) to make all things accessible easily, and manage the chaining of these things. For instance, it should be possible to generate Go bindings in one command such as:
fidl gen --library my_library.fidl --binding go --out-dir go/src/my/library
Or format a library in place with:
fidl fmt --library my_library.fidl -i