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dawn / dawn / 9854295ff60b96f9c96c2711c55d2562c080dae9
commit9854295ff60b96f9c96c2711c55d2562c080dae9[log] [tgz]
authorRyan Harrison <rharrison@chromium.org>Mon Nov 12 12:20:21 2018 +0000
committerCommit Bot service account <commit-bot@chromium.org>Mon Nov 12 12:20:21 2018 +0000
tree2edb1347898aaae084fd3857ec0c4ad7b3325f88
parent6f86f176a97eaf585493b68c0cfe3e584fdf0afa [diff]
Add fuzzers for SPIRV-Cross

This CL adds in fuzzers for SPIRV-Cross for HLSL, GLSL, and MSL
outputs. These fuzzers live in Dawn because there is not appropriate
location in the Chromium source repo for them and it is unlikely they
would be land-able in the SPIRV-Cross repo, because it is not coupled
with Chromium's build system and thus Clusterfuzz so would be
effectively dead code. Dawn depends on this code, but it is also
integrated into the Chromium build system, so this was the best place
I could find for them

The code under fuzz unfortunately uses exceptions/aborting as its
error reporting mechanism. This is an acknowledge short coming and
there are efforts to remove this behaviour. To work around this and
reduce the number of false positives found by the fuzzers, a signal
trap has been implemented which will be removed once the code under
fuzz has been updated.

The trap replaces the existing signal handler and silencing signals
while running the code under test. This allows the code under test to
call abort() and not crash the fuzzing process. Theoretically, only
SIGABRT should need to be trapped, but something is causing the signal
from abort() to be converted to SIGSEGV when running under ASAN.

This signal trap has been tested with the fuzzing/sanitizers by
intentionally inserting bad calls that will occur after a few thousand
test cases. It was confirmed that the fuzzer detected the issue and
stops fuzzing.

The alternate to implementing this signal trap would be to turn on
exceptions for the fuzzer. This was attempted, but proved to be
fruitless due to what was reported as an ODR issue, but couldn't
couldn't be silenced. The likely underlying issue was a pre-built
library or other object being built without exceptions was causing
different versions of symbols or the exception version of the standard
library not being instrumented by ASAN. Given the majority of Chromium
eco-system turns off exceptions, fixing this issue would not be
helpful to the larger community and was looking like it would require
significant effort.

BUG=chromium:903380

Change-Id: I63a5595383f99b7a0e150d72bb04c89b8d722631
Reviewed-on: https://dawn-review.googlesource.com/c/2260
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Max Moroz <mmoroz@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
13 files changed
tree: 2edb1347898aaae084fd3857ec0c4ad7b3325f88
  1. build_overrides/
  2. examples/
  3. generator/
  4. infra/
  5. scripts/
  6. src/
  7. third_party/
  8. .clang-format
  9. .gitignore
  10. .gn
  11. AUTHORS
  12. BUILD.gn
  13. codereview.settings
  14. CONTRIBUTING.md
  15. dawn.json
  16. DEPS
  17. LICENSE
  18. OWNERS
  19. PRESUBMIT.py
  20. README.chromium
  21. README.md
README.md

Dawn, a WebGPU implementation

Dawn (formerly NXT) is an open-source and cross-platform implementation of the work-in-progress WebGPU standard. It exposes a C/C++ API that maps almost one-to-one to the WebGPU IDL and can be managed as part of a larger system such as a Web browser.

Dawn provides several WebGPU building blocks:

  • WebGPU C/C++ headers that applications and other building blocks use.
  • A “native” implementation of WebGPU using platforms' GPU APIs:
    • D3D12 on Windows 10
    • Metal on OSX (and eventually iOS)
    • Vulkan on Windows, Linux (eventually ChromeOS and Android too)
    • OpenGL as best effort where available
  • A client-server implementation of WebGPU for applications that are in a sandbox without access to native drivers

Directory structure

  • dawn.json: description of the API used to drive code generators.
  • examples: examples showing how Dawn is used.
  • generator: code generator for files produces from dawn.json
    • templates: Jinja2 templates for the generator
  • scripts: scripts to support things like continuous testing, build files, etc.
  • src:
    • common: helper code shared between core Dawn libraries and tests/samples
    • dawn_native: native implementation of WebGPU, one subfolder per backend
    • dawn_wire: client-server implementation of WebGPU
    • include: public headers for Dawn
    • tests: internal Dawn tests
      • end2end: WebGPU tests performing GPU operations
      • unittests: unittests and by extension tests not using the GPU
        • validation: WebGPU validation tests not using the GPU (frontend tests)
    • utils: helper code to use Dawn used by tests and samples
  • third_party: directory where dependencies live as well as their buildfiles.

Building Dawn

Dawn uses the Chromium build system and dependency management so you need to [install depot_tools] and add it to the PATH. Then get the source as follows:

# Clone the repo as "dawn"
git clone https://dawn.googlesource.com/dawn dawn && cd dawn

# Bootstrap the gclient configuration
cp scripts/standalone.gclient .gclient

# Fetch external dependencies and toolchains with gclient
gclient sync

Then generate build files using gn args out/Debug or gn args out/Release. A text editor will appear asking build options, the most common option is is_debug=true/false; otherwise gn args out/Release --list shows all the possible options.

Then use ninja -C out/Release to build dawn and for example ./out/Release/dawn_end2end_tests to run the tests.

Contributing

Please read and follow CONTRIBUTING.md. Dawn doesn‘t have a formal coding style yet, except what’s defined by our clang format style. Overall try to use the same style and convention as code around your change.

If you find issues with Dawn, please feel free to report them on the bug tracker.

License

Please see LICENSE.

Disclaimer

This is not an officially supported Google product.