v8/test/fuzzer
Clemens Backes 3f9ff062b0 Reland "[no-wasm] Exclude src/wasm from compilation"
This is a reland of 80f5dfda01. A condition
in pipeline.cc was inverted, which lead to a CSA verifier error.

Original change's description:
> [no-wasm] Exclude src/wasm from compilation
>
> This is the biggest chunk, including
> - all of src/wasm,
> - torque file for wasm objects,
> - torque file for wasm builtins,
> - wasm builtins,
> - wasm runtime functions,
> - int64 lowering,
> - simd scala lowering,
> - WasmGraphBuilder (TF graph construction for wasm),
> - wasm frame types,
> - wasm interrupts,
> - the JSWasmCall opcode,
> - wasm backing store allocation.
>
> Those components are all recursively entangled, so I found no way to
> split this change up further.
>
> Some includes that were recursively included by wasm headers needed to
> be added explicitly now.
>
> backing-store-unittest.cc is renamed to wasm-backing-store-unittest.cc
> because it only tests wasm backing stores. This file is excluded from
> no-wasm builds then.
>
> R=jkummerow@chromium.org, jgruber@chromium.org, mlippautz@chromium.org, petermarshall@chromium.org
>
> Bug: v8:11238
> Change-Id: I7558f2d12d2dd6c65128c4de7b79173668c80b2b
> Cq-Include-Trybots: luci.v8.try:v8_linux64_no_wasm_compile_rel
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2742955
> Commit-Queue: Clemens Backes <clemensb@chromium.org>
> Reviewed-by: Peter Marshall <petermarshall@chromium.org>
> Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73344}

TBR=jgruber@chromium.org

Bug: v8:11238
Change-Id: I20bd2847a59c68738b5a336cd42582b7b1499585
Cq-Include-Trybots: luci.v8.try:v8_linux64_no_wasm_compile_rel
Cq-Include-Trybots: luci.v8.try:v8_linux_verify_csa_rel_ng
Cq-Include-Trybots: luci.v8.try:v8_linux64_verify_csa_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2752867
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73348}
2021-03-11 14:29:26 +00:00
..
inspector [inspector] Handle isolate termination gracefully 2021-01-19 14:22:41 +00:00
json
multi_return [turbofan] Add fuzzer to test different signatures for multi-returns 2018-01-12 12:20:27 +00:00
parser
regexp
regexp_builtins [regexp] Initial go at a builtins fuzzer 2018-01-18 11:02:57 +00:00
wasm [wasm][fuzzer] Support functions returning i64 2020-09-15 17:23:22 +00:00
wasm_async [wasm][fuzzer] Fix return value of interpreter 2020-08-13 10:08:53 +00:00
wasm_code [wasm] Create a new fuzzer for wasm code. 2016-08-29 13:56:00 +00:00
wasm_compile [wasm] Syntax- and Type-aware Fuzzer 2017-02-17 17:06:29 +00:00
BUILD.gn [no-wasm] Exclude more targets from build 2021-03-09 11:25:54 +00:00
DEPS
fuzzer-support.cc Reland "[no-wasm] Exclude src/wasm from compilation" 2021-03-11 14:29:26 +00:00
fuzzer-support.h [iwyu] Add missing includes of <memory> for std::unique_ptr 2019-09-13 17:13:36 +00:00
fuzzer.cc [test/fuzzer] Fix cpplint complaints 2017-09-04 10:45:21 +00:00
fuzzer.status [no-wasm] Remove wasm tests and fuzzers 2021-02-26 12:53:12 +00:00
inspector-fuzzer.cc [inspector][fuzzer] Allow to overwrite the global 'utils' 2020-12-01 08:57:43 +00:00
json.cc [fuzzer] Fix OOM in v8_json_parser_fuzzer due to unnecessary long input. 2018-07-17 14:25:27 +00:00
multi-return.cc Reland "Reland "[deoptimizer] Change deopt entries into builtins"" 2020-10-21 06:01:38 +00:00
parser.cc [compiler] Fix double error reporting for parser errors 2020-06-10 08:36:41 +00:00
README.md [gyp] move build targets for tests to gypfiles. 2018-01-30 06:31:00 +00:00
regexp-builtins.cc [regexp] Implement the /d flag for RegExp indices 2021-01-26 04:14:10 +00:00
regexp.cc [regexp] Further narrow public API and restrict includes to regexp.h 2019-06-18 12:23:16 +00:00
testcfg.py [inspector][fuzzer] Add inspector fuzzer 2020-11-02 14:29:08 +00:00
wasm_corpus.tar.gz.sha1 [wasm] Update and run script to generate fuzzer corpus 2020-12-01 16:21:51 +00:00
wasm-async.cc [wasm][fuzzer] Fix data race when setting flags 2020-10-05 16:31:11 +00:00
wasm-code.cc [wasm] Move interpreter to test directory 2020-06-23 08:48:14 +00:00
wasm-compile.cc [wasm-simd] Rename vXXXX.all_true to iXXXX.all_true 2021-03-10 00:00:30 +00:00
wasm-fuzzer-common.cc [wasm] Move ValueKind out of ValueType 2021-02-22 10:52:50 +00:00
wasm-fuzzer-common.h [wasm][fuzzer] Fix data race when setting flags 2020-10-05 16:31:11 +00:00
wasm.cc [wasm][fuzzer] Fix data race when setting flags 2020-10-05 16:31:11 +00:00

How to make a libFuzzer fuzzer in V8

This document describes how to make a new libFuzzer fuzzer for V8. A general introduction to libFuzzer can be found here. In short, libFuzzer is an in-process coverage-driven evolutionary fuzzer. libFuzzer serves you with a sequence of byte arrays that you can use to test your code. libFuzzer tries to generate this sequence of byte arrays in a way that maximizes test coverage.

Warning: By itself libFuzzer typically does not generate valid JavaScript code.

Changes to V8

tldr: Do the same as https://codereview.chromium.org/2280623002 to introduce a new fuzzer to V8.

This is a step by step guide on how to make a new fuzzer in V8. In the example the fuzzer is called foo.

  1. Copy one of the existing fuzzer implementations in test/fuzzer/, e.g. cp wasm.cc foo.cc

    • Copying an existing fuzzer is a good idea to get all the required setup, e.g. setting up the isolate
  2. Create a directory called foo in test/fuzzer/ which contains at least one file

    • The file is used by the trybots to check whether the fuzzer actually compiles and runs
  3. Copy the build rules of an existing fuzzer in BUILD.gn, e.g. the build rules for the wasm.cc fuzzer are v8_source_set("wasm_fuzzer") and v8_fuzzer("wasm_fuzzer"). Note that the name has to be the name of the directory created in Step 2 + _fuzzer so that the scripts on the trybots work

  4. Now you can already compile the fuzzer, e.g. with ninja -j 1000 -C out/x64.debug/v8_simple_foo_fuzzer

    • Use this binary to reproduce issues found by cluster fuzz, e.g. out/x64.debug/v8_simple_foo_fuzzer testcase.foo
  5. Copy the binary name and the test directory name in test/fuzzer/fuzzer.isolate

  6. Add the fuzzer to the FuzzerTestSuite in test/fuzzer/testcfg.py

    • This step is needed to run the fuzzer with the files created in Step 2 on the trybots
  7. Commit the changes described above to the V8 repository

Changes to Chromium

tldr: Do the same as https://codereview.chromium.org/2344823002 to add the new fuzzer to cluster fuzz.

  1. Copy the build rules of an existing fuzzer in testing/libfuzzer/fuzzers/BUILD.gn, e.g. the build rule for the wasm.cc fuzzer is v8_wasm_fuzzer. There is no need to set a dictionary , or a seed_corpus. See chromium-fuzzing-getting-started for more information.

  2. Compile the fuzzer in chromium (for different configurations see: https://chromium.googlesource.com/chromium/src/+/master/testing/libfuzzer/reference.md):

    • gn gen out/libfuzzer '--args=use_libfuzzer=true is_asan=true is_debug=false enable_nacl=false'

    • ninja -j 1000 -C out/libfuzzer/ v8_foo_fuzzer

  3. Run the fuzzer locally

    • mkdir /tmp/empty_corpus && out/libfuzzer/v8_foo_fuzzer /tmp/empty_corpus