v8/test/fuzzer
Michael Achenbach 503e07c3ef Revert "[cleanup] Refactor the Factory"
This reverts commit f9a2e24bbc.

Reason for revert: gc stress failures not all fixed by follow up.

Original change's description:
> [cleanup] Refactor the Factory
> 
> There is no good reason to have the meat of most objects' initialization
> logic in heap.cc, all wrapped by the CALL_HEAP_FUNCTION macro. Instead,
> this CL changes the protocol between Heap and Factory to be AllocateRaw,
> and all object initialization work after (possibly retried) successful
> raw allocation happens in the Factory.
> 
> This saves about 20KB of binary size on x64.
> 
> Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
> Change-Id: Icbfdc4266d7be8b48d2fe085f03411743dc6a0ca
> Reviewed-on: https://chromium-review.googlesource.com/959533
> Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Hannes Payer <hpayer@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#52416}

TBR=jkummerow@chromium.org,yangguo@chromium.org,mstarzinger@chromium.org,hpayer@chromium.org

Change-Id: Idbbc53478742f3e9525eee83342afc6aedae122f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/999414
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52420}
2018-04-06 07:23:19 +00:00
..
json Add json fuzzer 2016-02-02 11:29:01 +00:00
multi_return [turbofan] Add fuzzer to test different signatures for multi-returns 2018-01-12 12:20:27 +00:00
parser Add a library suitable for libfuzzer with a small unit test runner shell 2016-01-26 10:39:03 +00:00
regexp [regexp] add fuzzer support for regexp parser and compiler. 2016-02-01 14:00:38 +00:00
regexp_builtins [regexp] Initial go at a builtins fuzzer 2018-01-18 11:02:57 +00:00
wasm [wasm] Cleanup the wasm fuzzer corpus files. 2017-05-19 09:21:16 +00:00
wasm_async [wasm] Avoid executing infinite loops in the wasm fuzzers 2017-09-07 12:35:45 +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
wasm_data_section [wasm] Write fuzzers for single wasm sections. 2016-09-14 11:17:53 +00:00
wasm_function_sigs_section [wasm] Write fuzzers for single wasm sections. 2016-09-14 11:17:53 +00:00
wasm_globals_section [wasm] Write fuzzers for single wasm sections. 2016-09-14 11:17:53 +00:00
wasm_imports_section [wasm] Write fuzzers for single wasm sections. 2016-09-14 11:17:53 +00:00
wasm_memory_section [wasm] Write fuzzers for single wasm sections. 2016-09-14 11:17:53 +00:00
wasm_names_section [wasm] Write fuzzers for single wasm sections. 2016-09-14 11:17:53 +00:00
wasm_types_section [wasm] Write fuzzers for single wasm sections. 2016-09-14 11:17:53 +00:00
BUILD.gn [build] Add data deps for executable tests 2018-03-26 13:37:03 +00:00
DEPS Add a library suitable for libfuzzer with a small unit test runner shell 2016-01-26 10:39:03 +00:00
fuzzer-support.cc [cleanup] Deprecate EnsureEventLoopInitialized 2018-02-28 15:32:28 +00:00
fuzzer-support.h [fuzzer] Use std::unique_ptr for the FuzzerSupport 2017-11-29 16:36:23 +00:00
fuzzer.cc [test/fuzzer] Fix cpplint complaints 2017-09-04 10:45:21 +00:00
fuzzer.status Add a library suitable for libfuzzer with a small unit test runner shell 2016-01-26 10:39:03 +00:00
json.cc Add GC request to libFuzzers in attempt to avoid parasitic coverage. 2016-04-28 13:32:28 +00:00
multi-return.cc Rename Code::instruction_{start,end,size} functions 2018-04-05 11:39:32 +00:00
parser.cc [test/fuzzer] Fix cpplint complaints 2017-09-04 10:45:21 +00:00
README.md [gyp] move build targets for tests to gypfiles. 2018-01-30 06:31:00 +00:00
regexp-builtins.cc Revert "[cleanup] Refactor the Factory" 2018-04-06 07:23:19 +00:00
regexp.cc Revert "[cleanup] Refactor the Factory" 2018-04-06 07:23:19 +00:00
testcfg.py [wasm] [fuzzer] Remove wasm_call fuzzer 2018-02-01 14:30:49 +00:00
wasm_corpus.tar.gz.sha1 [wasm] Move the wasm fuzzer corpus to a different directory 2017-04-28 23:29:41 +00:00
wasm-async.cc Revert "[cleanup] Refactor the Factory" 2018-04-06 07:23:19 +00:00
wasm-code.cc [test/fuzzer] Fix cpplint complaints 2017-09-04 10:45:21 +00:00
wasm-compile.cc [wasm] [fuzzer] Generate sequences of kWasmStmt 2018-02-02 11:26:06 +00:00
wasm-data-section.cc add gn jumbo build support 2017-08-09 09:05:29 +00:00
wasm-function-sigs-section.cc add gn jumbo build support 2017-08-09 09:05:29 +00:00
wasm-fuzzer-common.cc [fuzzer] Slightly improve generated test cases 2018-03-22 11:53:50 +00:00
wasm-fuzzer-common.h [wasm fuzzer] Require AST fuzzer modules to validate 2017-11-08 21:29:40 +00:00
wasm-globals-section.cc add gn jumbo build support 2017-08-09 09:05:29 +00:00
wasm-imports-section.cc add gn jumbo build support 2017-08-09 09:05:29 +00:00
wasm-memory-section.cc add gn jumbo build support 2017-08-09 09:05:29 +00:00
wasm-names-section.cc add gn jumbo build support 2017-08-09 09:05:29 +00:00
wasm-types-section.cc add gn jumbo build support 2017-08-09 09:05:29 +00:00
wasm.cc Revert "[cleanup] Refactor the Factory" 2018-04-06 07:23:19 +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