Add extra_compiler_files attribute to make ignorelist files available to sanitizers during compilation

[lalten]

I'm adding sanitizers into our build and I need the compilation action to have access to the sanitizer blacklist.

# In MODULE.bazel
llvm.toolchain(
    name = "llvm_toolchain",
    (...)
    extra_compiler_files = "@@//tools/sanitizers:compiletime_ignorelist.txt",
)

# In .bazelrc
build:sanitizers --copt -fsanitize-ignorelist=tools/sanitizers/compiletime_ignorelist.txt

The compiletime_ignorelist.txt is a https://releases.llvm.org/17.0.1/tools/clang/docs/SanitizerSpecialCaseList.html

I'd like to hear feedback if you think this is a good idea, maybe there are better alternatives?

[siddharthab]

Thanks for the contribution.

[myrrc]

Hey @lalten. Does this work with legacy non-MODULE builds? I've tried integrating it into our codebase, but having this file in project root, bazel complains about

ERROR: no such package '@@llvm_toolchain//sanitizer_ignore.txt': BUILD file not found in directory 'sanitizer_ignore.txt' of external repository @@llvm_toolchain. Add a BUILD file to a directory to mark it as a package.
ERROR: /home/myrrc/.cache/bazel/_bazel_myrrc/7a4fea5dac5e95bf5e0bf58faa801eff/external/llvm_toolchain/BUILD.bazel:114:10: no such package '@@llvm_toolchain//sanitizer_ignore.txt': BUILD file not found in directory 'sanitizer_ignore.txt' of external repository @@llvm_toolchain. Add a BUILD file to a directory to mark it as a package. and referenced by '@@llvm_toolchain//:compiler-components-x86_64-linux'

i.e. it tries to find the file in the external repository rather than in the project.

Specifying the repository explicitly e.g. @@myrepo//:sanitizer_ignore.txt leads to a loop.

[lalten]

Hey @lalten. Does this work with legacy non-MODULE builds? I've tried integrating it into our codebase, but having this file in project root, bazel complains about

ERROR: no such package '@@llvm_toolchain//sanitizer_ignore.txt': BUILD file not found in directory 'sanitizer_ignore.txt' of external repository @@llvm_toolchain. Add a BUILD file to a directory to mark it as a package.
ERROR: /home/myrrc/.cache/bazel/_bazel_myrrc/7a4fea5dac5e95bf5e0bf58faa801eff/external/llvm_toolchain/BUILD.bazel:114:10: no such package '@@llvm_toolchain//sanitizer_ignore.txt': BUILD file not found in directory 'sanitizer_ignore.txt' of external repository @@llvm_toolchain. Add a BUILD file to a directory to mark it as a package. and referenced by '@@llvm_toolchain//:compiler-components-x86_64-linux'

i.e. it tries to find the file in the external repository rather than in the project.

Specifying the repository explicitly e.g. @@myrepo//:sanitizer_ignore.txt leads to a loop.

I have not tried using this on WORKSPACE :/
Did you find a solution?

[myrrc]

Did you find a solution?

Unfortunately, no, our SDO team promised to have a look. We'll possibly just patch the file inside the toolchain itself