From fd2876e6a226e144689a15bc3cbc5fe4ac089533 Mon Sep 17 00:00:00 2001 From: KJ Tsanaktsidis Date: Fri, 10 May 2024 10:11:22 +1000 Subject: [PATCH] Update ASAN docs to refer to Clang 18's release Clang 18 has the bugfix we need, so we no longer need to tell people to compile Clang from source. --- doc/contributing/building_ruby.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/doc/contributing/building_ruby.md b/doc/contributing/building_ruby.md index 96cee40cb4..38c78e3cca 100644 --- a/doc/contributing/building_ruby.md +++ b/doc/contributing/building_ruby.md @@ -185,7 +185,7 @@ Using the address sanitizer (ASAN) is a great way to detect memory issues. It ca ``` shell ./autogen.sh mkdir build && cd build -../configure CC=clang cflags="-fsanitize=address -fno-omit-frame-pointer -DUSE_MN_THREADS=0" # and any other options you might like +../configure CC=clang-18 cflags="-fsanitize=address -fno-omit-frame-pointer -DUSE_MN_THREADS=0" # and any other options you might like make ``` The compiled Ruby will now automatically crash with a report and a backtrace if ASAN detects a memory safety issue. To run Ruby's test suite under ASAN, issue the following command. Note that this will take quite a long time (over two hours on my laptop); the `RUBY_TEST_TIMEOUT_SCALE` and `SYNTAX_SUGEST_TIMEOUT` variables are required to make sure tests don't spuriously fail with timeouts when in fact they're just slow. @@ -198,7 +198,7 @@ Please note, however, the following caveats! * ASAN will not work properly on any currently released version of Ruby; the necessary support is currently only present on Ruby's master branch (and the whole test suite passes only as of commit [9d0a5148ae062a0481a4a18fbeb9cfd01dc10428](https://bugs.ruby-lang.org/projects/ruby-master/repository/git/revisions/9d0a5148ae062a0481a4a18fbeb9cfd01dc10428)) * Due to [this bug](https://bugs.ruby-lang.org/issues/20243), Clang generates code for threadlocal variables which doesn't work with M:N threading. Thus, it's necessary to disable M:N threading support at build time for now (with the `-DUSE_MN_THREADS=0` configure argument). -* Currently, ASAN will only work correctly when using a recent head build of LLVM/Clang - it requires [this bugfix](https://github.com/llvm/llvm-project/pull/75290) related to multithreaded `fork`, which is not yet in any released version. See [here](https://llvm.org/docs/CMake.html) for instructions on how to build LLVM/Clang from source (note you will need at least the `clang` and `compiler-rt` projects enabled). Then, you will need to replace `CC=clang` in the instructions with an explicit path to your built Clang binary. +* ASAN will only work when using Clang version 18 or later - it requires [this bugfix](https://github.com/llvm/llvm-project/pull/75290) related to multithreaded `fork`. * ASAN has only been tested so far with Clang on Linux. It may or may not work with other compilers or on other platforms - please file an issue on [https://bugs.ruby-lang.org](https://bugs.ruby-lang.org) if you run into problems with such configurations (or, to report that they actually work properly!) * In particular, although I have not yet tried it, I have reason to believe ASAN will _not_ work properly on macOS yet - the fix for the multithreaded fork issue was actually reverted for macOS (see [here](https://github.com/llvm/llvm-project/commit/2a03854e4ce9bb1bcd79a211063bc63c4657f92c)). Please open an issue on [https://bugs.ruby-lang.org](https://bugs.ruby-lang.org) if this is a problem for you.