aco: Add some useful info to the README for debugging.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12748>

diff --git a/src/amd/compiler/README.md b/src/amd/compiler/README.md
index 8fe2366..4b91a25 100644 (file)
--- a/src/amd/compiler/README.md
+++ b/src/amd/compiler/README.md
@@ -242,6 +242,26 @@ Note that you need to **combine these options into a comma-separated list**, for
 RADV_DEBUG=nocache,shaders ACO_DEBUG=validateir,validatera vkcube
 ```
 
+### Using GCC sanitizers
+
+GCC has several sanitizers which can help figure out hard to diagnose issues. To use these, you need to pass
+the `-Dbsanitize` flag to `meson` when building mesa. For example `-Dbsanitize=undefined` will add support for
+the undefined behavior sanitizer.
+
+### Hardened builds and glibc++ assertions
+
+Several Linux distributions use "hardened" builds meaning several special compiler flags are added by
+downstream packaging which are not used in mesa builds by default. These may be responsible for
+some bug reports of inexplicable crashes with assertion failures you can't reproduce.
+
+Most notable are the glibc++ debug flags, which you can use by adding the `-D_GLIBCXX_ASSERTIONS=1` and
+`-D_GLIBCXX_DEBUG=1` flags.
+
+To see the full list of downstream compiler flags, you can use eg. `rpm --eval "%optflags"`
+on Red Hat based distros like Fedora.
+
+### Good practices
+
 Here are some good practices we learned while debugging visual corruption and hangs.
 
 1. Bisecting shaders: