Instrumented libraries for dynamic tools

Instrumented libraries are a part of Chromium's development infrastructure. They are intended to complement sanitizer tools (AddressSanitizer, MemorySanitizer, ThreadSanitizer).

Only Ubuntu Trusty x86_64 is supported at this time.

Overview

Sanitizer tools rely on compile-time instrumentation. However, Chromium code may call into system-installed third-party shared libraries, which were not built with the appropriate instrumentation. This is a problem:

• bugs in third-party libraries, which may affect Chromium, go undetected,
• certain Chromium bugs may go undetected (e.g. passing an invalid buffer to third-party code),
• MemorySanitizer generates lots of bogus reports, which makes it unusable. This happens because MSan doesn't recognize any memory initialization which happens in uninstrumented code.

To avoid this issue, we've made it possible to make Chromium use sanitizer-instrumented versions of third-party DSOs. By setting a GN flag, you can either have them built from source during Chromium build, or download pre-built binaries from Google Storage. The list contains ~50 third-party packages, which should cover most of the DSO dependencies of Chrome and tests (enough at least to run MSan without bogus reports).

Using pre-built binaries

Follow the MemorySanitizer instructions.

Note that we don't provide pre-built binaries for every configuration. At this point in time only MSan is supported, with msan_track_origins either 0 or 2.

Building from source

Instructions for rebuilding instrumented libraries.

Adding new packages

You'll need to ping earthdok@ or glider@ to do this. The information below is for reference.

To add a new package, you need to do the following:

• get OSS compliance approval,
• add a new target to third_party/instrumented_libraries/BUILD.gn,
• add the package to third_party/instrumented_libs/scripts/install-build-deps.sh,
• make sure it builds and works on Focal (i.e. where applicable),
• update the pre-built binaries.

Usually you want to use the same configure flags that debian/rules uses.

To rebuild the binaries, follow the instructions for Building from source.