llvm dev - Jul 2017 - Where does the LLVM implement the Ubsan's instrumentations?

Hello,
I'm investigating on enabling the Ubsan in my firmware. I have two questions
about Ubsan:
1.            I see the Ubsan run-time lib functions are defined in
http://llvm.org/svn/llvm-project/compiler-rt/trunk/lib/ubsan/ubsan_interface.inc,
but I cannot find how the LLVM implement the Ubsan instrumentations. I see the
Asan's instrumentation lib is in
http://llvm.org/svn/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp,
but where is the Ubsan instrumentation lib?
2.            My firmware usage scenario is quite sensitive to the code size.
Does the Ubsan have the build option to use callbacks instead of inline code for
the Ubsan instrumentations (like Asan's
-asan-instrumentation-with-call-threshold=0) ?

Thanks
Steven
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20170721/207ec3fa/attachment.html>

Most of UBSan runs in the late parts of Clang, see the lib/CodeGen 
directory.
> 2.            My firmware usage scenario is quite sensitive to the code 
> size. Does the Ubsan have the build option to use callbacks instead of 
> inline code for the Ubsan instrumentations (like Asan's 
> -asan-instrumentation-with-call-threshold=0) ?
I think your best bet for controlling code bloat is to compile with 
-fsanitize=undefined -fsanitize-trap=undefined.

John

> I think your best bet for controlling code bloat is to compile with 
> -fsanitize=undefined -fsanitize-trap=undefined.
Also you may not need all of UBSan's checks at the same time -- so pick 
and choose among its checks using the finer-grained flags.

If you're really stuck against a hard limit on code size, try applying 
UBSan to a subset of files in your project at a time.

John