This was very helpful. Turns out one loop decremented using i-- when it
should have had --i. That overwrote element "-1" of a vector, and
caused a later crash. One of the sanitizers caught the out-of-bounds write.
Duncan Murdoch
On 2025-12-10 9:24 a.m., Duncan Murdoch wrote:
Thanks. With any luck, these will show my error, and I can make some
progress.
Duncan Murdoch
On 2025-12-10 7:29 a.m., Prof Brian Ripley wrote:
On 10/12/2025 11:13, Duncan Murdoch wrote:
I am making some large changes to rgl, and something I've done is
causing crashes which I'm having trouble tracking down. These are
likely things that one of the sanitizers could detect, so I'd like to do
a build using one.
The WRE manual gives partial instructions about how to enable them. It
first says to put these lines in ~/.R/Makevars:
CC = gcc -std=gnu99 -fsanitize=address -fno-omit-frame-pointer
CXX = g++ -fsanitize=address -fno-omit-frame-pointer
FC = gfortran -fsanitize=address
Not for macOS ....
These don't work for me on my Mac, generating lots of compile errors
that I don't see with the default settings.
Later WRE gives other instructions for clang 18. What's not clear to me
is what I should do for the default compiler tools (including clang 16)
from mac.r-project.org. Can anyone suggest what I should do for this
situation:
- using the default build of R from CRAN
AFAIK you need to build R with sanitizers: it might be possible without
but the issues often are partially in the way the package calls back into R.
- using the libs and tools from mac.r-project.org
In principle this might needs libs built against the sanitizers but I
have only seen one instance over the years. Normally you will get less
(but still useful) information.
Anything built with sanitizers needs to be of the same compiler version
as used for R (in Linux experience, even the same patch version).
- trying to build rgl with the sanitizer options
See
https://www.stats.ox.ac.uk/pub/bdr/M1-SAN/README.txt
which is tested daily, but only with up-to-date macOS and tools.
I don't think the gfortran used on macOS has sanitizer support, but it
any case GCC's is not compatible with LLVM's. So this is C/C++ only.
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