В Thu, 16 May 2024 21:32:24 +0200 David Cortes <david.cortes.riv...@gmail.com> пишет:
> Unfortunately, after some further testing, it seems this was just a > matter of getting lucky - using the alternative non-STRUCT_SUBTYPES > def. of Altrep still leads to memory corruptions and crashes, just at > different points than when using the STRUCT_SUBTYPES definition. So much for the hope for an easy solution. > May I ask: how would you go around getting R code into Godbolt? Definitely not much of it. I was assuming that the problem was due to passing structs by value (something that had been a problem for MSVC compatibility more than a decade ago on x86 Windows), so I only provided typedef struct SEXPREC *SEXP, one of the two definitions of R_altrep_class_t and related macros, declared a number of functions that would accept or return R_altrep_class_t by value, and tried to call them. I don't know a good way to use Godbolt for larger amounts of code. > As far as I can tell, the altrep methods are calling the functions > which they were assigned so at least the 'set' and 'dataptr' methods > are working, but memory corruptions that crash the program happen > after calling such altrep methods, particularly when there is a > combination of 'R_UnwindProtect', C++ 'catch' that involves > destructing variables before 'R_ContinueUnwind', and then 'Rf_error'. What do the crashes look like? Is it heap corruption? Stack corruption? Are they at least deterministic? Can you reproduce the error by compiling one of the example ALTREP classes [1] with MSVC, without C++ exception handling? What about using R_ContinueUnwind() and/or C++ exceptions in some non-ALTREP code compiled using MSVC? Maybe if you run the code under Dr. Memory [2] or Application Verifier [3], it'll detect the corruption slightly earlier and let you pinpoint the problem? I'm assuming that there is no good way to link a sanitizer into the process. Can you eliminate C runtime incompatibility? Is there a chance that a heap object allocated by the UCRT linked to R is freed by the CRT linked to the MSVC-side library (or vice versa)? -- Best regards, Ivan [1] https://github.com/altrep-examples [2] https://drmemory.org/ [3] https://learn.microsoft.com/en-us/windows-hardware/drivers/devtest/application-verifier ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
