[sanitizer] Allow dlopen/dlclose interception to be disabled from cmake

[fjricci]

Summary

dlopen and dlclose interception are broken when RUNPATH is used:
https://llvm.org/bugs/show_bug.cgi?id=27790

[filcab]

I think it should be documented somewhere that defining SANITIZER_INTERCEPT_DLOPEN_DLCLOSE allows people to change the default behavior.

[fjricci]

Any suggestions on where to document it? I wasn't able to find documentation for similar defines (ie SANITIZER_INTERCEPT_PRINTF).

[kcc]

LGTM
I don't think we have a place to document this better than the code itself.

[filcab]

Indeed, no good place to document it :-(

Thanks for working on this!

Filipe

compiler-rt/trunk/lib/sanitizer_common/sanitizer_platform_interceptors.h

 #define SANITIZER_INTERCEPT_TSEARCH SI_LINUX_NOT_ANDROID || SI_MAC
 #define SANITIZER_INTERCEPT_LIBIO_INTERNALS SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_FOPEN SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_FOPEN64 SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_OPEN_MEMSTREAM SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_OBSTACK SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_FFLUSH SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_FCLOSE SI_NOT_WINDOWS
+
+#ifndef SANITIZER_INTERCEPT_DLOPEN_DLCLOSE
 #define SANITIZER_INTERCEPT_DLOPEN_DLCLOSE \
     SI_FREEBSD || SI_LINUX_NOT_ANDROID || SI_MAC
+#endif
+
 #define SANITIZER_INTERCEPT_GETPASS SI_LINUX_NOT_ANDROID || SI_MAC
 #define SANITIZER_INTERCEPT_TIMERFD SI_LINUX_NOT_ANDROID
 
 #define SANITIZER_INTERCEPT_MLOCKX SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_FOPENCOOKIE SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_SEM SI_LINUX || SI_FREEBSD
 #define SANITIZER_INTERCEPT_PTHREAD_SETCANCEL SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_MINCORE SI_LINUX