When catching a signal caused by a memory access, print if it's a READ or a WRITE

[kcc]

subj.
This is a subset of #114, but much easier to implement.

[kcc]

http://llvm.org/viewvc/llvm-project?rev=259741&view=rev implements this on linux:

==30107==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 ...
==30107==The signal is caused by a WRITE memory access.

I am asking our Windows and OSX friends to implement this on those platforms.
Once done, please move projects/compiler-rt/test/asan/TestCases/Linux/segv_read_write.c
one level up.

[kcc]

Turns out the code in the change above only works on x86 :)
r259745 disables the feature on other architectures.
Would anyone volunteer for other architectures?

[kcc]

also tracked here: https://code.google.com/p/chromium/issues/detail?id=584336

[rnk]

I think segv_read_write.c will have to stay in TestCases/Posix, since mmap is not available on Windows.

I wrote a similar test using VirtualAlloc in TestCases/Windows and added this functionality on Windows.

[mikea]

I did initial investigation of this on Mac, and I wasn't able to find this information in signal triggering code.

This should be the signal triggering code:

https://github.com/opensource-apple/xnu/blob/10.11/bsd%2Fdev%2Fi386%2Funix_signal.c

[mikea]

Fixed in http://reviews.llvm.org/rL267477

Thanks to Oliver for digging.

[mikea]

Turns out mac support for this works only on intel platform. Arm bug filed: https://llvm.org/bugs/show_bug.cgi?id=27543

[morehouse]

Is there anyone in particular to assign the Arm bug?