[PATCH] [asan] disable fast unwind on ARM

[Greg Fitzgerald]

> Fast stack unwind should work on ARM for Clang-compiled code, no matter Android or not.
It requires -marm -fno-omit-frame-pointer.

Hmm, I'm not seeing that.  Zooming in on "TestCases/double-free.cc", I see that it is being compiled with -fno-omit-frame-pointer (and -marm is the default for armv7 targets).  I double-checked and recompiled with those flags tacked onto the end of the clang invocation, but the result is the same:

  ==12127==ERROR: AddressSanitizer: attempting double-free on 0x41e007f0 in thread T0:
      #0 0x7269b in free compiler-rt/lib/asan/asan_malloc_linux.cc:65
      #1 0x896e3 in main compiler-rt/test/asan/TestCases/double-free.cc:15
    LLVMSymbolizer: error reading file: No such file or directory.
      #2 0x40a142cb (/lib/arm-linux-gnueabi/libc.so.6+0x182cb)
    
    0x41e007f0 is located 0 bytes inside of 10-byte region [0x41e007f0,0x41e007fa)
    freed by thread T0 here:
      #0 0x7269b in free compiler-rt/lib/asan/asan_malloc_linux.cc:65
    
    previously allocated by thread T0 here:
      #0 0x72859 in malloc compiler-rt/lib/asan/asan_malloc_linux.cc:75
    
    SUMMARY: AddressSanitizer: double-free compiler-rt/lib/asan/asan_malloc_linux.cc:65 free
    ==12127==ABORTING

What am I missing?

http://reviews.llvm.org/D3814