Using AddressSanitizer & ThreadSanitizer In GCC 4.8
Written by Michael Larabel in Compiler on 30 November 2012 at 01:43 PM EST. Add A Comment
While born originally at Google as projects for LLVM, AddressSanitizer and ThreadSanitizer have been ported to GCC and will be part of the forthcoming GCC 4.8 compiler release. Back at Google, they're onto developing MemorySanitizer for LLVM.

AddressSanitizer (ASAN) was developed at Google to be a fast memory error detector. ASAN is capable of finding use-after-free and heap, stack, and global buffer overflow bugs within C and C++ programs. AddressSanitizer was merged into LLVM 3.1 earlier this year and running an ASAN-enabled program leads to only about a 2x slowdown for developers wishing to easily spot these memory errors within their programs. The GCC port of ASAN is currently supported on IA-32, x86-64, and x32 architectures under Linux.

ThreadSanitizer (TSAN) is another newer Google project for detecting data race within C/C++ programs. ThreadSanitizier is based upon the popular Valgrind program and is similar to Helgrind. The slowdown of running a ThreadSanitizier-enabled LLVM program is around 5~15x slower and also requires a run-time library aside from a supported compiler. Within LLVM, ThreadSanitizer is much more primitive and in an alpha state compared to ASAN.

With GCC 4.8, both AddressSanitizer and ThreadSanitizer are available for detecting memory errors and data races, respectively. For tapping AddressSanitizer in GCC, the -fsanitize=address switch must be passed to GCC when building a program. The -fno-omit-frame-pointer switch can also be optionally passed for nicer stack-traces. If you wish to utilize ThreadSanitizer in GCC 4.8, the -fsanitize=thread switch must be thrown, but this port is only working on 64-bit Linux.

Meanwhile, still being developed at Google for LLVM (and presumably ported to GCC too) is MemorySanitizer. MemorySanitizer is intended to spot uninitialized memory reads and shares concepts with Valgrind and Memcheck but uses compile-time instrumentation within LLVM and 1:1 direct shadow memory mapping. MemorySanitizer promises to be much faster than Valgrind (2~3x vs. 20x) for spotting these uninitialized memory reads in C/C++ code-bases. For those interested in more details on MemorySanitizier (MSAN) there is a PDF poster from the talk given earlier this month at the LLVM Developers' Meeting.

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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter or contacted via

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