64 lines
2.2 KiB
Text
64 lines
2.2 KiB
Text
This directory contains a few small examples of how the google sanitizers
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can be used to find problems related to memory management and undefined behaviour.
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The sanitizers are libraries that are used to instrument your programs, which is
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done by compiling and linking with the option -fsanitize=<SANITIZER>.
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For building this example includes two makefiles, one for building without
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sanitizers (Makefile) and one for building with them (Makefile.sanitizers).
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Also included is a CMakeListst.txt which uses sanitizers when doing a debug build.
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Examples:
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The file leak.cc contains an example of a memory leak.
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The files bounds.cc, bounds-heap.cc and sum.cc contain examples of accessing
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outside the bounds of an array (on the stack and on the heap).
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The file dangling.cc contains an example of using a dangling pointer.
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The file ub.cc contains an example of undefined behaviour.
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Demonstration:
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First build the programs using Makefile, and run them.
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Then, first do make clean and then build them using Makefile.sanitizers
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(make -f Makefile.sanitizers)
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Run the programs again, and see if the errors are detected. Try to understand
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the diagnostics pringed when the sanitizer detects an error.
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Note that the different sanitizers may produce different error messages
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for the same problem. Compare the output from sum and sum_alt (which are
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built from the same source file, but with different sanitizers.)
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This example also includes a CMakeLists.txt that illustrates how to enable
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the sanitizers for debug builds.
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Building with cmake:
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With cmake, make debug and release builds and compare, typically in
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separate build directories:
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For the release build:
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% mkdir build-rel
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% cd build-rel
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% cmake -DCMAKE_BUILD_TYPE=Release SRC_DIR
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% make
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For the debug build:
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% mkdir build-rel
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% cd build-rel
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% cmake -DCMAKE_BUILD_TYPE=Debug SRC_DIR
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% make
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Both gcc and clang use the google sanitizers, but different compiler versions
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may use different versions of the sanitizers. If you have installed a more recent
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compiler version, you may need to tell cmake to use that.
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By default, cmake will use the system's default compiler. To specify which
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compiler to use, you can add (for gcc)
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-DCMAKE_CXX_COMPILER=g++
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-DCMAKE_C_COMPILER=gcc
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or, for clang:
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-DCMAKE_CXX_COMPILER=clang++
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-DCMAKE_C_COMPILER=clang
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