Configure Linux projects to use Address Sanitizer

In Visual Studio 2019 version 16.1, AddressSanitizer (ASan) support is integrated into Linux projects. You can enable ASan for both MSBuild-based Linux projects and CMake projects. It works on remote Linux systems and on Windows Subsystem for Linux (WSL).

About ASan

ASan is a runtime memory error detector for C/C++ that catches the following errors:

  • Use after free (dangling pointer reference)
  • Heap buffer overflow
  • Stack buffer overflow
  • Use after return
  • Use after scope
  • Initialization order bugs

When ASan detects an error, it stops execution immediately. If you run an ASan-enabled program in the debugger, you see a message that describes the type of error, the memory address, and the location in the source file where the error occurred:

ASan error message

You can also view the full ASan output (including where the corrupted memory was allocated/deallocated) in the Debug pane of the output window.

Enable ASan for MSBuild-based Linux projects

Note

Starting in Visual Studio 2019 version 16.4, AddressSanitizer for Linux projects is enabled via Project properties > Configuration Properties > C/C++ > Enable Address Sanitizer.

To enable ASan for MSBuild-based Linux projects, right-click on the project in Solution Explorer and select Properties. Next, navigate to Configuration Properties > C/C++ > Sanitizers. ASan is enabled via compiler and linker flags, and requires your project to be recompiled to work.

Enable ASan for an MSBuild project

You can pass optional ASan runtime flags by navigating to Configuration Properties > Debugging > AddressSanitizer Runtime Flags. Click the down-arrow to add or remove flags.

Configure ASan runtime flags

Enable ASan for Visual Studio CMake projects

Note

To build with CMake Presets, first enable ASan in your CMakeLists.txt file. For more information, see Enable AddressSanitizer for Windows and Linux.

To enable ASan for CMake, right-click on the CMakeLists.txt file in Solution Explorer and choose CMake Settings for Project.

Make sure you have a Linux configuration (for example, Linux-Debug) selected in the left pane of the dialog:

Screenshot of the left pane with Linux Debug listed as one of the Configuration options.

The ASan options are under General. Enter the ASan runtime flags in the format "flag=value", separated by spaces. The UI incorrectly suggests using semi-colons. Use spaces or colons to separate flags.

Screenshot of the Enable Address Sanitizer option showing some Address Sanitizer run time flags.

Install the ASan debug symbols

To enable the ASan diagnostics, you must install its debug symbols (libasan-dbg) on your remote Linux machine or WSL installation. The version of libasan-dbg that you load depends on the version of GCC installed on your Linux machine:

ASan version GCC version
libasan0 gcc-4.8
libasan2 gcc-5
libasan3 gcc-6
libasan4 gcc-7
libasan5 gcc-8

You can determine which version of GCC you have by using this command:

gcc --version

To view the version of libasan-dbg you need, run your program, and then look at the Debug pane of the Output window. The version of ASan that's loaded corresponds to the version of libasan-dbg needed on your Linux machine. You can use Ctrl + F to search for "libasan" in the window. If you have libasan4, for example, you see a line like this:

Loaded '/usr/lib/x86_64-linux-gnu/libasan.so.4'. Symbols loaded.

You can install the ASan debug bits on Linux distros that use apt with the following command. This command installs version 4:

sudo apt-get install libasan4-dbg

Full instructions for installing debug symbol packages on Ubuntu can be found at Debug symbol packages.

If ASan is enabled, Visual Studio prompts you at the top of the Debug pane of the Output window to install the ASan debug symbols.