Clang with Address Sanitizer on Windows fails at link time

I have the following setup:

clang:

clang version 16.0.6
Target: x86_64-pc-windows-msvc
Thread model: posix

windows (not sure if relevant):

Windows 10 Version 22H2 (OS Build 19045.3086)

CMakeLists.txt:

cmake_minimum_required(VERSION 3.22)

project(asan-test C)

add_executable(asan-test)

target_sources(asan-test PRIVATE asan-test.c)
target_compile_options(asan-test PRIVATE -fsanitize=address)
target_link_options(asan-test PRIVATE -fsanitize=address)
target_compile_definitions(asan-test PRIVATE _CRT_SECURE_NO_WARNINGS)

and finally the source code file asan-test.c:

#include <stdio.h>
#include <stdlib.h>

int main()
{
    const int kBufferSize = 255;
    char* buffer = malloc(kBufferSize * sizeof(char));
    FILE* fi = fopen("duck.txt", "r");

    free(buffer);
    fclose(fi);

    return 0;
}

The second command fails at link time:

cmake -S . -B build-windows -D CMAKE_C_COMPILER=clang -G "Unix Makefiles"
cmake --build build-windows

The output contains the following 4 warnings and 1 error:

lld-link: warning: CMakeFiles/asan-test.dir/asan-test.c.obj: locally defined symbol imported: malloc (defined in clang_rt.asan-x86_64.lib(asan_malloc_win.cpp.obj)) [LNK4217]
lld-link: warning: CMakeFiles/asan-test.dir/asan-test.c.obj: locally defined symbol imported: free (defined in clang_rt.asan-x86_64.lib(asan_malloc_win.cpp.obj)) [LNK4217]
lld-link: warning: CMakeFiles/asan-test.dir/asan-test.c.obj: locally defined symbol imported: fclose (defined in libucrt.lib(fclose.obj)) [LNK4217]
lld-link: warning: CMakeFiles/asan-test.dir/asan-test.c.obj: locally defined symbol imported: __stdio_common_vsprintf (defined in libucrt.lib(output.obj)) [LNK4217]

lld-link: error: undefined symbol: __declspec(dllimport) fopen
>>> referenced by <...>\asan-test\asan-test.c:8
>>>               CMakeFiles/asan-test.dir/asan-test.c.obj:(main)

I'm not sure how to approach this problem. I couldn't find anything similar, or maybe I didn't look in the right places.

Solution

I got it working. I came across this page from the Windows port of Address Sanitizer, and the takeaway is that the Windows port...

does not (yet) work with the debug versions of the CRT: /MTd and /MDd
the linker does not accept -fsanitize=address, rather, it needs to link against, for example, clang_rt.asan-x86_64.lib

I changed the setup as follows:

in CMakeLists.txt, I replaced

target_link_options(asan-test PRIVATE -fsanitize=address)

with

target_link_libraries(asan-test PRIVATE clang_rt.asan-x86_64)

in the cmake generation step, I added
```
-D CMAKE_BUILD_TYPE=Release
```