How to print the coverage report while using libfuzzer with MSVC?

Vishnu Gopalakrishnan 126

While using libfuzzer with MSVC the coverage section is empty. Is there a way to print the coverage report with libfuzzer & MSVC?

Tianyu Sun-MSFT 30,831 Reputation points Microsoft Vendor

2024-10-09T03:56:00.7066667+00:00

Hello @Vishnu Gopalakrishnan ,

Did you check this similar thread: How do I get coverage data from a fuzz test?

Besides, can you confirm that if this issue only appears on Community version of Visual Studio, or it also appears on Enterprise version of Visual Studio?
Tianyu Sun-MSFT 30,831 Reputation points Microsoft Vendor

2024-10-11T07:03:31.9533333+00:00

Hi @Vishnu Gopalakrishnan ,

We have not heard from you for a couple of days. Please let us know if there is anything that we can help here:)
Vishnu Gopalakrishnan 126 Reputation points

2024-10-16T13:24:27.1+00:00

@Tianyu Sun-MSFT Thank you for your reply. The question is exactly what How do I get coverage data from a fuzz test? But I didn't get a proper answer from there.

1 answer

Sergei Kozlov 300 Reputation points

2024-10-09T06:23:08.85+00:00
To print a coverage report while using libFuzzer with MSVC, you can follow these steps:

Install Clang: Ensure you have the Clang compiler installed. You can do this via the Visual Studio Installer by selecting the “C++ Clang Compiler for Windows” and “MSBuild support for LLVM (clang-cl)” components.

Set Up Your Project:

Add the following flags to your compiler and linker settings:
-fsanitize=fuzzer -fsanitize=address -fprofile-instr-generate -fcoverage-mapping
Run Your Fuzz Tests:

Set the environment variable LLVM_PROFILE_FILE to specify the output file for the raw coverage data:

set LLVM_PROFILE_FILE=my_test.profraw

Execute your fuzz tests as usual.
Generate the Coverage Report:

Use llvm-profdata to merge the raw profile data:
llvm-profdata merge -sparse my_test.profraw -o my_test.profdata

Use llvm-cov to generate the coverage report:
llvm-cov show ./your_fuzz_target_binary -instr-profile=my_test.profdata -format=html > coverage_report.html
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Vishnu Gopalakrishnan 126 Reputation points

2024-10-16T13:23:16.8266667+00:00

Thanks Sergei Kozlov. Are you sharing the steps to use with LLVM Clang as the platform toolset. I wish to do it with Visual Studio 2022 as the platform tool set. Is there any option for the same?
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How to print the coverage report while using libfuzzer with MSVC?

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