[cfe-dev] Using code coverage in clang-cl.exe

[Reid Kleckner via cfe-dev]

Adding this cflag will not add the clang_rt.profile-*.lib library to the
link line. You would have to figure out the proper name for it (similar to
how we handle ASan) and add it to the build.

In the future, I hope we can simplify compiler-rt's library naming so that
all you have to do is add `-lclangrt_profile` or
`/defaultlib:clangrt_profile` or something like that and it will just work,
instead of having the architecture in the library name.

‪On Fri, May 11, 2018 at 4:30 AM ‫ניצן חדד‬‎ <bhmi12 at gmail.com> wrote:‬

> Hi Reid,
> I just tried compiling chrome-win with -fprofile-instr-generate -Xclang
> -fcoverage-mapping ( I edited the build.gn file in the win toolchain) ,
> and I get link errors.
> I don't see any reason why the feature wouldn't work on windows,I am using
> clang version 7.0.0 (trunk 330570).
>
> These are the errors I received:
> LINK(DLL) common.dll common.dll.lib common.dll.pdb
> FAILED: common.dll common.dll.lib common.dll.pdb
> C:/src/depot_tools/win_tools-2_7_6_bin/python/bin/python.exe
> ../../build/toolchain/win/tool_wrapper.py link-wrapper environment.x64
> False link.exe /nologo /IMPLIB:./common.dll.lib /DLL /OUT:./common.dll
> /PDB:./common.dll.pdb @./common.dll.rsp
> gcm_messages.obj : error LNK2019: unresolved external symbol
> __llvm_profile_runtime referenced in function __llvm_profile_runtime_user
> gcm_messages.obj : error LNK2019: unresolved external symbol
> __llvm_profile_register_function referenced in function
> __llvm_profile_register_functions
> gcm_messages.obj : error LNK2019: unresolved external symbol
> __llvm_profile_register_names_function referenced in function
> __llvm_profile_register_functions
> ./common.dll : fatal error LNK1120: 3 unresolved externals
> [693/29165] CXX
> obj/device/bluetooth/public/mojom/mojom_blink/uuid.mojom-blink.obj
>
>
> ninja: build stopped: subcommand failed.
> Do you have any idea why the chrome build will fail with these flags?
> Thanks,
> Nitzan
>
> 2018-05-11 1:31 GMT+03:00 Reid Kleckner <rnk at google.com>:
>
>> I made these available in clang-cl in r332053. I have no idea if it works
>> on Windows at all, though. In the meantime, you can probably enable this
>> functionality by escaping the flag with -Xclang -fcoverage-mapping.
>>
>> There isn't any particular reason why flags aren't available in clang-cl.
>> We effectively whitelist gcc-style flags one at a time for inclusion in the
>> clang-cl command line interface. At some point I would like to do something
>> like whitelist all -f flags, since they are unlikely to conflict with
>> future MSVC flags.
>>
>
> ‪On Wed, May 9, 2018 at 5:49 PM ‫ניצן חדד via cfe-dev‬‎ <
> cfe-dev at lists.llvm.org> wrote:‬
>
>> Hi awesome community,
>> I am trying to use this feature:
>> https://clang.llvm.org/docs/SourceBasedCodeCoverage.html
>> with clang-cl.exe.
>> I can see in https://clang.llvm.org/docs/UsersManual.html#id8
>> that -fprofile-instr-generate  exists in clang-cl interface but
>> -fcoverage-mapping  doesn't exist, even though it does exist in clang++.
>> Can anyone shed some light on why this feature doesn't exist in clang-cl?
>> it there a plan to future insert it?
>> Thanks,
>> Nitzan.
>>
>>
>> _______________________________________________
>> cfe-dev mailing list
>> cfe-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>
>
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