[PATCH] D38858: [cmake] Allow building fuzzers with OSS-Fuzz flags.

[Matt Morehouse via Phabricator via llvm-commits]

morehouse marked an inline comment as done.
morehouse added inline comments.


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Comment at: llvm/cmake/modules/AddLLVM.cmake:897
   cmake_parse_arguments(ARG "" "DUMMY_MAIN" "" ${ARGN})
-  if( LLVM_USE_SANITIZE_COVERAGE )
+  if( LIB_FUZZING_ENGINE )
+    set(LLVM_OPTIONAL_SOURCES ${ARG_DUMMY_MAIN})
----------------
bogner wrote:
> morehouse wrote:
> > bogner wrote:
> > > How / where does this get set?
> > In the CMake configure command.  See https://github.com/google/oss-fuzz/pull/885.
> Okay, if we're going to use a cmake variable for this we should do it right and define a cache variable with documentation in the top level CMakeLists.txt file. I'd probably add it next to where we add LLVM_USE_SANITIZER.
> 
> Also, we should namespace this appropriately. Something like LLVM_LIB_FUZZING_ENGINE or LLVM_FUZZING_ENGINE.
> 
> Optionally, we could also set it up so that we default that to libFuzzer in the LLVM_USE_SANITIZE_COVERAGE case so that we don't even need two cases here.
Regarding switching the configuration under `LLVM_USE_SANITIZE_COVERAGE`, I don't think we want to do that.  OSS-Fuzz uses its own instrumentation which we don't want to mix with `-fsanitize=fuzzer`.  But having `-fsanitize=fuzzer` by default seems helpful for developers.


https://reviews.llvm.org/D38858