Add documentation about potential fuzzing pitfall

Change-Id: I2ea01b3ad3359510bff3ffd298d4ed17d3677ffc
Reviewed-by: David Neto <>
Reviewed-by: dan sinclair <>
diff --git a/ b/
index 86a0b50..32f4620 100644
--- a/
+++ b/
@@ -16,6 +16,7 @@
  * `TINT_BUILD_WGSL_READER` : enable the WGSL input reader (on by default)
  * `TINT_BUILD_SPV_WRITER` : enable the SPIR-V output writer (on by default)
  * `TINT_BUILD_WGSL_WRITER` : enable the WGSL output writer (on by default)
+ * `TINT_BUILD_FUZZERS` : enable building fuzzzers (off by default)
 ## Building
 Tint uses Chromium dependency management so you need to install [depot_tools]
@@ -52,6 +53,20 @@
 make # -j N for N-way parallel build
+### Fuzzers on MacOS
+If you are attempting fuzz, using `TINT_BUILD_FUZZERS=ON`, the version of llvm
+in the XCode SDK does not have the needed libfuzzer functionality included.
+The build error that you will see from using the XCode SDK will look something
+like this:
+ld: file not found:/Applications/
+The solution to this problem is to use a full version llvm, like what you would
+get via homebrew, `brew install llvm`, and use something like `CC=<path to full
+clang> cmake ..` to setup a build using that toolchain.
 ## Issues
 Please file any issues or feature requests at