Makefile: update 'make fuzz-all' docs to reflect modern clang
Clang no longer produces a libFuzzer.a. Instead, you can include
libFuzzer by using -fsanitize=fuzzer. Therefore we should use that in
the example command for building fuzzers.
We also add -fsanitize=fuzzer-no-link to the CFLAGS to ensure that all
the required instrumentation is added when compiling git [1], and remove
-fsanitize-coverage=trace-pc-guard as it is deprecated.
I happen to have tested with LLVM 11 - however -fsanitize=fuzzer appears
to work in a wide range of reasonably modern clangs.
(On my system: what used to be libFuzzer.a now lives under the following
path, which is tricky albeit not impossible for a novice such as myself
to find:
/usr/lib64/clang/11.0.0/lib/linux/libclang_rt.fuzzer-x86_64.a )
[1] https://releases.llvm.org/11.0.0/docs/LibFuzzer.html#fuzzer-usage
Signed-off-by: Andrzej Hunt <ajrhunt@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Makefile b/Makefile
index dfb0f10..f3dc217 100644
--- a/Makefile
+++ b/Makefile
@@ -3299,11 +3299,11 @@
# are not necessarily appropriate for general builds, and that vary greatly
# depending on the compiler version used.
#
-# An example command to build against libFuzzer from LLVM 4.0.0:
+# An example command to build against libFuzzer from LLVM 11.0.0:
#
# make CC=clang CXX=clang++ \
-# CFLAGS="-fsanitize-coverage=trace-pc-guard -fsanitize=address" \
-# LIB_FUZZING_ENGINE=/usr/lib/llvm-4.0/lib/libFuzzer.a \
+# CFLAGS="-fsanitize=fuzzer-no-link,address" \
+# LIB_FUZZING_ENGINE="-fsanitize=fuzzer" \
# fuzz-all
#
FUZZ_CXXFLAGS ?= $(CFLAGS)
