From: "Andrzej Hunt via GitGitGadget" <gitgitgadget@gmail.com>
To: git@vger.kernel.org
Cc: Josh Steadmon <steadmon@google.com>,
Andrzej Hunt <andrzej@ahunt.org>,
Andrzej Hunt <ajrhunt@google.com>
Subject: [PATCH v2] Update 'make fuzz-all' docs to reflect modern clang
Date: Thu, 04 Mar 2021 15:28:27 +0000 [thread overview]
Message-ID: <pull.889.v2.git.1614871707845.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.889.git.1614514959347.gitgitgadget@gmail.com>
From: Andrzej Hunt <ajrhunt@google.com>
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 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>
---
Update 'make fuzz-all' docs to reflect modern clang
I have updated my patch to:
* Remove -fsanitize-coverage=trace-pc-guard as it is deprecated.
* Add -fsanitize=fuzzer-no-link as per Josh's suggestion.
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-889%2Fahunt%2Ffuzz-docs-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-889/ahunt/fuzz-docs-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/889
Range-diff vs v1:
1: d804b24907fd ! 1: f5b5a11966ca Update 'make fuzz-all' docs to reflect modern clang
@@ Commit message
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 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,
+ (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>
## Makefile ##
@@ Makefile: cover_db_html: cover_db
+# 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" \
+-# CFLAGS="-fsanitize-coverage=trace-pc-guard -fsanitize=address" \
-# LIB_FUZZING_ENGINE=/usr/lib/llvm-4.0/lib/libFuzzer.a \
-+# LIB_FUZZING_ENGINE=-fsanitize=fuzzer \
++# CFLAGS="-fsanitize=fuzzer-no-link,address" \
++# LIB_FUZZING_ENGINE="-fsanitize=fuzzer" \
# fuzz-all
#
FUZZ_CXXFLAGS ?= $(CFLAGS)
Makefile | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/Makefile b/Makefile
index dd08b4ced01c..c7248ac6057b 100644
--- a/Makefile
+++ b/Makefile
@@ -3292,11 +3292,11 @@ cover_db_html: cover_db
# 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)
base-commit: f01623b2c9d14207e497b21ebc6b3ec4afaf4b46
--
gitgitgadget
next prev parent reply other threads:[~2021-03-04 15:29 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-28 12:22 [PATCH] Update 'make fuzz-all' docs to reflect modern clang Andrzej Hunt via GitGitGadget
2021-03-01 22:39 ` Josh Steadmon
2021-03-04 15:26 ` Andrzej Hunt
2021-03-04 15:28 ` Andrzej Hunt via GitGitGadget [this message]
2021-03-04 22:48 ` [PATCH v2] " Junio C Hamano
2021-03-08 17:05 ` Andrzej Hunt
2021-03-08 18:28 ` Junio C Hamano
2021-03-10 18:50 ` Josh Steadmon
2021-03-08 17:14 ` [PATCH v3] Makefile: update " Andrzej Hunt via GitGitGadget
2021-03-10 18:52 ` Josh Steadmon
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