diff mbox series

[v3] Makefile: update 'make fuzz-all' docs to reflect modern clang

Message ID pull.889.v3.git.1615223682911.gitgitgadget@gmail.com (mailing list archive)
State Accepted
Commit e82816998ff1b9228a968a8513bfb58198ecdbb1
Headers show
Series [v3] Makefile: update 'make fuzz-all' docs to reflect modern clang | expand

Commit Message

Andrzej Hunt March 8, 2021, 5:14 p.m. UTC
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 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>
---
    Update 'make fuzz-all' docs to reflect modern clang
    
    This version of the patch fixes the commit message as per Junio's
    feedback. Thank you!

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-889%2Fahunt%2Ffuzz-docs-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-889/ahunt/fuzz-docs-v3
Pull-Request: https://github.com/gitgitgadget/git/pull/889

Range-diff vs v2:

 1:  f5b5a11966ca ! 1:  bc0d8b615410 Update 'make fuzz-all' docs to reflect modern clang
     @@ Metadata
      Author: Andrzej Hunt <ajrhunt@google.com>
      
       ## Commit message ##
     -    Update 'make fuzz-all' docs to reflect modern clang
     +    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.
     +    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
     +    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.
     +    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:
     +    (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


 Makefile | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)


base-commit: be7935ed8bff19f481b033d0d242c5d5f239ed50

Comments

Josh Steadmon March 10, 2021, 6:52 p.m. UTC | #1
On 2021.03.08 17:14, Andrzej Hunt via GitGitGadget wrote:
> 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 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>
> ---
>     Update 'make fuzz-all' docs to reflect modern clang
>     
>     This version of the patch fixes the commit message as per Junio's
>     feedback. Thank you!
> 
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-889%2Fahunt%2Ffuzz-docs-v3
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-889/ahunt/fuzz-docs-v3
> Pull-Request: https://github.com/gitgitgadget/git/pull/889
> 
> Range-diff vs v2:
> 
>  1:  f5b5a11966ca ! 1:  bc0d8b615410 Update 'make fuzz-all' docs to reflect modern clang
>      @@ Metadata
>       Author: Andrzej Hunt <ajrhunt@google.com>
>       
>        ## Commit message ##
>      -    Update 'make fuzz-all' docs to reflect modern clang
>      +    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.
>      +    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
>      +    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.
>      +    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:
>      +    (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
> 
> 
>  Makefile | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index dfb0f1000fa3..f3dc2178324e 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -3299,11 +3299,11 @@ 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: be7935ed8bff19f481b033d0d242c5d5f239ed50
> -- 
> gitgitgadget

This version looks good to me, although you may also want to make the
changes Junio suggested regarding LIB_FUZZING_ENGINE.

Thanks!
diff mbox series

Patch

diff --git a/Makefile b/Makefile
index dfb0f1000fa3..f3dc2178324e 100644
--- a/Makefile
+++ b/Makefile
@@ -3299,11 +3299,11 @@  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)