tests: finally fix up test-fuzz-targets.t

It's been failing on my workstation for a while, since I have a new enough
LLVM that I had the fuzzer goo, but not so new that I actually had
FuzzedDataProvider. This is a better solution all around in my opinion.

I _believe_ this should let us run these tests on most systems, even
those using GCC instead of clang. That said, my one attempt to test
this on my macOS laptop failed miserably, and I don't feel like doing
more work on this right now.

Differential Revision: https://phab.mercurial-scm.org/D7566

contrib/fuzz/Makefile

@@ -1,190 +1,190
 CC = clang
 CXX = clang++
 
 # By default, use our own standalone_fuzz_target_runner.
 # This runner does no fuzzing, but simply executes the inputs
 # provided via parameters.
 # Run e.g. "make all LIB_FUZZING_ENGINE=/path/to/libFuzzer.a"
 # to link the fuzzer(s) against a real fuzzing engine.
 #
 # OSS-Fuzz will define its own value for LIB_FUZZING_ENGINE.
 LIB_FUZZING_ENGINE ?= standalone_fuzz_target_runner.o
 
 PYTHON_CONFIG ?= $$OUT/sanpy/bin/python-config
 
 CXXFLAGS += -Wno-deprecated-register
 
-all: bdiff mpatch xdiff
+all: standalone_fuzz_target_runner.o oss-fuzz
 
 standalone_fuzz_target_runner.o: standalone_fuzz_target_runner.cc
 
 pyutil.o: pyutil.cc pyutil.h
 	$(CXX) $(CXXFLAGS) -g -O1 \
 	  `$(PYTHON_CONFIG) --cflags` \
 	  -I../../mercurial -c -o pyutil.o pyutil.cc
 
 bdiff.o: ../../mercurial/bdiff.c
 	$(CC) $(CFLAGS) -fsanitize=fuzzer-no-link,address -c -o bdiff.o \
 	  ../../mercurial/bdiff.c
 
 bdiff: bdiff.cc bdiff.o 
 	$(CXX) $(CXXFLAGS) -DHG_FUZZER_INCLUDE_MAIN=1 -g -O1 -fsanitize=fuzzer-no-link,address \
 	  -std=c++17 \
 	  -I../../mercurial bdiff.cc bdiff.o -o bdiff
 
 bdiff-oss-fuzz.o: ../../mercurial/bdiff.c
 	$(CC) $(CFLAGS) -c -o bdiff-oss-fuzz.o ../../mercurial/bdiff.c
 
 bdiff_fuzzer: bdiff.cc bdiff-oss-fuzz.o
 	$(CXX) $(CXXFLAGS) -std=c++17 -I../../mercurial bdiff.cc \
 	  bdiff-oss-fuzz.o $(LIB_FUZZING_ENGINE) -o \
 	  $$OUT/bdiff_fuzzer
 
 mpatch.o: ../../mercurial/mpatch.c
 	$(CC) -g -O1 -fsanitize=fuzzer-no-link,address -c -o mpatch.o \
 	  ../../mercurial/mpatch.c
 
 mpatch: CXXFLAGS += -std=c++17
 mpatch: mpatch.cc mpatch.o
 	$(CXX) $(CXXFLAGS) -DHG_FUZZER_INCLUDE_MAIN=1 -g -O1 -fsanitize=fuzzer-no-link,address \
 	  -I../../mercurial mpatch.cc mpatch.o -o mpatch
 
 mpatch-oss-fuzz.o: ../../mercurial/mpatch.c
 	$(CC) $(CFLAGS) -c -o mpatch-oss-fuzz.o ../../mercurial/mpatch.c
 
 mpatch_fuzzer: mpatch.cc mpatch-oss-fuzz.o 
 	$(CXX) $(CXXFLAGS) -std=c++17 -I../../mercurial mpatch.cc \
 	  mpatch-oss-fuzz.o $(LIB_FUZZING_ENGINE) -o \
 	  $$OUT/mpatch_fuzzer
 
 mpatch_corpus.zip:
 	python mpatch_corpus.py $$OUT/mpatch_fuzzer_seed_corpus.zip
 
 x%.o: ../../mercurial/thirdparty/xdiff/x%.c ../../mercurial/thirdparty/xdiff/*.h
 	$(CC) -g -O1 -fsanitize=fuzzer-no-link,address -c \
 	  -o $@ \
 	  $<
 
 xdiff: CXXFLAGS += -std=c++17
 xdiff: xdiff.cc xdiffi.o xprepare.o xutils.o 
 	$(CXX) $(CXXFLAGS) -DHG_FUZZER_INCLUDE_MAIN=1 -g -O1 -fsanitize=fuzzer-no-link,address \
 	  -I../../mercurial xdiff.cc \
 	  xdiffi.o xprepare.o xutils.o -o xdiff
 
 fuzz-x%.o: ../../mercurial/thirdparty/xdiff/x%.c ../../mercurial/thirdparty/xdiff/*.h
 	$(CC) $(CFLAGS) -c \
 	  -o $@ \
 	  $<
 
 xdiff_fuzzer: xdiff.cc fuzz-xdiffi.o fuzz-xprepare.o fuzz-xutils.o 
 	$(CXX) $(CXXFLAGS) -std=c++17 -I../../mercurial xdiff.cc \
 	  fuzz-xdiffi.o fuzz-xprepare.o fuzz-xutils.o \
 	  $(LIB_FUZZING_ENGINE) -o $$OUT/xdiff_fuzzer
 
 manifest.o: ../../mercurial/cext/manifest.c
 	$(CC) $(CFLAGS) `$(PYTHON_CONFIG) --cflags` \
 	  -I../../mercurial \
 	  -c -o manifest.o ../../mercurial/cext/manifest.c
 
 charencode.o: ../../mercurial/cext/charencode.c
 	$(CC) $(CFLAGS) `$(PYTHON_CONFIG) --cflags` \
 	  -I../../mercurial \
 	  -c -o charencode.o ../../mercurial/cext/charencode.c
 
 parsers.o: ../../mercurial/cext/parsers.c
 	$(CC) $(CFLAGS) `$(PYTHON_CONFIG) --cflags` \
 	  -I../../mercurial \
 	  -c -o parsers.o ../../mercurial/cext/parsers.c
 
 dirs.o: ../../mercurial/cext/dirs.c
 	$(CC) $(CFLAGS) `$(PYTHON_CONFIG) --cflags` \
 	  -I../../mercurial \
 	  -c -o dirs.o ../../mercurial/cext/dirs.c
 
 pathencode.o: ../../mercurial/cext/pathencode.c
 	$(CC) $(CFLAGS) `$(PYTHON_CONFIG) --cflags` \
 	  -I../../mercurial \
 	  -c -o pathencode.o ../../mercurial/cext/pathencode.c
 
 revlog.o: ../../mercurial/cext/revlog.c
 	$(CC) $(CFLAGS) `$(PYTHON_CONFIG) --cflags` \
 	  -I../../mercurial \
 	  -c -o revlog.o ../../mercurial/cext/revlog.c
 
 dirs_fuzzer: dirs.cc manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o
 	$(CXX) $(CXXFLAGS) `$(PYTHON_CONFIG) --cflags` \
 	  -Wno-register -Wno-macro-redefined \
 	  -I../../mercurial dirs.cc \
 	  manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o \
 	  $(LIB_FUZZING_ENGINE) `$(PYTHON_CONFIG) --ldflags` \
 	  -o $$OUT/dirs_fuzzer
 
 fncache_fuzzer: fncache.cc manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o
 	$(CXX) $(CXXFLAGS) `$(PYTHON_CONFIG) --cflags` \
 	  -Wno-register -Wno-macro-redefined \
 	  -I../../mercurial fncache.cc \
 	  manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o \
 	  $(LIB_FUZZING_ENGINE) `$(PYTHON_CONFIG) --ldflags` \
 	  -o $$OUT/fncache_fuzzer
 
 jsonescapeu8fast_fuzzer: jsonescapeu8fast.cc manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o
 	$(CXX) $(CXXFLAGS) `$(PYTHON_CONFIG) --cflags` \
 	  -Wno-register -Wno-macro-redefined \
 	  -I../../mercurial jsonescapeu8fast.cc \
 	  manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o \
 	  $(LIB_FUZZING_ENGINE) `$(PYTHON_CONFIG) --ldflags` \
 	  -o $$OUT/jsonescapeu8fast_fuzzer
 
 manifest_corpus.zip:
 	python manifest_corpus.py $$OUT/manifest_fuzzer_seed_corpus.zip
 
 manifest_fuzzer: manifest.cc manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o
 	$(CXX) $(CXXFLAGS) `$(PYTHON_CONFIG) --cflags` \
 	  -Wno-register -Wno-macro-redefined \
 	  -I../../mercurial manifest.cc \
 	  manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o \
 	  $(LIB_FUZZING_ENGINE) `$(PYTHON_CONFIG) --ldflags` \
 	  -o $$OUT/manifest_fuzzer
 
 revlog_fuzzer: revlog.cc manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o
 	$(CXX) $(CXXFLAGS) `$(PYTHON_CONFIG) --cflags` \
 	  -Wno-register -Wno-macro-redefined \
 	  -I../../mercurial revlog.cc \
 	  manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o \
 	  $(LIB_FUZZING_ENGINE) `$(PYTHON_CONFIG) --ldflags` \
 	  -o $$OUT/revlog_fuzzer
 
 revlog_corpus.zip:
 	python revlog_corpus.py $$OUT/revlog_fuzzer_seed_corpus.zip
 
 dirstate_fuzzer: dirstate.cc manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o
 	$(CXX) $(CXXFLAGS) `$(PYTHON_CONFIG) --cflags` \
 	  -Wno-register -Wno-macro-redefined \
 	  -I../../mercurial dirstate.cc \
 	  manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o \
 	  $(LIB_FUZZING_ENGINE) `$(PYTHON_CONFIG) --ldflags` \
 	  -o $$OUT/dirstate_fuzzer
 
 dirstate_corpus.zip:
 	python dirstate_corpus.py $$OUT/dirstate_fuzzer_seed_corpus.zip
 
 fm1readmarkers_fuzzer: fm1readmarkers.cc manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o
 	$(CXX) $(CXXFLAGS) `$(PYTHON_CONFIG) --cflags` \
 	  -Wno-register -Wno-macro-redefined \
 	  -I../../mercurial fm1readmarkers.cc \
 	  manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o pyutil.o \
 	  $(LIB_FUZZING_ENGINE) `$(PYTHON_CONFIG) --ldflags` \
 	  -o $$OUT/fm1readmarkers_fuzzer
 
 fm1readmarkers_corpus.zip:
 	python fm1readmarkers_corpus.py $$OUT/fm1readmarkers_fuzzer_seed_corpus.zip
 
 clean:
 	$(RM) *.o *_fuzzer \
 	  bdiff \
 	  mpatch \
 	  xdiff
 
 oss-fuzz: bdiff_fuzzer mpatch_fuzzer mpatch_corpus.zip xdiff_fuzzer dirs_fuzzer fncache_fuzzer jsonescapeu8fast_fuzzer manifest_fuzzer manifest_corpus.zip revlog_fuzzer revlog_corpus.zip dirstate_fuzzer dirstate_corpus.zip fm1readmarkers_fuzzer fm1readmarkers_corpus.zip
 
 .PHONY: all clean oss-fuzz

tests/test-fuzz-targets.t

@@ -1,46 +1,64
 #require test-repo
 
   $ cd $TESTDIR/../contrib/fuzz
+  $ OUT=$TESTTMP ; export OUT
 
 which(1) could exit nonzero, but that's fine because we'll still end
 up without a valid executable, so we don't need to check $? here.
 
   $ if which gmake >/dev/null 2>&1; then
   >     MAKE=gmake
   > else
   >     MAKE=make
   > fi
 
   $ havefuzz() {
   >     cat > $TESTTMP/dummy.cc <<EOF
   > #include <stdlib.h>
   > #include <stdint.h>
   > int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) { return 0; }
   > int main(int argc, char **argv) {
   >     const char data[] = "asdf";
   >     return LLVMFuzzerTestOneInput((const uint8_t *)data, 4);
   > }
   > EOF
   >     $CXX $TESTTMP/dummy.cc -o $TESTTMP/dummy \
   >        -fsanitize=fuzzer-no-link,address || return 1
   > }
 
 #if clang-libfuzzer
   $ CXX=clang++ havefuzz || exit 80
-  $ $MAKE -s clean all
+  $ $MAKE -s clean all PYTHON_CONFIG=`which python-config`
 #endif
 #if no-clang-libfuzzer clang-6.0
   $ CXX=clang++-6.0 havefuzz || exit 80
-  $ $MAKE -s clean all CC=clang-6.0 CXX=clang++-6.0
+  $ $MAKE -s clean all CC=clang-6.0 CXX=clang++-6.0 PYTHON_CONFIG=`which python-config`
 #endif
 #if no-clang-libfuzzer no-clang-6.0
   $ exit 80
 #endif
 
-Just run the fuzzers for five seconds each to verify it works at all.
-  $ ./bdiff -max_total_time 5
-  $ ./mpatch -max_total_time 5
-  $ ./xdiff -max_total_time 5
+  $ cd $TESTTMP
+
+Run each fuzzer using dummy.cc as a fake input, to make sure it runs
+at all. In the future we should instead unpack the corpus for each
+fuzzer and use that instead.
+
+  $ for fuzzer in `ls *_fuzzer | sort` ; do
+  >   echo run $fuzzer...
+  >   ./$fuzzer dummy.cc > /dev/null 2>&1 
+  > done
+  run bdiff_fuzzer...
+  run dirs_fuzzer...
+  run dirstate_fuzzer...
+  run fm1readmarkers_fuzzer...
+  run fncache_fuzzer...
+  run jsonescapeu8fast_fuzzer...
+  run manifest_fuzzer...
+  run mpatch_fuzzer...
+  run revlog_fuzzer...
+  run xdiff_fuzzer...
 
 Clean up.
+  $ cd $TESTDIR/../contrib/fuzz
   $ $MAKE -s clean