sphinx-doc: update documentation (#2072)

* sphinx-doc: update documentation

The Sphinx documentation is not up to date. We no longer use LLVM 15.x
but rather LLVM 18.x

Furthermore, it's easier to just use the provided helper script.

Signed-off-by: David Korczynski <david@adalogics.com>

* refine instructions

Signed-off-by: David Korczynski <david@adalogics.com>

* avoid reading the filesystem if were local

Signed-off-by: David Korczynski <david@adalogics.com>

---------

Signed-off-by: David Korczynski <david@adalogics.com>

doc/sphinx/source/installation-instructions/installation.rst

@@ -7,9 +7,11 @@ Clone latest Fuzz Introspector and create virtual environment
 
     git clone --recurse-submodules https://github.com/ossf/fuzz-introspector
     cd fuzz-introspector
-    python3 -m virtualenv .venv
+    python3.11 -m virtualenv .venv
     . .venv/bin/activate
-    pip3 install -r requirements.txt
+    cd src
+    python3 -m pip install .
+    cd ../
 
 At this point you can test Fuzz Introspector with different frontends depending
 on the type of language you want to analyse:
@@ -27,48 +29,15 @@ C/C++
 Fuzz-introspector relies on an LTO LLVM pass and this requires us to build a
 custom Clang where the LTO pass is part of the compiler tool chain.
 Additionally, we rely on the Gold linker, which means we need to build this too,
-which comes as part of the binutils project. The next step is, therefore, to
-do to this:
+which comes as part of the binutils project. To install these things and patch
+LLVM with our pass, we have a wrapper script for building/installing:
 
 .. code-block:: bash
 
-    mkdir build
-    cd build
-
-    # Build binutils
-    apt install texinfo
-    git clone --depth 1 git://sourceware.org/git/binutils-gdb.git binutils
-    mkdir build
-    cd ./build
-    ../binutils/configure --enable-gold --enable-plugins --disable-werror
-    make all-gold
-    cd ../
-
-    # Build LLVM and Clang
-    git clone https://github.com/llvm/llvm-project/
-    cd llvm-project/
-    git checkout release/15.x
-
-    # Patch Clang to run fuzz introspector
-    ../../frontends/llvm/patch-llvm.sh
-    cp -rf ../../frontends/llvm/include/llvm/Transforms/FuzzIntrospector/ \
-           ./llvm/include/llvm/Transforms/FuzzIntrospector
-    cp -rf ../../frontends/llvm/lib/Transforms/FuzzIntrospector \
-           ./llvm/lib/Transforms/FuzzIntrospector
-    cd ../
-
-    # Build LLVM and clang
-    mkdir llvm-build
-    cd llvm-build
-    cmake -G "Unix Makefiles" -DLLVM_ENABLE_PROJECTS="clang;compiler-rt"  \
-          -DCMAKE_BUILD_TYPE=Debug \
-          -DLLVM_BINUTILS_INCDIR=../binutils/include \
-          -DLLVM_TARGETS_TO_BUILD="X86" ../llvm-project/llvm/
-    make llvm-headers
-    make
+   ./build_all.sh
 
-We now have the LLVM frontend build and this will be used to extract data
-about the software we analyse.
+Running the above script, we now have the LLVM frontend build and this will be
+used to extract data about the software we analyse.
 
 Option 1: only static analysis
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -80,17 +49,14 @@ Build a test case
     # From the root of the fuzz-introspector repository
     cd tests/simple-example-0
 
-    # Run compiler pass to generate *.data and *.data.yaml files
-    mkdir work
-    cd work
-    FUZZ_INTROSPECTOR=1 ../../../build/llvm-build/bin/clang -fsanitize=fuzzer \
-      -fuse-ld=gold -flto -g ../fuzzer.c -o fuzzer
+    # Build the target using Fuzz Introspector instrumentation
+    ./build_all.sh
 
     # Run post-processing to analyse data files and generate HTML report
-    python3 ../../../src/main.py correlate --binaries_dir=.
+    python3 ../../../src/main.py correlate --binaries-dir=.
     python3 ../../../src/main.py report \
-      --target_dir=. \
-      --correlation_file=./exe_to_fuzz_introspector_logs.yaml
+      --target-dir=. \
+      --correlation-file=./exe_to_fuzz_introspector_logs.yaml
 
     # The post-processing will have generated various .html, .js, .css and .png fies,
     # and these are accessible in the current folder. Simply start a webserver and 
@@ -120,10 +86,10 @@ This is option 2.
       -fuse-ld=gold -flto -g ../fuzzer.c -o fuzzer
 
     # Run post-processing to analyse data files and generate HTML report
-    python3 ../../../src/main.py correlate --binaries_dir=.
+    python3 ../../../src/main.py correlate --binaries-dir=.
     python3 ../../../src/main.py report \
-      --target_dir=. \
-      --correlation_file=./exe_to_fuzz_introspector_logs.yaml
+      --target-dir=. \
+      --correlation-file=./exe_to_fuzz_introspector_logs.yaml
 
     # The post-processing will have generated various .html, .js, .css and .png fies,
     # and these are accessible in the current folder. Simply start a webserver and

src/fuzz_introspector/analysis.py

@@ -1129,6 +1129,10 @@ def _extract_test_information_cpp(report_dict, out_dir):
 
     directories = set()
 
+    # If this is run locally and not in OSS-Fuzz, let's skip for now.
+    if not os.path.isdir('/src/'):
+        return directories
+
     # All directories added
     for path in normalized_paths:
         if path.startswith('/usr/'):