Update LLVM to v12

Author: Porges

src/ci/dotnet-fuzzing-tools.sh

@@ -20,7 +20,7 @@ mkdir -p $ARTIFACTS/LibFuzzerDotnetLoader
 mkdir -p $ARTIFACTS/sharpfuzz
 
 # Install `libfuzzer-dotnet` pre-reqs.
-sudo apt-get install -y llvm-14 llvm-14-dev clang-14
+sudo apt-get install -y llvm-12 llvm-12-dev clang-12
 
 # Note that dotnet pre-reqs are presumed to be installed
 # by the ci.yml setup (`setup-dotnet` action).

src/runtime-tools/linux/setup.sh

@@ -124,14 +124,14 @@ if type apt > /dev/null 2> /dev/null; then
     done
 
     if ! [ -f ${LLVM_SYMBOLIZER_PATH} ]; then
-        until sudo apt install -y llvm-14; do
+        until sudo apt install -y llvm-12; do
             echo "apt failed, sleeping 10s then retrying"
             sleep 10
         done
 
         # If specifying symbolizer, exe name must be a "known symbolizer".
         # Using `llvm-symbolizer` works for clang 8 .. 10.
-        sudo ln -f -s $(which llvm-symbolizer-14) $LLVM_SYMBOLIZER_PATH
+        sudo ln -f -s $(which llvm-symbolizer-12) $LLVM_SYMBOLIZER_PATH
     fi
 
     # Install dotnet

src/runtime-tools/win64/onefuzz.ps1

@@ -126,7 +126,7 @@ function Install-LLVM {
   log "installing llvm"
   $ProgressPreference = 'SilentlyContinue'
   $exe_path = "llvm-setup.exe"
-  Invoke-WebRequest -uri https://github.com/llvm/llvm-project/releases/download/llvmorg-14.0.6/LLVM-14.0.6-win64.exe -OutFile $exe_path
+  Invoke-WebRequest -uri https://github.com/llvm/llvm-project/releases/download/llvmorg-12.0.1/LLVM-12.0.1-win64.exe -OutFile $exe_path
   cmd /c start /wait $exe_path /S
   $env:Path += ";$env:ProgramFiles\LLVM\bin"
   log "installing llvm: done"