[test-release] fallback to py3's venv module

[bcain]

Summary

If virtualenv is not available, we can look for py3's venv instead. We only use this particular env for installing and running the test suite.

[bcain]

I created this to make it easier to run builds on systems that have python3 but don't have virtualenv installed. python3 comes with venv.

https://docs.python.org/3/library/venv.html says that at one time pyvenv was recommended but that was deprecated in favor of "python3 -m venv" which works very similar to virtualenv.

[bcain]

updated diff w/context

[dim]

LGTM.

[hans]

llvm/utils/release/test-release.sh

309

Should this be inside an if [ $do_test_suite = "yes" ]; ?

I think virtualenv is only used for test_suite.

[bcain]

llvm/utils/release/test-release.sh

309

Should this be inside an if [ $do_test_suite = "yes" ]; ?

I think virtualenv is only used for test_suite.

Yes, that seems right. I will change it.

[hans]

llvm/utils/release/test-release.sh

502

I think this would be a better place to set up ${venv} (more related to test-suite) than in export_sources()

[hans]

lgtm, thanks!

[hans]

Brian: I think this is good to go, right?

llvm/utils/release/test-release.sh

if [ "$System" != "Darwin" -a "$System" != "SunOS" ]; then
   check_program_exists 'chrpath'
 fi
 
 if [ "$System" != "Darwin" ]; then
   check_program_exists 'file'
   check_program_exists 'objdump'
 fi
 
+venv=virtualenv
+if ! type -P 'virtualenv' > /dev/null 2>&1 ; then
+  check_program_exists 'python3'
+  venv="python3 -m venv"
+fi
 check_program_exists ${MAKE}
 
 # Export sources to the build directory.
 function export_sources() {
   SrcDir=$BuildDir/llvm-project
   mkdir -p $SrcDir
   echo "# Using git ref: $git_ref"
 

 ulimit -c 0
 
 if [ "$do_checkout" = "yes" ]; then
     export_sources
 fi
 
 # Setup the test-suite.  Do this early so we can catch failures before
 # we do the full 3 stage build.
 if [ $do_test_suite = "yes" ]; then
   SandboxDir="$BuildDir/sandbox"
   Lit=$SandboxDir/bin/lit
   TestSuiteBuildDir="$BuildDir/test-suite-build"
   TestSuiteSrcDir="$BuildDir/llvm-test-suite"
 
-  virtualenv $SandboxDir
+  ${venv} $SandboxDir
   $SandboxDir/bin/python $BuildDir/llvm-project/llvm/utils/lit/setup.py install
   mkdir -p $TestSuiteBuildDir
 fi
 
 (
 Flavors="Release"
 if [ "$do_debug" = "yes" ]; then
     Flavors="Debug $Flavors"