[libc++] Add support for bootstrapping build in libcxx-lit

[hawkinsw]

Summary

Add a [-b|--bootstrap] flag to change cxx-test-depends to
runtimes-test-depends when testing a build of libcxx from bootstrapping.

Signed-off-by: Will Hawkins <[e-mail]>

[hawkinsw]

Hello everyone! It took me a bit to figure out that cxx-test-depends needed to be runtimes-test-depends and where/how to change that when using the libcxx-lit and thought that this little change might help!

[hawkinsw]

Incorrectly marked the patch as libc and not libc++.

[hawkinsw]

@philnik Sorry to bother by adding you as a reviewer. Based on this I thought you might have some input on this little tweak! Thank you for all that you are doing!
Will

[ldionne]

Since we're trying to move away from "runtimes" build and towards using the terminology "bootstapping" build, can we reflect that in the option name? Otherwise this looks like a good idea to me.

[hawkinsw]

In D157045#4566877, @ldionne wrote:

Since we're trying to move away from "runtimes" build and towards using the terminology "bootstapping" build, can we reflect that in the option name? Otherwise this looks like a good idea to me.

Absolutely! Thanks for the review!

[hawkinsw]

Updating to better use bootstrap instead of runtimes based on @ldionne's feedback!

[ldionne]

LGTM. CI issues are unrelated.

libcxx/utils/libcxx-lit

 #!/usr/bin/env bash
 
 set -e
 
 PROGNAME="$(basename "${0}")"
 function usage() {
 cat <<EOF
 Usage:
-${PROGNAME} [-h|--help] <build-directory> [lit options...] tests...
+${PROGNAME} [-h|--help] [-b|--bootstrap] <build-directory> [lit options...] tests...
 
 Shortcut to build the libc++ testing dependencies and run the libc++ tests with Lit.
 
+[-b|--bootstrap]   Configure tests to run against a bootstrap build of libcxx.
 <build-directory>  The path to the build directory to use for building the library.
 [lit options...]   Optional options to pass to 'llvm-lit'.
 tests...           Paths of the tests to run. Those paths are relative to '<monorepo-root>'.
 
 Example
 =======
 $ cmake -S runtimes -B build/ -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi"
 $ libcxx-lit build/ -sv libcxx/test/std/utilities/
 EOF
 }
 
-for arg in $@; do
-    if [[ "${arg}" == "-h" || "${arg}" == "--help" ]]; then
-        usage
-        exit 0
-    fi
-done
+type="cxx"
+if [[ "${1}" == "-h" || "${1}" == "--help" ]]; then
+
+if [[ "${1}" == "-b" || "${1}" == "--bootstrap" ]]; then
+    type="runtimes"
+    shift
+fi
 
 if [[ $# -lt 1 ]]; then
     usage
     exit 1
 fi
 
 build_dir="${1}"
 shift
 
-cmake --build "${build_dir}" --target cxx-test-depends
+if [[ "${type}" == "runtimes" ]]; then
+        echo "N.B.: In a bootstrap build, lit needs a prefix to work correctly;"
+        echo "      See libcxx/docs/Testinglibcxx.rst for more information."
+fi
+cmake --build "${build_dir}" --target ${type}-test-depends
 "${build_dir}/bin/llvm-lit" ${@}