[debuginfo-tests] Use built lldb for testing if available

The cross-project-tests's debuginfo-tests don't rely on lldb being
built to run. While this is a good, a bug in the system lldb can
cause a test to fail with no way of fixing it. This patch makes it
so the tests use the built lldb instead if it's available.

Author: augusto2112

cross-project-tests/debuginfo-tests/llgdb-tests/llgdb.py

@@ -8,6 +8,14 @@
 # Auto-detect lldb python module.
 import subprocess, platform, os, sys
 
+# Set the path to look first for the built lldb (in case it exists).
+llvm_libs_dir = os.environ["LLVM_LIBS_DIR"]
+built_lldb_path = os.path.join(
+    llvm_libs_dir,
+    f"python{sys.version_info.major}.{sys.version_info.minor}",
+    "site-packages",
+)
+sys.path.insert(0, built_lldb_path)
 try:
     # Just try for LLDB in case PYTHONPATH is already correctly setup.
     import lldb

cross-project-tests/debuginfo-tests/llgdb-tests/test_debuginfo.pl

@@ -56,7 +56,7 @@
 if (!$my_debugger) {
     if ($use_lldb) {
         my $path = dirname(Cwd::abs_path($0));
-        $my_debugger = "/usr/bin/xcrun python3 $path/llgdb.py";
+        $my_debugger = "LLVM_LIBS_DIR=$ENV{'LLVM_LIBS_DIR'} /usr/bin/xcrun python3 $path/llgdb.py";
     } else {
         $my_debugger = "gdb";
     }

cross-project-tests/lit.cfg.py

@@ -37,7 +37,10 @@
 tools = [
     ToolSubst(
         "%test_debuginfo",
-        command=os.path.join(
+        command="LLVM_LIBS_DIR="
+        + config.llvm_libs_dir
+        + " "
+        + os.path.join(
             config.cross_project_tests_src_root,
             "debuginfo-tests",
             "llgdb-tests",