[Reproducers] Add file provider

This patch adds the file provider which is responsible for capturing
files used by LLDB.

When capturing a reproducer, we use a file collector that is very
similar to the one used in clang. For every file that we touch, we add
an entry with a mapping from its virtual to its real path. When we
decide to generate a reproducer we copy over the files and their
permission into to reproducer folder.

When replaying a reproducer, we load the VFS mapping and instantiate a
RedirectingFileSystem. The latter will transparently use the files
available in the reproducer.

I've tested this on two macOS machines with an artificial example.
Still, it is very likely that I missed some places where we (still) use
native file system calls. I'm hoping to flesh those out while testing
with more advanced examples. However, I will fix those things in
separate patches.

Differential revision: https://reviews.llvm.org/D54617

llvm-svn: 352538

1 files changed, 9 insertions, 6 deletions

diff --git a/lldb/source/Host/macosx/objcxx/Host.mm b/lldb/source/Host/macosx/objcxx/Host.mm
index 7b07f6c5340..3ebfc0c53c4 100644
--- a/lldb/source/Host/macosx/objcxx/Host.mm
+++ b/lldb/source/Host/macosx/objcxx/Host.mm
@@ -1299,12 +1299,15 @@ Status Host::LaunchProcess(ProcessLaunchInfo &launch_info) {
 
   lldb::pid_t pid = LLDB_INVALID_PROCESS_ID;
 
-  if (ShouldLaunchUsingXPC(launch_info)) {
-    error = LaunchProcessXPC(exe_spec.GetPath().c_str(), launch_info, pid);
-  } else {
-    error =
-        LaunchProcessPosixSpawn(exe_spec.GetPath().c_str(), launch_info, pid);
-  }
+  // From now on we'll deal with the external (devirtualized) path.
+  auto exe_path = fs.GetExternalPath(exe_spec);
+  if (!exe_path)
+    return Status(exe_path.getError());
+
+  if (ShouldLaunchUsingXPC(launch_info))
+    error = LaunchProcessXPC(exe_path->c_str(), launch_info, pid);
+  else
+    error = LaunchProcessPosixSpawn(exe_path->c_str(), launch_info, pid);
 
   if (pid != LLDB_INVALID_PROCESS_ID) {
     // If all went well, then set the process ID into the launch info