[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, 18 insertions, 1 deletions

diff --git a/lldb/source/Initialization/SystemInitializerCommon.cpp b/lldb/source/Initialization/SystemInitializerCommon.cpp
index 2cc3aa8c643..173d48308c6 100644
--- a/lldb/source/Initialization/SystemInitializerCommon.cpp
+++ b/lldb/source/Initialization/SystemInitializerCommon.cpp
@@ -65,6 +65,7 @@ SystemInitializerCommon::Initialize(const InitializerOptions &options) {
   }
 #endif
 
+  // Initialize the reproducer.
   ReproducerMode mode = ReproducerMode::Off;
   if (options.reproducer_capture)
     mode = ReproducerMode::Capture;
@@ -74,7 +75,23 @@ SystemInitializerCommon::Initialize(const InitializerOptions &options) {
   if (auto e = Reproducer::Initialize(mode, FileSpec(options.reproducer_path)))
     return e;
 
-  FileSystem::Initialize();
+  // Initialize the file system.
+  auto &r = repro::Reproducer::Instance();
+  if (repro::Loader *loader = r.GetLoader()) {
+    FileSpec vfs_mapping = loader->GetFile<FileInfo>();
+    if (vfs_mapping) {
+      if (llvm::Error e = FileSystem::Initialize(vfs_mapping))
+        return e;
+    } else {
+      FileSystem::Initialize();
+    }
+  } else if (repro::Generator *g = r.GetGenerator()) {
+    repro::FileProvider &fp = g->GetOrCreate<repro::FileProvider>();
+    FileSystem::Initialize(fp.GetFileCollector());
+  } else {
+    FileSystem::Initialize();
+  }
+
   Log::Initialize();
   HostInfo::Initialize();
   static Timer::Category func_cat(LLVM_PRETTY_FUNCTION);