1 files changed, 142 insertions, 0 deletions
diff --git a/source/Plugins/ExpressionParser/Clang/ClangHost.cpp b/source/Plugins/ExpressionParser/Clang/ClangHost.cpp
new file mode 100644
index 000000000000..4251d2ee75b9
--- /dev/null
+++ b/source/Plugins/ExpressionParser/Clang/ClangHost.cpp
@@ -0,0 +1,142 @@
+//===-- ClangHost.cpp -------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ClangHost.h"
+
+#include "clang/Basic/Version.h"
+#include "clang/Config/config.h"
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Threading.h"
+
+// Project includes
+#include "lldb/Host/HostInfo.h"
+#if !defined(_WIN32)
+#include "lldb/Host/posix/HostInfoPosix.h"
+#endif
+#include "lldb/Utility/FileSpec.h"
+#include "lldb/Utility/Log.h"
+
+#include <string>
+
+using namespace lldb_private;
+
+#if defined(_WIN32)
+static bool ComputeClangDirectory(FileSpec &file_spec) { return false; }
+#else
+static bool DefaultComputeClangDirectory(FileSpec &file_spec) {
+  return HostInfoPosix::ComputePathRelativeToLibrary(
+      file_spec, (llvm::Twine("/lib") + CLANG_LIBDIR_SUFFIX + "/clang/" +
+                  CLANG_VERSION_STRING)
+                     .str());
+}
+
+#if defined(__APPLE__)
+
+static bool VerifyClangPath(const llvm::Twine &clang_path) {
+  if (llvm::sys::fs::is_directory(clang_path))
+    return true;
+  Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+  if (log)
+    log->Printf("VerifyClangPath(): "
+                "failed to stat clang resource directory at \"%s\"",
+                clang_path.str().c_str());
+  return false;
+}
+
+bool lldb_private::ComputeClangDirectory(FileSpec &lldb_shlib_spec,
+                                         FileSpec &file_spec, bool verify) {
+  std::string raw_path = lldb_shlib_spec.GetPath();
+
+  auto rev_it = llvm::sys::path::rbegin(raw_path);
+  auto r_end = llvm::sys::path::rend(raw_path);
+
+  // Check for a Posix-style build of LLDB.
+  while (rev_it != r_end) {
+    if (*rev_it == "LLDB.framework")
+      break;
+    ++rev_it;
+  }
+
+  if (rev_it == r_end)
+    return DefaultComputeClangDirectory(file_spec);
+
+  // Inside Xcode and in Xcode toolchains LLDB is always in lockstep
+  // with the Swift compiler, so it can reuse its Clang resource
+  // directory. This allows LLDB and the Swift compiler to share the
+  // same Clang module cache.
+  llvm::SmallString<256> clang_path;
+  const char *swift_clang_resource_dir = "usr/lib/swift/clang";
+  auto parent = std::next(rev_it);
+  if (parent != r_end && *parent == "SharedFrameworks") {
+    // This is the top-level LLDB in the Xcode.app bundle.
+    // E.g., "Xcode.app/Contents/SharedFrameworks/LLDB.framework/Versions/A"
+    raw_path.resize(parent - r_end);
+    llvm::sys::path::append(clang_path, raw_path,
+                            "Developer/Toolchains/XcodeDefault.xctoolchain",
+                            swift_clang_resource_dir);
+    if (!verify || VerifyClangPath(clang_path)) {
+      file_spec.SetFile(clang_path.c_str(), true, FileSpec::Style::native);
+      return true;
+    }
+  } else if (parent != r_end && *parent == "PrivateFrameworks" &&
+             std::distance(parent, r_end) > 2) {
+    ++parent;
+    ++parent;
+    if (*parent == "System") {
+      // This is LLDB inside an Xcode toolchain.
+      // E.g., "Xcode.app/Contents/Developer/Toolchains/"               \
+      //       "My.xctoolchain/System/Library/PrivateFrameworks/LLDB.framework"
+      raw_path.resize(parent - r_end);
+      llvm::sys::path::append(clang_path, raw_path, swift_clang_resource_dir);
+      if (!verify || VerifyClangPath(clang_path)) {
+        file_spec.SetFile(clang_path.c_str(), true, FileSpec::Style::native);
+        return true;
+      }
+      raw_path = lldb_shlib_spec.GetPath();
+    }
+    raw_path.resize(rev_it - r_end);
+  } else {
+    raw_path.resize(rev_it - r_end);
+  }
+
+  // Fall back to the Clang resource directory inside the framework.
+  raw_path.append("LLDB.framework/Resources/Clang");
+  file_spec.SetFile(raw_path.c_str(), true, FileSpec::Style::native);
+  return true;
+}
+
+static bool ComputeClangDirectory(FileSpec &file_spec) {
+  if (FileSpec lldb_file_spec = HostInfo::GetShlibDir())
+    return ComputeClangDirectory(lldb_file_spec, file_spec, true);
+  return false;
+}
+#else  // __APPLE__
+
+// All non-Apple posix systems.
+static bool ComputeClangDirectory(FileSpec &file_spec) {
+  return DefaultComputeClangDirectory(file_spec);
+}
+#endif // __APPLE__
+#endif // _WIN32
+
+FileSpec lldb_private::GetClangResourceDir() {
+  static FileSpec g_cached_resource_dir;
+  static llvm::once_flag g_once_flag;
+  llvm::call_once(g_once_flag, []() {
+    ::ComputeClangDirectory(g_cached_resource_dir);
+    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
+    if (log)
+      log->Printf("GetClangResourceDir() => '%s'",
+                  g_cached_resource_dir.GetPath().c_str());
+  });
+  return g_cached_resource_dir;
+}