Remove dependency from Host to clang.

Host depended on clang because HostInfo had a function to get
the directory where clang was installed.  We move this over to
the clang expression parser plugin where it's more at home.

Differential Revision: https://reviews.llvm.org/D47384

llvm-svn: 333933

4 files changed, 171 insertions, 13 deletions

diff --git a/lldb/source/Plugins/ExpressionParser/Clang/CMakeLists.txt b/lldb/source/Plugins/ExpressionParser/Clang/CMakeLists.txt
index 5e45319091f..ec4f6d5674e 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/CMakeLists.txt
+++ b/lldb/source/Plugins/ExpressionParser/Clang/CMakeLists.txt
@@ -11,6 +11,7 @@ add_lldb_library(lldbPluginExpressionParserClang PLUGIN
   ClangExpressionParser.cpp
   ClangExpressionVariable.cpp
   ClangFunctionCaller.cpp
+  ClangHost.cpp
   ClangModulesDeclVendor.cpp
   ClangPersistentVariables.cpp
   ClangUserExpression.cpp
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangHost.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangHost.cpp
new file mode 100644
index 00000000000..27017df423e
--- /dev/null
+++ b/lldb/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
+#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);
+      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);
+        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);
+  return true;
+}
+
+static bool ComputeClangDirectory(FileSpec &file_spec) {
+  FileSpec lldb_file_spec;
+  if (!HostInfo::GetLLDBPath(lldb::ePathTypeLLDBShlibDir, lldb_file_spec))
+    return false;
+  return ComputeClangDirectory(lldb_file_spec, file_spec, true);
+}
+#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;
+}
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangHost.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangHost.h
new file mode 100644
index 00000000000..4fe423adb1a
--- /dev/null
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangHost.h
@@ -0,0 +1,26 @@
+//===-- ClangHost.h ---------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_PLUGINS_EXPRESSIONPARSER_CLANG_CLANGHOST_H
+#define LLDB_PLUGINS_EXPRESSIONPARSER_CLANG_CLANGHOST_H
+
+namespace lldb_private {
+
+class FileSpec;
+
+#if defined(__APPLE__)
+bool ComputeClangDirectory(FileSpec &lldb_shlib_spec, FileSpec &file_spec,
+                           bool verify);
+#endif
+
+FileSpec GetClangResourceDir();
+
+} // namespace lldb_private
+
+#endif
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangModulesDeclVendor.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangModulesDeclVendor.cpp
index 020f8821f0b..665195f0177 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangModulesDeclVendor.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangModulesDeclVendor.cpp
@@ -25,6 +25,7 @@
 #include "llvm/Support/Threading.h"
 
 // Project includes
+#include "ClangHost.h"
 #include "ClangModulesDeclVendor.h"
 
 #include "lldb/Core/ModuleList.h"
@@ -144,18 +145,6 @@ void StoringDiagnosticConsumer::DumpDiagnostics(Stream &error_stream) {
   }
 }
 
-static FileSpec GetResourceDir() {
-  static FileSpec g_cached_resource_dir;
-
-  static llvm::once_flag g_once_flag;
-
-  llvm::call_once(g_once_flag, []() {
-    HostInfo::GetLLDBPath(lldb::ePathTypeClangDir, g_cached_resource_dir);
-  });
-
-  return g_cached_resource_dir;
-}
-
 ClangModulesDeclVendor::ClangModulesDeclVendor() {}
 
 ClangModulesDeclVendor::~ClangModulesDeclVendor() {}
@@ -610,7 +599,7 @@ ClangModulesDeclVendor::Create(Target &target) {
   }
 
   {
-    FileSpec clang_resource_dir = GetResourceDir();
+    FileSpec clang_resource_dir = GetClangResourceDir();
 
     if (llvm::sys::fs::is_directory(clang_resource_dir.GetPath())) {
       compiler_invocation_arguments.push_back("-resource-dir");