Enable clangDriver in project.cc

https://bugs.llvm.org/show_bug.cgi?id=37695 is not fixed. But since we have eliminated libclang for indexing and completion the bug no longer bothers us.

README.md

@@ -16,18 +16,18 @@ a C/C++/Objective-C language server.
 
 It makes use of C++17 features, has less third-party dependencies and slimmed-down code base. Cross reference features are strenghened, (see [wiki/FAQ](../../wiki/FAQ). It currently uses libclang to index C++ code but will switch to Clang C++ API. Refactoring and formatting are non-goals as they can be provided by clang-format, clang-include-fixer and other Clang based tools.
 
-The comparison with cquery as noted on 2018-07-09:
+The comparison with cquery as noted on 2018-07-15:
 
 |             | cquery                         | ccls                         |
 |------------ |--------------------------------|------------------------------|
 | third_party | more                           | fewer                        |
 | C++         | C++14                          | C++17                        |
-| clang API   | libclang (C)                   | libclang + clang/llvm C++    |
+| clang API   | libclang (C)                   | clang/llvm C++               |
 | Filesystem  | AbsolutePath + custom routines | llvm/Support                 |
 | index       | libclang                       | clangIndex, some enhancement |
 | pipeline    | index merge+id remapping       | simpler and more robust      |
 
-cquery has system include path detection (through running the compiler driver) while ccls does not.
+cquery has system include path detection (through running the compiler driver) while ccls uses clangDriver.
 
 # >>> [Getting started](../../wiki/Getting-started) (CLICK HERE) <<<
 

src/clang_complete.cc

@@ -9,6 +9,7 @@
 #include "clang/Frontend/FrontendDiagnostic.h"
 #include <clang/Sema/CodeCompleteConsumer.h>
 #include <llvm/ADT/Twine.h>
+#include <llvm/Config/llvm-config.h>
 #include <llvm/Support/Threading.h>
 using namespace clang;
 using namespace llvm;
@@ -444,8 +445,10 @@ void CompletionQueryMain(ClangCompleteManager* completion_manager) {
       CodeCompleteOptions Opts;
       LangOptions LangOpts;
       Opts.IncludeBriefComments = true;
-      Opts.LoadExternal = false;
+#if LLVM_VERSION_MAJOR >= 7
+      Opts.LoadExternal = true;
       Opts.IncludeFixIts = true;
+#endif
       CaptureCompletionResults capture(Opts);
       tu->Unit->CodeComplete(session->file.filename, request->position.line + 1,
                              request->position.character + 1, Remapped,

src/clang_tu.cc

@@ -89,7 +89,12 @@ ClangTranslationUnit::Create(const std::string &filepath,
         /*CaptureDiagnostics=*/true, Remapped,
         /*RemappedFilesKeepOriginalName=*/true, 1, TU_Prefix,
         /*CacheCodeCompletionResults=*/true, true,
-        /*AllowPCHWithCompilerErrors=*/true, SkipFunctionBodiesScope::None,
+        /*AllowPCHWithCompilerErrors=*/true,
+#if LLVM_VERSION_MAJOR >= 7
+        SkipFunctionBodiesScope::None,
+#else
+        false,
+#endif
         /*SingleFileParse=*/false,
         /*UserFilesAreVolatile=*/true, false,
         ret->PCHCO->getRawReader().getFormat(), &ErrUnit));

src/clang_utils.cc

@@ -6,6 +6,7 @@
 #include "utils.h"
 
 #include <clang/AST/Type.h>
+#include <llvm/Config/llvm-config.h>
 using namespace clang;
 using namespace llvm;
 
@@ -66,6 +67,7 @@ const char* ClangBuiltinTypeName(int kind) {
     return "double";
   case BuiltinType::LongDouble:
     return "long double";
+#if LLVM_VERSION_MAJOR >= 7
   case BuiltinType::ShortAccum:
     return "short _Accum";
   case BuiltinType::Accum:
@@ -114,6 +116,7 @@ const char* ClangBuiltinTypeName(int kind) {
     return "_Sat unsigned _Fract";
   case BuiltinType::BuiltinType::SatULongFract:
     return "_Sat unsigned long _Fract";
+#endif
   case BuiltinType::Float16:
     return "_Float16";
   case BuiltinType::Float128:
@@ -121,8 +124,10 @@ const char* ClangBuiltinTypeName(int kind) {
   case BuiltinType::WChar_S:
   case BuiltinType::WChar_U:
     return "wchar_t";
+#if LLVM_VERSION_MAJOR >= 7
   case BuiltinType::Char8:
     return "char8_t";
+#endif
   case BuiltinType::Char16:
     return "char16_t";
   case BuiltinType::Char32:

src/project.cc

@@ -14,12 +14,9 @@ using namespace ccls;
 
 #include <clang/Driver/Compilation.h>
 #include <clang/Driver/Driver.h>
-#include <clang/Driver/Options.h>
 #include <clang/Frontend/CompilerInstance.h>
 #include <clang/Tooling/CompilationDatabase.h>
 #include <llvm/ADT/ArrayRef.h>
-#include <llvm/Option/ArgList.h>
-#include <llvm/Option/OptTable.h>
 #include <llvm/Support/MemoryBuffer.h>
 #include <llvm/Support/LineIterator.h>
 using namespace clang;
@@ -99,22 +96,6 @@ Project::Entry GetCompilationEntryFromCompileCommandEntry(
   args.insert(args.end(), config->extra_flags.begin(),
               config->extra_flags.end());
 
-#if 1
-  std::unique_ptr<OptTable> Opts = driver::createDriverOptTable();
-  unsigned MissingArgIndex, MissingArgCount;
-  std::vector<const char*> cargs;
-  for (auto& arg : args)
-    cargs.push_back(arg.c_str());
-  InputArgList Args =
-      Opts->ParseArgs(makeArrayRef(cargs), MissingArgIndex, MissingArgCount,
-                      driver::options::CC1Option);
-  using namespace clang::driver::options;
-  for (const auto* A : Args.filtered(OPT_I, OPT_c_isystem, OPT_cxx_isystem,
-                                     OPT_isystem, OPT_idirafter))
-    config->angle_dirs.insert(entry.ResolveIfRelative(A->getValue()));
-  for (const auto* A : Args.filtered(OPT_I, OPT_iquote))
-    config->quote_dirs.insert(entry.ResolveIfRelative(A->getValue()));
-#else
   // a weird C++ deduction guide heap-use-after-free causes libclang to crash.
   IgnoringDiagConsumer DiagC;
   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts(new DiagnosticOptions());
@@ -164,7 +145,6 @@ Project::Entry GetCompilationEntryFromCompileCommandEntry(
         break;
     }
   }
-#endif
 
   for (size_t i = 1; i < args.size(); i++)
     // This is most likely the file path we will be passing to clang. The
@@ -176,9 +156,9 @@ Project::Entry GetCompilationEntryFromCompileCommandEntry(
       continue;
     }
 
-  // if (HeaderOpts.ResourceDir.empty() && HeaderOpts.UseBuiltinIncludes)
+  if (HeaderOpts.ResourceDir.empty() && HeaderOpts.UseBuiltinIncludes)
     args.push_back("-resource-dir=" + g_config->clang.resourceDir);
-  // if (CI->getFileSystemOpts().WorkingDir.empty())
+  if (CI->getFileSystemOpts().WorkingDir.empty())
     args.push_back("-working-directory=" + entry.directory);
 
   // There could be a clang version mismatch between what the project uses and