[Tooling][libclang] Remove unused CompilationDatabase::MappedSources

Summary:
This field is never assigned to and it's only ever read from libclang.
This patch removes it and adapts libclang to return constants.

Reviewers: klimek, bkramer

Reviewed By: klimek

Subscribers: cfe-commits, klimek

Differential Revision: https://reviews.llvm.org/D32351

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@303635 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Tooling/CompilationDatabase.h

@@ -60,16 +60,6 @@ struct CompileCommand {
 
   /// The output file associated with the command.
   std::string Output;
-
-  /// \brief An optional mapping from each file's path to its content for all
-  /// files needed for the compilation that are not available via the file
-  /// system.
-  ///
-  /// Note that a tool implementation is required to fall back to the file
-  /// system if a source file is not provided in the mapped sources, as
-  /// compilation databases will usually not provide all files in mapped sources
-  /// for performance reasons.
-  std::vector<std::pair<std::string, std::string> > MappedSources;
 };
 
 /// \brief Interface for compilation databases.

tools/libclang/CXCompilationDatabase.cpp

@@ -145,36 +145,23 @@ clang_CompileCommand_getArg(CXCompileCommand CCmd, unsigned Arg)
 unsigned
 clang_CompileCommand_getNumMappedSources(CXCompileCommand CCmd)
 {
-  if (!CCmd)
-    return 0;
-
-  return static_cast<CompileCommand *>(CCmd)->MappedSources.size();
+  // Left here for backward compatibility. No mapped sources exists in the C++
+  // backend anymore.
+  return 0;
 }
 
 CXString
 clang_CompileCommand_getMappedSourcePath(CXCompileCommand CCmd, unsigned I)
 {
-  if (!CCmd)
-    return cxstring::createNull();
-
-  CompileCommand *Cmd = static_cast<CompileCommand *>(CCmd);
-
-  if (I >= Cmd->MappedSources.size())
-    return cxstring::createNull();
-
-  return cxstring::createRef(Cmd->MappedSources[I].first.c_str());
+  // Left here for backward compatibility. No mapped sources exists in the C++
+  // backend anymore.
+  return cxstring::createNull();
 }
 
 CXString
 clang_CompileCommand_getMappedSourceContent(CXCompileCommand CCmd, unsigned I)
 {
-  if (!CCmd)
-    return cxstring::createNull();
-
-  CompileCommand *Cmd = static_cast<CompileCommand *>(CCmd);
-
-  if (I >= Cmd->MappedSources.size())
-    return cxstring::createNull();
-
-  return cxstring::createRef(Cmd->MappedSources[I].second.c_str());
+  // Left here for backward compatibility. No mapped sources exists in the C++
+  // backend anymore.
+  return cxstring::createNull();
 }