ccls/src/indexer.cc

#include "indexer.h"

#include "clang_utils.h"
#include "libclangmm/Cursor.h"
#include "libclangmm/Index.h"
#include "libclangmm/TranslationUnit.h"
#include "libclangmm/Utility.h"
#include "platform.h"
#include "serializer.h"
#include "timer.h"

#include <algorithm>
#include <chrono>

// TODO: See if we can use clang_indexLoc_getFileLocation to get a type ref on |Foobar| in DISALLOW_COPY(Foobar)

namespace {

const bool kIndexStdDeclarations = true;

void AddFuncRef(std::vector<IndexFuncRef>* result, IndexFuncRef ref) {
  if (!result->empty() && (*result)[result->size() - 1] == ref)
    return;
  result->push_back(ref);
}

Range Resolve(const CXSourceRange& range, CXFile* cx_file = nullptr) {
  CXSourceLocation start = clang_getRangeStart(range);
  CXSourceLocation end = clang_getRangeEnd(range);

  unsigned int start_line, start_column;
  clang_getSpellingLocation(start, cx_file, &start_line, &start_column, nullptr);
  unsigned int end_line, end_column;
  clang_getSpellingLocation(end, nullptr, &end_line, &end_column, nullptr);

  return Range(
    Position((int16_t)start_line, (int16_t)start_column) /*start*/,
    Position((int16_t)end_line, (int16_t)end_column) /*end*/);
}

Range ResolveSpelling(const CXCursor& cx_cursor, CXFile* cx_file = nullptr) {
  CXSourceRange cx_range = clang_Cursor_getSpellingNameRange(cx_cursor, 0, 0);
  return Resolve(cx_range, cx_file);
}

Range ResolveExtent(const CXCursor& cx_cursor, CXFile* cx_file = nullptr) {
  CXSourceRange cx_range = clang_getCursorExtent(cx_cursor);
  return Resolve(cx_range, cx_file);
}


struct NamespaceHelper {
  std::unordered_map<std::string, std::string> container_usr_to_qualified_name;

  void RegisterQualifiedName(std::string usr,
    const CXIdxContainerInfo* container,
    std::string qualified_name) {
    if (container) {
      std::string container_usr = clang::Cursor(container->cursor).get_usr();
      auto it = container_usr_to_qualified_name.find(container_usr);
      if (it != container_usr_to_qualified_name.end()) {
        container_usr_to_qualified_name[usr] =
          it->second + qualified_name + "::";
        return;
      }
    }

    container_usr_to_qualified_name[usr] = qualified_name + "::";
  }

  std::string QualifiedName(const CXIdxContainerInfo* container,
    std::string unqualified_name) {
    if (container) {
      std::string container_usr = clang::Cursor(container->cursor).get_usr();
      auto it = container_usr_to_qualified_name.find(container_usr);
      if (it != container_usr_to_qualified_name.end())
        return it->second + unqualified_name;

      // Anonymous namespaces are not processed by indexDeclaration. If we
      // encounter one insert it into map.
      if (container->cursor.kind == CXCursor_Namespace) {
        // assert(clang::Cursor(container->cursor).get_spelling() == "");
        container_usr_to_qualified_name[container_usr] = "::";
        return "::" + unqualified_name;
      }
    }
    return unqualified_name;
  }
};

struct IndexParam {
  // Only use this when strictly needed (ie, primary translation unit is
  // needed). Most logic should get the IndexFile instance via
  // |file_consumer|.
  //
  // This can be null if we're not generating an index for the primary
  // translation unit.
  IndexFile* primary_file = nullptr;

  clang::TranslationUnit* tu = nullptr;

  FileConsumer* file_consumer = nullptr;
  NamespaceHelper ns;

  IndexParam(clang::TranslationUnit* tu, FileConsumer* file_consumer) : tu(tu), file_consumer(file_consumer) {}
};

IndexFile* ConsumeFile(IndexParam* param, CXFile file) {
  bool is_first_ownership = false;
  IndexFile* db = param->file_consumer->TryConsumeFile(file, &is_first_ownership);

  // Mark dependency in primary file. If primary_file is null that means we're
  // doing a re-index in which case the dependency has already been established
  // in a previous index run.
  if (is_first_ownership && param->primary_file)
    param->primary_file->dependencies.push_back(db->path);

  if (is_first_ownership) {
    // Report skipped source range list.
    CXSourceRangeList* skipped = clang_getSkippedRanges(param->tu->cx_tu, file);
    for (unsigned i = 0; i < skipped->count; ++i) {
      Range range = Resolve(skipped->ranges[i]);
      // clang_getSkippedRanges reports start one token after the '#', move it
      // back so it starts at the '#'
      range.start.column -= 1;
      db->skipped_by_preprocessor.push_back(range);
    }
    clang_disposeSourceRangeList(skipped);
  }

  return db;
}

bool IsLocalSemanticContainer(CXCursorKind kind) {
  switch (kind) {
    case CXCursor_Namespace:
    case CXCursor_TranslationUnit:
    case CXCursor_StructDecl:
    case CXCursor_UnionDecl:
    case CXCursor_ClassDecl:
    case CXCursor_EnumDecl:
      return false;
    default:
      return true;
  }
}

// Returns true if the given entity kind can be called implicitly, ie, without
// actually being written in the source code.
bool CanBeCalledImplicitly(CXIdxEntityKind kind) {
  switch (kind) {
  case CXIdxEntity_CXXConstructor:
  case CXIdxEntity_CXXConversionFunction:
  case CXIdxEntity_CXXDestructor:
    return true;
  default:
    return false;
  }
}

// Returns true if the cursor spelling contains the given string. This is
// useful to check for implicit function calls.
bool CursorSpellingContainsString(CXCursor cursor, CXTranslationUnit cx_tu, std::string scanning_for) {
  CXSourceRange range = clang_Cursor_getSpellingNameRange(cursor, 0, 0);
  CXToken* tokens;
  unsigned num_tokens;
  clang_tokenize(cx_tu, range, &tokens, &num_tokens);

  bool result = false;

  for (unsigned i = 0; i < num_tokens; ++i) {
    CXString name = clang_getTokenSpelling(cx_tu, tokens[i]);
    if (strcmp(clang_getCString(name), scanning_for.c_str()) == 0) {
      result = true;
      break;
    }
    clang_disposeString(name);
  }

  clang_disposeTokens(cx_tu, tokens, num_tokens);
  return result;
}

// Returns the document content for the given range. May not work perfectly
// when there are tabs instead of spaces.
std::string GetDocumentContentInRange(CXTranslationUnit cx_tu, CXSourceRange range) {
  std::string result;

  CXToken* tokens;
  unsigned num_tokens;
  clang_tokenize(cx_tu, range, &tokens, &num_tokens);

  optional<Range> previous_token_range;

  for (unsigned i = 0; i < num_tokens; ++i) {
    // Add whitespace between the previous token and this one.
    Range token_range = Resolve(clang_getTokenExtent(cx_tu, tokens[i]));
    if (previous_token_range) {
      // Insert newlines.
      int16_t line_delta = token_range.start.line - previous_token_range->end.line;
      assert(line_delta >= 0);
      if (line_delta > 0) {
        result.append((size_t)line_delta, '\n');
        // Reset column so we insert starting padding.
        previous_token_range->end.column = 0;
      }
      // Insert spaces.
      int16_t column_delta = token_range.start.column - previous_token_range->end.column;
      assert(column_delta >= 0);
      result.append((size_t)column_delta, ' ');
    }
    previous_token_range = token_range;

    // Add token content.
    CXString spelling = clang_getTokenSpelling(cx_tu, tokens[i]);
    result += clang_getCString(spelling);
    clang_disposeString(spelling);
  }

  clang_disposeTokens(cx_tu, tokens, num_tokens);

  return result;
}

}  // namespace



































IndexFile::IndexFile(const std::string& path) : id_cache(path), path(path) {
  // TODO: Reconsider if we should still be reusing the same id_cache.
  // Preallocate any existing resolved ids.
  for (const auto& entry : id_cache.usr_to_type_id)
    types.push_back(IndexType(entry.second, entry.first));
  for (const auto& entry : id_cache.usr_to_func_id)
    funcs.push_back(IndexFunc(entry.second, entry.first));
  for (const auto& entry : id_cache.usr_to_var_id)
    vars.push_back(IndexVar(entry.second, entry.first));
}

// TODO: Optimize for const char*?
IndexTypeId IndexFile::ToTypeId(const std::string& usr) {
  auto it = id_cache.usr_to_type_id.find(usr);
  if (it != id_cache.usr_to_type_id.end())
    return it->second;

  IndexTypeId id(types.size());
  types.push_back(IndexType(id, usr));
  id_cache.usr_to_type_id[usr] = id;
  id_cache.type_id_to_usr[id] = usr;
  return id;
}
IndexFuncId IndexFile::ToFuncId(const std::string& usr) {
  auto it = id_cache.usr_to_func_id.find(usr);
  if (it != id_cache.usr_to_func_id.end())
    return it->second;

  IndexFuncId id(funcs.size());
  funcs.push_back(IndexFunc(id, usr));
  id_cache.usr_to_func_id[usr] = id;
  id_cache.func_id_to_usr[id] = usr;
  return id;
}
IndexVarId IndexFile::ToVarId(const std::string& usr) {
  auto it = id_cache.usr_to_var_id.find(usr);
  if (it != id_cache.usr_to_var_id.end())
    return it->second;

  IndexVarId id(vars.size());
  vars.push_back(IndexVar(id, usr));
  id_cache.usr_to_var_id[usr] = id;
  id_cache.var_id_to_usr[id] = usr;
  return id;
}

IndexTypeId IndexFile::ToTypeId(const CXCursor& cursor) {
  return ToTypeId(clang::Cursor(cursor).get_usr());
}

IndexFuncId IndexFile::ToFuncId(const CXCursor& cursor) {
  return ToFuncId(clang::Cursor(cursor).get_usr());
}

IndexVarId IndexFile::ToVarId(const CXCursor& cursor) {
  return ToVarId(clang::Cursor(cursor).get_usr());
}

IndexType* IndexFile::Resolve(IndexTypeId id) {
  return &types[id.id];
}
IndexFunc* IndexFile::Resolve(IndexFuncId id) {
  return &funcs[id.id];
}
IndexVar* IndexFile::Resolve(IndexVarId id) {
  return &vars[id.id];
}

std::string IndexFile::ToString() {
  return Serialize(*this);
}

IndexType::IndexType(IndexTypeId id, const std::string& usr)
    : def(usr), id(id) {
  assert(usr.size() > 0);
  // std::cerr << "Creating type with usr " << usr << std::endl;
}

void RemoveItem(std::vector<Range>& ranges, Range to_remove) {
  auto it = std::find(ranges.begin(), ranges.end(), to_remove);
  if (it != ranges.end())
    ranges.erase(it);
}

template <typename T>
void UniqueAdd(std::vector<T>& values, T value) {
  if (std::find(values.begin(), values.end(), value) == values.end())
    values.push_back(value);
}

IdCache::IdCache(const std::string& primary_file)
  : primary_file(primary_file) {}

template <typename T>
bool Contains(const std::vector<T>& vec, const T& element) {
  for (const T& entry : vec) {
    if (entry == element)
      return true;
  }
  return false;
}

int abortQuery(CXClientData client_data, void* reserved) {
  // 0 -> continue
  return 0;
}
void diagnostic(CXClientData client_data,
                CXDiagnosticSet diagnostics,
                void* reserved) {
}

CXIdxClientFile enteredMainFile(CXClientData client_data,
                                CXFile mainFile,
                                void* reserved) {
  return nullptr;
}

CXIdxClientFile ppIncludedFile(CXClientData client_data,
                               const CXIdxIncludedFileInfo* file) {
  IndexParam* param = static_cast<IndexParam*>(client_data);

  // file->hashLoc only has the position of the hash. We don't have the full
  // range for the include.
  CXSourceLocation hash_loc = clang_indexLoc_getCXSourceLocation(file->hashLoc);
  CXFile cx_file;
  unsigned int line;
  clang_getSpellingLocation(hash_loc, &cx_file, &line, nullptr, nullptr);

  IndexFile* db = ConsumeFile(param, cx_file);
  if (!db)
    return nullptr;

  IndexInclude include;
  include.line = line;
  include.resolved_path = FileName(file->file);
  db->includes.push_back(include);

  return nullptr;
}

CXIdxClientASTFile importedASTFile(CXClientData client_data,
                                   const CXIdxImportedASTFileInfo*) {
  return nullptr;
}

CXIdxClientContainer startedTranslationUnit(CXClientData client_data,
                                            void* reserved) {
  return nullptr;
}

clang::VisiterResult DumpVisitor(clang::Cursor cursor,
                                 clang::Cursor parent,
                                 int* level) {
  for (int i = 0; i < *level; ++i)
    std::cerr << "  ";
  std::cerr << clang::ToString(cursor.get_kind()) << " "
            << cursor.get_spelling() << std::endl;

  *level += 1;
  cursor.VisitChildren(&DumpVisitor, level);
  *level -= 1;

  return clang::VisiterResult::Continue;
}

void Dump(clang::Cursor cursor) {
  int level = 0;
  cursor.VisitChildren(&DumpVisitor, &level);
}

struct FindChildOfKindParam {
  CXCursorKind target_kind;
  optional<clang::Cursor> result;

  FindChildOfKindParam(CXCursorKind target_kind) : target_kind(target_kind) {}
};

clang::VisiterResult FindChildOfKindVisitor(clang::Cursor cursor,
                                            clang::Cursor parent,
                                            FindChildOfKindParam* param) {
  if (cursor.get_kind() == param->target_kind) {
    param->result = cursor;
    return clang::VisiterResult::Break;
  }

  return clang::VisiterResult::Recurse;
}

optional<clang::Cursor> FindChildOfKind(clang::Cursor cursor,
                                        CXCursorKind kind) {
  FindChildOfKindParam param(kind);
  cursor.VisitChildren(&FindChildOfKindVisitor, &param);
  return param.result;
}

clang::VisiterResult FindTypeVisitor(clang::Cursor cursor,
                                     clang::Cursor parent,
                                     optional<clang::Cursor>* result) {
  switch (cursor.get_kind()) {
    case CXCursor_TypeRef:
    case CXCursor_TemplateRef:
      *result = cursor;
      return clang::VisiterResult::Break;
    default:
      break;
  }

  return clang::VisiterResult::Recurse;
}

optional<clang::Cursor> FindType(clang::Cursor cursor) {
  optional<clang::Cursor> result;
  cursor.VisitChildren(&FindTypeVisitor, &result);
  return result;
}

bool IsTypeDefinition(const CXIdxContainerInfo* container) {
  if (!container)
    return false;

  switch (container->cursor.kind) {
    case CXCursor_EnumDecl:
    case CXCursor_UnionDecl:
    case CXCursor_StructDecl:
    case CXCursor_ClassDecl:
      return true;
    default:
      return false;
  }
}

struct VisitDeclForTypeUsageParam {
  IndexFile* db;
  int has_processed_any = false;
  optional<clang::Cursor> previous_cursor;
  optional<IndexTypeId> initial_type;

  VisitDeclForTypeUsageParam(IndexFile* db) : db(db) {}
};

void VisitDeclForTypeUsageVisitorHandler(clang::Cursor cursor,
                                         VisitDeclForTypeUsageParam* param) {
  param->has_processed_any = true;
  IndexFile* db = param->db;

  std::string referenced_usr =
      cursor.get_referenced()
          .template_specialization_to_template_definition()
          .get_usr();
  // TODO: things in STL cause this to be empty. Figure out why and document it.
  if (referenced_usr == "")
    return;

  IndexTypeId ref_type_id = db->ToTypeId(referenced_usr);

  if (!param->initial_type)
    param->initial_type = ref_type_id;

  IndexType* ref_type_def = db->Resolve(ref_type_id);
  // TODO: Should we even be visiting this if the file is not from the main
  // def? Try adding assert on |loc| later.
  Range loc = ResolveSpelling(cursor.cx_cursor);
  UniqueAdd(ref_type_def->uses, loc);
}

clang::VisiterResult VisitDeclForTypeUsageVisitor(
    clang::Cursor cursor,
    clang::Cursor parent,
    VisitDeclForTypeUsageParam* param) {
  switch (cursor.get_kind()) {
    case CXCursor_TemplateRef:
    case CXCursor_TypeRef:
      if (param->previous_cursor) {
        VisitDeclForTypeUsageVisitorHandler(param->previous_cursor.value(),
                                            param);
      }

      param->previous_cursor = cursor;
      return clang::VisiterResult::Continue;

    // We do not want to recurse for everything, since if we do that we will end
    // up visiting method definition bodies/etc. Instead, we only recurse for
    // things that can logically appear as part of an inline variable
    // initializer,
    // ie,
    //
    //  class Foo {
    //   int x = (Foo)3;
    //  }
    case CXCursor_CallExpr:
    case CXCursor_CStyleCastExpr:
    case CXCursor_CXXStaticCastExpr:
    case CXCursor_CXXReinterpretCastExpr:
      return clang::VisiterResult::Recurse;

    default:
      return clang::VisiterResult::Continue;
  }

  return clang::VisiterResult::Continue;
}

// Finds the cursor associated with the declaration type of |cursor|. This
// strips
// qualifies from |cursor| (ie, Foo* => Foo) and removes template arguments
// (ie, Foo<A,B> => Foo<*,*>).
optional<IndexTypeId> ResolveToDeclarationType(IndexFile* db,
                                               clang::Cursor cursor) {
  clang::Cursor declaration = cursor.get_declaration();
  declaration = declaration.template_specialization_to_template_definition();
  std::string usr = declaration.get_usr();
  if (usr != "")
    return db->ToTypeId(usr);
  return nullopt;
}

// Add usages to any seen TypeRef or TemplateRef under the given |decl_cursor|.
// This returns the first seen TypeRef or TemplateRef value, which can be
// useful if trying to figure out ie, what a using statement refers to. If
// trying to generally resolve a cursor to a type, use
// ResolveToDeclarationType, which works in more scenarios.
optional<IndexTypeId> AddDeclTypeUsages(
    IndexFile* db,
    clang::Cursor decl_cursor,
    const CXIdxContainerInfo* semantic_container,
    const CXIdxContainerInfo* lexical_container) {

  // std::cerr << std::endl << "AddDeclUsages " << decl_cursor.get_spelling() <<
  // std::endl;
  // Dump(decl_cursor);

  //
  // The general AST format for definitions follows this pattern:
  //
  //  template<typename A, typename B>
  //  struct Container;
  //
  //  struct S1;
  //  struct S2;
  //
  //  Container<Container<S1, S2>, S2> foo;
  //
  //  =>
  //
  //  VarDecl
  //    TemplateRef Container
  //    TemplateRef Container
  //    TypeRef struct S1
  //    TypeRef struct S2
  //    TypeRef struct S2
  //
  //
  // Here is another example:
  //
  //  enum A {};
  //  enum B {};
  //
  //  template<typename T>
  //  struct Foo {
  //    struct Inner {};
  //  };
  //
  //  Foo<A>::Inner a;
  //  Foo<B> b;
  //
  //  =>
  //
  //  EnumDecl A
  //  EnumDecl B
  //  ClassTemplate Foo
  //    TemplateTypeParameter T
  //    StructDecl Inner
  //  VarDecl a
  //    TemplateRef Foo
  //    TypeRef enum A
  //    TypeRef struct Foo<enum A>::Inner
  //    CallExpr Inner
  //  VarDecl b
  //    TemplateRef Foo
  //    TypeRef enum B
  //    CallExpr Foo
  //
  //
  // Determining the actual type of the variable/declaration from just the
  // children is tricky. Doing so would require looking up the template
  // definition associated with a TemplateRef, figuring out how many children
  // it has, and then skipping that many TypeRef values. This also has to work
  // with the example below (skipping the last TypeRef). As a result, we
  // determine variable types using |ResolveToDeclarationType|.
  //
  //
  // We skip the last type reference for methods/variables which are defined
  // out-of-line w.r.t. the parent type.
  //
  //  S1* Foo::foo() {}
  //
  // The above example looks like this in the AST:
  //
  //  CXXMethod foo
  //    TypeRef struct S1
  //    TypeRef class Foo
  //    CompoundStmt
  //      ...
  //
  //  The second TypeRef is an uninteresting usage.
  bool process_last_type_ref = true;
  if (IsTypeDefinition(semantic_container) &&
      !IsTypeDefinition(lexical_container)) {
    //
    // In some code, such as the following example, we receive a cursor which is
    // not
    // a definition and is not associated with a definition due to an error
    // condition.
    // In this case, it is the Foo::Foo constructor.
    //
    //  struct Foo {};
    //
    //  template<class T>
    //  Foo::Foo() {}
    //
    if (!decl_cursor.is_definition()) {
      // TODO: I don't think this resolution ever works.
      clang::Cursor def = decl_cursor.get_definition();
      if (def.get_kind() != CXCursor_FirstInvalid) {
        std::cerr << "Successful resolution of decl usage to definition"
                  << std::endl;
        decl_cursor = def;
      }
    }
    process_last_type_ref = false;
  }

  VisitDeclForTypeUsageParam param(db);
  decl_cursor.VisitChildren(&VisitDeclForTypeUsageVisitor, &param);

  // VisitDeclForTypeUsageVisitor guarantees that if there are multiple TypeRef
  // children, the first one will always be visited.
  if (param.previous_cursor && process_last_type_ref) {
    VisitDeclForTypeUsageVisitorHandler(param.previous_cursor.value(), &param);
  } else {
    // If we are not processing the last type ref, it *must* be a TypeRef or
    // TemplateRef.
    //
    // We will not visit every child if the is_interseting is false, so
    // previous_cursor
    // may not point to the last TemplateRef.
    assert(param.previous_cursor.has_value() == false ||
           (param.previous_cursor.value().get_kind() == CXCursor_TypeRef ||
            param.previous_cursor.value().get_kind() == CXCursor_TemplateRef));
  }

  return param.initial_type;
}

// Various versions of LLVM (ie, 4.0) will not visit inline variable references
// for template arguments.
clang::VisiterResult AddDeclInitializerUsagesVisitor(clang::Cursor cursor,
                                                     clang::Cursor parent,
                                                     IndexFile* db) {
  /*
    We need to index the |DeclRefExpr| below (ie, |var| inside of
    Foo<int>::var).

      template<typename T>
      struct Foo {
        static constexpr int var = 3;
      };

      int a = Foo<int>::var;

      =>

      VarDecl a
        UnexposedExpr var
          DeclRefExpr var
            TemplateRef Foo

  */

  switch (cursor.get_kind()) {
    case CXCursor_DeclRefExpr: {
      if (cursor.get_referenced().get_kind() != CXCursor_VarDecl)
        break;

      // TODO: when we resolve the template type to the definition, we get a
      // different USR.

      // clang::Cursor ref =
      // cursor.get_referenced().template_specialization_to_template_definition().get_type().strip_qualifiers().get_usr();
      // std::string ref_usr =
      // cursor.get_referenced().template_specialization_to_template_definition().get_type().strip_qualifiers().get_usr();
      std::string ref_usr =
          cursor.get_referenced()
              .template_specialization_to_template_definition()
              .get_usr();
      // std::string ref_usr = ref.get_usr();
      if (ref_usr == "")
        break;

      Range loc = ResolveSpelling(cursor.cx_cursor);
      // std::cerr << "Adding usage to id=" << ref_id.id << " usr=" << ref_usr
      // << " at " << loc.ToString() << std::endl;
      IndexVarId ref_id = db->ToVarId(ref_usr);
      IndexVar* ref_def = db->Resolve(ref_id);
      UniqueAdd(ref_def->uses, loc);
      break;
    }

    default:
      break;
  }

  return clang::VisiterResult::Recurse;
}

void AddDeclInitializerUsages(IndexFile* db, clang::Cursor decl_cursor) {
  decl_cursor.VisitChildren(&AddDeclInitializerUsagesVisitor, db);
}

bool AreEqualLocations(CXIdxLoc loc, CXCursor cursor) {
  // clang_getCursorExtent
  // clang_Cursor_getSpellingNameRange

  return clang_equalLocations(
    clang_indexLoc_getCXSourceLocation(loc),
    //clang_getRangeStart(clang_getCursorExtent(cursor)));
    clang_getRangeStart(clang_Cursor_getSpellingNameRange(cursor, 0, 0)));
}




clang::VisiterResult VisitMacroDefinitionAndExpansions(clang::Cursor cursor, clang::Cursor parent, IndexParam* param) {
  switch (cursor.get_kind()) {
    case CXCursor_MacroDefinition:
    case CXCursor_MacroExpansion: {
      // Resolve location, find IndexFile instance.
      CXSourceRange cx_source_range = clang_Cursor_getSpellingNameRange(cursor.cx_cursor, 0, 0);
      CXSourceLocation start = clang_getRangeStart(cx_source_range);
      if (clang_Location_isInSystemHeader(start))
        break;
      CXFile file;
      Range decl_loc_spelling = Resolve(cx_source_range, &file);
      IndexFile* db = ConsumeFile(param, file);
      if (!db)
        break;

      // TODO: Considering checking clang_Cursor_isMacroFunctionLike, but the
      // only real difference will be that we show 'callers' instead of 'refs'
      // (especially since macros cannot have overrides)

      std::string decl_usr;
      if (cursor.get_kind() == CXCursor_MacroDefinition)
        decl_usr = cursor.get_usr();
      else
        decl_usr = cursor.get_referenced().get_usr();

      IndexVarId var_id = db->ToVarId(decl_usr);
      IndexVar* var_def = db->Resolve(var_id);
      UniqueAdd(var_def->uses, decl_loc_spelling);

      if (cursor.get_kind() == CXCursor_MacroDefinition) {
        var_def->def.short_name = cursor.get_display_name();
        var_def->def.detailed_name = var_def->def.short_name;
        var_def->def.is_local = false;
        var_def->def.definition_spelling = decl_loc_spelling;
        var_def->def.definition_extent = ResolveExtent(cursor.cx_cursor);;
      }

      break;
    }
    default:
      break;
  }

  return clang::VisiterResult::Continue;
}




















































void indexDeclaration(CXClientData client_data, const CXIdxDeclInfo* decl) {
  if (!kIndexStdDeclarations && clang_Location_isInSystemHeader(clang_indexLoc_getCXSourceLocation(decl->loc)))
    return;

  assert(AreEqualLocations(decl->loc, decl->cursor));

  CXFile file;
  clang_getSpellingLocation(clang_indexLoc_getCXSourceLocation(decl->loc), &file, nullptr, nullptr, nullptr);
  IndexParam* param = static_cast<IndexParam*>(client_data);
  IndexFile* db = ConsumeFile(param, file);
  if (!db)
    return;

  NamespaceHelper* ns = &param->ns;


  //std::cerr << "DECL kind=" << decl->entityInfo->kind << " at " << db->id_cache.Resolve(decl->cursor, false).ToPrettyString(&db->id_cache) << std::endl;

  switch (decl->entityInfo->kind) {
    case CXIdxEntity_CXXNamespace: {
      ns->RegisterQualifiedName(decl->entityInfo->USR, decl->semanticContainer,
                                decl->entityInfo->name);
      break;
    }

    case CXIdxEntity_EnumConstant:
    case CXIdxEntity_Field:
    case CXIdxEntity_Variable:
    case CXIdxEntity_CXXStaticVariable: {
      Range decl_loc_spelling = ResolveSpelling(decl->cursor);

      clang::Cursor decl_cursor = decl->cursor;

      // Do not index implicit template instantiations.
      if (decl_cursor !=
          decl_cursor.template_specialization_to_template_definition())
        break;

      std::string decl_usr = decl_cursor.get_usr();

      IndexVarId var_id = db->ToVarId(decl->entityInfo->USR);
      IndexVar* var = db->Resolve(var_id);

      // TODO: Eventually run with this if. Right now I want to iron out bugs
      // this may shadow.
      // TODO: Verify this gets called multiple times
      // if (!decl->isRedeclaration) {
      var->def.short_name = decl->entityInfo->name;

      std::string type_name = clang::ToString(clang_getTypeSpelling(clang_getCursorType(decl->cursor)));
      var->def.detailed_name = type_name + " " + ns->QualifiedName(decl->semanticContainer, var->def.short_name);

      var->def.is_local = !decl->semanticContainer || IsLocalSemanticContainer(decl->semanticContainer->cursor.kind);

      //}

      if (decl->isDefinition) {
        var->def.definition_spelling = ResolveSpelling(decl->cursor);
        var->def.definition_extent = ResolveExtent(decl->cursor);;
      }
      else {
        var->def.declaration = ResolveSpelling(decl->cursor);
      }
      UniqueAdd(var->uses, decl_loc_spelling);

      // std::cerr << std::endl << "Visiting declaration" << std::endl;
      // Dump(decl_cursor);

      AddDeclInitializerUsages(db, decl_cursor);
      var = db->Resolve(var_id);

      // Declaring variable type information. Note that we do not insert an
      // interesting reference for parameter declarations - that is handled when
      // the function declaration is encountered since we won't receive ParmDecl
      // declarations for unnamed parameters.
      // TODO: See if we can remove this function call.
      AddDeclTypeUsages(
          db, decl_cursor,
          decl->semanticContainer, decl->lexicalContainer);

      // We don't need to assign declaring type multiple times if this variable
      // has already been seen.
      if (!decl->isRedeclaration) {
        optional<IndexTypeId> var_type = ResolveToDeclarationType(db, decl_cursor);
        if (var_type.has_value()) {
          // Don't treat enum definition variables as instantiations.
          bool is_enum_member = decl->semanticContainer && decl->semanticContainer->cursor.kind == CXCursor_EnumDecl;
          if (!is_enum_member)
            db->Resolve(var_type.value())->instances.push_back(var_id);

          var->def.variable_type = var_type.value();
        }
      }

      // TODO: Refactor handlers so more things are under 'if (!decl->isRedeclaration)'
      if (decl->isDefinition && IsTypeDefinition(decl->semanticContainer)) {
        IndexTypeId declaring_type_id =
          db->ToTypeId(decl->semanticContainer->cursor);
        IndexType* declaring_type_def = db->Resolve(declaring_type_id);
        var->def.declaring_type = declaring_type_id;
        declaring_type_def->def.vars.push_back(var_id);
      }

      break;
    }

    case CXIdxEntity_Function:
    case CXIdxEntity_CXXConstructor:
    case CXIdxEntity_CXXDestructor:
    case CXIdxEntity_CXXInstanceMethod:
    case CXIdxEntity_CXXStaticMethod:
    case CXIdxEntity_CXXConversionFunction: {
      Range decl_spelling = ResolveSpelling(decl->cursor);
      Range decl_extent = ResolveExtent(decl->cursor);

      clang::Cursor decl_cursor = decl->cursor;
      clang::Cursor decl_cursor_resolved = decl_cursor.template_specialization_to_template_definition();
      bool is_template_specialization = decl_cursor != decl_cursor_resolved;

      IndexFuncId func_id = db->ToFuncId(decl_cursor_resolved.cx_cursor);
      IndexFunc* func = db->Resolve(func_id);

      // We don't actually need to know the return type, but we need to mark it
      // as an interesting usage.
      AddDeclTypeUsages(db, decl_cursor,
                        decl->semanticContainer, decl->lexicalContainer);

      // Add definition or declaration. This is a bit tricky because we treat
      // template specializations as declarations, even though they are
      // technically definitions.
      // TODO: Support multiple function definitions, which is common for
      //       template specializations.
      if (decl->isDefinition && !is_template_specialization) {
        //assert(!func->def.definition_spelling);
        //assert(!func->def.definition_extent);
        func->def.definition_spelling = decl_spelling;
        func->def.definition_extent = decl_extent;
      }
      else {
        IndexFunc::Declaration declaration;
        declaration.spelling = decl_spelling;
        declaration.extent = decl_extent;
        declaration.content = GetDocumentContentInRange(param->tu->cx_tu, clang_getCursorExtent(decl->cursor));

        // Add parameters.
        for (clang::Cursor arg : decl_cursor.get_arguments()) {
          switch (arg.get_kind()) {
            case CXCursor_ParmDecl: {
              Range param_spelling = ResolveSpelling(arg.cx_cursor);

              // If the name is empty (which is common for parameters), clang
              // will report a range with length 1, which is not correct.
              if (param_spelling.start.column == (param_spelling.end.column - 1) &&
                  arg.get_display_name().empty()) {
                param_spelling.end.column -= 1;
              }

              declaration.param_spellings.push_back(param_spelling);
              break;
            }
            default:
              break;
          }
        }

        func->declarations.push_back(declaration);
      }

      // Emit definition data for the function. We do this even if it isn't a
      // definition because there can be, for example, interfaces, or a class
      // declaration that doesn't have a definition yet. If we never end up
      // indexing the definition, then there will not be any (ie) outline
      // information.
      if (!is_template_specialization) {
        func->def.short_name = decl->entityInfo->name;

        // Build detailed name. The type desc looks like void (void *). We
        // insert the qualified name before the first '('.
        std::string qualified_name = ns->QualifiedName(decl->semanticContainer, func->def.short_name);
        std::string type_desc = decl_cursor.get_type_description();
        size_t offset = type_desc.find('(');
        type_desc.insert(offset, qualified_name);
        func->def.detailed_name = type_desc;

        // Add function usage information. We only want to do it once per
        // definition/declaration. Do it on definition since there should only
        // ever be one of those in the entire program.
        if (IsTypeDefinition(decl->semanticContainer)) {
          IndexTypeId declaring_type_id =
              db->ToTypeId(decl->semanticContainer->cursor);
          IndexType* declaring_type_def = db->Resolve(declaring_type_id);
          func->def.declaring_type = declaring_type_id;

          // Mark a type reference at the ctor/dtor location.
          if (decl->entityInfo->kind == CXIdxEntity_CXXConstructor)
            UniqueAdd(declaring_type_def->uses, decl_spelling);
          if (decl->entityInfo->kind == CXIdxEntity_CXXDestructor) {
            Range dtor_type_range = decl_spelling;
            dtor_type_range.start.column += 1; // Don't count the leading ~
            UniqueAdd(declaring_type_def->uses, dtor_type_range);
          }

          // Add function to declaring type.
          UniqueAdd(declaring_type_def->def.funcs, func_id);
        }

        // Process inheritance.
        if (clang_CXXMethod_isVirtual(decl->cursor)) {
          CXCursor* overridden;
          unsigned int num_overridden;
          clang_getOverriddenCursors(decl->cursor, &overridden,
            &num_overridden);

          // FIXME if it ever shows up. Methods should only ever have 1 base
          // type, though.
          if (num_overridden > 1)
            std::cerr << "[indexer]: warning: multiple base overrides for " << func->def.detailed_name << std::endl;

          for (unsigned i = 0; i < num_overridden; ++i) {
            clang::Cursor parent = overridden[i];
            IndexFuncId parent_id = db->ToFuncId(parent.get_usr());
            IndexFunc* parent_def = db->Resolve(parent_id);
            func = db->Resolve(func_id);  // ToFuncId invalidated func_def

            func->def.base = parent_id;
            parent_def->derived.push_back(func_id);
          }

          clang_disposeOverriddenCursors(overridden);
        }
      }
      break;
    }

    case CXIdxEntity_Typedef:
    case CXIdxEntity_CXXTypeAlias: {
      Range decl_loc_spelling = ResolveSpelling(decl->cursor);

      // Note we want to fetch the first TypeRef. Running
      // ResolveCursorType(decl->cursor) would return
      // the type of the typedef/using, not the type of the referenced type.
      optional<IndexTypeId> alias_of =
          AddDeclTypeUsages(db, decl->cursor,
                            decl->semanticContainer, decl->lexicalContainer);

      IndexTypeId type_id = db->ToTypeId(decl->entityInfo->USR);
      IndexType* type = db->Resolve(type_id);

      if (alias_of)
        type->def.alias_of = alias_of.value();

      type->def.short_name = decl->entityInfo->name;
      type->def.detailed_name =
          ns->QualifiedName(decl->semanticContainer, type->def.short_name);

      type->def.definition_spelling = ResolveSpelling(decl->cursor);
      type->def.definition_extent = ResolveExtent(decl->cursor);
      UniqueAdd(type->uses, decl_loc_spelling);
      break;
    }

    case CXIdxEntity_Enum:
    case CXIdxEntity_Union:
    case CXIdxEntity_Struct:
    case CXIdxEntity_CXXClass: {
      Range decl_loc_spelling = ResolveSpelling(decl->cursor);

      IndexTypeId type_id = db->ToTypeId(decl->entityInfo->USR);
      IndexType* type = db->Resolve(type_id);

      // TODO: Eventually run with this if. Right now I want to iron out bugs
      // this may shadow.
      // TODO: For type section, verify if this ever runs for non definitions?
      // if (!decl->isRedeclaration) {

      // name can be null in an anonymous struct (see
      // tests/types/anonymous_struct.cc).
      if (decl->entityInfo->name) {
        ns->RegisterQualifiedName(decl->entityInfo->USR,
                                  decl->semanticContainer,
                                  decl->entityInfo->name);
        type->def.short_name = decl->entityInfo->name;
      } else {
        type->def.short_name = "<anonymous>";
      }

      type->def.detailed_name =
          ns->QualifiedName(decl->semanticContainer, type->def.short_name);

      // }

      assert(decl->isDefinition);
      type->def.definition_spelling = ResolveSpelling(decl->cursor);
      type->def.definition_extent = ResolveExtent(decl->cursor);
      UniqueAdd(type->uses, decl_loc_spelling);

      // type_def->alias_of
      // type_def->funcs
      // type_def->types
      // type_def->uses
      // type_def->vars

      // Add type-level inheritance information.
      CXIdxCXXClassDeclInfo const* class_info =
          clang_index_getCXXClassDeclInfo(decl);
      if (class_info) {
        for (unsigned int i = 0; i < class_info->numBases; ++i) {
          const CXIdxBaseClassInfo* base_class = class_info->bases[i];

          AddDeclTypeUsages(db, base_class->cursor,
                            decl->semanticContainer, decl->lexicalContainer);
          optional<IndexTypeId> parent_type_id =
              ResolveToDeclarationType(db, base_class->cursor);
          // type_def ptr could be invalidated by ResolveToDeclarationType.
          type = db->Resolve(type_id);
          if (parent_type_id) {
            IndexType* parent_type_def =
                db->Resolve(parent_type_id.value());
            parent_type_def->derived.push_back(type_id);
            type->def.parents.push_back(parent_type_id.value());
          }
        }
      }
      break;
    }

    default:
      std::cerr
          << "!! Unhandled indexDeclaration:     "
          << clang::Cursor(decl->cursor).ToString() << " at "
          << ResolveSpelling(decl->cursor).start.ToString()
          << std::endl;
      std::cerr << "     entityInfo->kind  = " << decl->entityInfo->kind
                << std::endl;
      std::cerr << "     entityInfo->USR   = " << decl->entityInfo->USR
                << std::endl;
      if (decl->declAsContainer)
        std::cerr << "     declAsContainer   = "
                  << clang::Cursor(decl->declAsContainer->cursor).ToString()
                  << std::endl;
      if (decl->semanticContainer)
        std::cerr << "     semanticContainer = "
                  << clang::Cursor(decl->semanticContainer->cursor).ToString()
                  << std::endl;
      if (decl->lexicalContainer)
        std::cerr << "     lexicalContainer  = "
                  << clang::Cursor(decl->lexicalContainer->cursor).get_usr()
                  << std::endl;
      break;
  }
}

bool IsFunctionCallContext(CXCursorKind kind) {
  switch (kind) {
    case CXCursor_FunctionDecl:
    case CXCursor_CXXMethod:
    case CXCursor_Constructor:
    case CXCursor_Destructor:
    case CXCursor_ConversionFunction:
    case CXCursor_FunctionTemplate:
    case CXCursor_OverloadedDeclRef:
    // TODO: we need to test lambdas
    case CXCursor_LambdaExpr:
      return true;

    default:
      break;
  }

  return false;
}
















































void indexEntityReference(CXClientData client_data,
                          const CXIdxEntityRefInfo* ref) {
  // Don't index references from or to system headers.
  if (clang_Location_isInSystemHeader(clang_indexLoc_getCXSourceLocation(ref->loc)) ||
      clang_Location_isInSystemHeader(clang_getCursorLocation(ref->referencedEntity->cursor)))
    return;

  //assert(AreEqualLocations(ref->loc, ref->cursor));

//  if (clang_Location_isInSystemHeader(clang_getCursorLocation(ref->cursor)) ||
//      clang_Location_isInSystemHeader(
//          clang_getCursorLocation(ref->referencedEntity->cursor)))
//    return;

  // TODO: Use clang_getFileUniqueID
  CXFile file;
  clang_getSpellingLocation(clang_indexLoc_getCXSourceLocation(ref->loc), &file, nullptr, nullptr, nullptr);
  IndexParam* param = static_cast<IndexParam*>(client_data);
  IndexFile* db = ConsumeFile(param, file);
  if (!db)
    return;

  // ref->cursor mainFile=0
  // ref->loc mainFile=1
  // ref->referencedEntity mainFile=1
  //
  // Regardless, we need to do more advanced location processing to handle multiple output IndexFile instances.
  //bool mainFile = clang_Location_isFromMainFile(clang_indexLoc_getCXSourceLocation(ref->loc));
  //Range loc_spelling = param->db->id_cache.ForceResolveSpelling(ref->cursor, false /*interesting*/);
  //std::cerr << "mainFile: " << mainFile << ", loc: " << loc_spelling.ToString() << std::endl;

  // Don't index references that are not from the main file.
  //if (!clang_Location_isFromMainFile(clang_getCursorLocation(ref->cursor)))
  //  return;



  clang::Cursor cursor(ref->cursor);

  // std::cerr << "REF kind=" << ref->referencedEntity->kind << " at " <<
  // db->id_cache.Resolve(cursor, false).ToPrettyString(&db->id_cache) <<
  // std::endl;

  switch (ref->referencedEntity->kind) {
    case CXIdxEntity_CXXNamespaceAlias:
    case CXIdxEntity_CXXNamespace: {
      // We don't index namespace usages.
      break;
    }

    case CXIdxEntity_EnumConstant:
    case CXIdxEntity_CXXStaticVariable:
    case CXIdxEntity_Variable:
    case CXIdxEntity_Field: {
      Range loc_spelling = ResolveSpelling(ref->cursor);

      clang::Cursor referenced = ref->referencedEntity->cursor;
      referenced = referenced.template_specialization_to_template_definition();

      IndexVarId var_id = db->ToVarId(referenced.get_usr());
      IndexVar* var = db->Resolve(var_id);
      UniqueAdd(var->uses, loc_spelling);
      break;
    }

    case CXIdxEntity_CXXConversionFunction:
    case CXIdxEntity_CXXStaticMethod:
    case CXIdxEntity_CXXInstanceMethod:
    case CXIdxEntity_Function:
    case CXIdxEntity_CXXConstructor:
    case CXIdxEntity_CXXDestructor: {
      // TODO: Redirect container to constructor for the following example, ie,
      //       we should be inserting an outgoing function call from the Foo
      //       ctor.
      //
      //  int Gen() { return 5; }
      //  class Foo {
      //    int x = Gen();
      //  }

      // TODO: search full history?
      Range loc_spelling = ResolveSpelling(ref->cursor);

      IndexFuncId called_id = db->ToFuncId(ref->referencedEntity->USR);
      IndexFunc* called = db->Resolve(called_id);

      // libclang doesn't provide a nice api to check if the given function
      // call is implicit. ref->kind should probably work (it's either direct
      // or implicit), but libclang only supports implicit for objective-c.
      bool is_implicit = CanBeCalledImplicitly(ref->referencedEntity->kind) &&
                         !CursorSpellingContainsString(ref->cursor, param->tu->cx_tu, called->def.short_name);

      if (IsFunctionCallContext(ref->container->cursor.kind)) {
        IndexFuncId caller_id = db->ToFuncId(ref->container->cursor);
        IndexFunc* caller = db->Resolve(caller_id);
        // Calling db->ToFuncId invalidates the FuncDef* ptrs.
        called = db->Resolve(called_id);

        AddFuncRef(&caller->def.callees, IndexFuncRef(called_id, loc_spelling, is_implicit));
        AddFuncRef(&called->callers, IndexFuncRef(caller_id, loc_spelling, is_implicit));
      } else {
        AddFuncRef(&called->callers, IndexFuncRef(loc_spelling, is_implicit));
      }

      break;
    }

    case CXIdxEntity_Typedef:
    case CXIdxEntity_CXXTypeAlias:
    case CXIdxEntity_Enum:
    case CXIdxEntity_Union:
    case CXIdxEntity_Struct:
    case CXIdxEntity_CXXClass: {
      clang::Cursor referenced_cursor = ref->referencedEntity->cursor;
      referenced_cursor = referenced_cursor.template_specialization_to_template_definition();
      IndexTypeId referenced_id = db->ToTypeId(referenced_cursor.get_usr());

      IndexType* referenced = db->Resolve(referenced_id);

      //
      // The following will generate two TypeRefs to Foo, both located at the
      // same spot (line 3, column 3). One of the parents will be set to
      // CXIdxEntity_Variable, the other will be CXIdxEntity_Function. There
      // does not appear to be a good way to disambiguate these references, as
      // using parent type alone breaks other indexing tasks.
      //
      // To work around this, we check to see if the usage location has been
      // inserted into all_uses previously.
      //
      //  struct Foo {};
      //  void Make() {
      //    Foo f;
      //  }
      //
      UniqueAdd(referenced->uses, ResolveSpelling(ref->cursor));
      break;
    }

    default:
      std::cerr
          << "!! Unhandled indexEntityReference: " << cursor.ToString()
          << " at "
          << ResolveSpelling(ref->cursor).start.ToString()
          << std::endl;
      std::cerr << "     ref->referencedEntity->kind = "
                << ref->referencedEntity->kind << std::endl;
      if (ref->parentEntity)
        std::cerr << "     ref->parentEntity->kind = "
                  << ref->parentEntity->kind << std::endl;
      std::cerr
          << "     ref->loc          = "
          << ResolveSpelling(ref->cursor).start.ToString()
          << std::endl;
      std::cerr << "     ref->kind         = " << ref->kind << std::endl;
      if (ref->parentEntity)
        std::cerr << "     parentEntity      = "
                  << clang::Cursor(ref->parentEntity->cursor).ToString()
                  << std::endl;
      if (ref->referencedEntity)
        std::cerr << "     referencedEntity  = "
                  << clang::Cursor(ref->referencedEntity->cursor).ToString()
                  << std::endl;
      if (ref->container)
        std::cerr << "     container         = "
                  << clang::Cursor(ref->container->cursor).ToString()
                  << std::endl;
      break;
  }
}































std::vector<std::unique_ptr<IndexFile>> Parse(
    Config* config, FileConsumer::SharedState* file_consumer_shared,
    std::string file,
    std::vector<std::string> args,
    const std::string& file_contents_path,
    const optional<std::string>& file_contents,
    PerformanceImportFile* perf,
    clang::Index* index,
    bool dump_ast) {

  if (!config->enableIndexing)
    return {};

  file = NormalizePath(file);

  Timer timer;

  //clang::Index index(0 /*excludeDeclarationsFromPCH*/,
  //                   0 /*displayDiagnostics*/);

  std::vector<CXUnsavedFile> unsaved_files;
  if (file_contents) {
    CXUnsavedFile unsaved;
    unsaved.Filename = file_contents_path.c_str();
    unsaved.Contents = file_contents->c_str();
    unsaved.Length = (unsigned long)file_contents->size();
    unsaved_files.push_back(unsaved);
  }
  clang::TranslationUnit tu(index, file, args, unsaved_files, CXTranslationUnit_KeepGoing | CXTranslationUnit_DetailedPreprocessingRecord);

  perf->index_parse = timer.ElapsedMicrosecondsAndReset();

  if (dump_ast)
    Dump(tu.document_cursor());


  IndexerCallbacks callbacks[] = {
      {&abortQuery, &diagnostic, &enteredMainFile, &ppIncludedFile,
       &importedASTFile, &startedTranslationUnit, &indexDeclaration,
       &indexEntityReference}
  };

  FileConsumer file_consumer(file_consumer_shared);
  IndexParam param(&tu, &file_consumer);

  CXFile cx_file = clang_getFile(tu.cx_tu, file.c_str());
  param.primary_file = ConsumeFile(&param, cx_file);

  //std::cerr << "!! [START] Indexing " << file << std::endl;
  CXIndexAction index_action = clang_IndexAction_create(index->cx_index);
  clang_indexTranslationUnit(index_action, &param, callbacks, sizeof(callbacks),
                             CXIndexOpt_IndexFunctionLocalSymbols | CXIndexOpt_SkipParsedBodiesInSession | CXIndexOpt_IndexImplicitTemplateInstantiations,
                             tu.cx_tu);
  clang_IndexAction_dispose(index_action);
  //std::cerr << "!! [END] Indexing " << file << std::endl;

  tu.document_cursor().VisitChildren(&VisitMacroDefinitionAndExpansions, &param);

  perf->index_build = timer.ElapsedMicrosecondsAndReset();

  auto result = param.file_consumer->TakeLocalState();
  for (auto& entry : result) {
    entry->last_modification_time = GetLastModificationTime(entry->path);
    entry->import_file = file;
    entry->args = args;
  }

  return result;
}


void IndexInit() {
  clang_enableStackTraces();
  clang_toggleCrashRecovery(1);
}