SwiftEditorInterfaceGen.cpp

//===--- SwiftEditorIntefaceGen.cpp ---------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//

#include "SwiftLangSupport.h"
#include "SwiftInterfaceGenContext.h"
#include "SwiftASTManager.h"

#include "swift/AST/ASTPrinter.h"
#include "swift/AST/ASTWalker.h"
#include "swift/Frontend/Frontend.h"
#include "swift/Frontend/PrintingDiagnosticConsumer.h"
#include "swift/IDE/ModuleInterfacePrinting.h"
#include "swift/IDE/SyntaxModel.h"
#include "swift/IDE/Utils.h"
#include "swift/Strings.h"

#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/ConvertUTF.h"

using namespace SourceKit;
using namespace swift;
using namespace ide;

class SwiftInterfaceGenContext::Implementation {
public:
  struct TextRange {
    unsigned Offset;
    unsigned Length;
  };

  struct TextReference {
    /// The declaration from the module.
    const ValueDecl *Dcl = nullptr;
    const ModuleEntity Mod;
    TextRange Range;

    TextReference(const ValueDecl *D, unsigned Offset, unsigned Length)
      : Dcl(D), Mod(), Range{Offset, Length} {}
    TextReference(const ModuleEntity Mod, unsigned Offset, unsigned Length)
    : Mod(Mod), Range{Offset, Length} {}
  };

  struct TextDecl {
    /// The declaration from the module.
    const Decl *Dcl = nullptr;
    /// The range in the interface source.
    TextRange Range;

    TextDecl(const Decl *D, TextRange Range)
      : Dcl(D), Range(Range) {}
    TextDecl() = default;
  };

  struct SourceTextInfo {
    std::string Text;
    std::vector<TextReference> References;
    std::vector<TextDecl> Decls;
    llvm::StringMap<TextDecl> USRMap;
  };

  // Hold an AstUnit so that the Decl* we have are always valid.
  ASTUnitRef AstUnit;
  std::string DocumentName;
  bool IsModule = false;
  std::string ModuleOrHeaderName;
  CompilerInvocation Invocation;
  PrintingDiagnosticConsumer DiagConsumer;
  CompilerInstance Instance;
  Module *Mod = nullptr;
  SourceTextInfo Info;
  // This is the non-typechecked AST for the generated interface source.
  CompilerInstance TextCI;
};

typedef SwiftInterfaceGenContext::Implementation::TextRange TextRange;
typedef SwiftInterfaceGenContext::Implementation::TextReference TextReference;
typedef SwiftInterfaceGenContext::Implementation::TextDecl TextDecl;
typedef SwiftInterfaceGenContext::Implementation::SourceTextInfo SourceTextInfo;

static Module *getModuleByFullName(ASTContext &Ctx, StringRef ModuleName) {
  SmallVector<std::pair<Identifier, SourceLoc>, 4>
      AccessPath;
  while (!ModuleName.empty()) {
    StringRef SubModuleName;
    std::tie(SubModuleName, ModuleName) = ModuleName.split('.');
    AccessPath.push_back({ Ctx.getIdentifier(SubModuleName), SourceLoc() });
  }
  return Ctx.getModule(AccessPath);
}

static Module *getModuleByFullName(ASTContext &Ctx, Identifier ModuleName) {
  return Ctx.getModule(std::make_pair(ModuleName, SourceLoc()));
}

namespace {
class AnnotatingPrinter : public StreamPrinter {
  SourceTextInfo &Info;

  struct DeclUSR {
    const Decl *Dcl = nullptr;
    std::string USR;
    DeclUSR(const Decl *D, StringRef USR) : Dcl(D), USR(USR) {}
  };
  std::vector<DeclUSR> DeclUSRs;

public:
  AnnotatingPrinter(SourceTextInfo &Info, llvm::raw_ostream &OS)
    : StreamPrinter(OS), Info(Info) { }

  ~AnnotatingPrinter() {
    assert(DeclUSRs.empty() && "unmatched printDeclLoc call ?");
  }

  void printDeclLoc(const Decl *D) override {
    unsigned LocOffset = OS.tell();
    TextDecl Entry(D, TextRange{LocOffset, 0});
    Info.Decls.emplace_back(Entry);

    if (auto VD = dyn_cast<ValueDecl>(D)) {
      // Only record non-local USRs.
      if (D->getDeclContext()->getLocalContext())
        return;

      llvm::SmallString<64> Buf;
      llvm::raw_svector_ostream OS(Buf);
      if (!SwiftLangSupport::printUSR(VD, OS)) {
        StringRef USR = OS.str();
        Info.USRMap[USR] = Entry;
        DeclUSRs.emplace_back(VD, USR);
      }
    }
  }

  void printDeclNameEndLoc(const Decl *D) override {
    unsigned Offset = OS.tell();

    if (!Info.Decls.empty() && Info.Decls.back().Dcl == D) {
      TextDecl &Entry = Info.Decls.back();
      Entry.Range.Length = Offset - Entry.Range.Offset;
    }

    if (!DeclUSRs.empty() && DeclUSRs.back().Dcl == D) {
      TextDecl &Entry = Info.USRMap[DeclUSRs.back().USR];
      assert(Entry.Dcl == D);
      Entry.Range.Length = Offset - Entry.Range.Offset;
      DeclUSRs.pop_back();
    }
  }

  void printTypeRef(const TypeDecl *TD, Identifier Name) override {
    unsigned StartOffset = OS.tell();
    Info.References.emplace_back(TD, StartOffset, Name.str().size());
    StreamPrinter::printTypeRef(TD, Name);
  }

  void printModuleRef(ModuleEntity Mod, Identifier Name) override {
    unsigned StartOffset = OS.tell();
    Info.References.emplace_back(Mod, StartOffset, Name.str().size());
    StreamPrinter::printModuleRef(Mod, Name);
  }
};

class DocSyntaxWalker : public SyntaxModelWalker {
  SourceManager &SM;
  unsigned BufferID;
  EditorConsumer &Consumer;

public:
  DocSyntaxWalker(SourceManager &SM, unsigned BufferID,
                  EditorConsumer &Consumer)
    : SM(SM), BufferID(BufferID), Consumer(Consumer) {}

  bool walkToNodePre(SyntaxNode Node) override {
    unsigned Offset = SM.getLocOffsetInBuffer(Node.Range.getStart(), BufferID);
    unsigned Length = Node.Range.getByteLength();

    UIdent UID = SwiftLangSupport::getUIDForSyntaxNodeKind(Node.Kind);
    if (UID.isValid())
      Consumer.handleSyntaxMap(Offset, Length, UID);
    return true;
  }
};

}

static bool makeParserAST(CompilerInstance &CI, StringRef Text) {
  CompilerInvocation Invocation;
  Invocation.setModuleName("main");
  Invocation.setInputKind(InputFileKind::IFK_Swift);

  std::unique_ptr<llvm::MemoryBuffer> Buf;
  Buf = llvm::MemoryBuffer::getMemBuffer(Text, "<module-interface>");
  Invocation.addInputBuffer(Buf.get());
  if (CI.setup(Invocation))
    return true;
  CI.performParseOnly();
  return false;
}

static void reportSyntacticAnnotations(CompilerInstance &CI,
                                       EditorConsumer &Consumer) {
  auto SF = dyn_cast<SourceFile>(CI.getMainModule()->getFiles()[0]);
  SyntaxModelContext SyntaxContext(*SF);
  DocSyntaxWalker SyntaxWalker(CI.getSourceMgr(), *SF->getBufferID(),
                               Consumer);
  SyntaxContext.walk(SyntaxWalker);
}

static void reportDocumentStructure(CompilerInstance &CI,
                                    EditorConsumer &Consumer) {
  auto SF = dyn_cast<SourceFile>(CI.getMainModule()->getFiles()[0]);
  SwiftEditorDocument::reportDocumentStructure(*SF, Consumer);
}

static void reportSemanticAnnotations(const SourceTextInfo &IFaceInfo,
                                      EditorConsumer &Consumer) {
  for (auto &Ref : IFaceInfo.References) {
    UIdent Kind;
    bool IsSystem;
    if (Ref.Mod) {
      Kind = SwiftLangSupport::getUIDForModuleRef();
      IsSystem = Ref.Mod.isSystemModule();
    } else if (Ref.Dcl) {
      Kind = SwiftLangSupport::getUIDForDecl(Ref.Dcl, /*IsRef=*/true);
      IsSystem = Ref.Dcl->getModuleContext()->isSystemModule();
    }
    if (Kind.isInvalid())
      continue;
    unsigned Offset = Ref.Range.Offset;
    unsigned Length = Ref.Range.Length;
    Consumer.handleSemanticAnnotation(Offset, Length, Kind, IsSystem);
  }
}

static bool getModuleInterfaceInfo(ASTContext &Ctx,
                                   StringRef ModuleName,
                                 SwiftInterfaceGenContext::Implementation &Impl,
                                   std::string &ErrMsg) {
  Module *&Mod = Impl.Mod;
  SourceTextInfo &Info = Impl.Info;

  if (ModuleName.empty()) {
    ErrMsg = "Module name is empty";
    return true;
  }

  // Get the (sub)module to generate.
  Mod = getModuleByFullName(Ctx, ModuleName);
  if (!Mod) {
    ErrMsg = "Could not load module: ";
    ErrMsg += ModuleName;
    return true;
  }

  std::vector<StringRef> SplitModuleName;
  while (!ModuleName.empty()) {
    StringRef SubModuleName;
    std::tie(SubModuleName, ModuleName) = ModuleName.split('.');
    SplitModuleName.push_back(SubModuleName);
  }
  assert(!SplitModuleName.empty());

  // FIXME: If this is a submodule, get its top-level module, which will be the
  // DeclContext for all of its Decls since we don't have first-class submodules.
  if (SplitModuleName.size() > 1) {
    Mod = getModuleByFullName(Ctx, SplitModuleName[0]);
    if (!Mod) {
      ErrMsg = "Could not load module: ";
      ErrMsg += ModuleName;
      return true;
    }
  }

  PrintOptions Options = PrintOptions::printInterface();
  ModuleTraversalOptions TraversalOptions = None; // Don't print submodules.
  SmallString<128> Text;
  llvm::raw_svector_ostream OS(Text);
  AnnotatingPrinter Printer(Info, OS);
  printSubmoduleInterface(Mod, SplitModuleName,
                          TraversalOptions,
                          Printer, Options);

  Info.Text = OS.str();
  return false;
}

static bool getHeaderInterfaceInfo(ASTContext &Ctx,
                                   StringRef HeaderName,
                                   SourceTextInfo &Info,
                                   std::string &ErrMsg) {
  if (HeaderName.empty()) {
    ErrMsg = "Header name is empty";
    return true;
  }

  PrintOptions Options = PrintOptions::printInterface();

  SmallString<128> Text;
  llvm::raw_svector_ostream OS(Text);
  AnnotatingPrinter Printer(Info, OS);
  printHeaderInterface(HeaderName, Ctx, Printer, Options);

  Info.Text = OS.str();
  return false;
}

SwiftInterfaceGenContextRef
SwiftInterfaceGenContext::createForSwiftSource(StringRef DocumentName,
                                               StringRef SourceFileName,
                                               ASTUnitRef AstUnit,
                                               std::string &ErrMsg) {
  SwiftInterfaceGenContextRef IFaceGenCtx{ new SwiftInterfaceGenContext() };
  IFaceGenCtx->Impl.DocumentName = DocumentName;
  IFaceGenCtx->Impl.IsModule = true;
  IFaceGenCtx->Impl.ModuleOrHeaderName = SourceFileName;
  IFaceGenCtx->Impl.AstUnit = AstUnit;

  PrintOptions Options = PrintOptions::printSwiftFileInterface();
  SmallString<128> Text;
  llvm::raw_svector_ostream OS(Text);
  AnnotatingPrinter Printer(IFaceGenCtx->Impl.Info, OS);
  printSwiftSourceInterface(AstUnit->getPrimarySourceFile(), Printer, Options);
  IFaceGenCtx->Impl.Info.Text = OS.str();
  if (makeParserAST(IFaceGenCtx->Impl.TextCI, IFaceGenCtx->Impl.Info.Text)) {
    ErrMsg = "Error during syntactic parsing";
    return nullptr;
  }
  return IFaceGenCtx;
}

SwiftInterfaceGenContextRef
SwiftInterfaceGenContext::create(StringRef DocumentName,
                                 bool IsModule,
                                 StringRef ModuleOrHeaderName,
                                 CompilerInvocation Invocation,
                                 std::string &ErrMsg) {
  SwiftInterfaceGenContextRef IFaceGenCtx{ new SwiftInterfaceGenContext() };
  IFaceGenCtx->Impl.DocumentName = DocumentName;
  IFaceGenCtx->Impl.IsModule = IsModule;
  IFaceGenCtx->Impl.ModuleOrHeaderName = ModuleOrHeaderName;
  IFaceGenCtx->Impl.Invocation = Invocation;
  CompilerInstance &CI = IFaceGenCtx->Impl.Instance;

  // Display diagnostics to stderr.
  CI.addDiagnosticConsumer(&IFaceGenCtx->Impl.DiagConsumer);

  Invocation.clearInputs();
  if (CI.setup(Invocation)) {
    ErrMsg = "Error during invocation setup";
    return nullptr;
  }

  ASTContext &Ctx = CI.getASTContext();
  CloseClangModuleFiles scopedCloseFiles(*Ctx.getClangModuleLoader());

  // Load standard library so that Clang importer can use it.
  auto *Stdlib = getModuleByFullName(Ctx, Ctx.StdlibModuleName);
  if (!Stdlib) {
    ErrMsg = "Could not load the stdlib module";
    return nullptr;
  }

  if (IsModule) {
    if (getModuleInterfaceInfo(Ctx, ModuleOrHeaderName, IFaceGenCtx->Impl,
                               ErrMsg))
      return nullptr;
  } else {
    auto &FEOpts = Invocation.getFrontendOptions();
    if (FEOpts.ImplicitObjCHeaderPath.empty()) {
      ErrMsg = "Implicit ObjC header path is empty";
      return nullptr;
    }

    auto &Importer = static_cast<ClangImporter &>(*Ctx.getClangModuleLoader());
    Importer.importBridgingHeader(FEOpts.ImplicitObjCHeaderPath,
                                  CI.getMainModule(),
                                  /*diagLoc=*/{},
                                  /*trackParsedSymbols=*/true);
    if (getHeaderInterfaceInfo(Ctx, ModuleOrHeaderName,
                               IFaceGenCtx->Impl.Info, ErrMsg))
      return nullptr;
  }

  if (makeParserAST(IFaceGenCtx->Impl.TextCI, IFaceGenCtx->Impl.Info.Text)) {
    ErrMsg = "Error during syntactic parsing";
    return nullptr;
  }

  return IFaceGenCtx;
}

SwiftInterfaceGenContext::SwiftInterfaceGenContext()
  : Impl(*new Implementation) {
}
SwiftInterfaceGenContext::~SwiftInterfaceGenContext() {
  delete &Impl;
}

StringRef SwiftInterfaceGenContext::getDocumentName() const {
  return Impl.DocumentName;
}

StringRef SwiftInterfaceGenContext::getModuleOrHeaderName() const {
  return Impl.ModuleOrHeaderName;
}

bool SwiftInterfaceGenContext::isModule() const {
  return Impl.IsModule;
}

bool SwiftInterfaceGenContext::matches(StringRef ModuleName,
                                       const swift::CompilerInvocation &Invok) {
  if (!Impl.IsModule)
    return false;
  if (ModuleName != Impl.ModuleOrHeaderName)
    return false;

  if (Invok.getTargetTriple() != Impl.Invocation.getTargetTriple())
    return false;

  if (ModuleName == STDLIB_NAME)
    return true;

  if (Invok.getSDKPath() != Impl.Invocation.getSDKPath())
    return false;

  if (Impl.Mod->isSystemModule())
    return true;

  const SearchPathOptions &SPOpts = Invok.getSearchPathOptions();
  const SearchPathOptions &ImplSPOpts = Impl.Invocation.getSearchPathOptions();
  if (SPOpts.ImportSearchPaths != ImplSPOpts.ImportSearchPaths)
    return false;
  if (SPOpts.FrameworkSearchPaths != ImplSPOpts.FrameworkSearchPaths)
    return false;

  if (Invok.getClangImporterOptions().ExtraArgs !=
      Impl.Invocation.getClangImporterOptions().ExtraArgs)
    return false;

  return true;
}

void SwiftInterfaceGenContext::reportEditorInfo(EditorConsumer &Consumer) const {
  Consumer.handleSourceText(Impl.Info.Text);
  reportSyntacticAnnotations(Impl.TextCI, Consumer);
  reportDocumentStructure(Impl.TextCI, Consumer);
  reportSemanticAnnotations(Impl.Info, Consumer);
  Consumer.finished();
}

SwiftInterfaceGenContext::ResolvedEntity
SwiftInterfaceGenContext::resolveEntityForOffset(unsigned Offset) const {
  // Search among the references.
  {
    auto Pos = std::upper_bound(Impl.Info.References.begin(),
                                Impl.Info.References.end(),
                                Offset,
      [&](unsigned Offset, const TextReference &RHS) -> bool {
        return Offset < RHS.Range.Offset+RHS.Range.Length;
      });
    if (Pos != Impl.Info.References.end() && Pos->Range.Offset <= Offset) {
      if (Pos->Mod)
        return ResolvedEntity(Pos->Mod, true);
      else
        return ResolvedEntity(Pos->Dcl, true);
    }
  }

  SourceManager &SM = Impl.TextCI.getSourceMgr();
  auto SF = dyn_cast<SourceFile>(Impl.TextCI.getMainModule()->getFiles()[0]);
  unsigned BufferID = *SF->getBufferID();
  SourceLoc Loc = Lexer::getLocForStartOfToken(SM, BufferID, Offset);
  Offset = SM.getLocOffsetInBuffer(Loc, BufferID);

  // Search among the declarations.
  {
    auto Pos = std::lower_bound(Impl.Info.Decls.begin(),
                                Impl.Info.Decls.end(),
                                Offset,
      [&](const TextDecl &LHS, unsigned Offset) -> bool {
        return LHS.Range.Offset < Offset;
      });
    if (Pos != Impl.Info.Decls.end() && Pos->Range.Offset == Offset)
      return ResolvedEntity(dyn_cast<ValueDecl>(Pos->Dcl), false);
  }

  return ResolvedEntity();
}

llvm::Optional<std::pair<unsigned, unsigned>>
SwiftInterfaceGenContext::findUSRRange(StringRef USR) const {
  auto Pos = Impl.Info.USRMap.find(USR);
  if (Pos == Impl.Info.USRMap.end())
    return None;

  return std::make_pair(Pos->getValue().Range.Offset,
                        Pos->getValue().Range.Length);
}

void SwiftInterfaceGenContext::applyTo(
    swift::CompilerInvocation &CompInvok) const {
  CompInvok = Impl.Invocation;
}

SwiftInterfaceGenContextRef SwiftInterfaceGenMap::get(StringRef Name) const {
  llvm::sys::ScopedLock L(Mtx);
  auto It = IFaceGens.find(Name);
  if (It == IFaceGens.end())
    return nullptr;
  return It->second;
}

void SwiftInterfaceGenMap::set(StringRef Name,
                               SwiftInterfaceGenContextRef IFaceGen) {
  llvm::sys::ScopedLock L(Mtx);
  IFaceGens[Name] = IFaceGen;
}

bool SwiftInterfaceGenMap::remove(StringRef Name) {
  llvm::sys::ScopedLock L(Mtx);
  return IFaceGens.erase(Name);
}

SwiftInterfaceGenContextRef
SwiftInterfaceGenMap::find(StringRef ModuleName,
                           const CompilerInvocation &Invok) {
  llvm::sys::ScopedLock L(Mtx);
  for (auto &Entry : IFaceGens) {
    if (Entry.getValue()->matches(ModuleName, Invok))
      return Entry.getValue();
  }
  return nullptr;
}

//============================================================================//
// EditorOpenInterface
//============================================================================//

void SwiftLangSupport::editorOpenInterface(EditorConsumer &Consumer,
                                           StringRef Name,
                                           StringRef ModuleName,
                                           ArrayRef<const char *> Args) {
  CompilerInstance CI;
  // Display diagnostics to stderr.
  PrintingDiagnosticConsumer PrintDiags;
  CI.addDiagnosticConsumer(&PrintDiags);

  CompilerInvocation Invocation;
  std::string Error;
  if (getASTManager().initCompilerInvocation(Invocation, Args, CI.getDiags(),
                                             StringRef(), Error)) {
    Consumer.handleRequestError(Error.c_str());
    return;
  }

  trace::TracedOperation TracedOp;
  if (trace::enabled()) {
    trace::SwiftInvocation SwiftArgs;
    SwiftArgs.Args.Args.assign(Args.begin(), Args.end());
    // NOTE: do not use primary file
    // NOTE: do not use files
    TracedOp.start(trace::OperationKind::OpenInterface, SwiftArgs,
                   {std::make_pair("Name", Name),
                    std::make_pair("ModuleName", ModuleName)});
  }

  Invocation.getClangImporterOptions().ImportForwardDeclarations = true;

  std::string ErrMsg;
  auto IFaceGenRef = SwiftInterfaceGenContext::create(Name,
                                                      /*IsModule=*/true,
                                                      ModuleName,
                                                      Invocation,
                                                      ErrMsg);
  if (!IFaceGenRef) {
    Consumer.handleRequestError(ErrMsg.c_str());
    return;
  }

  IFaceGenContexts.set(Name, IFaceGenRef);
  IFaceGenRef->reportEditorInfo(Consumer);
}

class PrimaryFileInterfaceConsumer : public SwiftASTConsumer {

  std::string Name;
  std::string SourceFileName;
  SwiftInterfaceGenMap &Contexts;
  std::shared_ptr<EditorConsumer> Consumer;

public:
  PrimaryFileInterfaceConsumer(StringRef Name, StringRef SourceFileName,
                               SwiftInterfaceGenMap &Contexts,
                               std::shared_ptr<EditorConsumer> Consumer) :
    Name(Name), SourceFileName(SourceFileName), Contexts(Contexts),
      Consumer(Consumer) {}

  void failed(StringRef Error) override {
    Consumer->handleRequestError(Error.data());
  }

  void handlePrimaryAST(ASTUnitRef AstUnit) override {
    std::string Error;
    auto IFaceGenRef = SwiftInterfaceGenContext::createForSwiftSource(Name,
      SourceFileName, AstUnit, Error);
    if (!Error.empty())
      Consumer->handleRequestError(Error.data());
    Contexts.set(Name, IFaceGenRef);
    IFaceGenRef->reportEditorInfo(*Consumer);
  }
};

void SwiftLangSupport::editorOpenSwiftSourceInterface(StringRef Name,
                                                      StringRef SourceName,
                                                      ArrayRef<const char *> Args,
                                                      std::shared_ptr<EditorConsumer> Consumer) {
  std::string Error;
  auto Invocation = ASTMgr->getInvocation(Args, SourceName, Error);
  if (!Invocation) {
    Consumer->handleRequestError(Error.c_str());
    return;
  }
  trace::TracedOperation TracedOp;
  if (trace::enabled()) {
    trace::SwiftInvocation SwiftArgs;
    SwiftArgs.Args.Args.assign(Args.begin(), Args.end());
    // NOTE: do not use primary file
    // NOTE: do not use files
    TracedOp.start(trace::OperationKind::OpenInterface, SwiftArgs,
                   {std::make_pair("Name", Name),
                     std::make_pair("SourceName", SourceName)});
  }
  auto AstConsumer = std::make_shared<PrimaryFileInterfaceConsumer>(Name,
    SourceName, IFaceGenContexts, Consumer);
  static const char OncePerASTToken = 0;
  getASTManager().processASTAsync(Invocation, AstConsumer, &OncePerASTToken);
}

void SwiftLangSupport::editorOpenHeaderInterface(EditorConsumer &Consumer,
                                                 StringRef Name,
                                                 StringRef HeaderName,
                                                 ArrayRef<const char *> Args) {
  CompilerInstance CI;
  // Display diagnostics to stderr.
  PrintingDiagnosticConsumer PrintDiags;
  CI.addDiagnosticConsumer(&PrintDiags);

  CompilerInvocation Invocation;
  std::string Error;
  if (getASTManager().initCompilerInvocation(Invocation, llvm::None, CI.getDiags(),
                                             StringRef(), Error)) {
    Consumer.handleRequestError(Error.c_str());
    return;
  }

  if (initInvocationByClangArguments(Args, Invocation, Error)) {
    Consumer.handleRequestError(Error.c_str());
    return;
  }

  trace::TracedOperation TracedOp;
  if (trace::enabled()) {
    trace::SwiftInvocation SwiftArgs;
    SwiftArgs.Args.Args.assign(Args.begin(), Args.end());
    // NOTE: do not use primary file
    // NOTE: do not use files
    TracedOp.start(trace::OperationKind::OpenHeaderInterface, SwiftArgs,
                   {std::make_pair("Name", Name),
                    std::make_pair("HeaderName", HeaderName)});
  }

  Invocation.getClangImporterOptions().ImportForwardDeclarations = true;
  auto IFaceGenRef = SwiftInterfaceGenContext::create(Name,
                                                      /*IsModule=*/false,
                                                      HeaderName,
                                                      Invocation,
                                                      Error);
  if (!IFaceGenRef) {
    Consumer.handleRequestError(Error.c_str());
    return;
  }

  IFaceGenContexts.set(Name, IFaceGenRef);
  IFaceGenRef->reportEditorInfo(Consumer);
}

void SwiftLangSupport::findInterfaceDocument(StringRef ModuleName,
                                             ArrayRef<const char *> Args,
                       std::function<void(const InterfaceDocInfo &)> Receiver) {
  InterfaceDocInfo Info;

  CompilerInstance CI;
  // Display diagnostics to stderr.
  PrintingDiagnosticConsumer PrintDiags;
  CI.addDiagnosticConsumer(&PrintDiags);

  CompilerInvocation Invocation;
  std::string Error;
  if (getASTManager().initCompilerInvocation(Invocation, Args, CI.getDiags(),
                                             StringRef(), Error)) {
    Info.Error = Error;
    return Receiver(Info);
  }

  if (auto IFaceGenRef = IFaceGenContexts.find(ModuleName, Invocation))
    Info.ModuleInterfaceName = IFaceGenRef->getDocumentName();

  SmallString<128> Buf;
  SmallVector<std::pair<unsigned, unsigned>, 16> ArgOffs;
  auto addArgPair = [&](StringRef Arg, StringRef Val) {
    assert(!Arg.empty());
    if (Val.empty())
      return;
    unsigned ArgBegin = Buf.size();
    Buf += Arg;
    unsigned ArgEnd = Buf.size();
    unsigned ValBegin = Buf.size();
    Buf += Val;
    unsigned ValEnd = Buf.size();
    ArgOffs.push_back(std::make_pair(ArgBegin, ArgEnd));
    ArgOffs.push_back(std::make_pair(ValBegin, ValEnd));
  };
  auto addSingleArg = [&](StringRef Arg) {
    assert(!Arg.empty());
    unsigned ArgBegin = Buf.size();
    Buf += Arg;
    unsigned ArgEnd = Buf.size();
    ArgOffs.push_back(std::make_pair(ArgBegin, ArgEnd));
  };

  addArgPair("-target", Invocation.getTargetTriple());

  const auto &SPOpts = Invocation.getSearchPathOptions();
  addArgPair("-sdk", SPOpts.SDKPath);
  for (auto &Path : SPOpts.FrameworkSearchPaths)
    addArgPair("-F", Path);
  for (auto &Path : SPOpts.ImportSearchPaths)
    addArgPair("-I", Path);

  const auto &ClangOpts = Invocation.getClangImporterOptions();
  addArgPair("-module-cache-path", ClangOpts.ModuleCachePath);
  for (auto &ExtraArg : ClangOpts.ExtraArgs)
    addArgPair("-Xcc", ExtraArg);

  if (Invocation.getFrontendOptions().ImportUnderlyingModule)
    addSingleArg("-import-underlying-module");
  addArgPair("-import-objc-header",
             Invocation.getFrontendOptions().ImplicitObjCHeaderPath);

  SmallVector<StringRef, 16> NewArgs;
  for (auto Pair : ArgOffs) {
    NewArgs.push_back(StringRef(Buf.begin()+Pair.first, Pair.second-Pair.first));
  }
  Info.CompilerArgs = NewArgs;

  return Receiver(Info);
}