//===-- Frontend.cpp - frontend utility methods ---------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file contains utility methods for parsing and performing semantic
// on modules.
//
//===----------------------------------------------------------------------===//

#include "swift/Frontend/Frontend.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/Component.h"
#include "swift/AST/Diagnostics.h"
#include "swift/AST/Module.h"
#include "swift/Parse/DelayedParsingCallbacks.h"
#include "swift/Parse/Lexer.h"
#include "swift/SIL/SILModule.h"
#include "swift/Serialization/SerializedModuleLoader.h"
#include "swift/Subsystems.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/SourceMgr.h"

using namespace swift;

swift::CompilerInvocation::CompilerInvocation() {
  TargetTriple = llvm::sys::getDefaultTargetTriple();
}

std::string swift::CompilerInvocation::getRuntimeIncludePath() const {
  llvm::SmallString<128> LibPath(MainExecutablePath);
  llvm::sys::path::remove_filename(LibPath); // Remove /swift
  llvm::sys::path::remove_filename(LibPath); // Remove /bin
  llvm::sys::path::append(LibPath, "lib", "swift");
  return LibPath.str();
}

void swift::CompilerInstance::createSILModule() {
  TheSILModule.reset(SILModule::createEmptyModule(getASTContext()));
}

bool swift::CompilerInstance::setup(const CompilerInvocation &Invok) {
  Invocation = Invok;

  Context.reset(new ASTContext(Invocation.getLangOptions(), SourceMgr, Diagnostics));

  // Give the context the list of search paths to use for modules.
  Context->ImportSearchPaths = Invocation.getImportSearchPaths();
  Context->addModuleLoader(SourceLoader::create(*Context));
  Context->addModuleLoader(SerializedModuleLoader::create(*Context));

  // If the user has specified an SDK, wire up the Clang module importer
  // and point it at that SDK.
  if (!Invocation.getSDKPath().empty()) {
    auto ImporterCtor = Invocation.getClangImporterCtor();
    assert(ImporterCtor && "SDK patch can't be empty without importer set!");
    auto clangImporter =
        ImporterCtor(*Context, Invocation.getSDKPath(),
                     Invocation.getTargetTriple(),
                     Invocation.getClangModuleCachePath(),
                     Invocation.getImportSearchPaths());
    if (!clangImporter) {
      Diagnostics.diagnose(SourceLoc(), diag::error_clang_importer_create_fail);
      return true;
    }

    Context->addModuleLoader(clangImporter, /*isClang*/true);
  }

  // Add the runtime include path (which contains swift.swift)
  Context->ImportSearchPaths.push_back(Invocation.getRuntimeIncludePath());

  assert(Lexer::isIdentifier(Invocation.getModuleName()));

  if (Invocation.getTUKind() == TranslationUnit::SIL)
    createSILModule();

  auto CodeCompletePoint = Invocation.getCodeCompletionPoint();
  if (CodeCompletePoint.first) {
    auto MemBuf = CodeCompletePoint.first;
    // CompilerInvocation doesn't own the buffers, copy to a new buffer.
    llvm::MemoryBuffer *CodeCompletionBuffer =
        llvm::MemoryBuffer::getMemBufferCopy(MemBuf->getBuffer(),
                                             MemBuf->getBufferIdentifier());
    CodeCompletionBufferID = SourceMgr.AddNewSourceBuffer(CodeCompletionBuffer,
                                                          llvm::SMLoc());
    BufferIDs.push_back(CodeCompletionBufferID);
    CodeCompleteLoc = SourceLoc(llvm::SMLoc::getFromPointer(
        CodeCompletionBuffer->getBufferStart() + CodeCompletePoint.second));
  }

  for (auto &File : Invocation.getInputFilenames()) {
    // Open the input file.
    llvm::OwningPtr<llvm::MemoryBuffer> InputFile;
    if (llvm::error_code Err =
          llvm::MemoryBuffer::getFileOrSTDIN(File, InputFile)) {
      Diagnostics.diagnose(SourceLoc(), diag::error_open_input_file,
                           File, Err.message());
      return true;
    }
    // Transfer ownership of the MemoryBuffer to the SourceMgr.
    BufferIDs.push_back(SourceMgr.AddNewSourceBuffer(InputFile.take(),
                                                     llvm::SMLoc()));
  }

  for (auto Buf : Invocation.getInputBuffers()) {
    // CompilerInvocation doesn't own the buffers, copy to a new buffer.
    BufferIDs.push_back(SourceMgr.AddNewSourceBuffer(
        llvm::MemoryBuffer::getMemBufferCopy(Buf->getBuffer(),
                                             Buf->getBufferIdentifier()),
                                                     llvm::SMLoc()));
  }

  return false;
}

void swift::CompilerInstance::doIt() {
  const TranslationUnit::TUKind Kind = Invocation.getTUKind();
  Component *Comp = new (Context->Allocate<Component>(1)) Component();
  Identifier ID = Context->getIdentifier(Invocation.getModuleName());
  TU = new (*Context) TranslationUnit(ID, Comp, *Context, Kind);
  Context->LoadedModules[ID.str()] = TU;

  TU->HasBuiltinModuleAccess = Invocation.getParseStdlib();

  // If we're in SIL mode, don't auto import any libraries.
  // Also don't perform auto import if we are not going to do semantic
  // analysis.
  if (Kind != TranslationUnit::SIL && !Invocation.getParseOnly())
    performAutoImport(TU);

  std::unique_ptr<DelayedParsingCallbacks> DelayedCB;
  if (Invocation.isCodeCompletion()) {
    DelayedCB.reset(new CodeCompleteDelayedCallbacks(CodeCompleteLoc));
  } else if (Invocation.isDelayedFunctionBodyParsing()) {
    DelayedCB.reset(new AlwaysDelayedCallbacks);
  }

  PersistentParserState PersistentState;

  if (Kind == TranslationUnit::Library) {
    // Parse all of the files into one big translation unit.
    for (auto &BufferID : BufferIDs) {
      unsigned CodeCompletionOffset = ~0U;
      if (BufferID == CodeCompletionBufferID)
        CodeCompletionOffset = Invocation.getCodeCompletionPoint().second;
      bool Done;
      parseIntoTranslationUnit(TU, BufferID, &Done, CodeCompletionOffset,
                               nullptr, &PersistentState, DelayedCB.get());
      assert(Done && "Parser returned early?");
      (void) Done;
    }

    // Finally, if enabled, type check the whole thing in one go.
    if (!Invocation.getParseOnly())
      performTypeChecking(TU);

    if (DelayedCB) {
      performDelayedParsing(TU, PersistentState,
                            Invocation.getCodeCompletionFactory(),
                            Invocation.getCodeCompletionPoint().second);
    }
    return;
  }

  // This may only be a main module or SIL, which requires pumping the parser.
  assert(Kind == TranslationUnit::Main || Kind == TranslationUnit::SIL);
  assert(BufferIDs.size() == 1 && "This mode only allows one input");
  unsigned BufferID = BufferIDs[0];

  SILParserState SILContext(TheSILModule.get());

  unsigned CurTUElem = 0;
  bool Done;
  do {
    // Pump the parser multiple times if necessary.  It will return early
    // after parsing any top level code in a main module, or in SIL mode when
    // there are chunks of swift decls (e.g. imports and types) interspersed
    // with 'sil' definitions.
    parseIntoTranslationUnit(TU, BufferID, &Done,
                             Invocation.getCodeCompletionPoint().second,
                             TheSILModule ? &SILContext : nullptr,
                             &PersistentState, DelayedCB.get());
    if (!Invocation.getParseOnly())
      performTypeChecking(TU, CurTUElem);
    CurTUElem = TU->Decls.size();
  } while (!Done);

  if (DelayedCB) {
    performDelayedParsing(TU, PersistentState,
                          Invocation.getCodeCompletionFactory(),
                          Invocation.getCodeCompletionPoint().second);
  }
}