path: root/lib/Lex/HeaderSearch.cpp

//===--- HeaderSearch.cpp - Resolve Header File Locations ---===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements the DirectoryLookup and HeaderSearch interfaces.
//
//===----------------------------------------------------------------------===//

#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/HeaderMap.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/IdentifierTable.h"
#include "llvm/System/Path.h"
#include "llvm/ADT/SmallString.h"
#include <cstdio>
using namespace clang;

const IdentifierInfo *
HeaderFileInfo::getControllingMacro(ExternalIdentifierLookup *External) {
  if (ControllingMacro)
    return ControllingMacro;

  if (!ControllingMacroID || !External)
    return 0;

  ControllingMacro = External->GetIdentifier(ControllingMacroID);
  return ControllingMacro;
}

HeaderSearch::HeaderSearch(FileManager &FM, const FileSystemOptions &FSOpts)
    : FileMgr(FM), FileSystemOpts(FSOpts), FrameworkMap(64) {
  SystemDirIdx = 0;
  NoCurDirSearch = false;

  ExternalLookup = 0;
  NumIncluded = 0;
  NumMultiIncludeFileOptzn = 0;
  NumFrameworkLookups = NumSubFrameworkLookups = 0;
}

HeaderSearch::~HeaderSearch() {
  // Delete headermaps.
  for (unsigned i = 0, e = HeaderMaps.size(); i != e; ++i)
    delete HeaderMaps[i].second;
}

void HeaderSearch::PrintStats() {
  fprintf(stderr, "\n*** HeaderSearch Stats:\n");
  fprintf(stderr, "%d files tracked.\n", (int)FileInfo.size());
  unsigned NumOnceOnlyFiles = 0, MaxNumIncludes = 0, NumSingleIncludedFiles = 0;
  for (unsigned i = 0, e = FileInfo.size(); i != e; ++i) {
    NumOnceOnlyFiles += FileInfo[i].isImport;
    if (MaxNumIncludes < FileInfo[i].NumIncludes)
      MaxNumIncludes = FileInfo[i].NumIncludes;
    NumSingleIncludedFiles += FileInfo[i].NumIncludes == 1;
  }
  fprintf(stderr, "  %d #import/#pragma once files.\n", NumOnceOnlyFiles);
  fprintf(stderr, "  %d included exactly once.\n", NumSingleIncludedFiles);
  fprintf(stderr, "  %d max times a file is included.\n", MaxNumIncludes);

  fprintf(stderr, "  %d #include/#include_next/#import.\n", NumIncluded);
  fprintf(stderr, "    %d #includes skipped due to"
          " the multi-include optimization.\n", NumMultiIncludeFileOptzn);

  fprintf(stderr, "%d framework lookups.\n", NumFrameworkLookups);
  fprintf(stderr, "%d subframework lookups.\n", NumSubFrameworkLookups);
}

/// CreateHeaderMap - This method returns a HeaderMap for the specified
/// FileEntry, uniquing them through the the 'HeaderMaps' datastructure.
const HeaderMap *HeaderSearch::CreateHeaderMap(const FileEntry *FE) {
  // We expect the number of headermaps to be small, and almost always empty.
  // If it ever grows, use of a linear search should be re-evaluated.
  if (!HeaderMaps.empty()) {
    for (unsigned i = 0, e = HeaderMaps.size(); i != e; ++i)
      // Pointer equality comparison of FileEntries works because they are
      // already uniqued by inode.
      if (HeaderMaps[i].first == FE)
        return HeaderMaps[i].second;
  }

  if (const HeaderMap *HM = HeaderMap::Create(FE, FileMgr, FileSystemOpts)) {
    HeaderMaps.push_back(std::make_pair(FE, HM));
    return HM;
  }

  return 0;
}

//===----------------------------------------------------------------------===//
// File lookup within a DirectoryLookup scope
//===----------------------------------------------------------------------===//

/// getName - Return the directory or filename corresponding to this lookup
/// object.
const char *DirectoryLookup::getName() const {
  if (isNormalDir())
    return getDir()->getName();
  if (isFramework())
    return getFrameworkDir()->getName();
  assert(isHeaderMap() && "Unknown DirectoryLookup");
  return getHeaderMap()->getFileName();
}


/// LookupFile - Lookup the specified file in this search path, returning it
/// if it exists or returning null if not.
const FileEntry *DirectoryLookup::LookupFile(llvm::StringRef Filename,
                                             HeaderSearch &HS) const {
  llvm::SmallString<1024> TmpDir;
  if (isNormalDir()) {
    // Concatenate the requested file onto the directory.
    // FIXME: Portability.  Filename concatenation should be in sys::Path.
    TmpDir += getDir()->getName();
    TmpDir.push_back('/');
    TmpDir.append(Filename.begin(), Filename.end());
    return HS.getFileMgr().getFile(TmpDir.begin(), TmpDir.end(),
                                   HS.getFileSystemOpts());
  }

  if (isFramework())
    return DoFrameworkLookup(Filename, HS);

  assert(isHeaderMap() && "Unknown directory lookup");
  return getHeaderMap()->LookupFile(Filename, HS.getFileMgr(),
                                    HS.getFileSystemOpts());
}


/// DoFrameworkLookup - Do a lookup of the specified file in the current
/// DirectoryLookup, which is a framework directory.
const FileEntry *DirectoryLookup::DoFrameworkLookup(llvm::StringRef Filename,
                                                    HeaderSearch &HS) const {
  FileManager &FileMgr = HS.getFileMgr();
  const FileSystemOptions &FileSystemOpts = HS.getFileSystemOpts();

  // Framework names must have a '/' in the filename.
  size_t SlashPos = Filename.find('/');
  if (SlashPos == llvm::StringRef::npos) return 0;

  // Find out if this is the home for the specified framework, by checking
  // HeaderSearch.  Possible answer are yes/no and unknown.
  const DirectoryEntry *&FrameworkDirCache =
    HS.LookupFrameworkCache(Filename.substr(0, SlashPos));

  // If it is known and in some other directory, fail.
  if (FrameworkDirCache && FrameworkDirCache != getFrameworkDir())
    return 0;

  // Otherwise, construct the path to this framework dir.

  // FrameworkName = "/System/Library/Frameworks/"
  llvm::SmallString<1024> FrameworkName;
  FrameworkName += getFrameworkDir()->getName();
  if (FrameworkName.empty() || FrameworkName.back() != '/')
    FrameworkName.push_back('/');

  // FrameworkName = "/System/Library/Frameworks/Cocoa"
  FrameworkName.append(Filename.begin(), Filename.begin()+SlashPos);

  // FrameworkName = "/System/Library/Frameworks/Cocoa.framework/"
  FrameworkName += ".framework/";

  // If the cache entry is still unresolved, query to see if the cache entry is
  // still unresolved.  If so, check its existence now.
  if (FrameworkDirCache == 0) {
    HS.IncrementFrameworkLookupCount();

    // If the framework dir doesn't exist, we fail.
    // FIXME: It's probably more efficient to query this with FileMgr.getDir.
    if (!llvm::sys::Path(std::string(FrameworkName.begin(),
                                     FrameworkName.end())).exists())
      return 0;

    // Otherwise, if it does, remember that this is the right direntry for this
    // framework.
    FrameworkDirCache = getFrameworkDir();
  }

  // Check "/System/Library/Frameworks/Cocoa.framework/Headers/file.h"
  unsigned OrigSize = FrameworkName.size();

  FrameworkName += "Headers/";
  FrameworkName.append(Filename.begin()+SlashPos+1, Filename.end());
  if (const FileEntry *FE = FileMgr.getFile(FrameworkName.begin(),
                                            FrameworkName.end(),
                                            FileSystemOpts)) {
    return FE;
  }

  // Check "/System/Library/Frameworks/Cocoa.framework/PrivateHeaders/file.h"
  const char *Private = "Private";
  FrameworkName.insert(FrameworkName.begin()+OrigSize, Private,
                       Private+strlen(Private));
  return FileMgr.getFile(FrameworkName.begin(), FrameworkName.end(),
                         FileSystemOpts);
}


//===----------------------------------------------------------------------===//
// Header File Location.
//===----------------------------------------------------------------------===//


/// LookupFile - Given a "foo" or <foo> reference, look up the indicated file,
/// return null on failure.  isAngled indicates whether the file reference is
/// for system #include's or not (i.e. using <> instead of "").  CurFileEnt, if
/// non-null, indicates where the #including file is, in case a relative search
/// is needed.
const FileEntry *HeaderSearch::LookupFile(llvm::StringRef Filename,
                                          bool isAngled,
                                          const DirectoryLookup *FromDir,
                                          const DirectoryLookup *&CurDir,
                                          const FileEntry *CurFileEnt) {
  // If 'Filename' is absolute, check to see if it exists and no searching.
  if (llvm::sys::Path::isAbsolute(Filename.begin(), Filename.size())) {
    CurDir = 0;

    // If this was an #include_next "/absolute/file", fail.
    if (FromDir) return 0;

    // Otherwise, just return the file.
    return FileMgr.getFile(Filename, FileSystemOpts);
  }

  // Step #0, unless disabled, check to see if the file is in the #includer's
  // directory.  This has to be based on CurFileEnt, not CurDir, because
  // CurFileEnt could be a #include of a subdirectory (#include "foo/bar.h") and
  // a subsequent include of "baz.h" should resolve to "whatever/foo/baz.h".
  // This search is not done for <> headers.
  if (CurFileEnt && !isAngled<