lib/Lex/HeaderSearch.cpp - platform/external/clang - Gitiles

 //===--- 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;

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

   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)) {
     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(const char *FilenameStart,
                                              const char *FilenameEnd,
                                              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(FilenameStart, FilenameEnd);
     return HS.getFileMgr().getFile(TmpDir.begin(), TmpDir.end());
   }

   if (isFramework())
     return DoFrameworkLookup(FilenameStart, FilenameEnd, HS);

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


 /// DoFrameworkLookup - Do a lookup of the specified file in the current
 /// DirectoryLookup, which is a framework directory.
 const FileEntry *DirectoryLookup::DoFrameworkLookup(const char *FilenameStart,
                                                     const char *FilenameEnd,
                                                     HeaderSearch &HS) const {
   FileManager &FileMgr = HS.getFileMgr();

   // Framework names must have a '/' in the filename.
   const char *SlashPos = std::find(FilenameStart, FilenameEnd, '/');
   if (SlashPos == FilenameEnd) 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(FilenameStart, 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(FilenameStart, 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(SlashPos+1, FilenameEnd);
   if (const FileEntry *FE = FileMgr.getFile(FrameworkName.begin(),
                                             FrameworkName.end())) {
     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());
 }


 //===----------------------------------------------------------------------===//
 // 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(const char *FilenameStart,
                                           const char *FilenameEnd,
                                           bool isAngled,
                                           const DirectoryLookup *FromDir,
                                           const DirectoryLookup *&CurDir,
                                           const FileEntry *CurFileEnt) {
   // If 'Filename' is absolute, check to see if it exists and no searching.
   // FIXME: Portability.  This should be a sys::Path interface, this doesn't
   // handle things like C:\foo.txt right, nor win32 \\network\device\blah.
   if (FilenameStart[0] == '/') {
     CurDir = 0;

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

     // Otherwise, just return the file.
     return FileMgr.getFile(FilenameStart, FilenameEnd);
   }

   // 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 && !NoCurDirSearch) {
     llvm::SmallString<1024> TmpDir;
     // Concatenate the requested file onto the directory.
     // FIXME: Portability.  Filename concatenation should be in sys::Path.
     TmpDir += CurFileEnt->getDir()->getName();
     TmpDir.push_back('/');
     TmpDir.append(FilenameStart, FilenameEnd);
     if (const FileEntry *FE = FileMgr.getFile(TmpDir.begin(), TmpDir.end())) {
       // Leave CurDir unset.
       // This file is a system header or C++ unfriendly if the old file is.
       //
       // Note that the temporary 'DirInfo' is required here, as either call to
       // getFileInfo could resize the vector and we don't want to rely on order
       // of evaluation.
       unsigned DirInfo = getFileInfo(CurFileEnt).DirInfo;
       getFileInfo(FE).DirInfo = DirInfo;
       return FE;
     }
   }

   CurDir = 0;

   // If this is a system #include, ignore the user #include locs.
   unsigned i = isAngled ? SystemDirIdx : 0;

   // If this is a #include_next request, start searching after the directory the
   // file was found in.
   if (FromDir)
     i = FromDir-&SearchDirs[0];

   // Cache all of the lookups performed by this method.  Many headers are
   // multiply included, and the "pragma once" optimization prevents them from
   // being relex/pp'd, but they would still have to search through a
   // (potentially huge) series of SearchDirs to find it.
   std::pair<unsigned, unsigned> &CacheLookup =
     LookupFileCache.GetOrCreateValue(FilenameStart, FilenameEnd).getValue();

   // If the entry has been previously looked up, the first value will be
   // non-zero.  If the value is equal to i (the start point of our search), then
   // this is a matching hit.
   if (CacheLookup.first == i+1) {
     // Skip querying potentially lots of directories for this lookup.
     i = CacheLookup.second;
   } else {
     // Otherwise, this is the first query, or the previous query didn't match
     // our search start.  We will fill in our found location below, so prime the
     // start point value.
     CacheLookup.first = i+1;
   }

   // Check each directory in sequence to see if it contains this file.
   for (; i != SearchDirs.size(); ++i) {
     const FileEntry *FE =
       SearchDirs[i].LookupFile(FilenameStart, FilenameEnd, *this);
     if (!FE) continue;

     CurDir = &SearchDirs[i];

     // This file is a system header or C++ unfriendly if the dir is.
     getFileInfo(FE).DirInfo = CurDir->getDirCharacteristic();

     // Remember this location for the next lookup we do.
     CacheLookup.second = i;
     return FE;
   }

   // Otherwise, didn't find it. Remember we didn't find this.
   CacheLookup.second = SearchDirs.size();
   return 0;
 }

 /// LookupSubframeworkHeader - Look up a subframework for the specified
 /// #include file.  For example, if #include'ing <HIToolbox/HIToolbox.h> from
 /// within ".../Carbon.framework/Headers/Carbon.h", check to see if HIToolbox
 /// is a subframework within Carbon.framework.  If so, return the FileEntry
 /// for the designated file, otherwise return null.
 const FileEntry *HeaderSearch::
 LookupSubframeworkHeader(const char *FilenameStart,
                          const char *FilenameEnd,
                          const FileEntry *ContextFileEnt) {
   assert(ContextFileEnt && "No context file?");

   // Framework names must have a '/' in the filename.  Find it.
   const char *SlashPos = std::find(FilenameStart, FilenameEnd, '/');
   if (SlashPos == FilenameEnd) return 0;

   // Look up the base framework name of the ContextFileEnt.
   const char *ContextName = ContextFileEnt->getName();

   // If the context info wasn't a framework, couldn't be a subframework.
   const char *FrameworkPos = strstr(ContextName, ".framework/");
   if (FrameworkPos == 0)
     return 0;

   llvm::SmallString<1024> FrameworkName(ContextName,
                                         FrameworkPos+strlen(".framework/"));

   // Append Frameworks/HIToolbox.framework/
   FrameworkName += "Frameworks/";
   FrameworkName.append(FilenameStart, SlashPos);
   FrameworkName += ".framework/";

   llvm::StringMapEntry<const DirectoryEntry *> &CacheLookup =
     FrameworkMap.GetOrCreateValue(FilenameStart, SlashPos);

   // Some other location?
   if (CacheLookup.getValue() &&
       CacheLookup.getKeyLength() == FrameworkName.size() &&
       memcmp(CacheLookup.getKeyData(), &FrameworkName[0],
              CacheLookup.getKeyLength()) != 0)
     return 0;

   // Cache subframework.
   if (CacheLookup.getValue() == 0) {
     ++NumSubFrameworkLookups;

     // If the framework dir doesn't exist, we fail.
     const DirectoryEntry *Dir = FileMgr.getDirectory(FrameworkName.begin(),
                                                      FrameworkName.end());
     if (Dir == 0) return 0;

     // Otherwise, if it does, remember that this is the right direntry for this
     // framework.
     CacheLookup.setValue(Dir);
   }

   const FileEntry *FE = 0;

   // Check ".../Frameworks/HIToolbox.framework/Headers/HIToolbox.h"
   llvm::SmallString<1024> HeadersFilename(FrameworkName);
   HeadersFilename += "Headers/";
   HeadersFilename.append(SlashPos+1, FilenameEnd);
   if (!(FE = FileMgr.getFile(HeadersFilename.begin(),
                              HeadersFilename.end()))) {

     // Check ".../Frameworks/HIToolbox.framework/PrivateHeaders/HIToolbox.h"
     HeadersFilename = FrameworkName;
     HeadersFilename += "PrivateHeaders/";
     HeadersFilename.append(SlashPos+1, FilenameEnd);
     if (!(FE = FileMgr.getFile(HeadersFilename.begin(), HeadersFilename.end())))
       return 0;
   }

   // This file is a system header or C++ unfriendly if the old file is.
   //
   // Note that the temporary 'DirInfo' is required here, as either call to
   // getFileInfo could resize the vector and we don't want to rely on order
   // of evaluation.
   unsigned DirInfo = getFileInfo(ContextFileEnt).DirInfo;
   getFileInfo(FE).DirInfo = DirInfo;
   return FE;
 }

 //===----------------------------------------------------------------------===//
 // File Info Management.
 //===----------------------------------------------------------------------===//


 /// getFileInfo - Return the PerFileInfo structure for the specified
 /// FileEntry.
 HeaderSearch::PerFileInfo &HeaderSearch::getFileInfo(const FileEntry *FE) {
   if (FE->getUID() >= FileInfo.size())
     FileInfo.resize(FE->getUID()+1);
   return FileInfo[FE->getUID()];
 }

 /// ShouldEnterIncludeFile - Mark the specified file as a target of of a
 /// #include, #include_next, or #import directive.  Return false if #including
 /// the file will have no effect or true if we should include it.
 bool HeaderSearch::ShouldEnterIncludeFile(const FileEntry *File, bool isImport){
   ++NumIncluded; // Count # of attempted #includes.

   // Get information about this file.
   PerFileInfo &FileInfo = getFileInfo(File);

   // If this is a #import directive, check that we have not already imported
   // this header.
   if (isImport) {
     // If this has already been imported, don't import it again.
     FileInfo.isImport = true;

     // Has this already been #import'ed or #include'd?
     if (FileInfo.NumIncludes) return false;
   } else {
     // Otherwise, if this is a #include of a file that was previously #import'd
     // or if this is the second #include of a #pragma once file, ignore it.
     if (FileInfo.isImport)
       return false;
   }

   // Next, check to see if the file is wrapped with #ifndef guards.  If so, and
   // if the macro that guards it is defined, we know the #include has no effect.
   if (FileInfo.ControllingMacro &&
       FileInfo.ControllingMacro->hasMacroDefinition()) {
     ++NumMultiIncludeFileOptzn;
     return false;
   }

   // Increment the number of times this file has been included.
   ++FileInfo.NumIncludes;

   return true;
 }
	//===--- 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;

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

	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)) {
	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(const char FilenameStart,
	const char *FilenameEnd,
	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(FilenameStart, FilenameEnd);
	return HS.getFileMgr().getFile(TmpDir.begin(), TmpDir.end());
	}

	if (isFramework())
	return DoFrameworkLookup(FilenameStart, FilenameEnd, HS);

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


	/// DoFrameworkLookup - Do a lookup of the specified file in the current
	/// DirectoryLookup, which is a framework directory.
	const FileEntry DirectoryLookup::DoFrameworkLookup(const char FilenameStart,
	const char *FilenameEnd,
	HeaderSearch &HS) const {
	FileManager &FileMgr = HS.getFileMgr();

	// Framework names must have a '/' in the filename.
	const char *SlashPos = std::find(FilenameStart, FilenameEnd, '/');
	if (SlashPos == FilenameEnd) 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(FilenameStart, 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(FilenameStart, 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(SlashPos+1, FilenameEnd);
	if (const FileEntry *FE = FileMgr.getFile(FrameworkName.begin(),
	FrameworkName.end())) {
	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());
	}


	//===----------------------------------------------------------------------===//
	// 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(const char FilenameStart,
	const char *FilenameEnd,
	bool isAngled,
	const DirectoryLookup *FromDir,
	const DirectoryLookup *&CurDir,
	const FileEntry *CurFileEnt) {
	// If 'Filename' is absolute, check to see if it exists and no searching.
	// FIXME: Portability. This should be a sys::Path interface, this doesn't
	// handle things like C:\foo.txt right, nor win32 \\network\device\blah.
	if (FilenameStart[0] == '/') {
	CurDir = 0;

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

	// Otherwise, just return the file.
	return FileMgr.getFile(FilenameStart, FilenameEnd);
	}

	// 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 && !NoCurDirSearch) {
	llvm::SmallString<1024> TmpDir;
	// Concatenate the requested file onto the directory.
	// FIXME: Portability. Filename concatenation should be in sys::Path.
	TmpDir += CurFileEnt->getDir()->getName();
	TmpDir.push_back('/');
	TmpDir.append(FilenameStart, FilenameEnd);
	if (const FileEntry *FE = FileMgr.getFile(TmpDir.begin(), TmpDir.end())) {
	// Leave CurDir unset.
	// This file is a system header or C++ unfriendly if the old file is.
	//
	// Note that the temporary 'DirInfo' is required here, as either call to
	// getFileInfo could resize the vector and we don't want to rely on order
	// of evaluation.
	unsigned DirInfo = getFileInfo(CurFileEnt).DirInfo;
	getFileInfo(FE).DirInfo = DirInfo;
	return FE;
	}
	}

	CurDir = 0;

	// If this is a system #include, ignore the user #include locs.
	unsigned i = isAngled ? SystemDirIdx : 0;

	// If this is a #include_next request, start searching after the directory the
	// file was found in.
	if (FromDir)
	i = FromDir-&SearchDirs[0];

	// Cache all of the lookups performed by this method. Many headers are
	// multiply included, and the "pragma once" optimization prevents them from
	// being relex/pp'd, but they would still have to search through a
	// (potentially huge) series of SearchDirs to find it.
	std::pair<unsigned, unsigned> &CacheLookup =
	LookupFileCache.GetOrCreateValue(FilenameStart, FilenameEnd).getValue();

	// If the entry has been previously looked up, the first value will be
	// non-zero. If the value is equal to i (the start point of our search), then
	// this is a matching hit.
	if (CacheLookup.first == i+1) {
	// Skip querying potentially lots of directories for this lookup.
	i = CacheLookup.second;
	} else {
	// Otherwise, this is the first query, or the previous query didn't match
	// our search start. We will fill in our found location below, so prime the
	// start point value.
	CacheLookup.first = i+1;
	}

	// Check each directory in sequence to see if it contains this file.
	for (; i != SearchDirs.size(); ++i) {
	const FileEntry *FE =
	SearchDirs[i].LookupFile(FilenameStart, FilenameEnd, *this);
	if (!FE) continue;

	CurDir = &SearchDirs[i];

	// This file is a system header or C++ unfriendly if the dir is.
	getFileInfo(FE).DirInfo = CurDir->getDirCharacteristic();

	// Remember this location for the next lookup we do.
	CacheLookup.second = i;
	return FE;
	}

	// Otherwise, didn't find it. Remember we didn't find this.
	CacheLookup.second = SearchDirs.size();
	return 0;
	}

	/// LookupSubframeworkHeader - Look up a subframework for the specified
	/// #include file. For example, if #include'ing <HIToolbox/HIToolbox.h> from
	/// within ".../Carbon.framework/Headers/Carbon.h", check to see if HIToolbox
	/// is a subframework within Carbon.framework. If so, return the FileEntry
	/// for the designated file, otherwise return null.
	const FileEntry *HeaderSearch::
	LookupSubframeworkHeader(const char *FilenameStart,
	const char *FilenameEnd,
	const FileEntry *ContextFileEnt) {
	assert(ContextFileEnt && "No context file?");

	// Framework names must have a '/' in the filename. Find it.
	const char *SlashPos = std::find(FilenameStart, FilenameEnd, '/');
	if (SlashPos == FilenameEnd) return 0;

	// Look up the base framework name of the ContextFileEnt.
	const char *ContextName = ContextFileEnt->getName();

	// If the context info wasn't a framework, couldn't be a subframework.
	const char *FrameworkPos = strstr(ContextName, ".framework/");
	if (FrameworkPos == 0)
	return 0;

	llvm::SmallString<1024> FrameworkName(ContextName,
	FrameworkPos+strlen(".framework/"));

	// Append Frameworks/HIToolbox.framework/
	FrameworkName += "Frameworks/";
	FrameworkName.append(FilenameStart, SlashPos);
	FrameworkName += ".framework/";

	llvm::StringMapEntry<const DirectoryEntry *> &CacheLookup =
	FrameworkMap.GetOrCreateValue(FilenameStart, SlashPos);

	// Some other location?
	if (CacheLookup.getValue() &&
	CacheLookup.getKeyLength() == FrameworkName.size() &&
	memcmp(CacheLookup.getKeyData(), &FrameworkName[0],
	CacheLookup.getKeyLength()) != 0)
	return 0;

	// Cache subframework.
	if (CacheLookup.getValue() == 0) {
	++NumSubFrameworkLookups;

	// If the framework dir doesn't exist, we fail.
	const DirectoryEntry *Dir = FileMgr.getDirectory(FrameworkName.begin(),
	FrameworkName.end());
	if (Dir == 0) return 0;

	// Otherwise, if it does, remember that this is the right direntry for this
	// framework.
	CacheLookup.setValue(Dir);
	}

	const FileEntry *FE = 0;

	// Check ".../Frameworks/HIToolbox.framework/Headers/HIToolbox.h"
	llvm::SmallString<1024> HeadersFilename(FrameworkName);
	HeadersFilename += "Headers/";
	HeadersFilename.append(SlashPos+1, FilenameEnd);
	if (!(FE = FileMgr.getFile(HeadersFilename.begin(),
	HeadersFilename.end()))) {

	// Check ".../Frameworks/HIToolbox.framework/PrivateHeaders/HIToolbox.h"
	HeadersFilename = FrameworkName;
	HeadersFilename += "PrivateHeaders/";
	HeadersFilename.append(SlashPos+1, FilenameEnd);
	if (!(FE = FileMgr.getFile(HeadersFilename.begin(), HeadersFilename.end())))
	return 0;
	}

	// This file is a system header or C++ unfriendly if the old file is.
	//
	// Note that the temporary 'DirInfo' is required here, as either call to
	// getFileInfo could resize the vector and we don't want to rely on order
	// of evaluation.
	unsigned DirInfo = getFileInfo(ContextFileEnt).DirInfo;
	getFileInfo(FE).DirInfo = DirInfo;
	return FE;
	}

	//===----------------------------------------------------------------------===//
	// File Info Management.
	//===----------------------------------------------------------------------===//


	/// getFileInfo - Return the PerFileInfo structure for the specified
	/// FileEntry.
	HeaderSearch::PerFileInfo &HeaderSearch::getFileInfo(const FileEntry *FE) {
	if (FE->getUID() >= FileInfo.size())
	FileInfo.resize(FE->getUID()+1);
	return FileInfo[FE->getUID()];
	}

	/// ShouldEnterIncludeFile - Mark the specified file as a target of of a
	/// #include, #include_next, or #import directive. Return false if #including
	/// the file will have no effect or true if we should include it.
	bool HeaderSearch::ShouldEnterIncludeFile(const FileEntry *File, bool isImport){
	++NumIncluded; // Count # of attempted #includes.

	// Get information about this file.
	PerFileInfo &FileInfo = getFileInfo(File);

	// If this is a #import directive, check that we have not already imported
	// this header.
	if (isImport) {
	// If this has already been imported, don't import it again.
	FileInfo.isImport = true;

	// Has this already been #import'ed or #include'd?
	if (FileInfo.NumIncludes) return false;
	} else {
	// Otherwise, if this is a #include of a file that was previously #import'd
	// or if this is the second #include of a #pragma once file, ignore it.
	if (FileInfo.isImport)
	return false;
	}

	// Next, check to see if the file is wrapped with #ifndef guards. If so, and
	// if the macro that guards it is defined, we know the #include has no effect.
	if (FileInfo.ControllingMacro &&
	FileInfo.ControllingMacro->hasMacroDefinition()) {
	++NumMultiIncludeFileOptzn;
	return false;
	}

	// Increment the number of times this file has been included.
	++FileInfo.NumIncludes;

	return true;
	}