1 //===--- InitHeaderSearch.cpp - Initialize header search paths ------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the InitHeaderSearch class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Frontend/Utils.h"
15 #include "clang/Basic/FileManager.h"
16 #include "clang/Basic/LangOptions.h"
17 #include "clang/Basic/Version.h"
18 #include "clang/Frontend/HeaderSearchOptions.h"
19 #include "clang/Lex/HeaderSearch.h"
20 #include "llvm/ADT/SmallString.h"
21 #include "llvm/ADT/SmallPtrSet.h"
22 #include "llvm/ADT/SmallVector.h"
23 #include "llvm/ADT/StringExtras.h"
24 #include "llvm/ADT/Triple.h"
25 #include "llvm/ADT/Twine.h"
26 #include "llvm/Support/raw_ostream.h"
27 #include "llvm/Support/ErrorHandling.h"
28 #include "llvm/Support/Path.h"
29 
30 #include "clang/Config/config.h" // C_INCLUDE_DIRS
31 
32 using namespace clang;
33 using namespace clang::frontend;
34 
35 namespace {
36 
37 /// InitHeaderSearch - This class makes it easier to set the search paths of
38 ///  a HeaderSearch object. InitHeaderSearch stores several search path lists
39 ///  internally, which can be sent to a HeaderSearch object in one swoop.
40 class InitHeaderSearch {
41   std::vector<std::pair<IncludeDirGroup, DirectoryLookup> > IncludePath;
42   typedef std::vector<std::pair<IncludeDirGroup,
43                       DirectoryLookup> >::const_iterator path_iterator;
44   HeaderSearch &Headers;
45   bool Verbose;
46   std::string IncludeSysroot;
47   bool IsNotEmptyOrRoot;
48 
49 public:
50 
51   InitHeaderSearch(HeaderSearch &HS, bool verbose, StringRef sysroot)
52     : Headers(HS), Verbose(verbose), IncludeSysroot(sysroot),
53       IsNotEmptyOrRoot(!(sysroot.empty() || sysroot == "/")) {
54   }
55 
56   /// AddPath - Add the specified path to the specified group list.
57   void AddPath(const Twine &Path, IncludeDirGroup Group,
58                bool isCXXAware, bool isUserSupplied,
59                bool isFramework, bool IgnoreSysRoot = false);
60 
61   /// AddGnuCPlusPlusIncludePaths - Add the necessary paths to support a gnu
62   ///  libstdc++.
63   void AddGnuCPlusPlusIncludePaths(StringRef Base,
64                                    StringRef ArchDir,
65                                    StringRef Dir32,
66                                    StringRef Dir64,
67                                    const llvm::Triple &triple);
68 
69   /// AddMinGWCPlusPlusIncludePaths - Add the necessary paths to support a MinGW
70   ///  libstdc++.
71   void AddMinGWCPlusPlusIncludePaths(StringRef Base,
72                                      StringRef Arch,
73                                      StringRef Version);
74 
75   /// AddMinGW64CXXPaths - Add the necessary paths to support
76   /// libstdc++ of x86_64-w64-mingw32 aka mingw-w64.
77   void AddMinGW64CXXPaths(StringRef Base,
78                           StringRef Version);
79 
80   // AddDefaultCIncludePaths - Add paths that should always be searched.
81   void AddDefaultCIncludePaths(const llvm::Triple &triple,
82                                const HeaderSearchOptions &HSOpts);
83 
84   // AddDefaultCPlusPlusIncludePaths -  Add paths that should be searched when
85   //  compiling c++.
86   void AddDefaultCPlusPlusIncludePaths(const llvm::Triple &triple,
87                                        const HeaderSearchOptions &HSOpts);
88 
89   /// AddDefaultSystemIncludePaths - Adds the default system include paths so
90   ///  that e.g. stdio.h is found.
91   void AddDefaultIncludePaths(const LangOptions &Lang,
92                               const llvm::Triple &triple,
93                               const HeaderSearchOptions &HSOpts);
94 
95   /// Realize - Merges all search path lists into one list and send it to
96   /// HeaderSearch.
97   void Realize(const LangOptions &Lang);
98 };
99 
100 }  // end anonymous namespace.
101 
102 void InitHeaderSearch::AddPath(const Twine &Path,
103                                IncludeDirGroup Group, bool isCXXAware,
104                                bool isUserSupplied, bool isFramework,
105                                bool IgnoreSysRoot) {
106   assert(!Path.isTriviallyEmpty() && "can't handle empty path here");
107   FileManager &FM = Headers.getFileMgr();
108 
109   // Compute the actual path, taking into consideration -isysroot.
110   SmallString<256> MappedPathStorage;
111   StringRef MappedPathStr = Path.toStringRef(MappedPathStorage);
112 
113   // Handle isysroot.
114   if ((Group == System || Group == CXXSystem) && !IgnoreSysRoot &&
115 #if defined(_WIN32)
116       !MappedPathStr.empty() &&
117       llvm::sys::path::is_separator(MappedPathStr[0]) &&
118 #else
119       llvm::sys::path::is_absolute(MappedPathStr) &&
120 #endif
121       IsNotEmptyOrRoot) {
122     MappedPathStorage.clear();
123     MappedPathStr =
124       (IncludeSysroot + Path).toStringRef(MappedPathStorage);
125   }
126 
127   // Compute the DirectoryLookup type.
128   SrcMgr::CharacteristicKind Type;
129   if (Group == Quoted || Group == Angled || Group == IndexHeaderMap)
130     Type = SrcMgr::C_User;
131   else if (isCXXAware)
132     Type = SrcMgr::C_System;
133   else
134     Type = SrcMgr::C_ExternCSystem;
135 
136 
137   // If the directory exists, add it.
138   if (const DirectoryEntry *DE = FM.getDirectory(MappedPathStr)) {
139     IncludePath.push_back(std::make_pair(Group, DirectoryLookup(DE, Type,
140                           isUserSupplied, isFramework)));
141     return;
142   }
143 
144   // Check to see if this is an apple-style headermap (which are not allowed to
145   // be frameworks).
146   if (!isFramework) {
147     if (const FileEntry *FE = FM.getFile(MappedPathStr)) {
148       if (const HeaderMap *HM = Headers.CreateHeaderMap(FE)) {
149         // It is a headermap, add it to the search path.
150         IncludePath.push_back(std::make_pair(Group, DirectoryLookup(HM, Type,
151                               isUserSupplied, Group == IndexHeaderMap)));
152         return;
153       }
154     }
155   }
156 
157   if (Verbose)
158     llvm::errs() << "ignoring nonexistent directory \""
159                  << MappedPathStr << "\"\n";
160 }
161 
162 void InitHeaderSearch::AddGnuCPlusPlusIncludePaths(StringRef Base,
163                                                    StringRef ArchDir,
164                                                    StringRef Dir32,
165                                                    StringRef Dir64,
166                                                    const llvm::Triple &triple) {
167   // Add the base dir
168   AddPath(Base, CXXSystem, true, false, false);
169 
170   // Add the multilib dirs
171   llvm::Triple::ArchType arch = triple.getArch();
172   bool is64bit = arch == llvm::Triple::ppc64 || arch == llvm::Triple::x86_64;
173   if (is64bit)
174     AddPath(Base + "/" + ArchDir + "/" + Dir64, CXXSystem, true, false, false);
175   else
176     AddPath(Base + "/" + ArchDir + "/" + Dir32, CXXSystem, true, false, false);
177 
178   // Add the backward dir
179   AddPath(Base + "/backward", CXXSystem, true, false, false);
180 }
181 
182 void InitHeaderSearch::AddMinGWCPlusPlusIncludePaths(StringRef Base,
183                                                      StringRef Arch,
184                                                      StringRef Version) {
185   AddPath(Base + "/" + Arch + "/" + Version + "/include/c++",
186           CXXSystem, true, false, false);
187   AddPath(Base + "/" + Arch + "/" + Version + "/include/c++/" + Arch,
188           CXXSystem, true, false, false);
189   AddPath(Base + "/" + Arch + "/" + Version + "/include/c++/backward",
190           CXXSystem, true, false, false);
191 }
192 
193 void InitHeaderSearch::AddMinGW64CXXPaths(StringRef Base,
194                                           StringRef Version) {
195   // Assumes Base is HeaderSearchOpts' ResourceDir
196   AddPath(Base + "/../../../include/c++/" + Version,
197           CXXSystem, true, false, false);
198   AddPath(Base + "/../../../include/c++/" + Version + "/x86_64-w64-mingw32",
199           CXXSystem, true, false, false);
200   AddPath(Base + "/../../../include/c++/" + Version + "/i686-w64-mingw32",
201           CXXSystem, true, false, false);
202   AddPath(Base + "/../../../include/c++/" + Version + "/backward",
203           CXXSystem, true, false, false);
204 }
205 
206 void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
207                                             const HeaderSearchOptions &HSOpts) {
208   llvm::Triple::OSType os = triple.getOS();
209 
210   if (HSOpts.UseStandardSystemIncludes) {
211     switch (os) {
212     case llvm::Triple::FreeBSD:
213     case llvm::Triple::NetBSD:
214       break;
215     default:
216       // FIXME: temporary hack: hard-coded paths.
217       AddPath("/usr/local/include", System, true, false, false);
218       break;
219     }
220   }
221 
222   // Builtin includes use #include_next directives and should be positioned
223   // just prior C include dirs.
224   if (HSOpts.UseBuiltinIncludes) {
225     // Ignore the sys root, we *always* look for clang headers relative to
226     // supplied path.
227     llvm::sys::Path P(HSOpts.ResourceDir);
228     P.appendComponent("include");
229     AddPath(P.str(), System, false, false, false, /*IgnoreSysRoot=*/ true);
230   }
231 
232   // All remaining additions are for system include directories, early exit if
233   // we aren't using them.
234   if (!HSOpts.UseStandardSystemIncludes)
235     return;
236 
237   // Add dirs specified via 'configure --with-c-include-dirs'.
238   StringRef CIncludeDirs(C_INCLUDE_DIRS);
239   if (CIncludeDirs != "") {
240     SmallVector<StringRef, 5> dirs;
241     CIncludeDirs.split(dirs, ":");
242     for (SmallVectorImpl<StringRef>::iterator i = dirs.begin();
243          i != dirs.end();
244          ++i)
245       AddPath(*i, System, false, false, false);
246     return;
247   }
248 
249   switch (os) {
250   case llvm::Triple::Linux:
251   case llvm::Triple::Win32:
252     llvm_unreachable("Include management is handled in the driver.");
253 
254   case llvm::Triple::Haiku:
255     AddPath("/boot/common/include", System, true, false, false);
256     AddPath("/boot/develop/headers/os", System, true, false, false);
257     AddPath("/boot/develop/headers/os/app", System, true, false, false);
258     AddPath("/boot/develop/headers/os/arch", System, true, false, false);
259     AddPath("/boot/develop/headers/os/device", System, true, false, false);
260     AddPath("/boot/develop/headers/os/drivers", System, true, false, false);
261     AddPath("/boot/develop/headers/os/game", System, true, false, false);
262     AddPath("/boot/develop/headers/os/interface", System, true, false, false);
263     AddPath("/boot/develop/headers/os/kernel", System, true, false, false);
264     AddPath("/boot/develop/headers/os/locale", System, true, false, false);
265     AddPath("/boot/develop/headers/os/mail", System, true, false, false);
266     AddPath("/boot/develop/headers/os/media", System, true, false, false);
267     AddPath("/boot/develop/headers/os/midi", System, true, false, false);
268     AddPath("/boot/develop/headers/os/midi2", System, true, false, false);
269     AddPath("/boot/develop/headers/os/net", System, true, false, false);
270     AddPath("/boot/develop/headers/os/storage", System, true, false, false);
271     AddPath("/boot/develop/headers/os/support", System, true, false, false);
272     AddPath("/boot/develop/headers/os/translation",
273       System, true, false, false);
274     AddPath("/boot/develop/headers/os/add-ons/graphics",
275       System, true, false, false);
276     AddPath("/boot/develop/headers/os/add-ons/input_server",
277       System, true, false, false);
278     AddPath("/boot/develop/headers/os/add-ons/screen_saver",
279       System, true, false, false);
280     AddPath("/boot/develop/headers/os/add-ons/tracker",
281       System, true, false, false);
282     AddPath("/boot/develop/headers/os/be_apps/Deskbar",
283       System, true, false, false);
284     AddPath("/boot/develop/headers/os/be_apps/NetPositive",
285       System, true, false, false);
286     AddPath("/boot/develop/headers/os/be_apps/Tracker",
287       System, true, false, false);
288     AddPath("/boot/develop/headers/cpp", System, true, false, false);
289     AddPath("/boot/develop/headers/cpp/i586-pc-haiku",
290       System, true, false, false);
291     AddPath("/boot/develop/headers/3rdparty", System, true, false, false);
292     AddPath("/boot/develop/headers/bsd", System, true, false, false);
293     AddPath("/boot/develop/headers/glibc", System, true, false, false);
294     AddPath("/boot/develop/headers/posix", System, true, false, false);
295     AddPath("/boot/develop/headers",  System, true, false, false);
296     break;
297   case llvm::Triple::RTEMS:
298     break;
299   case llvm::Triple::Cygwin:
300     AddPath("/usr/include/w32api", System, true, false, false);
301     break;
302   case llvm::Triple::MinGW32: {
303       // mingw-w64 crt include paths
304       llvm::sys::Path P(HSOpts.ResourceDir);
305       P.appendComponent("../../../i686-w64-mingw32/include"); // <sysroot>/i686-w64-mingw32/include
306       AddPath(P.str(), System, true, false, false);
307       P = llvm::sys::Path(HSOpts.ResourceDir);
308       P.appendComponent("../../../x86_64-w64-mingw32/include"); // <sysroot>/x86_64-w64-mingw32/include
309       AddPath(P.str(), System, true, false, false);
310       // mingw.org crt include paths
311       P = llvm::sys::Path(HSOpts.ResourceDir);
312       P.appendComponent("../../../include"); // <sysroot>/include
313       AddPath(P.str(), System, true, false, false);
314       AddPath("/mingw/include", System, true, false, false);
315       AddPath("c:/mingw/include", System, true, false, false);
316     }
317     break;
318   case llvm::Triple::FreeBSD:
319     AddPath("/usr/include/clang/" CLANG_VERSION_STRING,
320       System, false, false, false);
321     break;
322 
323   default:
324     break;
325   }
326 
327   if ( os != llvm::Triple::RTEMS )
328     AddPath("/usr/include", System, false, false, false);
329 }
330 
331 void InitHeaderSearch::
332 AddDefaultCPlusPlusIncludePaths(const llvm::Triple &triple, const HeaderSearchOptions &HSOpts) {
333   llvm::Triple::OSType os = triple.getOS();
334   // FIXME: temporary hack: hard-coded paths.
335 
336   if (triple.isOSDarwin()) {
337     switch (triple.getArch()) {
338     default: break;
339 
340     case llvm::Triple::ppc:
341     case llvm::Triple::ppc64:
342       AddGnuCPlusPlusIncludePaths("/usr/include/c++/4.2.1",
343                                   "powerpc-apple-darwin10", "", "ppc64",
344                                   triple);
345       AddGnuCPlusPlusIncludePaths("/usr/include/c++/4.0.0",
346                                   "powerpc-apple-darwin10", "", "ppc64",
347                                   triple);
348       break;
349 
350     case llvm::Triple::x86:
351     case llvm::Triple::x86_64:
352       AddGnuCPlusPlusIncludePaths("/usr/include/c++/4.2.1",
353                                   "i686-apple-darwin10", "", "x86_64", triple);
354       AddGnuCPlusPlusIncludePaths("/usr/include/c++/4.0.0",
355                                   "i686-apple-darwin8", "", "", triple);
356       break;
357 
358     case llvm::Triple::arm:
359     case llvm::Triple::thumb:
360       AddGnuCPlusPlusIncludePaths("/usr/include/c++/4.2.1",
361                                   "arm-apple-darwin10", "v7", "", triple);
362       AddGnuCPlusPlusIncludePaths("/usr/include/c++/4.2.1",
363                                   "arm-apple-darwin10", "v6", "", triple);
364       break;
365     }
366     return;
367   }
368 
369   switch (os) {
370   case llvm::Triple::Linux:
371   case llvm::Triple::Win32:
372     llvm_unreachable("Include management is handled in the driver.");
373 
374   case llvm::Triple::Cygwin:
375     // Cygwin-1.7
376     AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.5.3");
377     AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.3.4");
378     // g++-4 / Cygwin-1.5
379     AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.3.2");
380     break;
381   case llvm::Triple::MinGW32:
382     // mingw-w64 C++ include paths (i686-w64-mingw32 and x86_64-w64-mingw32)
383     AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.5.0");
384     AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.5.1");
385     AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.5.2");
386     AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.5.3");
387     AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.5.4");
388     AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.6.0");
389     AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.6.1");
390     AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.6.2");
391     AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.6.3");
392     AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.7.0");
393     // mingw.org C++ include paths
394     AddMinGWCPlusPlusIncludePaths("/mingw/lib/gcc", "mingw32", "4.5.2"); //MSYS
395     AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.6.2");
396     AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.6.1");
397     AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.5.2");
398     AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.5.0");
399     AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.4.0");
400     AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.3.0");
401     break;
402   case llvm::Triple::DragonFly:
403     AddPath("/usr/include/c++/4.1", CXXSystem, true, false, false);
404     break;
405   case llvm::Triple::FreeBSD:
406     // FreeBSD 8.0
407     // FreeBSD 7.3
408     AddGnuCPlusPlusIncludePaths("/usr/include/c++/4.2", "", "", "", triple);
409     AddGnuCPlusPlusIncludePaths("/usr/include/c++/4.2/backward",
410                                 "", "", "", triple);
411     break;
412   case llvm::Triple::NetBSD:
413     AddGnuCPlusPlusIncludePaths("/usr/include/g++", "", "", "", triple);
414     break;
415   case llvm::Triple::OpenBSD: {
416     std::string t = triple.getTriple();
417     if (t.substr(0, 6) == "x86_64")
418       t.replace(0, 6, "amd64");
419     AddGnuCPlusPlusIncludePaths("/usr/include/g++",
420                                 t, "", "", triple);
421     break;
422   }
423   case llvm::Triple::Minix:
424     AddGnuCPlusPlusIncludePaths("/usr/gnu/include/c++/4.4.3",
425                                 "", "", "", triple);
426     break;
427   case llvm::Triple::Solaris:
428     AddGnuCPlusPlusIncludePaths("/usr/gcc/4.5/include/c++/4.5.2/",
429                                 "i386-pc-solaris2.11", "", "", triple);
430     // Solaris - Fall though..
431   case llvm::Triple::AuroraUX:
432     // AuroraUX
433     AddGnuCPlusPlusIncludePaths("/opt/gcc4/include/c++/4.2.4",
434                                 "i386-pc-solaris2.11", "", "", triple);
435     break;
436   default:
437     break;
438   }
439 }
440 
441 void InitHeaderSearch::AddDefaultIncludePaths(const LangOptions &Lang,
442                                               const llvm::Triple &triple,
443                                             const HeaderSearchOptions &HSOpts) {
444   // NB: This code path is going away. All of the logic is moving into the
445   // driver which has the information necessary to do target-specific
446   // selections of default include paths. Each target which moves there will be
447   // exempted from this logic here until we can delete the entire pile of code.
448   switch (triple.getOS()) {
449   default:
450     break; // Everything else continues to use this routine's logic.
451 
452   case llvm::Triple::Linux:
453   case llvm::Triple::Win32:
454     return;
455   }
456 
457   if (Lang.CPlusPlus && HSOpts.UseStandardCXXIncludes &&
458       HSOpts.UseStandardSystemIncludes) {
459     if (HSOpts.UseLibcxx) {
460       if (triple.isOSDarwin()) {
461         // On Darwin, libc++ may be installed alongside the compiler in
462         // lib/c++/v1.
463         llvm::sys::Path P(HSOpts.ResourceDir);
464         if (!P.isEmpty()) {
465           P.eraseComponent();  // Remove version from foo/lib/clang/version
466           P.eraseComponent();  // Remove clang from foo/lib/clang
467 
468           // Get foo/lib/c++/v1
469           P.appendComponent("c++");
470           P.appendComponent("v1");
471           AddPath(P.str(), CXXSystem, true, false, false, true);
472         }
473       }
474       // On Solaris, include the support directory for things like xlocale and
475       // fudged system headers.
476       if (triple.getOS() == llvm::Triple::Solaris)
477         AddPath("/usr/include/c++/v1/support/solaris", CXXSystem, true, false,
478             false);
479 
480       AddPath("/usr/include/c++/v1", CXXSystem, true, false, false);
481     } else {
482       AddDefaultCPlusPlusIncludePaths(triple, HSOpts);
483     }
484   }
485 
486   AddDefaultCIncludePaths(triple, HSOpts);
487 
488   // Add the default framework include paths on Darwin.
489   if (HSOpts.UseStandardSystemIncludes) {
490     if (triple.isOSDarwin()) {
491       AddPath("/System/Library/Frameworks", System, true, false, true);
492       AddPath("/Library/Frameworks", System, true, false, true);
493     }
494   }
495 }
496 
497 /// RemoveDuplicates - If there are duplicate directory entries in the specified
498 /// search list, remove the later (dead) ones.  Returns the number of non-system
499 /// headers removed, which is used to update NumAngled.
500 static unsigned RemoveDuplicates(std::vector<DirectoryLookup> &SearchList,
501                                  unsigned First, bool Verbose) {
502   llvm::SmallPtrSet<const DirectoryEntry *, 8> SeenDirs;
503   llvm::SmallPtrSet<const DirectoryEntry *, 8> SeenFrameworkDirs;
504   llvm::SmallPtrSet<const HeaderMap *, 8> SeenHeaderMaps;
505   unsigned NonSystemRemoved = 0;
506   for (unsigned i = First; i != SearchList.size(); ++i) {
507     unsigned DirToRemove = i;
508 
509     const DirectoryLookup &CurEntry = SearchList[i];
510 
511     if (CurEntry.isNormalDir()) {
512       // If this isn't the first time we've seen this dir, remove it.
513       if (SeenDirs.insert(CurEntry.getDir()))
514         continue;
515     } else if (CurEntry.isFramework()) {
516       // If this isn't the first time we've seen this framework dir, remove it.
517       if (SeenFrameworkDirs.insert(CurEntry.getFrameworkDir()))
518         continue;
519     } else {
520       assert(CurEntry.isHeaderMap() && "Not a headermap or normal dir?");
521       // If this isn't the first time we've seen this headermap, remove it.
522       if (SeenHeaderMaps.insert(CurEntry.getHeaderMap()))
523         continue;
524     }
525 
526     // If we have a normal #include dir/framework/headermap that is shadowed
527     // later in the chain by a system include location, we actually want to
528     // ignore the user's request and drop the user dir... keeping the system
529     // dir.  This is weird, but required to emulate GCC's search path correctly.
530     //
531     // Since dupes of system dirs are rare, just rescan to find the original
532     // that we're nuking instead of using a DenseMap.
533     if (CurEntry.getDirCharacteristic() != SrcMgr::C_User) {
534       // Find the dir that this is the same of.
535       unsigned FirstDir;
536       for (FirstDir = 0; ; ++FirstDir) {
537         assert(FirstDir != i && "Didn't find dupe?");
538 
539         const DirectoryLookup &SearchEntry = SearchList[FirstDir];
540 
541         // If these are different lookup types, then they can't be the dupe.
542         if (SearchEntry.getLookupType() != CurEntry.getLookupType())
543           continue;
544 
545         bool isSame;
546         if (CurEntry.isNormalDir())
547           isSame = SearchEntry.getDir() == CurEntry.getDir();
548         else if (CurEntry.isFramework())
549           isSame = SearchEntry.getFrameworkDir() == CurEntry.getFrameworkDir();
550         else {
551           assert(CurEntry.isHeaderMap() && "Not a headermap or normal dir?");
552           isSame = SearchEntry.getHeaderMap() == CurEntry.getHeaderMap();
553         }
554 
555         if (isSame)
556           break;
557       }
558 
559       // If the first dir in the search path is a non-system dir, zap it
560       // instead of the system one.
561       if (SearchList[FirstDir].getDirCharacteristic() == SrcMgr::C_User)
562         DirToRemove = FirstDir;
563     }
564 
565     if (Verbose) {
566       llvm::errs() << "ignoring duplicate directory \""
567                    << CurEntry.getName() << "\"\n";
568       if (DirToRemove != i)
569         llvm::errs() << "  as it is a non-system directory that duplicates "
570                      << "a system directory\n";
571     }
572     if (DirToRemove != i)
573       ++NonSystemRemoved;
574 
575     // This is reached if the current entry is a duplicate.  Remove the
576     // DirToRemove (usually the current dir).
577     SearchList.erase(SearchList.begin()+DirToRemove);
578     --i;
579   }
580   return NonSystemRemoved;
581 }
582 
583 
584 void InitHeaderSearch::Realize(const LangOptions &Lang) {
585   // Concatenate ANGLE+SYSTEM+AFTER chains together into SearchList.
586   std::vector<DirectoryLookup> SearchList;
587   SearchList.reserve(IncludePath.size());
588 
589   // Quoted arguments go first.
590   for (path_iterator it = IncludePath.begin(), ie = IncludePath.end();
591        it != ie; ++it) {
592     if (it->first == Quoted)
593       SearchList.push_back(it->second);
594   }
595   // Deduplicate and remember index.
596   RemoveDuplicates(SearchList, 0, Verbose);
597   unsigned NumQuoted = SearchList.size();
598 
599   for (path_iterator it = IncludePath.begin(), ie = IncludePath.end();
600        it != ie; ++it) {
601     if (it->first == Angled || it->first == IndexHeaderMap)
602       SearchList.push_back(it->second);
603   }
604 
605   RemoveDuplicates(SearchList, NumQuoted, Verbose);
606   unsigned NumAngled = SearchList.size();
607 
608   for (path_iterator it = IncludePath.begin(), ie = IncludePath.end();
609        it != ie; ++it) {
610     if (it->first == System ||
611         (!Lang.ObjC1 && !Lang.CPlusPlus && it->first == CSystem)    ||
612         (/*FIXME !Lang.ObjC1 && */Lang.CPlusPlus  && it->first == CXXSystem)  ||
613         (Lang.ObjC1  && !Lang.CPlusPlus && it->first == ObjCSystem) ||
614         (Lang.ObjC1  && Lang.CPlusPlus  && it->first == ObjCXXSystem))
615       SearchList.push_back(it->second);
616   }
617 
618   for (path_iterator it = IncludePath.begin(), ie = IncludePath.end();
619        it != ie; ++it) {
620     if (it->first == After)
621       SearchList.push_back(it->second);
622   }
623 
624   // Remove duplicates across both the Angled and System directories.  GCC does
625   // this and failing to remove duplicates across these two groups breaks
626   // #include_next.
627   unsigned NonSystemRemoved = RemoveDuplicates(SearchList, NumQuoted, Verbose);
628   NumAngled -= NonSystemRemoved;
629 
630   bool DontSearchCurDir = false;  // TODO: set to true if -I- is set?
631   Headers.SetSearchPaths(SearchList, NumQuoted, NumAngled, DontSearchCurDir);
632 
633   // If verbose, print the list of directories that will be searched.
634   if (Verbose) {
635     llvm::errs() << "#include \"...\" search starts here:\n";
636     for (unsigned i = 0, e = SearchList.size(); i != e; ++i) {
637       if (i == NumQuoted)
638         llvm::errs() << "#include <...> search starts here:\n";
639       const char *Name = SearchList[i].getName();
640       const char *Suffix;
641       if (SearchList[i].isNormalDir())
642         Suffix = "";
643       else if (SearchList[i].isFramework())
644         Suffix = " (framework directory)";
645       else {
646         assert(SearchList[i].isHeaderMap() && "Unknown DirectoryLookup");
647         Suffix = " (headermap)";
648       }
649       llvm::errs() << " " << Name << Suffix << "\n";
650     }
651     llvm::errs() << "End of search list.\n";
652   }
653 }
654 
655 void clang::ApplyHeaderSearchOptions(HeaderSearch &HS,
656                                      const HeaderSearchOptions &HSOpts,
657                                      const LangOptions &Lang,
658                                      const llvm::Triple &Triple) {
659   InitHeaderSearch Init(HS, HSOpts.Verbose, HSOpts.Sysroot);
660 
661   // Add the user defined entries.
662   for (unsigned i = 0, e = HSOpts.UserEntries.size(); i != e; ++i) {
663     const HeaderSearchOptions::Entry &E = HSOpts.UserEntries[i];
664     Init.AddPath(E.Path, E.Group, !E.ImplicitExternC, E.IsUserSupplied,
665                  E.IsFramework, E.IgnoreSysRoot);
666   }
667 
668   Init.AddDefaultIncludePaths(Lang, Triple, HSOpts);
669 
670   if (HSOpts.UseBuiltinIncludes) {
671     // Set up the builtin include directory in the module map.
672     llvm::sys::Path P(HSOpts.ResourceDir);
673     P.appendComponent("include");
674     if (const DirectoryEntry *Dir = HS.getFileMgr().getDirectory(P.str()))
675       HS.getModuleMap().setBuiltinIncludeDir(Dir);
676   }
677 
678   Init.Realize(Lang);
679 }
680