1 //===--- InitHeaderSearch.cpp - Initialize header search paths ------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements the InitHeaderSearch class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "clang/Basic/FileManager.h"
14 #include "clang/Basic/LangOptions.h"
15 #include "clang/Config/config.h" // C_INCLUDE_DIRS
16 #include "clang/Frontend/FrontendDiagnostic.h"
17 #include "clang/Frontend/Utils.h"
18 #include "clang/Lex/HeaderMap.h"
19 #include "clang/Lex/HeaderSearch.h"
20 #include "clang/Lex/HeaderSearchOptions.h"
21 #include "llvm/ADT/SmallPtrSet.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringExtras.h"
25 #include "llvm/ADT/Triple.h"
26 #include "llvm/ADT/Twine.h"
27 #include "llvm/Support/ErrorHandling.h"
28 #include "llvm/Support/Path.h"
29 #include "llvm/Support/raw_ostream.h"
30 
31 using namespace clang;
32 using namespace clang::frontend;
33 
34 namespace {
35 
36 /// InitHeaderSearch - This class makes it easier to set the search paths of
37 ///  a HeaderSearch object. InitHeaderSearch stores several search path lists
38 ///  internally, which can be sent to a HeaderSearch object in one swoop.
39 class InitHeaderSearch {
40   std::vector<std::pair<IncludeDirGroup, DirectoryLookup> > IncludePath;
41   typedef std::vector<std::pair<IncludeDirGroup,
42                       DirectoryLookup> >::const_iterator path_iterator;
43   std::vector<std::pair<std::string, bool> > SystemHeaderPrefixes;
44   HeaderSearch &Headers;
45   bool Verbose;
46   std::string IncludeSysroot;
47   bool HasSysroot;
48 
49 public:
50   InitHeaderSearch(HeaderSearch &HS, bool verbose, StringRef sysroot)
51       : Headers(HS), Verbose(verbose), IncludeSysroot(std::string(sysroot)),
52         HasSysroot(!(sysroot.empty() || sysroot == "/")) {}
53 
54   /// AddPath - Add the specified path to the specified group list, prefixing
55   /// the sysroot if used.
56   /// Returns true if the path exists, false if it was ignored.
57   bool AddPath(const Twine &Path, IncludeDirGroup Group, bool isFramework);
58 
59   /// AddUnmappedPath - Add the specified path to the specified group list,
60   /// without performing any sysroot remapping.
61   /// Returns true if the path exists, false if it was ignored.
62   bool AddUnmappedPath(const Twine &Path, IncludeDirGroup Group,
63                        bool isFramework);
64 
65   /// AddSystemHeaderPrefix - Add the specified prefix to the system header
66   /// prefix list.
67   void AddSystemHeaderPrefix(StringRef Prefix, bool IsSystemHeader) {
68     SystemHeaderPrefixes.emplace_back(std::string(Prefix), IsSystemHeader);
69   }
70 
71   /// AddGnuCPlusPlusIncludePaths - Add the necessary paths to support a gnu
72   ///  libstdc++.
73   /// Returns true if the \p Base path was found, false if it does not exist.
74   bool AddGnuCPlusPlusIncludePaths(StringRef Base, StringRef ArchDir,
75                                    StringRef Dir32, StringRef Dir64,
76                                    const llvm::Triple &triple);
77 
78   /// AddMinGWCPlusPlusIncludePaths - Add the necessary paths to support a MinGW
79   ///  libstdc++.
80   void AddMinGWCPlusPlusIncludePaths(StringRef Base,
81                                      StringRef Arch,
82                                      StringRef Version);
83 
84   // AddDefaultCIncludePaths - Add paths that should always be searched.
85   void AddDefaultCIncludePaths(const llvm::Triple &triple,
86                                const HeaderSearchOptions &HSOpts);
87 
88   // AddDefaultCPlusPlusIncludePaths -  Add paths that should be searched when
89   //  compiling c++.
90   void AddDefaultCPlusPlusIncludePaths(const LangOptions &LangOpts,
91                                        const llvm::Triple &triple,
92                                        const HeaderSearchOptions &HSOpts);
93 
94   /// AddDefaultSystemIncludePaths - Adds the default system include paths so
95   ///  that e.g. stdio.h is found.
96   void AddDefaultIncludePaths(const LangOptions &Lang,
97                               const llvm::Triple &triple,
98                               const HeaderSearchOptions &HSOpts);
99 
100   /// Realize - Merges all search path lists into one list and send it to
101   /// HeaderSearch.
102   void Realize(const LangOptions &Lang);
103 };
104 
105 }  // end anonymous namespace.
106 
107 static bool CanPrefixSysroot(StringRef Path) {
108 #if defined(_WIN32)
109   return !Path.empty() && llvm::sys::path::is_separator(Path[0]);
110 #else
111   return llvm::sys::path::is_absolute(Path);
112 #endif
113 }
114 
115 bool InitHeaderSearch::AddPath(const Twine &Path, IncludeDirGroup Group,
116                                bool isFramework) {
117   // Add the path with sysroot prepended, if desired and this is a system header
118   // group.
119   if (HasSysroot) {
120     SmallString<256> MappedPathStorage;
121     StringRef MappedPathStr = Path.toStringRef(MappedPathStorage);
122     if (CanPrefixSysroot(MappedPathStr)) {
123       return AddUnmappedPath(IncludeSysroot + Path, Group, isFramework);
124     }
125   }
126 
127   return AddUnmappedPath(Path, Group, isFramework);
128 }
129 
130 bool InitHeaderSearch::AddUnmappedPath(const Twine &Path, IncludeDirGroup Group,
131                                        bool isFramework) {
132   assert(!Path.isTriviallyEmpty() && "can't handle empty path here");
133 
134   FileManager &FM = Headers.getFileMgr();
135   SmallString<256> MappedPathStorage;
136   StringRef MappedPathStr = Path.toStringRef(MappedPathStorage);
137 
138   // If use system headers while cross-compiling, emit the warning.
139   if (HasSysroot && (MappedPathStr.startswith("/usr/include") ||
140                      MappedPathStr.startswith("/usr/local/include"))) {
141     Headers.getDiags().Report(diag::warn_poison_system_directories)
142         << MappedPathStr;
143   }
144 
145   // Compute the DirectoryLookup type.
146   SrcMgr::CharacteristicKind Type;
147   if (Group == Quoted || Group == Angled || Group == IndexHeaderMap) {
148     Type = SrcMgr::C_User;
149   } else if (Group == ExternCSystem) {
150     Type = SrcMgr::C_ExternCSystem;
151   } else {
152     Type = SrcMgr::C_System;
153   }
154 
155   // If the directory exists, add it.
156   if (auto DE = FM.getOptionalDirectoryRef(MappedPathStr)) {
157     IncludePath.push_back(
158       std::make_pair(Group, DirectoryLookup(*DE, Type, isFramework)));
159     return true;
160   }
161 
162   // Check to see if this is an apple-style headermap (which are not allowed to
163   // be frameworks).
164   if (!isFramework) {
165     if (auto FE = FM.getFile(MappedPathStr)) {
166       if (const HeaderMap *HM = Headers.CreateHeaderMap(*FE)) {
167         // It is a headermap, add it to the search path.
168         IncludePath.push_back(
169           std::make_pair(Group,
170                          DirectoryLookup(HM, Type, Group == IndexHeaderMap)));
171         return true;
172       }
173     }
174   }
175 
176   if (Verbose)
177     llvm::errs() << "ignoring nonexistent directory \""
178                  << MappedPathStr << "\"\n";
179   return false;
180 }
181 
182 bool InitHeaderSearch::AddGnuCPlusPlusIncludePaths(StringRef Base,
183                                                    StringRef ArchDir,
184                                                    StringRef Dir32,
185                                                    StringRef Dir64,
186                                                    const llvm::Triple &triple) {
187   // Add the base dir
188   bool IsBaseFound = AddPath(Base, CXXSystem, false);
189 
190   // Add the multilib dirs
191   llvm::Triple::ArchType arch = triple.getArch();
192   bool is64bit = arch == llvm::Triple::ppc64 || arch == llvm::Triple::x86_64;
193   if (is64bit)
194     AddPath(Base + "/" + ArchDir + "/" + Dir64, CXXSystem, false);
195   else
196     AddPath(Base + "/" + ArchDir + "/" + Dir32, CXXSystem, false);
197 
198   // Add the backward dir
199   AddPath(Base + "/backward", CXXSystem, false);
200   return IsBaseFound;
201 }
202 
203 void InitHeaderSearch::AddMinGWCPlusPlusIncludePaths(StringRef Base,
204                                                      StringRef Arch,
205                                                      StringRef Version) {
206   AddPath(Base + "/" + Arch + "/" + Version + "/include/c++",
207           CXXSystem, false);
208   AddPath(Base + "/" + Arch + "/" + Version + "/include/c++/" + Arch,
209           CXXSystem, false);
210   AddPath(Base + "/" + Arch + "/" + Version + "/include/c++/backward",
211           CXXSystem, false);
212 }
213 
214 void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
215                                             const HeaderSearchOptions &HSOpts) {
216   llvm::Triple::OSType os = triple.getOS();
217 
218   if (triple.isOSDarwin()) {
219     llvm_unreachable("Include management is handled in the driver.");
220   }
221 
222   if (HSOpts.UseStandardSystemIncludes) {
223     switch (os) {
224     case llvm::Triple::CloudABI:
225     case llvm::Triple::FreeBSD:
226     case llvm::Triple::NetBSD:
227     case llvm::Triple::OpenBSD:
228     case llvm::Triple::NaCl:
229     case llvm::Triple::PS4:
230     case llvm::Triple::ELFIAMCU:
231     case llvm::Triple::Fuchsia:
232       break;
233     case llvm::Triple::Win32:
234       if (triple.getEnvironment() != llvm::Triple::Cygnus)
235         break;
236       LLVM_FALLTHROUGH;
237     default:
238       // FIXME: temporary hack: hard-coded paths.
239       AddPath("/usr/local/include", System, false);
240       break;
241     }
242   }
243 
244   // Builtin includes use #include_next directives and should be positioned
245   // just prior C include dirs.
246   if (HSOpts.UseBuiltinIncludes) {
247     // Ignore the sys root, we *always* look for clang headers relative to
248     // supplied path.
249     SmallString<128> P = StringRef(HSOpts.ResourceDir);
250     llvm::sys::path::append(P, "include");
251     AddUnmappedPath(P, ExternCSystem, false);
252   }
253 
254   // All remaining additions are for system include directories, early exit if
255   // we aren't using them.
256   if (!HSOpts.UseStandardSystemIncludes)
257     return;
258 
259   // Add dirs specified via 'configure --with-c-include-dirs'.
260   StringRef CIncludeDirs(C_INCLUDE_DIRS);
261   if (CIncludeDirs != "") {
262     SmallVector<StringRef, 5> dirs;
263     CIncludeDirs.split(dirs, ":");
264     for (StringRef dir : dirs)
265       AddPath(dir, ExternCSystem, false);
266     return;
267   }
268 
269   switch (os) {
270   case llvm::Triple::Linux:
271   case llvm::Triple::Hurd:
272   case llvm::Triple::Solaris:
273     llvm_unreachable("Include management is handled in the driver.");
274 
275   case llvm::Triple::CloudABI: {
276     // <sysroot>/<triple>/include
277     SmallString<128> P = StringRef(HSOpts.ResourceDir);
278     llvm::sys::path::append(P, "../../..", triple.str(), "include");
279     AddPath(P, System, false);
280     break;
281   }
282 
283   case llvm::Triple::Haiku:
284     AddPath("/boot/system/non-packaged/develop/headers", System, false);
285     AddPath("/boot/system/develop/headers/os", System, false);
286     AddPath("/boot/system/develop/headers/os/app", System, false);
287     AddPath("/boot/system/develop/headers/os/arch", System, false);
288     AddPath("/boot/system/develop/headers/os/device", System, false);
289     AddPath("/boot/system/develop/headers/os/drivers", System, false);
290     AddPath("/boot/system/develop/headers/os/game", System, false);
291     AddPath("/boot/system/develop/headers/os/interface", System, false);
292     AddPath("/boot/system/develop/headers/os/kernel", System, false);
293     AddPath("/boot/system/develop/headers/os/locale", System, false);
294     AddPath("/boot/system/develop/headers/os/mail", System, false);
295     AddPath("/boot/system/develop/headers/os/media", System, false);
296     AddPath("/boot/system/develop/headers/os/midi", System, false);
297     AddPath("/boot/system/develop/headers/os/midi2", System, false);
298     AddPath("/boot/system/develop/headers/os/net", System, false);
299     AddPath("/boot/system/develop/headers/os/opengl", System, false);
300     AddPath("/boot/system/develop/headers/os/storage", System, false);
301     AddPath("/boot/system/develop/headers/os/support", System, false);
302     AddPath("/boot/system/develop/headers/os/translation", System, false);
303     AddPath("/boot/system/develop/headers/os/add-ons/graphics", System, false);
304     AddPath("/boot/system/develop/headers/os/add-ons/input_server", System, false);
305     AddPath("/boot/system/develop/headers/os/add-ons/mail_daemon", System, false);
306     AddPath("/boot/system/develop/headers/os/add-ons/registrar", System, false);
307     AddPath("/boot/system/develop/headers/os/add-ons/screen_saver", System, false);
308     AddPath("/boot/system/develop/headers/os/add-ons/tracker", System, false);
309     AddPath("/boot/system/develop/headers/os/be_apps/Deskbar", System, false);
310     AddPath("/boot/system/develop/headers/os/be_apps/NetPositive", System, false);
311     AddPath("/boot/system/develop/headers/os/be_apps/Tracker", System, false);
312     AddPath("/boot/system/develop/headers/3rdparty", System, false);
313     AddPath("/boot/system/develop/headers/bsd", System, false);
314     AddPath("/boot/system/develop/headers/glibc", System, false);
315     AddPath("/boot/system/develop/headers/posix", System, false);
316     AddPath("/boot/system/develop/headers",  System, false);
317     break;
318   case llvm::Triple::RTEMS:
319     break;
320   case llvm::Triple::Win32:
321     switch (triple.getEnvironment()) {
322     default: llvm_unreachable("Include management is handled in the driver.");
323     case llvm::Triple::Cygnus:
324       AddPath("/usr/include/w32api", System, false);
325       break;
326     case llvm::Triple::GNU:
327       break;
328     }
329     break;
330   default:
331     break;
332   }
333 
334   switch (os) {
335   case llvm::Triple::CloudABI:
336   case llvm::Triple::RTEMS:
337   case llvm::Triple::NaCl:
338   case llvm::Triple::ELFIAMCU:
339   case llvm::Triple::Fuchsia:
340     break;
341   case llvm::Triple::PS4: {
342     // <isysroot> gets prepended later in AddPath().
343     std::string BaseSDKPath = "";
344     if (!HasSysroot) {
345       const char *envValue = getenv("SCE_ORBIS_SDK_DIR");
346       if (envValue)
347         BaseSDKPath = envValue;
348       else {
349         // HSOpts.ResourceDir variable contains the location of Clang's
350         // resource files.
351         // Assuming that Clang is configured for PS4 without
352         // --with-clang-resource-dir option, the location of Clang's resource
353         // files is <SDK_DIR>/host_tools/lib/clang
354         SmallString<128> P = StringRef(HSOpts.ResourceDir);
355         llvm::sys::path::append(P, "../../..");
356         BaseSDKPath = std::string(P.str());
357       }
358     }
359     AddPath(BaseSDKPath + "/target/include", System, false);
360     if (triple.isPS4CPU())
361       AddPath(BaseSDKPath + "/target/include_common", System, false);
362     LLVM_FALLTHROUGH;
363   }
364   default:
365     AddPath("/usr/include", ExternCSystem, false);
366     break;
367   }
368 }
369 
370 void InitHeaderSearch::AddDefaultCPlusPlusIncludePaths(
371     const LangOptions &LangOpts, const llvm::Triple &triple,
372     const HeaderSearchOptions &HSOpts) {
373   llvm::Triple::OSType os = triple.getOS();
374   // FIXME: temporary hack: hard-coded paths.
375 
376   if (triple.isOSDarwin()) {
377     llvm_unreachable("Include management is handled in the driver.");
378   }
379 
380   switch (os) {
381   case llvm::Triple::Linux:
382   case llvm::Triple::Hurd:
383   case llvm::Triple::Solaris:
384   case llvm::Triple::AIX:
385     llvm_unreachable("Include management is handled in the driver.");
386     break;
387   case llvm::Triple::Win32:
388     switch (triple.getEnvironment()) {
389     default: llvm_unreachable("Include management is handled in the driver.");
390     case llvm::Triple::Cygnus:
391       // Cygwin-1.7
392       AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.7.3");
393       AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.5.3");
394       AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.3.4");
395       // g++-4 / Cygwin-1.5
396       AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.3.2");
397       break;
398     }
399     break;
400   case llvm::Triple::DragonFly:
401     AddPath("/usr/include/c++/5.0", CXXSystem, false);
402     break;
403   case llvm::Triple::Minix:
404     AddGnuCPlusPlusIncludePaths("/usr/gnu/include/c++/4.4.3",
405                                 "", "", "", triple);
406     break;
407   default:
408     break;
409   }
410 }
411 
412 void InitHeaderSearch::AddDefaultIncludePaths(const LangOptions &Lang,
413                                               const llvm::Triple &triple,
414                                             const HeaderSearchOptions &HSOpts) {
415   // NB: This code path is going away. All of the logic is moving into the
416   // driver which has the information necessary to do target-specific
417   // selections of default include paths. Each target which moves there will be
418   // exempted from this logic here until we can delete the entire pile of code.
419   switch (triple.getOS()) {
420   default:
421     break; // Everything else continues to use this routine's logic.
422 
423   case llvm::Triple::Emscripten:
424   case llvm::Triple::Linux:
425   case llvm::Triple::Hurd:
426   case llvm::Triple::Solaris:
427   case llvm::Triple::WASI:
428   case llvm::Triple::AIX:
429     return;
430 
431   case llvm::Triple::Win32:
432     if (triple.getEnvironment() != llvm::Triple::Cygnus ||
433         triple.isOSBinFormatMachO())
434       return;
435     break;
436 
437   case llvm::Triple::UnknownOS:
438     if (triple.isWasm())
439       return;
440     break;
441   }
442 
443   // All header search logic is handled in the Driver for Darwin.
444   if (triple.isOSDarwin()) {
445     if (HSOpts.UseStandardSystemIncludes) {
446       // Add the default framework include paths on Darwin.
447       AddPath("/System/Library/Frameworks", System, true);
448       AddPath("/Library/Frameworks", System, true);
449     }
450     return;
451   }
452 
453   if (Lang.CPlusPlus && !Lang.AsmPreprocessor &&
454       HSOpts.UseStandardCXXIncludes && HSOpts.UseStandardSystemIncludes) {
455     if (HSOpts.UseLibcxx) {
456       AddPath("/usr/include/c++/v1", CXXSystem, false);
457     } else {
458       AddDefaultCPlusPlusIncludePaths(Lang, triple, HSOpts);
459     }
460   }
461 
462   AddDefaultCIncludePaths(triple, HSOpts);
463 }
464 
465 /// RemoveDuplicates - If there are duplicate directory entries in the specified
466 /// search list, remove the later (dead) ones.  Returns the number of non-system
467 /// headers removed, which is used to update NumAngled.
468 static unsigned RemoveDuplicates(std::vector<DirectoryLookup> &SearchList,
469                                  unsigned First, bool Verbose) {
470   llvm::SmallPtrSet<const DirectoryEntry *, 8> SeenDirs;
471   llvm::SmallPtrSet<const DirectoryEntry *, 8> SeenFrameworkDirs;
472   llvm::SmallPtrSet<const HeaderMap *, 8> SeenHeaderMaps;
473   unsigned NonSystemRemoved = 0;
474   for (unsigned i = First; i != SearchList.size(); ++i) {
475     unsigned DirToRemove = i;
476 
477     const DirectoryLookup &CurEntry = SearchList[i];
478 
479     if (CurEntry.isNormalDir()) {
480       // If this isn't the first time we've seen this dir, remove it.
481       if (SeenDirs.insert(CurEntry.getDir()).second)
482         continue;
483     } else if (CurEntry.isFramework()) {
484       // If this isn't the first time we've seen this framework dir, remove it.
485       if (SeenFrameworkDirs.insert(CurEntry.getFrameworkDir()).second)
486         continue;
487     } else {
488       assert(CurEntry.isHeaderMap() && "Not a headermap or normal dir?");
489       // If this isn't the first time we've seen this headermap, remove it.
490       if (SeenHeaderMaps.insert(CurEntry.getHeaderMap()).second)
491         continue;
492     }
493 
494     // If we have a normal #include dir/framework/headermap that is shadowed
495     // later in the chain by a system include location, we actually want to
496     // ignore the user's request and drop the user dir... keeping the system
497     // dir.  This is weird, but required to emulate GCC's search path correctly.
498     //
499     // Since dupes of system dirs are rare, just rescan to find the original
500     // that we're nuking instead of using a DenseMap.
501     if (CurEntry.getDirCharacteristic() != SrcMgr::C_User) {
502       // Find the dir that this is the same of.
503       unsigned FirstDir;
504       for (FirstDir = First;; ++FirstDir) {
505         assert(FirstDir != i && "Didn't find dupe?");
506 
507         const DirectoryLookup &SearchEntry = SearchList[FirstDir];
508 
509         // If these are different lookup types, then they can't be the dupe.
510         if (SearchEntry.getLookupType() != CurEntry.getLookupType())
511           continue;
512 
513         bool isSame;
514         if (CurEntry.isNormalDir())
515           isSame = SearchEntry.getDir() == CurEntry.getDir();
516         else if (CurEntry.isFramework())
517           isSame = SearchEntry.getFrameworkDir() == CurEntry.getFrameworkDir();
518         else {
519           assert(CurEntry.isHeaderMap() && "Not a headermap or normal dir?");
520           isSame = SearchEntry.getHeaderMap() == CurEntry.getHeaderMap();
521         }
522 
523         if (isSame)
524           break;
525       }
526 
527       // If the first dir in the search path is a non-system dir, zap it
528       // instead of the system one.
529       if (SearchList[FirstDir].getDirCharacteristic() == SrcMgr::C_User)
530         DirToRemove = FirstDir;
531     }
532 
533     if (Verbose) {
534       llvm::errs() << "ignoring duplicate directory \""
535                    << CurEntry.getName() << "\"\n";
536       if (DirToRemove != i)
537         llvm::errs() << "  as it is a non-system directory that duplicates "
538                      << "a system directory\n";
539     }
540     if (DirToRemove != i)
541       ++NonSystemRemoved;
542 
543     // This is reached if the current entry is a duplicate.  Remove the
544     // DirToRemove (usually the current dir).
545     SearchList.erase(SearchList.begin()+DirToRemove);
546     --i;
547   }
548   return NonSystemRemoved;
549 }
550 
551 
552 void InitHeaderSearch::Realize(const LangOptions &Lang) {
553   // Concatenate ANGLE+SYSTEM+AFTER chains together into SearchList.
554   std::vector<DirectoryLookup> SearchList;
555   SearchList.reserve(IncludePath.size());
556 
557   // Quoted arguments go first.
558   for (auto &Include : IncludePath)
559     if (Include.first == Quoted)
560       SearchList.push_back(Include.second);
561 
562   // Deduplicate and remember index.
563   RemoveDuplicates(SearchList, 0, Verbose);
564   unsigned NumQuoted = SearchList.size();
565 
566   for (auto &Include : IncludePath)
567     if (Include.first == Angled || Include.first == IndexHeaderMap)
568       SearchList.push_back(Include.second);
569 
570   RemoveDuplicates(SearchList, NumQuoted, Verbose);
571   unsigned NumAngled = SearchList.size();
572 
573   for (auto &Include : IncludePath)
574     if (Include.first == System || Include.first == ExternCSystem ||
575         (!Lang.ObjC && !Lang.CPlusPlus && Include.first == CSystem) ||
576         (/*FIXME !Lang.ObjC && */ Lang.CPlusPlus &&
577          Include.first == CXXSystem) ||
578         (Lang.ObjC && !Lang.CPlusPlus && Include.first == ObjCSystem) ||
579         (Lang.ObjC && Lang.CPlusPlus && Include.first == ObjCXXSystem))
580       SearchList.push_back(Include.second);
581 
582   for (auto &Include : IncludePath)
583     if (Include.first == After)
584       SearchList.push_back(Include.second);
585 
586   // Remove duplicates across both the Angled and System directories.  GCC does
587   // this and failing to remove duplicates across these two groups breaks
588   // #include_next.
589   unsigned NonSystemRemoved = RemoveDuplicates(SearchList, NumQuoted, Verbose);
590   NumAngled -= NonSystemRemoved;
591 
592   bool DontSearchCurDir = false;  // TODO: set to true if -I- is set?
593   Headers.SetSearchPaths(SearchList, NumQuoted, NumAngled, DontSearchCurDir);
594 
595   Headers.SetSystemHeaderPrefixes(SystemHeaderPrefixes);
596 
597   // If verbose, print the list of directories that will be searched.
598   if (Verbose) {
599     llvm::errs() << "#include \"...\" search starts here:\n";
600     for (unsigned i = 0, e = SearchList.size(); i != e; ++i) {
601       if (i == NumQuoted)
602         llvm::errs() << "#include <...> search starts here:\n";
603       StringRef Name = SearchList[i].getName();
604       const char *Suffix;
605       if (SearchList[i].isNormalDir())
606         Suffix = "";
607       else if (SearchList[i].isFramework())
608         Suffix = " (framework directory)";
609       else {
610         assert(SearchList[i].isHeaderMap() && "Unknown DirectoryLookup");
611         Suffix = " (headermap)";
612       }
613       llvm::errs() << " " << Name << Suffix << "\n";
614     }
615     llvm::errs() << "End of search list.\n";
616   }
617 }
618 
619 void clang::ApplyHeaderSearchOptions(HeaderSearch &HS,
620                                      const HeaderSearchOptions &HSOpts,
621                                      const LangOptions &Lang,
622                                      const llvm::Triple &Triple) {
623   InitHeaderSearch Init(HS, HSOpts.Verbose, HSOpts.Sysroot);
624 
625   // Add the user defined entries.
626   for (unsigned i = 0, e = HSOpts.UserEntries.size(); i != e; ++i) {
627     const HeaderSearchOptions::Entry &E = HSOpts.UserEntries[i];
628     if (E.IgnoreSysRoot) {
629       Init.AddUnmappedPath(E.Path, E.Group, E.IsFramework);
630     } else {
631       Init.AddPath(E.Path, E.Group, E.IsFramework);
632     }
633   }
634 
635   Init.AddDefaultIncludePaths(Lang, Triple, HSOpts);
636 
637   for (unsigned i = 0, e = HSOpts.SystemHeaderPrefixes.size(); i != e; ++i)
638     Init.AddSystemHeaderPrefix(HSOpts.SystemHeaderPrefixes[i].Prefix,
639                                HSOpts.SystemHeaderPrefixes[i].IsSystemHeader);
640 
641   if (HSOpts.UseBuiltinIncludes) {
642     // Set up the builtin include directory in the module map.
643     SmallString<128> P = StringRef(HSOpts.ResourceDir);
644     llvm::sys::path::append(P, "include");
645     if (auto Dir = HS.getFileMgr().getDirectory(P))
646       HS.getModuleMap().setBuiltinIncludeDir(*Dir);
647   }
648 
649   Init.Realize(Lang);
650 }
651