[clang][lex] Remove -index-header-map (#114459)

This PR removes the `-index-header-map` functionality from Clang. AFAIK
this was only used internally at Apple and is now dead code. The main
motivation behind this change is to enable the removal of
`HeaderFileInfo::Framework` member and reducing the size of that data
structure.

rdar://84036149

Author: jansvoboda11

clang/include/clang/Driver/Options.td

@@ -4564,9 +4564,6 @@ def ibuiltininc : Flag<["-"], "ibuiltininc">, Group<clang_i_Group>,
   HelpText<"Enable builtin #include directories even when -nostdinc is used "
            "before or after -ibuiltininc. "
            "Using -nobuiltininc after the option disables it">;
-def index_header_map : Flag<["-"], "index-header-map">,
-  Visibility<[ClangOption, CC1Option]>,
-  HelpText<"Make the next included directory (-I or -F) an indexer header map">;
 def iapinotes_modules : JoinedOrSeparate<["-"], "iapinotes-modules">, Group<clang_i_Group>,
   Visibility<[ClangOption, CC1Option]>,
   HelpText<"Add directory to the API notes search path referenced by module name">, MetaVarName<"<directory>">;

clang/include/clang/Lex/DirectoryLookup.h

@@ -58,10 +58,6 @@ class DirectoryLookup {
   LLVM_PREFERRED_TYPE(LookupType_t)
   unsigned LookupType : 2;
 
-  /// Whether this is a header map used when building a framework.
-  LLVM_PREFERRED_TYPE(bool)
-  unsigned IsIndexHeaderMap : 1;
-
   /// Whether we've performed an exhaustive search for module maps
   /// within the subdirectories of this directory.
   LLVM_PREFERRED_TYPE(bool)
@@ -73,13 +69,12 @@ class DirectoryLookup {
                   bool isFramework)
       : u(Dir), DirCharacteristic(DT),
         LookupType(isFramework ? LT_Framework : LT_NormalDir),
-        IsIndexHeaderMap(false), SearchedAllModuleMaps(false) {}
+        SearchedAllModuleMaps(false) {}
 
   /// This ctor *does not take ownership* of 'Map'.
-  DirectoryLookup(const HeaderMap *Map, SrcMgr::CharacteristicKind DT,
-                  bool isIndexHeaderMap)
+  DirectoryLookup(const HeaderMap *Map, SrcMgr::CharacteristicKind DT)
       : u(Map), DirCharacteristic(DT), LookupType(LT_HeaderMap),
-        IsIndexHeaderMap(isIndexHeaderMap), SearchedAllModuleMaps(false) {}
+        SearchedAllModuleMaps(false) {}
 
   /// getLookupType - Return the kind of directory lookup that this is: either a
   /// normal directory, a framework path, or a HeaderMap.
@@ -146,11 +141,6 @@ class DirectoryLookup {
     return getDirCharacteristic() != SrcMgr::C_User;
   }
 
-  /// Whether this header map is building a framework or not.
-  bool isIndexHeaderMap() const {
-    return isHeaderMap() && IsIndexHeaderMap;
-  }
-
   /// LookupFile - Lookup the specified file in this search path, returning it
   /// if it exists or returning null if not.
   ///

clang/include/clang/Lex/HeaderSearch.h

@@ -108,16 +108,6 @@ struct HeaderFileInfo {
   LLVM_PREFERRED_TYPE(bool)
   unsigned Resolved : 1;
 
-  /// Whether this is a header inside a framework that is currently
-  /// being built.
-  ///
-  /// When a framework is being built, the headers have not yet been placed
-  /// into the appropriate framework subdirectories, and therefore are
-  /// provided via a header map. This bit indicates when this is one of
-  /// those framework headers.
-  LLVM_PREFERRED_TYPE(bool)
-  unsigned IndexHeaderMapHeader : 1;
-
   /// Whether this file has been looked up as a header.
   LLVM_PREFERRED_TYPE(bool)
   unsigned IsValid : 1;
@@ -140,7 +130,7 @@ struct HeaderFileInfo {
       : IsLocallyIncluded(false), isImport(false), isPragmaOnce(false),
         DirInfo(SrcMgr::C_User), External(false), isModuleHeader(false),
         isTextualModuleHeader(false), isCompilingModuleHeader(false),
-        Resolved(false), IndexHeaderMapHeader(false), IsValid(false) {}
+        Resolved(false), IsValid(false) {}
 
   /// Retrieve the controlling macro for this header file, if
   /// any.

clang/include/clang/Lex/HeaderSearchOptions.h

@@ -35,9 +35,6 @@ enum IncludeDirGroup {
   /// Paths for '\#include <>' added by '-I'.
   Angled,
 
-  /// Like Angled, but marks header maps used when building frameworks.
-  IndexHeaderMap,
-
   /// Like Angled, but marks system directories.
   System,
 

clang/lib/Driver/ToolChains/Clang.cpp

@@ -1185,8 +1185,7 @@ void Clang::AddPreprocessingOptions(Compilation &C, const JobAction &JA,
 
   Args.addAllArgs(CmdArgs,
                   {options::OPT_D, options::OPT_U, options::OPT_I_Group,
-                   options::OPT_F, options::OPT_index_header_map,
-                   options::OPT_embed_dir_EQ});
+                   options::OPT_F, options::OPT_embed_dir_EQ});
 
   // Add -Wp, and -Xpreprocessor if using the preprocessor.
 

clang/lib/Frontend/CompilerInvocation.cpp

@@ -3190,24 +3190,17 @@ static void GenerateHeaderSearchArgs(const HeaderSearchOptions &Opts,
   auto It = Opts.UserEntries.begin();
   auto End = Opts.UserEntries.end();
 
-  // Add -I..., -F..., and -index-header-map options in order.
-  for (; It < End && Matches(*It, {frontend::IndexHeaderMap, frontend::Angled},
-                             std::nullopt, true);
+  // Add -I... and -F... options in order.
+  for (; It < End && Matches(*It, {frontend::Angled}, std::nullopt, true);
        ++It) {
     OptSpecifier Opt = [It, Matches]() {
-      if (Matches(*It, frontend::IndexHeaderMap, true, true))
-        return OPT_F;
-      if (Matches(*It, frontend::IndexHeaderMap, false, true))
-        return OPT_I;
       if (Matches(*It, frontend::Angled, true, true))
         return OPT_F;
       if (Matches(*It, frontend::Angled, false, true))
         return OPT_I;
       llvm_unreachable("Unexpected HeaderSearchOptions::Entry.");
     }();
 
-    if (It->Group == frontend::IndexHeaderMap)
-      GenerateArg(Consumer, OPT_index_header_map);
     GenerateArg(Consumer, Opt, It->Path);
   };
 
@@ -3319,8 +3312,7 @@ static bool ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args,
         llvm::CachedHashString(MacroDef.split('=').first));
   }
 
-  // Add -I..., -F..., and -index-header-map options in order.
-  bool IsIndexHeaderMap = false;
+  // Add -I... and -F... options in order.
   bool IsSysrootSpecified =
       Args.hasArg(OPT__sysroot_EQ) || Args.hasArg(OPT_isysroot);
 
@@ -3339,20 +3331,10 @@ static bool ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args,
     return A->getValue();
   };
 
-  for (const auto *A : Args.filtered(OPT_I, OPT_F, OPT_index_header_map)) {
-    if (A->getOption().matches(OPT_index_header_map)) {
-      // -index-header-map applies to the next -I or -F.
-      IsIndexHeaderMap = true;
-      continue;
-    }
-
-    frontend::IncludeDirGroup Group =
-        IsIndexHeaderMap ? frontend::IndexHeaderMap : frontend::Angled;
-
+  for (const auto *A : Args.filtered(OPT_I, OPT_F)) {
     bool IsFramework = A->getOption().matches(OPT_F);
-    Opts.AddPath(PrefixHeaderPath(A, IsFramework), Group, IsFramework,
-                 /*IgnoreSysroot*/ true);
-    IsIndexHeaderMap = false;
+    Opts.AddPath(PrefixHeaderPath(A, IsFramework), frontend::Angled,
+                 IsFramework, /*IgnoreSysroot=*/true);
   }
 
   // Add -iprefix/-iwithprefix/-iwithprefixbefore options.

clang/lib/Lex/HeaderSearch.cpp

@@ -974,12 +974,10 @@ OptionalFileEntryRef HeaderSearch::LookupFile(
         const HeaderFileInfo *FromHFI = getExistingFileInfo(*Includer);
         assert(FromHFI && "includer without file info");
         unsigned DirInfo = FromHFI->DirInfo;
-        bool IndexHeaderMapHeader = FromHFI->IndexHeaderMapHeader;
         StringRef Framework = FromHFI->Framework;
 
         HeaderFileInfo &ToHFI = getFileInfo(*FE);
         ToHFI.DirInfo = DirInfo;
-        ToHFI.IndexHeaderMapHeader = IndexHeaderMapHeader;
         ToHFI.Framework = Framework;
 
         if (SearchPath) {
@@ -1125,14 +1123,7 @@ OptionalFileEntryRef HeaderSearch::LookupFile(
     // Set the `Framework` info if this file is in a header map with framework
     // style include spelling or found in a framework dir. The header map case
     // is possible when building frameworks which use header maps.
-    if (CurDir->isHeaderMap() && isAngled) {
-      size_t SlashPos = Filename.find('/');
-      if (SlashPos != StringRef::npos)
-        HFI.Framework =
-            getUniqueFrameworkName(StringRef(Filename.begin(), SlashPos));
-      if (CurDir->isIndexHeaderMap())
-        HFI.IndexHeaderMapHeader = 1;
-    } else if (CurDir->isFramework()) {
+    if ((CurDir->isHeaderMap() && isAngled) || CurDir->isFramework()) {
       size_t SlashPos = Filename.find('/');
       if (SlashPos != StringRef::npos)
         HFI.Framework =
@@ -1156,41 +1147,6 @@ OptionalFileEntryRef HeaderSearch::LookupFile(
     return File;
   }
 
-  // If we are including a file with a quoted include "foo.h" from inside
-  // a header in a framework that is currently being built, and we couldn't
-  // resolve "foo.h" any other way, change the include to <Foo/foo.h>, where
-  // "Foo" is the name of the framework in which the including header was found.
-  if (!Includers.empty() && Includers.front().first && !isAngled &&
-      !Filename.contains('/')) {
-    const HeaderFileInfo *IncludingHFI =
-        getExistingFileInfo(*Includers.front().first);
-    assert(IncludingHFI && "includer without file info");
-    if (IncludingHFI->IndexHeaderMapHeader) {
-      SmallString<128> ScratchFilename;
-      ScratchFilename += IncludingHFI->Framework;
-      ScratchFilename += '/';
-      ScratchFilename += Filename;
-
-      OptionalFileEntryRef File = LookupFile(
-          ScratchFilename, IncludeLoc, /*isAngled=*/true, FromDir, &CurDir,
-          Includers.front(), SearchPath, RelativePath, RequestingModule,
-          SuggestedModule, IsMapped, /*IsFrameworkFound=*/nullptr);
-
-      if (checkMSVCHeaderSearch(Diags, MSFE,
-                                File ? &File->getFileEntry() : nullptr,
-                                IncludeLoc)) {
-        if (SuggestedModule)
-          *SuggestedModule = MSSuggestedModule;
-        return MSFE;
-      }
-
-      cacheLookupSuccess(LookupFileCache[Filename],
-                         LookupFileCache[ScratchFilename].HitIt, IncludeLoc);
-      // FIXME: SuggestedModule.
-      return File;
-    }
-  }
-
   if (checkMSVCHeaderSearch(Diags, MSFE, nullptr, IncludeLoc)) {
     if (SuggestedModule)
       *SuggestedModule = MSSuggestedModule;
@@ -1358,7 +1314,6 @@ static void mergeHeaderFileInfo(HeaderFileInfo &HFI,
   HFI.DirInfo = OtherHFI.DirInfo;
   HFI.External = (!HFI.IsValid || HFI.External);
   HFI.IsValid = true;
-  HFI.IndexHeaderMapHeader = OtherHFI.IndexHeaderMapHeader;
 
   if (HFI.Framework.empty())
     HFI.Framework = OtherHFI.Framework;

clang/lib/Lex/InitHeaderSearch.cpp

@@ -149,7 +149,7 @@ bool InitHeaderSearch::AddUnmappedPath(const Twine &Path, IncludeDirGroup Group,
 
   // Compute the DirectoryLookup type.
   SrcMgr::CharacteristicKind Type;
-  if (Group == Quoted || Group == Angled || Group == IndexHeaderMap) {
+  if (Group == Quoted || Group == Angled) {
     Type = SrcMgr::C_User;
   } else if (Group == ExternCSystem) {
     Type = SrcMgr::C_ExternCSystem;
@@ -170,9 +170,8 @@ bool InitHeaderSearch::AddUnmappedPath(const Twine &Path, IncludeDirGroup Group,
     if (auto FE = FM.getOptionalFileRef(MappedPathStr)) {
       if (const HeaderMap *HM = Headers.CreateHeaderMap(*FE)) {
         // It is a headermap, add it to the search path.
-        IncludePath.emplace_back(
-            Group, DirectoryLookup(HM, Type, Group == IndexHeaderMap),
-            UserEntryIdx);
+        IncludePath.emplace_back(Group, DirectoryLookup(HM, Type),
+                                 UserEntryIdx);
         return true;
       }
     }
@@ -488,7 +487,7 @@ void InitHeaderSearch::Realize(const LangOptions &Lang) {
   unsigned NumQuoted = SearchList.size();
 
   for (auto &Include : IncludePath)
-    if (Include.Group == Angled || Include.Group == IndexHeaderMap)
+    if (Include.Group == Angled)
       SearchList.push_back(Include);
 
   RemoveDuplicates(SearchList, NumQuoted, Verbose);

clang/lib/Serialization/ASTReader.cpp

@@ -2120,7 +2120,6 @@ HeaderFileInfoTrait::ReadData(internal_key_ref key, const unsigned char *d,
   HFI.isImport |= (Flags >> 5) & 0x01;
   HFI.isPragmaOnce |= (Flags >> 4) & 0x01;
   HFI.DirInfo = (Flags >> 1) & 0x07;
-  HFI.IndexHeaderMapHeader = Flags & 0x01;
   HFI.LazyControllingMacro = Reader.getGlobalIdentifierID(
       M, endian::readNext<IdentifierID, llvm::endianness::little>(d));
   if (unsigned FrameworkOffset =

clang/lib/Serialization/ASTWriter.cpp

@@ -2036,8 +2036,7 @@ namespace {
                           | (Data.HFI.isImport << 5)
                           | (Writer.isWritingStdCXXNamedModules() ? 0 :
                              Data.HFI.isPragmaOnce << 4)
-                          | (Data.HFI.DirInfo << 1)
-                          | Data.HFI.IndexHeaderMapHeader;
+                          | (Data.HFI.DirInfo << 1);
       LE.write<uint8_t>(Flags);
 
       if (Data.HFI.LazyControllingMacro.isID())