Check in LLVM r95781.
diff --git a/lib/Basic/IdentifierTable.cpp b/lib/Basic/IdentifierTable.cpp
new file mode 100644
index 0000000..16a61b7
--- /dev/null
+++ b/lib/Basic/IdentifierTable.cpp
@@ -0,0 +1,399 @@
+//===--- IdentifierTable.cpp - Hash table for identifier lookup -----------===//
+//
+//                     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 IdentifierInfo, IdentifierVisitor, and
+// IdentifierTable interfaces.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/IdentifierTable.h"
+#include "clang/Basic/LangOptions.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cstdio>
+
+using namespace clang;
+
+//===----------------------------------------------------------------------===//
+// IdentifierInfo Implementation
+//===----------------------------------------------------------------------===//
+
+IdentifierInfo::IdentifierInfo() {
+  TokenID = tok::identifier;
+  ObjCOrBuiltinID = 0;
+  HasMacro = false;
+  IsExtension = false;
+  IsPoisoned = false;
+  IsCPPOperatorKeyword = false;
+  NeedsHandleIdentifier = false;
+  FETokenInfo = 0;
+  Entry = 0;
+}
+
+//===----------------------------------------------------------------------===//
+// IdentifierTable Implementation
+//===----------------------------------------------------------------------===//
+
+IdentifierInfoLookup::~IdentifierInfoLookup() {}
+
+ExternalIdentifierLookup::~ExternalIdentifierLookup() {}
+
+IdentifierTable::IdentifierTable(const LangOptions &LangOpts,
+                                 IdentifierInfoLookup* externalLookup)
+  : HashTable(8192), // Start with space for 8K identifiers.
+    ExternalLookup(externalLookup) {
+
+  // Populate the identifier table with info about keywords for the current
+  // language.
+  AddKeywords(LangOpts);
+}
+
+//===----------------------------------------------------------------------===//
+// Language Keyword Implementation
+//===----------------------------------------------------------------------===//
+
+// Constants for TokenKinds.def
+namespace {
+  enum {
+    KEYALL = 1,
+    KEYC99 = 2,
+    KEYCXX = 4,
+    KEYCXX0X = 8,
+    KEYGNU = 16,
+    KEYMS = 32,
+    BOOLSUPPORT = 64,
+    KEYALTIVEC = 128
+  };
+}
+
+/// AddKeyword - This method is used to associate a token ID with specific
+/// identifiers because they are language keywords.  This causes the lexer to
+/// automatically map matching identifiers to specialized token codes.
+///
+/// The C90/C99/CPP/CPP0x flags are set to 0 if the token should be
+/// enabled in the specified langauge, set to 1 if it is an extension
+/// in the specified language, and set to 2 if disabled in the
+/// specified language.
+static void AddKeyword(const char *Keyword, unsigned KWLen,
+                       tok::TokenKind TokenCode, unsigned Flags,
+                       const LangOptions &LangOpts, IdentifierTable &Table) {
+  unsigned AddResult = 0;
+  if (Flags & KEYALL) AddResult = 2;
+  else if (LangOpts.CPlusPlus && (Flags & KEYCXX)) AddResult = 2;
+  else if (LangOpts.CPlusPlus0x && (Flags & KEYCXX0X)) AddResult = 2;
+  else if (LangOpts.C99 && (Flags & KEYC99)) AddResult = 2;
+  else if (LangOpts.GNUMode && (Flags & KEYGNU)) AddResult = 1;
+  else if (LangOpts.Microsoft && (Flags & KEYMS)) AddResult = 1;
+  else if (LangOpts.Bool && (Flags & BOOLSUPPORT)) AddResult = 2;
+  else if (LangOpts.AltiVec && (Flags & KEYALTIVEC)) AddResult = 2;
+
+  // Don't add this keyword if disabled in this language.
+  if (AddResult == 0) return;
+
+  IdentifierInfo &Info = Table.get(Keyword, Keyword+KWLen);
+  Info.setTokenID(TokenCode);
+  Info.setIsExtensionToken(AddResult == 1);
+}
+
+/// AddCXXOperatorKeyword - Register a C++ operator keyword alternative
+/// representations.
+static void AddCXXOperatorKeyword(const char *Keyword, unsigned KWLen,
+                                  tok::TokenKind TokenCode,
+                                  IdentifierTable &Table) {
+  IdentifierInfo &Info = Table.get(Keyword, Keyword + KWLen);
+  Info.setTokenID(TokenCode);
+  Info.setIsCPlusPlusOperatorKeyword();
+}
+
+/// AddObjCKeyword - Register an Objective-C @keyword like "class" "selector" or
+/// "property".
+static void AddObjCKeyword(tok::ObjCKeywordKind ObjCID,
+                           const char *Name, unsigned NameLen,
+                           IdentifierTable &Table) {
+  Table.get(Name, Name+NameLen).setObjCKeywordID(ObjCID);
+}
+
+/// AddKeywords - Add all keywords to the symbol table.
+///
+void IdentifierTable::AddKeywords(const LangOptions &LangOpts) {
+  // Add keywords and tokens for the current language.
+#define KEYWORD(NAME, FLAGS) \
+  AddKeyword(#NAME, strlen(#NAME), tok::kw_ ## NAME,  \
+             FLAGS, LangOpts, *this);
+#define ALIAS(NAME, TOK, FLAGS) \
+  AddKeyword(NAME, strlen(NAME), tok::kw_ ## TOK,  \
+             FLAGS, LangOpts, *this);
+#define CXX_KEYWORD_OPERATOR(NAME, ALIAS) \
+  if (LangOpts.CXXOperatorNames)          \
+    AddCXXOperatorKeyword(#NAME, strlen(#NAME), tok::ALIAS, *this);
+#define OBJC1_AT_KEYWORD(NAME) \
+  if (LangOpts.ObjC1)          \
+    AddObjCKeyword(tok::objc_##NAME, #NAME, strlen(#NAME), *this);
+#define OBJC2_AT_KEYWORD(NAME) \
+  if (LangOpts.ObjC2)          \
+    AddObjCKeyword(tok::objc_##NAME, #NAME, strlen(#NAME), *this);
+#include "clang/Basic/TokenKinds.def"
+}
+
+tok::PPKeywordKind IdentifierInfo::getPPKeywordID() const {
+  // We use a perfect hash function here involving the length of the keyword,
+  // the first and third character.  For preprocessor ID's there are no
+  // collisions (if there were, the switch below would complain about duplicate
+  // case values).  Note that this depends on 'if' being null terminated.
+
+#define HASH(LEN, FIRST, THIRD) \
+  (LEN << 5) + (((FIRST-'a') + (THIRD-'a')) & 31)
+#define CASE(LEN, FIRST, THIRD, NAME) \
+  case HASH(LEN, FIRST, THIRD): \
+    return memcmp(Name, #NAME, LEN) ? tok::pp_not_keyword : tok::pp_ ## NAME
+
+  unsigned Len = getLength();
+  if (Len < 2) return tok::pp_not_keyword;
+  const char *Name = getNameStart();
+  switch (HASH(Len, Name[0], Name[2])) {
+  default: return tok::pp_not_keyword;
+  CASE( 2, 'i', '\0', if);
+  CASE( 4, 'e', 'i', elif);
+  CASE( 4, 'e', 's', else);
+  CASE( 4, 'l', 'n', line);
+  CASE( 4, 's', 'c', sccs);
+  CASE( 5, 'e', 'd', endif);
+  CASE( 5, 'e', 'r', error);
+  CASE( 5, 'i', 'e', ident);
+  CASE( 5, 'i', 'd', ifdef);
+  CASE( 5, 'u', 'd', undef);
+
+  CASE( 6, 'a', 's', assert);
+  CASE( 6, 'd', 'f', define);
+  CASE( 6, 'i', 'n', ifndef);
+  CASE( 6, 'i', 'p', import);
+  CASE( 6, 'p', 'a', pragma);
+
+  CASE( 7, 'd', 'f', defined);
+  CASE( 7, 'i', 'c', include);
+  CASE( 7, 'w', 'r', warning);
+
+  CASE( 8, 'u', 'a', unassert);
+  CASE(12, 'i', 'c', include_next);
+
+  CASE(16, '_', 'i', __include_macros);
+#undef CASE
+#undef HASH
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// Stats Implementation
+//===----------------------------------------------------------------------===//
+
+/// PrintStats - Print statistics about how well the identifier table is doing
+/// at hashing identifiers.
+void IdentifierTable::PrintStats() const {
+  unsigned NumBuckets = HashTable.getNumBuckets();
+  unsigned NumIdentifiers = HashTable.getNumItems();
+  unsigned NumEmptyBuckets = NumBuckets-NumIdentifiers;
+  unsigned AverageIdentifierSize = 0;
+  unsigned MaxIdentifierLength = 0;
+
+  // TODO: Figure out maximum times an identifier had to probe for -stats.
+  for (llvm::StringMap<IdentifierInfo*, llvm::BumpPtrAllocator>::const_iterator
+       I = HashTable.begin(), E = HashTable.end(); I != E; ++I) {
+    unsigned IdLen = I->getKeyLength();
+    AverageIdentifierSize += IdLen;
+    if (MaxIdentifierLength < IdLen)
+      MaxIdentifierLength = IdLen;
+  }
+
+  fprintf(stderr, "\n*** Identifier Table Stats:\n");
+  fprintf(stderr, "# Identifiers:   %d\n", NumIdentifiers);
+  fprintf(stderr, "# Empty Buckets: %d\n", NumEmptyBuckets);
+  fprintf(stderr, "Hash density (#identifiers per bucket): %f\n",
+          NumIdentifiers/(double)NumBuckets);
+  fprintf(stderr, "Ave identifier length: %f\n",
+          (AverageIdentifierSize/(double)NumIdentifiers));
+  fprintf(stderr, "Max identifier length: %d\n", MaxIdentifierLength);
+
+  // Compute statistics about the memory allocated for identifiers.
+  HashTable.getAllocator().PrintStats();
+}
+
+//===----------------------------------------------------------------------===//
+// SelectorTable Implementation
+//===----------------------------------------------------------------------===//
+
+unsigned llvm::DenseMapInfo<clang::Selector>::getHashValue(clang::Selector S) {
+  return DenseMapInfo<void*>::getHashValue(S.getAsOpaquePtr());
+}
+
+namespace clang {
+/// MultiKeywordSelector - One of these variable length records is kept for each
+/// selector containing more than one keyword. We use a folding set
+/// to unique aggregate names (keyword selectors in ObjC parlance). Access to
+/// this class is provided strictly through Selector.
+class MultiKeywordSelector
+  : public DeclarationNameExtra, public llvm::FoldingSetNode {
+  MultiKeywordSelector(unsigned nKeys) {
+    ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
+  }
+public:
+  // Constructor for keyword selectors.
+  MultiKeywordSelector(unsigned nKeys, IdentifierInfo **IIV) {
+    assert((nKeys > 1) && "not a multi-keyword selector");
+    ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
+
+    // Fill in the trailing keyword array.
+    IdentifierInfo **KeyInfo = reinterpret_cast<IdentifierInfo **>(this+1);
+    for (unsigned i = 0; i != nKeys; ++i)
+      KeyInfo[i] = IIV[i];
+  }
+
+  // getName - Derive the full selector name and return it.
+  std::string getName() const;
+
+  unsigned getNumArgs() const { return ExtraKindOrNumArgs - NUM_EXTRA_KINDS; }
+
+  typedef IdentifierInfo *const *keyword_iterator;
+  keyword_iterator keyword_begin() const {
+    return reinterpret_cast<keyword_iterator>(this+1);
+  }
+  keyword_iterator keyword_end() const {
+    return keyword_begin()+getNumArgs();
+  }
+  IdentifierInfo *getIdentifierInfoForSlot(unsigned i) const {
+    assert(i < getNumArgs() && "getIdentifierInfoForSlot(): illegal index");
+    return keyword_begin()[i];
+  }
+  static void Profile(llvm::FoldingSetNodeID &ID,
+                      keyword_iterator ArgTys, unsigned NumArgs) {
+    ID.AddInteger(NumArgs);
+    for (unsigned i = 0; i != NumArgs; ++i)
+      ID.AddPointer(ArgTys[i]);
+  }
+  void Profile(llvm::FoldingSetNodeID &ID) {
+    Profile(ID, keyword_begin(), getNumArgs());
+  }
+};
+} // end namespace clang.
+
+unsigned Selector::getNumArgs() const {
+  unsigned IIF = getIdentifierInfoFlag();
+  if (IIF == ZeroArg)
+    return 0;
+  if (IIF == OneArg)
+    return 1;
+  // We point to a MultiKeywordSelector (pointer doesn't contain any flags).
+  MultiKeywordSelector *SI = reinterpret_cast<MultiKeywordSelector *>(InfoPtr);
+  return SI->getNumArgs();
+}
+
+IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
+  if (getIdentifierInfoFlag()) {
+    assert(argIndex == 0 && "illegal keyword index");
+    return getAsIdentifierInfo();
+  }
+  // We point to a MultiKeywordSelector (pointer doesn't contain any flags).
+  MultiKeywordSelector *SI = reinterpret_cast<MultiKeywordSelector *>(InfoPtr);
+  return SI->getIdentifierInfoForSlot(argIndex);
+}
+
+std::string MultiKeywordSelector::getName() const {
+  llvm::SmallString<256> Str;
+  llvm::raw_svector_ostream OS(Str);
+  for (keyword_iterator I = keyword_begin(), E = keyword_end(); I != E; ++I) {
+    if (*I)
+      OS << (*I)->getName();
+    OS << ':';
+  }
+
+  return OS.str();
+}
+
+std::string Selector::getAsString() const {
+  if (InfoPtr == 0)
+    return "<null selector>";
+
+  if (InfoPtr & ArgFlags) {
+    IdentifierInfo *II = getAsIdentifierInfo();
+
+    // If the number of arguments is 0 then II is guaranteed to not be null.
+    if (getNumArgs() == 0)
+      return II->getName();
+
+    if (!II)
+      return ":";
+
+    return II->getName().str() + ":";
+  }
+
+  // We have a multiple keyword selector (no embedded flags).
+  return reinterpret_cast<MultiKeywordSelector *>(InfoPtr)->getName();
+}
+
+
+namespace {
+  struct SelectorTableImpl {
+    llvm::FoldingSet<MultiKeywordSelector> Table;
+    llvm::BumpPtrAllocator Allocator;
+  };
+} // end anonymous namespace.
+
+static SelectorTableImpl &getSelectorTableImpl(void *P) {
+  return *static_cast<SelectorTableImpl*>(P);
+}
+
+
+Selector SelectorTable::getSelector(unsigned nKeys, IdentifierInfo **IIV) {
+  if (nKeys < 2)
+    return Selector(IIV[0], nKeys);
+
+  SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
+
+  // Unique selector, to guarantee there is one per name.
+  llvm::FoldingSetNodeID ID;
+  MultiKeywordSelector::Profile(ID, IIV, nKeys);
+
+  void *InsertPos = 0;
+  if (MultiKeywordSelector *SI =
+        SelTabImpl.Table.FindNodeOrInsertPos(ID, InsertPos))
+    return Selector(SI);
+
+  // MultiKeywordSelector objects are not allocated with new because they have a
+  // variable size array (for parameter types) at the end of them.
+  unsigned Size = sizeof(MultiKeywordSelector) + nKeys*sizeof(IdentifierInfo *);
+  MultiKeywordSelector *SI =
+    (MultiKeywordSelector*)SelTabImpl.Allocator.Allocate(Size,
+                                         llvm::alignof<MultiKeywordSelector>());
+  new (SI) MultiKeywordSelector(nKeys, IIV);
+  SelTabImpl.Table.InsertNode(SI, InsertPos);
+  return Selector(SI);
+}
+
+SelectorTable::SelectorTable() {
+  Impl = new SelectorTableImpl();
+}
+
+SelectorTable::~SelectorTable() {
+  delete &getSelectorTableImpl(Impl);
+}
+
+const char *clang::getOperatorSpelling(OverloadedOperatorKind Operator) {
+  switch (Operator) {
+  case OO_None:
+  case NUM_OVERLOADED_OPERATORS:
+    return 0;
+      
+#define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
+  case OO_##Name: return Spelling;
+#include "clang/Basic/OperatorKinds.def"
+  }
+  
+  return 0;
+}
+