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//===--- 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 <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
};
}
/// 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;
// 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 = getName();
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 {
std::string Result;
unsigned Length = 0;
for (keyword_iterator I = keyword_begin(), E = keyword_end(); I != E; ++I) {
if (*I)
Length += (*I)->getLength();
++Length; // :
}
Result.reserve(Length);
for (keyword_iterator I = keyword_begin(), E = keyword_end(); I != E; ++I) {
if (*I)
Result.insert(Result.end(), (*I)->getName(),
(*I)->getName()+(*I)->getLength());
Result.push_back(':');
}
return Result;
}
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();
std::string Res = II ? II->getName() : "";
Res += ":";
return Res;
}
// 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);
}