PTH: Embed a persistentID side-table in the PTH file that is sorted in the
lexical order of the corresponding identifier strings. This will be used for a forthcoming optimization. This slows down PTH generation time by 7%. We can revert this change if the optimization proves to not be valuable. llvm-svn: 62248
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@ -102,7 +102,7 @@ class VISIBILITY_HIDDEN PTHWriter {
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for ( ; I != E ; ++I) Out << *I;
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}
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std::pair<Offset,Offset> EmitIdentifierTable();
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std::pair<Offset,std::pair<Offset, Offset> > EmitIdentifierTable();
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Offset EmitFileTable();
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PCHEntry LexTokens(Lexer& L);
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void EmitCachedSpellings();
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@ -171,57 +171,66 @@ namespace {
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struct VISIBILITY_HIDDEN IDData {
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const IdentifierInfo* II;
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uint32_t FileOffset;
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const IdentifierTable::const_iterator::value_type* Str;
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};
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class VISIBILITY_HIDDEN CompareIDDataIndex {
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IDData* Table;
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public:
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CompareIDDataIndex(IDData* table) : Table(table) {}
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bool operator()(unsigned i, unsigned j) const {
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// Assume that IdentifierInfo::getName() returns a '\0' terminated string.
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return strcmp(Table[i].II->getName(), Table[j].II->getName()) < 0;
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}
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};
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}
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std::pair<Offset,Offset> PTHWriter::EmitIdentifierTable() {
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const IdentifierTable& T = PP.getIdentifierTable();
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std::pair<Offset,std::pair<Offset,Offset> >
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PTHWriter::EmitIdentifierTable() {
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llvm::BumpPtrAllocator Alloc;
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// Build an inverse map from persistent IDs -> IdentifierInfo*.
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typedef std::vector<IDData> InverseIDMap;
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InverseIDMap IIDMap;
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IIDMap.resize(idcount);
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IDData* IIDMap = Alloc.Allocate<IDData>(idcount);
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// Generate mapping from persistent IDs -> IdentifierInfo*.
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for (IDMap::iterator I=IM.begin(), E=IM.end(); I!=E; ++I) {
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// Decrement by 1 because we are using a vector for the lookup and
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// 0 is reserved for NULL.
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assert(I->second > 0);
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assert(I->second-1 < IIDMap.size());
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IIDMap[I->second-1].II = I->first;
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}
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// Get the string data associated with the IdentifierInfo.
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for (IdentifierTable::const_iterator I=T.begin(), E=T.end(); I!=E; ++I) {
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IDMap::iterator IDI = IM.find(&(I->getValue()));
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if (IDI == IM.end()) continue;
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IIDMap[IDI->second-1].Str = &(*I);
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}
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assert(I->second-1 < idcount);
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unsigned idx = I->second-1;
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IIDMap[idx].II = I->first;
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}
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// We want to write out the strings in lexical order to support binary
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// search of strings to identifiers. Create such a table.
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unsigned *LexicalOrder = Alloc.Allocate<unsigned>(idcount);
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for (unsigned i = 0; i < idcount ; ++i ) LexicalOrder[i] = i;
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std::sort(LexicalOrder, LexicalOrder+idcount, CompareIDDataIndex(IIDMap));
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// Write out the lexically-sorted table of persistent ids.
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Offset LexicalOff = Out.tell();
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for (unsigned i = 0; i < idcount ; ++i) Emit32(LexicalOrder[i]);
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// Write out the string data itself.
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Offset DataOff = Out.tell();
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for (InverseIDMap::iterator I=IIDMap.begin(), E=IIDMap.end(); I!=E; ++I) {
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// Record the location for this data.
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I->FileOffset = Out.tell();
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// Write out the keyword.
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unsigned len = I->Str->getKeyLength();
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for (unsigned i = 0; i < idcount; ++i) {
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IDData& d = IIDMap[i];
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d.FileOffset = Out.tell(); // Record the location for this data.
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unsigned len = d.II->getLength(); // Write out the string length.
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Emit32(len);
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const char* buf = I->Str->getKeyData();
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const char* buf = d.II->getName(); // Write out the string data.
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EmitBuf(buf, buf+len);
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}
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// Now emit the table mapping from persistent IDs to PTH file offsets.
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Offset IDOff = Out.tell();
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// Emit the number of identifiers.
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Emit32(idcount);
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Emit32(idcount); // Emit the number of identifiers.
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for (unsigned i = 0 ; i < idcount; ++i) Emit32(IIDMap[i].FileOffset);
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for (InverseIDMap::iterator I=IIDMap.begin(), E=IIDMap.end(); I!=E; ++I)
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Emit32(I->FileOffset);
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return std::make_pair(DataOff, IDOff);
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return std::make_pair(DataOff, std::make_pair(IDOff, LexicalOff));
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}
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Offset PTHWriter::EmitFileTable() {
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@ -473,7 +482,8 @@ void PTHWriter::GeneratePTH() {
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}
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// Write out the identifier table.
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std::pair<Offset,Offset> IdTableOff = EmitIdentifierTable();
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const std::pair<Offset, std::pair<Offset,Offset> >& IdTableOff
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= EmitIdentifierTable();
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// Write out the cached strings table.
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EmitCachedSpellings();
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@ -483,7 +493,8 @@ void PTHWriter::GeneratePTH() {
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// Finally, write out the offset table at the end.
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Emit32(IdTableOff.first);
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Emit32(IdTableOff.second);
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Emit32(IdTableOff.second.first);
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Emit32(IdTableOff.second.second);
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Emit32(FileTableOff);
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}
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@ -538,11 +538,12 @@ PTHManager* PTHManager::Create(const std::string& file, Preprocessor& PP) {
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// Compute the address of the index table at the end of the PTH file.
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// This table contains the offset of the file lookup table, the
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// persistent ID -> identifer data table.
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const char* EndTable = BufEnd - sizeof(uint32_t)*3;
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// FIXME: We should just embed this offset in the PTH file.
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const char* EndTable = BufEnd - sizeof(uint32_t)*4;
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// Construct the file lookup table. This will be used for mapping from
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// FileEntry*'s to cached tokens.
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const char* FileTableOffset = EndTable + sizeof(uint32_t)*2;
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const char* FileTableOffset = EndTable + sizeof(uint32_t)*3;
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const char* FileTable = BufBeg + Read32(FileTableOffset);
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if (!(FileTable > BufBeg && FileTable < BufEnd)) {
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