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+//===--- GlobalModuleIndex.cpp - Global Module Index ------------*- C++ -*-===//
+//
+// 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 GlobalModuleIndex class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ASTReaderInternals.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/OnDiskHashTable.h"
+#include "clang/Serialization/ASTBitCodes.h"
+#include "clang/Serialization/GlobalModuleIndex.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/MapVector.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Bitcode/BitstreamReader.h"
+#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Support/Filesystem.h"
+#include "llvm/Support/LockFileManager.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/PathV2.h"
+using namespace clang;
+using namespace serialization;
+
+//----------------------------------------------------------------------------//
+// Shared constants
+//----------------------------------------------------------------------------//
+namespace {
+ enum {
+ /// \brief The block containing the index.
+ GLOBAL_INDEX_BLOCK_ID = llvm::bitc::FIRST_APPLICATION_BLOCKID
+ };
+
+ /// \brief Describes the record types in the index.
+ enum IndexRecordTypes {
+ /// \brief Contains version information and potentially other metadata,
+ /// used to determine if we can read this global index file.
+ METADATA,
+ /// \brief Describes a module, including its file name and dependencies.
+ MODULE,
+ /// \brief The index for identifiers.
+ IDENTIFIER_INDEX
+ };
+}
+
+/// \brief The name of the global index file.
+static const char * const IndexFileName = "modules.idx";
+
+/// \brief The global index file version.
+static const unsigned CurrentVersion = 1;
+
+//----------------------------------------------------------------------------//
+// Global module index writer.
+//----------------------------------------------------------------------------//
+
+namespace {
+ /// \brief Provides information about a specific module file.
+ struct ModuleFileInfo {
+ /// \brief The numberic ID for this module file.
+ unsigned ID;
+
+ /// \brief The set of modules on which this module depends. Each entry is
+ /// a module ID.
+ SmallVector<unsigned, 4> Dependencies;
+ };
+
+ /// \brief Builder that generates the global module index file.
+ class GlobalModuleIndexBuilder {
+ FileManager &FileMgr;
+
+ /// \brief Mapping from files to module file information.
+ typedef llvm::MapVector<const FileEntry *, ModuleFileInfo> ModuleFilesMap;
+
+ /// \brief Information about each of the known module files.
+ ModuleFilesMap ModuleFiles;
+
+ /// \brief Mapping from identifiers to the list of module file IDs that
+ /// consider this identifier to be interesting.
+ typedef llvm::StringMap<SmallVector<unsigned, 2> > InterestingIdentifierMap;
+
+ /// \brief A mapping from all interesting identifiers to the set of module
+ /// files in which those identifiers are considered interesting.
+ InterestingIdentifierMap InterestingIdentifiers;
+
+ /// \brief Write the block-info block for the global module index file.
+ void emitBlockInfoBlock(llvm::BitstreamWriter &Stream);
+
+ /// \brief Retrieve the module file information for the given file.
+ ModuleFileInfo &getModuleFileInfo(const FileEntry *File) {
+ llvm::MapVector<const FileEntry *, ModuleFileInfo>::iterator Known
+ = ModuleFiles.find(File);
+ if (Known != ModuleFiles.end())
+ return Known->second;
+
+ unsigned NewID = ModuleFiles.size();
+ ModuleFileInfo &Info = ModuleFiles[File];
+ Info.ID = NewID;
+ return Info;
+ }
+
+ public:
+ explicit GlobalModuleIndexBuilder(FileManager &FileMgr) : FileMgr(FileMgr){}
+
+ /// \brief Load the contents of the given module file into the builder.
+ ///
+ /// \returns true if an error occurred, false otherwise.
+ bool loadModuleFile(const FileEntry *File);
+
+ /// \brief Write the index to the given bitstream.
+ void writeIndex(llvm::BitstreamWriter &Stream);
+ };
+}
+
+static void emitBlockID(unsigned ID, const char *Name,
+ llvm::BitstreamWriter &Stream,
+ SmallVectorImpl<uint64_t> &Record) {
+ Record.clear();
+ Record.push_back(ID);
+ Stream.EmitRecord(llvm::bitc::BLOCKINFO_CODE_SETBID, Record);
+
+ // Emit the block name if present.
+ if (Name == 0 || Name[0] == 0) return;
+ Record.clear();
+ while (*Name)
+ Record.push_back(*Name++);
+ Stream.EmitRecord(llvm::bitc::BLOCKINFO_CODE_BLOCKNAME, Record);
+}
+
+static void emitRecordID(unsigned ID, const char *Name,
+ llvm::BitstreamWriter &Stream,
+ SmallVectorImpl<uint64_t> &Record) {
+ Record.clear();
+ Record.push_back(ID);
+ while (*Name)
+ Record.push_back(*Name++);
+ Stream.EmitRecord(llvm::bitc::BLOCKINFO_CODE_SETRECORDNAME, Record);
+}
+
+void
+GlobalModuleIndexBuilder::emitBlockInfoBlock(llvm::BitstreamWriter &Stream) {
+ SmallVector<uint64_t, 64> Record;
+ Stream.EnterSubblock(llvm::bitc::BLOCKINFO_BLOCK_ID, 3);
+
+#define BLOCK(X) emitBlockID(X ## _ID, #X, Stream, Record)
+#define RECORD(X) emitRecordID(X, #X, Stream, Record)
+ BLOCK(GLOBAL_INDEX_BLOCK);
+ RECORD(METADATA);
+ RECORD(MODULE);
+ RECORD(IDENTIFIER_INDEX);
+#undef RECORD
+#undef BLOCK
+
+ Stream.ExitBlock();
+}
+
+namespace clang {
+ class InterestingASTIdentifierLookupTrait
+ : public serialization::reader::ASTIdentifierLookupTraitBase {
+
+ public:
+ /// \brief The identifier and whether it is "interesting".
+ typedef std::pair<StringRef, bool> data_type;
+
+ data_type ReadData(const internal_key_type& k,
+ const unsigned char* d,
+ unsigned DataLen) {
+ // The first bit indicates whether this identifier is interesting.
+ // That's all we care about.
+ using namespace clang::io;
+ unsigned RawID = ReadUnalignedLE32(d);
+ bool IsInteresting = RawID & 0x01;
+ return std::make_pair(k, IsInteresting);
+ }
+ };
+}
+
+bool GlobalModuleIndexBuilder::loadModuleFile(const FileEntry *File) {
+ // Open the module file.
+ OwningPtr<llvm::MemoryBuffer> Buffer;
+ Buffer.reset(FileMgr.getBufferForFile(File));
+ if (!Buffer) {
+ return true;
+ }
+
+ // Initialize the input stream
+ llvm::BitstreamReader InStreamFile;
+ llvm::BitstreamCursor InStream;
+ InStreamFile.init((const unsigned char *)Buffer->getBufferStart(),
+ (const unsigned char *)Buffer->getBufferEnd());
+ InStream.init(InStreamFile);
+
+ // Sniff for the signature.
+ if (InStream.Read(8) != 'C' ||
+ InStream.Read(8) != 'P' ||
+ InStream.Read(8) != 'C' ||
+ InStream.Read(8) != 'H') {
+ return true;
+ }
+
+ // Record this module file and assign it a unique ID (if it doesn't have
+ // one already).
+ unsigned ID = getModuleFileInfo(File).ID;
+
+ // Search for the blocks and records we care about.
+ enum { Outer, ControlBlock, ASTBlock } State = Outer;
+ bool Done = false;
+ while (!Done) {
+ const unsigned Flags = llvm::BitstreamCursor::AF_DontPopBlockAtEnd;
+ llvm::BitstreamEntry Entry = InStream.advance(Flags);
+ switch (Entry.Kind) {
+ case llvm::BitstreamEntry::Error:
+ return true;
+
+ case llvm::BitstreamEntry::Record:
+ // In the outer state, just skip the record. We don't care.
+ if (State == Outer) {
+ InStream.skipRecord(Entry.ID);
+ continue;
+ }
+
+ // Handle potentially-interesting records below.
+ break;
+
+ case llvm::BitstreamEntry::SubBlock:
+ if (State == Outer && Entry.ID == CONTROL_BLOCK_ID) {
+ if (InStream.EnterSubBlock(CONTROL_BLOCK_ID))
+ return true;
+
+ // Found the control block.
+ State = ControlBlock;
+ continue;
+ }
+
+ if (State == Outer && Entry.ID == AST_BLOCK_ID) {
+ if (InStream.EnterSubBlock(AST_BLOCK_ID))
+ return true;
+
+ // Found the AST block.
+ State = ASTBlock;
+ continue;
+
+ }
+
+ if (InStream.SkipBlock())
+ return true;
+
+ continue;
+
+ case llvm::BitstreamEntry::EndBlock:
+ if (State == Outer) {
+ Done = true;
+ }
+ State = Outer;
+ continue;
+ }
+
+ // Read the given record.
+ SmallVector<uint64_t, 64> Record;
+ StringRef Blob;
+ unsigned Code = InStream.readRecord(Entry.ID, Record, &Blob);
+
+ // Handle module dependencies.
+ if (State == ControlBlock && Code == IMPORTS) {
+ // Load each of the imported PCH files.
+ unsigned Idx = 0, N = Record.size();
+ while (Idx < N) {
+ // Read information about the AST file.
+
+ // Skip the imported kind
+ ++Idx;
+
+ // Skip the import location
+ ++Idx;
+
+ // Retrieve the imported file name.
+ unsigned Length = Record[Idx++];
+ SmallString<128> ImportedFile(Record.begin() + Idx,
+ Record.begin() + Idx + Length);
+ Idx += Length;
+
+ // Find the imported module file.
+ const FileEntry *DependsOnFile = FileMgr.getFile(ImportedFile);
+ if (!DependsOnFile)
+ return true;
+
+ // Record the dependency.
+ unsigned DependsOnID = getModuleFileInfo(DependsOnFile).ID;
+ getModuleFileInfo(File).Dependencies.push_back(DependsOnID);
+ }
+
+ continue;
+ }
+
+ // Handle the identifier table
+ if (State == ASTBlock && Code == IDENTIFIER_TABLE && Record[0] > 0) {
+ typedef OnDiskChainedHashTable<InterestingASTIdentifierLookupTrait>
+ InterestingIdentifierTable;
+ llvm::OwningPtr<InterestingIdentifierTable>
+ Table(InterestingIdentifierTable::Create(
+ (const unsigned char *)Blob.data() + Record[0],
+ (const unsigned char *)Blob.data()));
+ for (InterestingIdentifierTable::data_iterator D = Table->data_begin(),
+ DEnd = Table->data_end();
+ D != DEnd; ++D) {
+ std::pair<StringRef, bool> Ident = *D;
+ if (Ident.second)
+ InterestingIdentifiers[Ident.first].push_back(ID);
+ }
+ }
+
+ // FIXME: Handle the selector table.
+
+ // We don't care about this record.
+ }
+
+ return false;
+}
+
+namespace {
+
+/// \brief Trait used to generate the identifier index as an on-disk hash
+/// table.
+class IdentifierIndexWriterTrait {
+public:
+ typedef StringRef key_type;
+ typedef StringRef key_type_ref;
+ typedef SmallVector<unsigned, 2> data_type;
+ typedef const SmallVector<unsigned, 2> &data_type_ref;
+
+ static unsigned ComputeHash(key_type_ref Key) {
+ return llvm::HashString(Key);
+ }
+
+ std::pair<unsigned,unsigned>
+ EmitKeyDataLength(raw_ostream& Out, key_type_ref Key, data_type_ref Data) {
+ unsigned KeyLen = Key.size();
+ unsigned DataLen = Data.size() * 4;
+ clang::io::Emit16(Out, KeyLen);
+ clang::io::Emit16(Out, DataLen);
+ return std::make_pair(KeyLen, DataLen);
+ }
+
+ void EmitKey(raw_ostream& Out, key_type_ref Key, unsigned KeyLen) {
+ Out.write(Key.data(), KeyLen);
+ }
+
+ void EmitData(raw_ostream& Out, key_type_ref Key, data_type_ref Data,
+ unsigned DataLen) {
+ for (unsigned I = 0, N = Data.size(); I != N; ++I)
+ clang::io::Emit32(Out, Data[I]);
+ }
+};
+
+}
+
+void GlobalModuleIndexBuilder::writeIndex(llvm::BitstreamWriter &Stream) {
+ using namespace llvm;
+
+ // Emit the file header.
+ Stream.Emit((unsigned)'B', 8);
+ Stream.Emit((unsigned)'C', 8);
+ Stream.Emit((unsigned)'G', 8);
+ Stream.Emit((unsigned)'I', 8);
+
+ // Write the block-info block, which describes the records in this bitcode
+ // file.
+ emitBlockInfoBlock(Stream);
+
+ Stream.EnterSubblock(GLOBAL_INDEX_BLOCK_ID, 3);
+
+ // Write the metadata.
+ SmallVector<uint64_t, 2> Record;
+ Record.push_back(CurrentVersion);
+ Stream.EmitRecord(METADATA, Record);
+
+ // Write the set of known module files.
+ for (ModuleFilesMap::iterator M = ModuleFiles.begin(),
+ MEnd = ModuleFiles.end();
+ M != MEnd; ++M) {
+ Record.clear();
+ Record.push_back(M->second.ID);
+ Record.push_back(M->first->getSize());
+ Record.push_back(M->first->getModificationTime());
+
+ // File name
+ StringRef Name(M->first->getName());
+ Record.push_back(Name.size());
+ Record.append(Name.begin(), Name.end());
+
+ // Dependencies
+ Record.push_back(M->second.Dependencies.size());
+ Record.append(M->second.Dependencies.begin(), M->second.Dependencies.end());
+ Stream.EmitRecord(MODULE, Record);
+ }
+
+ // Write the identifier -> module file mapping.
+ {
+ OnDiskChainedHashTableGenerator<IdentifierIndexWriterTrait> Generator;
+ IdentifierIndexWriterTrait Trait;
+
+ // Populate the hash table.
+ for (InterestingIdentifierMap::iterator I = InterestingIdentifiers.begin(),
+ IEnd = InterestingIdentifiers.end();
+ I != IEnd; ++I) {
+ Generator.insert(I->first(), I->second, Trait);
+ }
+
+ // Create the on-disk hash table in a buffer.
+ SmallString<4096> IdentifierTable;
+ uint32_t BucketOffset;
+ {
+ llvm::raw_svector_ostream Out(IdentifierTable);
+ // Make sure that no bucket is at offset 0
+ clang::io::Emit32(Out, 0);
+ BucketOffset = Generator.Emit(Out, Trait);
+ }
+
+ // Create a blob abbreviation
+ BitCodeAbbrev *Abbrev = new BitCodeAbbrev();
+ Abbrev->Add(BitCodeAbbrevOp(IDENTIFIER_INDEX));
+ Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
+ Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
+ unsigned IDTableAbbrev = Stream.EmitAbbrev(Abbrev);
+
+ // Write the identifier table
+ Record.clear();
+ Record.push_back(IDENTIFIER_INDEX);
+ Record.push_back(BucketOffset);
+ Stream.EmitRecordWithBlob(IDTableAbbrev, Record, IdentifierTable.str());
+ }
+
+ // FIXME: Selectors.
+
+ Stream.ExitBlock();
+}
+
+GlobalModuleIndex::ErrorCode
+GlobalModuleIndex::writeIndex(FileManager &FileMgr, StringRef Path) {
+ llvm::SmallString<128> IndexPath;
+ IndexPath += Path;
+ llvm::sys::path::append(IndexPath, IndexFileName);
+
+ // Coordinate building the global index file with other processes that might
+ // try to do the same.
+ llvm::LockFileManager Locked(IndexPath);
+ switch (Locked) {
+ case llvm::LockFileManager::LFS_Error:
+ return EC_IOError;
+
+ case llvm::LockFileManager::LFS_Owned:
+ // We're responsible for building the index ourselves. Do so below.
+ break;
+
+ case llvm::LockFileManager::LFS_Shared:
+ // Someone else is responsible for building the index. We don't care
+ // when they finish, so we're done.
+ return EC_Building;
+ }
+
+ // The module index builder.
+ GlobalModuleIndexBuilder Builder(FileMgr);
+
+ // Load each of the module files.
+ llvm::error_code EC;
+ for (llvm::sys::fs::directory_iterator D(Path, EC), DEnd;
+ D != DEnd && !EC;
+ D.increment(EC)) {
+ // If this isn't a module file, we don't care.
+ if (llvm::sys::path::extension(D->path()) != ".pcm") {
+ // ... unless it's a .pcm.lock file, which indicates that someone is
+ // in the process of rebuilding a module. They'll rebuild the index
+ // at the end of that translation unit, so we don't have to.
+ if (llvm::sys::path::extension(D->path()) == ".pcm.lock")
+ return EC_Building;
+
+ continue;
+ }
+
+ // If we can't find the module file, skip it.
+ const FileEntry *ModuleFile = FileMgr.getFile(D->path());
+ if (!ModuleFile)
+ continue;
+
+ // Load this module file.
+ if (Builder.loadModuleFile(ModuleFile))
+ return EC_IOError;
+ }
+
+ // The output buffer, into which the global index will be written.
+ SmallVector<char, 16> OutputBuffer;
+ {
+ llvm::BitstreamWriter OutputStream(OutputBuffer);
+ Builder.writeIndex(OutputStream);
+ }
+
+ // Write the global index file to a temporary file.
+ llvm::SmallString<128> IndexTmpPath;
+ int TmpFD;
+ if (llvm::sys::fs::unique_file(IndexPath + "-%%%%%%%%", TmpFD, IndexTmpPath))
+ return EC_IOError;
+
+ // Open the temporary global index file for output.
+ std::string ErrorInfo;
+ llvm::raw_fd_ostream Out(IndexTmpPath.c_str(), ErrorInfo,
+ llvm::raw_fd_ostream::F_Binary);
+ if (Out.has_error())
+ return EC_IOError;
+
+ // Write the index.
+ Out.write(OutputBuffer.data(), OutputBuffer.size());
+ Out.close();
+ if (Out.has_error())
+ return EC_IOError;
+
+ // Remove the old index file. It isn't relevant any more.
+ bool OldIndexExisted;
+ llvm::sys::fs::remove(IndexPath.str(), OldIndexExisted);
+
+ // Rename the newly-written index file to the proper name.
+ if (llvm::sys::fs::rename(IndexTmpPath.str(), IndexPath.str())) {
+ // Rename failed; just remove the
+ llvm::sys::fs::remove(IndexTmpPath.str(), OldIndexExisted);
+ return EC_IOError;
+ }
+
+ // We're done.
+ return EC_None;
+}
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