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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"
#include <cstdio>
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.
INDEX_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 reader.
//----------------------------------------------------------------------------//
namespace {
/// \brief Trait used to read the identifier index from the on-disk hash
/// table.
class IdentifierIndexReaderTrait {
public:
typedef StringRef external_key_type;
typedef StringRef internal_key_type;
typedef SmallVector<unsigned, 2> data_type;
static bool EqualKey(const internal_key_type& a, const internal_key_type& b) {
return a == b;
}
static unsigned ComputeHash(const internal_key_type& a) {
return llvm::HashString(a);
}
static std::pair<unsigned, unsigned>
ReadKeyDataLength(const unsigned char*& d) {
using namespace clang::io;
unsigned KeyLen = ReadUnalignedLE16(d);
unsigned DataLen = ReadUnalignedLE16(d);
return std::make_pair(KeyLen, DataLen);
}
static const internal_key_type&
GetInternalKey(const external_key_type& x) { return x; }
static const external_key_type&
GetExternalKey(const internal_key_type& x) { return x; }
static internal_key_type ReadKey(const unsigned char* d, unsigned n) {
return StringRef((const char *)d, n);
}
static data_type ReadData(const internal_key_type& k,
const unsigned char* d,
unsigned DataLen) {
using namespace clang::io;
data_type Result;
while (DataLen > 0) {
unsigned ID = ReadUnalignedLE32(d);
Result.push_back(ID);
DataLen -= 4;
}
return Result;
}
};
typedef OnDiskChainedHashTable<IdentifierIndexReaderTrait> IdentifierIndexTable;
/// \brief Module information as it was loaded from the index file.
struct LoadedModuleInfo {
const FileEntry *File;
SmallVector<unsigned, 2> Dependencies;
SmallVector<unsigned, 2> ImportedBy;
};
}
GlobalModuleIndex::GlobalModuleIndex(FileManager &FileMgr,
llvm::MemoryBuffer *Buffer,
llvm::BitstreamCursor Cursor)
: Buffer(Buffer), IdentifierIndex(),
NumIdentifierLookups(), NumIdentifierLookupHits()
{
typedef llvm::DenseMap<unsigned, LoadedModuleInfo> LoadedModulesMap;
LoadedModulesMap LoadedModules;
// Read the global index.
unsigned LargestID = 0;
bool InGlobalIndexBlock = false;
bool Done = false;
bool AnyOutOfDate = false;
while (!Done) {
llvm::BitstreamEntry Entry = Cursor.advance();
switch (Entry.Kind) {
case llvm::BitstreamEntry::Error:
return;
case llvm::BitstreamEntry::EndBlock:
if (InGlobalIndexBlock) {
InGlobalIndexBlock = false;
Done = true;
continue;
}
return;
case llvm::BitstreamEntry::Record:
// Entries in the global index block are handled below.
if (InGlobalIndexBlock)
break;
return;
case llvm::BitstreamEntry::SubBlock:
if (!InGlobalIndexBlock && Entry.ID == GLOBAL_INDEX_BLOCK_ID) {
if (Cursor.EnterSubBlock(GLOBAL_INDEX_BLOCK_ID))
return;
InGlobalIndexBlock = true;
} else if (Cursor.SkipBlock()) {
return;
}
continue;
}
SmallVector<uint64_t, 64> Record;
StringRef Blob;
switch ((IndexRecordTypes)Cursor.readRecord(Entry.ID, Record, &Blob)) {
case INDEX_METADATA:
// Make sure that the version matches.
if (Record.size() < 1 || Record[0] != CurrentVersion)
return;
break;
case MODULE: {
unsigned Idx = 0;
unsigned ID = Record[Idx++];
if (ID > LargestID)
LargestID = ID;
off_t Size = Record[Idx++];
time_t ModTime = Record[Idx++];
// File name.
unsigned NameLen = Record[Idx++];
llvm::SmallString<64> FileName(Record.begin() + Idx,
Record.begin() + Idx + NameLen);
Idx += NameLen;
// Dependencies
unsigned NumDeps = Record[Idx++];
llvm::SmallVector<unsigned, 2>
Dependencies(Record.begin() + Idx, Record.begin() + Idx + NumDeps);
// Find the file. If we can't find it, ignore it.
const FileEntry *File = FileMgr.getFile(FileName, /*openFile=*/false,
/*cacheFailure=*/false);
if (!File) {
AnyOutOfDate = true;
break;
}
// If the module file is newer than the index, ignore it.
if (File->getSize() != Size || File->getModificationTime() != ModTime) {
AnyOutOfDate = true;
break;
}
// Record this module. The dependencies will be resolved later.
LoadedModuleInfo &Info = LoadedModules[ID];
Info.File = File;
Info.Dependencies.swap(Dependencies);
break;
}
case IDENTIFIER_INDEX:
// Wire up the identifier index.
if (Record[0]) {
IdentifierIndex = IdentifierIndexTable::Create(
(const unsigned char *)Blob.data() + Record[0],
(const unsigned char *)Blob.data(),
IdentifierIndexReaderTrait());
}
break;
}
}
// If there are any modules that have gone out-of-date, prune out any modules
// that depend on them.
if (AnyOutOfDate) {
// First, build back links in the module dependency graph.
SmallVector<unsigned, 4> Stack;
for (LoadedModulesMap::iterator LM = LoadedModules.begin(),
LMEnd = LoadedModules.end();
LM != LMEnd; ++LM) {
unsigned ID = LM->first;
// If this module is out-of-date, push it onto the stack.
if (LM->second.File == 0)
Stack.push_back(ID);
for (unsigned I = 0, N = LM->second.Dependencies.size(); I != N; ++I) {
unsigned DepID = LM->second.Dependencies[I];
LoadedModulesMap::iterator Known = LoadedModules.find(DepID);
if (Known == LoadedModules.end() || !Known->second.File) {
// The dependency was out-of-date, so mark us as out of date.
// This is just an optimization.
if (LM->second.File)
Stack.push_back(ID);
LM->second.File = 0;
continue;
}
// Record this reverse dependency.
Known->second.ImportedBy.push_back(ID);
}
}
// Second, walk the back links from out-of-date modules to those modules
// that depend on them, making those modules out-of-date as well.
while (!Stack.empty()) {
unsigned ID = Stack.back();
Stack.pop_back();
LoadedModuleInfo &Info = LoadedModules[ID];
for (unsigned I = 0, N = Info.ImportedBy.size(); I != N; ++I) {
unsigned FromID = Info.ImportedBy[I];
if (LoadedModules[FromID].File) {
LoadedModules[FromID].File = 0;
Stack.push_back(FromID);
}
}
}
}
// Allocate the vector containing information about all of the modules.
Modules.resize(LargestID + 1);
for (LoadedModulesMap::iterator LM = LoadedModules.begin(),
LMEnd = LoadedModules.end();
LM != LMEnd; ++LM) {
if (!LM->second.File)
continue;
Modules[LM->first].File = LM->second.File;
// Resolve dependencies. Drop any we can't resolve due to out-of-date
// module files.
for (unsigned I = 0, N = LM->second.Dependencies.size(); I != N; ++I) {
unsigned DepID = LM->second.Dependencies[I];
LoadedModulesMap::iterator Known = LoadedModules.find(DepID);
if (Known == LoadedModules.end() || !Known->second.File)
continue;
Modules[LM->first].Dependencies.push_back(Known->second.File);
}
}
}
GlobalModuleIndex::~GlobalModuleIndex() { }
std::pair<GlobalModuleIndex *, GlobalModuleIndex::ErrorCode>
GlobalModuleIndex::readIndex(FileManager &FileMgr, StringRef Path) {
// Load the index file, if it's there.
llvm::SmallString<128> IndexPath;
IndexPath += Path;
llvm::sys::path::append(IndexPath, IndexFileName);
llvm::OwningPtr<llvm::MemoryBuffer> Buffer(
FileMgr.getBufferForFile(IndexPath));
if (!Buffer)
return std::make_pair((GlobalModuleIndex *)0, EC_NotFound);
/// \brief The bitstream reader from which we'll read the AST file.
llvm::BitstreamReader Reader((const unsigned char *)Buffer->getBufferStart(),
(const unsigned char *)Buffer->getBufferEnd());
/// \brief The main bitstream cursor for the main block.
llvm::BitstreamCursor Cursor(Reader);
// Sniff for the signature.
if (Cursor.Read(8) != 'B' ||
Cursor.Read(8) != 'C' ||
Cursor.Read(8) != 'G' ||
Cursor.Read(8) != 'I') {
return std::make_pair((GlobalModuleIndex *)0, EC_IOError);
}
return std::make_pair(new GlobalModuleIndex(FileMgr, Buffer.take(), Cursor),
EC_None);
}
void GlobalModuleIndex::getKnownModules(
SmallVectorImpl<const FileEntry *> &ModuleFiles) {
ModuleFiles.clear();
for (unsigned I = 0, N = Modules.size(); I != N; ++I) {
if (Modules[I].File)
ModuleFiles.push_back(Modules[I].File);
}
}
void GlobalModuleIndex::getModuleDependencies(
const clang::FileEntry *ModuleFile,
SmallVectorImpl<const clang::FileEntry *> &Dependencies) {
// If the file -> index mapping is empty, populate it now.
if (ModulesByFile.empty()) {
for (unsigned I = 0, N = Modules.size(); I != N; ++I) {
if (Modules[I].File)
ModulesByFile[Modules[I].File] = I;
}
}
// Look for information about this module file.
llvm::DenseMap<const FileEntry *, unsigned>::iterator Known
= ModulesByFile.find(ModuleFile);
if (Known == ModulesByFile.end())
return;
// Record dependencies.
Dependencies = Modules[Known->second].Dependencies;
}
bool GlobalModuleIndex::lookupIdentifier(StringRef Name, HitSet &Hits) {
Hits.clear();
// If there's no identifier index, there is nothing we can do.
if (!IdentifierIndex)
return false;
// Look into the identifier index.
++NumIdentifierLookups;
IdentifierIndexTable &Table
= *static_cast<IdentifierIndexTable *>(IdentifierIndex);
IdentifierIndexTable::iterator Known = Table.find(Name);
if (Known == Table.end()) {
return true;
}
SmallVector<unsigned, 2> ModuleIDs = *Known;
for (unsigned I = 0, N = ModuleIDs.size(); I != N; ++I) {
unsigned ID = ModuleIDs[I];
if (ID >= Modules.size() || !Modules[ID].File)
continue;
Hits.insert(Modules[ID].File);
}
++NumIdentifierLookupHits;
return true;
}
void GlobalModuleIndex::printStats() {
std::fprintf(stderr, "*** Global Module Index Statistics:\n");
if (NumIdentifierLookups) {
fprintf(stderr, " %u / %u identifier lookups succeeded (%f%%)\n",
NumIdentifierLookupHits, NumIdentifierLookups,
(double)NumIdentifierLookupHits*100.0/NumIdentifierLookups);
}
std::fprintf(stderr, "\n");
}
//----------------------------------------------------------------------------//
// 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(INDEX_METADATA);
RECORD(MODULE);
RECORD(IDENTIFIER_INDEX);
#undef RECORD
#undef BLOCK
Stream.ExitBlock();
}
namespace {
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;
std::string ErrorStr;
Buffer.reset(FileMgr.getBufferForFile(File, &ErrorStr, /*isVolatile=*/true));
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 { Other, ControlBlock, ASTBlock } State = Other;
bool Done = false;
while (!Done) {
llvm::BitstreamEntry Entry = InStream.advance();
switch (Entry.Kind) {
case llvm::BitstreamEntry::Error:
Done = true;
continue;
case llvm::BitstreamEntry::Record:
// In the 'other' state, just skip the record. We don't care.
if (State == Other) {
InStream.skipRecord(Entry.ID);
continue;
}
// Handle potentially-interesting records below.
break;
case llvm::BitstreamEntry::SubBlock:
if (Entry.ID == CONTROL_BLOCK_ID) {
if (InStream.EnterSubBlock(CONTROL_BLOCK_ID))
return true;
// Found the control block.
State = ControlBlock;
continue;
}
if (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:
State = Other;
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, /*openFile=*/false,
/*cacheFailure=*/false);
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);
else
(void)InterestingIdentifiers[Ident.first];
}
}
// 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(INDEX_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());
}
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.
llvm::raw_fd_ostream Out(TmpFD, true);
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;
}