//===-- ArchiveWriter.cpp - Write LLVM archive files ----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Builds up an LLVM archive file (.a) containing LLVM bitcode.
//
//===----------------------------------------------------------------------===//
#include "ArchiveInternals.h"
#include "llvm/Module.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Process.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/system_error.h"
#include <fstream>
#include <ostream>
#include <iomanip>
using namespace llvm;
// Write an integer using variable bit rate encoding. This saves a few bytes
// per entry in the symbol table.
static inline void writeInteger(unsigned num, std::ofstream& ARFile) {
while (1) {
if (num < 0x80) { // done?
ARFile << (unsigned char)num;
return;
}
// Nope, we are bigger than a character, output the next 7 bits and set the
// high bit to say that there is more coming...
ARFile << (unsigned char)(0x80 | ((unsigned char)num & 0x7F));
num >>= 7; // Shift out 7 bits now...
}
}
// Compute how many bytes are taken by a given VBR encoded value. This is needed
// to pre-compute the size of the symbol table.
static inline unsigned numVbrBytes(unsigned num) {
// Note that the following nested ifs are somewhat equivalent to a binary
// search. We split it in half by comparing against 2^14 first. This allows
// most reasonable values to be done in 2 comparisons instead of 1 for
// small ones and four for large ones. We expect this to access file offsets
// in the 2^10 to 2^24 range and symbol lengths in the 2^0 to 2^8 range,
// so this approach is reasonable.
if (num < 1<<14) {
if (num < 1<<7)
return 1;
else
return 2;
}
if (num < 1<<21)
return 3;
if (num < 1<<28)
return 4;
return 5; // anything >= 2^28 takes 5 bytes
}
// Create an empty archive.
Archive* Archive::CreateEmpty(const sys::Path& FilePath, LLVMContext& C) {
Archive* result = new Archive(FilePath, C);
return result;
}
// Fill the ArchiveMemberHeader with the information from a member. If
// TruncateNames is true, names are flattened to 15 chars or less. The sz field
// is provided here instead of coming from the mbr because the member might be
// stored compressed and the compressed size is not the ArchiveMember's size.
// Furthermore compressed files have negative size fields to identify them as
// compressed.
bool
Archive::fillHeader(const ArchiveMember &mbr, ArchiveMemberHeader& hdr,
int sz, bool TruncateNames) const {
// Set the permissions mode, uid and gid
hdr.init();
char buffer[32];
sprintf(buffer, "%-8o", mbr.getMode());
memcpy(hdr.mode,buffer,8);
sprintf(buffer, "%-6u", mbr.getUser());
memcpy(hdr.uid,buffer,6);
sprintf(buffer, "%-6u", mbr.getGroup());
memcpy(hdr.gid,buffer,6);
// Set the last modification date
uint64_t secondsSinceEpoch = mbr.getModTime().toEpochTime();
sprintf(buffer,"%-12u", unsigned(secondsSinceEpoch));
memcpy(hdr.date,buffer,12);
// Get rid of trailing blanks in the name
std::string mbrPath = mbr.getPath().str();
size_t mbrLen = mbrPath.length();
while (mbrLen > 0 && mbrPath[mbrLen-1] == ' ') {
mbrPath.erase(mbrLen-1,1);
mbrLen--;
}
// Set the name field in one of its various flavors.
bool writeLongName = false;
if (mbr.isStringTable()) {
memcpy(hdr.name,ARFILE_STRTAB_NAME,16);
} else if (mbr.isSVR4SymbolTable()) {
memcpy(hdr.name,ARFILE_SVR4_SYMTAB_NAME,16);
} else if (mbr.isBSD4SymbolTable()) {
memcpy(hdr.name,ARFILE_BSD4_SYMTAB_NAME,16);
} else if (mbr.isLLVMSymbolTable()) {
memcpy(hdr.name,ARFILE_LLVM_SYMTAB_NAME,16);
} else if (TruncateNames) {
const char* nm = mbrPath.c_str();
unsigned len = mbrPath.length();
size_t slashpos = mbrPath.rfind('/');
if (slashpos != std::string::npos) {
nm += slashpos + 1;
len -= slashpos +1;
}
if (len > 15)
len = 15;
memcpy(hdr.name,nm,len);
hdr.name[len] = '/';
} else if (mbrPath.length() < 16 && mbrPath.find('/') == std::string::npos) {
memcpy(hdr.name,mbrPath.c_str(),mbrPath.length());
hdr.name[mbrPath.length()] = '/';
} else {
std::string nm = "#1/";
nm += utostr(mbrPath.length());
memcpy(hdr.name,nm.data(),nm.length());
if (sz < 0)
sz -= mbrPath.length();
else
sz += mbrPath.length();
writeLongName = true;
}
// Set the size field
if (sz < 0) {
buffer[0] = '-';
sprintf(&buffer[1],"%-9u",(unsigned)-sz);
} else {
sprintf(buffer, "%-10u", (unsigned)sz);
}
memcpy(hdr.size,buffer,10);
return writeLongName;
}
// Insert a file into the archive before some other member. This also takes care
// of extracting the necessary flags and information from the file.
bool
Archive::addFileBefore(const sys::Path& filePath, iterator where,
std::string* ErrMsg) {
bool Exists;
if (sys::fs::exists(filePath.str(), Exists) || !Exists) {
if (ErrMsg)
*ErrMsg = "Can not add a non-existent file to archive";
return true;
}
ArchiveMember* mbr = new ArchiveMember(this);
mbr->data = 0;
mbr->path = filePath;
const sys::FileStatus *FSInfo = mbr->path.getFileStatus(false, ErrMsg);
if (!FSInfo) {
delete mbr;
return true;
}
mbr->info = *FSInfo;
unsigned flags = 0;
bool hasSlash = filePath.str().find('/') != std::string::npos;
if (hasSlash)
flags |= ArchiveMember::HasPathFlag;
if (hasSlash || filePath.str().length() > 15)
flags |= ArchiveMember::HasLongFilenameFlag;
sys::fs::file_magic type;
if (sys::fs::identify_magic(mbr->path.str(), type))
type = sys::fs::file_magic::unknown;
switch (type) {
case sys::fs::file_magic::bitcode:
flags |= ArchiveMember::BitcodeFlag;
break;
default:
break;
}
mbr->flags = flags;
members.insert(where,mbr);
return false;
}
// Write one member out to the file.
bool
Archive::writeMember(
const ArchiveMember& member,
std::ofstream& ARFile,
bool CreateSymbolTable,
bool TruncateNames,
bool ShouldCompress,
std::string* ErrMsg
) {
unsigned filepos = ARFile.tellp();
filepos -= 8;
// Get the data and its size either from the
// member's in-memory data or directly from the file.
size_t fSize = member.getSize();
const char *data = (const char*)member.getData();
MemoryBuffer *mFile = 0;
if (!data) {
OwningPtr<MemoryBuffer> File;
if (error_code ec = MemoryBuffer::getFile(member.getPath().c_str(), File)) {
if (ErrMsg)
*ErrMsg = ec.message();
return true;
}
mFile = File.take();
data = mFile->getBufferStart();
fSize = mFile->getBufferSize();
}
// Now that we have the data in memory, update the
// symbol table if it's a bitcode file.
if (CreateSymbolTable && member.isBitcode()) {
std::vector<std::string> symbols;
std::string FullMemberName = archPath.str() + "(" + member.getPath().str()
+ ")";
Module* M =
GetBitcodeSymbols(data, fSize, FullMemberName, Context, symbols, ErrMsg);
// If the bitcode parsed successfully
if ( M ) {
for (std::vector<std::string>::iterator SI = symbols.begin(),
SE = symbols.end(); SI != SE; ++SI) {
std::pair<SymTabType::iterator,bool> Res =
symTab.insert(std::make_pair(*SI,filepos));
if (Res.second) {
symTabSize += SI->length() +
numVbrBytes(SI->length()) +
numVbrBytes(filepos);
}
}
// We don't need this module any more.
delete M;
} else {
delete mFile;
if (ErrMsg)
*ErrMsg = "Can't parse bitcode member: " + member.getPath().str()
+ ": " + *ErrMsg;
return true;
}
}
int hdrSize = fSize;
// Compute the fields of the header
ArchiveMemberHeader Hdr;
bool writeLongName = fillHeader(member,Hdr,hdrSize,TruncateNames);
// Write header to archive file
ARFile.write((char*)&Hdr, sizeof(Hdr));
// Write the long filename if its long
if (writeLongName) {
ARFile.write(member.getPath().str().data(),
member.getPath().str().length());
}
// Write the (possibly compressed) member's content to the file.
ARFile.write(data,fSize);
// Make sure the member is an even length
if ((ARFile.tellp() & 1) == 1)
ARFile << ARFILE_PAD;
// Close the mapped file if it was opened
delete mFile;
return false;
}
// Write out the LLVM symbol table as an archive member to the file.
void
Archive::writeSymbolTable(std::ofstream& ARFile) {
// Construct the symbol table's header
ArchiveMemberHeader Hdr;
Hdr.init();
memcpy(Hdr.name,ARFILE_LLVM_SYMTAB_NAME,16);
uint64_t secondsSinceEpoch = sys::TimeValue::now().toEpochTime();
char buffer[32];
sprintf(buffer, "%-8o", 0644);
memcpy(Hdr.mode,buffer,8);
sprintf(buffer, "%-6u", sys::Process::GetCurrentUserId());
memcpy(Hdr.uid,buffer,6);
sprintf(buffer, "%-6u", sys::Process::GetCurrentGroupId());
memcpy(Hdr.gid,buffer,6);
sprintf(buffer,"%-12u", unsigned(secondsSinceEpoch));
memcpy(Hdr.date,buffer,12);
sprintf(buffer,"%-10u",symTabSize);
memcpy(Hdr.size,buffer,10);
// Write the header
ARFile.write((char*)&Hdr, sizeof(Hdr));
#ifndef NDEBUG
// Save the starting position of the symbol tables data content.
unsigned startpos = ARFile.tellp();
#endif
// Write out the symbols sequentially
for ( Archive::SymTabType::iterator I = symTab.begin(), E = symTab.end();
I != E; ++I)
{
// Write out the file index
writeInteger(I->second, ARFile);
// Write out the length of the symbol
writeInteger(I->first.length(), ARFile);
// Write out the symbol
ARFile.write(I->first.data(), I->first.length());
}
#ifndef NDEBUG
// Now that we're done with the symbol table, get the ending file position
unsigned endpos = ARFile.tellp();
#endif
// Make sure that the amount we wrote is what we pre-computed. This is
// critical for file integrity purposes.
assert(endpos - startpos == symTabSize && "Invalid symTabSize computation");
// Make sure the symbol table is even sized
if (symTabSize % 2 != 0 )
ARFile << ARFILE_PAD;
}
// Write the entire archive to the file specified when the archive was created.
// This writes to a temporary file first. Options are for creating a symbol
// table, flattening the file names (no directories, 15 chars max) and
// compressing each archive member.
bool
Archive::writeToDisk(bool CreateSymbolTable, bool TruncateNames, bool Compress,
std::string* ErrMsg)
{
// Make sure they haven't opened up the file, not loaded it,
// but are now trying to write it which would wipe out the file.
if (members.empty() && mapfile && mapfile->getBufferSize() > 8) {
if (ErrMsg)
*ErrMsg = "Can't write an archive not opened for writing";
return true;
}
// Create a temporary file to store the archive in
sys::Path TmpArchive = archPath;
if (TmpArchive.createTemporaryFileOnDisk(ErrMsg))
return true;
// Make sure the temporary gets removed if we crash
sys::RemoveFileOnSignal(TmpArchive);
// Create archive file for output.
std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
std::ios::binary;
std::ofstream ArchiveFile(TmpArchive.c_str(), io_mode);
// Check for errors opening or creating archive file.
if (!ArchiveFile.is_open() || ArchiveFile.bad()) {
TmpArchive.eraseFromDisk();
if (ErrMsg)
*ErrMsg = "Error opening archive file: " + archPath.str();
return true;
}
// If we're creating a symbol table, reset it now
if (CreateSymbolTable) {
symTabSize = 0;
symTab.clear();
}
// Write magic string to archive.
ArchiveFile << ARFILE_MAGIC;
// Loop over all member files, and write them out. Note that this also
// builds the symbol table, symTab.
for (MembersList::iterator I = begin(), E = end(); I != E; ++I) {
if (writeMember(*I, ArchiveFile, CreateSymbolTable,
TruncateNames, Compress, ErrMsg)) {
TmpArchive.eraseFromDisk();
ArchiveFile.close();
return true;
}
}
// Close archive file.
ArchiveFile.close();
// Write the symbol table
if (CreateSymbolTable) {
// At this point we have written a file that is a legal archive but it
// doesn't have a symbol table in it. To aid in faster reading and to
// ensure compatibility with other archivers we need to put the symbol
// table first in the file. Unfortunately, this means mapping the file
// we just wrote back in and copying it to the destination file.
sys::Path FinalFilePath = archPath;
// Map in the archive we just wrote.
{
OwningPtr<MemoryBuffer> arch;
if (error_code ec = MemoryBuffer::getFile(TmpArchive.c_str(), arch)) {
if (ErrMsg)
*ErrMsg = ec.message();
return true;
}
const char* base = arch->getBufferStart();
// Open another temporary file in order to avoid invalidating the
// mmapped data
if (FinalFilePath.createTemporaryFileOnDisk(ErrMsg))
return true;
sys::RemoveFileOnSignal(FinalFilePath);
std::ofstream FinalFile(FinalFilePath.c_str(), io_mode);
if (!FinalFile.is_open() || FinalFile.bad()) {
TmpArchive.eraseFromDisk();
if (ErrMsg)
*ErrMsg = "Error opening archive file: " + FinalFilePath.str();
return true;
}
// Write the file magic number
FinalFile << ARFILE_MAGIC;
// If there is a foreign symbol table, put it into the file now. Most
// ar(1) implementations require the symbol table to be first but llvm-ar
// can deal with it being after a foreign symbol table. This ensures
// compatibility with other ar(1) implementations as well as allowing the
// archive to store both native .o and LLVM .bc files, both indexed.
if (foreignST) {
if (writeMember(*foreignST, FinalFile, false, false, false, ErrMsg)) {
FinalFile.close();
TmpArchive.eraseFromDisk();
return true;
}
}
// Put out the LLVM symbol table now.
writeSymbolTable(FinalFile);
// Copy the temporary file contents being sure to skip the file's magic
// number.
FinalFile.write(base + sizeof(ARFILE_MAGIC)-1,
arch->getBufferSize()-sizeof(ARFILE_MAGIC)+1);
// Close up shop
FinalFile.close();
} // free arch.
// Move the final file over top of TmpArchive
if (FinalFilePath.renamePathOnDisk(TmpArchive, ErrMsg))
return true;
}
// Before we replace the actual archive, we need to forget all the
// members, since they point to data in that old archive. We need to do
// this because we cannot replace an open file on Windows.
cleanUpMemory();
if (TmpArchive.renamePathOnDisk(archPath, ErrMsg))
return true;
// Set correct read and write permissions after temporary file is moved
// to final destination path.
if (archPath.makeReadableOnDisk(ErrMsg))
return true;
if (archPath.makeWriteableOnDisk(ErrMsg))
return true;
return false;
}
