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llvm-6502/lib/Bytecode/Archive/ArchiveWriter.cpp
Reid Spencer a229c5cce7 Final Changes For PR495:
This chagne just renames some sys::Path methods to ensure they are not
misused. The Path documentation now divides methods into two dimensions:
Path/Disk and accessor/mutator. Path accessors and mutators only operate
on the Path object itself without making any disk accesses. Disk accessors
and mutators will also access or modify the file system. Because of the
potentially destructive nature of disk mutators, it was decided that all
such methods should end in the work "Disk" to ensure the user recognizes
that the change will occur on the file system. This patch makes that
change. The method name changes are:

makeReadable        -> makeReadableOnDisk
makeWriteable       -> makeWriteableOnDisk
makeExecutable      -> makeExecutableOnDisk
setStatusInfo       -> setStatusInfoOnDisk
createDirectory     -> createDirectoryOnDisk
createFile          -> createFileOnDisk
createTemporaryFile -> createTemporaryFileOnDisk
destroy             -> eraseFromDisk
rename              -> renamePathOnDisk

These changes pass the Linux Deja Gnu tests.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22354 91177308-0d34-0410-b5e6-96231b3b80d8
2005-07-08 03:08:58 +00:00

467 lines
15 KiB
C++

//===-- ArchiveWriter.cpp - Write LLVM archive files ----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Reid Spencer and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Builds up an LLVM archive file (.a) containing LLVM bytecode.
//
//===----------------------------------------------------------------------===//
#include "ArchiveInternals.h"
#include "llvm/Bytecode/Reader.h"
#include "llvm/Support/Compressor.h"
#include "llvm/System/Signals.h"
#include "llvm/System/Process.h"
#include <fstream>
#include <iostream>
#include <iomanip>
using namespace llvm;
// Write an integer using variable bit rate encoding. This saves a few bytes
// per entry in the symbol table.
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.
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 ) {
Archive* result = new Archive(FilePath,false);
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().toString();
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.
void
Archive::addFileBefore(const sys::Path& filePath, iterator where) {
assert(filePath.exists() && "Can't add a non-existent file");
ArchiveMember* mbr = new ArchiveMember(this);
mbr->data = 0;
mbr->path = filePath;
mbr->path.getStatusInfo(mbr->info);
unsigned flags = 0;
bool hasSlash = filePath.toString().find('/') != std::string::npos;
if (hasSlash)
flags |= ArchiveMember::HasPathFlag;
if (hasSlash || filePath.toString().length() > 15)
flags |= ArchiveMember::HasLongFilenameFlag;
std::string magic;
mbr->path.getMagicNumber(magic,4);
switch (sys::IdentifyFileType(magic.c_str(),4)) {
case sys::BytecodeFileType:
flags |= ArchiveMember::BytecodeFlag;
break;
case sys::CompressedBytecodeFileType:
flags |= ArchiveMember::CompressedBytecodeFlag;
break;
default:
break;
}
mbr->flags = flags;
members.insert(where,mbr);
}
// Write one member out to the file.
void
Archive::writeMember(
const ArchiveMember& member,
std::ofstream& ARFile,
bool CreateSymbolTable,
bool TruncateNames,
bool ShouldCompress
) {
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();
sys::MappedFile* mFile = 0;
if (!data) {
mFile = new sys::MappedFile(member.getPath());
data = (const char*) mFile->map();
fSize = mFile->size();
}
// Now that we have the data in memory, update the
// symbol table if its a bytecode file.
if (CreateSymbolTable &&
(member.isBytecode() || member.isCompressedBytecode())) {
std::vector<std::string> symbols;
std::string FullMemberName = archPath.toString() + "(" +
member.getPath().toString()
+ ")";
ModuleProvider* MP = GetBytecodeSymbols(
(const unsigned char*)data,fSize,FullMemberName, symbols);
// If the bytecode parsed successfully
if ( MP ) {
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 MP;
} else {
throw std::string("Can't parse bytecode member: ") +
member.getPath().toString();
}
}
// Determine if we actually should compress this member
bool willCompress =
(ShouldCompress &&
!member.isCompressed() &&
!member.isCompressedBytecode() &&
!member.isLLVMSymbolTable() &&
!member.isSVR4SymbolTable() &&
!member.isBSD4SymbolTable());
// Perform the compression. Note that if the file is uncompressed bytecode
// then we turn the file into compressed bytecode rather than treating it as
// compressed data. This is necessary since it allows us to determine that the
// file contains bytecode instead of looking like a regular compressed data
// member. A compressed bytecode file has its content compressed but has a
// magic number of "llvc". This acounts for the +/-4 arithmetic in the code
// below.
int hdrSize;
if (willCompress) {
char* output = 0;
if (member.isBytecode()) {
data +=4;
fSize -= 4;
}
fSize = Compressor::compressToNewBuffer(data,fSize,output);
data = output;
if (member.isBytecode())
hdrSize = -fSize-4;
else
hdrSize = -fSize;
} else {
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().toString().data(),
member.getPath().toString().length());
}
// Make sure we write the compressed bytecode magic number if we should.
if (willCompress && member.isBytecode())
ARFile.write("llvc",4);
// 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;
// Free the compressed data, if necessary
if (willCompress) {
free((void*)data);
}
// Close the mapped file if it was opened
if (mFile != 0) {
mFile->close();
delete mFile;
}
}
// 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));
// Save the starting position of the symbol tables data content.
unsigned startpos = ARFile.tellp();
// 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());
}
// Now that we're done with the symbol table, get the ending file position
unsigned endpos = ARFile.tellp();
// 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.
void
Archive::writeToDisk(bool CreateSymbolTable, bool TruncateNames, bool Compress){
// 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.
assert(!(members.empty() && mapfile->size() > 8) &&
"Can't write an archive not opened for writing");
// Create a temporary file to store the archive in
sys::Path TmpArchive = archPath;
TmpArchive.createTemporaryFileOnDisk();
// Make sure the temporary gets removed if we crash
sys::RemoveFileOnSignal(TmpArchive);
// Ensure we can remove the temporary even in the face of an exception
try {
// 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() ) {
throw std::string("Error opening archive file: ") + archPath.toString();
}
// 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) {
writeMember(*I,ArchiveFile,CreateSymbolTable,TruncateNames,Compress);
}
// 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.
// Map in the archive we just wrote.
sys::MappedFile arch(TmpArchive);
const char* base = (const char*) arch.map();
// Open the final file to write and check it.
std::ofstream FinalFile(archPath.c_str(), io_mode);
if ( !FinalFile.is_open() || FinalFile.bad() ) {
throw std::string("Error opening archive file: ") + archPath.toString();
}
// 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) {
writeMember(*foreignST, FinalFile, false, false, false);
}
// 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.size()-sizeof(ARFILE_MAGIC)+1);
// Close up shop
FinalFile.close();
arch.close();
TmpArchive.eraseFromDisk();
} else {
// We don't have to insert the symbol table, so just renaming the temp
// file to the correct name will suffice.
TmpArchive.renamePathOnDisk(archPath);
}
} catch (...) {
// Make sure we clean up.
if (TmpArchive.exists())
TmpArchive.eraseFromDisk();
throw;
}
}