1 //===-- ArchiveWriter.cpp - Write LLVM archive files ----------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Reid Spencer and is distributed under the
6 // University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Builds up an LLVM archive file (.a) containing LLVM bytecode.
12 //===----------------------------------------------------------------------===//
14 #include "ArchiveInternals.h"
15 #include "llvm/Bytecode/Reader.h"
16 #include "llvm/Support/Compressor.h"
17 #include "llvm/System/Signals.h"
24 // Write an integer using variable bit rate encoding. This saves a few bytes
25 // per entry in the symbol table.
26 inline void writeInteger(unsigned num, std::ofstream& ARFile) {
28 if (num < 0x80) { // done?
29 ARFile << (unsigned char)num;
33 // Nope, we are bigger than a character, output the next 7 bits and set the
34 // high bit to say that there is more coming...
35 ARFile << (unsigned char)(0x80 | ((unsigned char)num & 0x7F));
36 num >>= 7; // Shift out 7 bits now...
40 // Compute how many bytes are taken by a given VBR encoded value. This is needed
41 // to pre-compute the size of the symbol table.
42 inline unsigned numVbrBytes(unsigned num) {
44 // Note that the following nested ifs are somewhat equivalent to a binary
45 // search. We split it in half by comparing against 2^14 first. This allows
46 // most reasonable values to be done in 2 comparisons instead of 1 for
47 // small ones and four for large ones. We expect this to access file offsets
48 // in the 2^10 to 2^24 range and symbol lengths in the 2^0 to 2^8 range,
49 // so this approach is reasonable.
60 return 5; // anything >= 2^28 takes 5 bytes
63 // Create an empty archive.
65 Archive::CreateEmpty(const sys::Path& FilePath ) {
66 Archive* result = new Archive(FilePath,false);
70 // Fill the ArchiveMemberHeader with the information from a member. If
71 // TruncateNames is true, names are flattened to 15 chars or less. The sz field
72 // is provided here instead of coming from the mbr because the member might be
73 // stored compressed and the compressed size is not the ArchiveMember's size.
74 // Furthermore compressed files have negative size fields to identify them as
77 Archive::fillHeader(const ArchiveMember &mbr, ArchiveMemberHeader& hdr,
78 int sz, bool TruncateNames) const {
80 // Set the permissions mode, uid and gid
83 sprintf(buffer, "%-8o", mbr.getMode());
84 memcpy(hdr.mode,buffer,8);
85 sprintf(buffer, "%-6u", mbr.getUser());
86 memcpy(hdr.uid,buffer,6);
87 sprintf(buffer, "%-6u", mbr.getGroup());
88 memcpy(hdr.gid,buffer,6);
90 // Set the last modification date
91 uint64_t secondsSinceEpoch = mbr.getModTime().toEpochTime();
92 sprintf(buffer,"%-12u", unsigned(secondsSinceEpoch));
93 memcpy(hdr.date,buffer,12);
95 // Get rid of trailing blanks in the name
96 std::string mbrPath = mbr.getPath().toString();
97 size_t mbrLen = mbrPath.length();
98 while (mbrLen > 0 && mbrPath[mbrLen-1] == ' ') {
99 mbrPath.erase(mbrLen-1,1);
103 // Set the name field in one of its various flavors.
104 bool writeLongName = false;
105 if (mbr.isStringTable()) {
106 memcpy(hdr.name,ARFILE_STRTAB_NAME,16);
107 } else if (mbr.isSVR4SymbolTable()) {
108 memcpy(hdr.name,ARFILE_SVR4_SYMTAB_NAME,16);
109 } else if (mbr.isBSD4SymbolTable()) {
110 memcpy(hdr.name,ARFILE_BSD4_SYMTAB_NAME,16);
111 } else if (mbr.isLLVMSymbolTable()) {
112 memcpy(hdr.name,ARFILE_LLVM_SYMTAB_NAME,16);
113 } else if (TruncateNames) {
114 const char* nm = mbrPath.c_str();
115 unsigned len = mbrPath.length();
116 size_t slashpos = mbrPath.rfind('/');
117 if (slashpos != std::string::npos) {
123 memcpy(hdr.name,nm,len);
125 } else if (mbrPath.length() < 16 && mbrPath.find('/') == std::string::npos) {
126 memcpy(hdr.name,mbrPath.c_str(),mbrPath.length());
127 hdr.name[mbrPath.length()] = '/';
129 std::string nm = "#1/";
130 nm += utostr(mbrPath.length());
131 memcpy(hdr.name,nm.data(),nm.length());
133 sz -= mbrPath.length();
135 sz += mbrPath.length();
136 writeLongName = true;
139 // Set the size field
142 sprintf(&buffer[1],"%-9u",(unsigned)-sz);
144 sprintf(buffer, "%-10u", (unsigned)sz);
146 memcpy(hdr.size,buffer,10);
148 return writeLongName;
151 // Insert a file into the archive before some other member. This also takes care
152 // of extracting the necessary flags and information from the file.
154 Archive::addFileBefore(const sys::Path& filePath, iterator where) {
155 assert(filePath.exists() && "Can't add a non-existent file");
157 ArchiveMember* mbr = new ArchiveMember(this);
160 mbr->path = filePath;
161 mbr->path.getStatusInfo(mbr->info);
164 bool hasSlash = filePath.toString().find('/') != std::string::npos;
166 flags |= ArchiveMember::HasPathFlag;
167 if (hasSlash || filePath.toString().length() > 15)
168 flags |= ArchiveMember::HasLongFilenameFlag;
170 mbr->path.getMagicNumber(magic,4);
171 switch (sys::IdentifyFileType(magic.c_str(),4)) {
172 case sys::BytecodeFileType:
173 flags |= ArchiveMember::BytecodeFlag;
175 case sys::CompressedBytecodeFileType:
176 flags |= ArchiveMember::CompressedBytecodeFlag;
182 members.insert(where,mbr);
185 // Write one member out to the file.
187 Archive::writeMember(
188 const ArchiveMember& member,
189 std::ofstream& ARFile,
190 bool CreateSymbolTable,
195 unsigned filepos = ARFile.tellp();
198 // Get the data and its size either from the
199 // member's in-memory data or directly from the file.
200 size_t fSize = member.getSize();
201 const char* data = (const char*)member.getData();
202 sys::MappedFile* mFile = 0;
204 mFile = new sys::MappedFile(member.getPath());
205 data = (const char*) mFile->map();
206 fSize = mFile->size();
209 // Now that we have the data in memory, update the
210 // symbol table if its a bytecode file.
211 if (CreateSymbolTable &&
212 (member.isBytecode() || member.isCompressedBytecode())) {
213 std::vector<std::string> symbols;
214 std::string FullMemberName = archPath.toString() + "(" +
215 member.getPath().toString()
217 ModuleProvider* MP = GetBytecodeSymbols(
218 (const unsigned char*)data,fSize,FullMemberName, symbols);
220 // If the bytecode parsed successfully
222 for (std::vector<std::string>::iterator SI = symbols.begin(),
223 SE = symbols.end(); SI != SE; ++SI) {
225 std::pair<SymTabType::iterator,bool> Res =
226 symTab.insert(std::make_pair(*SI,filepos));
229 symTabSize += SI->length() +
230 numVbrBytes(SI->length()) +
231 numVbrBytes(filepos);
234 // We don't need this module any more.
237 throw std::string("Can't parse bytecode member: ") +
238 member.getPath().toString();
242 // Determine if we actually should compress this member
245 !member.isCompressed() &&
246 !member.isCompressedBytecode() &&
247 !member.isLLVMSymbolTable() &&
248 !member.isSVR4SymbolTable() &&
249 !member.isBSD4SymbolTable());
251 // Perform the compression. Note that if the file is uncompressed bytecode
252 // then we turn the file into compressed bytecode rather than treating it as
253 // compressed data. This is necessary since it allows us to determine that the
254 // file contains bytecode instead of looking like a regular compressed data
255 // member. A compressed bytecode file has its content compressed but has a
256 // magic number of "llvc". This acounts for the +/-4 arithmetic in the code
261 if (member.isBytecode()) {
265 fSize = Compressor::compressToNewBuffer(data,fSize,output);
267 if (member.isBytecode())
275 // Compute the fields of the header
276 ArchiveMemberHeader Hdr;
277 bool writeLongName = fillHeader(member,Hdr,hdrSize,TruncateNames);
279 // Write header to archive file
280 ARFile.write((char*)&Hdr, sizeof(Hdr));
282 // Write the long filename if its long
284 ARFile.write(member.getPath().toString().data(),
285 member.getPath().toString().length());
288 // Make sure we write the compressed bytecode magic number if we should.
289 if (willCompress && member.isBytecode())
290 ARFile.write("llvc",4);
292 // Write the (possibly compressed) member's content to the file.
293 ARFile.write(data,fSize);
295 // Make sure the member is an even length
296 if ((ARFile.tellp() & 1) == 1)
297 ARFile << ARFILE_PAD;
299 // Free the compressed data, if necessary
304 // Close the mapped file if it was opened
311 // Write out the LLVM symbol table as an archive member to the file.
313 Archive::writeSymbolTable(std::ofstream& ARFile) {
315 // Construct the symbol table's header
316 ArchiveMemberHeader Hdr;
318 memcpy(Hdr.name,ARFILE_LLVM_SYMTAB_NAME,16);
319 uint64_t secondsSinceEpoch = sys::TimeValue::now().toEpochTime();
321 sprintf(buffer,"%-12u", unsigned(secondsSinceEpoch));
322 memcpy(Hdr.date,buffer,12);
323 sprintf(buffer,"%-10u",symTabSize);
324 memcpy(Hdr.size,buffer,10);
327 ARFile.write((char*)&Hdr, sizeof(Hdr));
329 // Save the starting position of the symbol tables data content.
330 unsigned startpos = ARFile.tellp();
332 // Write out the symbols sequentially
333 for ( Archive::SymTabType::iterator I = symTab.begin(), E = symTab.end();
336 // Write out the file index
337 writeInteger(I->second, ARFile);
338 // Write out the length of the symbol
339 writeInteger(I->first.length(), ARFile);
340 // Write out the symbol
341 ARFile.write(I->first.data(), I->first.length());
344 // Now that we're done with the symbol table, get the ending file position
345 unsigned endpos = ARFile.tellp();
347 // Make sure that the amount we wrote is what we pre-computed. This is
348 // critical for file integrity purposes.
349 assert(endpos - startpos == symTabSize && "Invalid symTabSize computation");
351 // Make sure the symbol table is even sized
352 if (symTabSize % 2 != 0 )
353 ARFile << ARFILE_PAD;
356 // Write the entire archive to the file specified when the archive was created.
357 // This writes to a temporary file first. Options are for creating a symbol
358 // table, flattening the file names (no directories, 15 chars max) and
359 // compressing each archive member.
361 Archive::writeToDisk(bool CreateSymbolTable, bool TruncateNames, bool Compress){
363 // Make sure they haven't opened up the file, not loaded it,
364 // but are now trying to write it which would wipe out the file.
365 assert(!(members.empty() && mapfile->size() > 8) &&
366 "Can't write an archive not opened for writing");
368 // Create a temporary file to store the archive in
369 sys::Path TmpArchive = archPath;
370 TmpArchive.createTemporaryFile();
372 // Make sure the temporary gets removed if we crash
373 sys::RemoveFileOnSignal(TmpArchive);
375 // Ensure we can remove the temporary even in the face of an exception
377 // Create archive file for output.
378 std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
380 std::ofstream ArchiveFile(TmpArchive.c_str(), io_mode);
382 // Check for errors opening or creating archive file.
383 if ( !ArchiveFile.is_open() || ArchiveFile.bad() ) {
384 throw std::string("Error opening archive file: ") + archPath.toString();
387 // If we're creating a symbol table, reset it now
388 if (CreateSymbolTable) {
393 // Write magic string to archive.
394 ArchiveFile << ARFILE_MAGIC;
396 // Loop over all member files, and write them out. Note that this also
397 // builds the symbol table, symTab.
398 for ( MembersList::iterator I = begin(), E = end(); I != E; ++I) {
399 writeMember(*I,ArchiveFile,CreateSymbolTable,TruncateNames,Compress);
402 // Close archive file.
405 // Write the symbol table
406 if (CreateSymbolTable) {
407 // At this point we have written a file that is a legal archive but it
408 // doesn't have a symbol table in it. To aid in faster reading and to
409 // ensure compatibility with other archivers we need to put the symbol
410 // table first in the file. Unfortunately, this means mapping the file
411 // we just wrote back in and copying it to the destination file.
413 // Map in the archive we just wrote.
414 sys::MappedFile arch(TmpArchive);
415 const char* base = (const char*) arch.map();
417 // Open the final file to write and check it.
418 std::ofstream FinalFile(archPath.c_str(), io_mode);
419 if ( !FinalFile.is_open() || FinalFile.bad() ) {
420 throw std::string("Error opening archive file: ") + archPath.toString();
423 // Write the file magic number
424 FinalFile << ARFILE_MAGIC;
426 // If there is a foreign symbol table, put it into the file now. Most
427 // ar(1) implementations require the symbol table to be first but llvm-ar
428 // can deal with it being after a foreign symbol table. This ensures
429 // compatibility with other ar(1) implementations as well as allowing the
430 // archive to store both native .o and LLVM .bc files, both indexed.
432 writeMember(*foreignST, FinalFile, false, false, false);
435 // Put out the LLVM symbol table now.
436 writeSymbolTable(FinalFile);
438 // Copy the temporary file contents being sure to skip the file's magic
440 FinalFile.write(base + sizeof(ARFILE_MAGIC)-1,
441 arch.size()-sizeof(ARFILE_MAGIC)+1);
446 TmpArchive.destroyFile();
449 // We don't have to insert the symbol table, so just renaming the temp
450 // file to the correct name will suffice.
451 TmpArchive.renameFile(archPath);
454 // Make sure we clean up.
455 if (TmpArchive.exists())
456 TmpArchive.destroyFile();