1 //===-- ArchiveWriter.cpp - Write LLVM archive files ----------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Builds up an LLVM archive file (.a) containing LLVM bitcode.
12 //===----------------------------------------------------------------------===//
14 #include "ArchiveInternals.h"
15 #include "llvm/Module.h"
16 #include "llvm/ADT/OwningPtr.h"
17 #include "llvm/Bitcode/ReaderWriter.h"
18 #include "llvm/Support/MemoryBuffer.h"
19 #include "llvm/System/Process.h"
20 #include "llvm/System/Signals.h"
26 // Write an integer using variable bit rate encoding. This saves a few bytes
27 // per entry in the symbol table.
28 static inline void writeInteger(unsigned num, std::ofstream& ARFile) {
30 if (num < 0x80) { // done?
31 ARFile << (unsigned char)num;
35 // Nope, we are bigger than a character, output the next 7 bits and set the
36 // high bit to say that there is more coming...
37 ARFile << (unsigned char)(0x80 | ((unsigned char)num & 0x7F));
38 num >>= 7; // Shift out 7 bits now...
42 // Compute how many bytes are taken by a given VBR encoded value. This is needed
43 // to pre-compute the size of the symbol table.
44 static inline unsigned numVbrBytes(unsigned num) {
46 // Note that the following nested ifs are somewhat equivalent to a binary
47 // search. We split it in half by comparing against 2^14 first. This allows
48 // most reasonable values to be done in 2 comparisons instead of 1 for
49 // small ones and four for large ones. We expect this to access file offsets
50 // in the 2^10 to 2^24 range and symbol lengths in the 2^0 to 2^8 range,
51 // so this approach is reasonable.
63 return 5; // anything >= 2^28 takes 5 bytes
66 // Create an empty archive.
67 Archive* Archive::CreateEmpty(const sys::Path& FilePath, LLVMContext& C) {
68 Archive* result = new Archive(FilePath, C);
72 // Fill the ArchiveMemberHeader with the information from a member. If
73 // TruncateNames is true, names are flattened to 15 chars or less. The sz field
74 // is provided here instead of coming from the mbr because the member might be
75 // stored compressed and the compressed size is not the ArchiveMember's size.
76 // Furthermore compressed files have negative size fields to identify them as
79 Archive::fillHeader(const ArchiveMember &mbr, ArchiveMemberHeader& hdr,
80 int sz, bool TruncateNames) const {
82 // Set the permissions mode, uid and gid
85 sprintf(buffer, "%-8o", mbr.getMode());
86 memcpy(hdr.mode,buffer,8);
87 sprintf(buffer, "%-6u", mbr.getUser());
88 memcpy(hdr.uid,buffer,6);
89 sprintf(buffer, "%-6u", mbr.getGroup());
90 memcpy(hdr.gid,buffer,6);
92 // Set the last modification date
93 uint64_t secondsSinceEpoch = mbr.getModTime().toEpochTime();
94 sprintf(buffer,"%-12u", unsigned(secondsSinceEpoch));
95 memcpy(hdr.date,buffer,12);
97 // Get rid of trailing blanks in the name
98 std::string mbrPath = mbr.getPath().str();
99 size_t mbrLen = mbrPath.length();
100 while (mbrLen > 0 && mbrPath[mbrLen-1] == ' ') {
101 mbrPath.erase(mbrLen-1,1);
105 // Set the name field in one of its various flavors.
106 bool writeLongName = false;
107 if (mbr.isStringTable()) {
108 memcpy(hdr.name,ARFILE_STRTAB_NAME,16);
109 } else if (mbr.isSVR4SymbolTable()) {
110 memcpy(hdr.name,ARFILE_SVR4_SYMTAB_NAME,16);
111 } else if (mbr.isBSD4SymbolTable()) {
112 memcpy(hdr.name,ARFILE_BSD4_SYMTAB_NAME,16);
113 } else if (mbr.isLLVMSymbolTable()) {
114 memcpy(hdr.name,ARFILE_LLVM_SYMTAB_NAME,16);
115 } else if (TruncateNames) {
116 const char* nm = mbrPath.c_str();
117 unsigned len = mbrPath.length();
118 size_t slashpos = mbrPath.rfind('/');
119 if (slashpos != std::string::npos) {
125 memcpy(hdr.name,nm,len);
127 } else if (mbrPath.length() < 16 && mbrPath.find('/') == std::string::npos) {
128 memcpy(hdr.name,mbrPath.c_str(),mbrPath.length());
129 hdr.name[mbrPath.length()] = '/';
131 std::string nm = "#1/";
132 nm += utostr(mbrPath.length());
133 memcpy(hdr.name,nm.data(),nm.length());
135 sz -= mbrPath.length();
137 sz += mbrPath.length();
138 writeLongName = true;
141 // Set the size field
144 sprintf(&buffer[1],"%-9u",(unsigned)-sz);
146 sprintf(buffer, "%-10u", (unsigned)sz);
148 memcpy(hdr.size,buffer,10);
150 return writeLongName;
153 // Insert a file into the archive before some other member. This also takes care
154 // of extracting the necessary flags and information from the file.
156 Archive::addFileBefore(const sys::Path& filePath, iterator where,
157 std::string* ErrMsg) {
158 if (!filePath.exists()) {
160 *ErrMsg = "Can not add a non-existent file to archive";
164 ArchiveMember* mbr = new ArchiveMember(this);
167 mbr->path = filePath;
168 const sys::FileStatus *FSInfo = mbr->path.getFileStatus(false, ErrMsg);
176 bool hasSlash = filePath.str().find('/') != std::string::npos;
178 flags |= ArchiveMember::HasPathFlag;
179 if (hasSlash || filePath.str().length() > 15)
180 flags |= ArchiveMember::HasLongFilenameFlag;
182 mbr->path.getMagicNumber(magic,4);
183 switch (sys::IdentifyFileType(magic.c_str(),4)) {
184 case sys::Bitcode_FileType:
185 flags |= ArchiveMember::BitcodeFlag;
191 members.insert(where,mbr);
195 // Write one member out to the file.
197 Archive::writeMember(
198 const ArchiveMember& member,
199 std::ofstream& ARFile,
200 bool CreateSymbolTable,
206 unsigned filepos = ARFile.tellp();
209 // Get the data and its size either from the
210 // member's in-memory data or directly from the file.
211 size_t fSize = member.getSize();
212 const char *data = (const char*)member.getData();
213 MemoryBuffer *mFile = 0;
215 mFile = MemoryBuffer::getFile(member.getPath().c_str(), ErrMsg);
218 data = mFile->getBufferStart();
219 fSize = mFile->getBufferSize();
222 // Now that we have the data in memory, update the
223 // symbol table if it's a bitcode file.
224 if (CreateSymbolTable && member.isBitcode()) {
225 std::vector<std::string> symbols;
226 std::string FullMemberName = archPath.str() + "(" + member.getPath().str()
229 GetBitcodeSymbols(data, fSize, FullMemberName, Context, symbols, ErrMsg);
231 // If the bitcode parsed successfully
233 for (std::vector<std::string>::iterator SI = symbols.begin(),
234 SE = symbols.end(); SI != SE; ++SI) {
236 std::pair<SymTabType::iterator,bool> Res =
237 symTab.insert(std::make_pair(*SI,filepos));
240 symTabSize += SI->length() +
241 numVbrBytes(SI->length()) +
242 numVbrBytes(filepos);
245 // We don't need this module any more.
250 *ErrMsg = "Can't parse bitcode member: " + member.getPath().str()
258 // Compute the fields of the header
259 ArchiveMemberHeader Hdr;
260 bool writeLongName = fillHeader(member,Hdr,hdrSize,TruncateNames);
262 // Write header to archive file
263 ARFile.write((char*)&Hdr, sizeof(Hdr));
265 // Write the long filename if its long
267 ARFile.write(member.getPath().str().data(),
268 member.getPath().str().length());
271 // Write the (possibly compressed) member's content to the file.
272 ARFile.write(data,fSize);
274 // Make sure the member is an even length
275 if ((ARFile.tellp() & 1) == 1)
276 ARFile << ARFILE_PAD;
278 // Close the mapped file if it was opened
283 // Write out the LLVM symbol table as an archive member to the file.
285 Archive::writeSymbolTable(std::ofstream& ARFile) {
287 // Construct the symbol table's header
288 ArchiveMemberHeader Hdr;
290 memcpy(Hdr.name,ARFILE_LLVM_SYMTAB_NAME,16);
291 uint64_t secondsSinceEpoch = sys::TimeValue::now().toEpochTime();
293 sprintf(buffer, "%-8o", 0644);
294 memcpy(Hdr.mode,buffer,8);
295 sprintf(buffer, "%-6u", sys::Process::GetCurrentUserId());
296 memcpy(Hdr.uid,buffer,6);
297 sprintf(buffer, "%-6u", sys::Process::GetCurrentGroupId());
298 memcpy(Hdr.gid,buffer,6);
299 sprintf(buffer,"%-12u", unsigned(secondsSinceEpoch));
300 memcpy(Hdr.date,buffer,12);
301 sprintf(buffer,"%-10u",symTabSize);
302 memcpy(Hdr.size,buffer,10);
305 ARFile.write((char*)&Hdr, sizeof(Hdr));
308 // Save the starting position of the symbol tables data content.
309 unsigned startpos = ARFile.tellp();
312 // Write out the symbols sequentially
313 for ( Archive::SymTabType::iterator I = symTab.begin(), E = symTab.end();
316 // Write out the file index
317 writeInteger(I->second, ARFile);
318 // Write out the length of the symbol
319 writeInteger(I->first.length(), ARFile);
320 // Write out the symbol
321 ARFile.write(I->first.data(), I->first.length());
325 // Now that we're done with the symbol table, get the ending file position
326 unsigned endpos = ARFile.tellp();
329 // Make sure that the amount we wrote is what we pre-computed. This is
330 // critical for file integrity purposes.
331 assert(endpos - startpos == symTabSize && "Invalid symTabSize computation");
333 // Make sure the symbol table is even sized
334 if (symTabSize % 2 != 0 )
335 ARFile << ARFILE_PAD;
338 // Write the entire archive to the file specified when the archive was created.
339 // This writes to a temporary file first. Options are for creating a symbol
340 // table, flattening the file names (no directories, 15 chars max) and
341 // compressing each archive member.
343 Archive::writeToDisk(bool CreateSymbolTable, bool TruncateNames, bool Compress,
346 // Make sure they haven't opened up the file, not loaded it,
347 // but are now trying to write it which would wipe out the file.
348 if (members.empty() && mapfile && mapfile->getBufferSize() > 8) {
350 *ErrMsg = "Can't write an archive not opened for writing";
354 // Create a temporary file to store the archive in
355 sys::Path TmpArchive = archPath;
356 if (TmpArchive.createTemporaryFileOnDisk(ErrMsg))
359 // Make sure the temporary gets removed if we crash
360 sys::RemoveFileOnSignal(TmpArchive);
362 // Create archive file for output.
363 std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
365 std::ofstream ArchiveFile(TmpArchive.c_str(), io_mode);
367 // Check for errors opening or creating archive file.
368 if (!ArchiveFile.is_open() || ArchiveFile.bad()) {
369 if (TmpArchive.exists())
370 TmpArchive.eraseFromDisk();
372 *ErrMsg = "Error opening archive file: " + archPath.str();
376 // If we're creating a symbol table, reset it now
377 if (CreateSymbolTable) {
382 // Write magic string to archive.
383 ArchiveFile << ARFILE_MAGIC;
385 // Loop over all member files, and write them out. Note that this also
386 // builds the symbol table, symTab.
387 for (MembersList::iterator I = begin(), E = end(); I != E; ++I) {
388 if (writeMember(*I, ArchiveFile, CreateSymbolTable,
389 TruncateNames, Compress, ErrMsg)) {
390 if (TmpArchive.exists())
391 TmpArchive.eraseFromDisk();
397 // Close archive file.
400 // Write the symbol table
401 if (CreateSymbolTable) {
402 // At this point we have written a file that is a legal archive but it
403 // doesn't have a symbol table in it. To aid in faster reading and to
404 // ensure compatibility with other archivers we need to put the symbol
405 // table first in the file. Unfortunately, this means mapping the file
406 // we just wrote back in and copying it to the destination file.
407 sys::Path FinalFilePath = archPath;
409 // Map in the archive we just wrote.
411 OwningPtr<MemoryBuffer> arch(MemoryBuffer::getFile(TmpArchive.c_str()));
412 if (arch == 0) return true;
413 const char* base = arch->getBufferStart();
415 // Open another temporary file in order to avoid invalidating the
417 if (FinalFilePath.createTemporaryFileOnDisk(ErrMsg))
419 sys::RemoveFileOnSignal(FinalFilePath);
421 std::ofstream FinalFile(FinalFilePath.c_str(), io_mode);
422 if (!FinalFile.is_open() || FinalFile.bad()) {
423 if (TmpArchive.exists())
424 TmpArchive.eraseFromDisk();
426 *ErrMsg = "Error opening archive file: " + FinalFilePath.str();
430 // Write the file magic number
431 FinalFile << ARFILE_MAGIC;
433 // If there is a foreign symbol table, put it into the file now. Most
434 // ar(1) implementations require the symbol table to be first but llvm-ar
435 // can deal with it being after a foreign symbol table. This ensures
436 // compatibility with other ar(1) implementations as well as allowing the
437 // archive to store both native .o and LLVM .bc files, both indexed.
439 if (writeMember(*foreignST, FinalFile, false, false, false, ErrMsg)) {
441 if (TmpArchive.exists())
442 TmpArchive.eraseFromDisk();
447 // Put out the LLVM symbol table now.
448 writeSymbolTable(FinalFile);
450 // Copy the temporary file contents being sure to skip the file's magic
452 FinalFile.write(base + sizeof(ARFILE_MAGIC)-1,
453 arch->getBufferSize()-sizeof(ARFILE_MAGIC)+1);
459 // Move the final file over top of TmpArchive
460 if (FinalFilePath.renamePathOnDisk(TmpArchive, ErrMsg))
464 // Before we replace the actual archive, we need to forget all the
465 // members, since they point to data in that old archive. We need to do
466 // this because we cannot replace an open file on Windows.
469 if (TmpArchive.renamePathOnDisk(archPath, ErrMsg))
472 // Set correct read and write permissions after temporary file is moved
473 // to final destination path.
474 if (archPath.makeReadableOnDisk(ErrMsg))
476 if (archPath.makeWriteableOnDisk(ErrMsg))