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 //===----------------------------------------------------------------------===//
15 #include "ArchiveInternals.h"
16 #include "llvm/ADT/OwningPtr.h"
17 #include "llvm/Bitcode/ReaderWriter.h"
18 #include "llvm/IR/Module.h"
19 #include "llvm/Support/FileSystem.h"
20 #include "llvm/Support/MemoryBuffer.h"
21 #include "llvm/Support/Process.h"
22 #include "llvm/Support/Signals.h"
23 #include "llvm/Support/system_error.h"
29 // Write an integer using variable bit rate encoding. This saves a few bytes
30 // per entry in the symbol table.
31 static inline void writeInteger(unsigned num, std::ofstream& ARFile) {
33 if (num < 0x80) { // done?
34 ARFile << (unsigned char)num;
38 // Nope, we are bigger than a character, output the next 7 bits and set the
39 // high bit to say that there is more coming...
40 ARFile << (unsigned char)(0x80 | ((unsigned char)num & 0x7F));
41 num >>= 7; // Shift out 7 bits now...
45 // Compute how many bytes are taken by a given VBR encoded value. This is needed
46 // to pre-compute the size of the symbol table.
47 static inline unsigned numVbrBytes(unsigned num) {
49 // Note that the following nested ifs are somewhat equivalent to a binary
50 // search. We split it in half by comparing against 2^14 first. This allows
51 // most reasonable values to be done in 2 comparisons instead of 1 for
52 // small ones and four for large ones. We expect this to access file offsets
53 // in the 2^10 to 2^24 range and symbol lengths in the 2^0 to 2^8 range,
54 // so this approach is reasonable.
66 return 5; // anything >= 2^28 takes 5 bytes
69 // Create an empty archive.
70 Archive* Archive::CreateEmpty(const sys::Path& FilePath, LLVMContext& C) {
71 Archive* result = new Archive(FilePath, C);
75 // Fill the ArchiveMemberHeader with the information from a member. If
76 // TruncateNames is true, names are flattened to 15 chars or less. The sz field
77 // is provided here instead of coming from the mbr because the member might be
78 // stored compressed and the compressed size is not the ArchiveMember's size.
79 // Furthermore compressed files have negative size fields to identify them as
82 Archive::fillHeader(const ArchiveMember &mbr, ArchiveMemberHeader& hdr,
83 int sz, bool TruncateNames) const {
85 // Set the permissions mode, uid and gid
88 sprintf(buffer, "%-8o", mbr.getMode());
89 memcpy(hdr.mode,buffer,8);
90 sprintf(buffer, "%-6u", mbr.getUser());
91 memcpy(hdr.uid,buffer,6);
92 sprintf(buffer, "%-6u", mbr.getGroup());
93 memcpy(hdr.gid,buffer,6);
95 // Set the last modification date
96 uint64_t secondsSinceEpoch = mbr.getModTime().toEpochTime();
97 sprintf(buffer,"%-12u", unsigned(secondsSinceEpoch));
98 memcpy(hdr.date,buffer,12);
100 // Get rid of trailing blanks in the name
101 std::string mbrPath = mbr.getPath().str();
102 size_t mbrLen = mbrPath.length();
103 while (mbrLen > 0 && mbrPath[mbrLen-1] == ' ') {
104 mbrPath.erase(mbrLen-1,1);
108 // Set the name field in one of its various flavors.
109 bool writeLongName = false;
110 if (mbr.isStringTable()) {
111 memcpy(hdr.name,ARFILE_STRTAB_NAME,16);
112 } else if (mbr.isSVR4SymbolTable()) {
113 memcpy(hdr.name,ARFILE_SVR4_SYMTAB_NAME,16);
114 } else if (mbr.isBSD4SymbolTable()) {
115 memcpy(hdr.name,ARFILE_BSD4_SYMTAB_NAME,16);
116 } else if (TruncateNames) {
117 const char* nm = mbrPath.c_str();
118 unsigned len = mbrPath.length();
119 size_t slashpos = mbrPath.rfind('/');
120 if (slashpos != std::string::npos) {
126 memcpy(hdr.name,nm,len);
128 } else if (mbrPath.length() < 16 && mbrPath.find('/') == std::string::npos) {
129 memcpy(hdr.name,mbrPath.c_str(),mbrPath.length());
130 hdr.name[mbrPath.length()] = '/';
132 std::string nm = "#1/";
133 nm += utostr(mbrPath.length());
134 memcpy(hdr.name,nm.data(),nm.length());
136 sz -= mbrPath.length();
138 sz += mbrPath.length();
139 writeLongName = true;
142 // Set the size field
145 sprintf(&buffer[1],"%-9u",(unsigned)-sz);
147 sprintf(buffer, "%-10u", (unsigned)sz);
149 memcpy(hdr.size,buffer,10);
151 return writeLongName;
154 // Insert a file into the archive before some other member. This also takes care
155 // of extracting the necessary flags and information from the file.
157 Archive::addFileBefore(const sys::Path& filePath, iterator where,
158 std::string* ErrMsg) {
160 if (sys::fs::exists(filePath.str(), Exists) || !Exists) {
162 *ErrMsg = "Can not add a non-existent file to archive";
166 ArchiveMember* mbr = new ArchiveMember(this);
169 mbr->path = filePath.str();
170 sys::PathWithStatus PWS(mbr->path);
171 const sys::FileStatus *FSInfo = PWS.getFileStatus(false, ErrMsg);
179 bool hasSlash = filePath.str().find('/') != std::string::npos;
181 flags |= ArchiveMember::HasPathFlag;
182 if (hasSlash || filePath.str().length() > 15)
183 flags |= ArchiveMember::HasLongFilenameFlag;
185 sys::fs::file_magic type;
186 if (sys::fs::identify_magic(mbr->path, type))
187 type = sys::fs::file_magic::unknown;
189 case sys::fs::file_magic::bitcode:
190 flags |= ArchiveMember::BitcodeFlag;
196 members.insert(where,mbr);
200 // Write one member out to the file.
202 Archive::writeMember(
203 const ArchiveMember& member,
204 std::ofstream& ARFile,
205 bool CreateSymbolTable,
210 unsigned filepos = ARFile.tellp();
213 // Get the data and its size either from the
214 // member's in-memory data or directly from the file.
215 size_t fSize = member.getSize();
216 const char *data = (const char*)member.getData();
217 MemoryBuffer *mFile = 0;
219 OwningPtr<MemoryBuffer> File;
220 if (error_code ec = MemoryBuffer::getFile(member.getPath(), File)) {
222 *ErrMsg = ec.message();
226 data = mFile->getBufferStart();
227 fSize = mFile->getBufferSize();
230 // Now that we have the data in memory, update the
231 // symbol table if it's a bitcode file.
232 if (CreateSymbolTable && member.isBitcode()) {
233 std::vector<std::string> symbols;
234 std::string FullMemberName = archPath.str() + "(" + member.getPath().str()
237 GetBitcodeSymbols(data, fSize, FullMemberName, Context, symbols, ErrMsg);
239 // If the bitcode parsed successfully
241 for (std::vector<std::string>::iterator SI = symbols.begin(),
242 SE = symbols.end(); SI != SE; ++SI) {
244 std::pair<SymTabType::iterator,bool> Res =
245 symTab.insert(std::make_pair(*SI,filepos));
248 symTabSize += SI->length() +
249 numVbrBytes(SI->length()) +
250 numVbrBytes(filepos);
253 // We don't need this module any more.
258 *ErrMsg = "Can't parse bitcode member: " + member.getPath().str()
266 // Compute the fields of the header
267 ArchiveMemberHeader Hdr;
268 bool writeLongName = fillHeader(member,Hdr,hdrSize,TruncateNames);
270 // Write header to archive file
271 ARFile.write((char*)&Hdr, sizeof(Hdr));
273 // Write the long filename if its long
275 ARFile.write(member.getPath().str().data(),
276 member.getPath().str().length());
279 // Write the (possibly compressed) member's content to the file.
280 ARFile.write(data,fSize);
282 // Make sure the member is an even length
283 if ((ARFile.tellp() & 1) == 1)
284 ARFile << ARFILE_PAD;
286 // Close the mapped file if it was opened
291 // Write the entire archive to the file specified when the archive was created.
292 // This writes to a temporary file first. Options are for creating a symbol
293 // table, flattening the file names (no directories, 15 chars max) and
294 // compressing each archive member.
296 Archive::writeToDisk(bool CreateSymbolTable, bool TruncateNames,
299 // Make sure they haven't opened up the file, not loaded it,
300 // but are now trying to write it which would wipe out the file.
301 if (members.empty() && mapfile && mapfile->getBufferSize() > 8) {
303 *ErrMsg = "Can't write an archive not opened for writing";
307 // Create a temporary file to store the archive in
308 sys::Path TmpArchive = archPath;
309 if (TmpArchive.createTemporaryFileOnDisk(ErrMsg))
312 // Make sure the temporary gets removed if we crash
313 sys::RemoveFileOnSignal(TmpArchive.str());
315 // Create archive file for output.
316 std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
318 std::ofstream ArchiveFile(TmpArchive.c_str(), io_mode);
320 // Check for errors opening or creating archive file.
321 if (!ArchiveFile.is_open() || ArchiveFile.bad()) {
322 TmpArchive.eraseFromDisk();
324 *ErrMsg = "Error opening archive file: " + archPath.str();
328 // If we're creating a symbol table, reset it now
329 if (CreateSymbolTable) {
334 // Write magic string to archive.
335 ArchiveFile << ARFILE_MAGIC;
337 // Loop over all member files, and write them out. Note that this also
338 // builds the symbol table, symTab.
339 for (MembersList::iterator I = begin(), E = end(); I != E; ++I) {
340 if (writeMember(*I, ArchiveFile, CreateSymbolTable,
341 TruncateNames, ErrMsg)) {
342 TmpArchive.eraseFromDisk();
348 // Close archive file.
351 // Write the symbol table
352 if (CreateSymbolTable) {
353 // At this point we have written a file that is a legal archive but it
354 // doesn't have a symbol table in it. To aid in faster reading and to
355 // ensure compatibility with other archivers we need to put the symbol
356 // table first in the file. Unfortunately, this means mapping the file
357 // we just wrote back in and copying it to the destination file.
358 sys::Path FinalFilePath = archPath;
360 // Map in the archive we just wrote.
362 OwningPtr<MemoryBuffer> arch;
363 if (error_code ec = MemoryBuffer::getFile(TmpArchive.c_str(), arch)) {
365 *ErrMsg = ec.message();
368 const char* base = arch->getBufferStart();
370 // Open another temporary file in order to avoid invalidating the
372 if (FinalFilePath.createTemporaryFileOnDisk(ErrMsg))
374 sys::RemoveFileOnSignal(FinalFilePath.str());
376 std::ofstream FinalFile(FinalFilePath.c_str(), io_mode);
377 if (!FinalFile.is_open() || FinalFile.bad()) {
378 TmpArchive.eraseFromDisk();
380 *ErrMsg = "Error opening archive file: " + FinalFilePath.str();
384 // Write the file magic number
385 FinalFile << ARFILE_MAGIC;
387 // If there is a foreign symbol table, put it into the file now. Most
388 // ar(1) implementations require the symbol table to be first but llvm-ar
389 // can deal with it being after a foreign symbol table. This ensures
390 // compatibility with other ar(1) implementations as well as allowing the
391 // archive to store both native .o and LLVM .bc files, both indexed.
393 if (writeMember(*foreignST, FinalFile, false, false, ErrMsg)) {
395 TmpArchive.eraseFromDisk();
400 // Copy the temporary file contents being sure to skip the file's magic
402 FinalFile.write(base + sizeof(ARFILE_MAGIC)-1,
403 arch->getBufferSize()-sizeof(ARFILE_MAGIC)+1);
409 // Move the final file over top of TmpArchive
410 if (FinalFilePath.renamePathOnDisk(TmpArchive, ErrMsg))
414 // Before we replace the actual archive, we need to forget all the
415 // members, since they point to data in that old archive. We need to do
416 // this because we cannot replace an open file on Windows.
419 if (TmpArchive.renamePathOnDisk(archPath, ErrMsg))
422 // Set correct read and write permissions after temporary file is moved
423 // to final destination path.
424 if (archPath.makeReadableOnDisk(ErrMsg))
426 if (archPath.makeWriteableOnDisk(ErrMsg))