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(StringRef 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.
156 bool Archive::addFileBefore(StringRef filePath, iterator where,
157 std::string *ErrMsg) {
159 if (sys::fs::exists(filePath.str(), Exists) || !Exists) {
161 *ErrMsg = "Can not add a non-existent file to archive";
165 ArchiveMember* mbr = new ArchiveMember(this);
168 mbr->path = filePath.str();
169 sys::PathWithStatus PWS(mbr->path);
170 const sys::FileStatus *FSInfo = PWS.getFileStatus(false, ErrMsg);
178 bool hasSlash = filePath.str().find('/') != std::string::npos;
180 flags |= ArchiveMember::HasPathFlag;
181 if (hasSlash || filePath.str().length() > 15)
182 flags |= ArchiveMember::HasLongFilenameFlag;
184 sys::fs::file_magic type;
185 if (sys::fs::identify_magic(mbr->path, type))
186 type = sys::fs::file_magic::unknown;
188 case sys::fs::file_magic::bitcode:
189 flags |= ArchiveMember::BitcodeFlag;
195 members.insert(where,mbr);
199 // Write one member out to the file.
201 Archive::writeMember(
202 const ArchiveMember& member,
203 std::ofstream& ARFile,
204 bool CreateSymbolTable,
209 unsigned filepos = ARFile.tellp();
212 // Get the data and its size either from the
213 // member's in-memory data or directly from the file.
214 size_t fSize = member.getSize();
215 const char *data = (const char*)member.getData();
216 MemoryBuffer *mFile = 0;
218 OwningPtr<MemoryBuffer> File;
219 if (error_code ec = MemoryBuffer::getFile(member.getPath(), File)) {
221 *ErrMsg = ec.message();
225 data = mFile->getBufferStart();
226 fSize = mFile->getBufferSize();
229 // Now that we have the data in memory, update the
230 // symbol table if it's a bitcode file.
231 if (CreateSymbolTable && member.isBitcode()) {
232 std::vector<std::string> symbols;
233 std::string FullMemberName =
234 (archPath + "(" + member.getPath() + ")").str();
236 GetBitcodeSymbols(data, fSize, FullMemberName, Context, symbols, ErrMsg);
238 // If the bitcode parsed successfully
240 for (std::vector<std::string>::iterator SI = symbols.begin(),
241 SE = symbols.end(); SI != SE; ++SI) {
243 std::pair<SymTabType::iterator,bool> Res =
244 symTab.insert(std::make_pair(*SI,filepos));
247 symTabSize += SI->length() +
248 numVbrBytes(SI->length()) +
249 numVbrBytes(filepos);
252 // We don't need this module any more.
257 *ErrMsg = "Can't parse bitcode member: " + member.getPath().str()
265 // Compute the fields of the header
266 ArchiveMemberHeader Hdr;
267 bool writeLongName = fillHeader(member,Hdr,hdrSize,TruncateNames);
269 // Write header to archive file
270 ARFile.write((char*)&Hdr, sizeof(Hdr));
272 // Write the long filename if its long
274 ARFile.write(member.getPath().str().data(),
275 member.getPath().str().length());
278 // Write the (possibly compressed) member's content to the file.
279 ARFile.write(data,fSize);
281 // Make sure the member is an even length
282 if ((ARFile.tellp() & 1) == 1)
283 ARFile << ARFILE_PAD;
285 // Close the mapped file if it was opened
290 // Write the entire archive to the file specified when the archive was created.
291 // This writes to a temporary file first. Options are for creating a symbol
292 // table, flattening the file names (no directories, 15 chars max) and
293 // compressing each archive member.
295 Archive::writeToDisk(bool CreateSymbolTable, bool TruncateNames,
298 // Make sure they haven't opened up the file, not loaded it,
299 // but are now trying to write it which would wipe out the file.
300 if (members.empty() && mapfile && mapfile->getBufferSize() > 8) {
302 *ErrMsg = "Can't write an archive not opened for writing";
306 // Create a temporary file to store the archive in
307 sys::Path TmpArchive(archPath);
308 if (TmpArchive.createTemporaryFileOnDisk(ErrMsg))
311 // Make sure the temporary gets removed if we crash
312 sys::RemoveFileOnSignal(TmpArchive.str());
314 // Create archive file for output.
315 std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
317 std::ofstream ArchiveFile(TmpArchive.c_str(), io_mode);
319 // Check for errors opening or creating archive file.
320 if (!ArchiveFile.is_open() || ArchiveFile.bad()) {
321 TmpArchive.eraseFromDisk();
323 *ErrMsg = "Error opening archive file: " + archPath;
327 // If we're creating a symbol table, reset it now
328 if (CreateSymbolTable) {
333 // Write magic string to archive.
334 ArchiveFile << ARFILE_MAGIC;
336 // Loop over all member files, and write them out. Note that this also
337 // builds the symbol table, symTab.
338 for (MembersList::iterator I = begin(), E = end(); I != E; ++I) {
339 if (writeMember(*I, ArchiveFile, CreateSymbolTable,
340 TruncateNames, ErrMsg)) {
341 TmpArchive.eraseFromDisk();
347 // Close archive file.
350 // Write the symbol table
351 if (CreateSymbolTable) {
352 // At this point we have written a file that is a legal archive but it
353 // doesn't have a symbol table in it. To aid in faster reading and to
354 // ensure compatibility with other archivers we need to put the symbol
355 // table first in the file. Unfortunately, this means mapping the file
356 // we just wrote back in and copying it to the destination file.
357 sys::Path FinalFilePath(archPath);
359 // Map in the archive we just wrote.
361 OwningPtr<MemoryBuffer> arch;
362 if (error_code ec = MemoryBuffer::getFile(TmpArchive.c_str(), arch)) {
364 *ErrMsg = ec.message();
367 const char* base = arch->getBufferStart();
369 // Open another temporary file in order to avoid invalidating the
371 if (FinalFilePath.createTemporaryFileOnDisk(ErrMsg))
373 sys::RemoveFileOnSignal(FinalFilePath.str());
375 std::ofstream FinalFile(FinalFilePath.c_str(), io_mode);
376 if (!FinalFile.is_open() || FinalFile.bad()) {
377 TmpArchive.eraseFromDisk();
379 *ErrMsg = "Error opening archive file: " + FinalFilePath.str();
383 // Write the file magic number
384 FinalFile << ARFILE_MAGIC;
386 // If there is a foreign symbol table, put it into the file now. Most
387 // ar(1) implementations require the symbol table to be first but llvm-ar
388 // can deal with it being after a foreign symbol table. This ensures
389 // compatibility with other ar(1) implementations as well as allowing the
390 // archive to store both native .o and LLVM .bc files, both indexed.
392 if (writeMember(*foreignST, FinalFile, false, false, ErrMsg)) {
394 TmpArchive.eraseFromDisk();
399 // Copy the temporary file contents being sure to skip the file's magic
401 FinalFile.write(base + sizeof(ARFILE_MAGIC)-1,
402 arch->getBufferSize()-sizeof(ARFILE_MAGIC)+1);
408 // Move the final file over top of TmpArchive
409 if (FinalFilePath.renamePathOnDisk(TmpArchive, ErrMsg))
413 // Before we replace the actual archive, we need to forget all the
414 // members, since they point to data in that old archive. We need to do
415 // this because we cannot replace an open file on Windows.
418 if (TmpArchive.renamePathOnDisk(sys::Path(archPath), ErrMsg))
421 // Set correct read and write permissions after temporary file is moved
422 // to final destination path.
423 if (sys::Path(archPath).makeReadableOnDisk(ErrMsg))
425 if (sys::Path(archPath).makeWriteableOnDisk(ErrMsg))