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/PathV1.h"
22 #include "llvm/Support/Process.h"
23 #include "llvm/Support/Signals.h"
24 #include "llvm/Support/system_error.h"
30 // Write an integer using variable bit rate encoding. This saves a few bytes
31 // per entry in the symbol table.
32 static inline void writeInteger(unsigned num, std::ofstream& ARFile) {
34 if (num < 0x80) { // done?
35 ARFile << (unsigned char)num;
39 // Nope, we are bigger than a character, output the next 7 bits and set the
40 // high bit to say that there is more coming...
41 ARFile << (unsigned char)(0x80 | ((unsigned char)num & 0x7F));
42 num >>= 7; // Shift out 7 bits now...
46 // Compute how many bytes are taken by a given VBR encoded value. This is needed
47 // to pre-compute the size of the symbol table.
48 static inline unsigned numVbrBytes(unsigned num) {
50 // Note that the following nested ifs are somewhat equivalent to a binary
51 // search. We split it in half by comparing against 2^14 first. This allows
52 // most reasonable values to be done in 2 comparisons instead of 1 for
53 // small ones and four for large ones. We expect this to access file offsets
54 // in the 2^10 to 2^24 range and symbol lengths in the 2^0 to 2^8 range,
55 // so this approach is reasonable.
67 return 5; // anything >= 2^28 takes 5 bytes
70 // Create an empty archive.
71 Archive* Archive::CreateEmpty(StringRef FilePath, LLVMContext& C) {
72 Archive* result = new Archive(FilePath, C);
76 // Fill the ArchiveMemberHeader with the information from a member. If
77 // TruncateNames is true, names are flattened to 15 chars or less. The sz field
78 // is provided here instead of coming from the mbr because the member might be
79 // stored compressed and the compressed size is not the ArchiveMember's size.
80 // Furthermore compressed files have negative size fields to identify them as
83 Archive::fillHeader(const ArchiveMember &mbr, ArchiveMemberHeader& hdr,
84 int sz, bool TruncateNames) const {
86 // Set the permissions mode, uid and gid
89 sprintf(buffer, "%-8o", mbr.getMode());
90 memcpy(hdr.mode,buffer,8);
91 sprintf(buffer, "%-6u", mbr.getUser());
92 memcpy(hdr.uid,buffer,6);
93 sprintf(buffer, "%-6u", mbr.getGroup());
94 memcpy(hdr.gid,buffer,6);
96 // Set the last modification date
97 uint64_t secondsSinceEpoch = mbr.getModTime().toEpochTime();
98 sprintf(buffer,"%-12u", unsigned(secondsSinceEpoch));
99 memcpy(hdr.date,buffer,12);
101 // Get rid of trailing blanks in the name
102 std::string mbrPath = mbr.getPath().str();
103 size_t mbrLen = mbrPath.length();
104 while (mbrLen > 0 && mbrPath[mbrLen-1] == ' ') {
105 mbrPath.erase(mbrLen-1,1);
109 // Set the name field in one of its various flavors.
110 bool writeLongName = false;
111 if (mbr.isStringTable()) {
112 memcpy(hdr.name,ARFILE_STRTAB_NAME,16);
113 } else if (mbr.isSVR4SymbolTable()) {
114 memcpy(hdr.name,ARFILE_SVR4_SYMTAB_NAME,16);
115 } else if (mbr.isBSD4SymbolTable()) {
116 memcpy(hdr.name,ARFILE_BSD4_SYMTAB_NAME,16);
117 } else if (TruncateNames) {
118 const char* nm = mbrPath.c_str();
119 unsigned len = mbrPath.length();
120 size_t slashpos = mbrPath.rfind('/');
121 if (slashpos != std::string::npos) {
127 memcpy(hdr.name,nm,len);
129 } else if (mbrPath.length() < 16 && mbrPath.find('/') == std::string::npos) {
130 memcpy(hdr.name,mbrPath.c_str(),mbrPath.length());
131 hdr.name[mbrPath.length()] = '/';
133 std::string nm = "#1/";
134 nm += utostr(mbrPath.length());
135 memcpy(hdr.name,nm.data(),nm.length());
137 sz -= mbrPath.length();
139 sz += mbrPath.length();
140 writeLongName = true;
143 // Set the size field
146 sprintf(&buffer[1],"%-9u",(unsigned)-sz);
148 sprintf(buffer, "%-10u", (unsigned)sz);
150 memcpy(hdr.size,buffer,10);
152 return writeLongName;
155 // Insert a file into the archive before some other member. This also takes care
156 // of extracting the necessary flags and information from the file.
157 bool Archive::addFileBefore(StringRef filePath, iterator where,
158 std::string *ErrMsg) {
159 if (!sys::fs::exists(filePath)) {
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);
175 mbr->User = FSInfo->getUser();
176 mbr->Group = FSInfo->getGroup();
177 mbr->Mode = FSInfo->getMode();
178 mbr->ModTime = FSInfo->getTimestamp();
179 mbr->Size = FSInfo->getSize();
182 bool hasSlash = filePath.str().find('/') != std::string::npos;
184 flags |= ArchiveMember::HasPathFlag;
185 if (hasSlash || filePath.str().length() > 15)
186 flags |= ArchiveMember::HasLongFilenameFlag;
188 sys::fs::file_magic type;
189 if (sys::fs::identify_magic(mbr->path, type))
190 type = sys::fs::file_magic::unknown;
192 case sys::fs::file_magic::bitcode:
193 flags |= ArchiveMember::BitcodeFlag;
199 members.insert(where,mbr);
203 // Write one member out to the file.
205 Archive::writeMember(
206 const ArchiveMember& member,
207 std::ofstream& ARFile,
208 bool CreateSymbolTable,
213 unsigned filepos = ARFile.tellp();
216 // Get the data and its size either from the
217 // member's in-memory data or directly from the file.
218 size_t fSize = member.getSize();
219 const char *data = (const char*)member.getData();
220 MemoryBuffer *mFile = 0;
222 OwningPtr<MemoryBuffer> File;
223 if (error_code ec = MemoryBuffer::getFile(member.getPath(), File)) {
225 *ErrMsg = ec.message();
229 data = mFile->getBufferStart();
230 fSize = mFile->getBufferSize();
233 // Now that we have the data in memory, update the
234 // symbol table if it's a bitcode file.
235 if (CreateSymbolTable && member.isBitcode()) {
236 std::vector<std::string> symbols;
237 std::string FullMemberName =
238 (archPath + "(" + member.getPath() + ")").str();
240 GetBitcodeSymbols(data, fSize, FullMemberName, Context, symbols, ErrMsg);
242 // If the bitcode parsed successfully
244 for (std::vector<std::string>::iterator SI = symbols.begin(),
245 SE = symbols.end(); SI != SE; ++SI) {
247 std::pair<SymTabType::iterator,bool> Res =
248 symTab.insert(std::make_pair(*SI,filepos));
251 symTabSize += SI->length() +
252 numVbrBytes(SI->length()) +
253 numVbrBytes(filepos);
256 // We don't need this module any more.
261 *ErrMsg = "Can't parse bitcode member: " + member.getPath().str()
269 // Compute the fields of the header
270 ArchiveMemberHeader Hdr;
271 bool writeLongName = fillHeader(member,Hdr,hdrSize,TruncateNames);
273 // Write header to archive file
274 ARFile.write((char*)&Hdr, sizeof(Hdr));
276 // Write the long filename if its long
278 ARFile.write(member.getPath().str().data(),
279 member.getPath().str().length());
282 // Write the (possibly compressed) member's content to the file.
283 ARFile.write(data,fSize);
285 // Make sure the member is an even length
286 if ((ARFile.tellp() & 1) == 1)
287 ARFile << ARFILE_PAD;
289 // Close the mapped file if it was opened
294 // Write the entire archive to the file specified when the archive was created.
295 // This writes to a temporary file first. Options are for creating a symbol
296 // table, flattening the file names (no directories, 15 chars max) and
297 // compressing each archive member.
299 Archive::writeToDisk(bool CreateSymbolTable, bool TruncateNames,
302 // Make sure they haven't opened up the file, not loaded it,
303 // but are now trying to write it which would wipe out the file.
304 if (members.empty() && mapfile && mapfile->getBufferSize() > 8) {
306 *ErrMsg = "Can't write an archive not opened for writing";
310 // Create a temporary file to store the archive in
311 sys::Path TmpArchive(archPath);
312 if (TmpArchive.createTemporaryFileOnDisk(ErrMsg))
315 // Make sure the temporary gets removed if we crash
316 sys::RemoveFileOnSignal(TmpArchive.str());
318 // Create archive file for output.
319 std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
321 std::ofstream ArchiveFile(TmpArchive.c_str(), io_mode);
323 // Check for errors opening or creating archive file.
324 if (!ArchiveFile.is_open() || ArchiveFile.bad()) {
325 TmpArchive.eraseFromDisk();
327 *ErrMsg = "Error opening archive file: " + archPath;
331 // If we're creating a symbol table, reset it now
332 if (CreateSymbolTable) {
337 // Write magic string to archive.
338 ArchiveFile << ARFILE_MAGIC;
340 // Loop over all member files, and write them out. Note that this also
341 // builds the symbol table, symTab.
342 for (MembersList::iterator I = begin(), E = end(); I != E; ++I) {
343 if (writeMember(*I, ArchiveFile, CreateSymbolTable,
344 TruncateNames, ErrMsg)) {
345 TmpArchive.eraseFromDisk();
351 // Close archive file.
354 // Write the symbol table
355 if (CreateSymbolTable) {
356 // At this point we have written a file that is a legal archive but it
357 // doesn't have a symbol table in it. To aid in faster reading and to
358 // ensure compatibility with other archivers we need to put the symbol
359 // table first in the file. Unfortunately, this means mapping the file
360 // we just wrote back in and copying it to the destination file.
361 sys::Path FinalFilePath(archPath);
363 // Map in the archive we just wrote.
365 OwningPtr<MemoryBuffer> arch;
366 if (error_code ec = MemoryBuffer::getFile(TmpArchive.c_str(), arch)) {
368 *ErrMsg = ec.message();
371 const char* base = arch->getBufferStart();
373 // Open another temporary file in order to avoid invalidating the
375 if (FinalFilePath.createTemporaryFileOnDisk(ErrMsg))
377 sys::RemoveFileOnSignal(FinalFilePath.str());
379 std::ofstream FinalFile(FinalFilePath.c_str(), io_mode);
380 if (!FinalFile.is_open() || FinalFile.bad()) {
381 TmpArchive.eraseFromDisk();
383 *ErrMsg = "Error opening archive file: " + FinalFilePath.str();
387 // Write the file magic number
388 FinalFile << ARFILE_MAGIC;
390 // If there is a foreign symbol table, put it into the file now. Most
391 // ar(1) implementations require the symbol table to be first but llvm-ar
392 // can deal with it being after a foreign symbol table. This ensures
393 // compatibility with other ar(1) implementations as well as allowing the
394 // archive to store both native .o and LLVM .bc files, both indexed.
396 if (writeMember(*foreignST, FinalFile, false, false, ErrMsg)) {
398 TmpArchive.eraseFromDisk();
403 // Copy the temporary file contents being sure to skip the file's magic
405 FinalFile.write(base + sizeof(ARFILE_MAGIC)-1,
406 arch->getBufferSize()-sizeof(ARFILE_MAGIC)+1);
412 // Move the final file over top of TmpArchive
413 if (FinalFilePath.renamePathOnDisk(TmpArchive, ErrMsg))
417 // Before we replace the actual archive, we need to forget all the
418 // members, since they point to data in that old archive. We need to do
419 // this because we cannot replace an open file on Windows.
422 if (TmpArchive.renamePathOnDisk(sys::Path(archPath), ErrMsg))
425 // Set correct read and write permissions after temporary file is moved
426 // to final destination path.
427 if (sys::Path(archPath).makeReadableOnDisk(ErrMsg))
429 if (sys::Path(archPath).makeWriteableOnDisk(ErrMsg))