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 std::string mbrPath = sys::path::filename(mbr.getPath());
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 (TruncateNames) {
112 const char* nm = mbrPath.c_str();
113 unsigned len = mbrPath.length();
114 size_t slashpos = mbrPath.rfind('/');
115 if (slashpos != std::string::npos) {
121 memcpy(hdr.name,nm,len);
123 } else if (mbrPath.length() < 16 && mbrPath.find('/') == std::string::npos) {
124 memcpy(hdr.name,mbrPath.c_str(),mbrPath.length());
125 hdr.name[mbrPath.length()] = '/';
127 std::string nm = "#1/";
128 nm += utostr(mbrPath.length());
129 memcpy(hdr.name,nm.data(),nm.length());
131 sz -= mbrPath.length();
133 sz += mbrPath.length();
134 writeLongName = true;
137 // Set the size field
140 sprintf(&buffer[1],"%-9u",(unsigned)-sz);
142 sprintf(buffer, "%-10u", (unsigned)sz);
144 memcpy(hdr.size,buffer,10);
146 return writeLongName;
149 // Insert a file into the archive before some other member. This also takes care
150 // of extracting the necessary flags and information from the file.
151 bool Archive::addFileBefore(StringRef filePath, iterator where,
152 std::string *ErrMsg) {
153 if (!sys::fs::exists(filePath)) {
155 *ErrMsg = "Can not add a non-existent file to archive";
159 ArchiveMember* mbr = new ArchiveMember(this);
162 mbr->path = filePath;
163 sys::PathWithStatus PWS(filePath);
164 const sys::FileStatus *FSInfo = PWS.getFileStatus(false, ErrMsg);
169 mbr->User = FSInfo->getUser();
170 mbr->Group = FSInfo->getGroup();
171 mbr->Mode = FSInfo->getMode();
172 mbr->ModTime = FSInfo->getTimestamp();
173 mbr->Size = FSInfo->getSize();
176 if (sys::path::filename(filePath).size() > 15)
177 flags |= ArchiveMember::HasLongFilenameFlag;
179 sys::fs::file_magic type;
180 if (sys::fs::identify_magic(mbr->path, type))
181 type = sys::fs::file_magic::unknown;
183 case sys::fs::file_magic::bitcode:
184 flags |= ArchiveMember::BitcodeFlag;
190 members.insert(where,mbr);
194 // Write one member out to the file.
196 Archive::writeMember(
197 const ArchiveMember& member,
198 std::ofstream& ARFile,
203 unsigned filepos = ARFile.tellp();
206 // Get the data and its size either from the
207 // member's in-memory data or directly from the file.
208 size_t fSize = member.getSize();
209 const char *data = (const char*)member.getData();
210 MemoryBuffer *mFile = 0;
212 OwningPtr<MemoryBuffer> File;
213 if (error_code ec = MemoryBuffer::getFile(member.getPath(), File)) {
215 *ErrMsg = ec.message();
219 data = mFile->getBufferStart();
220 fSize = mFile->getBufferSize();
225 // Compute the fields of the header
226 ArchiveMemberHeader Hdr;
227 bool writeLongName = fillHeader(member,Hdr,hdrSize,TruncateNames);
229 // Write header to archive file
230 ARFile.write((char*)&Hdr, sizeof(Hdr));
232 // Write the long filename if its long
234 ARFile.write(member.getPath().str().data(),
235 member.getPath().str().length());
238 // Write the (possibly compressed) member's content to the file.
239 ARFile.write(data,fSize);
241 // Make sure the member is an even length
242 if ((ARFile.tellp() & 1) == 1)
243 ARFile << ARFILE_PAD;
245 // Close the mapped file if it was opened
250 // Write the entire archive to the file specified when the archive was created.
251 // This writes to a temporary file first. Options are for creating a symbol
252 // table, flattening the file names (no directories, 15 chars max) and
253 // compressing each archive member.
254 bool Archive::writeToDisk(bool TruncateNames, std::string *ErrMsg) {
255 // Make sure they haven't opened up the file, not loaded it,
256 // but are now trying to write it which would wipe out the file.
257 if (members.empty() && mapfile && mapfile->getBufferSize() > 8) {
259 *ErrMsg = "Can't write an archive not opened for writing";
263 // Create a temporary file to store the archive in
264 sys::Path TmpArchive(archPath);
265 if (TmpArchive.createTemporaryFileOnDisk(ErrMsg))
268 // Make sure the temporary gets removed if we crash
269 sys::RemoveFileOnSignal(TmpArchive.str());
271 // Create archive file for output.
272 std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
274 std::ofstream ArchiveFile(TmpArchive.c_str(), io_mode);
276 // Check for errors opening or creating archive file.
277 if (!ArchiveFile.is_open() || ArchiveFile.bad()) {
278 TmpArchive.eraseFromDisk();
280 *ErrMsg = "Error opening archive file: " + archPath;
284 // Write magic string to archive.
285 ArchiveFile << ARFILE_MAGIC;
287 // Loop over all member files, and write them out. Note that this also
288 // builds the symbol table, symTab.
289 for (MembersList::iterator I = begin(), E = end(); I != E; ++I) {
290 if (writeMember(*I, ArchiveFile, TruncateNames, ErrMsg)) {
291 TmpArchive.eraseFromDisk();
297 // Close archive file.
300 // Before we replace the actual archive, we need to forget all the
301 // members, since they point to data in that old archive. We need to do
302 // this because we cannot replace an open file on Windows.
305 if (TmpArchive.renamePathOnDisk(sys::Path(archPath), ErrMsg))
308 // Set correct read and write permissions after temporary file is moved
309 // to final destination path.
310 if (sys::Path(archPath).makeReadableOnDisk(ErrMsg))
312 if (sys::Path(archPath).makeWriteableOnDisk(ErrMsg))