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,
212 unsigned filepos = ARFile.tellp();
215 // Get the data and its size either from the
216 // member's in-memory data or directly from the file.
217 size_t fSize = member.getSize();
218 const char *data = (const char*)member.getData();
219 MemoryBuffer *mFile = 0;
221 OwningPtr<MemoryBuffer> File;
222 if (error_code ec = MemoryBuffer::getFile(member.getPath(), File)) {
224 *ErrMsg = ec.message();
228 data = mFile->getBufferStart();
229 fSize = mFile->getBufferSize();
234 // Compute the fields of the header
235 ArchiveMemberHeader Hdr;
236 bool writeLongName = fillHeader(member,Hdr,hdrSize,TruncateNames);
238 // Write header to archive file
239 ARFile.write((char*)&Hdr, sizeof(Hdr));
241 // Write the long filename if its long
243 ARFile.write(member.getPath().str().data(),
244 member.getPath().str().length());
247 // Write the (possibly compressed) member's content to the file.
248 ARFile.write(data,fSize);
250 // Make sure the member is an even length
251 if ((ARFile.tellp() & 1) == 1)
252 ARFile << ARFILE_PAD;
254 // Close the mapped file if it was opened
259 // Write the entire archive to the file specified when the archive was created.
260 // This writes to a temporary file first. Options are for creating a symbol
261 // table, flattening the file names (no directories, 15 chars max) and
262 // compressing each archive member.
263 bool Archive::writeToDisk(bool TruncateNames, std::string *ErrMsg) {
264 // Make sure they haven't opened up the file, not loaded it,
265 // but are now trying to write it which would wipe out the file.
266 if (members.empty() && mapfile && mapfile->getBufferSize() > 8) {
268 *ErrMsg = "Can't write an archive not opened for writing";
272 // Create a temporary file to store the archive in
273 sys::Path TmpArchive(archPath);
274 if (TmpArchive.createTemporaryFileOnDisk(ErrMsg))
277 // Make sure the temporary gets removed if we crash
278 sys::RemoveFileOnSignal(TmpArchive.str());
280 // Create archive file for output.
281 std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
283 std::ofstream ArchiveFile(TmpArchive.c_str(), io_mode);
285 // Check for errors opening or creating archive file.
286 if (!ArchiveFile.is_open() || ArchiveFile.bad()) {
287 TmpArchive.eraseFromDisk();
289 *ErrMsg = "Error opening archive file: " + archPath;
293 // Write magic string to archive.
294 ArchiveFile << ARFILE_MAGIC;
296 // Loop over all member files, and write them out. Note that this also
297 // builds the symbol table, symTab.
298 for (MembersList::iterator I = begin(), E = end(); I != E; ++I) {
299 if (writeMember(*I, ArchiveFile, TruncateNames, ErrMsg)) {
300 TmpArchive.eraseFromDisk();
306 // Close archive file.
309 // Before we replace the actual archive, we need to forget all the
310 // members, since they point to data in that old archive. We need to do
311 // this because we cannot replace an open file on Windows.
314 if (TmpArchive.renamePathOnDisk(sys::Path(archPath), ErrMsg))
317 // Set correct read and write permissions after temporary file is moved
318 // to final destination path.
319 if (sys::Path(archPath).makeReadableOnDisk(ErrMsg))
321 if (sys::Path(archPath).makeWriteableOnDisk(ErrMsg))