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::fs::file_status Status;
164 error_code EC = sys::fs::status(filePath, Status);
169 mbr->User = Status.getUser();
170 mbr->Group = Status.getGroup();
171 mbr->Mode = Status.permissions();
172 mbr->ModTime = Status.getLastModificationTime();
173 // FIXME: On posix this is a second stat.
174 EC = sys::fs::file_size(filePath, mbr->Size);
181 if (sys::path::filename(filePath).size() > 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 raw_fd_ostream& ARFile,
208 uint64_t filepos = ARFile.tell();
211 // Get the data and its size either from the
212 // member's in-memory data or directly from the file.
213 size_t fSize = member.getSize();
214 const char *data = (const char*)member.getData();
215 MemoryBuffer *mFile = 0;
217 OwningPtr<MemoryBuffer> File;
218 if (error_code ec = MemoryBuffer::getFile(member.getPath(), File)) {
220 *ErrMsg = ec.message();
224 data = mFile->getBufferStart();
225 fSize = mFile->getBufferSize();
230 // Compute the fields of the header
231 ArchiveMemberHeader Hdr;
232 bool writeLongName = fillHeader(member,Hdr,hdrSize,TruncateNames);
234 // Write header to archive file
235 ARFile.write((char*)&Hdr, sizeof(Hdr));
237 // Write the long filename if its long
239 StringRef Name = sys::path::filename(member.getPath());
240 ARFile.write(Name.data(), Name.size());
243 // Write the (possibly compressed) member's content to the file.
244 ARFile.write(data,fSize);
246 // Make sure the member is an even length
247 if ((ARFile.tell() & 1) == 1)
248 ARFile << ARFILE_PAD;
250 // Close the mapped file if it was opened
255 // Write the entire archive to the file specified when the archive was created.
256 // This writes to a temporary file first. Options are for creating a symbol
257 // table, flattening the file names (no directories, 15 chars max) and
258 // compressing each archive member.
259 bool Archive::writeToDisk(bool TruncateNames, std::string *ErrMsg) {
260 // Make sure they haven't opened up the file, not loaded it,
261 // but are now trying to write it which would wipe out the file.
262 if (members.empty() && mapfile && mapfile->getBufferSize() > 8) {
264 *ErrMsg = "Can't write an archive not opened for writing";
268 // Create a temporary file to store the archive in
270 SmallString<128> TmpArchive;
271 error_code EC = sys::fs::unique_file("temp-archive-%%%%%%%.a", TmpArchiveFD,
276 // Make sure the temporary gets removed if we crash
277 sys::RemoveFileOnSignal(TmpArchive);
279 // Create archive file for output.
280 raw_fd_ostream ArchiveFile(TmpArchiveFD, true);
282 // Write magic string to archive.
283 ArchiveFile << ARFILE_MAGIC;
285 // Loop over all member files, and write them out. Note that this also
286 // builds the symbol table, symTab.
287 for (MembersList::iterator I = begin(), E = end(); I != E; ++I) {
288 if (writeMember(*I, ArchiveFile, TruncateNames, ErrMsg)) {
289 sys::fs::remove(Twine(TmpArchive));
295 // Close archive file.
298 // Before we replace the actual archive, we need to forget all the
299 // members, since they point to data in that old archive. We need to do
300 // this because we cannot replace an open file on Windows.
303 if (sys::fs::rename(Twine(TmpArchive), archPath)) {
304 *ErrMsg = EC.message();
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))