diff options
Diffstat (limited to 'lib/Bytecode/Archive/ArchiveReader.cpp')
| -rw-r--r-- | lib/Bytecode/Archive/ArchiveReader.cpp | 540 |
1 files changed, 540 insertions, 0 deletions
diff --git a/lib/Bytecode/Archive/ArchiveReader.cpp b/lib/Bytecode/Archive/ArchiveReader.cpp new file mode 100644 index 0000000000..ff8c9bcb03 --- /dev/null +++ b/lib/Bytecode/Archive/ArchiveReader.cpp @@ -0,0 +1,540 @@ +//===-- ArchiveReader.cpp - Read LLVM archive files -------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file was developed by Reid Spencer and is distributed under the +// University of Illinois Open Source License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// Builds up standard unix archive files (.a) containing LLVM bytecode. +// +//===----------------------------------------------------------------------===// + +#include "ArchiveInternals.h" +#include "llvm/Bytecode/Reader.h" + +using namespace llvm; + +/// Read a variable-bit-rate encoded unsigned integer +inline unsigned readInteger(const char*&At, const char*End) { + unsigned Shift = 0; + unsigned Result = 0; + + do { + if (At == End) + throw std::string("Ran out of data reading vbr_uint!"); + Result |= (unsigned)((*At++) & 0x7F) << Shift; + Shift += 7; + } while (At[-1] & 0x80); + return Result; +} + +// Completely parse the Archive's symbol table and populate symTab member var. +void +Archive::parseSymbolTable(const void* data, unsigned size) { + const char* At = (const char*) data; + const char* End = At + size; + while (At < End) { + unsigned offset = readInteger(At, End); + unsigned length = readInteger(At, End); + if (At + length > End) + throw std::string("malformed symbol table"); + // we don't care if it can't be inserted (duplicate entry) + symTab.insert(std::make_pair(std::string(At, length), offset)); + At += length; + } + symTabSize = size; +} + +// This member parses an ArchiveMemberHeader that is presumed to be pointed to +// by At. The At pointer is updated to the byte just after the header, which +// can be variable in size. +ArchiveMember* +Archive::parseMemberHeader(const char*& At, const char* End) { + assert(At + sizeof(ArchiveMemberHeader) < End && "Not enough data"); + + // Cast archive member header + ArchiveMemberHeader* Hdr = (ArchiveMemberHeader*)At; + At += sizeof(ArchiveMemberHeader); + + // Instantiate the ArchiveMember to be filled + ArchiveMember* member = new ArchiveMember(this); + + // Extract the size and determine if the file is + // compressed or not (negative length). + int flags = 0; + int MemberSize = atoi(Hdr->size); + if (MemberSize < 0) { + flags |= ArchiveMember::CompressedFlag; + MemberSize = -MemberSize; + } + + // Check the size of the member for sanity + if (At + MemberSize > End) + throw std::string("invalid member length in archive file"); + + // Check the member signature + if (!Hdr->checkSignature()) + throw std::string("invalid file member signature"); + + // Convert and check the member name + // The empty name ( '/' and 15 blanks) is for a foreign (non-LLVM) symbol + // table. The special name "//" and 14 blanks is for a string table, used + // for long file names. This library doesn't generate either of those but + // it will accept them. If the name starts with #1/ and the remainder is + // digits, then those digits specify the length of the name that is + // stored immediately following the header. The special name + // __LLVM_SYM_TAB__ identifies the symbol table for LLVM bytecode. + // Anything else is a regular, short filename that is terminated with + // a '/' and blanks. + + std::string pathname; + switch (Hdr->name[0]) { + case '#': + if (Hdr->name[1] == '1' && Hdr->name[2] == '/') { + if (isdigit(Hdr->name[3])) { + unsigned len = atoi(&Hdr->name[3]); + pathname.assign(At, len); + At += len; + MemberSize -= len; + flags |= ArchiveMember::HasLongFilenameFlag; + } else + throw std::string("invalid long filename"); + } else if (Hdr->name[1] == '_' && + (0 == memcmp(Hdr->name, ARFILE_LLVM_SYMTAB_NAME, 16))) { + // The member is using a long file name (>15 chars) format. + // This format is standard for 4.4BSD and Mac OSX operating + // systems. LLVM uses it similarly. In this format, the + // remainder of the name field (after #1/) specifies the + // length of the file name which occupy the first bytes of + // the member's data. The pathname already has the #1/ stripped. + pathname.assign(ARFILE_LLVM_SYMTAB_NAME); + flags |= ArchiveMember::LLVMSymbolTableFlag; + } + break; + case '/': + if (Hdr->name[1]== '/') { + if (0 == memcmp(Hdr->name, ARFILE_STRTAB_NAME, 16)) { + pathname.assign(ARFILE_STRTAB_NAME); + flags |= ArchiveMember::StringTableFlag; + } else { + throw std::string("invalid string table name"); + } + } else if (Hdr->name[1] == ' ') { + if (0 == memcmp(Hdr->name, ARFILE_SVR4_SYMTAB_NAME, 16)) { + pathname.assign(ARFILE_SVR4_SYMTAB_NAME); + flags |= ArchiveMember::SVR4SymbolTableFlag; + } else { + throw std::string("invalid SVR4 symbol table name"); + } + } else if (isdigit(Hdr->name[1])) { + unsigned index = atoi(&Hdr->name[1]); + if (index < strtab.length()) { + const char* namep = strtab.c_str() + index; + const char* endp = strtab.c_str() + strtab.length(); + const char* p = namep; + const char* last_p = p; + while (p < endp) { + if (*p == '\n' && *last_p == '/') { + pathname.assign(namep, last_p - namep); + flags |= ArchiveMember::HasLongFilenameFlag; + break; + } + last_p = p; + p++; + } + if (p >= endp) + throw std::string("missing name termiantor in string table"); + } else { + throw std::string("name index beyond string table"); + } + } + break; + case '_': + if (Hdr->name[1] == '_' && + (0 == memcmp(Hdr->name, ARFILE_BSD4_SYMTAB_NAME, 16))) { + pathname.assign(ARFILE_BSD4_SYMTAB_NAME); + flags |= ArchiveMember::BSD4SymbolTableFlag; + break; + } + /* FALL THROUGH */ + + default: + char* slash = (char*) memchr(Hdr->name, '/', 16); + if (slash == 0) + slash = Hdr->name + 16; + pathname.assign(Hdr->name, slash - Hdr->name); + break; + } + + // Determine if this is a bytecode file + switch (sys::IdentifyFileType(At, 4)) { + case sys::BytecodeFileType: + flags |= ArchiveMember::BytecodeFlag; + break; + case sys::CompressedBytecodeFileType: + flags |= ArchiveMember::CompressedBytecodeFlag; + flags &= ~ArchiveMember::CompressedFlag; + break; + default: + flags &= ~(ArchiveMember::BytecodeFlag| + ArchiveMember::CompressedBytecodeFlag); + break; + } + + // Fill in fields of the ArchiveMember + member->next = 0; + member->prev = 0; + member->parent = this; + member->path.set(pathname); + member->info.fileSize = MemberSize; + member->info.modTime.fromEpochTime(atoi(Hdr->date)); + unsigned int mode; + sscanf(Hdr->mode, "%o", &mode); + member->info.mode = mode; + member->info.user = atoi(Hdr->uid); + member->info.group = atoi(Hdr->gid); + member->flags = flags; + member->data = At; + + return member; +} + +void +Archive::checkSignature() { + // Check the magic string at file's header + if (mapfile->size() < 8 || memcmp(base, ARFILE_MAGIC, 8)) + throw std::string("invalid signature for an archive file"); +} + +// This function loads the entire archive and fully populates its ilist with +// the members of the archive file. This is typically used in preparation for +// editing the contents of the archive. +void +Archive::loadArchive() { + + // Set up parsing + members.clear(); + symTab.clear(); + const char *At = base; + const char *End = base + mapfile->size(); + + checkSignature(); + At += 8; // Skip the magic string. + + bool seenSymbolTable = false; + bool foundFirstFile = false; + while (At < End) { + // parse the member header + const char* Save = At; + ArchiveMember* mbr = parseMemberHeader(At, End); + + // check if this is the foreign symbol table + if (mbr->isSVR4SymbolTable() || mbr->isBSD4SymbolTable()) { + // We just save this but don't do anything special + // with it. It doesn't count as the "first file". + if (foreignST) { + // What? Multiple foreign symbol tables? Just chuck it + // and retain the last one found. + delete foreignST; + } + foreignST = mbr; + At += mbr->getSize(); + if ((intptr_t(At) & 1) == 1) + At++; + } else if (mbr->isStringTable()) { + // Simply suck the entire string table into a string + // variable. This will be used to get the names of the + // members that use the "/ddd" format for their names + // (SVR4 style long names). + strtab.assign(At, mbr->getSize()); + At += mbr->getSize(); + if ((intptr_t(At) & 1) == 1) + At++; + delete mbr; + } else if (mbr->isLLVMSymbolTable()) { + // This is the LLVM symbol table for the archive. If we've seen it + // already, its an error. Otherwise, parse the symbol table and move on. + if (seenSymbolTable) + throw std::string("invalid archive: multiple symbol tables"); + parseSymbolTable(mbr->getData(), mbr->getSize()); + seenSymbolTable = true; + At += mbr->getSize(); + if ((intptr_t(At) & 1) == 1) + At++; + delete mbr; // We don't need this member in the list of members. + } else { + // This is just a regular file. If its the first one, save its offset. + // Otherwise just push it on the list and move on to the next file. + if (!foundFirstFile) { + firstFileOffset = Save - base; + foundFirstFile = true; + } + members.push_back(mbr); + At += mbr->getSize(); + if ((intptr_t(At) & 1) == 1) + At++; + } + } +} + +// Open and completely load the archive file. +Archive* +Archive::OpenAndLoad(const sys::Path& file, std::string* ErrorMessage) { + try { + std::auto_ptr<Archive> result ( new Archive(file, true)); + result->loadArchive(); + return result.release(); + } catch (const std::string& msg) { + if (ErrorMessage) { + *ErrorMessage = msg; + } + return 0; + } +} + +// Get all the bytecode modules from the archive +bool +Archive::getAllModules(std::vector<Module*>& Modules, std::string* ErrMessage) { + + for (iterator I=begin(), E=end(); I != E; ++I) { + if (I->isBytecode() || I->isCompressedBytecode()) { + std::string FullMemberName = archPath.toString() + + "(" + I->getPath().toString() + ")"; + Module* M = ParseBytecodeBuffer((const unsigned char*)I->getData(), + I->getSize(), FullMemberName, ErrMessage); + if (!M) + return true; + + Modules.push_back(M); + } + } + return false; +} + +// Load just the symbol table from the archive file +void +Archive::loadSymbolTable() { + + // Set up parsing + members.clear(); + symTab.clear(); + const char *At = base; + const char *End = base + mapfile->size(); + + // Make sure we're dealing with an archive + checkSignature(); + + At += 8; // Skip signature + + // Parse the first file member header + const char* FirstFile = At; + ArchiveMember* mbr = parseMemberHeader(At, End); + + if (mbr->isSVR4SymbolTable() || mbr->isBSD4SymbolTable()) { + // Skip the foreign symbol table, we don't do anything with it + At += mbr->getSize(); + if ((intptr_t(At) & 1) == 1) + At++; + delete mbr; + + // Read the next one + FirstFile = At; + mbr = parseMemberHeader(At, End); + } + + if (mbr->isStringTable()) { + // Process the string table entry + strtab.assign((const char*)mbr->getData(), mbr->getSize()); + At += mbr->getSize(); + if ((intptr_t(At) & 1) == 1) + At++; + delete mbr; + // Get the next one + FirstFile = At; + mbr = parseMemberHeader(At, End); + } + + // See if its the symbol table + if (mbr->isLLVMSymbolTable()) { + parseSymbolTable(mbr->getData(), mbr->getSize()); + At += mbr->getSize(); + if ((intptr_t(At) & 1) == 1) + At++; + FirstFile = At; + } else { + // There's no symbol table in the file. We have to rebuild it from scratch + // because the intent of this method is to get the symbol table loaded so + // it can be searched efficiently. + // Add the member to the members list + members.push_back(mbr); + } + + firstFileOffset = FirstFile - base; +} + +// Open the archive and load just the symbol tables +Archive* +Archive::OpenAndLoadSymbols(const sys::Path& file, std::string* ErrorMessage) { + try { + std::auto_ptr<Archive> result ( new Archive(file, true) ); + result->loadSymbolTable(); + return result.release(); + } catch (const std::string& msg) { + if (ErrorMessage) { + *ErrorMessage = msg; + } + return 0; + } +} + +// Look up one symbol in the symbol table and return a ModuleProvider for the +// module that defines that symbol. +ModuleProvider* +Archive::findModuleDefiningSymbol(const std::string& symbol) { + SymTabType::iterator SI = symTab.find(symbol); + if (SI == symTab.end()) + return 0; + + // The symbol table was previously constructed assuming that the members were + // written without the symbol table header. Because VBR encoding is used, the + // values could not be adjusted to account for the offset of the symbol table + // because that could affect the size of the symbol table due to VBR encoding. + // We now have to account for this by adjusting the offset by the size of the + // symbol table and its header. + unsigned fileOffset = + SI->second + // offset in symbol-table-less file + firstFileOffset; // add offset to first "real" file in archive + + // See if the module is already loaded + ModuleMap::iterator MI = modules.find(fileOffset); + if (MI != modules.end()) + return MI->second.first; + + // Module hasn't been loaded yet, we need to load it + const char* modptr = base + fileOffset; + ArchiveMember* mbr = parseMemberHeader(modptr, base + mapfile->size()); + + // Now, load the bytecode module to get the ModuleProvider + std::string FullMemberName = archPath.toString() + "(" + + mbr->getPath().toString() + ")"; + ModuleProvider* mp = getBytecodeBufferModuleProvider( + (const unsigned char*) mbr->getData(), mbr->getSize(), + FullMemberName, 0); + + modules.insert(std::make_pair(fileOffset, std::make_pair(mp, mbr))); + + return mp; +} + +// Look up multiple symbols in the symbol table and return a set of +// ModuleProviders that define those symbols. +void +Archive::findModulesDefiningSymbols(std::set<std::string>& symbols, + std::set<ModuleProvider*>& result) +{ + assert(mapfile && base && "Can't findModulesDefiningSymbols on new archive"); + if (symTab.empty()) { + // We don't have a symbol table, so we must build it now but lets also + // make sure that we populate the modules table as we do this to ensure + // that we don't load them twice when findModuleDefiningSymbol is called + // below. + + // Get a pointer to the first file + const char* At = ((const char*)base) + firstFileOffset; + const char* End = ((const char*)base) + mapfile->size(); + + while ( At < End) { + // Compute the offset to be put in the symbol table + unsigned offset = At - base - firstFileOffset; + + // Parse the file's header + ArchiveMember* mbr = parseMemberHeader(At, End); + + // If it contains symbols + if (mbr->isBytecode() || mbr->isCompressedBytecode()) { + // Get the symbols + std::vector<std::string> symbols; + std::string FullMemberName = archPath.toString() + "(" + + mbr->getPath().toString() + ")"; + ModuleProvider* MP = GetBytecodeSymbols((const unsigned char*)At, + mbr->getSize(), FullMemberName, symbols); + + if (MP) { + // Insert the module's symbols into the symbol table + for (std::vector<std::string>::iterator I = symbols.begin(), + E=symbols.end(); I != E; ++I ) { + symTab.insert(std::make_pair(*I, offset)); + } + // Insert the ModuleProvider and the ArchiveMember into the table of + // modules. + modules.insert(std::make_pair(offset, std::make_pair(MP, mbr))); + } else { + throw std::string("Can't parse bytecode member: ") + + mbr->getPath().toString(); + } + } + + // Go to the next file location + At += mbr->getSize(); + if ((intptr_t(At) & 1) == 1) + At++; + } + } + + // At this point we have a valid symbol table (one way or another) so we + // just use it to quickly find the symbols requested. + + for (std::set<std::string>::iterator I=symbols.begin(), + E=symbols.end(); I != E;) { + // See if this symbol exists + ModuleProvider* mp = findModuleDefiningSymbol(*I); + if (mp) { + // The symbol exists, insert the ModuleProvider into our result, + // duplicates wil be ignored + result.insert(mp); + + // Remove the symbol now that its been resolved, being careful to + // post-increment the iterator. + symbols.erase(I++); + } else { + ++I; + } + } +} + +bool Archive::isBytecodeArchive() { + // Make sure the symTab has been loaded. In most cases this should have been + // done when the archive was constructed, but still, this is just in case. + if (!symTab.size()) + loadSymbolTable(); + + // Now that we know it's been loaded, return true + // if it has a size + if (symTab.size()) return true; + + //We still can't be sure it isn't a bytecode archive + loadArchive(); + + std::vector<Module *> Modules; + std::string ErrorMessage; + + // Scan the archive, trying to load a bytecode member. We only load one to + // see if this works. + for (iterator I = begin(), E = end(); I != E; ++I) { + if (!I->isBytecode() && !I->isCompressedBytecode()) + continue; + + std::string FullMemberName = + archPath.toString() + "(" + I->getPath().toString() + ")"; + Module* M = ParseBytecodeBuffer((const unsigned char*)I->getData(), + I->getSize(), FullMemberName); + if (!M) + return false; // Couldn't parse bytecode, not a bytecode archive. + delete M; + return true; + } + + return false; +} |