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Diffstat (limited to 'tools/llvm-ar/ArchiveReader.cpp')
| -rw-r--r-- | tools/llvm-ar/ArchiveReader.cpp | 557 |
1 files changed, 557 insertions, 0 deletions
diff --git a/tools/llvm-ar/ArchiveReader.cpp b/tools/llvm-ar/ArchiveReader.cpp new file mode 100644 index 0000000000..8ad01dca0b --- /dev/null +++ b/tools/llvm-ar/ArchiveReader.cpp @@ -0,0 +1,557 @@ +//===-- ArchiveReader.cpp - Read LLVM archive files -------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// Builds up standard unix archive files (.a) containing LLVM bitcode. +// +//===----------------------------------------------------------------------===// + +#include "Archive.h" +#include "ArchiveInternals.h" +#include "llvm/ADT/OwningPtr.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/Bitcode/ReaderWriter.h" +#include "llvm/IR/Module.h" +#include "llvm/Support/FileSystem.h" +#include "llvm/Support/MemoryBuffer.h" +#include <cstdio> +#include <cstdlib> +using namespace llvm; + +/// Read a variable-bit-rate encoded unsigned integer +static inline unsigned readInteger(const char*&At, const char*End) { + unsigned Shift = 0; + unsigned Result = 0; + + do { + if (At == End) + return Result; + Result |= (unsigned)((*At++) & 0x7F) << Shift; + Shift += 7; + } while (At[-1] & 0x80); + return Result; +} + +// 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, std::string* error) +{ + if (At + sizeof(ArchiveMemberHeader) >= End) { + if (error) + *error = "Unexpected end of file"; + return 0; + } + + // Cast archive member header + const ArchiveMemberHeader* Hdr = (const ArchiveMemberHeader*)At; + At += sizeof(ArchiveMemberHeader); + + int flags = 0; + int MemberSize = atoi(Hdr->size); + assert(MemberSize >= 0); + + // Check the size of the member for sanity + if (At + MemberSize > End) { + if (error) + *error = "invalid member length in archive file"; + return 0; + } + + // Check the member signature + if (!Hdr->checkSignature()) { + if (error) + *error = "invalid file member signature"; + return 0; + } + + // 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. 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]); + const char *nulp = (const char *)memchr(At, '\0', len); + pathname.assign(At, nulp != 0 ? (uintptr_t)(nulp - At) : len); + At += len; + MemberSize -= len; + flags |= ArchiveMember::HasLongFilenameFlag; + } else { + if (error) + *error = "invalid long filename"; + return 0; + } + } + break; + case '/': + if (Hdr->name[1]== '/') { + if (0 == memcmp(Hdr->name, ARFILE_STRTAB_NAME, 16)) { + pathname.assign(ARFILE_STRTAB_NAME); + flags |= ArchiveMember::StringTableFlag; + } else { + if (error) + *error = "invalid string table name"; + return 0; + } + } 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 { + if (error) + *error = "invalid SVR4 symbol table name"; + return 0; + } + } 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) { + if (error) + *error = "missing name terminator in string table"; + return 0; + } + } else { + if (error) + *error = "name index beyond string table"; + return 0; + } + } + 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: + const char* slash = (const 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 bitcode file + if (sys::fs::identify_magic(StringRef(At, 4)) == + sys::fs::file_magic::bitcode) + flags |= ArchiveMember::BitcodeFlag; + else + flags &= ~ArchiveMember::BitcodeFlag; + + // Instantiate the ArchiveMember to be filled + ArchiveMember* member = new ArchiveMember(this); + + // Fill in fields of the ArchiveMember + 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; +} + +bool +Archive::checkSignature(std::string* error) { + // Check the magic string at file's header + if (mapfile->getBufferSize() < 8 || memcmp(base, ARFILE_MAGIC, 8)) { + if (error) + *error = "invalid signature for an archive file"; + return false; + } + return true; +} + +// 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. +bool +Archive::loadArchive(std::string* error) { + + // Set up parsing + members.clear(); + symTab.clear(); + const char *At = base; + const char *End = mapfile->getBufferEnd(); + + if (!checkSignature(error)) + return false; + + At += 8; // Skip the magic string. + + bool foundFirstFile = false; + while (At < End) { + // parse the member header + const char* Save = At; + ArchiveMember* mbr = parseMemberHeader(At, End, error); + if (!mbr) + return false; + + // 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 { + // 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++; + } + } + return true; +} + +// Open and completely load the archive file. +Archive* +Archive::OpenAndLoad(const sys::Path& File, LLVMContext& C, + std::string* ErrorMessage) { + OwningPtr<Archive> result ( new Archive(File, C)); + if (result->mapToMemory(ErrorMessage)) + return NULL; + if (!result->loadArchive(ErrorMessage)) + return NULL; + return result.take(); +} + +// Get all the bitcode 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->isBitcode()) { + std::string FullMemberName = archPath.str() + + "(" + I->getPath().str() + ")"; + MemoryBuffer *Buffer = + MemoryBuffer::getMemBufferCopy(StringRef(I->getData(), I->getSize()), + FullMemberName.c_str()); + + Module *M = ParseBitcodeFile(Buffer, Context, ErrMessage); + delete Buffer; + if (!M) + return true; + + Modules.push_back(M); + } + } + return false; +} + +// Load just the symbol table from the archive file +bool +Archive::loadSymbolTable(std::string* ErrorMsg) { + + // Set up parsing + members.clear(); + symTab.clear(); + const char *At = base; + const char *End = mapfile->getBufferEnd(); + + // Make sure we're dealing with an archive + if (!checkSignature(ErrorMsg)) + return false; + + At += 8; // Skip signature + + // Parse the first file member header + const char* FirstFile = At; + ArchiveMember* mbr = parseMemberHeader(At, End, ErrorMsg); + if (!mbr) + return false; + + 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, ErrorMsg); + if (!mbr) { + delete mbr; + return false; + } + } + + 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, ErrorMsg); + if (!mbr) { + delete mbr; + return false; + } + } + + // 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; + return true; +} + +// Open the archive and load just the symbol tables +Archive* Archive::OpenAndLoadSymbols(const sys::Path& File, + LLVMContext& C, + std::string* ErrorMessage) { + OwningPtr<Archive> result ( new Archive(File, C) ); + if (result->mapToMemory(ErrorMessage)) + return NULL; + if (!result->loadSymbolTable(ErrorMessage)) + return NULL; + return result.take(); +} + +// Look up one symbol in the symbol table and return the module that defines +// that symbol. +Module* +Archive::findModuleDefiningSymbol(const std::string& symbol, + std::string* ErrMsg) { + 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, mapfile->getBufferEnd(), + ErrMsg); + if (!mbr) + return 0; + + // Now, load the bitcode module to get the Module. + std::string FullMemberName = archPath.str() + "(" + + mbr->getPath().str() + ")"; + MemoryBuffer *Buffer = + MemoryBuffer::getMemBufferCopy(StringRef(mbr->getData(), mbr->getSize()), + FullMemberName.c_str()); + + Module *m = getLazyBitcodeModule(Buffer, Context, ErrMsg); + if (!m) + return 0; + + modules.insert(std::make_pair(fileOffset, std::make_pair(m, mbr))); + + return m; +} + +// Look up multiple symbols in the symbol table and return a set of +// Modules that define those symbols. +bool +Archive::findModulesDefiningSymbols(std::set<std::string>& symbols, + SmallVectorImpl<Module*>& result, + std::string* error) { + if (!mapfile || !base) { + if (error) + *error = "Empty archive invalid for finding modules defining symbols"; + return false; + } + + 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 = base + firstFileOffset; + const char* End = mapfile->getBufferEnd(); + + 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, error); + if (!mbr) + return false; + + // If it contains symbols + if (mbr->isBitcode()) { + // Get the symbols + std::vector<std::string> symbols; + std::string FullMemberName = archPath.str() + "(" + + mbr->getPath().str() + ")"; + Module* M = + GetBitcodeSymbols(At, mbr->getSize(), FullMemberName, Context, + symbols, error); + + if (M) { + // 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 Module and the ArchiveMember into the table of + // modules. + modules.insert(std::make_pair(offset, std::make_pair(M, mbr))); + } else { + if (error) + *error = "Can't parse bitcode member: " + + mbr->getPath().str() + ": " + *error; + delete mbr; + return false; + } + } + + // 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. + + SmallPtrSet<Module*, 16> Added; + for (std::set<std::string>::iterator I=symbols.begin(), + Next = I, + E=symbols.end(); I != E; I = Next) { + // Increment Next before we invalidate it. + ++Next; + + // See if this symbol exists + Module* m = findModuleDefiningSymbol(*I,error); + if (!m) + continue; + bool NewMember = Added.insert(m); + if (!NewMember) + continue; + + // The symbol exists, insert the Module into our result. + result.push_back(m); + + // Remove the symbol now that its been resolved. + symbols.erase(I); + } + return true; +} + +bool Archive::isBitcodeArchive() { + // 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.empty()) + if (!loadSymbolTable(0)) + return false; + + // 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 bitcode archive + if (!loadArchive(0)) + return false; + + std::vector<Module *> Modules; + std::string ErrorMessage; + + // Scan the archive, trying to load a bitcode member. We only load one to + // see if this works. + for (iterator I = begin(), E = end(); I != E; ++I) { + if (!I->isBitcode()) + continue; + + std::string FullMemberName = + archPath.str() + "(" + I->getPath().str() + ")"; + + MemoryBuffer *Buffer = + MemoryBuffer::getMemBufferCopy(StringRef(I->getData(), I->getSize()), + FullMemberName.c_str()); + Module *M = ParseBitcodeFile(Buffer, Context); + delete Buffer; + if (!M) + return false; // Couldn't parse bitcode, not a bitcode archive. + delete M; + return true; + } + + return false; +} |