From f0c201b34dbb943ead1ff5fe1754129ad2d373ec Mon Sep 17 00:00:00 2001 From: Reid Spencer Date: Sun, 14 Nov 2004 21:58:33 +0000 Subject: [PATCH] Completely rewritten to allow reading of archives and symbol table lookup in a more efficient manner. llvm-svn: 17767 --- llvm/lib/Bytecode/Archive/ArchiveReader.cpp | 533 ++++++++++++++------ 1 file changed, 371 insertions(+), 162 deletions(-) diff --git a/llvm/lib/Bytecode/Archive/ArchiveReader.cpp b/llvm/lib/Bytecode/Archive/ArchiveReader.cpp index b39dd7e58400..ae1a93307891 100644 --- a/llvm/lib/Bytecode/Archive/ArchiveReader.cpp +++ b/llvm/lib/Bytecode/Archive/ArchiveReader.cpp @@ -1,194 +1,403 @@ -//===- lib/Archive/ArchiveReader.cpp - Read LLVM archive files ------------===// +//===-- ArchiveReader.cpp - Read LLVM archive files -------------*- C++ -*-===// // // The LLVM Compiler Infrastructure // -// This file was developed by the LLVM research group and is distributed under -// the University of Illinois Open Source License. See LICENSE.TXT for details. +// This file was developed by Reid Spencer and is distributed under the +// University of Illinois Open Source License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // -// This file implements the ReadArchiveFile interface, which allows a linker to -// read all of the LLVM bytecode files contained in a .a file. This file -// understands the standard system .a file format. This can only handle the .a -// variant prevalent on Linux systems so far, but may be extended. See -// information in this source file for more information: -// http://sources.redhat.com/cgi-bin/cvsweb.cgi/src/bfd/archive.c?cvsroot=src +// Builds up standard unix archive files (.a) containing LLVM bytecode. // //===----------------------------------------------------------------------===// +#include "ArchiveInternals.h" #include "llvm/Bytecode/Reader.h" -#include "llvm/Module.h" -#include "llvm/Support/FileUtilities.h" -#include -#include + using namespace llvm; namespace { - struct ar_hdr { - char name[16]; - char date[12]; - char uid[6]; - char gid[6]; - char mode[8]; - char size[10]; - char fmag[2]; // Always equal to '`\n' - }; - enum ObjectType { - UserObject, // A user .o/.bc file - Unknown, // Unknown file, just ignore it - SVR4LongFilename, // a "//" section used for long file names - ArchiveSymbolTable, // Symbol table produced by ranlib. - }; +/// 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; } -/// getObjectType - Determine the type of object that this header represents. -/// This is capable of parsing the variety of special sections used for various -/// purposes. -/// -static enum ObjectType getObjectType(ar_hdr *H, std::string MemberName, - unsigned char *MemberData, unsigned Size) { - // Check for sections with special names... - if (MemberName == "__.SYMDEF " || MemberName == "__.SYMDEF SORTED") - return ArchiveSymbolTable; - else if (MemberName == "// ") - return SVR4LongFilename; - - // Check to see if it looks like an llvm object file... - if (Size >= 4 && !memcmp(MemberData, "llvm", 4)) - return UserObject; - - if (Size >= 4 && !memcmp(MemberData, "llvc", 4)) - return UserObject; - - return Unknown; } -static inline bool Error(std::string *ErrorStr, const char *Message) { - if (ErrorStr) *ErrorStr = Message; - return true; +// 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; } -static bool ParseSymbolTableSection(unsigned char *Buffer, unsigned Size, - std::string *S) { - // Currently not supported (succeeds without doing anything) +// 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; + unsigned index; + 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 + 1; // terminated by \n + 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_SYMTAB_NAME,16)) { + pathname.assign(ARFILE_SYMTAB_NAME); + flags |= ArchiveMember::ForeignSymbolTableFlag; + } else { + throw std::string("invalid foreign 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; + + default: + char* slash = (char*) memchr(Hdr->name,'/',16); + if (slash == 0) + throw std::string("missing name terminator"); + 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.setFile(pathname); + member->info.fileSize = MemberSize; + member->info.modTime.fromEpochTime(atoi(Hdr->date)); + sscanf(Hdr->mode,"%o",&(member->info.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->isForeignSymbolTable()) { + // We don't do anything with this but delete it + At += mbr->getSize(); + delete mbr; + if ((int(At) & 1) == 1) + At++; + } else if (mbr->isStringTable()) { + strtab.assign(At,mbr->getSize()); + At += mbr->getSize(); + if ((int(At) & 1) == 1) + At++; + delete mbr; + } else if (mbr->isLLVMSymbolTable()) { + if (seenSymbolTable) + throw std::string("invalid archive: multiple symbol tables"); + parseSymbolTable(mbr->getData(),mbr->getSize()); + seenSymbolTable = true; + At += mbr->getSize(); + if ((int(At) & 1) == 1) + At++; + delete mbr; + } else { + if (!foundFirstFile) { + firstFileOffset = Save - base; + foundFirstFile = true; + } + members.push_back(mbr); + At += mbr->getSize(); + if ((int(At) & 1) == 1) + At++; + } + } +} + +// Open and completely load the archive file. +Archive* +Archive::OpenAndLoad(const sys::Path& file) { + + Archive* result = new Archive(file,true); + + result->loadArchive(); + + return result; +} + +// Get all the bytecode modules from the archive +bool +Archive::getAllModules(std::vector& Modules, std::string* ErrMessage) { + + for (iterator I=begin(), E=end(); I != E; ++I) { + if (I->isBytecode() || I->isCompressedBytecode()) { + Module* M = ParseBytecodeBuffer((const unsigned char*)I->getData(), + I->getSize(), I->getPath().get(), ErrMessage); + if (!M) + return true; + + Modules.push_back(M); + } + } return false; } -static bool ReadArchiveBuffer(const std::string &ArchiveName, - unsigned char *Buffer, unsigned Length, - std::vector &Objects, - std::string *ErrorStr) { - if (Length < 8 || memcmp(Buffer, "!\n", 8)) - return Error(ErrorStr, "signature incorrect for an archive file!"); - Buffer += 8; Length -= 8; // Skip the magic string. +// Load just the symbol table from the archive file +void +Archive::loadSymbolTable() { - std::vector LongFilenames; + // Set up parsing + members.clear(); + symTab.clear(); + const char *At = base; + const char *End = base + mapfile->size(); - while (Length >= sizeof(ar_hdr)) { - ar_hdr *Hdr = (ar_hdr*)Buffer; - unsigned SizeFromHeader = atoi(Hdr->size); - if (SizeFromHeader + sizeof(ar_hdr) > Length) - return Error(ErrorStr, "invalid record length in archive file!"); + // Make sure we're dealing with an archive + checkSignature(); - unsigned char *MemberData = Buffer + sizeof(ar_hdr); - unsigned MemberSize = SizeFromHeader; - // Get name of archive member. - char *startp = Hdr->name; - char *endp = (char *) memchr (startp, '/', sizeof(ar_hdr)); - if (memcmp (Hdr->name, "#1/", 3) == 0) { - // 4.4BSD/MacOSX long filenames are abbreviated as "#1/L", where L is an - // ASCII-coded decimal number representing the length of the name buffer, - // which is prepended to the archive member's contents. - unsigned NameLength = atoi (&Hdr->name[3]); - startp = (char *) MemberData; - endp = startp + NameLength; - MemberData += NameLength; - MemberSize -= NameLength; - } else if (startp == endp && isdigit (Hdr->name[1])) { - // SVR4 long filenames are abbreviated as "/I", where I is - // an ASCII-coded decimal index into the LongFilenames vector. - unsigned NameIndex = atoi (&Hdr->name[1]); - assert (LongFilenames.size () > NameIndex - && "SVR4-style long filename for archive member not found"); - startp = &LongFilenames[NameIndex]; - endp = strchr (startp, '/'); - } else if (startp == endp && Hdr->name[1] == '/') { - // This is for the SVR4 long filename table (there might be other - // names starting with // but I don't know about them). Make sure that - // getObjectType sees it. - endp = &Hdr->name[sizeof (Hdr->name)]; + At += 8; // Skip signature + + // Parse the first file member header + const char* FirstFile = At; + ArchiveMember* mbr = parseMemberHeader(At, End); + + if (mbr->isForeignSymbolTable()) { + // Skip the foreign symbol table, we don't do anything with it + At += mbr->getSize(); + delete mbr; + + // See if there's a string table too + FirstFile = At; + mbr = parseMemberHeader(At,End); + if (mbr->isStringTable()) { + strtab.assign((const char*)mbr->getData(),mbr->getSize()); + At += mbr->getSize(); + delete mbr; + FirstFile = At; + mbr = parseMemberHeader(At,End); } - if (!endp) { - // 4.4BSD/MacOSX *short* filenames are not guaranteed to have a - // terminator. Start at the end of the field and backtrack over spaces. - endp = startp + sizeof(Hdr->name); - while (endp[-1] == ' ') - --endp; - } - std::string MemberName (startp, endp); - std::string FullMemberName = ArchiveName + "(" + MemberName + ")"; - - switch (getObjectType(Hdr, MemberName, MemberData, MemberSize)) { - case SVR4LongFilename: - // If this is a long filename section, read all of the file names into the - // LongFilenames vector. - LongFilenames.assign (MemberData, MemberData + MemberSize); - break; - case UserObject: { - Module *M = ParseBytecodeBuffer(MemberData, MemberSize, - FullMemberName, ErrorStr); - if (!M) return true; - Objects.push_back(M); - break; - } - case ArchiveSymbolTable: - if (ParseSymbolTableSection(MemberData, MemberSize, ErrorStr)) - return true; - break; - default: - std::cerr << "ReadArchiveBuffer: WARNING: Skipping unknown file: " - << FullMemberName << "\n"; - break; // Just ignore unknown files. - } - - // Round SizeFromHeader up to an even number... - SizeFromHeader = (SizeFromHeader+1)/2*2; - Buffer += sizeof(ar_hdr)+SizeFromHeader; // Move to the next entry - Length -= sizeof(ar_hdr)+SizeFromHeader; } - return Length != 0; -} - - -// ReadArchiveFile - Read bytecode files from the specified .a file, returning -// true on error, or false on success. This does not support reading files from -// standard input. -// -bool llvm::ReadArchiveFile(const std::string &Filename, - std::vector &Objects,std::string *ErrorStr){ - unsigned Length; - - // mmap in the file all at once... - unsigned char *Buffer = - (unsigned char*)ReadFileIntoAddressSpace(Filename, Length); - if (Buffer == 0) { - if (ErrorStr) *ErrorStr = "Error reading file '" + Filename + "'!"; - return true; + // See if its the symbol table + if (mbr->isLLVMSymbolTable()) { + parseSymbolTable(mbr->getData(),mbr->getSize()); + FirstFile = At + mbr->getSize(); + if (mbr->getSize() % 2 != 0) + FirstFile++; + } 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); } - - // Parse the archive files we mmap'ped in - bool Result = ReadArchiveBuffer(Filename, Buffer, Length, Objects, ErrorStr); - - // Unmmap the archive... - UnmapFileFromAddressSpace(Buffer, Length); - if (Result) // Free any loaded objects - while (!Objects.empty()) { - delete Objects.back(); - Objects.pop_back(); - } - - return Result; + firstFileOffset = FirstFile - base; +} + +// Open the archive and load just the symbol tables +Archive* +Archive::OpenAndLoadSymbols(const sys::Path& file) { + Archive* result = new Archive(file,true); + + result->loadSymbolTable(); + + return result; +} + +// 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 + ModuleProvider* mp = getBytecodeBufferModuleProvider( + (const unsigned char*) mbr->getData(), mbr->getSize(), + mbr->getPath().get(), 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(const std::set& symbols, + std::set& modules) +{ + for (std::set::const_iterator I=symbols.begin(), + E=symbols.end(); I != E; ++I) { + ModuleProvider* mp = findModuleDefiningSymbol(*I); + if (mp) { + modules.insert(mp); + } + } }