From 87f90729d699b23843e3f87b2565e9caac395e7b Mon Sep 17 00:00:00 2001 From: Reid Spencer Date: Tue, 16 Nov 2004 06:47:30 +0000 Subject: Per code review:\ * Make the numVbrBytes function more efficient and better documented \ * Fix a bug in name truncation \ * Add comments before functions \ * Get rid of functions that are now inlined into the header \ * Do not have Archive doing symbol table printing \ * Put assert comments into the assert so they print out \ * Make sure foreign symbol tables are written git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17884 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Archive/ArchiveWriter.cpp | 90 ++++++++++++++++++++++--------------------- 1 file changed, 46 insertions(+), 44 deletions(-) (limited to 'lib/Archive/ArchiveWriter.cpp') diff --git a/lib/Archive/ArchiveWriter.cpp b/lib/Archive/ArchiveWriter.cpp index fa4d9e64fde..e737a040945 100644 --- a/lib/Archive/ArchiveWriter.cpp +++ b/lib/Archive/ArchiveWriter.cpp @@ -22,8 +22,6 @@ using namespace llvm; -namespace { - // Write an integer using variable bit rate encoding. This saves a few bytes // per entry in the symbol table. inline void writeInteger(unsigned num, std::ofstream& ARFile) { @@ -43,17 +41,24 @@ inline void writeInteger(unsigned num, std::ofstream& ARFile) { // Compute how many bytes are taken by a given VBR encoded value. This is needed // to pre-compute the size of the symbol table. inline unsigned numVbrBytes(unsigned num) { - if (num < 128) // 2^7 - return 1; - if (num < 16384) // 2^14 - return 2; - if (num < 2097152) // 2^21 + + // Note that the following nested ifs are somewhat equivalent to a binary + // search. We split it in half by comparing against 2^14 first. This allows + // most reasonable values to be done in 2 comparisons instead of 1 for + // small ones and four for large ones. We expect this to access file offsets + // in the 2^10 to 2^24 range and symbol lengths in the 2^0 to 2^8 rnage, + // so this approach is reasonable. + if (num < 1<<14) + if (num < 1<<7) + return 1; + else + return 2; + if (num < 1<<21) return 3; - if (num < 268435456) // 2^28 - return 4; - return 5; // anything >= 2^28 takes 5 bytes -} + if (num < 1<<28) + return 4; + return 5; // anything >= 2^28 takes 5 bytes } // Create an empty archive. @@ -63,6 +68,12 @@ Archive::CreateEmpty(const sys::Path& FilePath ) { return result; } +// Fill the ArchiveMemberHeader with the information from a member. If +// TruncateNames is true, names are flattened to 15 chars or less. The sz field +// is provided here instead of coming from the mbr because the member might be +// stored compressed and the compressed size is not the ArchiveMember's size. +// Furthermore compressed files have negative size fields to identify them as +// compressed. bool Archive::fillHeader(const ArchiveMember &mbr, ArchiveMemberHeader& hdr, int sz, bool TruncateNames) const { @@ -78,7 +89,7 @@ Archive::fillHeader(const ArchiveMember &mbr, ArchiveMemberHeader& hdr, memcpy(hdr.gid,buffer,6); // Set the size field - if (sz < 0 ) { + if (sz < 0) { buffer[0] = '-'; sprintf(&buffer[1],"%-9u",(unsigned)-sz); } else { @@ -108,9 +119,9 @@ Archive::fillHeader(const ArchiveMember &mbr, ArchiveMemberHeader& hdr, nm += slashpos + 1; len -= slashpos +1; } - if (len >15) + if (len > 15) len = 15; - mbrPath.copy(hdr.name,len); + memcpy(hdr.name,nm,len); hdr.name[len] = '/'; } else if (mbrPath.length() < 16 && mbrPath.find('/') == std::string::npos) { mbrPath.copy(hdr.name,mbrPath.length()); @@ -124,6 +135,8 @@ Archive::fillHeader(const ArchiveMember &mbr, ArchiveMemberHeader& hdr, return writeLongName; } +// Insert a file into the archive before some other member. This also takes care +// of extracting the necessary flags and information from the file. void Archive::addFileBefore(const sys::Path& filePath, iterator where) { assert(filePath.exists() && "Can't add a non-existent file"); @@ -156,19 +169,7 @@ Archive::addFileBefore(const sys::Path& filePath, iterator where) { members.insert(where,mbr); } -void -Archive::moveMemberBefore(iterator target, iterator where) { - assert(target != end() && "Target iterator for moveMemberBefore is invalid"); - ArchiveMember* mbr = members.remove(target); - members.insert(where, mbr); -} - -void -Archive::remove(iterator target) { - assert(target != end() && "Target iterator for remove is invalid"); - ArchiveMember* mbr = members.remove(target); - delete mbr; -} +// Write one member out to the file. void Archive::writeMember( const ArchiveMember& member, @@ -291,8 +292,9 @@ Archive::writeMember( } } +// Write out the LLVM symbol table as an archive member to the file. void -Archive::writeSymbolTable(std::ofstream& ARFile,bool PrintSymTab ) { +Archive::writeSymbolTable(std::ofstream& ARFile) { // Construct the symbol table's header ArchiveMemberHeader Hdr; @@ -311,10 +313,6 @@ Archive::writeSymbolTable(std::ofstream& ARFile,bool PrintSymTab ) { // Save the starting position of the symbol tables data content. unsigned startpos = ARFile.tellp(); - // Print the symbol table header if we're supposed to - if (PrintSymTab) - std::cout << "Symbol Table:\n"; - // Write out the symbols sequentially for ( Archive::SymTabType::iterator I = symTab.begin(), E = symTab.end(); I != E; ++I) @@ -325,13 +323,6 @@ Archive::writeSymbolTable(std::ofstream& ARFile,bool PrintSymTab ) { writeInteger(I->first.length(), ARFile); // Write out the symbol ARFile.write(I->first.data(), I->first.length()); - - // Print this entry to std::cout if we should - if (PrintSymTab) { - unsigned filepos = I->second + symTabSize + sizeof(ArchiveMemberHeader) + - (symTabSize % 2 != 0) + 8; - std::cout << " " << std::setw(9) << filepos << "\t" << I->first << "\n"; - } } // Now that we're done with the symbol table, get the ending file position @@ -346,13 +337,17 @@ Archive::writeSymbolTable(std::ofstream& ARFile,bool PrintSymTab ) { ARFile << ARFILE_PAD; } +// Write the entire archive to the file specified when the archive was created. +// This writes to a temporary file first. Options are for creating a symbol +// table, flattening the file names (no directories, 15 chars max) and +// compressing each archive member. void -Archive::writeToDisk(bool CreateSymbolTable, bool TruncateNames, - bool Compress, bool PrintSymTab) { +Archive::writeToDisk(bool CreateSymbolTable, bool TruncateNames, bool Compress){ // Make sure they haven't opened up the file, not loaded it, // but are now trying to write it which would wipe out the file. - assert(!(members.empty() && mapfile->size() > 8)); + assert(!(members.empty() && mapfile->size() > 8) && + "Can't write an archive not opened for writing"); // Create a temporary file to store the archive in sys::Path TmpArchive = archPath; @@ -396,6 +391,8 @@ Archive::writeToDisk(bool CreateSymbolTable, bool TruncateNames, // ensure compatibility with other archivers we need to put the symbol // table first in the file. Unfortunately, this means mapping the file // we just wrote back in and copying it to the destination file. + + // Map in the archive we just wrote. sys::MappedFile arch(TmpArchive); const char* base = (const char*) arch.map(); @@ -408,8 +405,13 @@ Archive::writeToDisk(bool CreateSymbolTable, bool TruncateNames, // Write the file magic number FinalFile << ARFILE_MAGIC; - // Put out the symbol table - writeSymbolTable(FinalFile,PrintSymTab); + // If there is a foreign symbol table, put it into the file now. + if (foreignST) { + writeMember(*foreignST, FinalFile, false, false, false); + } + + // Put out the LLVM symbol table now. + writeSymbolTable(FinalFile); // Copy the temporary file contents being sure to skip the file's magic // number. -- cgit v1.2.3