mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-27 13:30:05 +00:00
6ff7240a5c
file to become corrupted due to interactions between mmap'd memory segments and file descriptors closing. The problem is completely avoiding by using a third temporary file. Patch provided by Evan Jones git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24527 91177308-0d34-0410-b5e6-96231b3b80d8
483 lines
16 KiB
C++
483 lines
16 KiB
C++
//===-- ArchiveWriter.cpp - Write LLVM archive files ----------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by Reid Spencer and is distributed under the
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// University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Builds up an LLVM archive file (.a) containing LLVM bytecode.
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//
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//===----------------------------------------------------------------------===//
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#include "ArchiveInternals.h"
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#include "llvm/Bytecode/Reader.h"
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#include "llvm/Support/Compressor.h"
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#include "llvm/System/Signals.h"
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#include "llvm/System/Process.h"
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#include <fstream>
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#include <iostream>
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#include <iomanip>
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using namespace llvm;
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// Write an integer using variable bit rate encoding. This saves a few bytes
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// per entry in the symbol table.
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inline void writeInteger(unsigned num, std::ofstream& ARFile) {
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while (1) {
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if (num < 0x80) { // done?
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ARFile << (unsigned char)num;
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return;
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}
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// Nope, we are bigger than a character, output the next 7 bits and set the
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// high bit to say that there is more coming...
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ARFile << (unsigned char)(0x80 | ((unsigned char)num & 0x7F));
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num >>= 7; // Shift out 7 bits now...
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}
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}
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// Compute how many bytes are taken by a given VBR encoded value. This is needed
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// to pre-compute the size of the symbol table.
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inline unsigned numVbrBytes(unsigned num) {
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// Note that the following nested ifs are somewhat equivalent to a binary
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// search. We split it in half by comparing against 2^14 first. This allows
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// most reasonable values to be done in 2 comparisons instead of 1 for
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// small ones and four for large ones. We expect this to access file offsets
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// in the 2^10 to 2^24 range and symbol lengths in the 2^0 to 2^8 range,
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// so this approach is reasonable.
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if (num < 1<<14)
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if (num < 1<<7)
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return 1;
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else
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return 2;
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if (num < 1<<21)
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return 3;
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if (num < 1<<28)
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return 4;
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return 5; // anything >= 2^28 takes 5 bytes
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}
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// Create an empty archive.
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Archive*
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Archive::CreateEmpty(const sys::Path& FilePath ) {
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Archive* result = new Archive(FilePath,false);
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return result;
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}
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// Fill the ArchiveMemberHeader with the information from a member. If
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// TruncateNames is true, names are flattened to 15 chars or less. The sz field
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// is provided here instead of coming from the mbr because the member might be
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// stored compressed and the compressed size is not the ArchiveMember's size.
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// Furthermore compressed files have negative size fields to identify them as
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// compressed.
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bool
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Archive::fillHeader(const ArchiveMember &mbr, ArchiveMemberHeader& hdr,
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int sz, bool TruncateNames) const {
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// Set the permissions mode, uid and gid
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hdr.init();
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char buffer[32];
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sprintf(buffer, "%-8o", mbr.getMode());
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memcpy(hdr.mode,buffer,8);
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sprintf(buffer, "%-6u", mbr.getUser());
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memcpy(hdr.uid,buffer,6);
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sprintf(buffer, "%-6u", mbr.getGroup());
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memcpy(hdr.gid,buffer,6);
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// Set the last modification date
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uint64_t secondsSinceEpoch = mbr.getModTime().toEpochTime();
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sprintf(buffer,"%-12u", unsigned(secondsSinceEpoch));
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memcpy(hdr.date,buffer,12);
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// Get rid of trailing blanks in the name
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std::string mbrPath = mbr.getPath().toString();
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size_t mbrLen = mbrPath.length();
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while (mbrLen > 0 && mbrPath[mbrLen-1] == ' ') {
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mbrPath.erase(mbrLen-1,1);
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mbrLen--;
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}
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// Set the name field in one of its various flavors.
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bool writeLongName = false;
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if (mbr.isStringTable()) {
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memcpy(hdr.name,ARFILE_STRTAB_NAME,16);
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} else if (mbr.isSVR4SymbolTable()) {
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memcpy(hdr.name,ARFILE_SVR4_SYMTAB_NAME,16);
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} else if (mbr.isBSD4SymbolTable()) {
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memcpy(hdr.name,ARFILE_BSD4_SYMTAB_NAME,16);
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} else if (mbr.isLLVMSymbolTable()) {
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memcpy(hdr.name,ARFILE_LLVM_SYMTAB_NAME,16);
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} else if (TruncateNames) {
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const char* nm = mbrPath.c_str();
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unsigned len = mbrPath.length();
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size_t slashpos = mbrPath.rfind('/');
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if (slashpos != std::string::npos) {
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nm += slashpos + 1;
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len -= slashpos +1;
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}
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if (len > 15)
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len = 15;
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memcpy(hdr.name,nm,len);
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hdr.name[len] = '/';
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} else if (mbrPath.length() < 16 && mbrPath.find('/') == std::string::npos) {
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memcpy(hdr.name,mbrPath.c_str(),mbrPath.length());
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hdr.name[mbrPath.length()] = '/';
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} else {
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std::string nm = "#1/";
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nm += utostr(mbrPath.length());
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memcpy(hdr.name,nm.data(),nm.length());
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if (sz < 0)
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sz -= mbrPath.length();
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else
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sz += mbrPath.length();
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writeLongName = true;
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}
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// Set the size field
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if (sz < 0) {
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buffer[0] = '-';
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sprintf(&buffer[1],"%-9u",(unsigned)-sz);
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} else {
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sprintf(buffer, "%-10u", (unsigned)sz);
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}
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memcpy(hdr.size,buffer,10);
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return writeLongName;
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}
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// Insert a file into the archive before some other member. This also takes care
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// of extracting the necessary flags and information from the file.
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void
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Archive::addFileBefore(const sys::Path& filePath, iterator where) {
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assert(filePath.exists() && "Can't add a non-existent file");
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ArchiveMember* mbr = new ArchiveMember(this);
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mbr->data = 0;
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mbr->path = filePath;
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mbr->path.getStatusInfo(mbr->info);
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unsigned flags = 0;
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bool hasSlash = filePath.toString().find('/') != std::string::npos;
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if (hasSlash)
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flags |= ArchiveMember::HasPathFlag;
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if (hasSlash || filePath.toString().length() > 15)
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flags |= ArchiveMember::HasLongFilenameFlag;
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std::string magic;
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mbr->path.getMagicNumber(magic,4);
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switch (sys::IdentifyFileType(magic.c_str(),4)) {
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case sys::BytecodeFileType:
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flags |= ArchiveMember::BytecodeFlag;
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break;
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case sys::CompressedBytecodeFileType:
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flags |= ArchiveMember::CompressedBytecodeFlag;
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break;
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default:
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break;
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}
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mbr->flags = flags;
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members.insert(where,mbr);
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}
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// Write one member out to the file.
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void
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Archive::writeMember(
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const ArchiveMember& member,
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std::ofstream& ARFile,
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bool CreateSymbolTable,
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bool TruncateNames,
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bool ShouldCompress
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) {
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unsigned filepos = ARFile.tellp();
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filepos -= 8;
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// Get the data and its size either from the
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// member's in-memory data or directly from the file.
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size_t fSize = member.getSize();
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const char* data = (const char*)member.getData();
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sys::MappedFile* mFile = 0;
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if (!data) {
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mFile = new sys::MappedFile(member.getPath());
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data = (const char*) mFile->map();
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fSize = mFile->size();
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}
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// Now that we have the data in memory, update the
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// symbol table if its a bytecode file.
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if (CreateSymbolTable &&
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(member.isBytecode() || member.isCompressedBytecode())) {
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std::vector<std::string> symbols;
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std::string FullMemberName = archPath.toString() + "(" +
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member.getPath().toString()
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+ ")";
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ModuleProvider* MP = GetBytecodeSymbols(
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(const unsigned char*)data,fSize,FullMemberName, symbols);
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// If the bytecode parsed successfully
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if ( MP ) {
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for (std::vector<std::string>::iterator SI = symbols.begin(),
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SE = symbols.end(); SI != SE; ++SI) {
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std::pair<SymTabType::iterator,bool> Res =
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symTab.insert(std::make_pair(*SI,filepos));
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if (Res.second) {
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symTabSize += SI->length() +
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numVbrBytes(SI->length()) +
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numVbrBytes(filepos);
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}
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}
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// We don't need this module any more.
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delete MP;
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} else {
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throw std::string("Can't parse bytecode member: ") +
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member.getPath().toString();
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}
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}
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// Determine if we actually should compress this member
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bool willCompress =
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(ShouldCompress &&
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!member.isCompressed() &&
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!member.isCompressedBytecode() &&
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!member.isLLVMSymbolTable() &&
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!member.isSVR4SymbolTable() &&
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!member.isBSD4SymbolTable());
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// Perform the compression. Note that if the file is uncompressed bytecode
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// then we turn the file into compressed bytecode rather than treating it as
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// compressed data. This is necessary since it allows us to determine that the
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// file contains bytecode instead of looking like a regular compressed data
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// member. A compressed bytecode file has its content compressed but has a
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// magic number of "llvc". This acounts for the +/-4 arithmetic in the code
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// below.
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int hdrSize;
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if (willCompress) {
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char* output = 0;
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if (member.isBytecode()) {
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data +=4;
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fSize -= 4;
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}
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fSize = Compressor::compressToNewBuffer(data,fSize,output);
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data = output;
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if (member.isBytecode())
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hdrSize = -fSize-4;
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else
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hdrSize = -fSize;
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} else {
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hdrSize = fSize;
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}
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// Compute the fields of the header
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ArchiveMemberHeader Hdr;
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bool writeLongName = fillHeader(member,Hdr,hdrSize,TruncateNames);
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// Write header to archive file
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ARFile.write((char*)&Hdr, sizeof(Hdr));
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// Write the long filename if its long
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if (writeLongName) {
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ARFile.write(member.getPath().toString().data(),
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member.getPath().toString().length());
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}
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// Make sure we write the compressed bytecode magic number if we should.
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if (willCompress && member.isBytecode())
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ARFile.write("llvc",4);
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// Write the (possibly compressed) member's content to the file.
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ARFile.write(data,fSize);
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// Make sure the member is an even length
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if ((ARFile.tellp() & 1) == 1)
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ARFile << ARFILE_PAD;
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// Free the compressed data, if necessary
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if (willCompress) {
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free((void*)data);
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}
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// Close the mapped file if it was opened
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if (mFile != 0) {
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mFile->close();
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delete mFile;
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}
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}
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// Write out the LLVM symbol table as an archive member to the file.
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void
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Archive::writeSymbolTable(std::ofstream& ARFile) {
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// Construct the symbol table's header
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ArchiveMemberHeader Hdr;
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Hdr.init();
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memcpy(Hdr.name,ARFILE_LLVM_SYMTAB_NAME,16);
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uint64_t secondsSinceEpoch = sys::TimeValue::now().toEpochTime();
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char buffer[32];
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sprintf(buffer, "%-8o", 0644);
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memcpy(Hdr.mode,buffer,8);
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sprintf(buffer, "%-6u", sys::Process::GetCurrentUserId());
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memcpy(Hdr.uid,buffer,6);
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sprintf(buffer, "%-6u", sys::Process::GetCurrentGroupId());
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memcpy(Hdr.gid,buffer,6);
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sprintf(buffer,"%-12u", unsigned(secondsSinceEpoch));
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memcpy(Hdr.date,buffer,12);
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sprintf(buffer,"%-10u",symTabSize);
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memcpy(Hdr.size,buffer,10);
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// Write the header
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ARFile.write((char*)&Hdr, sizeof(Hdr));
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// Save the starting position of the symbol tables data content.
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unsigned startpos = ARFile.tellp();
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// Write out the symbols sequentially
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for ( Archive::SymTabType::iterator I = symTab.begin(), E = symTab.end();
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I != E; ++I)
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{
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// Write out the file index
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writeInteger(I->second, ARFile);
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// Write out the length of the symbol
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writeInteger(I->first.length(), ARFile);
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// Write out the symbol
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ARFile.write(I->first.data(), I->first.length());
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}
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// Now that we're done with the symbol table, get the ending file position
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unsigned endpos = ARFile.tellp();
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// Make sure that the amount we wrote is what we pre-computed. This is
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// critical for file integrity purposes.
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assert(endpos - startpos == symTabSize && "Invalid symTabSize computation");
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// Make sure the symbol table is even sized
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if (symTabSize % 2 != 0 )
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ARFile << ARFILE_PAD;
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}
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// Write the entire archive to the file specified when the archive was created.
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// This writes to a temporary file first. Options are for creating a symbol
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// table, flattening the file names (no directories, 15 chars max) and
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// compressing each archive member.
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void
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Archive::writeToDisk(bool CreateSymbolTable, bool TruncateNames, bool Compress){
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// Make sure they haven't opened up the file, not loaded it,
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// but are now trying to write it which would wipe out the file.
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assert(!(members.empty() && mapfile->size() > 8) &&
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"Can't write an archive not opened for writing");
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// Create a temporary file to store the archive in
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sys::Path TmpArchive = archPath;
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TmpArchive.createTemporaryFileOnDisk();
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// Make sure the temporary gets removed if we crash
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sys::RemoveFileOnSignal(TmpArchive);
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// Ensure we can remove the temporary even in the face of an exception
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try {
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// Create archive file for output.
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std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
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std::ios::binary;
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std::ofstream ArchiveFile(TmpArchive.c_str(), io_mode);
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// Check for errors opening or creating archive file.
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if ( !ArchiveFile.is_open() || ArchiveFile.bad() ) {
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throw std::string("Error opening archive file: ") + archPath.toString();
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}
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// If we're creating a symbol table, reset it now
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if (CreateSymbolTable) {
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symTabSize = 0;
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symTab.clear();
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}
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// Write magic string to archive.
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ArchiveFile << ARFILE_MAGIC;
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// Loop over all member files, and write them out. Note that this also
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// builds the symbol table, symTab.
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for ( MembersList::iterator I = begin(), E = end(); I != E; ++I) {
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writeMember(*I,ArchiveFile,CreateSymbolTable,TruncateNames,Compress);
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}
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// Close archive file.
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ArchiveFile.close();
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// Write the symbol table
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if (CreateSymbolTable) {
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// At this point we have written a file that is a legal archive but it
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// doesn't have a symbol table in it. To aid in faster reading and to
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// ensure compatibility with other archivers we need to put the symbol
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// table first in the file. Unfortunately, this means mapping the file
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// we just wrote back in and copying it to the destination file.
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// Map in the archive we just wrote.
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sys::MappedFile arch(TmpArchive);
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const char* base = (const char*) arch.map();
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// Open another temporary file in order to avoid invalidating the mmapped data
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sys::Path FinalFilePath = archPath;
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FinalFilePath.createTemporaryFileOnDisk();
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sys::RemoveFileOnSignal(FinalFilePath);
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try {
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std::ofstream FinalFile(FinalFilePath.c_str(), io_mode);
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if ( !FinalFile.is_open() || FinalFile.bad() ) {
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throw std::string("Error opening archive file: ") + FinalFilePath.toString();
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}
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// Write the file magic number
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FinalFile << ARFILE_MAGIC;
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// If there is a foreign symbol table, put it into the file now. Most
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// ar(1) implementations require the symbol table to be first but llvm-ar
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// can deal with it being after a foreign symbol table. This ensures
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// compatibility with other ar(1) implementations as well as allowing the
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// archive to store both native .o and LLVM .bc files, both indexed.
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if (foreignST) {
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writeMember(*foreignST, FinalFile, false, false, false);
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}
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// Put out the LLVM symbol table now.
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writeSymbolTable(FinalFile);
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// Copy the temporary file contents being sure to skip the file's magic
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// number.
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FinalFile.write(base + sizeof(ARFILE_MAGIC)-1,
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arch.size()-sizeof(ARFILE_MAGIC)+1);
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// Close up shop
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FinalFile.close();
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arch.close();
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// Move the final file over top of TmpArchive
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FinalFilePath.renamePathOnDisk(TmpArchive);
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} catch (...) {
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// Make sure we clean up.
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if (FinalFilePath.exists())
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FinalFilePath.eraseFromDisk();
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throw;
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}
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}
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// Before we replace the actual archive, we need to forget all the
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// members, since they point to data in that old archive. We need to do
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// we cannot replace an open file on Windows.
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cleanUpMemory();
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TmpArchive.renamePathOnDisk(archPath);
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} catch (...) {
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// Make sure we clean up.
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if (TmpArchive.exists())
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TmpArchive.eraseFromDisk();
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throw;
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}
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}
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