92026fed21
in llvm/ and/or llvm/contrib/clang/ respectively. Approved by: ed (mentor) Approved by: core
631 lines
19 KiB
C++
631 lines
19 KiB
C++
//===-- ArchiveReader.cpp - Read LLVM archive files -------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Builds up standard unix archive files (.a) containing LLVM bitcode.
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//
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//===----------------------------------------------------------------------===//
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#include "ArchiveInternals.h"
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#include "llvm/Bitcode/ReaderWriter.h"
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#include "llvm/Support/MemoryBuffer.h"
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#include "llvm/Module.h"
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#include <cstdlib>
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#include <memory>
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using namespace llvm;
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/// Read a variable-bit-rate encoded unsigned integer
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static inline unsigned readInteger(const char*&At, const char*End) {
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unsigned Shift = 0;
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unsigned Result = 0;
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do {
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if (At == End)
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return Result;
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Result |= (unsigned)((*At++) & 0x7F) << Shift;
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Shift += 7;
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} while (At[-1] & 0x80);
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return Result;
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}
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// Completely parse the Archive's symbol table and populate symTab member var.
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bool
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Archive::parseSymbolTable(const void* data, unsigned size, std::string* error) {
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const char* At = (const char*) data;
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const char* End = At + size;
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while (At < End) {
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unsigned offset = readInteger(At, End);
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if (At == End) {
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if (error)
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*error = "Ran out of data reading vbr_uint for symtab offset!";
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return false;
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}
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unsigned length = readInteger(At, End);
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if (At == End) {
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if (error)
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*error = "Ran out of data reading vbr_uint for symtab length!";
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return false;
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}
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if (At + length > End) {
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if (error)
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*error = "Malformed symbol table: length not consistent with size";
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return false;
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}
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// we don't care if it can't be inserted (duplicate entry)
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symTab.insert(std::make_pair(std::string(At, length), offset));
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At += length;
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}
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symTabSize = size;
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return true;
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}
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// This member parses an ArchiveMemberHeader that is presumed to be pointed to
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// by At. The At pointer is updated to the byte just after the header, which
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// can be variable in size.
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ArchiveMember*
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Archive::parseMemberHeader(const char*& At, const char* End, std::string* error)
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{
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if (At + sizeof(ArchiveMemberHeader) >= End) {
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if (error)
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*error = "Unexpected end of file";
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return 0;
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}
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// Cast archive member header
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ArchiveMemberHeader* Hdr = (ArchiveMemberHeader*)At;
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At += sizeof(ArchiveMemberHeader);
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// Extract the size and determine if the file is
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// compressed or not (negative length).
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int flags = 0;
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int MemberSize = atoi(Hdr->size);
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if (MemberSize < 0) {
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flags |= ArchiveMember::CompressedFlag;
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MemberSize = -MemberSize;
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}
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// Check the size of the member for sanity
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if (At + MemberSize > End) {
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if (error)
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*error = "invalid member length in archive file";
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return 0;
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}
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// Check the member signature
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if (!Hdr->checkSignature()) {
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if (error)
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*error = "invalid file member signature";
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return 0;
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}
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// Convert and check the member name
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// The empty name ( '/' and 15 blanks) is for a foreign (non-LLVM) symbol
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// table. The special name "//" and 14 blanks is for a string table, used
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// for long file names. This library doesn't generate either of those but
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// it will accept them. If the name starts with #1/ and the remainder is
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// digits, then those digits specify the length of the name that is
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// stored immediately following the header. The special name
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// __LLVM_SYM_TAB__ identifies the symbol table for LLVM bitcode.
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// Anything else is a regular, short filename that is terminated with
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// a '/' and blanks.
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std::string pathname;
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switch (Hdr->name[0]) {
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case '#':
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if (Hdr->name[1] == '1' && Hdr->name[2] == '/') {
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if (isdigit(Hdr->name[3])) {
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unsigned len = atoi(&Hdr->name[3]);
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const char *nulp = (const char *)memchr(At, '\0', len);
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pathname.assign(At, nulp != 0 ? (uintptr_t)(nulp - At) : len);
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At += len;
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MemberSize -= len;
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flags |= ArchiveMember::HasLongFilenameFlag;
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} else {
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if (error)
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*error = "invalid long filename";
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return 0;
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}
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} else if (Hdr->name[1] == '_' &&
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(0 == memcmp(Hdr->name, ARFILE_LLVM_SYMTAB_NAME, 16))) {
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// The member is using a long file name (>15 chars) format.
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// This format is standard for 4.4BSD and Mac OSX operating
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// systems. LLVM uses it similarly. In this format, the
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// remainder of the name field (after #1/) specifies the
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// length of the file name which occupy the first bytes of
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// the member's data. The pathname already has the #1/ stripped.
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pathname.assign(ARFILE_LLVM_SYMTAB_NAME);
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flags |= ArchiveMember::LLVMSymbolTableFlag;
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}
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break;
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case '/':
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if (Hdr->name[1]== '/') {
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if (0 == memcmp(Hdr->name, ARFILE_STRTAB_NAME, 16)) {
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pathname.assign(ARFILE_STRTAB_NAME);
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flags |= ArchiveMember::StringTableFlag;
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} else {
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if (error)
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*error = "invalid string table name";
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return 0;
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}
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} else if (Hdr->name[1] == ' ') {
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if (0 == memcmp(Hdr->name, ARFILE_SVR4_SYMTAB_NAME, 16)) {
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pathname.assign(ARFILE_SVR4_SYMTAB_NAME);
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flags |= ArchiveMember::SVR4SymbolTableFlag;
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} else {
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if (error)
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*error = "invalid SVR4 symbol table name";
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return 0;
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}
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} else if (isdigit(Hdr->name[1])) {
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unsigned index = atoi(&Hdr->name[1]);
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if (index < strtab.length()) {
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const char* namep = strtab.c_str() + index;
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const char* endp = strtab.c_str() + strtab.length();
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const char* p = namep;
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const char* last_p = p;
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while (p < endp) {
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if (*p == '\n' && *last_p == '/') {
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pathname.assign(namep, last_p - namep);
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flags |= ArchiveMember::HasLongFilenameFlag;
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break;
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}
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last_p = p;
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p++;
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}
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if (p >= endp) {
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if (error)
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*error = "missing name termiantor in string table";
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return 0;
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}
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} else {
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if (error)
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*error = "name index beyond string table";
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return 0;
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}
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}
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break;
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case '_':
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if (Hdr->name[1] == '_' &&
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(0 == memcmp(Hdr->name, ARFILE_BSD4_SYMTAB_NAME, 16))) {
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pathname.assign(ARFILE_BSD4_SYMTAB_NAME);
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flags |= ArchiveMember::BSD4SymbolTableFlag;
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break;
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}
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/* FALL THROUGH */
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default:
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char* slash = (char*) memchr(Hdr->name, '/', 16);
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if (slash == 0)
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slash = Hdr->name + 16;
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pathname.assign(Hdr->name, slash - Hdr->name);
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break;
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}
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// Determine if this is a bitcode file
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switch (sys::IdentifyFileType(At, 4)) {
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case sys::Bitcode_FileType:
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flags |= ArchiveMember::BitcodeFlag;
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break;
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default:
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flags &= ~ArchiveMember::BitcodeFlag;
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break;
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}
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// Instantiate the ArchiveMember to be filled
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ArchiveMember* member = new ArchiveMember(this);
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// Fill in fields of the ArchiveMember
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member->parent = this;
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member->path.set(pathname);
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member->info.fileSize = MemberSize;
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member->info.modTime.fromEpochTime(atoi(Hdr->date));
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unsigned int mode;
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sscanf(Hdr->mode, "%o", &mode);
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member->info.mode = mode;
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member->info.user = atoi(Hdr->uid);
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member->info.group = atoi(Hdr->gid);
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member->flags = flags;
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member->data = At;
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return member;
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}
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bool
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Archive::checkSignature(std::string* error) {
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// Check the magic string at file's header
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if (mapfile->getBufferSize() < 8 || memcmp(base, ARFILE_MAGIC, 8)) {
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if (error)
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*error = "invalid signature for an archive file";
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return false;
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}
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return true;
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}
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// This function loads the entire archive and fully populates its ilist with
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// the members of the archive file. This is typically used in preparation for
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// editing the contents of the archive.
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bool
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Archive::loadArchive(std::string* error) {
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// Set up parsing
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members.clear();
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symTab.clear();
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const char *At = base;
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const char *End = mapfile->getBufferEnd();
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if (!checkSignature(error))
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return false;
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At += 8; // Skip the magic string.
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bool seenSymbolTable = false;
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bool foundFirstFile = false;
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while (At < End) {
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// parse the member header
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const char* Save = At;
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ArchiveMember* mbr = parseMemberHeader(At, End, error);
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if (!mbr)
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return false;
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// check if this is the foreign symbol table
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if (mbr->isSVR4SymbolTable() || mbr->isBSD4SymbolTable()) {
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// We just save this but don't do anything special
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// with it. It doesn't count as the "first file".
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if (foreignST) {
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// What? Multiple foreign symbol tables? Just chuck it
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// and retain the last one found.
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delete foreignST;
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}
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foreignST = mbr;
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At += mbr->getSize();
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if ((intptr_t(At) & 1) == 1)
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At++;
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} else if (mbr->isStringTable()) {
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// Simply suck the entire string table into a string
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// variable. This will be used to get the names of the
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// members that use the "/ddd" format for their names
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// (SVR4 style long names).
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strtab.assign(At, mbr->getSize());
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At += mbr->getSize();
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if ((intptr_t(At) & 1) == 1)
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At++;
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delete mbr;
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} else if (mbr->isLLVMSymbolTable()) {
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// This is the LLVM symbol table for the archive. If we've seen it
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// already, its an error. Otherwise, parse the symbol table and move on.
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if (seenSymbolTable) {
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if (error)
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*error = "invalid archive: multiple symbol tables";
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return false;
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}
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if (!parseSymbolTable(mbr->getData(), mbr->getSize(), error))
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return false;
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seenSymbolTable = true;
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At += mbr->getSize();
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if ((intptr_t(At) & 1) == 1)
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At++;
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delete mbr; // We don't need this member in the list of members.
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} else {
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// This is just a regular file. If its the first one, save its offset.
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// Otherwise just push it on the list and move on to the next file.
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if (!foundFirstFile) {
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firstFileOffset = Save - base;
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foundFirstFile = true;
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}
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members.push_back(mbr);
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At += mbr->getSize();
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if ((intptr_t(At) & 1) == 1)
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At++;
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}
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}
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return true;
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}
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// Open and completely load the archive file.
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Archive*
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Archive::OpenAndLoad(const sys::Path& file, LLVMContext& C,
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std::string* ErrorMessage) {
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std::auto_ptr<Archive> result ( new Archive(file, C));
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if (result->mapToMemory(ErrorMessage))
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return 0;
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if (!result->loadArchive(ErrorMessage))
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return 0;
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return result.release();
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}
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// Get all the bitcode modules from the archive
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bool
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Archive::getAllModules(std::vector<Module*>& Modules,
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std::string* ErrMessage) {
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for (iterator I=begin(), E=end(); I != E; ++I) {
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if (I->isBitcode()) {
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std::string FullMemberName = archPath.str() +
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"(" + I->getPath().str() + ")";
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MemoryBuffer *Buffer =
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MemoryBuffer::getMemBufferCopy(StringRef(I->getData(), I->getSize()),
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FullMemberName.c_str());
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Module *M = ParseBitcodeFile(Buffer, Context, ErrMessage);
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delete Buffer;
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if (!M)
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return true;
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Modules.push_back(M);
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}
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}
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return false;
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}
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// Load just the symbol table from the archive file
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bool
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Archive::loadSymbolTable(std::string* ErrorMsg) {
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// Set up parsing
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members.clear();
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symTab.clear();
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const char *At = base;
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const char *End = mapfile->getBufferEnd();
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// Make sure we're dealing with an archive
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if (!checkSignature(ErrorMsg))
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return false;
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At += 8; // Skip signature
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// Parse the first file member header
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const char* FirstFile = At;
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ArchiveMember* mbr = parseMemberHeader(At, End, ErrorMsg);
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if (!mbr)
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return false;
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if (mbr->isSVR4SymbolTable() || mbr->isBSD4SymbolTable()) {
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// Skip the foreign symbol table, we don't do anything with it
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At += mbr->getSize();
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if ((intptr_t(At) & 1) == 1)
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At++;
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delete mbr;
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// Read the next one
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FirstFile = At;
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mbr = parseMemberHeader(At, End, ErrorMsg);
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if (!mbr) {
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delete mbr;
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return false;
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}
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}
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if (mbr->isStringTable()) {
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// Process the string table entry
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strtab.assign((const char*)mbr->getData(), mbr->getSize());
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At += mbr->getSize();
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if ((intptr_t(At) & 1) == 1)
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At++;
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delete mbr;
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// Get the next one
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FirstFile = At;
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mbr = parseMemberHeader(At, End, ErrorMsg);
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if (!mbr) {
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delete mbr;
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return false;
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}
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}
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// See if its the symbol table
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if (mbr->isLLVMSymbolTable()) {
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if (!parseSymbolTable(mbr->getData(), mbr->getSize(), ErrorMsg)) {
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delete mbr;
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return false;
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}
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At += mbr->getSize();
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if ((intptr_t(At) & 1) == 1)
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At++;
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delete mbr;
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// Can't be any more symtab headers so just advance
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FirstFile = At;
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} else {
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// There's no symbol table in the file. We have to rebuild it from scratch
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// because the intent of this method is to get the symbol table loaded so
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// it can be searched efficiently.
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// Add the member to the members list
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members.push_back(mbr);
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}
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firstFileOffset = FirstFile - base;
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return true;
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}
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// Open the archive and load just the symbol tables
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Archive* Archive::OpenAndLoadSymbols(const sys::Path& file,
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LLVMContext& C,
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std::string* ErrorMessage) {
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std::auto_ptr<Archive> result ( new Archive(file, C) );
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if (result->mapToMemory(ErrorMessage))
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return 0;
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if (!result->loadSymbolTable(ErrorMessage))
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return 0;
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return result.release();
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}
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// Look up one symbol in the symbol table and return the module that defines
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// that symbol.
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Module*
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Archive::findModuleDefiningSymbol(const std::string& symbol,
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std::string* ErrMsg) {
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SymTabType::iterator SI = symTab.find(symbol);
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if (SI == symTab.end())
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return 0;
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// The symbol table was previously constructed assuming that the members were
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// written without the symbol table header. Because VBR encoding is used, the
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// values could not be adjusted to account for the offset of the symbol table
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// because that could affect the size of the symbol table due to VBR encoding.
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// We now have to account for this by adjusting the offset by the size of the
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// symbol table and its header.
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unsigned fileOffset =
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SI->second + // offset in symbol-table-less file
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firstFileOffset; // add offset to first "real" file in archive
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// See if the module is already loaded
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ModuleMap::iterator MI = modules.find(fileOffset);
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if (MI != modules.end())
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return MI->second.first;
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// Module hasn't been loaded yet, we need to load it
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const char* modptr = base + fileOffset;
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ArchiveMember* mbr = parseMemberHeader(modptr, mapfile->getBufferEnd(),
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ErrMsg);
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if (!mbr)
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return 0;
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// Now, load the bitcode module to get the Module.
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std::string FullMemberName = archPath.str() + "(" +
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mbr->getPath().str() + ")";
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MemoryBuffer *Buffer =
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MemoryBuffer::getMemBufferCopy(StringRef(mbr->getData(), mbr->getSize()),
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FullMemberName.c_str());
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Module *m = getLazyBitcodeModule(Buffer, Context, ErrMsg);
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if (!m)
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return 0;
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modules.insert(std::make_pair(fileOffset, std::make_pair(m, mbr)));
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return m;
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}
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// Look up multiple symbols in the symbol table and return a set of
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// Modules that define those symbols.
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bool
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Archive::findModulesDefiningSymbols(std::set<std::string>& symbols,
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std::set<Module*>& result,
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std::string* error) {
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if (!mapfile || !base) {
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if (error)
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*error = "Empty archive invalid for finding modules defining symbols";
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return false;
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}
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if (symTab.empty()) {
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// We don't have a symbol table, so we must build it now but lets also
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// make sure that we populate the modules table as we do this to ensure
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// that we don't load them twice when findModuleDefiningSymbol is called
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// below.
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// Get a pointer to the first file
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const char* At = base + firstFileOffset;
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const char* End = mapfile->getBufferEnd();
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|
|
|
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.
|
|
|
|
for (std::set<std::string>::iterator I=symbols.begin(),
|
|
E=symbols.end(); I != E;) {
|
|
// See if this symbol exists
|
|
Module* m = findModuleDefiningSymbol(*I,error);
|
|
if (m) {
|
|
// The symbol exists, insert the Module into our result, duplicates will
|
|
// be ignored.
|
|
result.insert(m);
|
|
|
|
// Remove the symbol now that its been resolved, being careful to
|
|
// post-increment the iterator.
|
|
symbols.erase(I++);
|
|
} else {
|
|
++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;
|
|
}
|