mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-10-31 09:11:13 +00:00
a2b2dc9795
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8058 91177308-0d34-0410-b5e6-96231b3b80d8
453 lines
17 KiB
C++
453 lines
17 KiB
C++
//===- gccld.cpp - LLVM 'ld' compatible linker ----------------------------===//
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//
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// This utility is intended to be compatible with GCC, and follows standard
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// system 'ld' conventions. As such, the default output file is ./a.out.
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// Additionally, this program outputs a shell script that is used to invoke LLI
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// to execute the program. In this manner, the generated executable (a.out for
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// example), is directly executable, whereas the bytecode file actually lives in
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// the a.out.bc file generated by this program. Also, Force is on by default.
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//
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// Note that if someone (or a script) deletes the executable program generated,
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// the .bc file will be left around. Considering that this is a temporary hack,
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// I'm not too worried about this.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Utils/Linker.h"
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#include "llvm/Module.h"
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#include "llvm/PassManager.h"
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#include "llvm/Bytecode/Reader.h"
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#include "llvm/Bytecode/WriteBytecodePass.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Transforms/IPO.h"
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#include "llvm/Transforms/Scalar.h"
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#include "Support/CommandLine.h"
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#include "Support/Signals.h"
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#include <fstream>
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#include <memory>
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#include <set>
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#include <algorithm>
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#include <sys/types.h> // For FileExists
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#include <sys/stat.h>
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namespace {
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cl::list<std::string>
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InputFilenames(cl::Positional, cl::desc("<input bytecode files>"),
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cl::OneOrMore);
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cl::opt<std::string>
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OutputFilename("o", cl::desc("Override output filename"), cl::init("a.out"),
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cl::value_desc("filename"));
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cl::opt<bool>
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Verbose("v", cl::desc("Print information about actions taken"));
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cl::list<std::string>
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LibPaths("L", cl::desc("Specify a library search path"), cl::Prefix,
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cl::value_desc("directory"));
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cl::list<std::string>
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Libraries("l", cl::desc("Specify libraries to link to"), cl::Prefix,
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cl::value_desc("library prefix"));
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cl::opt<bool>
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Strip("s", cl::desc("Strip symbol info from executable"));
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cl::opt<bool>
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NoInternalize("disable-internalize",
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cl::desc("Do not mark all symbols as internal"));
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static cl::alias
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ExportDynamic("export-dynamic", cl::desc("Alias for -disable-internalize"),
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cl::aliasopt(NoInternalize));
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cl::opt<bool>
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LinkAsLibrary("link-as-library", cl::desc("Link the .bc files together as a"
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" library, not an executable"));
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// Compatibility options that are ignored, but support by LD
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cl::opt<std::string>
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CO3("soname", cl::Hidden, cl::desc("Compatibility option: ignored"));
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cl::opt<std::string>
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CO4("version-script", cl::Hidden, cl::desc("Compatibility option: ignored"));
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cl::opt<bool>
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CO5("eh-frame-hdr", cl::Hidden, cl::desc("Compatibility option: ignored"));
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cl::opt<bool>
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CO6("r", cl::Hidden, cl::desc("Compatibility option: ignored"));
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}
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// FileExists - Return true if the specified string is an openable file...
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static inline bool FileExists(const std::string &FN) {
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struct stat StatBuf;
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return stat(FN.c_str(), &StatBuf) != -1;
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}
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// LoadObject - Read the specified "object file", which should not search the
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// library path to find it.
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static inline std::auto_ptr<Module> LoadObject(std::string FN,
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std::string &OutErrorMessage) {
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if (Verbose) std::cerr << "Loading '" << FN << "'\n";
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if (!FileExists(FN)) {
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// Attempt to load from the LLVM_LIB_SEARCH_PATH directory... if we would
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// otherwise fail. This is used to locate objects like crtend.o.
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//
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char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH");
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if (SearchPath && FileExists(std::string(SearchPath)+"/"+FN))
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FN = std::string(SearchPath)+"/"+FN;
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else {
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OutErrorMessage = "could not find input file '" + FN + "'!";
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return std::auto_ptr<Module>();
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}
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}
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std::string ErrorMessage;
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Module *Result = ParseBytecodeFile(FN, &ErrorMessage);
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if (Result) return std::auto_ptr<Module>(Result);
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OutErrorMessage = "Bytecode file '" + FN + "' corrupt!";
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if (ErrorMessage.size()) OutErrorMessage += ": " + ErrorMessage;
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return std::auto_ptr<Module>();
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}
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static Module *LoadSingleLibraryObject(const std::string &Filename) {
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std::string ErrorMessage;
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std::auto_ptr<Module> M = LoadObject(Filename, ErrorMessage);
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if (M.get() == 0 && Verbose) {
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std::cerr << "Error loading '" + Filename + "'";
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if (!ErrorMessage.empty()) std::cerr << ": " << ErrorMessage;
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std::cerr << "\n";
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}
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return M.release();
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}
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// IsArchive - Returns true iff FILENAME appears to be the name of an ar
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// archive file. It determines this by checking the magic string at the
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// beginning of the file.
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static bool IsArchive(const std::string &filename) {
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std::string ArchiveMagic("!<arch>\012");
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char buf[1 + ArchiveMagic.size()];
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std::ifstream f(filename.c_str());
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f.read(buf, ArchiveMagic.size());
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buf[ArchiveMagic.size()] = '\0';
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return ArchiveMagic == buf;
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}
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// LoadLibraryExactName - This looks for a file with a known name and tries to
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// load it, similarly to LoadLibraryFromDirectory().
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static inline bool LoadLibraryExactName(const std::string &FileName,
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std::vector<Module*> &Objects, bool &isArchive) {
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if (Verbose) std::cerr << " Considering '" << FileName << "'\n";
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if (FileExists(FileName)) {
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if (IsArchive(FileName)) {
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std::string ErrorMessage;
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if (Verbose) std::cerr << " Loading '" << FileName << "'\n";
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if (!ReadArchiveFile(FileName, Objects, &ErrorMessage)) {
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isArchive = true;
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return false; // Success!
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}
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if (Verbose) {
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std::cerr << " Error loading archive '" + FileName + "'";
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if (!ErrorMessage.empty()) std::cerr << ": " << ErrorMessage;
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std::cerr << "\n";
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}
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} else {
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if (Module *M = LoadSingleLibraryObject(FileName)) {
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isArchive = false;
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Objects.push_back(M);
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return false;
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}
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}
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}
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return true;
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}
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// LoadLibrary - Try to load a library named LIBNAME that contains
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// LLVM bytecode. If SEARCH is true, then search for a file named
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// libLIBNAME.{a,so,bc} in the current library search path. Otherwise,
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// assume LIBNAME is the real name of the library file. This method puts
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// the loaded modules into the Objects list, and sets isArchive to true if
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// a .a file was loaded. It returns true if no library is found or if an
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// error occurs; otherwise it returns false.
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//
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static inline bool LoadLibrary(const std::string &LibName,
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std::vector<Module*> &Objects, bool &isArchive,
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bool search, std::string &ErrorMessage) {
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if (search) {
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// First, try the current directory. Then, iterate over the
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// directories in LibPaths, looking for a suitable match for LibName
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// in each one.
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for (unsigned NextLibPathIdx = 0; NextLibPathIdx != LibPaths.size();
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++NextLibPathIdx) {
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std::string Directory = LibPaths[NextLibPathIdx] + "/";
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if (!LoadLibraryExactName(Directory + "lib" + LibName + ".a",
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Objects, isArchive))
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return false;
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if (!LoadLibraryExactName(Directory + "lib" + LibName + ".so",
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Objects, isArchive))
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return false;
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if (!LoadLibraryExactName(Directory + "lib" + LibName + ".bc",
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Objects, isArchive))
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return false;
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}
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} else {
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// If they said no searching, then assume LibName is the real name.
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if (!LoadLibraryExactName(LibName, Objects, isArchive))
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return false;
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}
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ErrorMessage = "error linking library '-l" + LibName+ "': library not found!";
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return true;
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}
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static void GetAllDefinedSymbols(Module *M,
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std::set<std::string> &DefinedSymbols) {
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for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
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if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
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DefinedSymbols.insert(I->getName());
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for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
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if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
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DefinedSymbols.insert(I->getName());
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}
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// GetAllUndefinedSymbols - This calculates the set of undefined symbols that
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// still exist in an LLVM module. This is a bit tricky because there may be two
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// symbols with the same name, but different LLVM types that will be resolved to
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// each other, but aren't currently (thus we need to treat it as resolved).
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//
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static void GetAllUndefinedSymbols(Module *M,
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std::set<std::string> &UndefinedSymbols) {
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std::set<std::string> DefinedSymbols;
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UndefinedSymbols.clear(); // Start out empty
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for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
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if (I->hasName()) {
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if (I->isExternal())
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UndefinedSymbols.insert(I->getName());
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else if (!I->hasInternalLinkage())
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DefinedSymbols.insert(I->getName());
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}
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for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
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if (I->hasName()) {
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if (I->isExternal())
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UndefinedSymbols.insert(I->getName());
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else if (!I->hasInternalLinkage())
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DefinedSymbols.insert(I->getName());
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}
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// Prune out any defined symbols from the undefined symbols set...
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for (std::set<std::string>::iterator I = UndefinedSymbols.begin();
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I != UndefinedSymbols.end(); )
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if (DefinedSymbols.count(*I))
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UndefinedSymbols.erase(I++); // This symbol really is defined!
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else
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++I; // Keep this symbol in the undefined symbols list
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}
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static bool LinkLibrary(Module *M, const std::string &LibName,
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bool search, std::string &ErrorMessage) {
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std::set<std::string> UndefinedSymbols;
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GetAllUndefinedSymbols(M, UndefinedSymbols);
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if (UndefinedSymbols.empty()) {
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if (Verbose) std::cerr << " No symbols undefined, don't link library!\n";
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return false; // No need to link anything in!
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}
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std::vector<Module*> Objects;
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bool isArchive;
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if (LoadLibrary(LibName, Objects, isArchive, search, ErrorMessage))
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return true;
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// Figure out which symbols are defined by all of the modules in the .a file
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std::vector<std::set<std::string> > DefinedSymbols;
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DefinedSymbols.resize(Objects.size());
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for (unsigned i = 0; i != Objects.size(); ++i)
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GetAllDefinedSymbols(Objects[i], DefinedSymbols[i]);
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bool Linked = true;
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while (Linked) { // While we are linking in object files, loop.
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Linked = false;
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for (unsigned i = 0; i != Objects.size(); ++i) {
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// Consider whether we need to link in this module... we only need to
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// link it in if it defines some symbol which is so far undefined.
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//
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const std::set<std::string> &DefSymbols = DefinedSymbols[i];
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bool ObjectRequired = false;
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for (std::set<std::string>::iterator I = UndefinedSymbols.begin(),
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E = UndefinedSymbols.end(); I != E; ++I)
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if (DefSymbols.count(*I)) {
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if (Verbose)
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std::cerr << " Found object providing symbol '" << *I << "'...\n";
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ObjectRequired = true;
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break;
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}
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// We DO need to link this object into the program...
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if (ObjectRequired) {
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if (LinkModules(M, Objects[i], &ErrorMessage))
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return true; // Couldn't link in the right object file...
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// Since we have linked in this object, delete it from the list of
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// objects to consider in this archive file.
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std::swap(Objects[i], Objects.back());
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std::swap(DefinedSymbols[i], DefinedSymbols.back());
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Objects.pop_back();
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DefinedSymbols.pop_back();
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--i; // Do not skip an entry
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// The undefined symbols set should have shrunk.
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GetAllUndefinedSymbols(M, UndefinedSymbols);
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Linked = true; // We have linked something in!
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}
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}
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}
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return false;
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}
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static int PrintAndReturn(const char *progname, const std::string &Message,
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const std::string &Extra = "") {
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std::cerr << progname << Extra << ": " << Message << "\n";
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return 1;
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}
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int main(int argc, char **argv) {
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cl::ParseCommandLineOptions(argc, argv, " llvm linker for GCC\n");
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std::string ErrorMessage;
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std::auto_ptr<Module> Composite(LoadObject(InputFilenames[0], ErrorMessage));
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if (Composite.get() == 0)
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return PrintAndReturn(argv[0], ErrorMessage);
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// We always look first in the current directory when searching for libraries.
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LibPaths.insert(LibPaths.begin(), ".");
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// If the user specied an extra search path in their environment, respect it.
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if (char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH"))
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LibPaths.push_back(SearchPath);
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for (unsigned i = 1; i < InputFilenames.size(); ++i) {
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// A user may specify an ar archive without -l, perhaps because it
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// is not installed as a library. Detect that and link the library.
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if (IsArchive(InputFilenames[i])) {
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if (Verbose) std::cerr << "Linking archive '" << InputFilenames[i]
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<< "'\n";
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if (LinkLibrary(Composite.get(), InputFilenames[i], false, ErrorMessage))
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return PrintAndReturn(argv[0], ErrorMessage,
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": error linking in '" + InputFilenames[i] + "'");
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continue;
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}
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std::auto_ptr<Module> M(LoadObject(InputFilenames[i], ErrorMessage));
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if (M.get() == 0)
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return PrintAndReturn(argv[0], ErrorMessage);
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if (Verbose) std::cerr << "Linking in '" << InputFilenames[i] << "'\n";
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if (LinkModules(Composite.get(), M.get(), &ErrorMessage))
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return PrintAndReturn(argv[0], ErrorMessage,
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": error linking in '" + InputFilenames[i] + "'");
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}
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// Remove any consecutive duplicates of the same library...
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Libraries.erase(std::unique(Libraries.begin(), Libraries.end()),
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Libraries.end());
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// Link in all of the libraries next...
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for (unsigned i = 0; i != Libraries.size(); ++i) {
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if (Verbose) std::cerr << "Linking in library: -l" << Libraries[i] << "\n";
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if (LinkLibrary(Composite.get(), Libraries[i], true, ErrorMessage))
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return PrintAndReturn(argv[0], ErrorMessage);
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}
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// In addition to just linking the input from GCC, we also want to spiff it up
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// a little bit. Do this now.
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//
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PassManager Passes;
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// Add an appropriate TargetData instance for this module...
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Passes.add(new TargetData("gccld", Composite.get()));
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// Linking modules together can lead to duplicated global constants, only keep
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// one copy of each constant...
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//
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Passes.add(createConstantMergePass());
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// If the -s command line option was specified, strip the symbols out of the
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// resulting program to make it smaller. -s is a GCC option that we are
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// supporting.
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//
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if (Strip)
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Passes.add(createSymbolStrippingPass());
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// Often if the programmer does not specify proper prototypes for the
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// functions they are calling, they end up calling a vararg version of the
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// function that does not get a body filled in (the real function has typed
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// arguments). This pass merges the two functions.
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//
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Passes.add(createFunctionResolvingPass());
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if (!NoInternalize) {
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// Now that composite has been compiled, scan through the module, looking
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// for a main function. If main is defined, mark all other functions
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// internal.
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//
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Passes.add(createInternalizePass());
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}
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// Remove unused arguments from functions...
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//
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Passes.add(createDeadArgEliminationPass());
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// The FuncResolve pass may leave cruft around if functions were prototyped
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// differently than they were defined. Remove this cruft.
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//
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Passes.add(createInstructionCombiningPass());
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// Delete basic blocks, which optimization passes may have killed...
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//
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Passes.add(createCFGSimplificationPass());
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// Now that we have optimized the program, discard unreachable functions...
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//
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Passes.add(createGlobalDCEPass());
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// Add the pass that writes bytecode to the output file...
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std::string RealBytecodeOutput = OutputFilename;
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if (!LinkAsLibrary) RealBytecodeOutput += ".bc";
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std::ofstream Out(RealBytecodeOutput.c_str());
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if (!Out.good())
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return PrintAndReturn(argv[0], "error opening '" + RealBytecodeOutput +
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"' for writing!");
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Passes.add(new WriteBytecodePass(&Out)); // Write bytecode to file...
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// Make sure that the Out file gets unlink'd from the disk if we get a SIGINT
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RemoveFileOnSignal(RealBytecodeOutput);
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// Run our queue of passes all at once now, efficiently.
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Passes.run(*Composite.get());
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Out.close();
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if (!LinkAsLibrary) {
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// Output the script to start the program...
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std::ofstream Out2(OutputFilename.c_str());
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if (!Out2.good())
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return PrintAndReturn(argv[0], "error opening '" + OutputFilename +
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"' for writing!");
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Out2 << "#!/bin/sh\nlli -q -abort-on-exception $0.bc $*\n";
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Out2.close();
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// Make the script executable...
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chmod(OutputFilename.c_str(), 0755);
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// Make the bytecode file directly executable in LLEE as well
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chmod(RealBytecodeOutput.c_str(), 0755);
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}
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return 0;
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}
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