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+//===- llvm-ld.cpp - LLVM 'ld' compatible linker --------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This utility is intended to be compatible with GCC, and follows standard
+// system 'ld' conventions. As such, the default output file is ./a.out.
+// Additionally, this program outputs a shell script that is used to invoke LLI
+// to execute the program. In this manner, the generated executable (a.out for
+// example), is directly executable, whereas the bytecode file actually lives in
+// the a.out.bc file generated by this program. Also, Force is on by default.
+//
+// Note that if someone (or a script) deletes the executable program generated,
+// the .bc file will be left around. Considering that this is a temporary hack,
+// I'm not too worried about this.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Linker.h"
+#include "llvm/System/Program.h"
+#include "llvm/Module.h"
+#include "llvm/PassManager.h"
+#include "llvm/Bytecode/Reader.h"
+#include "llvm/Bytecode/Writer.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetMachineRegistry.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/FileUtilities.h"
+#include "llvm/Support/SystemUtils.h"
+#include "llvm/System/Signals.h"
+#include <fstream>
+#include <iostream>
+#include <memory>
+
+using namespace llvm;
+
+// Input/Output Options
+static cl::list<std::string> InputFilenames(cl::Positional, cl::OneOrMore,
+ cl::desc("<input bytecode files>"));
+
+static cl::opt<std::string> OutputFilename("o", cl::init("a.out"),
+ cl::desc("Override output filename"),
+ cl::value_desc("filename"));
+
+static cl::opt<bool> Verbose("v",
+ cl::desc("Print information about actions taken"));
+
+static cl::list<std::string> LibPaths("L", cl::Prefix,
+ cl::desc("Specify a library search path"),
+ cl::value_desc("directory"));
+
+static cl::list<std::string> Libraries("l", cl::Prefix,
+ cl::desc("Specify libraries to link to"),
+ cl::value_desc("library prefix"));
+
+static cl::opt<bool> LinkAsLibrary("link-as-library",
+ cl::desc("Link the .bc files together as a library, not an executable"));
+
+static cl::alias Relink("r", cl::aliasopt(LinkAsLibrary),
+ cl::desc("Alias for -link-as-library"));
+
+static cl::opt<const TargetMachineRegistry::Entry*, false, TargetNameParser>
+ MachineArch("march", cl::desc("Architecture to generate assembly for:"));
+
+static cl::opt<bool> Native("native",
+ cl::desc("Generate a native binary instead of a shell script"));
+
+static cl::opt<bool>NativeCBE("native-cbe",
+ cl::desc("Generate a native binary with the C backend and GCC"));
+
+static cl::opt<bool>DisableCompression("disable-compression",cl::init(false),
+ cl::desc("Disable writing of compressed bytecode files"));
+
+// Compatibility options that are ignored but supported by LD
+static cl::opt<std::string> CO3("soname", cl::Hidden,
+ cl::desc("Compatibility option: ignored"));
+
+static cl::opt<std::string> CO4("version-script", cl::Hidden,
+ cl::desc("Compatibility option: ignored"));
+
+static cl::opt<bool> CO5("eh-frame-hdr", cl::Hidden,
+ cl::desc("Compatibility option: ignored"));
+
+static cl::opt<std::string> CO6("h", cl::Hidden,
+ cl::desc("Compatibility option: ignored"));
+
+/// This is just for convenience so it doesn't have to be passed around
+/// everywhere.
+static std::string progname;
+
+/// PrintAndReturn - Prints a message to standard error and returns true.
+///
+/// Inputs:
+/// progname - The name of the program (i.e. argv[0]).
+/// Message - The message to print to standard error.
+///
+static int PrintAndReturn(const std::string &Message) {
+ std::cerr << progname << ": " << Message << "\n";
+ return 1;
+}
+
+/// CopyEnv - This function takes an array of environment variables and makes a
+/// copy of it. This copy can then be manipulated any way the caller likes
+/// without affecting the process's real environment.
+///
+/// Inputs:
+/// envp - An array of C strings containing an environment.
+///
+/// Return value:
+/// NULL - An error occurred.
+///
+/// Otherwise, a pointer to a new array of C strings is returned. Every string
+/// in the array is a duplicate of the one in the original array (i.e. we do
+/// not copy the char *'s from one array to another).
+///
+static char ** CopyEnv(char ** const envp) {
+ // Count the number of entries in the old list;
+ unsigned entries; // The number of entries in the old environment list
+ for (entries = 0; envp[entries] != NULL; entries++)
+ /*empty*/;
+
+ // Add one more entry for the NULL pointer that ends the list.
+ ++entries;
+
+ // If there are no entries at all, just return NULL.
+ if (entries == 0)
+ return NULL;
+
+ // Allocate a new environment list.
+ char **newenv = new char* [entries];
+ if ((newenv = new char* [entries]) == NULL)
+ return NULL;
+
+ // Make a copy of the list. Don't forget the NULL that ends the list.
+ entries = 0;
+ while (envp[entries] != NULL) {
+ newenv[entries] = new char[strlen (envp[entries]) + 1];
+ strcpy (newenv[entries], envp[entries]);
+ ++entries;
+ }
+ newenv[entries] = NULL;
+
+ return newenv;
+}
+
+
+/// RemoveEnv - Remove the specified environment variable from the environment
+/// array.
+///
+/// Inputs:
+/// name - The name of the variable to remove. It cannot be NULL.
+/// envp - The array of environment variables. It cannot be NULL.
+///
+/// Notes:
+/// This is mainly done because functions to remove items from the environment
+/// are not available across all platforms. In particular, Solaris does not
+/// seem to have an unsetenv() function or a setenv() function (or they are
+/// undocumented if they do exist).
+///
+static void RemoveEnv(const char * name, char ** const envp) {
+ for (unsigned index=0; envp[index] != NULL; index++) {
+ // Find the first equals sign in the array and make it an EOS character.
+ char *p = strchr (envp[index], '=');
+ if (p == NULL)
+ continue;
+ else
+ *p = '\0';
+
+ // Compare the two strings. If they are equal, zap this string.
+ // Otherwise, restore it.
+ if (!strcmp(name, envp[index]))
+ *envp[index] = '\0';
+ else
+ *p = '=';
+ }
+
+ return;
+}
+
+/// GenerateBytecode - generates a bytecode file from the module provided
+void GenerateBytecode(Module* M, const std::string& FileName) {
+
+ // Create the output file.
+ std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
+ std::ios::binary;
+ std::ofstream Out(FileName.c_str(), io_mode);
+ if (!Out.good()) {
+ PrintAndReturn("error opening '" + FileName + "' for writing!");
+ return;
+ }
+
+ // Ensure that the bytecode file gets removed from the disk if we get a
+ // terminating signal.
+ sys::RemoveFileOnSignal(sys::Path(FileName));
+
+ // Write it out
+ WriteBytecodeToFile(M, Out, !DisableCompression);
+
+ // Close the bytecode file.
+ Out.close();
+}
+
+/// GenerateAssembly - generates a native assembly language source file from the
+/// specified bytecode file.
+///
+/// Inputs:
+/// InputFilename - The name of the output bytecode file.
+/// OutputFilename - The name of the file to generate.
+/// llc - The pathname to use for LLC.
+/// envp - The environment to use when running LLC.
+///
+/// Return non-zero value on error.
+///
+static int GenerateAssembly(const std::string &OutputFilename,
+ const std::string &InputFilename,
+ const sys::Path &llc) {
+ // Run LLC to convert the bytecode file into assembly code.
+ std::vector<const char*> args;
+ args.push_back(llc.c_str());
+ args.push_back("-f");
+ args.push_back("-o");
+ args.push_back(OutputFilename.c_str());
+ args.push_back(InputFilename.c_str());
+ args.push_back(0);
+
+ return sys::Program::ExecuteAndWait(llc,&args[0]);
+}
+
+/// GenerateAssembly - generates a native assembly language source file from the
+/// specified bytecode file.
+static int GenerateCFile(const std::string &OutputFile,
+ const std::string &InputFile,
+ const sys::Path &llc) {
+ // Run LLC to convert the bytecode file into C.
+ std::vector<const char*> args;
+ args.push_back(llc.c_str());
+ args.push_back("-march=c");
+ args.push_back("-f");
+ args.push_back("-o");
+ args.push_back(OutputFile.c_str());
+ args.push_back(InputFile.c_str());
+ args.push_back(0);
+ return sys::Program::ExecuteAndWait(llc, &args[0]);
+}
+
+/// GenerateNative - generates a native assembly language source file from the
+/// specified assembly source file.
+///
+/// Inputs:
+/// InputFilename - The name of the output bytecode file.
+/// OutputFilename - The name of the file to generate.
+/// Libraries - The list of libraries with which to link.
+/// LibPaths - The list of directories in which to find libraries.
+/// gcc - The pathname to use for GGC.
+/// envp - A copy of the process's current environment.
+///
+/// Outputs:
+/// None.
+///
+/// Returns non-zero value on error.
+///
+static int GenerateNative(const std::string &OutputFilename,
+ const std::string &InputFilename,
+ const std::vector<std::string> &Libraries,
+ const sys::Path &gcc, char ** const envp) {
+ // Remove these environment variables from the environment of the
+ // programs that we will execute. It appears that GCC sets these
+ // environment variables so that the programs it uses can configure
+ // themselves identically.
+ //
+ // However, when we invoke GCC below, we want it to use its normal
+ // configuration. Hence, we must sanitize its environment.
+ char ** clean_env = CopyEnv(envp);
+ if (clean_env == NULL)
+ return 1;
+ RemoveEnv("LIBRARY_PATH", clean_env);
+ RemoveEnv("COLLECT_GCC_OPTIONS", clean_env);
+ RemoveEnv("GCC_EXEC_PREFIX", clean_env);
+ RemoveEnv("COMPILER_PATH", clean_env);
+ RemoveEnv("COLLECT_GCC", clean_env);
+
+
+ // Run GCC to assemble and link the program into native code.
+ //
+ // Note:
+ // We can't just assemble and link the file with the system assembler
+ // and linker because we don't know where to put the _start symbol.
+ // GCC mysteriously knows how to do it.
+ std::vector<const char*> args;
+ args.push_back(gcc.c_str());
+ args.push_back("-fno-strict-aliasing");
+ args.push_back("-O3");
+ args.push_back("-o");
+ args.push_back(OutputFilename.c_str());
+ args.push_back(InputFilename.c_str());
+
+ // Add in the libraries to link.
+ for (unsigned index = 0; index < Libraries.size(); index++)
+ if (Libraries[index] != "crtend") {
+ args.push_back("-l");
+ args.push_back(Libraries[index].c_str());
+ }
+ args.push_back(0);
+
+ // Run the compiler to assembly and link together the program.
+ return sys::Program::ExecuteAndWait(gcc, &args[0], (const char**)clean_env);
+}
+
+/// EmitShellScript - Output the wrapper file that invokes the JIT on the LLVM
+/// bytecode file for the program.
+static void EmitShellScript(char **argv) {
+#if defined(_WIN32) || defined(__CYGWIN__)
+ // Windows doesn't support #!/bin/sh style shell scripts in .exe files. To
+ // support windows systems, we copy the llvm-stub.exe executable from the
+ // build tree to the destination file.
+ sys::Path llvmstub = FindExecutable("llvm-stub.exe", argv[0]);
+ if (llvmstub.isEmpty()) {
+ std::cerr << "Could not find llvm-stub.exe executable!\n";
+ exit(1);
+ }
+ sys::CopyFile(sys::Path(OutputFilename), llvmstub);
+ return;
+#endif
+
+ // Output the script to start the program...
+ std::ofstream Out2(OutputFilename.c_str());
+ if (!Out2.good())
+ exit(PrintAndReturn("error opening '" + OutputFilename + "' for writing!"));
+
+ Out2 << "#!/bin/sh\n";
+ // Allow user to setenv LLVMINTERP if lli is not in their PATH.
+ Out2 << "lli=${LLVMINTERP-lli}\n";
+ Out2 << "exec $lli \\\n";
+ // gcc accepts -l<lib> and implicitly searches /lib and /usr/lib.
+ LibPaths.push_back("/lib");
+ LibPaths.push_back("/usr/lib");
+ LibPaths.push_back("/usr/X11R6/lib");
+ // We don't need to link in libc! In fact, /usr/lib/libc.so may not be a
+ // shared object at all! See RH 8: plain text.
+ std::vector<std::string>::iterator libc =
+ std::find(Libraries.begin(), Libraries.end(), "c");
+ if (libc != Libraries.end()) Libraries.erase(libc);
+ // List all the shared object (native) libraries this executable will need
+ // on the command line, so that we don't have to do this manually!
+ for (std::vector<std::string>::iterator i = Libraries.begin(),
+ e = Libraries.end(); i != e; ++i) {
+ sys::Path FullLibraryPath = sys::Path::FindLibrary(*i);
+ if (!FullLibraryPath.isEmpty() && FullLibraryPath.isDynamicLibrary())
+ Out2 << " -load=" << FullLibraryPath.toString() << " \\\n";
+ }
+ Out2 << " $0.bc ${1+\"$@\"}\n";
+ Out2.close();
+}
+
+// BuildLinkItems -- This function generates a LinkItemList for the LinkItems
+// linker function by combining the Files and Libraries in the order they were
+// declared on the command line.
+static void BuildLinkItems(
+ Linker::ItemList& Items,
+ const cl::list<std::string>& Files,
+ const cl::list<std::string>& Libraries) {
+
+ // Build the list of linkage items for LinkItems.
+
+ cl::list<std::string>::const_iterator fileIt = Files.begin();
+ cl::list<std::string>::const_iterator libIt = Libraries.begin();
+
+ int libPos = -1, filePos = -1;
+ while ( libIt != Libraries.end() || fileIt != Files.end() ) {
+ if (libIt != Libraries.end())
+ libPos = Libraries.getPosition(libIt - Libraries.begin());
+ else
+ libPos = -1;
+ if (fileIt != Files.end())
+ filePos = Files.getPosition(fileIt - Files.begin());
+ else
+ filePos = -1;
+
+ if (filePos != -1 && (libPos == -1 || filePos < libPos)) {
+ // Add a source file
+ Items.push_back(std::make_pair(*fileIt++, false));
+ } else if (libPos != -1 && (filePos == -1 || libPos < filePos)) {
+ // Add a library
+ Items.push_back(std::make_pair(*libIt++, true));
+ }
+ }
+}
+
+// Rightly this should go in a header file but it just seems such a waste.
+namespace llvm {
+extern void Optimize(Module*);
+}
+
+int main(int argc, char **argv, char **envp) {
+ try {
+ // Initial global variable above for convenience printing of program name.
+ progname = sys::Path(argv[0]).getBasename();
+ Linker TheLinker(progname, Verbose);
+
+ // Set up the library paths for the Linker
+ TheLinker.addPaths(LibPaths);
+ TheLinker.addSystemPaths();
+
+ // Parse the command line options
+ cl::ParseCommandLineOptions(argc, argv, " llvm linker\n");
+ sys::PrintStackTraceOnErrorSignal();
+
+ // Remove any consecutive duplicates of the same library...
+ Libraries.erase(std::unique(Libraries.begin(), Libraries.end()),
+ Libraries.end());
+
+ if (LinkAsLibrary) {
+ std::vector<sys::Path> Files;
+ for (unsigned i = 0; i < InputFilenames.size(); ++i )
+ Files.push_back(sys::Path(InputFilenames[i]));
+ if (TheLinker.LinkInFiles(Files))
+ return 1; // Error already printed
+
+ // The libraries aren't linked in but are noted as "dependent" in the
+ // module.
+ for (cl::list<std::string>::const_iterator I = Libraries.begin(),
+ E = Libraries.end(); I != E ; ++I) {
+ TheLinker.getModule()->addLibrary(*I);
+ }
+ } else {
+ // Build a list of the items from our command line
+ Linker::ItemList Items;
+ BuildLinkItems(Items, InputFilenames, Libraries);
+
+ // Link all the items together
+ if (TheLinker.LinkInItems(Items) )
+ return 1;
+ }
+
+ std::auto_ptr<Module> Composite(TheLinker.releaseModule());
+
+ // Optimize the module
+ Optimize(Composite.get());
+
+ // Generate the bytecode for the optimized module.
+ std::string RealBytecodeOutput = OutputFilename;
+ if (!LinkAsLibrary) RealBytecodeOutput += ".bc";
+ GenerateBytecode(Composite.get(), RealBytecodeOutput);
+
+ // If we are not linking a library, generate either a native executable
+ // or a JIT shell script, depending upon what the user wants.
+ if (!LinkAsLibrary) {
+ // If the user wants to generate a native executable, compile it from the
+ // bytecode file.
+ //
+ // Otherwise, create a script that will run the bytecode through the JIT.
+ if (Native) {
+ // Name of the Assembly Language output file
+ sys::Path AssemblyFile ( OutputFilename);
+ AssemblyFile.appendSuffix("s");
+
+ // Mark the output files for removal if we get an interrupt.
+ sys::RemoveFileOnSignal(AssemblyFile);
+ sys::RemoveFileOnSignal(sys::Path(OutputFilename));
+
+ // Determine the locations of the llc and gcc programs.
+ sys::Path llc = FindExecutable("llc", argv[0]);
+ if (llc.isEmpty())
+ return PrintAndReturn("Failed to find llc");
+
+ sys::Path gcc = FindExecutable("gcc", argv[0]);
+ if (gcc.isEmpty())
+ return PrintAndReturn("Failed to find gcc");
+
+ // Generate an assembly language file for the bytecode.
+ if (Verbose) std::cout << "Generating Assembly Code\n";
+ GenerateAssembly(AssemblyFile.toString(), RealBytecodeOutput, llc);
+ if (Verbose) std::cout << "Generating Native Code\n";
+ GenerateNative(OutputFilename, AssemblyFile.toString(), Libraries,
+ gcc, envp);
+
+ // Remove the assembly language file.
+ AssemblyFile.eraseFromDisk();
+ } else if (NativeCBE) {
+ sys::Path CFile (OutputFilename);
+ CFile.appendSuffix("cbe.c");
+
+ // Mark the output files for removal if we get an interrupt.
+ sys::RemoveFileOnSignal(CFile);
+ sys::RemoveFileOnSignal(sys::Path(OutputFilename));
+
+ // Determine the locations of the llc and gcc programs.
+ sys::Path llc = FindExecutable("llc", argv[0]);
+ if (llc.isEmpty())
+ return PrintAndReturn("Failed to find llc");
+
+ sys::Path gcc = FindExecutable("gcc", argv[0]);
+ if (gcc.isEmpty())
+ return PrintAndReturn("Failed to find gcc");
+
+ // Generate an assembly language file for the bytecode.
+ if (Verbose) std::cout << "Generating Assembly Code\n";
+ GenerateCFile(CFile.toString(), RealBytecodeOutput, llc);
+ if (Verbose) std::cout << "Generating Native Code\n";
+ GenerateNative(OutputFilename, CFile.toString(), Libraries, gcc, envp);
+
+ // Remove the assembly language file.
+ CFile.eraseFromDisk();
+
+ } else {
+ EmitShellScript(argv);
+ }
+
+ // Make the script executable...
+ sys::Path(OutputFilename).makeExecutableOnDisk();
+
+ // Make the bytecode file readable and directly executable in LLEE as well
+ sys::Path(RealBytecodeOutput).makeExecutableOnDisk();
+ sys::Path(RealBytecodeOutput).makeReadableOnDisk();
+ }
+
+ return 0;
+ } catch (const std::string& msg) {
+ std::cerr << argv[0] << ": " << msg << "\n";
+ } catch (...) {
+ std::cerr << argv[0] << ": Unexpected unknown exception occurred.\n";
+ }
+ return 1;
+}
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