Initial implementation of llvm-ld: stolen from gccld.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16305 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 303 insertions, 0 deletions

diff --git a/tools/llvm-ld/llvm-ld.cpp b/tools/llvm-ld/llvm-ld.cpp
new file mode 100644
index 0000000000..d59b18acb5
--- /dev/null
+++ b/tools/llvm-ld/llvm-ld.cpp
@@ -0,0 +1,303 @@
+//===- 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-ld.h"
+#include "llvm/Module.h"
+#include "llvm/PassManager.h"
+#include "llvm/Bytecode/Reader.h"
+#include "llvm/Bytecode/WriteBytecodePass.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Support/Linker.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/FileUtilities.h"
+#include "llvm/System/Signals.h"
+#include "llvm/Support/SystemUtils.h"
+#include <fstream>
+#include <memory>
+using namespace llvm;
+
+enum OptimizationLevels {
+  OPT_FAST_COMPILE,
+  OPT_SIMPLE,
+  OPT_AGGRESSIVE,
+  OPT_LINK_TIME,
+  OPT_AGGRESSIVE_LINK_TIME
+};
+
+namespace {
+  cl::list<std::string> 
+  InputFilenames(cl::Positional, cl::desc("<input bytecode files>"),
+                 cl::OneOrMore);
+
+  cl::opt<std::string> 
+  OutputFilename("o", cl::desc("Override output filename"), cl::init("a.out"),
+                 cl::value_desc("filename"));
+
+  cl::opt<bool>    
+  Verbose("v", cl::desc("Print information about actions taken"));
+  
+  cl::list<std::string> 
+  LibPaths("L", cl::desc("Specify a library search path"), cl::Prefix,
+           cl::value_desc("directory"));
+
+  cl::list<std::string> 
+  Libraries("l", cl::desc("Specify libraries to link to"), cl::Prefix,
+            cl::value_desc("library prefix"));
+
+  cl::opt<bool>
+  Strip("s", cl::desc("Strip symbol info from executable"));
+
+  cl::opt<bool>
+  NoInternalize("disable-internalize",
+                cl::desc("Do not mark all symbols as internal"));
+  cl::alias
+  ExportDynamic("export-dynamic", cl::desc("Alias for -disable-internalize"),
+                cl::aliasopt(NoInternalize));
+
+  cl::opt<bool>
+  LinkAsLibrary("link-as-library", cl::desc("Link the .bc files together as a"
+                                            " library, not an executable"));
+  cl::alias
+  Relink("r", cl::desc("Alias for -link-as-library"),
+         cl::aliasopt(LinkAsLibrary));
+
+  cl::opt<bool>    
+  Native("native",
+         cl::desc("Generate a native binary instead of a shell script"));
+  cl::opt<bool>    
+  NativeCBE("native-cbe",
+            cl::desc("Generate a native binary with the C backend and GCC"));
+  
+  // Compatibility options that are ignored but supported by LD
+  cl::opt<std::string>
+  CO3("soname", cl::Hidden, cl::desc("Compatibility option: ignored"));
+  cl::opt<std::string>
+  CO4("version-script", cl::Hidden, cl::desc("Compatibility option: ignored"));
+  cl::opt<bool>
+  CO5("eh-frame-hdr", cl::Hidden, cl::desc("Compatibility option: ignored"));
+  cl::opt<std::string>
+  CO6("h", cl::Hidden, cl::desc("Compatibility option: ignored"));
+
+  cl::opt<OptimizationLevels> OptLevel(
+    cl::desc("Choose level of optimization to apply:"),
+    cl::init(OPT_FAST_COMPILE), cl::values(
+      clEnumValN(OPT_FAST_COMPILE,"O0",
+        "An alias for the -O1 option."),
+      clEnumValN(OPT_FAST_COMPILE,"O1",
+        "Optimize for linking speed, not execution speed."),
+      clEnumValN(OPT_SIMPLE,"O2",
+        "Perform only required/minimal optimizations"),
+      clEnumValN(OPT_AGGRESSIVE,"O3",
+        "An alias for the -O2 option."),
+      clEnumValN(OPT_LINK_TIME,"O4",
+        "Perform standard link time optimizations"),
+      clEnumValN(OPT_AGGRESSIVE_LINK_TIME,"O5",
+        "Perform aggressive link time optimizations"),
+      clEnumValEnd
+    )
+  );
+}
+
+/// 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 char *progname, const std::string &Message) {
+  std::cerr << progname << ": " << Message << "\n";
+  return 1;
+}
+
+/// 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.
+  std::string llvmstub = FindExecutable("llvm-stub.exe", argv[0]);
+  if (llvmstub.empty()) {
+    std::cerr << "Could not find llvm-stub.exe executable!\n";
+    exit(1);
+  }
+  if (CopyFile(OutputFilename, llvmstub)) {
+    std::cerr << "Could not copy the llvm-stub.exe executable!\n";
+    exit(1);
+  }
+  return;
+#endif
+
+  // Output the script to start the program...
+  std::ofstream Out2(OutputFilename.c_str());
+  if (!Out2.good())
+    exit(PrintAndReturn(argv[0], "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) {
+    std::string FullLibraryPath = FindLib(*i, LibPaths, true);
+    if (!FullLibraryPath.empty() && IsSharedObject(FullLibraryPath))
+      Out2 << "    -load=" << FullLibraryPath << " \\\n";
+  }
+  Out2 << "    $0.bc ${1+\"$@\"}\n";
+  Out2.close();
+}
+
+int main(int argc, char **argv, char **envp) {
+  cl::ParseCommandLineOptions(argc, argv, " llvm linker for GCC\n");
+  sys::PrintStackTraceOnErrorSignal();
+
+  std::string ModuleID("gccld-output");
+  std::auto_ptr<Module> Composite(new Module(ModuleID));
+
+  // We always look first in the current directory when searching for libraries.
+  LibPaths.insert(LibPaths.begin(), ".");
+
+  // If the user specified an extra search path in their environment, respect
+  // it.
+  if (char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH"))
+    LibPaths.push_back(SearchPath);
+
+  // Remove any consecutive duplicates of the same library...
+  Libraries.erase(std::unique(Libraries.begin(), Libraries.end()),
+                  Libraries.end());
+
+  // Link in all of the files
+  if (LinkFiles(argv[0], Composite.get(), InputFilenames, Verbose))
+    return 1; // Error already printed
+
+  if (!LinkAsLibrary)
+    LinkLibraries(argv[0], Composite.get(), Libraries, LibPaths,
+                  Verbose, Native);
+
+  // Link in all of the libraries next...
+
+  // Create the output file.
+  std::string RealBytecodeOutput = OutputFilename;
+  if (!LinkAsLibrary) RealBytecodeOutput += ".bc";
+  std::ofstream Out(RealBytecodeOutput.c_str());
+  if (!Out.good())
+    return PrintAndReturn(argv[0], "error opening '" + RealBytecodeOutput +
+                                   "' for writing!");
+
+  // Ensure that the bytecode file gets removed from the disk if we get a
+  // SIGINT signal.
+  sys::RemoveFileOnSignal(RealBytecodeOutput);
+
+  // Generate the bytecode file.
+  if (GenerateBytecode(Composite.get(), Strip, !NoInternalize, &Out)) {
+    Out.close();
+    return PrintAndReturn(argv[0], "error generating bytecode");
+  }
+
+  // Close the bytecode file.
+  Out.close();
+
+  // 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
+      std::string AssemblyFile = OutputFilename + ".s";
+
+      // Mark the output files for removal if we get an interrupt.
+      sys::RemoveFileOnSignal(AssemblyFile);
+      sys::RemoveFileOnSignal(OutputFilename);
+
+      // Determine the locations of the llc and gcc programs.
+      std::string llc = FindExecutable("llc", argv[0]);
+      std::string gcc = FindExecutable("gcc", argv[0]);
+      if (llc.empty())
+        return PrintAndReturn(argv[0], "Failed to find llc");
+
+      if (gcc.empty())
+        return PrintAndReturn(argv[0], "Failed to find gcc");
+
+      // Generate an assembly language file for the bytecode.
+      if (Verbose) std::cout << "Generating Assembly Code\n";
+      GenerateAssembly(AssemblyFile, RealBytecodeOutput, llc, envp);
+      if (Verbose) std::cout << "Generating Native Code\n";
+      GenerateNative(OutputFilename, AssemblyFile, Libraries, LibPaths,
+                     gcc, envp);
+
+      // Remove the assembly language file.
+      removeFile (AssemblyFile);
+    } else if (NativeCBE) {
+      std::string CFile = OutputFilename + ".cbe.c";
+
+      // Mark the output files for removal if we get an interrupt.
+      sys::RemoveFileOnSignal(CFile);
+      sys::RemoveFileOnSignal(OutputFilename);
+
+      // Determine the locations of the llc and gcc programs.
+      std::string llc = FindExecutable("llc", argv[0]);
+      std::string gcc = FindExecutable("gcc", argv[0]);
+      if (llc.empty())
+        return PrintAndReturn(argv[0], "Failed to find llc");
+      if (gcc.empty())
+        return PrintAndReturn(argv[0], "Failed to find gcc");
+
+      // Generate an assembly language file for the bytecode.
+      if (Verbose) std::cout << "Generating Assembly Code\n";
+      GenerateCFile(CFile, RealBytecodeOutput, llc, envp);
+      if (Verbose) std::cout << "Generating Native Code\n";
+      GenerateNative(OutputFilename, CFile, Libraries, LibPaths, gcc, envp);
+
+      // Remove the assembly language file.
+      removeFile(CFile);
+
+    } else {
+      EmitShellScript(argv);
+    }
+  
+    // Make the script executable...
+    MakeFileExecutable(OutputFilename);
+
+    // Make the bytecode file readable and directly executable in LLEE as well
+    MakeFileExecutable(RealBytecodeOutput);
+    MakeFileReadable(RealBytecodeOutput);
+  }
+
+  return 0;
+}