tools/lli/lli.cpp

   1 //===- lli.cpp - LLVM Interpreter / Dynamic compiler ----------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This utility provides a simple wrapper around the LLVM Execution Engines,
  11 // which allow the direct execution of LLVM programs through a Just-In-Time
  12 // compiler, or through an intepreter if no JIT is available for this platform.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #include "llvm/Module.h"
  17 #include "llvm/ModuleProvider.h"
  18 #include "llvm/Type.h"
  19 #include "llvm/Bitcode/ReaderWriter.h"
  20 #include "llvm/CodeGen/LinkAllCodegenComponents.h"
  21 #include "llvm/ExecutionEngine/JIT.h"
  22 #include "llvm/ExecutionEngine/Interpreter.h"
  23 #include "llvm/ExecutionEngine/GenericValue.h"
  24 #include "llvm/Support/CommandLine.h"
  25 #include "llvm/Support/ManagedStatic.h"
  26 #include "llvm/Support/MemoryBuffer.h"
  27 #include "llvm/Support/PluginLoader.h"
  28 #include "llvm/Support/PrettyStackTrace.h"
  29 #include "llvm/System/Process.h"
  30 #include "llvm/System/Signals.h"
  31 #include <iostream>
  32 #include <cerrno>
  33 using namespace llvm;
  34
  35 namespace {
  36   cl::opt<std::string>
  37   InputFile(cl::desc("<input bitcode>"), cl::Positional, cl::init("-"));
  38
  39   cl::list<std::string>
  40   InputArgv(cl::ConsumeAfter, cl::desc("<program arguments>..."));
  41
  42   cl::opt<bool> ForceInterpreter("force-interpreter",
  43                                  cl::desc("Force interpretation: disable JIT"),
  44                                  cl::init(false));
  45
  46   // Determine optimization level.
  47   cl::opt<char>
  48   OptLevel("O",
  49            cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
  50                     "(default = '-O2')"),
  51            cl::Prefix,
  52            cl::ZeroOrMore,
  53            cl::init(' '));
  54
  55   cl::opt<std::string>
  56   TargetTriple("mtriple", cl::desc("Override target triple for module"));
  57
  58   cl::opt<std::string>
  59   EntryFunc("entry-function",
  60             cl::desc("Specify the entry function (default = 'main') "
  61                      "of the executable"),
  62             cl::value_desc("function"),
  63             cl::init("main"));
  64
  65   cl::opt<std::string>
  66   FakeArgv0("fake-argv0",
  67             cl::desc("Override the 'argv[0]' value passed into the executing"
  68                      " program"), cl::value_desc("executable"));
  69
  70   cl::opt<bool>
  71   DisableCoreFiles("disable-core-files", cl::Hidden,
  72                    cl::desc("Disable emission of core files if possible"));
  73
  74   cl::opt<bool>
  75   NoLazyCompilation("disable-lazy-compilation",
  76                   cl::desc("Disable JIT lazy compilation"),
  77                   cl::init(false));
  78 }
  79
  80 static ExecutionEngine *EE = 0;
  81
  82 static void do_shutdown() {
  83   delete EE;
  84   llvm_shutdown();
  85 }
  86
  87 //===----------------------------------------------------------------------===//
  88 // main Driver function
  89 //
  90 int main(int argc, char **argv, char * const *envp) {
  91   sys::PrintStackTraceOnErrorSignal();
  92   PrettyStackTraceProgram X(argc, argv);
  93
  94   atexit(do_shutdown);  // Call llvm_shutdown() on exit.
  95   cl::ParseCommandLineOptions(argc, argv,
  96                               "llvm interpreter & dynamic compiler\n");
  97
  98   // If the user doesn't want core files, disable them.
  99   if (DisableCoreFiles)
 100     sys::Process::PreventCoreFiles();
 101
 102   // Load the bitcode...
 103   std::string ErrorMsg;
 104   ModuleProvider *MP = NULL;
 105   if (MemoryBuffer *Buffer = MemoryBuffer::getFileOrSTDIN(InputFile,&ErrorMsg)) {
 106     MP = getBitcodeModuleProvider(Buffer, &ErrorMsg);
 107     if (!MP) delete Buffer;
 108   }
 109
 110   if (!MP) {
 111     std::cerr << argv[0] << ": error loading program '" << InputFile << "': "
 112               << ErrorMsg << "\n";
 113     exit(1);
 114   }
 115
 116   // Get the module as the MP could go away once EE takes over.
 117   Module *Mod = NoLazyCompilation
 118     ? MP->materializeModule(&ErrorMsg) : MP->getModule();
 119   if (!Mod) {
 120     std::cerr << argv[0] << ": bitcode didn't read correctly.\n";
 121     std::cerr << "Reason: " << ErrorMsg << "\n";
 122     exit(1);
 123   }
 124
 125   // If we are supposed to override the target triple, do so now.
 126   if (!TargetTriple.empty())
 127     Mod->setTargetTriple(TargetTriple);
 128
 129   CodeGenOpt::Level OLvl = CodeGenOpt::Default;
 130   switch (OptLevel) {
 131   default:
 132     std::cerr << argv[0] << ": invalid optimization level.\n";
 133     return 1;
 134   case ' ': break;
 135   case '0': OLvl = CodeGenOpt::None; break;
 136   case '1':
 137   case '2': OLvl = CodeGenOpt::Default; break;
 138   case '3': OLvl = CodeGenOpt::Aggressive; break;
 139   }
 140
 141   EE = ExecutionEngine::create(MP, ForceInterpreter, &ErrorMsg, OLvl);
 142   if (!EE && !ErrorMsg.empty()) {
 143     std::cerr << argv[0] << ":error creating EE: " << ErrorMsg << "\n";
 144     exit(1);
 145   }
 146
 147   if (NoLazyCompilation)
 148     EE->DisableLazyCompilation();
 149
 150   // If the user specifically requested an argv[0] to pass into the program,
 151   // do it now.
 152   if (!FakeArgv0.empty()) {
 153     InputFile = FakeArgv0;
 154   } else {
 155     // Otherwise, if there is a .bc suffix on the executable strip it off, it
 156     // might confuse the program.
 157     if (InputFile.rfind(".bc") == InputFile.length() - 3)
 158       InputFile.erase(InputFile.length() - 3);
 159   }
 160
 161   // Add the module's name to the start of the vector of arguments to main().
 162   InputArgv.insert(InputArgv.begin(), InputFile);
 163
 164   // Call the main function from M as if its signature were:
 165   //   int main (int argc, char **argv, const char **envp)
 166   // using the contents of Args to determine argc & argv, and the contents of
 167   // EnvVars to determine envp.
 168   //
 169   Function *EntryFn = Mod->getFunction(EntryFunc);
 170   if (!EntryFn) {
 171     std::cerr << '\'' << EntryFunc << "\' function not found in module.\n";
 172     return -1;
 173   }
 174
 175   // If the program doesn't explicitly call exit, we will need the Exit
 176   // function later on to make an explicit call, so get the function now.
 177   Constant *Exit = Mod->getOrInsertFunction("exit", Type::VoidTy,
 178                                                         Type::Int32Ty, NULL);
 179
 180   // Reset errno to zero on entry to main.
 181   errno = 0;
 182
 183   // Run static constructors.
 184   EE->runStaticConstructorsDestructors(false);
 185
 186   if (NoLazyCompilation) {
 187     for (Module::iterator I = Mod->begin(), E = Mod->end(); I != E; ++I) {
 188       Function *Fn = &*I;
 189       if (Fn != EntryFn && !Fn->isDeclaration())
 190         EE->getPointerToFunction(Fn);
 191     }
 192   }
 193
 194   // Run main.
 195   int Result = EE->runFunctionAsMain(EntryFn, InputArgv, envp);
 196
 197   // Run static destructors.
 198   EE->runStaticConstructorsDestructors(true);
 199
 200   // If the program didn't call exit explicitly, we should call it now.
 201   // This ensures that any atexit handlers get called correctly.
 202   if (Function *ExitF = dyn_cast<Function>(Exit)) {
 203     std::vector<GenericValue> Args;
 204     GenericValue ResultGV;
 205     ResultGV.IntVal = APInt(32, Result);
 206     Args.push_back(ResultGV);
 207     EE->runFunction(ExitF, Args);
 208     std::cerr << "ERROR: exit(" << Result << ") returned!\n";
 209     abort();
 210   } else {
 211     std::cerr << "ERROR: exit defined with wrong prototype!\n";
 212     abort();
 213   }
 214 }