tools/lli/lli.cpp

   1 //===- lli.cpp - LLVM Interpreter / Dynamic compiler ----------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file was developed by the LLVM research group and is distributed under
   6 // the University of Illinois Open Source 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/System/Process.h"
  29 #include "llvm/System/Signals.h"
  30 #include <iostream>
  31 #include <cerrno>
  32 using namespace llvm;
  33
  34 namespace {
  35   cl::opt<std::string>
  36   InputFile(cl::desc("<input bitcode>"), cl::Positional, cl::init("-"));
  37
  38   cl::list<std::string>
  39   InputArgv(cl::ConsumeAfter, cl::desc("<program arguments>..."));
  40
  41   cl::opt<bool> ForceInterpreter("force-interpreter",
  42                                  cl::desc("Force interpretation: disable JIT"),
  43                                  cl::init(false));
  44   cl::opt<std::string>
  45   TargetTriple("mtriple", cl::desc("Override target triple for module"));
  46
  47   cl::opt<std::string>
  48   FakeArgv0("fake-argv0",
  49             cl::desc("Override the 'argv[0]' value passed into the executing"
  50                      " program"), cl::value_desc("executable"));
  51
  52   cl::opt<bool>
  53   DisableCoreFiles("disable-core-files", cl::Hidden,
  54                    cl::desc("Disable emission of core files if possible"));
  55 }
  56
  57 static ExecutionEngine *EE = 0;
  58
  59 static void do_shutdown() {
  60   delete EE;
  61   llvm_shutdown();
  62 }
  63
  64 //===----------------------------------------------------------------------===//
  65 // main Driver function
  66 //
  67 int main(int argc, char **argv, char * const *envp) {
  68   atexit(do_shutdown);  // Call llvm_shutdown() on exit.
  69   cl::ParseCommandLineOptions(argc, argv,
  70                               " llvm interpreter & dynamic compiler\n");
  71   sys::PrintStackTraceOnErrorSignal();
  72
  73   // If the user doesn't want core files, disable them.
  74   if (DisableCoreFiles)
  75     sys::Process::PreventCoreFiles();
  76
  77   // Load the bitcode...
  78   std::string ErrorMsg;
  79   ModuleProvider *MP = 0;
  80   if (MemoryBuffer *Buffer = MemoryBuffer::getFileOrSTDIN(InputFile,&ErrorMsg)){
  81     MP = getBitcodeModuleProvider(Buffer, &ErrorMsg);
  82     if (!MP) delete Buffer;
  83   }
  84
  85   if (!MP) {
  86     std::cerr << argv[0] << ": error loading program '" << InputFile << "': "
  87               << ErrorMsg << "\n";
  88     exit(1);
  89   }
  90
  91   // Get the module as the MP could go away once EE takes over.
  92   Module *Mod = MP->getModule();
  93
  94   // If we are supposed to override the target triple, do so now.
  95   if (!TargetTriple.empty())
  96     Mod->setTargetTriple(TargetTriple);
  97
  98   EE = ExecutionEngine::create(MP, ForceInterpreter, &ErrorMsg);
  99   if (!EE && !ErrorMsg.empty()) {
 100     std::cerr << argv[0] << ":error creating EE: " << ErrorMsg << "\n";
 101     exit(1);
 102   }
 103
 104   // If the user specifically requested an argv[0] to pass into the program,
 105   // do it now.
 106   if (!FakeArgv0.empty()) {
 107     InputFile = FakeArgv0;
 108   } else {
 109     // Otherwise, if there is a .bc suffix on the executable strip it off, it
 110     // might confuse the program.
 111     if (InputFile.rfind(".bc") == InputFile.length() - 3)
 112       InputFile.erase(InputFile.length() - 3);
 113   }
 114
 115   // Add the module's name to the start of the vector of arguments to main().
 116   InputArgv.insert(InputArgv.begin(), InputFile);
 117
 118   // Call the main function from M as if its signature were:
 119   //   int main (int argc, char **argv, const char **envp)
 120   // using the contents of Args to determine argc & argv, and the contents of
 121   // EnvVars to determine envp.
 122   //
 123   Function *Fn = Mod->getFunction("main");
 124   if (!Fn) {
 125     std::cerr << "'main' function not found in module.\n";
 126     return -1;
 127   }
 128
 129   // If the program doesn't explicitly call exit, we will need the Exit
 130   // function later on to make an explicit call, so get the function now.
 131   Constant *Exit = Mod->getOrInsertFunction("exit", Type::VoidTy,
 132                                                         Type::Int32Ty, NULL);
 133
 134   // Reset errno to zero on entry to main.
 135   errno = 0;
 136
 137   // Run static constructors.
 138   EE->runStaticConstructorsDestructors(false);
 139
 140   // Run main.
 141   int Result = EE->runFunctionAsMain(Fn, InputArgv, envp);
 142
 143   // Run static destructors.
 144   EE->runStaticConstructorsDestructors(true);
 145
 146   // If the program didn't call exit explicitly, we should call it now.
 147   // This ensures that any atexit handlers get called correctly.
 148   if (Function *ExitF = dyn_cast<Function>(Exit)) {
 149     std::vector<GenericValue> Args;
 150     GenericValue ResultGV;
 151     ResultGV.IntVal = APInt(32, Result);
 152     Args.push_back(ResultGV);
 153     EE->runFunction(ExitF, Args);
 154     std::cerr << "ERROR: exit(" << Result << ") returned!\n";
 155     abort();
 156   } else {
 157     std::cerr << "ERROR: exit defined with wrong prototype!\n";
 158     abort();
 159   }
 160 }