lli.cpp revision 269a42811bf20f17a69600905cc5c03f68773043 
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/Bytecode/Reader.h"
20#include "llvm/ExecutionEngine/ExecutionEngine.h"
21#include "llvm/ExecutionEngine/GenericValue.h"
22#include "Support/CommandLine.h"
23
24using namespace llvm;
25
26namespace {
27  cl::opt<std::string>
28  InputFile(cl::desc("<input bytecode>"), cl::Positional, cl::init("-"));
29
30  cl::list<std::string>
31  InputArgv(cl::ConsumeAfter, cl::desc("<program arguments>..."));
32
33  cl::opt<bool> ForceInterpreter("force-interpreter",
34                                 cl::desc("Force interpretation: disable JIT"),
35                                 cl::init(false));
36
37  cl::opt<std::string>
38  FakeArgv0("fake-argv0",
39            cl::desc("Override the 'argv[0]' value passed into the executing"
40                     " program"), cl::value_desc("executable"));
41}
42
43//===----------------------------------------------------------------------===//
44// main Driver function
45//
46int main(int argc, char **argv, char * const *envp) {
47  cl::ParseCommandLineOptions(argc, argv,
48                              " llvm interpreter & dynamic compiler\n");
49
50  // Load the bytecode...
51  std::string ErrorMsg;
52  ModuleProvider *MP = 0;
53  try {
54    MP = getBytecodeModuleProvider(InputFile);
55  } catch (std::string &err) {
56    std::cerr << "Error loading program '" << InputFile << "': " << err << "\n";
57    exit(1);
58  }
59
60  ExecutionEngine *EE =
61    ExecutionEngine::create(MP, ForceInterpreter);
62  assert(EE && "Couldn't create an ExecutionEngine, not even an interpreter?");
63
64  // If the user specifically requested an argv[0] to pass into the program, do
65  // it now.
66  if (!FakeArgv0.empty()) {
67    InputFile = FakeArgv0;
68  } else {
69    // Otherwise, if there is a .bc suffix on the executable strip it off, it
70    // might confuse the program.
71    if (InputFile.rfind(".bc") == InputFile.length() - 3)
72      InputFile.erase(InputFile.length() - 3);
73  }
74
75  // Add the module's name to the start of the vector of arguments to main().
76  InputArgv.insert(InputArgv.begin(), InputFile);
77
78  // Call the main function from M as if its signature were:
79  //   int main (int argc, char **argv, const char **envp)
80  // using the contents of Args to determine argc & argv, and the contents of
81  // EnvVars to determine envp.
82  //
83  Function *Fn = MP->getModule()->getMainFunction();
84  if (!Fn) {
85    std::cerr << "'main' function not found in module.\n";
86    return -1;
87  }
88
89  // Run main...
90  int Result = EE->runFunctionAsMain(Fn, InputArgv, envp);
91
92  // If the program didn't explicitly call exit, call exit now, for the program.
93  // This ensures that any atexit handlers get called correctly.
94  Function *Exit = MP->getModule()->getOrInsertFunction("exit", Type::VoidTy,
95                                                        Type::IntTy, 0);
96
97  std::vector<GenericValue> Args;
98  GenericValue ResultGV;
99  ResultGV.IntVal = Result;
100  Args.push_back(ResultGV);
101  EE->runFunction(Exit, Args);
102
103  std::cerr << "ERROR: exit(" << Result << ") returned!\n";
104  abort();
105}
106