lli.cpp revision bed85ff010b95923646ed4e187a5d432cedf67da 
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#include "llvm/System/Signals.h"
24
25using namespace llvm;
26
27namespace {
28  cl::opt<std::string>
29  InputFile(cl::desc("<input bytecode>"), cl::Positional, cl::init("-"));
30
31  cl::list<std::string>
32  InputArgv(cl::ConsumeAfter, cl::desc("<program arguments>..."));
33
34  cl::opt<bool> ForceInterpreter("force-interpreter",
35                                 cl::desc("Force interpretation: disable JIT"),
36                                 cl::init(false));
37
38  cl::opt<std::string>
39  FakeArgv0("fake-argv0",
40            cl::desc("Override the 'argv[0]' value passed into the executing"
41                     " program"), cl::value_desc("executable"));
42}
43
44//===----------------------------------------------------------------------===//
45// main Driver function
46//
47int main(int argc, char **argv, char * const *envp) {
48  cl::ParseCommandLineOptions(argc, argv,
49                              " llvm interpreter & dynamic compiler\n");
50  PrintStackTraceOnErrorSignal();
51
52  // Load the bytecode...
53  std::string ErrorMsg;
54  ModuleProvider *MP = 0;
55  try {
56    MP = getBytecodeModuleProvider(InputFile);
57  } catch (std::string &err) {
58    std::cerr << "Error loading program '" << InputFile << "': " << err << "\n";
59    exit(1);
60  }
61
62  ExecutionEngine *EE = ExecutionEngine::create(MP, ForceInterpreter);
63  assert(EE && "Couldn't create an ExecutionEngine, not even an interpreter?");
64
65  // If the user specifically requested an argv[0] to pass into the program, do
66  // it now.
67  if (!FakeArgv0.empty()) {
68    InputFile = FakeArgv0;
69  } else {
70    // Otherwise, if there is a .bc suffix on the executable strip it off, it
71    // might confuse the program.
72    if (InputFile.rfind(".bc") == InputFile.length() - 3)
73      InputFile.erase(InputFile.length() - 3);
74  }
75
76  // Add the module's name to the start of the vector of arguments to main().
77  InputArgv.insert(InputArgv.begin(), InputFile);
78
79  // Call the main function from M as if its signature were:
80  //   int main (int argc, char **argv, const char **envp)
81  // using the contents of Args to determine argc & argv, and the contents of
82  // EnvVars to determine envp.
83  //
84  Function *Fn = MP->getModule()->getMainFunction();
85  if (!Fn) {
86    std::cerr << "'main' function not found in module.\n";
87    return -1;
88  }
89
90  // Run main...
91  int Result = EE->runFunctionAsMain(Fn, InputArgv, envp);
92
93  // If the program didn't explicitly call exit, call exit now, for the program.
94  // This ensures that any atexit handlers get called correctly.
95  Function *Exit = MP->getModule()->getOrInsertFunction("exit", Type::VoidTy,
96                                                        Type::IntTy, 0);
97
98  std::vector<GenericValue> Args;
99  GenericValue ResultGV;
100  ResultGV.IntVal = Result;
101  Args.push_back(ResultGV);
102  EE->runFunction(Exit, Args);
103
104  std::cerr << "ERROR: exit(" << Result << ") returned!\n";
105  abort();
106}
107