lli.cpp revision a3eb7b3983492a8f5b365d100b69771f06a72e73 
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 "Support/PluginLoader.h"
24#include "llvm/System/Signals.h"
25#include <iostream>
26
27using namespace llvm;
28
29namespace {
30  cl::opt<std::string>
31  InputFile(cl::desc("<input bytecode>"), cl::Positional, cl::init("-"));
32
33  cl::list<std::string>
34  InputArgv(cl::ConsumeAfter, cl::desc("<program arguments>..."));
35
36  cl::opt<bool> ForceInterpreter("force-interpreter",
37                                 cl::desc("Force interpretation: disable JIT"),
38                                 cl::init(false));
39
40  cl::opt<std::string>
41  FakeArgv0("fake-argv0",
42            cl::desc("Override the 'argv[0]' value passed into the executing"
43                     " program"), cl::value_desc("executable"));
44}
45
46//===----------------------------------------------------------------------===//
47// main Driver function
48//
49int main(int argc, char **argv, char * const *envp) {
50  cl::ParseCommandLineOptions(argc, argv,
51                              " llvm interpreter & dynamic compiler\n");
52  PrintStackTraceOnErrorSignal();
53
54  // Load the bytecode...
55  std::string ErrorMsg;
56  ModuleProvider *MP = 0;
57  try {
58    MP = getBytecodeModuleProvider(InputFile);
59  } catch (std::string &err) {
60    std::cerr << "Error loading program '" << InputFile << "': " << err << "\n";
61    exit(1);
62  }
63
64  ExecutionEngine *EE = ExecutionEngine::create(MP, ForceInterpreter);
65  assert(EE && "Couldn't create an ExecutionEngine, not even an interpreter?");
66
67  // If the user specifically requested an argv[0] to pass into the program, do
68  // it now.
69  if (!FakeArgv0.empty()) {
70    InputFile = FakeArgv0;
71  } else {
72    // Otherwise, if there is a .bc suffix on the executable strip it off, it
73    // might confuse the program.
74    if (InputFile.rfind(".bc") == InputFile.length() - 3)
75      InputFile.erase(InputFile.length() - 3);
76  }
77
78  // Add the module's name to the start of the vector of arguments to main().
79  InputArgv.insert(InputArgv.begin(), InputFile);
80
81  // Call the main function from M as if its signature were:
82  //   int main (int argc, char **argv, const char **envp)
83  // using the contents of Args to determine argc & argv, and the contents of
84  // EnvVars to determine envp.
85  //
86  Function *Fn = MP->getModule()->getMainFunction();
87  if (!Fn) {
88    std::cerr << "'main' function not found in module.\n";
89    return -1;
90  }
91
92  // Run main...
93  int Result = EE->runFunctionAsMain(Fn, InputArgv, envp);
94
95  // If the program didn't explicitly call exit, call exit now, for the program.
96  // This ensures that any atexit handlers get called correctly.
97  Function *Exit = MP->getModule()->getOrInsertFunction("exit", Type::VoidTy,
98                                                        Type::IntTy, 0);
99
100  std::vector<GenericValue> Args;
101  GenericValue ResultGV;
102  ResultGV.IntVal = Result;
103  Args.push_back(ResultGV);
104  EE->runFunction(Exit, Args);
105
106  std::cerr << "ERROR: exit(" << Result << ") returned!\n";
107  abort();
108}
109