lli.cpp revision 66c5fd6c537269eaef0f630fa14360dcaff6a295 
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 "llvm/Support/CommandLine.h"
23#include "llvm/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  try {
51    cl::ParseCommandLineOptions(argc, argv,
52                                " llvm interpreter & dynamic compiler\n");
53    sys::PrintStackTraceOnErrorSignal();
54
55    // Load the bytecode...
56    std::string ErrorMsg;
57    ModuleProvider *MP = 0;
58    try {
59      MP = getBytecodeModuleProvider(InputFile);
60    } catch (std::string &err) {
61      std::cerr << "Error loading program '" << InputFile << "': " << err << "\n";
62      exit(1);
63    }
64
65    ExecutionEngine *EE = ExecutionEngine::create(MP, ForceInterpreter);
66    assert(EE && "Couldn't create an ExecutionEngine, not even an interpreter?");
67
68    // If the user specifically requested an argv[0] to pass into the program, do
69    // it now.
70    if (!FakeArgv0.empty()) {
71      InputFile = FakeArgv0;
72    } else {
73      // Otherwise, if there is a .bc suffix on the executable strip it off, it
74      // might confuse the program.
75      if (InputFile.rfind(".bc") == InputFile.length() - 3)
76        InputFile.erase(InputFile.length() - 3);
77    }
78
79    // Add the module's name to the start of the vector of arguments to main().
80    InputArgv.insert(InputArgv.begin(), InputFile);
81
82    // Call the main function from M as if its signature were:
83    //   int main (int argc, char **argv, const char **envp)
84    // using the contents of Args to determine argc & argv, and the contents of
85    // EnvVars to determine envp.
86    //
87    Function *Fn = MP->getModule()->getMainFunction();
88    if (!Fn) {
89      std::cerr << "'main' function not found in module.\n";
90      return -1;
91    }
92
93    // Run main...
94    int Result = EE->runFunctionAsMain(Fn, InputArgv, envp);
95
96    // If the program didn't explicitly call exit, call exit now, for the program.
97    // This ensures that any atexit handlers get called correctly.
98    Function *Exit = MP->getModule()->getOrInsertFunction("exit", Type::VoidTy,
99                                                          Type::IntTy,
100                                                          (Type *)0);
101
102    std::vector<GenericValue> Args;
103    GenericValue ResultGV;
104    ResultGV.IntVal = Result;
105    Args.push_back(ResultGV);
106    EE->runFunction(Exit, Args);
107
108    std::cerr << "ERROR: exit(" << Result << ") returned!\n";
109    abort();
110  } catch (const std::string& msg) {
111    std::cerr << argv[0] << ": " << msg << "\n";
112  } catch (...) {
113    std::cerr << argv[0] << ": Unexpected unknown exception occurred.\n";
114  }
115  abort();
116}
117