lli.cpp revision 2f51914d828b462b054195e73c75448f24e01979 
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/JIT.h"
21#include "llvm/ExecutionEngine/Interpreter.h"
22#include "llvm/ExecutionEngine/GenericValue.h"
23#include "llvm/Support/CommandLine.h"
24#include "llvm/Support/PluginLoader.h"
25#include "llvm/System/Signals.h"
26#include <iostream>
27
28using namespace llvm;
29
30namespace {
31  cl::opt<std::string>
32  InputFile(cl::desc("<input bytecode>"), cl::Positional, cl::init("-"));
33
34  cl::list<std::string>
35  InputArgv(cl::ConsumeAfter, cl::desc("<program arguments>..."));
36
37  cl::opt<bool> ForceInterpreter("force-interpreter",
38                                 cl::desc("Force interpretation: disable JIT"),
39                                 cl::init(false));
40  cl::opt<std::string>
41  TargetTriple("mtriple", cl::desc("Override target triple for module"));
42
43  cl::opt<std::string>
44  FakeArgv0("fake-argv0",
45            cl::desc("Override the 'argv[0]' value passed into the executing"
46                     " program"), cl::value_desc("executable"));
47}
48
49//===----------------------------------------------------------------------===//
50// main Driver function
51//
52int main(int argc, char **argv, char * const *envp) {
53  try {
54    cl::ParseCommandLineOptions(argc, argv,
55                                " llvm interpreter & dynamic compiler\n");
56    sys::PrintStackTraceOnErrorSignal();
57
58    // Load the bytecode...
59    std::string ErrorMsg;
60    ModuleProvider *MP = 0;
61    try {
62      MP = getBytecodeModuleProvider(InputFile);
63    } catch (std::string &err) {
64      std::cerr << "Error loading program '" << InputFile << "': "
65                << err << "\n";
66      exit(1);
67    }
68
69    // If we are supposed to override the target triple, do so now.
70    if (!TargetTriple.empty())
71      MP->getModule()->setTargetTriple(TargetTriple);
72
73    ExecutionEngine *EE = ExecutionEngine::create(MP, ForceInterpreter);
74    assert(EE &&"Couldn't create an ExecutionEngine, not even an interpreter?");
75
76    // If the user specifically requested an argv[0] to pass into the program,
77    // do it now.
78    if (!FakeArgv0.empty()) {
79      InputFile = FakeArgv0;
80    } else {
81      // Otherwise, if there is a .bc suffix on the executable strip it off, it
82      // might confuse the program.
83      if (InputFile.rfind(".bc") == InputFile.length() - 3)
84        InputFile.erase(InputFile.length() - 3);
85    }
86
87    // Add the module's name to the start of the vector of arguments to main().
88    InputArgv.insert(InputArgv.begin(), InputFile);
89
90    // Call the main function from M as if its signature were:
91    //   int main (int argc, char **argv, const char **envp)
92    // using the contents of Args to determine argc & argv, and the contents of
93    // EnvVars to determine envp.
94    //
95    Function *Fn = MP->getModule()->getMainFunction();
96    if (!Fn) {
97      std::cerr << "'main' function not found in module.\n";
98      return -1;
99    }
100
101    // Run static constructors.
102    EE->runStaticConstructorsDestructors(false);
103
104    // Run main.
105    int Result = EE->runFunctionAsMain(Fn, InputArgv, envp);
106
107    // Run static destructors.
108    EE->runStaticConstructorsDestructors(true);
109
110    // If the program didn't explicitly call exit, call exit now, for the
111    // program. This ensures that any atexit handlers get called correctly.
112    Function *Exit = MP->getModule()->getOrInsertFunction("exit", Type::VoidTy,
113                                                          Type::IntTy,
114                                                          (Type *)0);
115
116    std::vector<GenericValue> Args;
117    GenericValue ResultGV;
118    ResultGV.IntVal = Result;
119    Args.push_back(ResultGV);
120    EE->runFunction(Exit, Args);
121
122    std::cerr << "ERROR: exit(" << Result << ") returned!\n";
123    abort();
124  } catch (const std::string& msg) {
125    std::cerr << argv[0] << ": " << msg << "\n";
126  } catch (...) {
127    std::cerr << argv[0] << ": Unexpected unknown exception occurred.\n";
128  }
129  abort();
130}
131