lli.cpp revision 020403209a86a3b4d210a4bc62b37ee5cf49dec8 
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/CodeGen/LinkAllCodegenComponents.h"
21#include "llvm/ExecutionEngine/JIT.h"
22#include "llvm/ExecutionEngine/Interpreter.h"
23#include "llvm/ExecutionEngine/GenericValue.h"
24#include "llvm/Support/CommandLine.h"
25#include "llvm/Support/Compressor.h"
26#include "llvm/Support/ManagedStatic.h"
27#include "llvm/Support/PluginLoader.h"
28#include "llvm/System/Process.h"
29#include "llvm/System/Signals.h"
30#include <iostream>
31#include <cerrno>
32using namespace llvm;
33
34namespace {
35  cl::opt<std::string>
36  InputFile(cl::desc("<input bytecode>"), cl::Positional, cl::init("-"));
37
38  cl::list<std::string>
39  InputArgv(cl::ConsumeAfter, cl::desc("<program arguments>..."));
40
41  cl::opt<bool> ForceInterpreter("force-interpreter",
42                                 cl::desc("Force interpretation: disable JIT"),
43                                 cl::init(false));
44  cl::opt<std::string>
45  TargetTriple("mtriple", cl::desc("Override target triple for module"));
46
47  cl::opt<std::string>
48  FakeArgv0("fake-argv0",
49            cl::desc("Override the 'argv[0]' value passed into the executing"
50                     " program"), cl::value_desc("executable"));
51
52  cl::opt<bool>
53  DisableCoreFiles("disable-core-files", cl::Hidden,
54                   cl::desc("Disable emission of core files if possible"));
55}
56
57static ExecutionEngine *EE = 0;
58
59static void do_shutdown() {
60  delete EE;
61  llvm_shutdown();
62}
63
64//===----------------------------------------------------------------------===//
65// main Driver function
66//
67int main(int argc, char **argv, char * const *envp) {
68  atexit(do_shutdown);  // Call llvm_shutdown() on exit.
69  try {
70    cl::ParseCommandLineOptions(argc, argv,
71                                " llvm interpreter & dynamic compiler\n");
72    sys::PrintStackTraceOnErrorSignal();
73
74    // If the user doesn't want core files, disable them.
75    if (DisableCoreFiles)
76      sys::Process::PreventCoreFiles();
77
78    // Load the bytecode...
79    std::string ErrorMsg;
80    ModuleProvider *MP = getBytecodeModuleProvider(InputFile,
81                                              Compressor::decompressToNewBuffer,
82                                              &ErrorMsg);
83    if (!MP) {
84      std::cerr << argv[0] << ": error loading program '" << InputFile << "': "
85                << ErrorMsg << "\n";
86      exit(1);
87    }
88
89    // Get the module as the MP could go away once EE takes over.
90    Module *Mod = MP->getModule();
91
92    // If we are supposed to override the target triple, do so now.
93    if (!TargetTriple.empty())
94      Mod->setTargetTriple(TargetTriple);
95
96    EE = ExecutionEngine::create(MP, ForceInterpreter, &ErrorMsg);
97    if (!EE && !ErrorMsg.empty()) {
98      std::cerr << argv[0] << ":error creating EE: " << ErrorMsg << "\n";
99      exit(1);
100    }
101
102    // If the user specifically requested an argv[0] to pass into the program,
103    // do it now.
104    if (!FakeArgv0.empty()) {
105      InputFile = FakeArgv0;
106    } else {
107      // Otherwise, if there is a .bc suffix on the executable strip it off, it
108      // might confuse the program.
109      if (InputFile.rfind(".bc") == InputFile.length() - 3)
110        InputFile.erase(InputFile.length() - 3);
111    }
112
113    // Add the module's name to the start of the vector of arguments to main().
114    InputArgv.insert(InputArgv.begin(), InputFile);
115
116    // Call the main function from M as if its signature were:
117    //   int main (int argc, char **argv, const char **envp)
118    // using the contents of Args to determine argc & argv, and the contents of
119    // EnvVars to determine envp.
120    //
121    Function *Fn = Mod->getFunction("main");
122    if (!Fn) {
123      std::cerr << "'main' function not found in module.\n";
124      return -1;
125    }
126
127    // If the program doesn't explicitly call exit, we will need the Exit
128    // function later on to make an explicit call, so get the function now.
129    Constant *Exit = Mod->getOrInsertFunction("exit", Type::VoidTy,
130                                                          Type::Int32Ty, NULL);
131
132    // Reset errno to zero on entry to main.
133    errno = 0;
134
135    // Run static constructors.
136    EE->runStaticConstructorsDestructors(false);
137
138    // Run main.
139    int Result = EE->runFunctionAsMain(Fn, InputArgv, envp);
140
141    // Run static destructors.
142    EE->runStaticConstructorsDestructors(true);
143
144    // If the program didn't call exit explicitly, we should call it now.
145    // This ensures that any atexit handlers get called correctly.
146    if (Function *ExitF = dyn_cast<Function>(Exit)) {
147      std::vector<GenericValue> Args;
148      GenericValue ResultGV;
149      ResultGV.IntVal = APInt(32, Result);
150      Args.push_back(ResultGV);
151      EE->runFunction(ExitF, Args);
152      std::cerr << "ERROR: exit(" << Result << ") returned!\n";
153      abort();
154    } else {
155      std::cerr << "ERROR: exit defined with wrong prototype!\n";
156      abort();
157    }
158  } catch (const std::string& msg) {
159    std::cerr << argv[0] << ": " << msg << "\n";
160  } catch (...) {
161    std::cerr << argv[0] << ": Unexpected unknown exception occurred.\n";
162  }
163  abort();
164}
165