lli.cpp revision db9c028d019f60c7bbb0d8282ffd14f348c0cf52 
1//===- lli.cpp - LLVM Interpreter / Dynamic compiler ----------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// 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 interpreter if no JIT is available for this platform.
13//
14//===----------------------------------------------------------------------===//
15
16#include "llvm/LLVMContext.h"
17#include "llvm/Module.h"
18#include "llvm/ModuleProvider.h"
19#include "llvm/Type.h"
20#include "llvm/Bitcode/ReaderWriter.h"
21#include "llvm/CodeGen/LinkAllCodegenComponents.h"
22#include "llvm/ExecutionEngine/GenericValue.h"
23#include "llvm/ExecutionEngine/Interpreter.h"
24#include "llvm/ExecutionEngine/JIT.h"
25#include "llvm/ExecutionEngine/JITEventListener.h"
26#include "llvm/Support/CommandLine.h"
27#include "llvm/Support/ManagedStatic.h"
28#include "llvm/Support/MemoryBuffer.h"
29#include "llvm/Support/PluginLoader.h"
30#include "llvm/Support/PrettyStackTrace.h"
31#include "llvm/System/Process.h"
32#include "llvm/System/Signals.h"
33#include "llvm/Target/TargetSelect.h"
34#include <iostream>
35#include <cerrno>
36using namespace llvm;
37
38namespace {
39  cl::opt<std::string>
40  InputFile(cl::desc("<input bitcode>"), cl::Positional, cl::init("-"));
41
42  cl::list<std::string>
43  InputArgv(cl::ConsumeAfter, cl::desc("<program arguments>..."));
44
45  cl::opt<bool> ForceInterpreter("force-interpreter",
46                                 cl::desc("Force interpretation: disable JIT"),
47                                 cl::init(false));
48
49  // Determine optimization level.
50  cl::opt<char>
51  OptLevel("O",
52           cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
53                    "(default = '-O2')"),
54           cl::Prefix,
55           cl::ZeroOrMore,
56           cl::init(' '));
57
58  cl::opt<std::string>
59  TargetTriple("mtriple", cl::desc("Override target triple for module"));
60
61  cl::opt<std::string>
62  EntryFunc("entry-function",
63            cl::desc("Specify the entry function (default = 'main') "
64                     "of the executable"),
65            cl::value_desc("function"),
66            cl::init("main"));
67
68  cl::opt<std::string>
69  FakeArgv0("fake-argv0",
70            cl::desc("Override the 'argv[0]' value passed into the executing"
71                     " program"), cl::value_desc("executable"));
72
73  cl::opt<bool>
74  DisableCoreFiles("disable-core-files", cl::Hidden,
75                   cl::desc("Disable emission of core files if possible"));
76
77  cl::opt<bool>
78  NoLazyCompilation("disable-lazy-compilation",
79                  cl::desc("Disable JIT lazy compilation"),
80                  cl::init(false));
81}
82
83static ExecutionEngine *EE = 0;
84
85static void do_shutdown() {
86  delete EE;
87  llvm_shutdown();
88}
89
90//===----------------------------------------------------------------------===//
91// main Driver function
92//
93int main(int argc, char **argv, char * const *envp) {
94  sys::PrintStackTraceOnErrorSignal();
95  PrettyStackTraceProgram X(argc, argv);
96
97  LLVMContext Context;
98  atexit(do_shutdown);  // Call llvm_shutdown() on exit.
99  cl::ParseCommandLineOptions(argc, argv,
100                              "llvm interpreter & dynamic compiler\n");
101
102  // If the user doesn't want core files, disable them.
103  if (DisableCoreFiles)
104    sys::Process::PreventCoreFiles();
105
106  // Load the bitcode...
107  std::string ErrorMsg;
108  ModuleProvider *MP = NULL;
109  if (MemoryBuffer *Buffer = MemoryBuffer::getFileOrSTDIN(InputFile,&ErrorMsg)){
110    MP = getBitcodeModuleProvider(Buffer, Context, &ErrorMsg);
111    if (!MP) delete Buffer;
112  }
113
114  if (!MP) {
115    std::cerr << argv[0] << ": error loading program '" << InputFile << "': "
116              << ErrorMsg << "\n";
117    exit(1);
118  }
119
120  // Get the module as the MP could go away once EE takes over.
121  Module *Mod = NoLazyCompilation
122    ? MP->materializeModule(&ErrorMsg) : MP->getModule();
123  if (!Mod) {
124    std::cerr << argv[0] << ": bitcode didn't read correctly.\n";
125    std::cerr << "Reason: " << ErrorMsg << "\n";
126    exit(1);
127  }
128
129  // If we are supposed to override the target triple, do so now.
130  if (!TargetTriple.empty())
131    Mod->setTargetTriple(TargetTriple);
132
133  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
134  switch (OptLevel) {
135  default:
136    std::cerr << argv[0] << ": invalid optimization level.\n";
137    return 1;
138  case ' ': break;
139  case '0': OLvl = CodeGenOpt::None; break;
140  case '1':
141  case '2': OLvl = CodeGenOpt::Default; break;
142  case '3': OLvl = CodeGenOpt::Aggressive; break;
143  }
144
145  // If we have a native target, initialize it to ensure it is linked in and
146  // usable by the JIT.
147  InitializeNativeTarget();
148
149  EE = ExecutionEngine::create(MP, ForceInterpreter, &ErrorMsg, OLvl);
150  if (!EE && !ErrorMsg.empty()) {
151    std::cerr << argv[0] << ":error creating EE: " << ErrorMsg << "\n";
152    exit(1);
153  }
154
155  EE->RegisterJITEventListener(createMacOSJITEventListener());
156
157  if (NoLazyCompilation)
158    EE->DisableLazyCompilation();
159
160  // If the user specifically requested an argv[0] to pass into the program,
161  // do it now.
162  if (!FakeArgv0.empty()) {
163    InputFile = FakeArgv0;
164  } else {
165    // Otherwise, if there is a .bc suffix on the executable strip it off, it
166    // might confuse the program.
167    if (InputFile.rfind(".bc") == InputFile.length() - 3)
168      InputFile.erase(InputFile.length() - 3);
169  }
170
171  // Add the module's name to the start of the vector of arguments to main().
172  InputArgv.insert(InputArgv.begin(), InputFile);
173
174  // Call the main function from M as if its signature were:
175  //   int main (int argc, char **argv, const char **envp)
176  // using the contents of Args to determine argc & argv, and the contents of
177  // EnvVars to determine envp.
178  //
179  Function *EntryFn = Mod->getFunction(EntryFunc);
180  if (!EntryFn) {
181    std::cerr << '\'' << EntryFunc << "\' function not found in module.\n";
182    return -1;
183  }
184
185  // If the program doesn't explicitly call exit, we will need the Exit
186  // function later on to make an explicit call, so get the function now.
187  Constant *Exit = Mod->getOrInsertFunction("exit", Type::VoidTy,
188                                                        Type::Int32Ty, NULL);
189
190  // Reset errno to zero on entry to main.
191  errno = 0;
192
193  // Run static constructors.
194  EE->runStaticConstructorsDestructors(false);
195
196  if (NoLazyCompilation) {
197    for (Module::iterator I = Mod->begin(), E = Mod->end(); I != E; ++I) {
198      Function *Fn = &*I;
199      if (Fn != EntryFn && !Fn->isDeclaration())
200        EE->getPointerToFunction(Fn);
201    }
202  }
203
204  // Run main.
205  int Result = EE->runFunctionAsMain(EntryFn, InputArgv, envp);
206
207  // Run static destructors.
208  EE->runStaticConstructorsDestructors(true);
209
210  // If the program didn't call exit explicitly, we should call it now.
211  // This ensures that any atexit handlers get called correctly.
212  if (Function *ExitF = dyn_cast<Function>(Exit)) {
213    std::vector<GenericValue> Args;
214    GenericValue ResultGV;
215    ResultGV.IntVal = APInt(32, Result);
216    Args.push_back(ResultGV);
217    EE->runFunction(ExitF, Args);
218    std::cerr << "ERROR: exit(" << Result << ") returned!\n";
219    abort();
220  } else {
221    std::cerr << "ERROR: exit defined with wrong prototype!\n";
222    abort();
223  }
224}
225