lli.cpp revision 195098 
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 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/Bitcode/ReaderWriter.h"
20#include "llvm/CodeGen/LinkAllCodegenComponents.h"
21#include "llvm/ExecutionEngine/GenericValue.h"
22#include "llvm/ExecutionEngine/Interpreter.h"
23#include "llvm/ExecutionEngine/JIT.h"
24#include "llvm/ExecutionEngine/JITEventListener.h"
25#include "llvm/Support/CommandLine.h"
26#include "llvm/Support/ManagedStatic.h"
27#include "llvm/Support/MemoryBuffer.h"
28#include "llvm/Support/PluginLoader.h"
29#include "llvm/Support/PrettyStackTrace.h"
30#include "llvm/System/Process.h"
31#include "llvm/System/Signals.h"
32#include "llvm/Target/TargetSelect.h"
33#include <iostream>
34#include <cerrno>
35using namespace llvm;
36
37namespace {
38  cl::opt<std::string>
39  InputFile(cl::desc("<input bitcode>"), cl::Positional, cl::init("-"));
40
41  cl::list<std::string>
42  InputArgv(cl::ConsumeAfter, cl::desc("<program arguments>..."));
43
44  cl::opt<bool> ForceInterpreter("force-interpreter",
45                                 cl::desc("Force interpretation: disable JIT"),
46                                 cl::init(false));
47
48  // Determine optimization level.
49  cl::opt<char>
50  OptLevel("O",
51           cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
52                    "(default = '-O2')"),
53           cl::Prefix,
54           cl::ZeroOrMore,
55           cl::init(' '));
56
57  cl::opt<std::string>
58  TargetTriple("mtriple", cl::desc("Override target triple for module"));
59
60  cl::opt<std::string>
61  EntryFunc("entry-function",
62            cl::desc("Specify the entry function (default = 'main') "
63                     "of the executable"),
64            cl::value_desc("function"),
65            cl::init("main"));
66
67  cl::opt<std::string>
68  FakeArgv0("fake-argv0",
69            cl::desc("Override the 'argv[0]' value passed into the executing"
70                     " program"), cl::value_desc("executable"));
71
72  cl::opt<bool>
73  DisableCoreFiles("disable-core-files", cl::Hidden,
74                   cl::desc("Disable emission of core files if possible"));
75
76  cl::opt<bool>
77  NoLazyCompilation("disable-lazy-compilation",
78                  cl::desc("Disable JIT lazy compilation"),
79                  cl::init(false));
80}
81
82static ExecutionEngine *EE = 0;
83
84static void do_shutdown() {
85  delete EE;
86  llvm_shutdown();
87}
88
89//===----------------------------------------------------------------------===//
90// main Driver function
91//
92int main(int argc, char **argv, char * const *envp) {
93  sys::PrintStackTraceOnErrorSignal();
94  PrettyStackTraceProgram X(argc, argv);
95
96  atexit(do_shutdown);  // Call llvm_shutdown() on exit.
97  cl::ParseCommandLineOptions(argc, argv,
98                              "llvm interpreter & dynamic compiler\n");
99
100  // If the user doesn't want core files, disable them.
101  if (DisableCoreFiles)
102    sys::Process::PreventCoreFiles();
103
104  // Load the bitcode...
105  std::string ErrorMsg;
106  ModuleProvider *MP = NULL;
107  if (MemoryBuffer *Buffer = MemoryBuffer::getFileOrSTDIN(InputFile,&ErrorMsg)) {
108    MP = getBitcodeModuleProvider(Buffer, &ErrorMsg);
109    if (!MP) delete Buffer;
110  }
111
112  if (!MP) {
113    std::cerr << argv[0] << ": error loading program '" << InputFile << "': "
114              << ErrorMsg << "\n";
115    exit(1);
116  }
117
118  // Get the module as the MP could go away once EE takes over.
119  Module *Mod = NoLazyCompilation
120    ? MP->materializeModule(&ErrorMsg) : MP->getModule();
121  if (!Mod) {
122    std::cerr << argv[0] << ": bitcode didn't read correctly.\n";
123    std::cerr << "Reason: " << ErrorMsg << "\n";
124    exit(1);
125  }
126
127  // If we are supposed to override the target triple, do so now.
128  if (!TargetTriple.empty())
129    Mod->setTargetTriple(TargetTriple);
130
131  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
132  switch (OptLevel) {
133  default:
134    std::cerr << argv[0] << ": invalid optimization level.\n";
135    return 1;
136  case ' ': break;
137  case '0': OLvl = CodeGenOpt::None; break;
138  case '1':
139  case '2': OLvl = CodeGenOpt::Default; break;
140  case '3': OLvl = CodeGenOpt::Aggressive; break;
141  }
142
143  // If we have a native target, initialize it to ensure it is linked in and
144  // usable by the JIT.
145  InitializeNativeTarget();
146
147  EE = ExecutionEngine::create(MP, ForceInterpreter, &ErrorMsg, OLvl);
148  if (!EE && !ErrorMsg.empty()) {
149    std::cerr << argv[0] << ":error creating EE: " << ErrorMsg << "\n";
150    exit(1);
151  }
152
153  EE->RegisterJITEventListener(createMacOSJITEventListener());
154
155  if (NoLazyCompilation)
156    EE->DisableLazyCompilation();
157
158  // If the user specifically requested an argv[0] to pass into the program,
159  // do it now.
160  if (!FakeArgv0.empty()) {
161    InputFile = FakeArgv0;
162  } else {
163    // Otherwise, if there is a .bc suffix on the executable strip it off, it
164    // might confuse the program.
165    if (InputFile.rfind(".bc") == InputFile.length() - 3)
166      InputFile.erase(InputFile.length() - 3);
167  }
168
169  // Add the module's name to the start of the vector of arguments to main().
170  InputArgv.insert(InputArgv.begin(), InputFile);
171
172  // Call the main function from M as if its signature were:
173  //   int main (int argc, char **argv, const char **envp)
174  // using the contents of Args to determine argc & argv, and the contents of
175  // EnvVars to determine envp.
176  //
177  Function *EntryFn = Mod->getFunction(EntryFunc);
178  if (!EntryFn) {
179    std::cerr << '\'' << EntryFunc << "\' function not found in module.\n";
180    return -1;
181  }
182
183  // If the program doesn't explicitly call exit, we will need the Exit
184  // function later on to make an explicit call, so get the function now.
185  Constant *Exit = Mod->getOrInsertFunction("exit", Type::VoidTy,
186                                                        Type::Int32Ty, NULL);
187
188  // Reset errno to zero on entry to main.
189  errno = 0;
190
191  // Run static constructors.
192  EE->runStaticConstructorsDestructors(false);
193
194  if (NoLazyCompilation) {
195    for (Module::iterator I = Mod->begin(), E = Mod->end(); I != E; ++I) {
196      Function *Fn = &*I;
197      if (Fn != EntryFn && !Fn->isDeclaration())
198        EE->getPointerToFunction(Fn);
199    }
200  }
201
202  // Run main.
203  int Result = EE->runFunctionAsMain(EntryFn, InputArgv, envp);
204
205  // Run static destructors.
206  EE->runStaticConstructorsDestructors(true);
207
208  // If the program didn't call exit explicitly, we should call it now.
209  // This ensures that any atexit handlers get called correctly.
210  if (Function *ExitF = dyn_cast<Function>(Exit)) {
211    std::vector<GenericValue> Args;
212    GenericValue ResultGV;
213    ResultGV.IntVal = APInt(32, Result);
214    Args.push_back(ResultGV);
215    EE->runFunction(ExitF, Args);
216    std::cerr << "ERROR: exit(" << Result << ") returned!\n";
217    abort();
218  } else {
219    std::cerr << "ERROR: exit defined with wrong prototype!\n";
220    abort();
221  }
222}
223