lli.cpp revision 6aec29848676494867e26307698155bc2c5a4033 
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/Type.h"
19#include "llvm/ADT/Triple.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/ExecutionEngine/MCJIT.h"
27#include "llvm/Support/CommandLine.h"
28#include "llvm/Support/IRReader.h"
29#include "llvm/Support/ManagedStatic.h"
30#include "llvm/Support/MemoryBuffer.h"
31#include "llvm/Support/PluginLoader.h"
32#include "llvm/Support/PrettyStackTrace.h"
33#include "llvm/Support/raw_ostream.h"
34#include "llvm/System/Process.h"
35#include "llvm/System/Signals.h"
36#include "llvm/Target/TargetSelect.h"
37#include <cerrno>
38
39#ifdef __CYGWIN__
40#include <cygwin/version.h>
41#if defined(CYGWIN_VERSION_DLL_MAJOR) && CYGWIN_VERSION_DLL_MAJOR<1007
42#define DO_NOTHING_ATEXIT 1
43#endif
44#endif
45
46using namespace llvm;
47
48namespace {
49  cl::opt<std::string>
50  InputFile(cl::desc("<input bitcode>"), cl::Positional, cl::init("-"));
51
52  cl::list<std::string>
53  InputArgv(cl::ConsumeAfter, cl::desc("<program arguments>..."));
54
55  cl::opt<bool> ForceInterpreter("force-interpreter",
56                                 cl::desc("Force interpretation: disable JIT"),
57                                 cl::init(false));
58
59  cl::opt<bool> UseMCJIT(
60    "use-mcjit", cl::desc("Enable use of the MC-based JIT (if available)"),
61    cl::init(false));
62
63  // Determine optimization level.
64  cl::opt<char>
65  OptLevel("O",
66           cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
67                    "(default = '-O2')"),
68           cl::Prefix,
69           cl::ZeroOrMore,
70           cl::init(' '));
71
72  cl::opt<std::string>
73  TargetTriple("mtriple", cl::desc("Override target triple for module"));
74
75  cl::opt<std::string>
76  MArch("march",
77        cl::desc("Architecture to generate assembly for (see --version)"));
78
79  cl::opt<std::string>
80  MCPU("mcpu",
81       cl::desc("Target a specific cpu type (-mcpu=help for details)"),
82       cl::value_desc("cpu-name"),
83       cl::init(""));
84
85  cl::list<std::string>
86  MAttrs("mattr",
87         cl::CommaSeparated,
88         cl::desc("Target specific attributes (-mattr=help for details)"),
89         cl::value_desc("a1,+a2,-a3,..."));
90
91  cl::opt<std::string>
92  EntryFunc("entry-function",
93            cl::desc("Specify the entry function (default = 'main') "
94                     "of the executable"),
95            cl::value_desc("function"),
96            cl::init("main"));
97
98  cl::opt<std::string>
99  FakeArgv0("fake-argv0",
100            cl::desc("Override the 'argv[0]' value passed into the executing"
101                     " program"), cl::value_desc("executable"));
102
103  cl::opt<bool>
104  DisableCoreFiles("disable-core-files", cl::Hidden,
105                   cl::desc("Disable emission of core files if possible"));
106
107  cl::opt<bool>
108  NoLazyCompilation("disable-lazy-compilation",
109                  cl::desc("Disable JIT lazy compilation"),
110                  cl::init(false));
111}
112
113static ExecutionEngine *EE = 0;
114
115static void do_shutdown() {
116  // Cygwin-1.5 invokes DLL's dtors before atexit handler.
117#ifndef DO_NOTHING_ATEXIT
118  delete EE;
119  llvm_shutdown();
120#endif
121}
122
123//===----------------------------------------------------------------------===//
124// main Driver function
125//
126int main(int argc, char **argv, char * const *envp) {
127  sys::PrintStackTraceOnErrorSignal();
128  PrettyStackTraceProgram X(argc, argv);
129
130  LLVMContext &Context = getGlobalContext();
131  atexit(do_shutdown);  // Call llvm_shutdown() on exit.
132
133  // If we have a native target, initialize it to ensure it is linked in and
134  // usable by the JIT.
135  InitializeNativeTarget();
136
137  cl::ParseCommandLineOptions(argc, argv,
138                              "llvm interpreter & dynamic compiler\n");
139
140  // If the user doesn't want core files, disable them.
141  if (DisableCoreFiles)
142    sys::Process::PreventCoreFiles();
143
144  // Load the bitcode...
145  SMDiagnostic Err;
146  Module *Mod = ParseIRFile(InputFile, Err, Context);
147  if (!Mod) {
148    Err.Print(argv[0], errs());
149    return 1;
150  }
151
152  // If not jitting lazily, load the whole bitcode file eagerly too.
153  std::string ErrorMsg;
154  if (NoLazyCompilation) {
155    if (Mod->MaterializeAllPermanently(&ErrorMsg)) {
156      errs() << argv[0] << ": bitcode didn't read correctly.\n";
157      errs() << "Reason: " << ErrorMsg << "\n";
158      exit(1);
159    }
160  }
161
162  EngineBuilder builder(Mod);
163  builder.setMArch(MArch);
164  builder.setMCPU(MCPU);
165  builder.setMAttrs(MAttrs);
166  builder.setErrorStr(&ErrorMsg);
167  builder.setEngineKind(ForceInterpreter
168                        ? EngineKind::Interpreter
169                        : EngineKind::JIT);
170
171  // If we are supposed to override the target triple, do so now.
172  if (!TargetTriple.empty())
173    Mod->setTargetTriple(Triple::normalize(TargetTriple));
174
175  // Enable MCJIT, if desired.
176  if (UseMCJIT)
177    builder.setUseMCJIT(true);
178
179  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
180  switch (OptLevel) {
181  default:
182    errs() << argv[0] << ": invalid optimization level.\n";
183    return 1;
184  case ' ': break;
185  case '0': OLvl = CodeGenOpt::None; break;
186  case '1': OLvl = CodeGenOpt::Less; break;
187  case '2': OLvl = CodeGenOpt::Default; break;
188  case '3': OLvl = CodeGenOpt::Aggressive; break;
189  }
190  builder.setOptLevel(OLvl);
191
192  EE = builder.create();
193  if (!EE) {
194    if (!ErrorMsg.empty())
195      errs() << argv[0] << ": error creating EE: " << ErrorMsg << "\n";
196    else
197      errs() << argv[0] << ": unknown error creating EE!\n";
198    exit(1);
199  }
200
201  EE->RegisterJITEventListener(createOProfileJITEventListener());
202
203  EE->DisableLazyCompilation(NoLazyCompilation);
204
205  // If the user specifically requested an argv[0] to pass into the program,
206  // do it now.
207  if (!FakeArgv0.empty()) {
208    InputFile = FakeArgv0;
209  } else {
210    // Otherwise, if there is a .bc suffix on the executable strip it off, it
211    // might confuse the program.
212    if (StringRef(InputFile).endswith(".bc"))
213      InputFile.erase(InputFile.length() - 3);
214  }
215
216  // Add the module's name to the start of the vector of arguments to main().
217  InputArgv.insert(InputArgv.begin(), InputFile);
218
219  // Call the main function from M as if its signature were:
220  //   int main (int argc, char **argv, const char **envp)
221  // using the contents of Args to determine argc & argv, and the contents of
222  // EnvVars to determine envp.
223  //
224  Function *EntryFn = Mod->getFunction(EntryFunc);
225  if (!EntryFn) {
226    errs() << '\'' << EntryFunc << "\' function not found in module.\n";
227    return -1;
228  }
229
230  // If the program doesn't explicitly call exit, we will need the Exit
231  // function later on to make an explicit call, so get the function now.
232  Constant *Exit = Mod->getOrInsertFunction("exit", Type::getVoidTy(Context),
233                                                    Type::getInt32Ty(Context),
234                                                    NULL);
235
236  // Reset errno to zero on entry to main.
237  errno = 0;
238
239  // Run static constructors.
240  EE->runStaticConstructorsDestructors(false);
241
242  if (NoLazyCompilation) {
243    for (Module::iterator I = Mod->begin(), E = Mod->end(); I != E; ++I) {
244      Function *Fn = &*I;
245      if (Fn != EntryFn && !Fn->isDeclaration())
246        EE->getPointerToFunction(Fn);
247    }
248  }
249
250  // Run main.
251  int Result = EE->runFunctionAsMain(EntryFn, InputArgv, envp);
252
253  // Run static destructors.
254  EE->runStaticConstructorsDestructors(true);
255
256  // If the program didn't call exit explicitly, we should call it now.
257  // This ensures that any atexit handlers get called correctly.
258  if (Function *ExitF = dyn_cast<Function>(Exit)) {
259    std::vector<GenericValue> Args;
260    GenericValue ResultGV;
261    ResultGV.IntVal = APInt(32, Result);
262    Args.push_back(ResultGV);
263    EE->runFunction(ExitF, Args);
264    errs() << "ERROR: exit(" << Result << ") returned!\n";
265    abort();
266  } else {
267    errs() << "ERROR: exit defined with wrong prototype!\n";
268    abort();
269  }
270}
271