lli.cpp revision d8b7aa26134d2abee777f745c32005e63dea2455 
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/Support/Process.h"
35#include "llvm/Support/Signals.h"
36#include "llvm/Support/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  cl::opt<Reloc::Model>
113  RelocModel("relocation-model",
114             cl::desc("Choose relocation model"),
115             cl::init(Reloc::Default),
116             cl::values(
117            clEnumValN(Reloc::Default, "default",
118                       "Target default relocation model"),
119            clEnumValN(Reloc::Static, "static",
120                       "Non-relocatable code"),
121            clEnumValN(Reloc::PIC_, "pic",
122                       "Fully relocatable, position independent code"),
123            clEnumValN(Reloc::DynamicNoPIC, "dynamic-no-pic",
124                       "Relocatable external references, non-relocatable code"),
125            clEnumValEnd));
126
127  cl::opt<llvm::CodeModel::Model>
128  CMModel("code-model",
129          cl::desc("Choose code model"),
130          cl::init(CodeModel::JITDefault),
131          cl::values(clEnumValN(CodeModel::JITDefault, "default",
132                                "Target default JIT code model"),
133                     clEnumValN(CodeModel::Small, "small",
134                                "Small code model"),
135                     clEnumValN(CodeModel::Kernel, "kernel",
136                                "Kernel code model"),
137                     clEnumValN(CodeModel::Medium, "medium",
138                                "Medium code model"),
139                     clEnumValN(CodeModel::Large, "large",
140                                "Large code model"),
141                     clEnumValEnd));
142
143}
144
145static ExecutionEngine *EE = 0;
146
147static void do_shutdown() {
148  // Cygwin-1.5 invokes DLL's dtors before atexit handler.
149#ifndef DO_NOTHING_ATEXIT
150  delete EE;
151  llvm_shutdown();
152#endif
153}
154
155//===----------------------------------------------------------------------===//
156// main Driver function
157//
158int main(int argc, char **argv, char * const *envp) {
159  sys::PrintStackTraceOnErrorSignal();
160  PrettyStackTraceProgram X(argc, argv);
161
162  LLVMContext &Context = getGlobalContext();
163  atexit(do_shutdown);  // Call llvm_shutdown() on exit.
164
165  // If we have a native target, initialize it to ensure it is linked in and
166  // usable by the JIT.
167  InitializeNativeTarget();
168  InitializeNativeTargetAsmPrinter();
169
170  cl::ParseCommandLineOptions(argc, argv,
171                              "llvm interpreter & dynamic compiler\n");
172
173  // If the user doesn't want core files, disable them.
174  if (DisableCoreFiles)
175    sys::Process::PreventCoreFiles();
176
177  // Load the bitcode...
178  SMDiagnostic Err;
179  Module *Mod = ParseIRFile(InputFile, Err, Context);
180  if (!Mod) {
181    Err.print(argv[0], errs());
182    return 1;
183  }
184
185  // If not jitting lazily, load the whole bitcode file eagerly too.
186  std::string ErrorMsg;
187  if (NoLazyCompilation) {
188    if (Mod->MaterializeAllPermanently(&ErrorMsg)) {
189      errs() << argv[0] << ": bitcode didn't read correctly.\n";
190      errs() << "Reason: " << ErrorMsg << "\n";
191      exit(1);
192    }
193  }
194
195  EngineBuilder builder(Mod);
196  builder.setMArch(MArch);
197  builder.setMCPU(MCPU);
198  builder.setMAttrs(MAttrs);
199  builder.setRelocationModel(RelocModel);
200  builder.setCodeModel(CMModel);
201  builder.setErrorStr(&ErrorMsg);
202  builder.setEngineKind(ForceInterpreter
203                        ? EngineKind::Interpreter
204                        : EngineKind::JIT);
205
206  // If we are supposed to override the target triple, do so now.
207  if (!TargetTriple.empty())
208    Mod->setTargetTriple(Triple::normalize(TargetTriple));
209
210  // Enable MCJIT, if desired.
211  if (UseMCJIT)
212    builder.setUseMCJIT(true);
213
214  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
215  switch (OptLevel) {
216  default:
217    errs() << argv[0] << ": invalid optimization level.\n";
218    return 1;
219  case ' ': break;
220  case '0': OLvl = CodeGenOpt::None; break;
221  case '1': OLvl = CodeGenOpt::Less; break;
222  case '2': OLvl = CodeGenOpt::Default; break;
223  case '3': OLvl = CodeGenOpt::Aggressive; break;
224  }
225  builder.setOptLevel(OLvl);
226
227  EE = builder.create();
228  if (!EE) {
229    if (!ErrorMsg.empty())
230      errs() << argv[0] << ": error creating EE: " << ErrorMsg << "\n";
231    else
232      errs() << argv[0] << ": unknown error creating EE!\n";
233    exit(1);
234  }
235
236  EE->RegisterJITEventListener(createOProfileJITEventListener());
237
238  EE->DisableLazyCompilation(NoLazyCompilation);
239
240  // If the user specifically requested an argv[0] to pass into the program,
241  // do it now.
242  if (!FakeArgv0.empty()) {
243    InputFile = FakeArgv0;
244  } else {
245    // Otherwise, if there is a .bc suffix on the executable strip it off, it
246    // might confuse the program.
247    if (StringRef(InputFile).endswith(".bc"))
248      InputFile.erase(InputFile.length() - 3);
249  }
250
251  // Add the module's name to the start of the vector of arguments to main().
252  InputArgv.insert(InputArgv.begin(), InputFile);
253
254  // Call the main function from M as if its signature were:
255  //   int main (int argc, char **argv, const char **envp)
256  // using the contents of Args to determine argc & argv, and the contents of
257  // EnvVars to determine envp.
258  //
259  Function *EntryFn = Mod->getFunction(EntryFunc);
260  if (!EntryFn) {
261    errs() << '\'' << EntryFunc << "\' function not found in module.\n";
262    return -1;
263  }
264
265  // If the program doesn't explicitly call exit, we will need the Exit
266  // function later on to make an explicit call, so get the function now.
267  Constant *Exit = Mod->getOrInsertFunction("exit", Type::getVoidTy(Context),
268                                                    Type::getInt32Ty(Context),
269                                                    NULL);
270
271  // Reset errno to zero on entry to main.
272  errno = 0;
273
274  // Run static constructors.
275  EE->runStaticConstructorsDestructors(false);
276
277  if (NoLazyCompilation) {
278    for (Module::iterator I = Mod->begin(), E = Mod->end(); I != E; ++I) {
279      Function *Fn = &*I;
280      if (Fn != EntryFn && !Fn->isDeclaration())
281        EE->getPointerToFunction(Fn);
282    }
283  }
284
285  // Run main.
286  int Result = EE->runFunctionAsMain(EntryFn, InputArgv, envp);
287
288  // Run static destructors.
289  EE->runStaticConstructorsDestructors(true);
290
291  // If the program didn't call exit explicitly, we should call it now.
292  // This ensures that any atexit handlers get called correctly.
293  if (Function *ExitF = dyn_cast<Function>(Exit)) {
294    std::vector<GenericValue> Args;
295    GenericValue ResultGV;
296    ResultGV.IntVal = APInt(32, Result);
297    Args.push_back(ResultGV);
298    EE->runFunction(ExitF, Args);
299    errs() << "ERROR: exit(" << Result << ") returned!\n";
300    abort();
301  } else {
302    errs() << "ERROR: exit defined with wrong prototype!\n";
303    abort();
304  }
305}
306