lli.cpp revision 7efea1dd98cd9e20ef160c838190f5249123f494 
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/DerivedTypes.h"
17#include "llvm/Module.h"
18#include "llvm/ModuleProvider.h"
19#include "llvm/Bytecode/Reader.h"
20#include "llvm/ExecutionEngine/ExecutionEngine.h"
21#include "llvm/ExecutionEngine/GenericValue.h"
22#include "llvm/Target/TargetMachineImpls.h"
23#include "llvm/Target/TargetData.h"
24#include "Support/CommandLine.h"
25#include "Support/Debug.h"
26#include "Support/SystemUtils.h"
27
28using namespace llvm;
29
30namespace {
31  cl::opt<std::string>
32  InputFile(cl::desc("<input bytecode>"), cl::Positional, cl::init("-"));
33
34  cl::list<std::string>
35  InputArgv(cl::ConsumeAfter, cl::desc("<program arguments>..."));
36
37  cl::opt<std::string>
38  MainFunction("f", cl::desc("Function to execute"), cl::init("main"),
39               cl::value_desc("function name"));
40
41  cl::opt<bool> ForceInterpreter("force-interpreter",
42                                 cl::desc("Force interpretation: disable JIT"),
43                                 cl::init(false));
44
45  cl::opt<std::string>
46  FakeArgv0("fake-argv0",
47            cl::desc("Override the 'argv[0]' value passed into the executing"
48                     " program"), cl::value_desc("executable"));
49}
50
51static std::vector<std::string> makeStringVector(char * const *envp) {
52  std::vector<std::string> rv;
53  for (unsigned i = 0; envp[i]; ++i)
54    rv.push_back(envp[i]);
55  return rv;
56}
57
58static void *CreateArgv(ExecutionEngine *EE,
59                        const std::vector<std::string> &InputArgv) {
60  if (EE->getTargetData().getPointerSize() == 8) {   // 64 bit target?
61    PointerTy *Result = new PointerTy[InputArgv.size()+1];
62    DEBUG(std::cerr << "ARGV = " << (void*)Result << "\n");
63
64    for (unsigned i = 0; i < InputArgv.size(); ++i) {
65      unsigned Size = InputArgv[i].size()+1;
66      char *Dest = new char[Size];
67      DEBUG(std::cerr << "ARGV[" << i << "] = " << (void*)Dest << "\n");
68
69      std::copy(InputArgv[i].begin(), InputArgv[i].end(), Dest);
70      Dest[Size-1] = 0;
71
72      // Endian safe: Result[i] = (PointerTy)Dest;
73      EE->StoreValueToMemory(PTOGV(Dest), (GenericValue*)(Result+i),
74                             Type::LongTy);
75    }
76    Result[InputArgv.size()] = 0;
77    return Result;
78  } else {                                      // 32 bit target?
79    int *Result = new int[InputArgv.size()+1];
80    DEBUG(std::cerr << "ARGV = " << (void*)Result << "\n");
81
82    for (unsigned i = 0; i < InputArgv.size(); ++i) {
83      unsigned Size = InputArgv[i].size()+1;
84      char *Dest = new char[Size];
85      DEBUG(std::cerr << "ARGV[" << i << "] = " << (void*)Dest << "\n");
86
87      std::copy(InputArgv[i].begin(), InputArgv[i].end(), Dest);
88      Dest[Size-1] = 0;
89
90      // Endian safe: Result[i] = (PointerTy)Dest;
91      EE->StoreValueToMemory(PTOGV(Dest), (GenericValue*)(Result+i),
92                             Type::IntTy);
93    }
94    Result[InputArgv.size()] = 0;  // null terminate it
95    return Result;
96  }
97}
98
99/// callAsMain - Call the function named FnName from M as if its
100/// signature were int main (int argc, char **argv, const char
101/// **envp), using the contents of Args to determine argc & argv, and
102/// the contents of EnvVars to determine envp.  Returns the result
103/// from calling FnName, or -1 and prints an error msg. if the named
104/// function cannot be found.
105///
106int callAsMain(ExecutionEngine *EE, ModuleProvider *MP,
107               const std::string &FnName,
108               const std::vector<std::string> &Args,
109               const std::vector<std::string> &EnvVars) {
110  Function *Fn = MP->getModule()->getNamedFunction(FnName);
111  if (!Fn) {
112    std::cerr << "Function '" << FnName << "' not found in module.\n";
113    return -1;
114  }
115  std::vector<GenericValue> GVArgs;
116  GenericValue GVArgc;
117  GVArgc.IntVal = Args.size();
118  GVArgs.push_back(GVArgc); // Arg #0 = argc.
119  GVArgs.push_back(PTOGV(CreateArgv(EE, Args))); // Arg #1 = argv.
120  assert(((char **)GVTOP(GVArgs[1]))[0] && "argv[0] was null after CreateArgv");
121  GVArgs.push_back(PTOGV(CreateArgv(EE, EnvVars))); // Arg #2 = envp.
122  return EE->run(Fn, GVArgs).IntVal;
123}
124
125//===----------------------------------------------------------------------===//
126// main Driver function
127//
128int main(int argc, char **argv, char * const *envp) {
129  cl::ParseCommandLineOptions(argc, argv,
130                              " llvm interpreter & dynamic compiler\n");
131
132  // Load the bytecode...
133  std::string ErrorMsg;
134  ModuleProvider *MP = 0;
135  try {
136    MP = getBytecodeModuleProvider(InputFile);
137  } catch (std::string &err) {
138    std::cerr << "Error loading program '" << InputFile << "': " << err << "\n";
139    exit(1);
140  }
141
142  ExecutionEngine *EE =
143    ExecutionEngine::create(MP, ForceInterpreter);
144  assert(EE && "Couldn't create an ExecutionEngine, not even an interpreter?");
145
146  // If the user specifically requested an argv[0] to pass into the program, do
147  // it now.
148  if (!FakeArgv0.empty()) {
149    InputFile = FakeArgv0;
150  } else {
151    // Otherwise, if there is a .bc suffix on the executable strip it off, it
152    // might confuse the program.
153    if (InputFile.rfind(".bc") == InputFile.length() - 3)
154      InputFile.erase(InputFile.length() - 3);
155  }
156
157  // Add the module's name to the start of the vector of arguments to main().
158  InputArgv.insert(InputArgv.begin(), InputFile);
159
160  // Run the main function!
161  int ExitCode = callAsMain(EE, MP, MainFunction, InputArgv,
162                            makeStringVector(envp));
163
164  // Now that we are done executing the program, shut down the execution engine
165  delete EE;
166  return ExitCode;
167}
168