llvm-rtdyld.cpp revision 30b9e322e159df8eaabb5b194cec6e11ba99c261 
1//===-- llvm-rtdyld.cpp - MCJIT Testing Tool ------------------------------===//
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 is a testing tool for use with the MC-JIT LLVM components.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/ADT/StringMap.h"
15#include "llvm/ADT/OwningPtr.h"
16#include "llvm/ExecutionEngine/RuntimeDyld.h"
17#include "llvm/Object/MachOObject.h"
18#include "llvm/Support/CommandLine.h"
19#include "llvm/Support/ManagedStatic.h"
20#include "llvm/Support/Memory.h"
21#include "llvm/Support/MemoryBuffer.h"
22#include "llvm/Support/raw_ostream.h"
23#include "llvm/Support/system_error.h"
24using namespace llvm;
25using namespace llvm::object;
26
27static cl::list<std::string>
28InputFileList(cl::Positional, cl::ZeroOrMore,
29              cl::desc("<input file>"));
30
31enum ActionType {
32  AC_Execute
33};
34
35static cl::opt<ActionType>
36Action(cl::desc("Action to perform:"),
37       cl::init(AC_Execute),
38       cl::values(clEnumValN(AC_Execute, "execute",
39                             "Load, link, and execute the inputs."),
40                  clEnumValEnd));
41
42static cl::opt<std::string>
43EntryPoint("entry",
44           cl::desc("Function to call as entry point."),
45           cl::init("_main"));
46
47/* *** */
48
49// A trivial memory manager that doesn't do anything fancy, just uses the
50// support library allocation routines directly.
51class TrivialMemoryManager : public RTDyldMemoryManager {
52public:
53  SmallVector<sys::MemoryBlock, 16> FunctionMemory;
54  SmallVector<sys::MemoryBlock, 16> DataMemory;
55
56  uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
57                               unsigned SectionID);
58  uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
59                               unsigned SectionID);
60
61  uint8_t *startFunctionBody(const char *Name, uintptr_t &Size);
62  void endFunctionBody(const char *Name, uint8_t *FunctionStart,
63                       uint8_t *FunctionEnd);
64
65  virtual void *getPointerToNamedFunction(const std::string &Name,
66                                          bool AbortOnFailure = true) {
67    return 0;
68  }
69
70};
71
72uint8_t *TrivialMemoryManager::allocateCodeSection(uintptr_t Size,
73                                                   unsigned Alignment,
74                                                   unsigned SectionID) {
75  return (uint8_t*)sys::Memory::AllocateRWX(Size, 0, 0).base();
76}
77
78uint8_t *TrivialMemoryManager::allocateDataSection(uintptr_t Size,
79                                                   unsigned Alignment,
80                                                   unsigned SectionID) {
81  return (uint8_t*)sys::Memory::AllocateRWX(Size, 0, 0).base();
82}
83
84uint8_t *TrivialMemoryManager::startFunctionBody(const char *Name,
85                                                 uintptr_t &Size) {
86  return (uint8_t*)sys::Memory::AllocateRWX(Size, 0, 0).base();
87}
88
89void TrivialMemoryManager::endFunctionBody(const char *Name,
90                                           uint8_t *FunctionStart,
91                                           uint8_t *FunctionEnd) {
92  uintptr_t Size = FunctionEnd - FunctionStart + 1;
93  FunctionMemory.push_back(sys::MemoryBlock(FunctionStart, Size));
94}
95
96static const char *ProgramName;
97
98static void Message(const char *Type, const Twine &Msg) {
99  errs() << ProgramName << ": " << Type << ": " << Msg << "\n";
100}
101
102static int Error(const Twine &Msg) {
103  Message("error", Msg);
104  return 1;
105}
106
107/* *** */
108
109static int executeInput() {
110  // Instantiate a dynamic linker.
111  TrivialMemoryManager *MemMgr = new TrivialMemoryManager;
112  RuntimeDyld Dyld(MemMgr);
113
114  // If we don't have any input files, read from stdin.
115  if (!InputFileList.size())
116    InputFileList.push_back("-");
117  for(unsigned i = 0, e = InputFileList.size(); i != e; ++i) {
118    // Load the input memory buffer.
119    OwningPtr<MemoryBuffer> InputBuffer;
120    if (error_code ec = MemoryBuffer::getFileOrSTDIN(InputFileList[i],
121                                                     InputBuffer))
122      return Error("unable to read input: '" + ec.message() + "'");
123
124    // Load the object file into it.
125    if (Dyld.loadObject(InputBuffer.take())) {
126      return Error(Dyld.getErrorString());
127    }
128  }
129
130  // Resolve all the relocations we can.
131  Dyld.resolveRelocations();
132
133  // FIXME: Error out if there are unresolved relocations.
134
135  // Get the address of the entry point (_main by default).
136  void *MainAddress = Dyld.getSymbolAddress(EntryPoint);
137  if (MainAddress == 0)
138    return Error("no definition for '" + EntryPoint + "'");
139
140  // Invalidate the instruction cache for each loaded function.
141  for (unsigned i = 0, e = MemMgr->FunctionMemory.size(); i != e; ++i) {
142    sys::MemoryBlock &Data = MemMgr->FunctionMemory[i];
143    // Make sure the memory is executable.
144    std::string ErrorStr;
145    sys::Memory::InvalidateInstructionCache(Data.base(), Data.size());
146    if (!sys::Memory::setExecutable(Data, &ErrorStr))
147      return Error("unable to mark function executable: '" + ErrorStr + "'");
148  }
149
150  // Dispatch to _main().
151  errs() << "loaded '" << EntryPoint << "' at: " << (void*)MainAddress << "\n";
152
153  int (*Main)(int, const char**) =
154    (int(*)(int,const char**)) uintptr_t(MainAddress);
155  const char **Argv = new const char*[2];
156  // Use the name of the first input object module as argv[0] for the target.
157  Argv[0] = InputFileList[0].c_str();
158  Argv[1] = 0;
159  return Main(1, Argv);
160}
161
162int main(int argc, char **argv) {
163  ProgramName = argv[0];
164  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
165
166  cl::ParseCommandLineOptions(argc, argv, "llvm MC-JIT tool\n");
167
168  switch (Action) {
169  case AC_Execute:
170    return executeInput();
171  }
172}
173