tools/llvm-rtdyld/llvm-rtdyld.cpp

   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"
  24 using namespace llvm;
  25 using namespace llvm::object;
  26
  27 static cl::list<std::string>
  28 InputFileList(cl::Positional, cl::ZeroOrMore,
  29               cl::desc("<input file>"));
  30
  31 enum ActionType {
  32   AC_Execute
  33 };
  34
  35 static cl::opt<ActionType>
  36 Action(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
  42 static cl::opt<std::string>
  43 EntryPoint("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.
  51 class TrivialMemoryManager : public RTDyldMemoryManager {
  52 public:
  53   SmallVector<sys::MemoryBlock, 16> FunctionMemory;
  54
  55   uint8_t *startFunctionBody(const char *Name, uintptr_t &Size);
  56   void endFunctionBody(const char *Name, uint8_t *FunctionStart,
  57                        uint8_t *FunctionEnd);
  58 };
  59
  60 uint8_t *TrivialMemoryManager::startFunctionBody(const char *Name,
  61                                                  uintptr_t &Size) {
  62   return (uint8_t*)sys::Memory::AllocateRWX(Size, 0, 0).base();
  63 }
  64
  65 void TrivialMemoryManager::endFunctionBody(const char *Name,
  66                                            uint8_t *FunctionStart,
  67                                            uint8_t *FunctionEnd) {
  68   uintptr_t Size = FunctionEnd - FunctionStart + 1;
  69   FunctionMemory.push_back(sys::MemoryBlock(FunctionStart, Size));
  70 }
  71
  72 static const char *ProgramName;
  73
  74 static void Message(const char *Type, const Twine &Msg) {
  75   errs() << ProgramName << ": " << Type << ": " << Msg << "\n";
  76 }
  77
  78 static int Error(const Twine &Msg) {
  79   Message("error", Msg);
  80   return 1;
  81 }
  82
  83 /* *** */
  84
  85 static int executeInput() {
  86   // Instantiate a dynamic linker.
  87   TrivialMemoryManager *MemMgr = new TrivialMemoryManager;
  88   RuntimeDyld Dyld(MemMgr);
  89
  90   // If we don't have any input files, read from stdin.
  91   if (!InputFileList.size())
  92     InputFileList.push_back("-");
  93   for(unsigned i = 0, e = InputFileList.size(); i != e; ++i) {
  94     // Load the input memory buffer.
  95     OwningPtr<MemoryBuffer> InputBuffer;
  96     if (error_code ec = MemoryBuffer::getFileOrSTDIN(InputFileList[i],
  97                                                      InputBuffer))
  98       return Error("unable to read input: '" + ec.message() + "'");
  99
 100     // Load the object file into it.
 101     if (Dyld.loadObject(InputBuffer.take())) {
 102       return Error(Dyld.getErrorString());
 103     }
 104   }
 105
 106   // Resolve all the relocations we can.
 107   Dyld.resolveRelocations();
 108
 109   // FIXME: Error out if there are unresolved relocations.
 110
 111   // Get the address of the entry point (_main by default).
 112   void *MainAddress = Dyld.getSymbolAddress(EntryPoint);
 113   if (MainAddress == 0)
 114     return Error("no definition for '" + EntryPoint + "'");
 115
 116   // Invalidate the instruction cache for each loaded function.
 117   for (unsigned i = 0, e = MemMgr->FunctionMemory.size(); i != e; ++i) {
 118     sys::MemoryBlock &Data = MemMgr->FunctionMemory[i];
 119     // Make sure the memory is executable.
 120     std::string ErrorStr;
 121     sys::Memory::InvalidateInstructionCache(Data.base(), Data.size());
 122     if (!sys::Memory::setExecutable(Data, &ErrorStr))
 123       return Error("unable to mark function executable: '" + ErrorStr + "'");
 124   }
 125
 126   // Dispatch to _main().
 127   errs() << "loaded '" << EntryPoint << "' at: " << (void*)MainAddress << "\n";
 128
 129   int (*Main)(int, const char**) =
 130     (int(*)(int,const char**)) uintptr_t(MainAddress);
 131   const char **Argv = new const char*[2];
 132   // Use the name of the first input object module as argv[0] for the target.
 133   Argv[0] = InputFileList[0].c_str();
 134   Argv[1] = 0;
 135   return Main(1, Argv);
 136 }
 137
 138 int main(int argc, char **argv) {
 139   ProgramName = argv[0];
 140   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
 141
 142   cl::ParseCommandLineOptions(argc, argv, "llvm MC-JIT tool\n");
 143
 144   switch (Action) {
 145   default:
 146   case AC_Execute:
 147     return executeInput();
 148   }
 149
 150   return 0;
 151 }