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      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 }
    152