lib/ExecutionEngine/Interpreter/Interpreter.cpp

   1 //===- Interpreter.cpp - Top-Level LLVM Interpreter Implementation --------===//
   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 file implements the top-level functionality for the LLVM interpreter.
  11 // This interpreter is designed to be a very simple, portable, inefficient
  12 // interpreter.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #include "Interpreter.h"
  17 #include "llvm/CodeGen/IntrinsicLowering.h"
  18 #include "llvm/DerivedTypes.h"
  19 #include "llvm/Module.h"
  20 #include "llvm/ModuleProvider.h"
  21 #include <cstring>
  22 using namespace llvm;
  23
  24 namespace {
  25
  26 static struct RegisterInterp {
  27   RegisterInterp() { Interpreter::Register(); }
  28 } InterpRegistrator;
  29
  30 }
  31
  32 namespace llvm {
  33   void LinkInInterpreter() {
  34   }
  35 }
  36
  37 /// create - Create a new interpreter object.  This can never fail.
  38 ///
  39 ExecutionEngine *Interpreter::create(ModuleProvider *MP, std::string* ErrStr,
  40                                      CodeGenOpt::Level OptLevel /*unused*/) {
  41   // Tell this ModuleProvide to materialize and release the module
  42   if (!MP->materializeModule(ErrStr))
  43     // We got an error, just return 0
  44     return 0;
  45
  46   return new Interpreter(MP);
  47 }
  48
  49 //===----------------------------------------------------------------------===//
  50 // Interpreter ctor - Initialize stuff
  51 //
  52 Interpreter::Interpreter(ModuleProvider *M)
  53   : ExecutionEngine(M), TD(M->getModule()) {
  54
  55   memset(&ExitValue.Untyped, 0, sizeof(ExitValue.Untyped));
  56   setTargetData(&TD);
  57   // Initialize the "backend"
  58   initializeExecutionEngine();
  59   initializeExternalFunctions();
  60   emitGlobals();
  61
  62   IL = new IntrinsicLowering(TD);
  63 }
  64
  65 Interpreter::~Interpreter() {
  66   delete IL;
  67 }
  68
  69 void Interpreter::runAtExitHandlers () {
  70   while (!AtExitHandlers.empty()) {
  71     callFunction(AtExitHandlers.back(), std::vector<GenericValue>());
  72     AtExitHandlers.pop_back();
  73     run();
  74   }
  75 }
  76
  77 /// run - Start execution with the specified function and arguments.
  78 ///
  79 GenericValue
  80 Interpreter::runFunction(Function *F,
  81                          const std::vector<GenericValue> &ArgValues) {
  82   assert (F && "Function *F was null at entry to run()");
  83
  84   // Try extra hard not to pass extra args to a function that isn't
  85   // expecting them.  C programmers frequently bend the rules and
  86   // declare main() with fewer parameters than it actually gets
  87   // passed, and the interpreter barfs if you pass a function more
  88   // parameters than it is declared to take. This does not attempt to
  89   // take into account gratuitous differences in declared types,
  90   // though.
  91   std::vector<GenericValue> ActualArgs;
  92   const unsigned ArgCount = F->getFunctionType()->getNumParams();
  93   for (unsigned i = 0; i < ArgCount; ++i)
  94     ActualArgs.push_back(ArgValues[i]);
  95
  96   // Set up the function call.
  97   callFunction(F, ActualArgs);
  98
  99   // Start executing the function.
 100   run();
 101
 102   return ExitValue;
 103 }
 104