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 extern "C" void LLVMLinkInInterpreter() { }
  33
  34 /// create - Create a new interpreter object.  This can never fail.
  35 ///
  36 ExecutionEngine *Interpreter::create(ModuleProvider *MP, std::string* ErrStr) {
  37   // Tell this ModuleProvide to materialize and release the module
  38   if (!MP->materializeModule(ErrStr))
  39     // We got an error, just return 0
  40     return 0;
  41
  42   return new Interpreter(MP);
  43 }
  44
  45 //===----------------------------------------------------------------------===//
  46 // Interpreter ctor - Initialize stuff
  47 //
  48 Interpreter::Interpreter(ModuleProvider *M)
  49   : ExecutionEngine(M), TD(M->getModule()) {
  50
  51   memset(&ExitValue.Untyped, 0, sizeof(ExitValue.Untyped));
  52   setTargetData(&TD);
  53   // Initialize the "backend"
  54   initializeExecutionEngine();
  55   initializeExternalFunctions();
  56   emitGlobals();
  57
  58   IL = new IntrinsicLowering(TD);
  59 }
  60
  61 Interpreter::~Interpreter() {
  62   delete IL;
  63 }
  64
  65 void Interpreter::runAtExitHandlers () {
  66   while (!AtExitHandlers.empty()) {
  67     callFunction(AtExitHandlers.back(), std::vector<GenericValue>());
  68     AtExitHandlers.pop_back();
  69     run();
  70   }
  71 }
  72
  73 /// run - Start execution with the specified function and arguments.
  74 ///
  75 GenericValue
  76 Interpreter::runFunction(Function *F,
  77                          const std::vector<GenericValue> &ArgValues) {
  78   assert (F && "Function *F was null at entry to run()");
  79
  80   // Try extra hard not to pass extra args to a function that isn't
  81   // expecting them.  C programmers frequently bend the rules and
  82   // declare main() with fewer parameters than it actually gets
  83   // passed, and the interpreter barfs if you pass a function more
  84   // parameters than it is declared to take. This does not attempt to
  85   // take into account gratuitous differences in declared types,
  86   // though.
  87   std::vector<GenericValue> ActualArgs;
  88   const unsigned ArgCount = F->getFunctionType()->getNumParams();
  89   for (unsigned i = 0; i < ArgCount; ++i)
  90     ActualArgs.push_back(ArgValues[i]);
  91
  92   // Set up the function call.
  93   callFunction(F, ActualArgs);
  94
  95   // Start executing the function.
  96   run();
  97
  98   return ExitValue;
  99 }