src/llvm/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/IR/DerivedTypes.h"
  19 #include "llvm/IR/Module.h"
  20 #include <cstring>
  21 using namespace llvm;
  22
  23 namespace {
  24
  25 static struct RegisterInterp {
  26   RegisterInterp() { Interpreter::Register(); }
  27 } InterpRegistrator;
  28
  29 }
  30
  31 extern "C" void LLVMLinkInInterpreter() { }
  32
  33 /// Create a new interpreter object.
  34 ///
  35 ExecutionEngine *Interpreter::create(std::unique_ptr<Module> M,
  36                                      std::string *ErrStr) {
  37   // Tell this Module to materialize everything and release the GVMaterializer.
  38   if (std::error_code EC = M->materializeAllPermanently()) {
  39     if (ErrStr)
  40       *ErrStr = EC.message();
  41     // We got an error, just return 0
  42     return nullptr;
  43   }
  44
  45   return new Interpreter(std::move(M));
  46 }
  47
  48 //===----------------------------------------------------------------------===//
  49 // Interpreter ctor - Initialize stuff
  50 //
  51 Interpreter::Interpreter(std::unique_ptr<Module> M)
  52   : ExecutionEngine(std::move(M)), TD(Modules.back().get()) {
  53
  54   memset(&ExitValue.Untyped, 0, sizeof(ExitValue.Untyped));
  55   setDataLayout(&TD);
  56   // Initialize the "backend"
  57   initializeExecutionEngine();
  58   initializeExternalFunctions();
  59   emitGlobals();
  60
  61   IL = new IntrinsicLowering(TD);
  62 }
  63
  64 Interpreter::~Interpreter() {
  65   delete IL;
  66 }
  67
  68 void Interpreter::runAtExitHandlers () {
  69   while (!AtExitHandlers.empty()) {
  70     callFunction(AtExitHandlers.back(), std::vector<GenericValue>());
  71     AtExitHandlers.pop_back();
  72     run();
  73   }
  74 }
  75
  76 /// run - Start execution with the specified function and arguments.
  77 ///
  78 GenericValue
  79 Interpreter::runFunction(Function *F,
  80                          const std::vector<GenericValue> &ArgValues) {
  81   assert (F && "Function *F was null at entry to run()");
  82
  83   // Try extra hard not to pass extra args to a function that isn't
  84   // expecting them.  C programmers frequently bend the rules and
  85   // declare main() with fewer parameters than it actually gets
  86   // passed, and the interpreter barfs if you pass a function more
  87   // parameters than it is declared to take. This does not attempt to
  88   // take into account gratuitous differences in declared types,
  89   // though.
  90   std::vector<GenericValue> ActualArgs;
  91   const unsigned ArgCount = F->getFunctionType()->getNumParams();
  92   for (unsigned i = 0; i < ArgCount; ++i)
  93     ActualArgs.push_back(ArgValues[i]);
  94
  95   // Set up the function call.
  96   callFunction(F, ActualArgs);
  97
  98   // Start executing the function.
  99   run();
 100
 101   return ExitValue;
 102 }