Interpreter.cpp revision 198090 
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>
22using namespace llvm;
23
24namespace {
25
26static struct RegisterInterp {
27  RegisterInterp() { Interpreter::Register(); }
28} InterpRegistrator;
29
30}
31
32extern "C" void LLVMLinkInInterpreter() { }
33
34/// create - Create a new interpreter object.  This can never fail.
35///
36ExecutionEngine *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//
48Interpreter::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
61Interpreter::~Interpreter() {
62  delete IL;
63}
64
65void 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///
75GenericValue
76Interpreter::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}
100