Interpreter.cpp revision 9f2f142d255bc96f109dd5c6524a485937b1f3a1 
1//===- Interpreter.cpp - Top-Level LLVM Interpreter Implementation --------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source 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"
21using namespace llvm;
22
23static struct RegisterInterp {
24  RegisterInterp() { Interpreter::Register(); }
25} InterpRegistrator;
26
27namespace llvm {
28  void LinkInInterpreter() {
29  }
30}
31
32/// create - Create a new interpreter object.  This can never fail.
33///
34ExecutionEngine *Interpreter::create(ModuleProvider *MP, std::string* ErrStr) {
35  // Tell this ModuleProvide to materialize and release the module
36  if (!MP->materializeModule(ErrStr))
37    // We got an error, just return 0
38    return 0;
39
40  return new Interpreter(MP);
41}
42
43//===----------------------------------------------------------------------===//
44// Interpreter ctor - Initialize stuff
45//
46Interpreter::Interpreter(ModuleProvider *M)
47  : ExecutionEngine(M), TD(M->getModule()) {
48
49  memset(&ExitValue.Untyped, 0, sizeof(ExitValue.Untyped));
50  setTargetData(&TD);
51  // Initialize the "backend"
52  initializeExecutionEngine();
53  initializeExternalFunctions();
54  emitGlobals();
55
56  IL = new IntrinsicLowering(TD);
57}
58
59Interpreter::~Interpreter() {
60  delete IL;
61}
62
63void Interpreter::runAtExitHandlers () {
64  while (!AtExitHandlers.empty()) {
65    callFunction(AtExitHandlers.back(), std::vector<GenericValue>());
66    AtExitHandlers.pop_back();
67    run();
68  }
69}
70
71/// run - Start execution with the specified function and arguments.
72///
73GenericValue
74Interpreter::runFunction(Function *F,
75                         const std::vector<GenericValue> &ArgValues) {
76  assert (F && "Function *F was null at entry to run()");
77
78  // Try extra hard not to pass extra args to a function that isn't
79  // expecting them.  C programmers frequently bend the rules and
80  // declare main() with fewer parameters than it actually gets
81  // passed, and the interpreter barfs if you pass a function more
82  // parameters than it is declared to take. This does not attempt to
83  // take into account gratuitous differences in declared types,
84  // though.
85  std::vector<GenericValue> ActualArgs;
86  const unsigned ArgCount = F->getFunctionType()->getNumParams();
87  for (unsigned i = 0; i < ArgCount; ++i)
88    ActualArgs.push_back(ArgValues[i]);
89
90  // Set up the function call.
91  callFunction(F, ActualArgs);
92
93  // Start executing the function.
94  run();
95
96  return ExitValue;
97}
98
99