Interpreter.cpp revision 36b56886974eae4f9c5ebc96befd3e7bfe5de338 
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>
21using namespace llvm;
22
23namespace {
24
25static struct RegisterInterp {
26  RegisterInterp() { Interpreter::Register(); }
27} InterpRegistrator;
28
29}
30
31extern "C" void LLVMLinkInInterpreter() { }
32
33/// create - Create a new interpreter object.  This can never fail.
34///
35ExecutionEngine *Interpreter::create(Module *M, std::string* ErrStr) {
36  // Tell this Module to materialize everything and release the GVMaterializer.
37  if (error_code EC = M->materializeAllPermanently()) {
38    if (ErrStr)
39      *ErrStr = EC.message();
40    // We got an error, just return 0
41    return 0;
42  }
43
44  return new Interpreter(M);
45}
46
47//===----------------------------------------------------------------------===//
48// Interpreter ctor - Initialize stuff
49//
50Interpreter::Interpreter(Module *M)
51  : ExecutionEngine(M), TD(M) {
52
53  memset(&ExitValue.Untyped, 0, sizeof(ExitValue.Untyped));
54  setDataLayout(&TD);
55  // Initialize the "backend"
56  initializeExecutionEngine();
57  initializeExternalFunctions();
58  emitGlobals();
59
60  IL = new IntrinsicLowering(TD);
61}
62
63Interpreter::~Interpreter() {
64  delete IL;
65}
66
67void Interpreter::runAtExitHandlers () {
68  while (!AtExitHandlers.empty()) {
69    callFunction(AtExitHandlers.back(), std::vector<GenericValue>());
70    AtExitHandlers.pop_back();
71    run();
72  }
73}
74
75/// run - Start execution with the specified function and arguments.
76///
77GenericValue
78Interpreter::runFunction(Function *F,
79                         const std::vector<GenericValue> &ArgValues) {
80  assert (F && "Function *F was null at entry to run()");
81
82  // Try extra hard not to pass extra args to a function that isn't
83  // expecting them.  C programmers frequently bend the rules and
84  // declare main() with fewer parameters than it actually gets
85  // passed, and the interpreter barfs if you pass a function more
86  // parameters than it is declared to take. This does not attempt to
87  // take into account gratuitous differences in declared types,
88  // though.
89  std::vector<GenericValue> ActualArgs;
90  const unsigned ArgCount = F->getFunctionType()->getNumParams();
91  for (unsigned i = 0; i < ArgCount; ++i)
92    ActualArgs.push_back(ArgValues[i]);
93
94  // Set up the function call.
95  callFunction(F, ActualArgs);
96
97  // Start executing the function.
98  run();
99
100  return ExitValue;
101}
102