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 (M->MaterializeAllPermanently(ErrStr))
38    // We got an error, just return 0
39    return 0;
40
41  return new Interpreter(M);
42}
43
44//===----------------------------------------------------------------------===//
45// Interpreter ctor - Initialize stuff
46//
47Interpreter::Interpreter(Module *M)
48  : ExecutionEngine(M), TD(M) {
49
50  memset(&ExitValue.Untyped, 0, sizeof(ExitValue.Untyped));
51  setDataLayout(&TD);
52  // Initialize the "backend"
53  initializeExecutionEngine();
54  initializeExternalFunctions();
55  emitGlobals();
56
57  IL = new IntrinsicLowering(TD);
58}
59
60Interpreter::~Interpreter() {
61  delete IL;
62}
63
64void Interpreter::runAtExitHandlers () {
65  while (!AtExitHandlers.empty()) {
66    callFunction(AtExitHandlers.back(), std::vector<GenericValue>());
67    AtExitHandlers.pop_back();
68    run();
69  }
70}
71
72/// run - Start execution with the specified function and arguments.
73///
74GenericValue
75Interpreter::runFunction(Function *F,
76                         const std::vector<GenericValue> &ArgValues) {
77  assert (F && "Function *F was null at entry to run()");
78
79  // Try extra hard not to pass extra args to a function that isn't
80  // expecting them.  C programmers frequently bend the rules and
81  // declare main() with fewer parameters than it actually gets
82  // passed, and the interpreter barfs if you pass a function more
83  // parameters than it is declared to take. This does not attempt to
84  // take into account gratuitous differences in declared types,
85  // though.
86  std::vector<GenericValue> ActualArgs;
87  const unsigned ArgCount = F->getFunctionType()->getNumParams();
88  for (unsigned i = 0; i < ArgCount; ++i)
89    ActualArgs.push_back(ArgValues[i]);
90
91  // Set up the function call.
92  callFunction(F, ActualArgs);
93
94  // Start executing the function.
95  run();
96
97  return ExitValue;
98}
99