1 //===- Interpreter.cpp - Top-Level LLVM Interpreter Implementation --------===//
3 // The LLVM Compiler Infrastructure
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.
8 //===----------------------------------------------------------------------===//
10 // This file implements the top-level functionality for the LLVM interpreter.
11 // This interpreter is designed to be a very simple, portable, inefficient
14 //===----------------------------------------------------------------------===//
16 #include "Interpreter.h"
17 #include "llvm/CodeGen/IntrinsicLowering.h"
18 #include "llvm/DerivedTypes.h"
19 #include "llvm/Module.h"
22 /// create - Create a new interpreter object. This can never fail.
24 ExecutionEngine *Interpreter::create(Module *M, IntrinsicLowering *IL) {
25 bool isLittleEndian = false;
26 switch (M->getEndianness()) {
27 case Module::LittleEndian: isLittleEndian = true; break;
28 case Module::BigEndian: isLittleEndian = false; break;
29 case Module::AnyPointerSize:
31 *(char*)&Test = 1; // Return true if the host is little endian
32 isLittleEndian = (Test == 1);
36 bool isLongPointer = false;
37 switch (M->getPointerSize()) {
38 case Module::Pointer32: isLongPointer = false; break;
39 case Module::Pointer64: isLongPointer = true; break;
40 case Module::AnyPointerSize:
41 isLongPointer = (sizeof(void*) == 8); // Follow host
45 return new Interpreter(M, isLittleEndian, isLongPointer, IL);
48 //===----------------------------------------------------------------------===//
49 // Interpreter ctor - Initialize stuff
51 Interpreter::Interpreter(Module *M, bool isLittleEndian, bool isLongPointer,
52 IntrinsicLowering *il)
53 : ExecutionEngine(M), ExitCode(0),
54 TD("lli", isLittleEndian, isLongPointer ? 8 : 4, isLongPointer ? 8 : 4,
55 isLongPointer ? 8 : 4), IL(il) {
58 // Initialize the "backend"
59 initializeExecutionEngine();
60 initializeExternalFunctions();
63 if (IL == 0) IL = new DefaultIntrinsicLowering();
66 Interpreter::~Interpreter() {
70 void Interpreter::runAtExitHandlers () {
71 while (!AtExitHandlers.empty()) {
72 callFunction(AtExitHandlers.back(), std::vector<GenericValue>());
73 AtExitHandlers.pop_back();
78 /// run - Start execution with the specified function and arguments.
81 Interpreter::runFunction(Function *F,
82 const std::vector<GenericValue> &ArgValues) {
83 assert (F && "Function *F was null at entry to run()");
85 // Try extra hard not to pass extra args to a function that isn't
86 // expecting them. C programmers frequently bend the rules and
87 // declare main() with fewer parameters than it actually gets
88 // passed, and the interpreter barfs if you pass a function more
89 // parameters than it is declared to take. This does not attempt to
90 // take into account gratuitous differences in declared types,
92 std::vector<GenericValue> ActualArgs;
93 const unsigned ArgCount = F->getFunctionType()->getNumParams();
94 for (unsigned i = 0; i < ArgCount; ++i)
95 ActualArgs.push_back(ArgValues[i]);
97 // Set up the function call.
98 callFunction(F, ActualArgs);
100 // Start executing the function.
104 rv.IntVal = ExitCode;