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/Module.h"
18 #include "llvm/DerivedTypes.h"
22 /// create - Create a new interpreter object. This can never fail.
24 ExecutionEngine *Interpreter::create(Module *M){
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);
48 //===----------------------------------------------------------------------===//
49 // Interpreter ctor - Initialize stuff
51 Interpreter::Interpreter(Module *M, bool isLittleEndian, bool isLongPointer)
52 : ExecutionEngine(M), ExitCode(0),
53 TD("lli", isLittleEndian, isLongPointer ? 8 : 4, isLongPointer ? 8 : 4,
54 isLongPointer ? 8 : 4) {
57 // Initialize the "backend"
58 initializeExecutionEngine();
59 initializeExternalFunctions();
63 void Interpreter::runAtExitHandlers () {
64 while (!AtExitHandlers.empty()) {
65 callFunction(AtExitHandlers.back(), std::vector<GenericValue>());
66 AtExitHandlers.pop_back();
71 /// run - Start execution with the specified function and arguments.
73 GenericValue Interpreter::run(Function *F,
74 const std::vector<GenericValue> &ArgValues) {
75 assert (F && "Function *F was null at entry to run()");
77 // Try extra hard not to pass extra args to a function that isn't
78 // expecting them. C programmers frequently bend the rules and
79 // declare main() with fewer parameters than it actually gets
80 // passed, and the interpreter barfs if you pass a function more
81 // parameters than it is declared to take. This does not attempt to
82 // take into account gratuitous differences in declared types,
84 std::vector<GenericValue> ActualArgs;
85 const unsigned ArgCount = F->getFunctionType()->getParamTypes().size();
86 for (unsigned i = 0; i < ArgCount; ++i)
87 ActualArgs.push_back (ArgValues[i]);
89 // Set up the function call.
90 callFunction(F, ActualArgs);
92 // Start executing the function.
95 // Run any atexit handlers now!
103 } // End llvm namespace