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/DerivedTypes.h"
19 #include "llvm/Module.h"
20 #include <cstring>
21 using namespace llvm;
22
23 namespace {
24
25 static struct RegisterInterp {
RegisterInterp__anone7fd2cee0111::RegisterInterp26 RegisterInterp() { Interpreter::Register(); }
27 } InterpRegistrator;
28
29 }
30
LLVMLinkInInterpreter()31 extern "C" void LLVMLinkInInterpreter() { }
32
33 /// create - Create a new interpreter object. This can never fail.
34 ///
create(Module * M,std::string * ErrStr)35 ExecutionEngine *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 //
Interpreter(Module * M)47 Interpreter::Interpreter(Module *M)
48 : ExecutionEngine(M), TD(M) {
49
50 memset(&ExitValue.Untyped, 0, sizeof(ExitValue.Untyped));
51 setTargetData(&TD);
52 // Initialize the "backend"
53 initializeExecutionEngine();
54 initializeExternalFunctions();
55 emitGlobals();
56
57 IL = new IntrinsicLowering(TD);
58 }
59
~Interpreter()60 Interpreter::~Interpreter() {
61 delete IL;
62 }
63
runAtExitHandlers()64 void 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 ///
74 GenericValue
runFunction(Function * F,const std::vector<GenericValue> & ArgValues)75 Interpreter::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