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>
21 using namespace llvm;
22
23 namespace {
24
25 static struct RegisterInterp {
RegisterInterp__anon7784a2790111::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 (std::error_code EC = M->materializeAllPermanently()) {
38 if (ErrStr)
39 *ErrStr = EC.message();
40 // We got an error, just return 0
41 return nullptr;
42 }
43
44 return new Interpreter(M);
45 }
46
47 //===----------------------------------------------------------------------===//
48 // Interpreter ctor - Initialize stuff
49 //
Interpreter(Module * M)50 Interpreter::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
~Interpreter()63 Interpreter::~Interpreter() {
64 delete IL;
65 }
66
runAtExitHandlers()67 void 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 ///
77 GenericValue
runFunction(Function * F,const std::vector<GenericValue> & ArgValues)78 Interpreter::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