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__anon0d031f2b0111::RegisterInterp26 RegisterInterp() { Interpreter::Register(); }
27 } InterpRegistrator;
28
29 }
30
LLVMLinkInInterpreter()31 extern "C" void LLVMLinkInInterpreter() { }
32
33 /// Create a new interpreter object.
34 ///
create(std::unique_ptr<Module> M,std::string * ErrStr)35 ExecutionEngine *Interpreter::create(std::unique_ptr<Module> M,
36 std::string *ErrStr) {
37 // Tell this Module to materialize everything and release the GVMaterializer.
38 if (std::error_code EC = M->materializeAll()) {
39 if (ErrStr)
40 *ErrStr = EC.message();
41 // We got an error, just return 0
42 return nullptr;
43 }
44
45 return new Interpreter(std::move(M));
46 }
47
48 //===----------------------------------------------------------------------===//
49 // Interpreter ctor - Initialize stuff
50 //
Interpreter(std::unique_ptr<Module> M)51 Interpreter::Interpreter(std::unique_ptr<Module> M)
52 : ExecutionEngine(std::move(M)) {
53
54 memset(&ExitValue.Untyped, 0, sizeof(ExitValue.Untyped));
55 // Initialize the "backend"
56 initializeExecutionEngine();
57 initializeExternalFunctions();
58 emitGlobals();
59
60 IL = new IntrinsicLowering(getDataLayout());
61 }
62
~Interpreter()63 Interpreter::~Interpreter() {
64 delete IL;
65 }
66
runAtExitHandlers()67 void Interpreter::runAtExitHandlers () {
68 while (!AtExitHandlers.empty()) {
69 callFunction(AtExitHandlers.back(), None);
70 AtExitHandlers.pop_back();
71 run();
72 }
73 }
74
75 /// run - Start execution with the specified function and arguments.
76 ///
runFunction(Function * F,ArrayRef<GenericValue> ArgValues)77 GenericValue Interpreter::runFunction(Function *F,
78 ArrayRef<GenericValue> ArgValues) {
79 assert (F && "Function *F was null at entry to run()");
80
81 // Try extra hard not to pass extra args to a function that isn't
82 // expecting them. C programmers frequently bend the rules and
83 // declare main() with fewer parameters than it actually gets
84 // passed, and the interpreter barfs if you pass a function more
85 // parameters than it is declared to take. This does not attempt to
86 // take into account gratuitous differences in declared types,
87 // though.
88 const size_t ArgCount = F->getFunctionType()->getNumParams();
89 ArrayRef<GenericValue> ActualArgs =
90 ArgValues.slice(0, std::min(ArgValues.size(), ArgCount));
91
92 // Set up the function call.
93 callFunction(F, ActualArgs);
94
95 // Start executing the function.
96 run();
97
98 return ExitValue;
99 }
100