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__anon8bd5f8450111::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 (Error Err = M->materializeAll()) {
39 std::string Msg;
40 handleAllErrors(std::move(Err), [&](ErrorInfoBase &EIB) {
41 Msg = EIB.message();
42 });
43 if (ErrStr)
44 *ErrStr = Msg;
45 // We got an error, just return 0
46 return nullptr;
47 }
48
49 return new Interpreter(std::move(M));
50 }
51
52 //===----------------------------------------------------------------------===//
53 // Interpreter ctor - Initialize stuff
54 //
Interpreter(std::unique_ptr<Module> M)55 Interpreter::Interpreter(std::unique_ptr<Module> M)
56 : ExecutionEngine(std::move(M)) {
57
58 memset(&ExitValue.Untyped, 0, sizeof(ExitValue.Untyped));
59 // Initialize the "backend"
60 initializeExecutionEngine();
61 initializeExternalFunctions();
62 emitGlobals();
63
64 IL = new IntrinsicLowering(getDataLayout());
65 }
66
~Interpreter()67 Interpreter::~Interpreter() {
68 delete IL;
69 }
70
runAtExitHandlers()71 void Interpreter::runAtExitHandlers () {
72 while (!AtExitHandlers.empty()) {
73 callFunction(AtExitHandlers.back(), None);
74 AtExitHandlers.pop_back();
75 run();
76 }
77 }
78
79 /// run - Start execution with the specified function and arguments.
80 ///
runFunction(Function * F,ArrayRef<GenericValue> ArgValues)81 GenericValue Interpreter::runFunction(Function *F,
82 ArrayRef<GenericValue> ArgValues) {
83 assert (F && "Function *F was null at entry to run()");
84
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,
91 // though.
92 const size_t ArgCount = F->getFunctionType()->getNumParams();
93 ArrayRef<GenericValue> ActualArgs =
94 ArgValues.slice(0, std::min(ArgValues.size(), ArgCount));
95
96 // Set up the function call.
97 callFunction(F, ActualArgs);
98
99 // Start executing the function.
100 run();
101
102 return ExitValue;
103 }
104