1//===-- Interpreter.h ------------------------------------------*- C++ -*--===//
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 header file defines the interpreter structure
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_LIB_EXECUTIONENGINE_INTERPRETER_INTERPRETER_H
15#define LLVM_LIB_EXECUTIONENGINE_INTERPRETER_INTERPRETER_H
16
17#include "llvm/ExecutionEngine/ExecutionEngine.h"
18#include "llvm/ExecutionEngine/GenericValue.h"
19#include "llvm/IR/CallSite.h"
20#include "llvm/IR/DataLayout.h"
21#include "llvm/IR/Function.h"
22#include "llvm/IR/InstVisitor.h"
23#include "llvm/Support/DataTypes.h"
24#include "llvm/Support/ErrorHandling.h"
25#include "llvm/Support/raw_ostream.h"
26namespace llvm {
27
28class IntrinsicLowering;
29template<typename T> class generic_gep_type_iterator;
30class ConstantExpr;
31typedef generic_gep_type_iterator<User::const_op_iterator> gep_type_iterator;
32
33
34// AllocaHolder - Object to track all of the blocks of memory allocated by
35// alloca.  When the function returns, this object is popped off the execution
36// stack, which causes the dtor to be run, which frees all the alloca'd memory.
37//
38class AllocaHolder {
39  std::vector<void *> Allocations;
40
41public:
42  AllocaHolder() {}
43
44  // Make this type move-only. Define explicit move special members for MSVC.
45  AllocaHolder(AllocaHolder &&RHS) : Allocations(std::move(RHS.Allocations)) {}
46  AllocaHolder &operator=(AllocaHolder &&RHS) {
47    Allocations = std::move(RHS.Allocations);
48    return *this;
49  }
50
51  ~AllocaHolder() {
52    for (void *Allocation : Allocations)
53      free(Allocation);
54  }
55
56  void add(void *Mem) { Allocations.push_back(Mem); }
57};
58
59typedef std::vector<GenericValue> ValuePlaneTy;
60
61// ExecutionContext struct - This struct represents one stack frame currently
62// executing.
63//
64struct ExecutionContext {
65  Function             *CurFunction;// The currently executing function
66  BasicBlock           *CurBB;      // The currently executing BB
67  BasicBlock::iterator  CurInst;    // The next instruction to execute
68  CallSite             Caller;     // Holds the call that called subframes.
69                                   // NULL if main func or debugger invoked fn
70  std::map<Value *, GenericValue> Values; // LLVM values used in this invocation
71  std::vector<GenericValue>  VarArgs; // Values passed through an ellipsis
72  AllocaHolder Allocas;            // Track memory allocated by alloca
73
74  ExecutionContext() : CurFunction(nullptr), CurBB(nullptr), CurInst(nullptr) {}
75
76  ExecutionContext(ExecutionContext &&O)
77      : CurFunction(O.CurFunction), CurBB(O.CurBB), CurInst(O.CurInst),
78        Caller(O.Caller), Values(std::move(O.Values)),
79        VarArgs(std::move(O.VarArgs)), Allocas(std::move(O.Allocas)) {}
80
81  ExecutionContext &operator=(ExecutionContext &&O) {
82    CurFunction = O.CurFunction;
83    CurBB = O.CurBB;
84    CurInst = O.CurInst;
85    Caller = O.Caller;
86    Values = std::move(O.Values);
87    VarArgs = std::move(O.VarArgs);
88    Allocas = std::move(O.Allocas);
89    return *this;
90  }
91};
92
93// Interpreter - This class represents the entirety of the interpreter.
94//
95class Interpreter : public ExecutionEngine, public InstVisitor<Interpreter> {
96  GenericValue ExitValue;          // The return value of the called function
97  IntrinsicLowering *IL;
98
99  // The runtime stack of executing code.  The top of the stack is the current
100  // function record.
101  std::vector<ExecutionContext> ECStack;
102
103  // AtExitHandlers - List of functions to call when the program exits,
104  // registered with the atexit() library function.
105  std::vector<Function*> AtExitHandlers;
106
107public:
108  explicit Interpreter(std::unique_ptr<Module> M);
109  ~Interpreter() override;
110
111  /// runAtExitHandlers - Run any functions registered by the program's calls to
112  /// atexit(3), which we intercept and store in AtExitHandlers.
113  ///
114  void runAtExitHandlers();
115
116  static void Register() {
117    InterpCtor = create;
118  }
119
120  /// Create an interpreter ExecutionEngine.
121  ///
122  static ExecutionEngine *create(std::unique_ptr<Module> M,
123                                 std::string *ErrorStr = nullptr);
124
125  /// run - Start execution with the specified function and arguments.
126  ///
127  GenericValue runFunction(Function *F,
128                           ArrayRef<GenericValue> ArgValues) override;
129
130  void *getPointerToNamedFunction(StringRef Name,
131                                  bool AbortOnFailure = true) override {
132    // FIXME: not implemented.
133    return nullptr;
134  }
135
136  // Methods used to execute code:
137  // Place a call on the stack
138  void callFunction(Function *F, ArrayRef<GenericValue> ArgVals);
139  void run();                // Execute instructions until nothing left to do
140
141  // Opcode Implementations
142  void visitReturnInst(ReturnInst &I);
143  void visitBranchInst(BranchInst &I);
144  void visitSwitchInst(SwitchInst &I);
145  void visitIndirectBrInst(IndirectBrInst &I);
146
147  void visitBinaryOperator(BinaryOperator &I);
148  void visitICmpInst(ICmpInst &I);
149  void visitFCmpInst(FCmpInst &I);
150  void visitAllocaInst(AllocaInst &I);
151  void visitLoadInst(LoadInst &I);
152  void visitStoreInst(StoreInst &I);
153  void visitGetElementPtrInst(GetElementPtrInst &I);
154  void visitPHINode(PHINode &PN) {
155    llvm_unreachable("PHI nodes already handled!");
156  }
157  void visitTruncInst(TruncInst &I);
158  void visitZExtInst(ZExtInst &I);
159  void visitSExtInst(SExtInst &I);
160  void visitFPTruncInst(FPTruncInst &I);
161  void visitFPExtInst(FPExtInst &I);
162  void visitUIToFPInst(UIToFPInst &I);
163  void visitSIToFPInst(SIToFPInst &I);
164  void visitFPToUIInst(FPToUIInst &I);
165  void visitFPToSIInst(FPToSIInst &I);
166  void visitPtrToIntInst(PtrToIntInst &I);
167  void visitIntToPtrInst(IntToPtrInst &I);
168  void visitBitCastInst(BitCastInst &I);
169  void visitSelectInst(SelectInst &I);
170
171
172  void visitCallSite(CallSite CS);
173  void visitCallInst(CallInst &I) { visitCallSite (CallSite (&I)); }
174  void visitInvokeInst(InvokeInst &I) { visitCallSite (CallSite (&I)); }
175  void visitUnreachableInst(UnreachableInst &I);
176
177  void visitShl(BinaryOperator &I);
178  void visitLShr(BinaryOperator &I);
179  void visitAShr(BinaryOperator &I);
180
181  void visitVAArgInst(VAArgInst &I);
182  void visitExtractElementInst(ExtractElementInst &I);
183  void visitInsertElementInst(InsertElementInst &I);
184  void visitShuffleVectorInst(ShuffleVectorInst &I);
185
186  void visitExtractValueInst(ExtractValueInst &I);
187  void visitInsertValueInst(InsertValueInst &I);
188
189  void visitInstruction(Instruction &I) {
190    errs() << I << "\n";
191    llvm_unreachable("Instruction not interpretable yet!");
192  }
193
194  GenericValue callExternalFunction(Function *F,
195                                    ArrayRef<GenericValue> ArgVals);
196  void exitCalled(GenericValue GV);
197
198  void addAtExitHandler(Function *F) {
199    AtExitHandlers.push_back(F);
200  }
201
202  GenericValue *getFirstVarArg () {
203    return &(ECStack.back ().VarArgs[0]);
204  }
205
206private:  // Helper functions
207  GenericValue executeGEPOperation(Value *Ptr, gep_type_iterator I,
208                                   gep_type_iterator E, ExecutionContext &SF);
209
210  // SwitchToNewBasicBlock - Start execution in a new basic block and run any
211  // PHI nodes in the top of the block.  This is used for intraprocedural
212  // control flow.
213  //
214  void SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF);
215
216  void *getPointerToFunction(Function *F) override { return (void*)F; }
217
218  void initializeExecutionEngine() { }
219  void initializeExternalFunctions();
220  GenericValue getConstantExprValue(ConstantExpr *CE, ExecutionContext &SF);
221  GenericValue getOperandValue(Value *V, ExecutionContext &SF);
222  GenericValue executeTruncInst(Value *SrcVal, Type *DstTy,
223                                ExecutionContext &SF);
224  GenericValue executeSExtInst(Value *SrcVal, Type *DstTy,
225                               ExecutionContext &SF);
226  GenericValue executeZExtInst(Value *SrcVal, Type *DstTy,
227                               ExecutionContext &SF);
228  GenericValue executeFPTruncInst(Value *SrcVal, Type *DstTy,
229                                  ExecutionContext &SF);
230  GenericValue executeFPExtInst(Value *SrcVal, Type *DstTy,
231                                ExecutionContext &SF);
232  GenericValue executeFPToUIInst(Value *SrcVal, Type *DstTy,
233                                 ExecutionContext &SF);
234  GenericValue executeFPToSIInst(Value *SrcVal, Type *DstTy,
235                                 ExecutionContext &SF);
236  GenericValue executeUIToFPInst(Value *SrcVal, Type *DstTy,
237                                 ExecutionContext &SF);
238  GenericValue executeSIToFPInst(Value *SrcVal, Type *DstTy,
239                                 ExecutionContext &SF);
240  GenericValue executePtrToIntInst(Value *SrcVal, Type *DstTy,
241                                   ExecutionContext &SF);
242  GenericValue executeIntToPtrInst(Value *SrcVal, Type *DstTy,
243                                   ExecutionContext &SF);
244  GenericValue executeBitCastInst(Value *SrcVal, Type *DstTy,
245                                  ExecutionContext &SF);
246  GenericValue executeCastOperation(Instruction::CastOps opcode, Value *SrcVal,
247                                    Type *Ty, ExecutionContext &SF);
248  void popStackAndReturnValueToCaller(Type *RetTy, GenericValue Result);
249
250};
251
252} // End llvm namespace
253
254#endif
255