Interpreter.h revision 36b56886974eae4f9c5ebc96befd3e7bfe5de338 
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 LLI_INTERPRETER_H
15#define LLI_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;
29struct FunctionInfo;
30template<typename T> class generic_gep_type_iterator;
31class ConstantExpr;
32typedef generic_gep_type_iterator<User::const_op_iterator> gep_type_iterator;
33
34
35// AllocaHolder - Object to track all of the blocks of memory allocated by
36// alloca.  When the function returns, this object is popped off the execution
37// stack, which causes the dtor to be run, which frees all the alloca'd memory.
38//
39class AllocaHolder {
40  friend class AllocaHolderHandle;
41  std::vector<void*> Allocations;
42  unsigned RefCnt;
43public:
44  AllocaHolder() : RefCnt(0) {}
45  void add(void *mem) { Allocations.push_back(mem); }
46  ~AllocaHolder() {
47    for (unsigned i = 0; i < Allocations.size(); ++i)
48      free(Allocations[i]);
49  }
50};
51
52// AllocaHolderHandle gives AllocaHolder value semantics so we can stick it into
53// a vector...
54//
55class AllocaHolderHandle {
56  AllocaHolder *H;
57public:
58  AllocaHolderHandle() : H(new AllocaHolder()) { H->RefCnt++; }
59  AllocaHolderHandle(const AllocaHolderHandle &AH) : H(AH.H) { H->RefCnt++; }
60  ~AllocaHolderHandle() { if (--H->RefCnt == 0) delete H; }
61
62  void add(void *mem) { H->add(mem); }
63};
64
65typedef std::vector<GenericValue> ValuePlaneTy;
66
67// ExecutionContext struct - This struct represents one stack frame currently
68// executing.
69//
70struct ExecutionContext {
71  Function             *CurFunction;// The currently executing function
72  BasicBlock           *CurBB;      // The currently executing BB
73  BasicBlock::iterator  CurInst;    // The next instruction to execute
74  std::map<Value *, GenericValue> Values; // LLVM values used in this invocation
75  std::vector<GenericValue>  VarArgs; // Values passed through an ellipsis
76  CallSite             Caller;     // Holds the call that called subframes.
77                                   // NULL if main func or debugger invoked fn
78  AllocaHolderHandle    Allocas;    // Track memory allocated by alloca
79};
80
81// Interpreter - This class represents the entirety of the interpreter.
82//
83class Interpreter : public ExecutionEngine, public InstVisitor<Interpreter> {
84  GenericValue ExitValue;          // The return value of the called function
85  DataLayout TD;
86  IntrinsicLowering *IL;
87
88  // The runtime stack of executing code.  The top of the stack is the current
89  // function record.
90  std::vector<ExecutionContext> ECStack;
91
92  // AtExitHandlers - List of functions to call when the program exits,
93  // registered with the atexit() library function.
94  std::vector<Function*> AtExitHandlers;
95
96public:
97  explicit Interpreter(Module *M);
98  ~Interpreter();
99
100  /// runAtExitHandlers - Run any functions registered by the program's calls to
101  /// atexit(3), which we intercept and store in AtExitHandlers.
102  ///
103  void runAtExitHandlers();
104
105  static void Register() {
106    InterpCtor = create;
107  }
108
109  /// create - Create an interpreter ExecutionEngine. This can never fail.
110  ///
111  static ExecutionEngine *create(Module *M, std::string *ErrorStr = 0);
112
113  /// run - Start execution with the specified function and arguments.
114  ///
115  GenericValue runFunction(Function *F,
116                           const std::vector<GenericValue> &ArgValues) override;
117
118  void *getPointerToNamedFunction(const std::string &Name,
119                                  bool AbortOnFailure = true) override {
120    // FIXME: not implemented.
121    return 0;
122  }
123
124  /// recompileAndRelinkFunction - For the interpreter, functions are always
125  /// up-to-date.
126  ///
127  void *recompileAndRelinkFunction(Function *F) override {
128    return getPointerToFunction(F);
129  }
130
131  /// freeMachineCodeForFunction - The interpreter does not generate any code.
132  ///
133  void freeMachineCodeForFunction(Function *F) override { }
134
135  // Methods used to execute code:
136  // Place a call on the stack
137  void callFunction(Function *F, const std::vector<GenericValue> &ArgVals);
138  void run();                // Execute instructions until nothing left to do
139
140  // Opcode Implementations
141  void visitReturnInst(ReturnInst &I);
142  void visitBranchInst(BranchInst &I);
143  void visitSwitchInst(SwitchInst &I);
144  void visitIndirectBrInst(IndirectBrInst &I);
145
146  void visitBinaryOperator(BinaryOperator &I);
147  void visitICmpInst(ICmpInst &I);
148  void visitFCmpInst(FCmpInst &I);
149  void visitAllocaInst(AllocaInst &I);
150  void visitLoadInst(LoadInst &I);
151  void visitStoreInst(StoreInst &I);
152  void visitGetElementPtrInst(GetElementPtrInst &I);
153  void visitPHINode(PHINode &PN) {
154    llvm_unreachable("PHI nodes already handled!");
155  }
156  void visitTruncInst(TruncInst &I);
157  void visitZExtInst(ZExtInst &I);
158  void visitSExtInst(SExtInst &I);
159  void visitFPTruncInst(FPTruncInst &I);
160  void visitFPExtInst(FPExtInst &I);
161  void visitUIToFPInst(UIToFPInst &I);
162  void visitSIToFPInst(SIToFPInst &I);
163  void visitFPToUIInst(FPToUIInst &I);
164  void visitFPToSIInst(FPToSIInst &I);
165  void visitPtrToIntInst(PtrToIntInst &I);
166  void visitIntToPtrInst(IntToPtrInst &I);
167  void visitBitCastInst(BitCastInst &I);
168  void visitSelectInst(SelectInst &I);
169
170
171  void visitCallSite(CallSite CS);
172  void visitCallInst(CallInst &I) { visitCallSite (CallSite (&I)); }
173  void visitInvokeInst(InvokeInst &I) { visitCallSite (CallSite (&I)); }
174  void visitUnreachableInst(UnreachableInst &I);
175
176  void visitShl(BinaryOperator &I);
177  void visitLShr(BinaryOperator &I);
178  void visitAShr(BinaryOperator &I);
179
180  void visitVAArgInst(VAArgInst &I);
181  void visitExtractElementInst(ExtractElementInst &I);
182  void visitInsertElementInst(InsertElementInst &I);
183  void visitShuffleVectorInst(ShuffleVectorInst &I);
184
185  void visitExtractValueInst(ExtractValueInst &I);
186  void visitInsertValueInst(InsertValueInst &I);
187
188  void visitInstruction(Instruction &I) {
189    errs() << I << "\n";
190    llvm_unreachable("Instruction not interpretable yet!");
191  }
192
193  GenericValue callExternalFunction(Function *F,
194                                    const std::vector<GenericValue> &ArgVals);
195  void exitCalled(GenericValue GV);
196
197  void addAtExitHandler(Function *F) {
198    AtExitHandlers.push_back(F);
199  }
200
201  GenericValue *getFirstVarArg () {
202    return &(ECStack.back ().VarArgs[0]);
203  }
204
205private:  // Helper functions
206  GenericValue executeGEPOperation(Value *Ptr, gep_type_iterator I,
207                                   gep_type_iterator E, ExecutionContext &SF);
208
209  // SwitchToNewBasicBlock - Start execution in a new basic block and run any
210  // PHI nodes in the top of the block.  This is used for intraprocedural
211  // control flow.
212  //
213  void SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF);
214
215  void *getPointerToFunction(Function *F) override { return (void*)F; }
216  void *getPointerToBasicBlock(BasicBlock *BB) override { return (void*)BB; }
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