Interpreter.h revision 2cab55d7e1bde83cd5f5dccee9a331ada8c1a67c 
1//===-- Interpreter.h ------------------------------------------*- C++ -*--===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source 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/Function.h"
18#include "llvm/ExecutionEngine/ExecutionEngine.h"
19#include "llvm/ExecutionEngine/GenericValue.h"
20#include "llvm/Support/InstVisitor.h"
21#include "llvm/Support/CallSite.h"
22#include "llvm/Target/TargetData.h"
23#include "Support/DataTypes.h"
24
25namespace llvm {
26
27struct FunctionInfo;        // Defined in ExecutionAnnotations.h
28class gep_type_iterator;
29class ConstantExpr;
30
31// AllocaHolder - Object to track all of the blocks of memory allocated by
32// alloca.  When the function returns, this object is popped off the execution
33// stack, which causes the dtor to be run, which frees all the alloca'd memory.
34//
35class AllocaHolder {
36  friend class AllocaHolderHandle;
37  std::vector<void*> Allocations;
38  unsigned RefCnt;
39public:
40  AllocaHolder() : RefCnt(0) {}
41  void add(void *mem) { Allocations.push_back(mem); }
42  ~AllocaHolder() {
43    for (unsigned i = 0; i < Allocations.size(); ++i)
44      free(Allocations[i]);
45  }
46};
47
48// AllocaHolderHandle gives AllocaHolder value semantics so we can stick it into
49// a vector...
50//
51class AllocaHolderHandle {
52  AllocaHolder *H;
53public:
54  AllocaHolderHandle() : H(new AllocaHolder()) { H->RefCnt++; }
55  AllocaHolderHandle(const AllocaHolderHandle &AH) : H(AH.H) { H->RefCnt++; }
56  ~AllocaHolderHandle() { if (--H->RefCnt == 0) delete H; }
57
58  void add(void *mem) { H->add(mem); }
59};
60
61typedef std::vector<GenericValue> ValuePlaneTy;
62
63// ExecutionContext struct - This struct represents one stack frame currently
64// executing.
65//
66struct ExecutionContext {
67  Function             *CurFunction;// The currently executing function
68  BasicBlock           *CurBB;      // The currently executing BB
69  BasicBlock::iterator  CurInst;    // The next instruction to execute
70  std::map<Value *, GenericValue> Values; // LLVM values used in this invocation
71  std::vector<GenericValue>  VarArgs; // Values passed through an ellipsis
72  CallSite             Caller;     // Holds the call that called subframes.
73                                   // NULL if main func or debugger invoked fn
74  AllocaHolderHandle    Allocas;    // Track memory allocated by alloca
75};
76
77// Interpreter - This class represents the entirety of the interpreter.
78//
79class Interpreter : public ExecutionEngine, public InstVisitor<Interpreter> {
80  int ExitCode;                // The exit code to be returned by the lli util
81  TargetData TD;
82
83  // The runtime stack of executing code.  The top of the stack is the current
84  // function record.
85  std::vector<ExecutionContext> ECStack;
86
87  // AtExitHandlers - List of functions to call when the program exits,
88  // registered with the atexit() library function.
89  std::vector<Function*> AtExitHandlers;
90
91public:
92  Interpreter(Module *M, bool isLittleEndian, bool isLongPointer);
93  inline ~Interpreter() { }
94
95  /// runAtExitHandlers - Run any functions registered by the program's calls to
96  /// atexit(3), which we intercept and store in AtExitHandlers.
97  ///
98  void runAtExitHandlers();
99
100  /// create - Create an interpreter ExecutionEngine. This can never fail.
101  ///
102  static ExecutionEngine *create(Module *M);
103
104  /// run - Start execution with the specified function and arguments.
105  ///
106  virtual GenericValue runFunction(Function *F,
107                                   const std::vector<GenericValue> &ArgValues);
108
109  /// recompileAndRelinkFunction - For the interpreter, functions are always
110  /// up-to-date.
111  ///
112  virtual void *recompileAndRelinkFunction(Function *F) {
113    return getPointerToFunction(F);
114  }
115
116  // Methods used to execute code:
117  // Place a call on the stack
118  void callFunction(Function *F, const std::vector<GenericValue> &ArgVals);
119  void run();                // Execute instructions until nothing left to do
120
121  // Opcode Implementations
122  void visitReturnInst(ReturnInst &I);
123  void visitBranchInst(BranchInst &I);
124  void visitSwitchInst(SwitchInst &I);
125
126  void visitBinaryOperator(BinaryOperator &I);
127  void visitAllocationInst(AllocationInst &I);
128  void visitFreeInst(FreeInst &I);
129  void visitLoadInst(LoadInst &I);
130  void visitStoreInst(StoreInst &I);
131  void visitGetElementPtrInst(GetElementPtrInst &I);
132  void visitPHINode(PHINode &PN) { assert(0 && "PHI nodes already handled!"); }
133  void visitCastInst(CastInst &I);
134
135  void visitCallSite(CallSite CS);
136  void visitCallInst(CallInst &I) { visitCallSite (CallSite (&I)); }
137  void visitInvokeInst(InvokeInst &I) { visitCallSite (CallSite (&I)); }
138  void visitUnwindInst(UnwindInst &I);
139
140  void visitShl(ShiftInst &I);
141  void visitShr(ShiftInst &I);
142  void visitVANextInst(VANextInst &I);
143  void visitVAArgInst(VAArgInst &I);
144  void visitInstruction(Instruction &I) {
145    std::cerr << I;
146    assert(0 && "Instruction not interpretable yet!");
147  }
148
149  GenericValue callExternalFunction(Function *F,
150                                    const std::vector<GenericValue> &ArgVals);
151  void exitCalled(GenericValue GV);
152
153  void addAtExitHandler(Function *F) {
154    AtExitHandlers.push_back(F);
155  }
156
157  GenericValue *getFirstVarArg () {
158    return &(ECStack[ECStack.size () - 2].VarArgs[0]);
159  }
160
161  //FIXME: private:
162public:
163  GenericValue executeGEPOperation(Value *Ptr, gep_type_iterator I,
164				   gep_type_iterator E, ExecutionContext &SF);
165
166private:  // Helper functions
167  // SwitchToNewBasicBlock - Start execution in a new basic block and run any
168  // PHI nodes in the top of the block.  This is used for intraprocedural
169  // control flow.
170  //
171  void SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF);
172
173  void *getPointerToFunction(Function *F) { return (void*)F; }
174
175  void initializeExecutionEngine();
176  void initializeExternalFunctions();
177  GenericValue getConstantExprValue(ConstantExpr *CE, ExecutionContext &SF);
178  GenericValue getOperandValue(Value *V, ExecutionContext &SF);
179  GenericValue executeCastOperation(Value *SrcVal, const Type *Ty,
180				    ExecutionContext &SF);
181  void popStackAndReturnValueToCaller(const Type *RetTy, GenericValue Result);
182};
183
184} // End llvm namespace
185
186#endif
187