lib/ExecutionEngine/Interpreter/Interpreter.h

   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/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 "llvm/Support/DataTypes.h"
  24
  25 namespace llvm {
  26
  27 class IntrinsicLowering;
  28 struct FunctionInfo;
  29 template<typename T> class generic_gep_type_iterator;
  30 class ConstantExpr;
  31 typedef 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 //
  38 class AllocaHolder {
  39   friend class AllocaHolderHandle;
  40   std::vector<void*> Allocations;
  41   unsigned RefCnt;
  42 public:
  43   AllocaHolder() : RefCnt(0) {}
  44   void add(void *mem) { Allocations.push_back(mem); }
  45   ~AllocaHolder() {
  46     for (unsigned i = 0; i < Allocations.size(); ++i)
  47       free(Allocations[i]);
  48   }
  49 };
  50
  51 // AllocaHolderHandle gives AllocaHolder value semantics so we can stick it into
  52 // a vector...
  53 //
  54 class AllocaHolderHandle {
  55   AllocaHolder *H;
  56 public:
  57   AllocaHolderHandle() : H(new AllocaHolder()) { H->RefCnt++; }
  58   AllocaHolderHandle(const AllocaHolderHandle &AH) : H(AH.H) { H->RefCnt++; }
  59   ~AllocaHolderHandle() { if (--H->RefCnt == 0) delete H; }
  60
  61   void add(void *mem) { H->add(mem); }
  62 };
  63
  64 typedef std::vector<GenericValue> ValuePlaneTy;
  65
  66 // ExecutionContext struct - This struct represents one stack frame currently
  67 // executing.
  68 //
  69 struct ExecutionContext {
  70   Function             *CurFunction;// The currently executing function
  71   BasicBlock           *CurBB;      // The currently executing BB
  72   BasicBlock::iterator  CurInst;    // The next instruction to execute
  73   std::map<Value *, GenericValue> Values; // LLVM values used in this invocation
  74   std::vector<GenericValue>  VarArgs; // Values passed through an ellipsis
  75   CallSite             Caller;     // Holds the call that called subframes.
  76                                    // NULL if main func or debugger invoked fn
  77   AllocaHolderHandle    Allocas;    // Track memory allocated by alloca
  78 };
  79
  80 // Interpreter - This class represents the entirety of the interpreter.
  81 //
  82 class Interpreter : public ExecutionEngine, public InstVisitor<Interpreter> {
  83   GenericValue ExitValue;          // The return value of the called function
  84   TargetData TD;
  85   IntrinsicLowering *IL;
  86
  87   // The runtime stack of executing code.  The top of the stack is the current
  88   // function record.
  89   std::vector<ExecutionContext> ECStack;
  90
  91   // AtExitHandlers - List of functions to call when the program exits,
  92   // registered with the atexit() library function.
  93   std::vector<Function*> AtExitHandlers;
  94
  95 public:
  96   explicit Interpreter(ModuleProvider *M);
  97   ~Interpreter();
  98
  99   /// runAtExitHandlers - Run any functions registered by the program's calls to
 100   /// atexit(3), which we intercept and store in AtExitHandlers.
 101   ///
 102   void runAtExitHandlers();
 103
 104   static void Register() {
 105     InterpCtor = create;
 106   }
 107
 108   /// create - Create an interpreter ExecutionEngine. This can never fail.
 109   ///
 110   static ExecutionEngine *create(ModuleProvider *M, std::string *ErrorStr = 0,
 111                                  CodeGenOpt::Level = CodeGenOpt::Default);
 112
 113   /// run - Start execution with the specified function and arguments.
 114   ///
 115   virtual GenericValue runFunction(Function *F,
 116                                    const std::vector<GenericValue> &ArgValues);
 117
 118   /// recompileAndRelinkFunction - For the interpreter, functions are always
 119   /// up-to-date.
 120   ///
 121   virtual void *recompileAndRelinkFunction(Function *F) {
 122     return getPointerToFunction(F);
 123   }
 124
 125   /// freeMachineCodeForFunction - The interpreter does not generate any code.
 126   ///
 127   void freeMachineCodeForFunction(Function *F) { }
 128
 129   // Methods used to execute code:
 130   // Place a call on the stack
 131   void callFunction(Function *F, const std::vector<GenericValue> &ArgVals);
 132   void run();                // Execute instructions until nothing left to do
 133
 134   // Opcode Implementations
 135   void visitReturnInst(ReturnInst &I);
 136   void visitBranchInst(BranchInst &I);
 137   void visitSwitchInst(SwitchInst &I);
 138
 139   void visitBinaryOperator(BinaryOperator &I);
 140   void visitICmpInst(ICmpInst &I);
 141   void visitFCmpInst(FCmpInst &I);
 142   void visitAllocationInst(AllocationInst &I);
 143   void visitFreeInst(FreeInst &I);
 144   void visitLoadInst(LoadInst &I);
 145   void visitStoreInst(StoreInst &I);
 146   void visitGetElementPtrInst(GetElementPtrInst &I);
 147   void visitPHINode(PHINode &PN) { assert(0 && "PHI nodes already handled!"); }
 148   void visitTruncInst(TruncInst &I);
 149   void visitZExtInst(ZExtInst &I);
 150   void visitSExtInst(SExtInst &I);
 151   void visitFPTruncInst(FPTruncInst &I);
 152   void visitFPExtInst(FPExtInst &I);
 153   void visitUIToFPInst(UIToFPInst &I);
 154   void visitSIToFPInst(SIToFPInst &I);
 155   void visitFPToUIInst(FPToUIInst &I);
 156   void visitFPToSIInst(FPToSIInst &I);
 157   void visitPtrToIntInst(PtrToIntInst &I);
 158   void visitIntToPtrInst(IntToPtrInst &I);
 159   void visitBitCastInst(BitCastInst &I);
 160   void visitSelectInst(SelectInst &I);
 161
 162
 163   void visitCallSite(CallSite CS);
 164   void visitCallInst(CallInst &I) { visitCallSite (CallSite (&I)); }
 165   void visitInvokeInst(InvokeInst &I) { visitCallSite (CallSite (&I)); }
 166   void visitUnwindInst(UnwindInst &I);
 167   void visitUnreachableInst(UnreachableInst &I);
 168
 169   void visitShl(BinaryOperator &I);
 170   void visitLShr(BinaryOperator &I);
 171   void visitAShr(BinaryOperator &I);
 172
 173   void visitVAArgInst(VAArgInst &I);
 174   void visitInstruction(Instruction &I) {
 175     cerr << I;
 176     assert(0 && "Instruction not interpretable yet!");
 177   }
 178
 179   GenericValue callExternalFunction(Function *F,
 180                                     const std::vector<GenericValue> &ArgVals);
 181   void exitCalled(GenericValue GV);
 182
 183   void addAtExitHandler(Function *F) {
 184     AtExitHandlers.push_back(F);
 185   }
 186
 187   GenericValue *getFirstVarArg () {
 188     return &(ECStack.back ().VarArgs[0]);
 189   }
 190
 191   //FIXME: private:
 192 public:
 193   GenericValue executeGEPOperation(Value *Ptr, gep_type_iterator I,
 194                                    gep_type_iterator E, ExecutionContext &SF);
 195
 196 private:  // Helper functions
 197   // SwitchToNewBasicBlock - Start execution in a new basic block and run any
 198   // PHI nodes in the top of the block.  This is used for intraprocedural
 199   // control flow.
 200   //
 201   void SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF);
 202
 203   void *getPointerToFunction(Function *F) { return (void*)F; }
 204
 205   void initializeExecutionEngine();
 206   void initializeExternalFunctions();
 207   GenericValue getConstantExprValue(ConstantExpr *CE, ExecutionContext &SF);
 208   GenericValue getOperandValue(Value *V, ExecutionContext &SF);
 209   GenericValue executeTruncInst(Value *SrcVal, const Type *DstTy,
 210                                 ExecutionContext &SF);
 211   GenericValue executeSExtInst(Value *SrcVal, const Type *DstTy,
 212                                ExecutionContext &SF);
 213   GenericValue executeZExtInst(Value *SrcVal, const Type *DstTy,
 214                                ExecutionContext &SF);
 215   GenericValue executeFPTruncInst(Value *SrcVal, const Type *DstTy,
 216                                   ExecutionContext &SF);
 217   GenericValue executeFPExtInst(Value *SrcVal, const Type *DstTy,
 218                                 ExecutionContext &SF);
 219   GenericValue executeFPToUIInst(Value *SrcVal, const Type *DstTy,
 220                                  ExecutionContext &SF);
 221   GenericValue executeFPToSIInst(Value *SrcVal, const Type *DstTy,
 222                                  ExecutionContext &SF);
 223   GenericValue executeUIToFPInst(Value *SrcVal, const Type *DstTy,
 224                                  ExecutionContext &SF);
 225   GenericValue executeSIToFPInst(Value *SrcVal, const Type *DstTy,
 226                                  ExecutionContext &SF);
 227   GenericValue executePtrToIntInst(Value *SrcVal, const Type *DstTy,
 228                                    ExecutionContext &SF);
 229   GenericValue executeIntToPtrInst(Value *SrcVal, const Type *DstTy,
 230                                    ExecutionContext &SF);
 231   GenericValue executeBitCastInst(Value *SrcVal, const Type *DstTy,
 232                                   ExecutionContext &SF);
 233   GenericValue executeCastOperation(Instruction::CastOps opcode, Value *SrcVal,
 234                                     const Type *Ty, ExecutionContext &SF);
 235   void popStackAndReturnValueToCaller(const Type *RetTy, GenericValue Result);
 236
 237 };
 238
 239 } // End llvm namespace
 240
 241 #endif