LLVM API Documentation
00001 //===-- Interpreter.h ------------------------------------------*- C++ -*--===// 00002 // 00003 // The LLVM Compiler Infrastructure 00004 // 00005 // This file was developed by the LLVM research group and is distributed under 00006 // the University of Illinois Open Source License. See LICENSE.TXT for details. 00007 // 00008 //===----------------------------------------------------------------------===// 00009 // 00010 // This header file defines the interpreter structure 00011 // 00012 //===----------------------------------------------------------------------===// 00013 00014 #ifndef LLI_INTERPRETER_H 00015 #define LLI_INTERPRETER_H 00016 00017 #include "llvm/Function.h" 00018 #include "llvm/ExecutionEngine/ExecutionEngine.h" 00019 #include "llvm/ExecutionEngine/GenericValue.h" 00020 #include "llvm/Support/InstVisitor.h" 00021 #include "llvm/Support/CallSite.h" 00022 #include "llvm/Target/TargetData.h" 00023 #include "llvm/Support/DataTypes.h" 00024 #include <iostream> 00025 00026 namespace llvm { 00027 00028 class IntrinsicLowering; 00029 struct FunctionInfo; 00030 template<typename T> class generic_gep_type_iterator; 00031 class ConstantExpr; 00032 typedef generic_gep_type_iterator<User::const_op_iterator> gep_type_iterator; 00033 00034 00035 // AllocaHolder - Object to track all of the blocks of memory allocated by 00036 // alloca. When the function returns, this object is popped off the execution 00037 // stack, which causes the dtor to be run, which frees all the alloca'd memory. 00038 // 00039 class AllocaHolder { 00040 friend class AllocaHolderHandle; 00041 std::vector<void*> Allocations; 00042 unsigned RefCnt; 00043 public: 00044 AllocaHolder() : RefCnt(0) {} 00045 void add(void *mem) { Allocations.push_back(mem); } 00046 ~AllocaHolder() { 00047 for (unsigned i = 0; i < Allocations.size(); ++i) 00048 free(Allocations[i]); 00049 } 00050 }; 00051 00052 // AllocaHolderHandle gives AllocaHolder value semantics so we can stick it into 00053 // a vector... 00054 // 00055 class AllocaHolderHandle { 00056 AllocaHolder *H; 00057 public: 00058 AllocaHolderHandle() : H(new AllocaHolder()) { H->RefCnt++; } 00059 AllocaHolderHandle(const AllocaHolderHandle &AH) : H(AH.H) { H->RefCnt++; } 00060 ~AllocaHolderHandle() { if (--H->RefCnt == 0) delete H; } 00061 00062 void add(void *mem) { H->add(mem); } 00063 }; 00064 00065 typedef std::vector<GenericValue> ValuePlaneTy; 00066 00067 // ExecutionContext struct - This struct represents one stack frame currently 00068 // executing. 00069 // 00070 struct ExecutionContext { 00071 Function *CurFunction;// The currently executing function 00072 BasicBlock *CurBB; // The currently executing BB 00073 BasicBlock::iterator CurInst; // The next instruction to execute 00074 std::map<Value *, GenericValue> Values; // LLVM values used in this invocation 00075 std::vector<GenericValue> VarArgs; // Values passed through an ellipsis 00076 CallSite Caller; // Holds the call that called subframes. 00077 // NULL if main func or debugger invoked fn 00078 AllocaHolderHandle Allocas; // Track memory allocated by alloca 00079 }; 00080 00081 // Interpreter - This class represents the entirety of the interpreter. 00082 // 00083 class Interpreter : public ExecutionEngine, public InstVisitor<Interpreter> { 00084 GenericValue ExitValue; // The return value of the called function 00085 TargetData TD; 00086 IntrinsicLowering *IL; 00087 00088 // The runtime stack of executing code. The top of the stack is the current 00089 // function record. 00090 std::vector<ExecutionContext> ECStack; 00091 00092 // AtExitHandlers - List of functions to call when the program exits, 00093 // registered with the atexit() library function. 00094 std::vector<Function*> AtExitHandlers; 00095 00096 public: 00097 Interpreter(Module *M, bool isLittleEndian, bool isLongPointer); 00098 ~Interpreter(); 00099 00100 /// runAtExitHandlers - Run any functions registered by the program's calls to 00101 /// atexit(3), which we intercept and store in AtExitHandlers. 00102 /// 00103 void runAtExitHandlers(); 00104 00105 static void Register() { 00106 InterpCtor = create; 00107 } 00108 00109 /// create - Create an interpreter ExecutionEngine. This can never fail. 00110 /// 00111 static ExecutionEngine *create(ModuleProvider *M); 00112 00113 /// run - Start execution with the specified function and arguments. 00114 /// 00115 virtual GenericValue runFunction(Function *F, 00116 const std::vector<GenericValue> &ArgValues); 00117 00118 /// recompileAndRelinkFunction - For the interpreter, functions are always 00119 /// up-to-date. 00120 /// 00121 virtual void *recompileAndRelinkFunction(Function *F) { 00122 return getPointerToFunction(F); 00123 } 00124 00125 /// freeMachineCodeForFunction - The interpreter does not generate any code. 00126 /// 00127 void freeMachineCodeForFunction(Function *F) { } 00128 00129 // Methods used to execute code: 00130 // Place a call on the stack 00131 void callFunction(Function *F, const std::vector<GenericValue> &ArgVals); 00132 void run(); // Execute instructions until nothing left to do 00133 00134 // Opcode Implementations 00135 void visitReturnInst(ReturnInst &I); 00136 void visitBranchInst(BranchInst &I); 00137 void visitSwitchInst(SwitchInst &I); 00138 00139 void visitBinaryOperator(BinaryOperator &I); 00140 void visitAllocationInst(AllocationInst &I); 00141 void visitFreeInst(FreeInst &I); 00142 void visitLoadInst(LoadInst &I); 00143 void visitStoreInst(StoreInst &I); 00144 void visitGetElementPtrInst(GetElementPtrInst &I); 00145 void visitPHINode(PHINode &PN) { assert(0 && "PHI nodes already handled!"); } 00146 void visitCastInst(CastInst &I); 00147 void visitSelectInst(SelectInst &I); 00148 00149 00150 void visitCallSite(CallSite CS); 00151 void visitCallInst(CallInst &I) { visitCallSite (CallSite (&I)); } 00152 void visitInvokeInst(InvokeInst &I) { visitCallSite (CallSite (&I)); } 00153 void visitUnwindInst(UnwindInst &I); 00154 void visitUnreachableInst(UnreachableInst &I); 00155 00156 void visitShl(ShiftInst &I); 00157 void visitShr(ShiftInst &I); 00158 void visitVAArgInst(VAArgInst &I); 00159 void visitInstruction(Instruction &I) { 00160 std::cerr << I; 00161 assert(0 && "Instruction not interpretable yet!"); 00162 } 00163 00164 GenericValue callExternalFunction(Function *F, 00165 const std::vector<GenericValue> &ArgVals); 00166 void exitCalled(GenericValue GV); 00167 00168 void addAtExitHandler(Function *F) { 00169 AtExitHandlers.push_back(F); 00170 } 00171 00172 GenericValue *getFirstVarArg () { 00173 return &(ECStack.back ().VarArgs[0]); 00174 } 00175 00176 //FIXME: private: 00177 public: 00178 GenericValue executeGEPOperation(Value *Ptr, gep_type_iterator I, 00179 gep_type_iterator E, ExecutionContext &SF); 00180 00181 private: // Helper functions 00182 // SwitchToNewBasicBlock - Start execution in a new basic block and run any 00183 // PHI nodes in the top of the block. This is used for intraprocedural 00184 // control flow. 00185 // 00186 void SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF); 00187 00188 void *getPointerToFunction(Function *F) { return (void*)F; } 00189 00190 void initializeExecutionEngine(); 00191 void initializeExternalFunctions(); 00192 GenericValue getConstantExprValue(ConstantExpr *CE, ExecutionContext &SF); 00193 GenericValue getOperandValue(Value *V, ExecutionContext &SF); 00194 GenericValue executeCastOperation(Value *SrcVal, const Type *Ty, 00195 ExecutionContext &SF); 00196 void popStackAndReturnValueToCaller(const Type *RetTy, GenericValue Result); 00197 }; 00198 00199 } // End llvm namespace 00200 00201 #endif