1 //===-- Interpreter.h ------------------------------------------*- C++ -*--===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This header file defines the interpreter structure 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_LIB_EXECUTIONENGINE_INTERPRETER_INTERPRETER_H 14 #define LLVM_LIB_EXECUTIONENGINE_INTERPRETER_INTERPRETER_H 15 16 #include "llvm/ExecutionEngine/ExecutionEngine.h" 17 #include "llvm/ExecutionEngine/GenericValue.h" 18 #include "llvm/IR/DataLayout.h" 19 #include "llvm/IR/Function.h" 20 #include "llvm/IR/InstVisitor.h" 21 #include "llvm/Support/DataTypes.h" 22 #include "llvm/Support/ErrorHandling.h" 23 #include "llvm/Support/raw_ostream.h" 24 namespace llvm { 25 26 class IntrinsicLowering; 27 template<typename T> class generic_gep_type_iterator; 28 class ConstantExpr; 29 typedef generic_gep_type_iterator<User::const_op_iterator> gep_type_iterator; 30 31 32 // AllocaHolder - Object to track all of the blocks of memory allocated by 33 // alloca. When the function returns, this object is popped off the execution 34 // stack, which causes the dtor to be run, which frees all the alloca'd memory. 35 // 36 class AllocaHolder { 37 std::vector<void *> Allocations; 38 39 public: 40 AllocaHolder() = default; 41 42 // Make this type move-only. 43 AllocaHolder(AllocaHolder &&) = default; 44 AllocaHolder &operator=(AllocaHolder &&RHS) = default; 45 46 ~AllocaHolder() { 47 for (void *Allocation : Allocations) 48 free(Allocation); 49 } 50 51 void add(void *Mem) { Allocations.push_back(Mem); } 52 }; 53 54 typedef std::vector<GenericValue> ValuePlaneTy; 55 56 // ExecutionContext struct - This struct represents one stack frame currently 57 // executing. 58 // 59 struct ExecutionContext { 60 Function *CurFunction;// The currently executing function 61 BasicBlock *CurBB; // The currently executing BB 62 BasicBlock::iterator CurInst; // The next instruction to execute 63 CallBase *Caller; // Holds the call that called subframes. 64 // NULL if main func or debugger invoked fn 65 std::map<Value *, GenericValue> Values; // LLVM values used in this invocation 66 std::vector<GenericValue> VarArgs; // Values passed through an ellipsis 67 AllocaHolder Allocas; // Track memory allocated by alloca 68 69 ExecutionContext() : CurFunction(nullptr), CurBB(nullptr), CurInst(nullptr) {} 70 }; 71 72 // Interpreter - This class represents the entirety of the interpreter. 73 // 74 class Interpreter : public ExecutionEngine, public InstVisitor<Interpreter> { 75 GenericValue ExitValue; // The return value of the called function 76 IntrinsicLowering *IL; 77 78 // The runtime stack of executing code. The top of the stack is the current 79 // function record. 80 std::vector<ExecutionContext> ECStack; 81 82 // AtExitHandlers - List of functions to call when the program exits, 83 // registered with the atexit() library function. 84 std::vector<Function*> AtExitHandlers; 85 86 public: 87 explicit Interpreter(std::unique_ptr<Module> M); 88 ~Interpreter() override; 89 90 /// runAtExitHandlers - Run any functions registered by the program's calls to 91 /// atexit(3), which we intercept and store in AtExitHandlers. 92 /// 93 void runAtExitHandlers(); 94 95 static void Register() { 96 InterpCtor = create; 97 } 98 99 /// Create an interpreter ExecutionEngine. 100 /// 101 static ExecutionEngine *create(std::unique_ptr<Module> M, 102 std::string *ErrorStr = nullptr); 103 104 /// run - Start execution with the specified function and arguments. 105 /// 106 GenericValue runFunction(Function *F, 107 ArrayRef<GenericValue> ArgValues) override; 108 109 void *getPointerToNamedFunction(StringRef Name, 110 bool AbortOnFailure = true) override { 111 // FIXME: not implemented. 112 return nullptr; 113 } 114 115 // Methods used to execute code: 116 // Place a call on the stack 117 void callFunction(Function *F, ArrayRef<GenericValue> ArgVals); 118 void run(); // Execute instructions until nothing left to do 119 120 // Opcode Implementations 121 void visitReturnInst(ReturnInst &I); 122 void visitBranchInst(BranchInst &I); 123 void visitSwitchInst(SwitchInst &I); 124 void visitIndirectBrInst(IndirectBrInst &I); 125 126 void visitUnaryOperator(UnaryOperator &I); 127 void visitBinaryOperator(BinaryOperator &I); 128 void visitICmpInst(ICmpInst &I); 129 void visitFCmpInst(FCmpInst &I); 130 void visitAllocaInst(AllocaInst &I); 131 void visitLoadInst(LoadInst &I); 132 void visitStoreInst(StoreInst &I); 133 void visitGetElementPtrInst(GetElementPtrInst &I); 134 void visitPHINode(PHINode &PN) { 135 llvm_unreachable("PHI nodes already handled!"); 136 } 137 void visitTruncInst(TruncInst &I); 138 void visitZExtInst(ZExtInst &I); 139 void visitSExtInst(SExtInst &I); 140 void visitFPTruncInst(FPTruncInst &I); 141 void visitFPExtInst(FPExtInst &I); 142 void visitUIToFPInst(UIToFPInst &I); 143 void visitSIToFPInst(SIToFPInst &I); 144 void visitFPToUIInst(FPToUIInst &I); 145 void visitFPToSIInst(FPToSIInst &I); 146 void visitPtrToIntInst(PtrToIntInst &I); 147 void visitIntToPtrInst(IntToPtrInst &I); 148 void visitBitCastInst(BitCastInst &I); 149 void visitSelectInst(SelectInst &I); 150 151 void visitVAStartInst(VAStartInst &I); 152 void visitVAEndInst(VAEndInst &I); 153 void visitVACopyInst(VACopyInst &I); 154 void visitIntrinsicInst(IntrinsicInst &I); 155 void visitCallBase(CallBase &I); 156 void visitUnreachableInst(UnreachableInst &I); 157 158 void visitShl(BinaryOperator &I); 159 void visitLShr(BinaryOperator &I); 160 void visitAShr(BinaryOperator &I); 161 162 void visitVAArgInst(VAArgInst &I); 163 void visitExtractElementInst(ExtractElementInst &I); 164 void visitInsertElementInst(InsertElementInst &I); 165 void visitShuffleVectorInst(ShuffleVectorInst &I); 166 167 void visitExtractValueInst(ExtractValueInst &I); 168 void visitInsertValueInst(InsertValueInst &I); 169 170 void visitInstruction(Instruction &I) { 171 errs() << I << "\n"; 172 llvm_unreachable("Instruction not interpretable yet!"); 173 } 174 175 GenericValue callExternalFunction(Function *F, 176 ArrayRef<GenericValue> ArgVals); 177 void exitCalled(GenericValue GV); 178 179 void addAtExitHandler(Function *F) { 180 AtExitHandlers.push_back(F); 181 } 182 183 GenericValue *getFirstVarArg () { 184 return &(ECStack.back ().VarArgs[0]); 185 } 186 187 private: // Helper functions 188 GenericValue executeGEPOperation(Value *Ptr, gep_type_iterator I, 189 gep_type_iterator E, ExecutionContext &SF); 190 191 // SwitchToNewBasicBlock - Start execution in a new basic block and run any 192 // PHI nodes in the top of the block. This is used for intraprocedural 193 // control flow. 194 // 195 void SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF); 196 197 void *getPointerToFunction(Function *F) override { return (void*)F; } 198 199 void initializeExecutionEngine() { } 200 void initializeExternalFunctions(); 201 GenericValue getConstantExprValue(ConstantExpr *CE, ExecutionContext &SF); 202 GenericValue getOperandValue(Value *V, ExecutionContext &SF); 203 GenericValue executeTruncInst(Value *SrcVal, Type *DstTy, 204 ExecutionContext &SF); 205 GenericValue executeSExtInst(Value *SrcVal, Type *DstTy, 206 ExecutionContext &SF); 207 GenericValue executeZExtInst(Value *SrcVal, Type *DstTy, 208 ExecutionContext &SF); 209 GenericValue executeFPTruncInst(Value *SrcVal, Type *DstTy, 210 ExecutionContext &SF); 211 GenericValue executeFPExtInst(Value *SrcVal, Type *DstTy, 212 ExecutionContext &SF); 213 GenericValue executeFPToUIInst(Value *SrcVal, Type *DstTy, 214 ExecutionContext &SF); 215 GenericValue executeFPToSIInst(Value *SrcVal, Type *DstTy, 216 ExecutionContext &SF); 217 GenericValue executeUIToFPInst(Value *SrcVal, Type *DstTy, 218 ExecutionContext &SF); 219 GenericValue executeSIToFPInst(Value *SrcVal, Type *DstTy, 220 ExecutionContext &SF); 221 GenericValue executePtrToIntInst(Value *SrcVal, Type *DstTy, 222 ExecutionContext &SF); 223 GenericValue executeIntToPtrInst(Value *SrcVal, Type *DstTy, 224 ExecutionContext &SF); 225 GenericValue executeBitCastInst(Value *SrcVal, Type *DstTy, 226 ExecutionContext &SF); 227 void popStackAndReturnValueToCaller(Type *RetTy, GenericValue Result); 228 229 }; 230 231 } // End llvm namespace 232 233 #endif 234