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/CallSite.h" 19 #include "llvm/IR/DataLayout.h" 20 #include "llvm/IR/Function.h" 21 #include "llvm/IR/InstVisitor.h" 22 #include "llvm/Support/DataTypes.h" 23 #include "llvm/Support/ErrorHandling.h" 24 #include "llvm/Support/raw_ostream.h" 25 namespace llvm { 26 27 class IntrinsicLowering; 28 template<typename T> class generic_gep_type_iterator; 29 class ConstantExpr; 30 typedef generic_gep_type_iterator<User::const_op_iterator> gep_type_iterator; 31 32 33 // AllocaHolder - Object to track all of the blocks of memory allocated by 34 // alloca. When the function returns, this object is popped off the execution 35 // stack, which causes the dtor to be run, which frees all the alloca'd memory. 36 // 37 class AllocaHolder { 38 std::vector<void *> Allocations; 39 40 public: 41 AllocaHolder() {} 42 43 // Make this type move-only. 44 AllocaHolder(AllocaHolder &&) = default; 45 AllocaHolder &operator=(AllocaHolder &&RHS) = default; 46 47 ~AllocaHolder() { 48 for (void *Allocation : Allocations) 49 free(Allocation); 50 } 51 52 void add(void *Mem) { Allocations.push_back(Mem); } 53 }; 54 55 typedef std::vector<GenericValue> ValuePlaneTy; 56 57 // ExecutionContext struct - This struct represents one stack frame currently 58 // executing. 59 // 60 struct ExecutionContext { 61 Function *CurFunction;// The currently executing function 62 BasicBlock *CurBB; // The currently executing BB 63 BasicBlock::iterator CurInst; // The next instruction to execute 64 CallSite Caller; // Holds the call that called subframes. 65 // NULL if main func or debugger invoked fn 66 std::map<Value *, GenericValue> Values; // LLVM values used in this invocation 67 std::vector<GenericValue> VarArgs; // Values passed through an ellipsis 68 AllocaHolder Allocas; // Track memory allocated by alloca 69 70 ExecutionContext() : CurFunction(nullptr), CurBB(nullptr), CurInst(nullptr) {} 71 }; 72 73 // Interpreter - This class represents the entirety of the interpreter. 74 // 75 class Interpreter : public ExecutionEngine, public InstVisitor<Interpreter> { 76 GenericValue ExitValue; // The return value of the called function 77 IntrinsicLowering *IL; 78 79 // The runtime stack of executing code. The top of the stack is the current 80 // function record. 81 std::vector<ExecutionContext> ECStack; 82 83 // AtExitHandlers - List of functions to call when the program exits, 84 // registered with the atexit() library function. 85 std::vector<Function*> AtExitHandlers; 86 87 public: 88 explicit Interpreter(std::unique_ptr<Module> M); 89 ~Interpreter() override; 90 91 /// runAtExitHandlers - Run any functions registered by the program's calls to 92 /// atexit(3), which we intercept and store in AtExitHandlers. 93 /// 94 void runAtExitHandlers(); 95 96 static void Register() { 97 InterpCtor = create; 98 } 99 100 /// Create an interpreter ExecutionEngine. 101 /// 102 static ExecutionEngine *create(std::unique_ptr<Module> M, 103 std::string *ErrorStr = nullptr); 104 105 /// run - Start execution with the specified function and arguments. 106 /// 107 GenericValue runFunction(Function *F, 108 ArrayRef<GenericValue> ArgValues) override; 109 110 void *getPointerToNamedFunction(StringRef Name, 111 bool AbortOnFailure = true) override { 112 // FIXME: not implemented. 113 return nullptr; 114 } 115 116 // Methods used to execute code: 117 // Place a call on the stack 118 void callFunction(Function *F, ArrayRef<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 void visitIndirectBrInst(IndirectBrInst &I); 126 127 void visitUnaryOperator(UnaryOperator &I); 128 void visitBinaryOperator(BinaryOperator &I); 129 void visitICmpInst(ICmpInst &I); 130 void visitFCmpInst(FCmpInst &I); 131 void visitAllocaInst(AllocaInst &I); 132 void visitLoadInst(LoadInst &I); 133 void visitStoreInst(StoreInst &I); 134 void visitGetElementPtrInst(GetElementPtrInst &I); 135 void visitPHINode(PHINode &PN) { 136 llvm_unreachable("PHI nodes already handled!"); 137 } 138 void visitTruncInst(TruncInst &I); 139 void visitZExtInst(ZExtInst &I); 140 void visitSExtInst(SExtInst &I); 141 void visitFPTruncInst(FPTruncInst &I); 142 void visitFPExtInst(FPExtInst &I); 143 void visitUIToFPInst(UIToFPInst &I); 144 void visitSIToFPInst(SIToFPInst &I); 145 void visitFPToUIInst(FPToUIInst &I); 146 void visitFPToSIInst(FPToSIInst &I); 147 void visitPtrToIntInst(PtrToIntInst &I); 148 void visitIntToPtrInst(IntToPtrInst &I); 149 void visitBitCastInst(BitCastInst &I); 150 void visitSelectInst(SelectInst &I); 151 152 153 void visitCallSite(CallSite CS); 154 void visitCallInst(CallInst &I) { visitCallSite (CallSite (&I)); } 155 void visitInvokeInst(InvokeInst &I) { visitCallSite (CallSite (&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 GenericValue executeCastOperation(Instruction::CastOps opcode, Value *SrcVal, 228 Type *Ty, ExecutionContext &SF); 229 void popStackAndReturnValueToCaller(Type *RetTy, GenericValue Result); 230 231 }; 232 233 } // End llvm namespace 234 235 #endif 236