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"
24namespace llvm {
25
26class IntrinsicLowering;
27template<typename T> class generic_gep_type_iterator;
28class ConstantExpr;
29typedef 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//
36class AllocaHolder {
37 std::vector<void *> Allocations;
38
39public:
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(ptr: Allocation);
49 }
50
51 void add(void *Mem) { Allocations.push_back(x: Mem); }
52};
53
54typedef std::vector<GenericValue> ValuePlaneTy;
55
56// ExecutionContext struct - This struct represents one stack frame currently
57// executing.
58//
59struct 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//
74class 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
86public:
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(x: F);
181 }
182
183 GenericValue *getFirstVarArg () {
184 return &(ECStack.back ().VarArgs[0]);
185 }
186
187private: // 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