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"
25namespace llvm {
26
27class IntrinsicLowering;
28template<typename T> class generic_gep_type_iterator;
29class ConstantExpr;
30typedef 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//
37class AllocaHolder {
38 std::vector<void *> Allocations;
39
40public:
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
55typedef std::vector<GenericValue> ValuePlaneTy;
56
57// ExecutionContext struct - This struct represents one stack frame currently
58// executing.
59//
60struct 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//
75class 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
87public:
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
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 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