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//===-- Interpreter.h ------------------------------------------*- C++ -*--===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This header file defines the interpreter structure
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/ExecutionEngine/GenericValue.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InstVisitor.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
namespace llvm {
class IntrinsicLowering;
template<typename T> class generic_gep_type_iterator;
class ConstantExpr;
typedef generic_gep_type_iterator<User::const_op_iterator> gep_type_iterator;
// AllocaHolder - Object to track all of the blocks of memory allocated by
// alloca. When the function returns, this object is popped off the execution
// stack, which causes the dtor to be run, which frees all the alloca'd memory.
class AllocaHolder {
std::vector<void *> Allocations;
AllocaHolder() = default;
// Make this type move-only.
AllocaHolder(AllocaHolder &&) = default;
AllocaHolder &operator=(AllocaHolder &&RHS) = default;
~AllocaHolder() {
for (void *Allocation : Allocations)
void add(void *Mem) { Allocations.push_back(Mem); }
typedef std::vector<GenericValue> ValuePlaneTy;
// ExecutionContext struct - This struct represents one stack frame currently
// executing.
struct ExecutionContext {
Function *CurFunction;// The currently executing function
BasicBlock *CurBB; // The currently executing BB
BasicBlock::iterator CurInst; // The next instruction to execute
CallBase *Caller; // Holds the call that called subframes.
// NULL if main func or debugger invoked fn
std::map<Value *, GenericValue> Values; // LLVM values used in this invocation
std::vector<GenericValue> VarArgs; // Values passed through an ellipsis
AllocaHolder Allocas; // Track memory allocated by alloca
ExecutionContext() : CurFunction(nullptr), CurBB(nullptr), CurInst(nullptr) {}
// Interpreter - This class represents the entirety of the interpreter.
class Interpreter : public ExecutionEngine, public InstVisitor<Interpreter> {
GenericValue ExitValue; // The return value of the called function
IntrinsicLowering *IL;
// The runtime stack of executing code. The top of the stack is the current
// function record.
std::vector<ExecutionContext> ECStack;
// AtExitHandlers - List of functions to call when the program exits,
// registered with the atexit() library function.
std::vector<Function*> AtExitHandlers;
explicit Interpreter(std::unique_ptr<Module> M);
~Interpreter() override;
/// runAtExitHandlers - Run any functions registered by the program's calls to
/// atexit(3), which we intercept and store in AtExitHandlers.
void runAtExitHandlers();
static void Register() {
InterpCtor = create;
/// Create an interpreter ExecutionEngine.
static ExecutionEngine *create(std::unique_ptr<Module> M,
std::string *ErrorStr = nullptr);
/// run - Start execution with the specified function and arguments.
GenericValue runFunction(Function *F,
ArrayRef<GenericValue> ArgValues) override;
void *getPointerToNamedFunction(StringRef Name,
bool AbortOnFailure = true) override {
// FIXME: not implemented.
return nullptr;
// Methods used to execute code:
// Place a call on the stack
void callFunction(Function *F, ArrayRef<GenericValue> ArgVals);
void run(); // Execute instructions until nothing left to do
// Opcode Implementations
void visitReturnInst(ReturnInst &I);
void visitBranchInst(BranchInst &I);
void visitSwitchInst(SwitchInst &I);
void visitIndirectBrInst(IndirectBrInst &I);
void visitUnaryOperator(UnaryOperator &I);
void visitBinaryOperator(BinaryOperator &I);
void visitICmpInst(ICmpInst &I);
void visitFCmpInst(FCmpInst &I);
void visitAllocaInst(AllocaInst &I);
void visitLoadInst(LoadInst &I);
void visitStoreInst(StoreInst &I);
void visitGetElementPtrInst(GetElementPtrInst &I);
void visitPHINode(PHINode &PN) {
llvm_unreachable("PHI nodes already handled!");
void visitTruncInst(TruncInst &I);
void visitZExtInst(ZExtInst &I);
void visitSExtInst(SExtInst &I);
void visitFPTruncInst(FPTruncInst &I);
void visitFPExtInst(FPExtInst &I);
void visitUIToFPInst(UIToFPInst &I);
void visitSIToFPInst(SIToFPInst &I);
void visitFPToUIInst(FPToUIInst &I);
void visitFPToSIInst(FPToSIInst &I);
void visitPtrToIntInst(PtrToIntInst &I);
void visitIntToPtrInst(IntToPtrInst &I);
void visitBitCastInst(BitCastInst &I);
void visitSelectInst(SelectInst &I);
void visitVAStartInst(VAStartInst &I);
void visitVAEndInst(VAEndInst &I);
void visitVACopyInst(VACopyInst &I);
void visitIntrinsicInst(IntrinsicInst &I);
void visitCallBase(CallBase &I);
void visitUnreachableInst(UnreachableInst &I);
void visitShl(BinaryOperator &I);
void visitLShr(BinaryOperator &I);
void visitAShr(BinaryOperator &I);
void visitVAArgInst(VAArgInst &I);
void visitExtractElementInst(ExtractElementInst &I);
void visitInsertElementInst(InsertElementInst &I);
void visitShuffleVectorInst(ShuffleVectorInst &I);
void visitExtractValueInst(ExtractValueInst &I);
void visitInsertValueInst(InsertValueInst &I);
void visitInstruction(Instruction &I) {
errs() << I << "\n";
llvm_unreachable("Instruction not interpretable yet!");
GenericValue callExternalFunction(Function *F,
ArrayRef<GenericValue> ArgVals);
void exitCalled(GenericValue GV);
void addAtExitHandler(Function *F) {
GenericValue *getFirstVarArg () {
return &(ECStack.back ().VarArgs[0]);
private: // Helper functions
GenericValue executeGEPOperation(Value *Ptr, gep_type_iterator I,
gep_type_iterator E, ExecutionContext &SF);
// SwitchToNewBasicBlock - Start execution in a new basic block and run any
// PHI nodes in the top of the block. This is used for intraprocedural
// control flow.
void SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF);
void *getPointerToFunction(Function *F) override { return (void*)F; }
void initializeExecutionEngine() { }
void initializeExternalFunctions();
GenericValue getConstantExprValue(ConstantExpr *CE, ExecutionContext &SF);
GenericValue getOperandValue(Value *V, ExecutionContext &SF);
GenericValue executeTruncInst(Value *SrcVal, Type *DstTy,
ExecutionContext &SF);
GenericValue executeSExtInst(Value *SrcVal, Type *DstTy,
ExecutionContext &SF);
GenericValue executeZExtInst(Value *SrcVal, Type *DstTy,
ExecutionContext &SF);
GenericValue executeFPTruncInst(Value *SrcVal, Type *DstTy,
ExecutionContext &SF);
GenericValue executeFPExtInst(Value *SrcVal, Type *DstTy,
ExecutionContext &SF);
GenericValue executeFPToUIInst(Value *SrcVal, Type *DstTy,
ExecutionContext &SF);
GenericValue executeFPToSIInst(Value *SrcVal, Type *DstTy,
ExecutionContext &SF);
GenericValue executeUIToFPInst(Value *SrcVal, Type *DstTy,
ExecutionContext &SF);
GenericValue executeSIToFPInst(Value *SrcVal, Type *DstTy,
ExecutionContext &SF);
GenericValue executePtrToIntInst(Value *SrcVal, Type *DstTy,
ExecutionContext &SF);
GenericValue executeIntToPtrInst(Value *SrcVal, Type *DstTy,
ExecutionContext &SF);
GenericValue executeBitCastInst(Value *SrcVal, Type *DstTy,
ExecutionContext &SF);
void popStackAndReturnValueToCaller(Type *RetTy, GenericValue Result);
} // End llvm namespace