| //===--- ByteCodeExprGen.h - Code generator for expressions -----*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Defines the constexpr bytecode compiler. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_CLANG_AST_INTERP_BYTECODEEXPRGEN_H |
| #define LLVM_CLANG_AST_INTERP_BYTECODEEXPRGEN_H |
| |
| #include "ByteCodeEmitter.h" |
| #include "EvalEmitter.h" |
| #include "Pointer.h" |
| #include "PrimType.h" |
| #include "Record.h" |
| #include "clang/AST/Decl.h" |
| #include "clang/AST/Expr.h" |
| #include "clang/AST/StmtVisitor.h" |
| #include "clang/Basic/TargetInfo.h" |
| |
| namespace clang { |
| class QualType; |
| |
| namespace interp { |
| |
| template <class Emitter> class LocalScope; |
| template <class Emitter> class DestructorScope; |
| template <class Emitter> class RecordScope; |
| template <class Emitter> class VariableScope; |
| template <class Emitter> class DeclScope; |
| template <class Emitter> class OptionScope; |
| template <class Emitter> class ArrayIndexScope; |
| |
| /// Compilation context for expressions. |
| template <class Emitter> |
| class ByteCodeExprGen : public ConstStmtVisitor<ByteCodeExprGen<Emitter>, bool>, |
| public Emitter { |
| protected: |
| // Aliases for types defined in the emitter. |
| using LabelTy = typename Emitter::LabelTy; |
| using AddrTy = typename Emitter::AddrTy; |
| |
| /// Current compilation context. |
| Context &Ctx; |
| /// Program to link to. |
| Program &P; |
| |
| public: |
| /// Initializes the compiler and the backend emitter. |
| template <typename... Tys> |
| ByteCodeExprGen(Context &Ctx, Program &P, Tys &&... Args) |
| : Emitter(Ctx, P, Args...), Ctx(Ctx), P(P) {} |
| |
| // Expression visitors - result returned on interp stack. |
| bool VisitCastExpr(const CastExpr *E); |
| bool VisitIntegerLiteral(const IntegerLiteral *E); |
| bool VisitFloatingLiteral(const FloatingLiteral *E); |
| bool VisitParenExpr(const ParenExpr *E); |
| bool VisitBinaryOperator(const BinaryOperator *E); |
| bool VisitLogicalBinOp(const BinaryOperator *E); |
| bool VisitPointerArithBinOp(const BinaryOperator *E); |
| bool VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E); |
| bool VisitCallExpr(const CallExpr *E); |
| bool VisitBuiltinCallExpr(const CallExpr *E); |
| bool VisitCXXMemberCallExpr(const CXXMemberCallExpr *E); |
| bool VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E); |
| bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E); |
| bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E); |
| bool VisitCXXThisExpr(const CXXThisExpr *E); |
| bool VisitUnaryOperator(const UnaryOperator *E); |
| bool VisitDeclRefExpr(const DeclRefExpr *E); |
| bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E); |
| bool VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E); |
| bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E); |
| bool VisitInitListExpr(const InitListExpr *E); |
| bool VisitConstantExpr(const ConstantExpr *E); |
| bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E); |
| bool VisitMemberExpr(const MemberExpr *E); |
| bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *E); |
| bool VisitOpaqueValueExpr(const OpaqueValueExpr *E); |
| bool VisitAbstractConditionalOperator(const AbstractConditionalOperator *E); |
| bool VisitStringLiteral(const StringLiteral *E); |
| bool VisitCharacterLiteral(const CharacterLiteral *E); |
| bool VisitCompoundAssignOperator(const CompoundAssignOperator *E); |
| bool VisitFloatCompoundAssignOperator(const CompoundAssignOperator *E); |
| bool VisitPointerCompoundAssignOperator(const CompoundAssignOperator *E); |
| bool VisitExprWithCleanups(const ExprWithCleanups *E); |
| bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E); |
| bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E); |
| bool VisitTypeTraitExpr(const TypeTraitExpr *E); |
| bool VisitLambdaExpr(const LambdaExpr *E); |
| bool VisitPredefinedExpr(const PredefinedExpr *E); |
| |
| protected: |
| bool visitExpr(const Expr *E) override; |
| bool visitDecl(const VarDecl *VD) override; |
| |
| protected: |
| /// Emits scope cleanup instructions. |
| void emitCleanup(); |
| |
| /// Returns a record type from a record or pointer type. |
| const RecordType *getRecordTy(QualType Ty); |
| |
| /// Returns a record from a record or pointer type. |
| Record *getRecord(QualType Ty); |
| Record *getRecord(const RecordDecl *RD); |
| |
| // Returns a function for the given FunctionDecl. |
| // If the function does not exist yet, it is compiled. |
| const Function *getFunction(const FunctionDecl *FD); |
| |
| /// Classifies a type. |
| std::optional<PrimType> classify(const Expr *E) const { |
| return E->isGLValue() ? PT_Ptr : classify(E->getType()); |
| } |
| std::optional<PrimType> classify(QualType Ty) const { |
| return Ctx.classify(Ty); |
| } |
| |
| /// Classifies a known primitive type |
| PrimType classifyPrim(QualType Ty) const { |
| if (auto T = classify(Ty)) { |
| return *T; |
| } |
| llvm_unreachable("not a primitive type"); |
| } |
| |
| /// Evaluates an expression for side effects and discards the result. |
| bool discard(const Expr *E); |
| /// Evaluates an expression and places result on stack. |
| bool visit(const Expr *E); |
| /// Compiles an initializer. |
| bool visitInitializer(const Expr *E); |
| /// Compiles an array initializer. |
| bool visitArrayInitializer(const Expr *Initializer); |
| /// Compiles a record initializer. |
| bool visitRecordInitializer(const Expr *Initializer); |
| /// Creates and initializes a variable from the given decl. |
| bool visitVarDecl(const VarDecl *VD); |
| |
| /// Visits an expression and converts it to a boolean. |
| bool visitBool(const Expr *E); |
| |
| /// Visits an initializer for a local. |
| bool visitLocalInitializer(const Expr *Init, unsigned I) { |
| if (!this->emitGetPtrLocal(I, Init)) |
| return false; |
| |
| if (!visitInitializer(Init)) |
| return false; |
| |
| return this->emitPopPtr(Init); |
| } |
| |
| /// Visits an initializer for a global. |
| bool visitGlobalInitializer(const Expr *Init, unsigned I) { |
| if (!this->emitGetPtrGlobal(I, Init)) |
| return false; |
| |
| if (!visitInitializer(Init)) |
| return false; |
| |
| if ((Init->getType()->isArrayType() || Init->getType()->isRecordType()) && |
| !this->emitCheckGlobalCtor(Init)) |
| return false; |
| |
| return this->emitPopPtr(Init); |
| } |
| |
| /// Visits a delegated initializer. |
| bool visitThisInitializer(const Expr *I) { |
| if (!this->emitThis(I)) |
| return false; |
| |
| if (!visitInitializer(I)) |
| return false; |
| |
| return this->emitPopPtr(I); |
| } |
| |
| bool visitConditional(const AbstractConditionalOperator *E, |
| llvm::function_ref<bool(const Expr *)> V); |
| |
| /// Creates a local primitive value. |
| unsigned allocateLocalPrimitive(DeclTy &&Decl, PrimType Ty, bool IsConst, |
| bool IsExtended = false); |
| |
| /// Allocates a space storing a local given its type. |
| std::optional<unsigned> allocateLocal(DeclTy &&Decl, bool IsExtended = false); |
| |
| private: |
| friend class VariableScope<Emitter>; |
| friend class LocalScope<Emitter>; |
| friend class DestructorScope<Emitter>; |
| friend class RecordScope<Emitter>; |
| friend class DeclScope<Emitter>; |
| friend class OptionScope<Emitter>; |
| friend class ArrayIndexScope<Emitter>; |
| |
| /// Emits a zero initializer. |
| bool visitZeroInitializer(QualType QT, const Expr *E); |
| |
| enum class DerefKind { |
| /// Value is read and pushed to stack. |
| Read, |
| /// Direct method generates a value which is written. Returns pointer. |
| Write, |
| /// Direct method receives the value, pushes mutated value. Returns pointer. |
| ReadWrite, |
| }; |
| |
| /// Method to directly load a value. If the value can be fetched directly, |
| /// the direct handler is called. Otherwise, a pointer is left on the stack |
| /// and the indirect handler is expected to operate on that. |
| bool dereference(const Expr *LV, DerefKind AK, |
| llvm::function_ref<bool(PrimType)> Direct, |
| llvm::function_ref<bool(PrimType)> Indirect); |
| bool dereferenceParam(const Expr *LV, PrimType T, const ParmVarDecl *PD, |
| DerefKind AK, |
| llvm::function_ref<bool(PrimType)> Direct, |
| llvm::function_ref<bool(PrimType)> Indirect); |
| bool dereferenceVar(const Expr *LV, PrimType T, const VarDecl *PD, |
| DerefKind AK, llvm::function_ref<bool(PrimType)> Direct, |
| llvm::function_ref<bool(PrimType)> Indirect); |
| |
| /// Emits an APSInt constant. |
| bool emitConst(const llvm::APSInt &Value, const Expr *E); |
| bool emitConst(const llvm::APInt &Value, const Expr *E) { |
| return emitConst(static_cast<llvm::APSInt>(Value), E); |
| } |
| |
| /// Emits an integer constant. |
| template <typename T> bool emitConst(T Value, const Expr *E); |
| |
| /// Returns the CXXRecordDecl for the type of the given expression, |
| /// or nullptr if no such decl exists. |
| const CXXRecordDecl *getRecordDecl(const Expr *E) const { |
| QualType T = E->getType(); |
| if (const auto *RD = T->getPointeeCXXRecordDecl()) |
| return RD; |
| return T->getAsCXXRecordDecl(); |
| } |
| |
| llvm::RoundingMode getRoundingMode(const Expr *E) const { |
| FPOptions FPO = E->getFPFeaturesInEffect(Ctx.getLangOpts()); |
| |
| if (FPO.getRoundingMode() == llvm::RoundingMode::Dynamic) |
| return llvm::RoundingMode::NearestTiesToEven; |
| |
| return FPO.getRoundingMode(); |
| } |
| |
| bool emitRecordDestruction(const Descriptor *Desc); |
| bool emitDerivedToBaseCasts(const RecordType *DerivedType, |
| const RecordType *BaseType, const Expr *E); |
| |
| protected: |
| /// Variable to storage mapping. |
| llvm::DenseMap<const ValueDecl *, Scope::Local> Locals; |
| |
| /// OpaqueValueExpr to location mapping. |
| llvm::DenseMap<const OpaqueValueExpr *, unsigned> OpaqueExprs; |
| |
| /// Current scope. |
| VariableScope<Emitter> *VarScope = nullptr; |
| |
| /// Current argument index. Needed to emit ArrayInitIndexExpr. |
| std::optional<uint64_t> ArrayIndex; |
| |
| /// Flag indicating if return value is to be discarded. |
| bool DiscardResult = false; |
| }; |
| |
| extern template class ByteCodeExprGen<ByteCodeEmitter>; |
| extern template class ByteCodeExprGen<EvalEmitter>; |
| |
| /// Scope chain managing the variable lifetimes. |
| template <class Emitter> class VariableScope { |
| public: |
| VariableScope(ByteCodeExprGen<Emitter> *Ctx) |
| : Ctx(Ctx), Parent(Ctx->VarScope) { |
| Ctx->VarScope = this; |
| } |
| |
| virtual ~VariableScope() { Ctx->VarScope = this->Parent; } |
| |
| void add(const Scope::Local &Local, bool IsExtended) { |
| if (IsExtended) |
| this->addExtended(Local); |
| else |
| this->addLocal(Local); |
| } |
| |
| virtual void addLocal(const Scope::Local &Local) { |
| if (this->Parent) |
| this->Parent->addLocal(Local); |
| } |
| |
| virtual void addExtended(const Scope::Local &Local) { |
| if (this->Parent) |
| this->Parent->addExtended(Local); |
| } |
| |
| virtual void emitDestruction() {} |
| virtual void emitDestructors() {} |
| VariableScope *getParent() const { return Parent; } |
| |
| protected: |
| /// ByteCodeExprGen instance. |
| ByteCodeExprGen<Emitter> *Ctx; |
| /// Link to the parent scope. |
| VariableScope *Parent; |
| }; |
| |
| /// Generic scope for local variables. |
| template <class Emitter> class LocalScope : public VariableScope<Emitter> { |
| public: |
| LocalScope(ByteCodeExprGen<Emitter> *Ctx) : VariableScope<Emitter>(Ctx) {} |
| |
| /// Emit a Destroy op for this scope. |
| ~LocalScope() override { |
| if (!Idx) |
| return; |
| this->Ctx->emitDestroy(*Idx, SourceInfo{}); |
| } |
| |
| /// Overriden to support explicit destruction. |
| void emitDestruction() override { |
| if (!Idx) |
| return; |
| this->emitDestructors(); |
| this->Ctx->emitDestroy(*Idx, SourceInfo{}); |
| this->Idx = std::nullopt; |
| } |
| |
| void addLocal(const Scope::Local &Local) override { |
| if (!Idx) { |
| Idx = this->Ctx->Descriptors.size(); |
| this->Ctx->Descriptors.emplace_back(); |
| } |
| |
| this->Ctx->Descriptors[*Idx].emplace_back(Local); |
| } |
| |
| void emitDestructors() override { |
| if (!Idx) |
| return; |
| // Emit destructor calls for local variables of record |
| // type with a destructor. |
| for (Scope::Local &Local : this->Ctx->Descriptors[*Idx]) { |
| if (!Local.Desc->isPrimitive() && !Local.Desc->isPrimitiveArray()) { |
| this->Ctx->emitGetPtrLocal(Local.Offset, SourceInfo{}); |
| this->Ctx->emitRecordDestruction(Local.Desc); |
| } |
| } |
| } |
| |
| /// Index of the scope in the chain. |
| std::optional<unsigned> Idx; |
| }; |
| |
| /// Emits the destructors of the variables of \param OtherScope |
| /// when this scope is destroyed. Does not create a Scope in the bytecode at |
| /// all, this is just a RAII object to emit destructors. |
| template <class Emitter> class DestructorScope final { |
| public: |
| DestructorScope(LocalScope<Emitter> &OtherScope) : OtherScope(OtherScope) {} |
| |
| ~DestructorScope() { OtherScope.emitDestructors(); } |
| |
| private: |
| LocalScope<Emitter> &OtherScope; |
| }; |
| |
| /// Like a regular LocalScope, except that the destructors of all local |
| /// variables are automatically emitted when the AutoScope is destroyed. |
| template <class Emitter> class AutoScope : public LocalScope<Emitter> { |
| public: |
| AutoScope(ByteCodeExprGen<Emitter> *Ctx) |
| : LocalScope<Emitter>(Ctx), DS(*this) {} |
| |
| private: |
| DestructorScope<Emitter> DS; |
| }; |
| |
| /// Scope for storage declared in a compound statement. |
| template <class Emitter> class BlockScope final : public AutoScope<Emitter> { |
| public: |
| BlockScope(ByteCodeExprGen<Emitter> *Ctx) : AutoScope<Emitter>(Ctx) {} |
| |
| void addExtended(const Scope::Local &Local) override { |
| // If we to this point, just add the variable as a normal local |
| // variable. It will be destroyed at the end of the block just |
| // like all others. |
| this->addLocal(Local); |
| } |
| }; |
| |
| /// Expression scope which tracks potentially lifetime extended |
| /// temporaries which are hoisted to the parent scope on exit. |
| template <class Emitter> class ExprScope final : public AutoScope<Emitter> { |
| public: |
| ExprScope(ByteCodeExprGen<Emitter> *Ctx) : AutoScope<Emitter>(Ctx) {} |
| |
| void addExtended(const Scope::Local &Local) override { |
| if (this->Parent) |
| this->Parent->addLocal(Local); |
| } |
| }; |
| |
| template <class Emitter> class ArrayIndexScope final { |
| public: |
| ArrayIndexScope(ByteCodeExprGen<Emitter> *Ctx, uint64_t Index) : Ctx(Ctx) { |
| OldArrayIndex = Ctx->ArrayIndex; |
| Ctx->ArrayIndex = Index; |
| } |
| |
| ~ArrayIndexScope() { Ctx->ArrayIndex = OldArrayIndex; } |
| |
| private: |
| ByteCodeExprGen<Emitter> *Ctx; |
| std::optional<uint64_t> OldArrayIndex; |
| }; |
| |
| } // namespace interp |
| } // namespace clang |
| |
| #endif |