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      1 //===- StmtVisitor.h - Visitor for Stmt subclasses --------------*- 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 file defines the StmtVisitor and ConstStmtVisitor interfaces.
     10 //
     11 //===----------------------------------------------------------------------===//
     12 
     13 #ifndef LLVM_CLANG_AST_STMTVISITOR_H
     14 #define LLVM_CLANG_AST_STMTVISITOR_H
     15 
     16 #include "clang/AST/ExprConcepts.h"
     17 #include "clang/AST/ExprCXX.h"
     18 #include "clang/AST/ExprObjC.h"
     19 #include "clang/AST/ExprOpenMP.h"
     20 #include "clang/AST/Stmt.h"
     21 #include "clang/AST/StmtCXX.h"
     22 #include "clang/AST/StmtObjC.h"
     23 #include "clang/AST/StmtOpenMP.h"
     24 #include "clang/Basic/LLVM.h"
     25 #include "llvm/ADT/STLExtras.h"
     26 #include "llvm/Support/Casting.h"
     27 #include "llvm/Support/ErrorHandling.h"
     28 #include <utility>
     29 
     30 namespace clang {
     31 /// StmtVisitorBase - This class implements a simple visitor for Stmt
     32 /// subclasses. Since Expr derives from Stmt, this also includes support for
     33 /// visiting Exprs.
     34 template<template <typename> class Ptr, typename ImplClass, typename RetTy=void,
     35          class... ParamTys>
     36 class StmtVisitorBase {
     37 public:
     38 #define PTR(CLASS) typename Ptr<CLASS>::type
     39 #define DISPATCH(NAME, CLASS) \
     40   return static_cast<ImplClass*>(this)->Visit ## NAME( \
     41     static_cast<PTR(CLASS)>(S), std::forward<ParamTys>(P)...)
     42 
     43   RetTy Visit(PTR(Stmt) S, ParamTys... P) {
     44     // If we have a binary expr, dispatch to the subcode of the binop.  A smart
     45     // optimizer (e.g. LLVM) will fold this comparison into the switch stmt
     46     // below.
     47     if (PTR(BinaryOperator) BinOp = dyn_cast<BinaryOperator>(S)) {
     48       switch (BinOp->getOpcode()) {
     49       case BO_PtrMemD:   DISPATCH(BinPtrMemD,   BinaryOperator);
     50       case BO_PtrMemI:   DISPATCH(BinPtrMemI,   BinaryOperator);
     51       case BO_Mul:       DISPATCH(BinMul,       BinaryOperator);
     52       case BO_Div:       DISPATCH(BinDiv,       BinaryOperator);
     53       case BO_Rem:       DISPATCH(BinRem,       BinaryOperator);
     54       case BO_Add:       DISPATCH(BinAdd,       BinaryOperator);
     55       case BO_Sub:       DISPATCH(BinSub,       BinaryOperator);
     56       case BO_Shl:       DISPATCH(BinShl,       BinaryOperator);
     57       case BO_Shr:       DISPATCH(BinShr,       BinaryOperator);
     58 
     59       case BO_LT:        DISPATCH(BinLT,        BinaryOperator);
     60       case BO_GT:        DISPATCH(BinGT,        BinaryOperator);
     61       case BO_LE:        DISPATCH(BinLE,        BinaryOperator);
     62       case BO_GE:        DISPATCH(BinGE,        BinaryOperator);
     63       case BO_EQ:        DISPATCH(BinEQ,        BinaryOperator);
     64       case BO_NE:        DISPATCH(BinNE,        BinaryOperator);
     65       case BO_Cmp:       DISPATCH(BinCmp,       BinaryOperator);
     66 
     67       case BO_And:       DISPATCH(BinAnd,       BinaryOperator);
     68       case BO_Xor:       DISPATCH(BinXor,       BinaryOperator);
     69       case BO_Or :       DISPATCH(BinOr,        BinaryOperator);
     70       case BO_LAnd:      DISPATCH(BinLAnd,      BinaryOperator);
     71       case BO_LOr :      DISPATCH(BinLOr,       BinaryOperator);
     72       case BO_Assign:    DISPATCH(BinAssign,    BinaryOperator);
     73       case BO_MulAssign: DISPATCH(BinMulAssign, CompoundAssignOperator);
     74       case BO_DivAssign: DISPATCH(BinDivAssign, CompoundAssignOperator);
     75       case BO_RemAssign: DISPATCH(BinRemAssign, CompoundAssignOperator);
     76       case BO_AddAssign: DISPATCH(BinAddAssign, CompoundAssignOperator);
     77       case BO_SubAssign: DISPATCH(BinSubAssign, CompoundAssignOperator);
     78       case BO_ShlAssign: DISPATCH(BinShlAssign, CompoundAssignOperator);
     79       case BO_ShrAssign: DISPATCH(BinShrAssign, CompoundAssignOperator);
     80       case BO_AndAssign: DISPATCH(BinAndAssign, CompoundAssignOperator);
     81       case BO_OrAssign:  DISPATCH(BinOrAssign,  CompoundAssignOperator);
     82       case BO_XorAssign: DISPATCH(BinXorAssign, CompoundAssignOperator);
     83       case BO_Comma:     DISPATCH(BinComma,     BinaryOperator);
     84       }
     85     } else if (PTR(UnaryOperator) UnOp = dyn_cast<UnaryOperator>(S)) {
     86       switch (UnOp->getOpcode()) {
     87       case UO_PostInc:   DISPATCH(UnaryPostInc,   UnaryOperator);
     88       case UO_PostDec:   DISPATCH(UnaryPostDec,   UnaryOperator);
     89       case UO_PreInc:    DISPATCH(UnaryPreInc,    UnaryOperator);
     90       case UO_PreDec:    DISPATCH(UnaryPreDec,    UnaryOperator);
     91       case UO_AddrOf:    DISPATCH(UnaryAddrOf,    UnaryOperator);
     92       case UO_Deref:     DISPATCH(UnaryDeref,     UnaryOperator);
     93       case UO_Plus:      DISPATCH(UnaryPlus,      UnaryOperator);
     94       case UO_Minus:     DISPATCH(UnaryMinus,     UnaryOperator);
     95       case UO_Not:       DISPATCH(UnaryNot,       UnaryOperator);
     96       case UO_LNot:      DISPATCH(UnaryLNot,      UnaryOperator);
     97       case UO_Real:      DISPATCH(UnaryReal,      UnaryOperator);
     98       case UO_Imag:      DISPATCH(UnaryImag,      UnaryOperator);
     99       case UO_Extension: DISPATCH(UnaryExtension, UnaryOperator);
    100       case UO_Coawait:   DISPATCH(UnaryCoawait,   UnaryOperator);
    101       }
    102     }
    103 
    104     // Top switch stmt: dispatch to VisitFooStmt for each FooStmt.
    105     switch (S->getStmtClass()) {
    106     default: llvm_unreachable("Unknown stmt kind!");
    107 #define ABSTRACT_STMT(STMT)
    108 #define STMT(CLASS, PARENT)                              \
    109     case Stmt::CLASS ## Class: DISPATCH(CLASS, CLASS);
    110 #include "clang/AST/StmtNodes.inc"
    111     }
    112   }
    113 
    114   // If the implementation chooses not to implement a certain visit method, fall
    115   // back on VisitExpr or whatever else is the superclass.
    116 #define STMT(CLASS, PARENT)                                   \
    117   RetTy Visit ## CLASS(PTR(CLASS) S, ParamTys... P) { DISPATCH(PARENT, PARENT); }
    118 #include "clang/AST/StmtNodes.inc"
    119 
    120   // If the implementation doesn't implement binary operator methods, fall back
    121   // on VisitBinaryOperator.
    122 #define BINOP_FALLBACK(NAME) \
    123   RetTy VisitBin ## NAME(PTR(BinaryOperator) S, ParamTys... P) { \
    124     DISPATCH(BinaryOperator, BinaryOperator); \
    125   }
    126   BINOP_FALLBACK(PtrMemD)                    BINOP_FALLBACK(PtrMemI)
    127   BINOP_FALLBACK(Mul)   BINOP_FALLBACK(Div)  BINOP_FALLBACK(Rem)
    128   BINOP_FALLBACK(Add)   BINOP_FALLBACK(Sub)  BINOP_FALLBACK(Shl)
    129   BINOP_FALLBACK(Shr)
    130 
    131   BINOP_FALLBACK(LT)    BINOP_FALLBACK(GT)   BINOP_FALLBACK(LE)
    132   BINOP_FALLBACK(GE)    BINOP_FALLBACK(EQ)   BINOP_FALLBACK(NE)
    133   BINOP_FALLBACK(Cmp)
    134 
    135   BINOP_FALLBACK(And)   BINOP_FALLBACK(Xor)  BINOP_FALLBACK(Or)
    136   BINOP_FALLBACK(LAnd)  BINOP_FALLBACK(LOr)
    137 
    138   BINOP_FALLBACK(Assign)
    139   BINOP_FALLBACK(Comma)
    140 #undef BINOP_FALLBACK
    141 
    142   // If the implementation doesn't implement compound assignment operator
    143   // methods, fall back on VisitCompoundAssignOperator.
    144 #define CAO_FALLBACK(NAME) \
    145   RetTy VisitBin ## NAME(PTR(CompoundAssignOperator) S, ParamTys... P) { \
    146     DISPATCH(CompoundAssignOperator, CompoundAssignOperator); \
    147   }
    148   CAO_FALLBACK(MulAssign) CAO_FALLBACK(DivAssign) CAO_FALLBACK(RemAssign)
    149   CAO_FALLBACK(AddAssign) CAO_FALLBACK(SubAssign) CAO_FALLBACK(ShlAssign)
    150   CAO_FALLBACK(ShrAssign) CAO_FALLBACK(AndAssign) CAO_FALLBACK(OrAssign)
    151   CAO_FALLBACK(XorAssign)
    152 #undef CAO_FALLBACK
    153 
    154   // If the implementation doesn't implement unary operator methods, fall back
    155   // on VisitUnaryOperator.
    156 #define UNARYOP_FALLBACK(NAME) \
    157   RetTy VisitUnary ## NAME(PTR(UnaryOperator) S, ParamTys... P) { \
    158     DISPATCH(UnaryOperator, UnaryOperator);    \
    159   }
    160   UNARYOP_FALLBACK(PostInc)   UNARYOP_FALLBACK(PostDec)
    161   UNARYOP_FALLBACK(PreInc)    UNARYOP_FALLBACK(PreDec)
    162   UNARYOP_FALLBACK(AddrOf)    UNARYOP_FALLBACK(Deref)
    163 
    164   UNARYOP_FALLBACK(Plus)      UNARYOP_FALLBACK(Minus)
    165   UNARYOP_FALLBACK(Not)       UNARYOP_FALLBACK(LNot)
    166   UNARYOP_FALLBACK(Real)      UNARYOP_FALLBACK(Imag)
    167   UNARYOP_FALLBACK(Extension) UNARYOP_FALLBACK(Coawait)
    168 #undef UNARYOP_FALLBACK
    169 
    170   // Base case, ignore it. :)
    171   RetTy VisitStmt(PTR(Stmt) Node, ParamTys... P) { return RetTy(); }
    172 
    173 #undef PTR
    174 #undef DISPATCH
    175 };
    176 
    177 /// StmtVisitor - This class implements a simple visitor for Stmt subclasses.
    178 /// Since Expr derives from Stmt, this also includes support for visiting Exprs.
    179 ///
    180 /// This class does not preserve constness of Stmt pointers (see also
    181 /// ConstStmtVisitor).
    182 template <typename ImplClass, typename RetTy = void, typename... ParamTys>
    183 class StmtVisitor
    184     : public StmtVisitorBase<std::add_pointer, ImplClass, RetTy, ParamTys...> {
    185 };
    186 
    187 /// ConstStmtVisitor - This class implements a simple visitor for Stmt
    188 /// subclasses. Since Expr derives from Stmt, this also includes support for
    189 /// visiting Exprs.
    190 ///
    191 /// This class preserves constness of Stmt pointers (see also StmtVisitor).
    192 template <typename ImplClass, typename RetTy = void, typename... ParamTys>
    193 class ConstStmtVisitor : public StmtVisitorBase<llvm::make_const_ptr, ImplClass,
    194                                                 RetTy, ParamTys...> {};
    195 
    196 } // namespace clang
    197 
    198 #endif // LLVM_CLANG_AST_STMTVISITOR_H
    199