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      1 //===--- StmtCXX.h - Classes for representing C++ statements ----*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file defines the C++ statement AST node classes.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_CLANG_AST_STMTCXX_H
     15 #define LLVM_CLANG_AST_STMTCXX_H
     16 
     17 #include "clang/AST/DeclarationName.h"
     18 #include "clang/AST/Expr.h"
     19 #include "clang/AST/NestedNameSpecifier.h"
     20 #include "clang/AST/Stmt.h"
     21 #include "llvm/Support/Compiler.h"
     22 
     23 namespace clang {
     24 
     25 class VarDecl;
     26 
     27 /// CXXCatchStmt - This represents a C++ catch block.
     28 ///
     29 class CXXCatchStmt : public Stmt {
     30   SourceLocation CatchLoc;
     31   /// The exception-declaration of the type.
     32   VarDecl *ExceptionDecl;
     33   /// The handler block.
     34   Stmt *HandlerBlock;
     35 
     36 public:
     37   CXXCatchStmt(SourceLocation catchLoc, VarDecl *exDecl, Stmt *handlerBlock)
     38   : Stmt(CXXCatchStmtClass), CatchLoc(catchLoc), ExceptionDecl(exDecl),
     39     HandlerBlock(handlerBlock) {}
     40 
     41   CXXCatchStmt(EmptyShell Empty)
     42   : Stmt(CXXCatchStmtClass), ExceptionDecl(nullptr), HandlerBlock(nullptr) {}
     43 
     44   SourceLocation getLocStart() const LLVM_READONLY { return CatchLoc; }
     45   SourceLocation getLocEnd() const LLVM_READONLY {
     46     return HandlerBlock->getLocEnd();
     47   }
     48 
     49   SourceLocation getCatchLoc() const { return CatchLoc; }
     50   VarDecl *getExceptionDecl() const { return ExceptionDecl; }
     51   QualType getCaughtType() const;
     52   Stmt *getHandlerBlock() const { return HandlerBlock; }
     53 
     54   static bool classof(const Stmt *T) {
     55     return T->getStmtClass() == CXXCatchStmtClass;
     56   }
     57 
     58   child_range children() { return child_range(&HandlerBlock, &HandlerBlock+1); }
     59 
     60   friend class ASTStmtReader;
     61 };
     62 
     63 /// CXXTryStmt - A C++ try block, including all handlers.
     64 ///
     65 class CXXTryStmt : public Stmt {
     66   SourceLocation TryLoc;
     67   unsigned NumHandlers;
     68 
     69   CXXTryStmt(SourceLocation tryLoc, Stmt *tryBlock, ArrayRef<Stmt*> handlers);
     70 
     71   CXXTryStmt(EmptyShell Empty, unsigned numHandlers)
     72     : Stmt(CXXTryStmtClass), NumHandlers(numHandlers) { }
     73 
     74   Stmt const * const *getStmts() const {
     75     return reinterpret_cast<Stmt const * const*>(this + 1);
     76   }
     77   Stmt **getStmts() {
     78     return reinterpret_cast<Stmt **>(this + 1);
     79   }
     80 
     81 public:
     82   static CXXTryStmt *Create(const ASTContext &C, SourceLocation tryLoc,
     83                             Stmt *tryBlock, ArrayRef<Stmt*> handlers);
     84 
     85   static CXXTryStmt *Create(const ASTContext &C, EmptyShell Empty,
     86                             unsigned numHandlers);
     87 
     88   SourceLocation getLocStart() const LLVM_READONLY { return getTryLoc(); }
     89   SourceLocation getLocEnd() const LLVM_READONLY { return getEndLoc(); }
     90 
     91   SourceLocation getTryLoc() const { return TryLoc; }
     92   SourceLocation getEndLoc() const {
     93     return getStmts()[NumHandlers]->getLocEnd();
     94   }
     95 
     96   CompoundStmt *getTryBlock() {
     97     return cast<CompoundStmt>(getStmts()[0]);
     98   }
     99   const CompoundStmt *getTryBlock() const {
    100     return cast<CompoundStmt>(getStmts()[0]);
    101   }
    102 
    103   unsigned getNumHandlers() const { return NumHandlers; }
    104   CXXCatchStmt *getHandler(unsigned i) {
    105     return cast<CXXCatchStmt>(getStmts()[i + 1]);
    106   }
    107   const CXXCatchStmt *getHandler(unsigned i) const {
    108     return cast<CXXCatchStmt>(getStmts()[i + 1]);
    109   }
    110 
    111   static bool classof(const Stmt *T) {
    112     return T->getStmtClass() == CXXTryStmtClass;
    113   }
    114 
    115   child_range children() {
    116     return child_range(getStmts(), getStmts() + getNumHandlers() + 1);
    117   }
    118 
    119   friend class ASTStmtReader;
    120 };
    121 
    122 /// CXXForRangeStmt - This represents C++0x [stmt.ranged]'s ranged for
    123 /// statement, represented as 'for (range-declarator : range-expression)'.
    124 ///
    125 /// This is stored in a partially-desugared form to allow full semantic
    126 /// analysis of the constituent components. The original syntactic components
    127 /// can be extracted using getLoopVariable and getRangeInit.
    128 class CXXForRangeStmt : public Stmt {
    129   SourceLocation ForLoc;
    130   enum { RANGE, BEGINSTMT, ENDSTMT, COND, INC, LOOPVAR, BODY, END };
    131   // SubExprs[RANGE] is an expression or declstmt.
    132   // SubExprs[COND] and SubExprs[INC] are expressions.
    133   Stmt *SubExprs[END];
    134   SourceLocation CoawaitLoc;
    135   SourceLocation ColonLoc;
    136   SourceLocation RParenLoc;
    137 
    138   friend class ASTStmtReader;
    139 public:
    140   CXXForRangeStmt(DeclStmt *Range, DeclStmt *Begin, DeclStmt *End,
    141                   Expr *Cond, Expr *Inc, DeclStmt *LoopVar, Stmt *Body,
    142                   SourceLocation FL, SourceLocation CAL, SourceLocation CL,
    143                   SourceLocation RPL);
    144   CXXForRangeStmt(EmptyShell Empty) : Stmt(CXXForRangeStmtClass, Empty) { }
    145 
    146 
    147   VarDecl *getLoopVariable();
    148   Expr *getRangeInit();
    149 
    150   const VarDecl *getLoopVariable() const;
    151   const Expr *getRangeInit() const;
    152 
    153 
    154   DeclStmt *getRangeStmt() { return cast<DeclStmt>(SubExprs[RANGE]); }
    155   DeclStmt *getBeginStmt() {
    156     return cast_or_null<DeclStmt>(SubExprs[BEGINSTMT]);
    157   }
    158   DeclStmt *getEndStmt() { return cast_or_null<DeclStmt>(SubExprs[ENDSTMT]); }
    159   Expr *getCond() { return cast_or_null<Expr>(SubExprs[COND]); }
    160   Expr *getInc() { return cast_or_null<Expr>(SubExprs[INC]); }
    161   DeclStmt *getLoopVarStmt() { return cast<DeclStmt>(SubExprs[LOOPVAR]); }
    162   Stmt *getBody() { return SubExprs[BODY]; }
    163 
    164   const DeclStmt *getRangeStmt() const {
    165     return cast<DeclStmt>(SubExprs[RANGE]);
    166   }
    167   const DeclStmt *getBeginStmt() const {
    168     return cast_or_null<DeclStmt>(SubExprs[BEGINSTMT]);
    169   }
    170   const DeclStmt *getEndStmt() const {
    171     return cast_or_null<DeclStmt>(SubExprs[ENDSTMT]);
    172   }
    173   const Expr *getCond() const {
    174     return cast_or_null<Expr>(SubExprs[COND]);
    175   }
    176   const Expr *getInc() const {
    177     return cast_or_null<Expr>(SubExprs[INC]);
    178   }
    179   const DeclStmt *getLoopVarStmt() const {
    180     return cast<DeclStmt>(SubExprs[LOOPVAR]);
    181   }
    182   const Stmt *getBody() const { return SubExprs[BODY]; }
    183 
    184   void setRangeInit(Expr *E) { SubExprs[RANGE] = reinterpret_cast<Stmt*>(E); }
    185   void setRangeStmt(Stmt *S) { SubExprs[RANGE] = S; }
    186   void setBeginStmt(Stmt *S) { SubExprs[BEGINSTMT] = S; }
    187   void setEndStmt(Stmt *S) { SubExprs[ENDSTMT] = S; }
    188   void setCond(Expr *E) { SubExprs[COND] = reinterpret_cast<Stmt*>(E); }
    189   void setInc(Expr *E) { SubExprs[INC] = reinterpret_cast<Stmt*>(E); }
    190   void setLoopVarStmt(Stmt *S) { SubExprs[LOOPVAR] = S; }
    191   void setBody(Stmt *S) { SubExprs[BODY] = S; }
    192 
    193   SourceLocation getForLoc() const { return ForLoc; }
    194   SourceLocation getCoawaitLoc() const { return CoawaitLoc; }
    195   SourceLocation getColonLoc() const { return ColonLoc; }
    196   SourceLocation getRParenLoc() const { return RParenLoc; }
    197 
    198   SourceLocation getLocStart() const LLVM_READONLY { return ForLoc; }
    199   SourceLocation getLocEnd() const LLVM_READONLY {
    200     return SubExprs[BODY]->getLocEnd();
    201   }
    202 
    203   static bool classof(const Stmt *T) {
    204     return T->getStmtClass() == CXXForRangeStmtClass;
    205   }
    206 
    207   // Iterators
    208   child_range children() {
    209     return child_range(&SubExprs[0], &SubExprs[END]);
    210   }
    211 };
    212 
    213 /// \brief Representation of a Microsoft __if_exists or __if_not_exists
    214 /// statement with a dependent name.
    215 ///
    216 /// The __if_exists statement can be used to include a sequence of statements
    217 /// in the program only when a particular dependent name does not exist. For
    218 /// example:
    219 ///
    220 /// \code
    221 /// template<typename T>
    222 /// void call_foo(T &t) {
    223 ///   __if_exists (T::foo) {
    224 ///     t.foo(); // okay: only called when T::foo exists.
    225 ///   }
    226 /// }
    227 /// \endcode
    228 ///
    229 /// Similarly, the __if_not_exists statement can be used to include the
    230 /// statements when a particular name does not exist.
    231 ///
    232 /// Note that this statement only captures __if_exists and __if_not_exists
    233 /// statements whose name is dependent. All non-dependent cases are handled
    234 /// directly in the parser, so that they don't introduce a new scope. Clang
    235 /// introduces scopes in the dependent case to keep names inside the compound
    236 /// statement from leaking out into the surround statements, which would
    237 /// compromise the template instantiation model. This behavior differs from
    238 /// Visual C++ (which never introduces a scope), but is a fairly reasonable
    239 /// approximation of the VC++ behavior.
    240 class MSDependentExistsStmt : public Stmt {
    241   SourceLocation KeywordLoc;
    242   bool IsIfExists;
    243   NestedNameSpecifierLoc QualifierLoc;
    244   DeclarationNameInfo NameInfo;
    245   Stmt *SubStmt;
    246 
    247   friend class ASTReader;
    248   friend class ASTStmtReader;
    249 
    250 public:
    251   MSDependentExistsStmt(SourceLocation KeywordLoc, bool IsIfExists,
    252                         NestedNameSpecifierLoc QualifierLoc,
    253                         DeclarationNameInfo NameInfo,
    254                         CompoundStmt *SubStmt)
    255   : Stmt(MSDependentExistsStmtClass),
    256     KeywordLoc(KeywordLoc), IsIfExists(IsIfExists),
    257     QualifierLoc(QualifierLoc), NameInfo(NameInfo),
    258     SubStmt(reinterpret_cast<Stmt *>(SubStmt)) { }
    259 
    260   /// \brief Retrieve the location of the __if_exists or __if_not_exists
    261   /// keyword.
    262   SourceLocation getKeywordLoc() const { return KeywordLoc; }
    263 
    264   /// \brief Determine whether this is an __if_exists statement.
    265   bool isIfExists() const { return IsIfExists; }
    266 
    267   /// \brief Determine whether this is an __if_exists statement.
    268   bool isIfNotExists() const { return !IsIfExists; }
    269 
    270   /// \brief Retrieve the nested-name-specifier that qualifies this name, if
    271   /// any.
    272   NestedNameSpecifierLoc getQualifierLoc() const { return QualifierLoc; }
    273 
    274   /// \brief Retrieve the name of the entity we're testing for, along with
    275   /// location information
    276   DeclarationNameInfo getNameInfo() const { return NameInfo; }
    277 
    278   /// \brief Retrieve the compound statement that will be included in the
    279   /// program only if the existence of the symbol matches the initial keyword.
    280   CompoundStmt *getSubStmt() const {
    281     return reinterpret_cast<CompoundStmt *>(SubStmt);
    282   }
    283 
    284   SourceLocation getLocStart() const LLVM_READONLY { return KeywordLoc; }
    285   SourceLocation getLocEnd() const LLVM_READONLY { return SubStmt->getLocEnd();}
    286 
    287   child_range children() {
    288     return child_range(&SubStmt, &SubStmt+1);
    289   }
    290 
    291   static bool classof(const Stmt *T) {
    292     return T->getStmtClass() == MSDependentExistsStmtClass;
    293   }
    294 };
    295 
    296 /// \brief Represents the body of a coroutine. This wraps the normal function
    297 /// body and holds the additional semantic context required to set up and tear
    298 /// down the coroutine frame.
    299 class CoroutineBodyStmt : public Stmt {
    300   enum SubStmt {
    301     Body,          ///< The body of the coroutine.
    302     Promise,       ///< The promise statement.
    303     InitSuspend,   ///< The initial suspend statement, run before the body.
    304     FinalSuspend,  ///< The final suspend statement, run after the body.
    305     OnException,   ///< Handler for exceptions thrown in the body.
    306     OnFallthrough, ///< Handler for control flow falling off the body.
    307     ReturnValue,   ///< Return value for thunk function.
    308     FirstParamMove ///< First offset for move construction of parameter copies.
    309   };
    310   Stmt *SubStmts[SubStmt::FirstParamMove];
    311 
    312   friend class ASTStmtReader;
    313 public:
    314   CoroutineBodyStmt(Stmt *Body, Stmt *Promise, Stmt *InitSuspend,
    315                     Stmt *FinalSuspend, Stmt *OnException, Stmt *OnFallthrough,
    316                     Expr *ReturnValue, ArrayRef<Expr *> ParamMoves)
    317       : Stmt(CoroutineBodyStmtClass) {
    318     SubStmts[CoroutineBodyStmt::Body] = Body;
    319     SubStmts[CoroutineBodyStmt::Promise] = Promise;
    320     SubStmts[CoroutineBodyStmt::InitSuspend] = InitSuspend;
    321     SubStmts[CoroutineBodyStmt::FinalSuspend] = FinalSuspend;
    322     SubStmts[CoroutineBodyStmt::OnException] = OnException;
    323     SubStmts[CoroutineBodyStmt::OnFallthrough] = OnFallthrough;
    324     SubStmts[CoroutineBodyStmt::ReturnValue] = ReturnValue;
    325     // FIXME: Tail-allocate space for parameter move expressions and store them.
    326     assert(ParamMoves.empty() && "not implemented yet");
    327   }
    328 
    329   /// \brief Retrieve the body of the coroutine as written. This will be either
    330   /// a CompoundStmt or a TryStmt.
    331   Stmt *getBody() const {
    332     return SubStmts[SubStmt::Body];
    333   }
    334 
    335   Stmt *getPromiseDeclStmt() const { return SubStmts[SubStmt::Promise]; }
    336   VarDecl *getPromiseDecl() const {
    337     return cast<VarDecl>(cast<DeclStmt>(getPromiseDeclStmt())->getSingleDecl());
    338   }
    339 
    340   Stmt *getInitSuspendStmt() const { return SubStmts[SubStmt::InitSuspend]; }
    341   Stmt *getFinalSuspendStmt() const { return SubStmts[SubStmt::FinalSuspend]; }
    342 
    343   Stmt *getExceptionHandler() const { return SubStmts[SubStmt::OnException]; }
    344   Stmt *getFallthroughHandler() const {
    345     return SubStmts[SubStmt::OnFallthrough];
    346   }
    347 
    348   Expr *getReturnValueInit() const {
    349     return cast<Expr>(SubStmts[SubStmt::ReturnValue]);
    350   }
    351 
    352   SourceLocation getLocStart() const LLVM_READONLY {
    353     return getBody()->getLocStart();
    354   }
    355   SourceLocation getLocEnd() const LLVM_READONLY {
    356     return getBody()->getLocEnd();
    357   }
    358 
    359   child_range children() {
    360     return child_range(SubStmts, SubStmts + SubStmt::FirstParamMove);
    361   }
    362 
    363   static bool classof(const Stmt *T) {
    364     return T->getStmtClass() == CoroutineBodyStmtClass;
    365   }
    366 };
    367 
    368 /// \brief Represents a 'co_return' statement in the C++ Coroutines TS.
    369 ///
    370 /// This statament models the initialization of the coroutine promise
    371 /// (encapsulating the eventual notional return value) from an expression
    372 /// (or braced-init-list), followed by termination of the coroutine.
    373 ///
    374 /// This initialization is modeled by the evaluation of the operand
    375 /// followed by a call to one of:
    376 ///   <promise>.return_value(<operand>)
    377 ///   <promise>.return_void()
    378 /// which we name the "promise call".
    379 class CoreturnStmt : public Stmt {
    380   SourceLocation CoreturnLoc;
    381 
    382   enum SubStmt { Operand, PromiseCall, Count };
    383   Stmt *SubStmts[SubStmt::Count];
    384 
    385   friend class ASTStmtReader;
    386 public:
    387   CoreturnStmt(SourceLocation CoreturnLoc, Stmt *Operand, Stmt *PromiseCall)
    388       : Stmt(CoreturnStmtClass), CoreturnLoc(CoreturnLoc) {
    389     SubStmts[SubStmt::Operand] = Operand;
    390     SubStmts[SubStmt::PromiseCall] = PromiseCall;
    391   }
    392 
    393   SourceLocation getKeywordLoc() const { return CoreturnLoc; }
    394 
    395   /// \brief Retrieve the operand of the 'co_return' statement. Will be nullptr
    396   /// if none was specified.
    397   Expr *getOperand() const { return static_cast<Expr*>(SubStmts[Operand]); }
    398 
    399   /// \brief Retrieve the promise call that results from this 'co_return'
    400   /// statement. Will be nullptr if either the coroutine has not yet been
    401   /// finalized or the coroutine has no eventual return type.
    402   Expr *getPromiseCall() const {
    403     return static_cast<Expr*>(SubStmts[PromiseCall]);
    404   }
    405 
    406   SourceLocation getLocStart() const LLVM_READONLY { return CoreturnLoc; }
    407   SourceLocation getLocEnd() const LLVM_READONLY {
    408     return getOperand()->getLocEnd();
    409   }
    410 
    411   child_range children() {
    412     return child_range(SubStmts, SubStmts + SubStmt::Count);
    413   }
    414 
    415   static bool classof(const Stmt *T) {
    416     return T->getStmtClass() == CoreturnStmtClass;
    417   }
    418 };
    419 
    420 }  // end namespace clang
    421 
    422 #endif
    423