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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, BEGINEND, 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 *BeginEnd,
    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 *getBeginEndStmt() {
    156     return cast_or_null<DeclStmt>(SubExprs[BEGINEND]);
    157   }
    158   Expr *getCond() { return cast_or_null<Expr>(SubExprs[COND]); }
    159   Expr *getInc() { return cast_or_null<Expr>(SubExprs[INC]); }
    160   DeclStmt *getLoopVarStmt() { return cast<DeclStmt>(SubExprs[LOOPVAR]); }
    161   Stmt *getBody() { return SubExprs[BODY]; }
    162 
    163   const DeclStmt *getRangeStmt() const {
    164     return cast<DeclStmt>(SubExprs[RANGE]);
    165   }
    166   const DeclStmt *getBeginEndStmt() const {
    167     return cast_or_null<DeclStmt>(SubExprs[BEGINEND]);
    168   }
    169   const Expr *getCond() const {
    170     return cast_or_null<Expr>(SubExprs[COND]);
    171   }
    172   const Expr *getInc() const {
    173     return cast_or_null<Expr>(SubExprs[INC]);
    174   }
    175   const DeclStmt *getLoopVarStmt() const {
    176     return cast<DeclStmt>(SubExprs[LOOPVAR]);
    177   }
    178   const Stmt *getBody() const { return SubExprs[BODY]; }
    179 
    180   void setRangeInit(Expr *E) { SubExprs[RANGE] = reinterpret_cast<Stmt*>(E); }
    181   void setRangeStmt(Stmt *S) { SubExprs[RANGE] = S; }
    182   void setBeginEndStmt(Stmt *S) { SubExprs[BEGINEND] = S; }
    183   void setCond(Expr *E) { SubExprs[COND] = reinterpret_cast<Stmt*>(E); }
    184   void setInc(Expr *E) { SubExprs[INC] = reinterpret_cast<Stmt*>(E); }
    185   void setLoopVarStmt(Stmt *S) { SubExprs[LOOPVAR] = S; }
    186   void setBody(Stmt *S) { SubExprs[BODY] = S; }
    187 
    188   SourceLocation getForLoc() const { return ForLoc; }
    189   SourceLocation getCoawaitLoc() const { return CoawaitLoc; }
    190   SourceLocation getColonLoc() const { return ColonLoc; }
    191   SourceLocation getRParenLoc() const { return RParenLoc; }
    192 
    193   SourceLocation getLocStart() const LLVM_READONLY { return ForLoc; }
    194   SourceLocation getLocEnd() const LLVM_READONLY {
    195     return SubExprs[BODY]->getLocEnd();
    196   }
    197 
    198   static bool classof(const Stmt *T) {
    199     return T->getStmtClass() == CXXForRangeStmtClass;
    200   }
    201 
    202   // Iterators
    203   child_range children() {
    204     return child_range(&SubExprs[0], &SubExprs[END]);
    205   }
    206 };
    207 
    208 /// \brief Representation of a Microsoft __if_exists or __if_not_exists
    209 /// statement with a dependent name.
    210 ///
    211 /// The __if_exists statement can be used to include a sequence of statements
    212 /// in the program only when a particular dependent name does not exist. For
    213 /// example:
    214 ///
    215 /// \code
    216 /// template<typename T>
    217 /// void call_foo(T &t) {
    218 ///   __if_exists (T::foo) {
    219 ///     t.foo(); // okay: only called when T::foo exists.
    220 ///   }
    221 /// }
    222 /// \endcode
    223 ///
    224 /// Similarly, the __if_not_exists statement can be used to include the
    225 /// statements when a particular name does not exist.
    226 ///
    227 /// Note that this statement only captures __if_exists and __if_not_exists
    228 /// statements whose name is dependent. All non-dependent cases are handled
    229 /// directly in the parser, so that they don't introduce a new scope. Clang
    230 /// introduces scopes in the dependent case to keep names inside the compound
    231 /// statement from leaking out into the surround statements, which would
    232 /// compromise the template instantiation model. This behavior differs from
    233 /// Visual C++ (which never introduces a scope), but is a fairly reasonable
    234 /// approximation of the VC++ behavior.
    235 class MSDependentExistsStmt : public Stmt {
    236   SourceLocation KeywordLoc;
    237   bool IsIfExists;
    238   NestedNameSpecifierLoc QualifierLoc;
    239   DeclarationNameInfo NameInfo;
    240   Stmt *SubStmt;
    241 
    242   friend class ASTReader;
    243   friend class ASTStmtReader;
    244 
    245 public:
    246   MSDependentExistsStmt(SourceLocation KeywordLoc, bool IsIfExists,
    247                         NestedNameSpecifierLoc QualifierLoc,
    248                         DeclarationNameInfo NameInfo,
    249                         CompoundStmt *SubStmt)
    250   : Stmt(MSDependentExistsStmtClass),
    251     KeywordLoc(KeywordLoc), IsIfExists(IsIfExists),
    252     QualifierLoc(QualifierLoc), NameInfo(NameInfo),
    253     SubStmt(reinterpret_cast<Stmt *>(SubStmt)) { }
    254 
    255   /// \brief Retrieve the location of the __if_exists or __if_not_exists
    256   /// keyword.
    257   SourceLocation getKeywordLoc() const { return KeywordLoc; }
    258 
    259   /// \brief Determine whether this is an __if_exists statement.
    260   bool isIfExists() const { return IsIfExists; }
    261 
    262   /// \brief Determine whether this is an __if_exists statement.
    263   bool isIfNotExists() const { return !IsIfExists; }
    264 
    265   /// \brief Retrieve the nested-name-specifier that qualifies this name, if
    266   /// any.
    267   NestedNameSpecifierLoc getQualifierLoc() const { return QualifierLoc; }
    268 
    269   /// \brief Retrieve the name of the entity we're testing for, along with
    270   /// location information
    271   DeclarationNameInfo getNameInfo() const { return NameInfo; }
    272 
    273   /// \brief Retrieve the compound statement that will be included in the
    274   /// program only if the existence of the symbol matches the initial keyword.
    275   CompoundStmt *getSubStmt() const {
    276     return reinterpret_cast<CompoundStmt *>(SubStmt);
    277   }
    278 
    279   SourceLocation getLocStart() const LLVM_READONLY { return KeywordLoc; }
    280   SourceLocation getLocEnd() const LLVM_READONLY { return SubStmt->getLocEnd();}
    281 
    282   child_range children() {
    283     return child_range(&SubStmt, &SubStmt+1);
    284   }
    285 
    286   static bool classof(const Stmt *T) {
    287     return T->getStmtClass() == MSDependentExistsStmtClass;
    288   }
    289 };
    290 
    291 /// \brief Represents the body of a coroutine. This wraps the normal function
    292 /// body and holds the additional semantic context required to set up and tear
    293 /// down the coroutine frame.
    294 class CoroutineBodyStmt : public Stmt {
    295   enum SubStmt {
    296     Body,          ///< The body of the coroutine.
    297     Promise,       ///< The promise statement.
    298     InitSuspend,   ///< The initial suspend statement, run before the body.
    299     FinalSuspend,  ///< The final suspend statement, run after the body.
    300     OnException,   ///< Handler for exceptions thrown in the body.
    301     OnFallthrough, ///< Handler for control flow falling off the body.
    302     ReturnValue,   ///< Return value for thunk function.
    303     FirstParamMove ///< First offset for move construction of parameter copies.
    304   };
    305   Stmt *SubStmts[SubStmt::FirstParamMove];
    306 
    307   friend class ASTStmtReader;
    308 public:
    309   CoroutineBodyStmt(Stmt *Body, Stmt *Promise, Stmt *InitSuspend,
    310                     Stmt *FinalSuspend, Stmt *OnException, Stmt *OnFallthrough,
    311                     Expr *ReturnValue, ArrayRef<Expr *> ParamMoves)
    312       : Stmt(CoroutineBodyStmtClass) {
    313     SubStmts[CoroutineBodyStmt::Body] = Body;
    314     SubStmts[CoroutineBodyStmt::Promise] = Promise;
    315     SubStmts[CoroutineBodyStmt::InitSuspend] = InitSuspend;
    316     SubStmts[CoroutineBodyStmt::FinalSuspend] = FinalSuspend;
    317     SubStmts[CoroutineBodyStmt::OnException] = OnException;
    318     SubStmts[CoroutineBodyStmt::OnFallthrough] = OnFallthrough;
    319     SubStmts[CoroutineBodyStmt::ReturnValue] = ReturnValue;
    320     // FIXME: Tail-allocate space for parameter move expressions and store them.
    321     assert(ParamMoves.empty() && "not implemented yet");
    322   }
    323 
    324   /// \brief Retrieve the body of the coroutine as written. This will be either
    325   /// a CompoundStmt or a TryStmt.
    326   Stmt *getBody() const {
    327     return SubStmts[SubStmt::Body];
    328   }
    329 
    330   Stmt *getPromiseDeclStmt() const { return SubStmts[SubStmt::Promise]; }
    331   VarDecl *getPromiseDecl() const {
    332     return cast<VarDecl>(cast<DeclStmt>(getPromiseDeclStmt())->getSingleDecl());
    333   }
    334 
    335   Stmt *getInitSuspendStmt() const { return SubStmts[SubStmt::InitSuspend]; }
    336   Stmt *getFinalSuspendStmt() const { return SubStmts[SubStmt::FinalSuspend]; }
    337 
    338   Stmt *getExceptionHandler() const { return SubStmts[SubStmt::OnException]; }
    339   Stmt *getFallthroughHandler() const {
    340     return SubStmts[SubStmt::OnFallthrough];
    341   }
    342 
    343   Expr *getReturnValueInit() const {
    344     return cast<Expr>(SubStmts[SubStmt::ReturnValue]);
    345   }
    346 
    347   SourceLocation getLocStart() const LLVM_READONLY {
    348     return getBody()->getLocStart();
    349   }
    350   SourceLocation getLocEnd() const LLVM_READONLY {
    351     return getBody()->getLocEnd();
    352   }
    353 
    354   child_range children() {
    355     return child_range(SubStmts, SubStmts + SubStmt::FirstParamMove);
    356   }
    357 
    358   static bool classof(const Stmt *T) {
    359     return T->getStmtClass() == CoroutineBodyStmtClass;
    360   }
    361 };
    362 
    363 /// \brief Represents a 'co_return' statement in the C++ Coroutines TS.
    364 ///
    365 /// This statament models the initialization of the coroutine promise
    366 /// (encapsulating the eventual notional return value) from an expression
    367 /// (or braced-init-list), followed by termination of the coroutine.
    368 ///
    369 /// This initialization is modeled by the evaluation of the operand
    370 /// followed by a call to one of:
    371 ///   <promise>.return_value(<operand>)
    372 ///   <promise>.return_void()
    373 /// which we name the "promise call".
    374 class CoreturnStmt : public Stmt {
    375   SourceLocation CoreturnLoc;
    376 
    377   enum SubStmt { Operand, PromiseCall, Count };
    378   Stmt *SubStmts[SubStmt::Count];
    379 
    380   friend class ASTStmtReader;
    381 public:
    382   CoreturnStmt(SourceLocation CoreturnLoc, Stmt *Operand, Stmt *PromiseCall)
    383       : Stmt(CoreturnStmtClass), CoreturnLoc(CoreturnLoc) {
    384     SubStmts[SubStmt::Operand] = Operand;
    385     SubStmts[SubStmt::PromiseCall] = PromiseCall;
    386   }
    387 
    388   SourceLocation getKeywordLoc() const { return CoreturnLoc; }
    389 
    390   /// \brief Retrieve the operand of the 'co_return' statement. Will be nullptr
    391   /// if none was specified.
    392   Expr *getOperand() const { return static_cast<Expr*>(SubStmts[Operand]); }
    393 
    394   /// \brief Retrieve the promise call that results from this 'co_return'
    395   /// statement. Will be nullptr if either the coroutine has not yet been
    396   /// finalized or the coroutine has no eventual return type.
    397   Expr *getPromiseCall() const {
    398     return static_cast<Expr*>(SubStmts[PromiseCall]);
    399   }
    400 
    401   SourceLocation getLocStart() const LLVM_READONLY { return CoreturnLoc; }
    402   SourceLocation getLocEnd() const LLVM_READONLY {
    403     return getOperand()->getLocEnd();
    404   }
    405 
    406   child_range children() {
    407     return child_range(SubStmts, SubStmts + SubStmt::Count);
    408   }
    409 
    410   static bool classof(const Stmt *T) {
    411     return T->getStmtClass() == CoreturnStmtClass;
    412   }
    413 };
    414 
    415 }  // end namespace clang
    416 
    417 #endif
    418