EIC code displayed by LXR master/​include/​clang/​Sema/​ScopeInfo.h	Source navigation Diff markup Identifier search General search
	Version: master test Revert   Change

File indexing completed on 2026-05-10 08:37:01

 //===- ScopeInfo.h - Information about a semantic context -------*- 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
 //
 //===----------------------------------------------------------------------===//
 //
 // This file defines FunctionScopeInfo and its subclasses, which contain
 // information about a single function, block, lambda, or method body.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CLANG_SEMA_SCOPEINFO_H
 #define LLVM_CLANG_SEMA_SCOPEINFO_H
 
 #include "clang/AST/Expr.h"
 #include "clang/AST/ExprCXX.h"
 #include "clang/AST/Type.h"
 #include "clang/Basic/CapturedStmt.h"
 #include "clang/Basic/LLVM.h"
 #include "clang/Basic/PartialDiagnostic.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Sema/CleanupInfo.h"
 #include "clang/Sema/DeclSpec.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/TinyPtrVector.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/ErrorHandling.h"
 #include <algorithm>
 #include <cassert>
 #include <utility>
 
 namespace clang {
 
 class BlockDecl;
 class CapturedDecl;
 class CXXMethodDecl;
 class CXXRecordDecl;
 class ImplicitParamDecl;
 class NamedDecl;
 class ObjCIvarRefExpr;
 class ObjCMessageExpr;
 class ObjCPropertyDecl;
 class ObjCPropertyRefExpr;
 class ParmVarDecl;
 class RecordDecl;
 class ReturnStmt;
 class Scope;
 class Stmt;
 class SwitchStmt;
 class TemplateParameterList;
 class VarDecl;
 
 namespace sema {
 
 /// Contains information about the compound statement currently being
 /// parsed.
 class CompoundScopeInfo {
 public:
   /// Whether this compound statement contains `for' or `while' loops
   /// with empty bodies.
   bool HasEmptyLoopBodies = false;
 
   /// Whether this compound statement corresponds to a GNU statement
   /// expression.
   bool IsStmtExpr;
 
   /// FP options at the beginning of the compound statement, prior to
   /// any pragma.
   FPOptions InitialFPFeatures;
 
   CompoundScopeInfo(bool IsStmtExpr, FPOptions FPO)
       : IsStmtExpr(IsStmtExpr), InitialFPFeatures(FPO) {}
 
   void setHasEmptyLoopBodies() {
     HasEmptyLoopBodies = true;
   }
 };
 
 class PossiblyUnreachableDiag {
 public:
   PartialDiagnostic PD;
   SourceLocation Loc;
   llvm::TinyPtrVector<const Stmt*> Stmts;
 
   PossiblyUnreachableDiag(const PartialDiagnostic &PD, SourceLocation Loc,
                           ArrayRef<const Stmt *> Stmts)
       : PD(PD), Loc(Loc), Stmts(Stmts) {}
 };
 
 enum class FirstCoroutineStmtKind { CoReturn, CoAwait, CoYield };
 
 /// Retains information about a function, method, or block that is
 /// currently being parsed.
 class FunctionScopeInfo {
 protected:
   enum ScopeKind {
     SK_Function,
     SK_Block,
     SK_Lambda,
     SK_CapturedRegion
   };
 
 public:
   /// What kind of scope we are describing.
   ScopeKind Kind : 3;
 
   /// Whether this function contains a VLA, \@try, try, C++
   /// initializer, or anything else that can't be jumped past.
   bool HasBranchProtectedScope : 1;
 
   /// Whether this function contains any switches or direct gotos.
   bool HasBranchIntoScope : 1;
 
   /// Whether this function contains any indirect gotos.
   bool HasIndirectGoto : 1;
 
   /// Whether this function contains any statement marked with
   /// \c [[clang::musttail]].
   bool HasMustTail : 1;
 
   /// Whether a statement was dropped because it was invalid.
   bool HasDroppedStmt : 1;
 
   /// True if current scope is for OpenMP declare reduction combiner.
   bool HasOMPDeclareReductionCombiner : 1;
 
   /// Whether there is a fallthrough statement in this function.
   bool HasFallthroughStmt : 1;
 
   /// Whether this function uses constrained floating point intrinsics
   bool UsesFPIntrin : 1;
 
   /// Whether we make reference to a declaration that could be
   /// unavailable.
   bool HasPotentialAvailabilityViolations : 1;
 
   /// A flag that is set when parsing a method that must call super's
   /// implementation, such as \c -dealloc, \c -finalize, or any method marked
   /// with \c __attribute__((objc_requires_super)).
   bool ObjCShouldCallSuper : 1;
 
   /// True when this is a method marked as a designated initializer.
   bool ObjCIsDesignatedInit : 1;
 
   /// This starts true for a method marked as designated initializer and will
   /// be set to false if there is an invocation to a designated initializer of
   /// the super class.
   bool ObjCWarnForNoDesignatedInitChain : 1;
 
   /// True when this is an initializer method not marked as a designated
   /// initializer within a class that has at least one initializer marked as a
   /// designated initializer.
   bool ObjCIsSecondaryInit : 1;
 
   /// This starts true for a secondary initializer method and will be set to
   /// false if there is an invocation of an initializer on 'self'.
   bool ObjCWarnForNoInitDelegation : 1;
 
   /// True only when this function has not already built, or attempted
   /// to build, the initial and final coroutine suspend points
   bool NeedsCoroutineSuspends : 1;
 
   /// An enumeration representing the kind of the first coroutine statement
   /// in the function. One of co_return, co_await, or co_yield.
   LLVM_PREFERRED_TYPE(FirstCoroutineStmtKind)
   unsigned char FirstCoroutineStmtKind : 2;
 
   /// Whether we found an immediate-escalating expression.
   bool FoundImmediateEscalatingExpression : 1;
 
   /// First coroutine statement in the current function.
   /// (ex co_return, co_await, co_yield)
   SourceLocation FirstCoroutineStmtLoc;
 
   /// First 'return' statement in the current function.
   SourceLocation FirstReturnLoc;
 
   /// First C++ 'try' or ObjC @try statement in the current function.
   SourceLocation FirstCXXOrObjCTryLoc;
   enum { TryLocIsCXX, TryLocIsObjC, Unknown } FirstTryType = Unknown;
 
   /// First SEH '__try' statement in the current function.
   SourceLocation FirstSEHTryLoc;
 
   /// First use of a VLA within the current function.
   SourceLocation FirstVLALoc;
 
 private:
   /// Used to determine if errors occurred in this function or block.
   DiagnosticErrorTrap ErrorTrap;
 
 public:
   /// A SwitchStmt, along with a flag indicating if its list of case statements
   /// is incomplete (because we dropped an invalid one while parsing).
   using SwitchInfo = llvm::PointerIntPair<SwitchStmt*, 1, bool>;
 
   /// SwitchStack - This is the current set of active switch statements in the
   /// block.
   SmallVector<SwitchInfo, 8> SwitchStack;
 
   /// The list of return statements that occur within the function or
   /// block, if there is any chance of applying the named return value
   /// optimization, or if we need to infer a return type.
   SmallVector<ReturnStmt*, 4> Returns;
 
   /// The promise object for this coroutine, if any.
   VarDecl *CoroutinePromise = nullptr;
 
   /// A mapping between the coroutine function parameters that were moved
   /// to the coroutine frame, and their move statements.
   llvm::SmallMapVector<ParmVarDecl *, Stmt *, 4> CoroutineParameterMoves;
 
   /// The initial and final coroutine suspend points.
   std::pair<Stmt *, Stmt *> CoroutineSuspends;
 
   /// The stack of currently active compound statement scopes in the
   /// function.
   SmallVector<CompoundScopeInfo, 4> CompoundScopes;
 
   /// The set of blocks that are introduced in this function.
   llvm::SmallPtrSet<const BlockDecl *, 1> Blocks;
 
   /// The set of __block variables that are introduced in this function.
   llvm::TinyPtrVector<VarDecl *> ByrefBlockVars;
 
   /// A list of PartialDiagnostics created but delayed within the
   /// current function scope.  These diagnostics are vetted for reachability
   /// prior to being emitted.
   SmallVector<PossiblyUnreachableDiag, 4> PossiblyUnreachableDiags;
 
   /// A list of parameters which have the nonnull attribute and are
   /// modified in the function.
   llvm::SmallPtrSet<const ParmVarDecl *, 8> ModifiedNonNullParams;
 
   /// The set of GNU address of label extension "&&label".
   llvm::SmallVector<AddrLabelExpr *, 4> AddrLabels;
 
 public:
   /// Represents a simple identification of a weak object.
   ///
   /// Part of the implementation of -Wrepeated-use-of-weak.
   ///
   /// This is used to determine if two weak accesses refer to the same object.
   /// Here are some examples of how various accesses are "profiled":
   ///
   /// Access Expression |     "Base" Decl     |          "Property" Decl
   /// :---------------: | :-----------------: | :------------------------------:
   /// self.property     | self (VarDecl)      | property (ObjCPropertyDecl)
   /// self.implicitProp | self (VarDecl)      | -implicitProp (ObjCMethodDecl)
   /// self->ivar.prop   | ivar (ObjCIvarDecl) | prop (ObjCPropertyDecl)
   /// cxxObj.obj.prop   | obj (FieldDecl)     | prop (ObjCPropertyDecl)
   /// [self foo].prop   | 0 (unknown)         | prop (ObjCPropertyDecl)
   /// self.prop1.prop2  | prop1 (ObjCPropertyDecl)    | prop2 (ObjCPropertyDecl)
   /// MyClass.prop      | MyClass (ObjCInterfaceDecl) | -prop (ObjCMethodDecl)
   /// MyClass.foo.prop  | +foo (ObjCMethodDecl)       | -prop (ObjCPropertyDecl)
   /// weakVar           | 0 (known)           | weakVar (VarDecl)
   /// self->weakIvar    | self (VarDecl)      | weakIvar (ObjCIvarDecl)
   ///
   /// Objects are identified with only two Decls to make it reasonably fast to
   /// compare them.
   class WeakObjectProfileTy {
     /// The base object decl, as described in the class documentation.
     ///
     /// The extra flag is "true" if the Base and Property are enough to uniquely
     /// identify the object in memory.
     ///
     /// \sa isExactProfile()
     using BaseInfoTy = llvm::PointerIntPair<const NamedDecl *, 1, bool>;
     BaseInfoTy Base;
 
     /// The "property" decl, as described in the class documentation.
     ///
     /// Note that this may not actually be an ObjCPropertyDecl, e.g. in the
     /// case of "implicit" properties (regular methods accessed via dot syntax).
     const NamedDecl *Property = nullptr;
 
     /// Used to find the proper base profile for a given base expression.
     static BaseInfoTy getBaseInfo(const Expr *BaseE);
 
     inline WeakObjectProfileTy();
     static inline WeakObjectProfileTy getSentinel();
 
   public:
     WeakObjectProfileTy(const ObjCPropertyRefExpr *RE);
     WeakObjectProfileTy(const Expr *Base, const ObjCPropertyDecl *Property);
     WeakObjectProfileTy(const DeclRefExpr *RE);
     WeakObjectProfileTy(const ObjCIvarRefExpr *RE);
 
     const NamedDecl *getBase() const { return Base.getPointer(); }
     const NamedDecl *getProperty() const { return Property; }
 
     /// Returns true if the object base specifies a known object in memory,
     /// rather than, say, an instance variable or property of another object.
     ///
     /// Note that this ignores the effects of aliasing; that is, \c foo.bar is
     /// considered an exact profile if \c foo is a local variable, even if
     /// another variable \c foo2 refers to the same object as \c foo.
     ///
     /// For increased precision, accesses with base variables that are
     /// properties or ivars of 'self' (e.g. self.prop1.prop2) are considered to
     /// be exact, though this is not true for arbitrary variables
     /// (foo.prop1.prop2).
     bool isExactProfile() const {
       return Base.getInt();
     }
 
     bool operator==(const WeakObjectProfileTy &Other) const {
       return Base == Other.Base && Property == Other.Property;
     }
 
     // For use in DenseMap.
     // We can't specialize the usual llvm::DenseMapInfo at the end of the file
     // because by that point the DenseMap in FunctionScopeInfo has already been
     // instantiated.
     class DenseMapInfo {
     public:
       static inline WeakObjectProfileTy getEmptyKey() {
         return WeakObjectProfileTy();
       }
 
       static inline WeakObjectProfileTy getTombstoneKey() {
         return WeakObjectProfileTy::getSentinel();
       }
 
       static unsigned getHashValue(const WeakObjectProfileTy &Val) {
         using Pair = std::pair<BaseInfoTy, const NamedDecl *>;
 
         return llvm::DenseMapInfo<Pair>::getHashValue(Pair(Val.Base,
                                                            Val.Property));
       }
 
       static bool isEqual(const WeakObjectProfileTy &LHS,
                           const WeakObjectProfileTy &RHS) {
         return LHS == RHS;
       }
     };
   };
 
   /// Represents a single use of a weak object.
   ///
   /// Stores both the expression and whether the access is potentially unsafe
   /// (i.e. it could potentially be warned about).
   ///
   /// Part of the implementation of -Wrepeated-use-of-weak.
   class WeakUseTy {
     llvm::PointerIntPair<const Expr *, 1, bool> Rep;
 
   public:
     WeakUseTy(const Expr *Use, bool IsRead) : Rep(Use, IsRead) {}
 
     const Expr *getUseExpr() const { return Rep.getPointer(); }
     bool isUnsafe() const { return Rep.getInt(); }
     void markSafe() { Rep.setInt(false); }
 
     bool operator==(const WeakUseTy &Other) const {
       return Rep == Other.Rep;
     }
   };
 
   /// Used to collect uses of a particular weak object in a function body.
   ///
   /// Part of the implementation of -Wrepeated-use-of-weak.
   using WeakUseVector = SmallVector<WeakUseTy, 4>;
 
   /// Used to collect all uses of weak objects in a function body.
   ///
   /// Part of the implementation of -Wrepeated-use-of-weak.
   using WeakObjectUseMap =
       llvm::SmallDenseMap<WeakObjectProfileTy, WeakUseVector, 8,
                           WeakObjectProfileTy::DenseMapInfo>;
 
 private:
   /// Used to collect all uses of weak objects in this function body.
   ///
   /// Part of the implementation of -Wrepeated-use-of-weak.
   WeakObjectUseMap WeakObjectUses;
 
 protected:
   FunctionScopeInfo(const FunctionScopeInfo&) = default;
 
 public:
   FunctionScopeInfo(DiagnosticsEngine &Diag)
       : Kind(SK_Function), HasBranchProtectedScope(false),
         HasBranchIntoScope(false), HasIndirectGoto(false), HasMustTail(false),
         HasDroppedStmt(false), HasOMPDeclareReductionCombiner(false),
         HasFallthroughStmt(false), UsesFPIntrin(false),
         HasPotentialAvailabilityViolations(false), ObjCShouldCallSuper(false),
         ObjCIsDesignatedInit(false), ObjCWarnForNoDesignatedInitChain(false),
         ObjCIsSecondaryInit(false), ObjCWarnForNoInitDelegation(false),
         NeedsCoroutineSuspends(true), FoundImmediateEscalatingExpression(false),
         ErrorTrap(Diag) {}
 
   virtual ~FunctionScopeInfo();
 
   /// Determine whether an unrecoverable error has occurred within this
   /// function. Note that this may return false even if the function body is
   /// invalid, because the errors may be suppressed if they're caused by prior
   /// invalid declarations.
   ///
   /// FIXME: Migrate the caller of this to use containsErrors() instead once
   /// it's ready.
   bool hasUnrecoverableErrorOccurred() const {
     return ErrorTrap.hasUnrecoverableErrorOccurred();
   }
 
   /// Record that a weak object was accessed.
   ///
   /// Part of the implementation of -Wrepeated-use-of-weak.
   template <typename ExprT>
   inline void recordUseOfWeak(const ExprT *E, bool IsRead = true);
 
   void recordUseOfWeak(const ObjCMessageExpr *Msg,
                        const ObjCPropertyDecl *Prop);
 
   /// Record that a given expression is a "safe" access of a weak object (e.g.
   /// assigning it to a strong variable.)
   ///
   /// Part of the implementation of -Wrepeated-use-of-weak.
   void markSafeWeakUse(const Expr *E);
 
   const WeakObjectUseMap &getWeakObjectUses() const {
     return WeakObjectUses;
   }
 
   void setHasBranchIntoScope() {
     HasBranchIntoScope = true;
   }
 
   void setHasBranchProtectedScope() {
     HasBranchProtectedScope = true;
   }
 
   void setHasIndirectGoto() {
     HasIndirectGoto = true;
   }
 
   void setHasMustTail() { HasMustTail = true; }
 
   void setHasDroppedStmt() {
     HasDroppedStmt = true;
   }
 
   void setHasOMPDeclareReductionCombiner() {
     HasOMPDeclareReductionCombiner = true;
   }
 
   void setHasFallthroughStmt() {
     HasFallthroughStmt = true;
   }
 
   void setUsesFPIntrin() {
     UsesFPIntrin = true;
   }
 
   void setHasCXXTry(SourceLocation TryLoc) {
     setHasBranchProtectedScope();
     FirstCXXOrObjCTryLoc = TryLoc;
     FirstTryType = TryLocIsCXX;
   }
 
   void setHasObjCTry(SourceLocation TryLoc) {
     setHasBranchProtectedScope();
     FirstCXXOrObjCTryLoc = TryLoc;
     FirstTryType = TryLocIsObjC;
   }
 
   void setHasSEHTry(SourceLocation TryLoc) {
     setHasBranchProtectedScope();
     FirstSEHTryLoc = TryLoc;
   }
 
   void setHasVLA(SourceLocation VLALoc) {
     if (FirstVLALoc.isInvalid())
       FirstVLALoc = VLALoc;
   }
 
   bool NeedsScopeChecking() const {
     return !HasDroppedStmt && (HasIndirectGoto || HasMustTail ||
                                (HasBranchProtectedScope && HasBranchIntoScope));
   }
 
   // Add a block introduced in this function.
   void addBlock(const BlockDecl *BD) {
     Blocks.insert(BD);
   }
 
   // Add a __block variable introduced in this function.
   void addByrefBlockVar(VarDecl *VD) {
     ByrefBlockVars.push_back(VD);
   }
 
   bool isCoroutine() const { return !FirstCoroutineStmtLoc.isInvalid(); }
 
   void setFirstCoroutineStmt(SourceLocation Loc, StringRef Keyword) {
     assert(FirstCoroutineStmtLoc.isInvalid() &&
                    "first coroutine statement location already set");
     FirstCoroutineStmtLoc = Loc;
     FirstCoroutineStmtKind =
         llvm::StringSwitch<unsigned char>(Keyword)
             .Case("co_return",
                   llvm::to_underlying(FirstCoroutineStmtKind::CoReturn))
             .Case("co_await",
                   llvm::to_underlying(FirstCoroutineStmtKind::CoAwait))
             .Case("co_yield",
                   llvm::to_underlying(FirstCoroutineStmtKind::CoYield));
   }
 
   StringRef getFirstCoroutineStmtKeyword() const {
     assert(FirstCoroutineStmtLoc.isValid()
                    && "no coroutine statement available");
     auto Value =
         static_cast<enum FirstCoroutineStmtKind>(FirstCoroutineStmtKind);
     switch (Value) {
     case FirstCoroutineStmtKind::CoReturn:
       return "co_return";
     case FirstCoroutineStmtKind::CoAwait:
       return "co_await";
     case FirstCoroutineStmtKind::CoYield:
       return "co_yield";
     };
     llvm_unreachable("FirstCoroutineStmtKind has an invalid value");
   }
 
   void setNeedsCoroutineSuspends(bool value = true) {
     assert((!value || CoroutineSuspends.first == nullptr) &&
             "we already have valid suspend points");
     NeedsCoroutineSuspends = value;
   }
 
   bool hasInvalidCoroutineSuspends() const {
     return !NeedsCoroutineSuspends && CoroutineSuspends.first == nullptr;
   }
 
   void setCoroutineSuspends(Stmt *Initial, Stmt *Final) {
     assert(Initial && Final && "suspend points cannot be null");
     assert(CoroutineSuspends.first == nullptr && "suspend points already set");
     NeedsCoroutineSuspends = false;
     CoroutineSuspends.first = Initial;
     CoroutineSuspends.second = Final;
   }
 
   /// Clear out the information in this function scope, making it
   /// suitable for reuse.
   void Clear();
 
   bool isPlainFunction() const { return Kind == SK_Function; }
 };
 
 class Capture {
   // There are three categories of capture: capturing 'this', capturing
   // local variables, and C++1y initialized captures (which can have an
   // arbitrary initializer, and don't really capture in the traditional
   // sense at all).
   //
   // There are three ways to capture a local variable:
   //  - capture by copy in the C++11 sense,
   //  - capture by reference in the C++11 sense, and
   //  - __block capture.
   // Lambdas explicitly specify capture by copy or capture by reference.
   // For blocks, __block capture applies to variables with that annotation,
   // variables of reference type are captured by reference, and other
   // variables are captured by copy.
   enum CaptureKind {
     Cap_ByCopy, Cap_ByRef, Cap_Block, Cap_VLA
   };
 
   union {
     /// If Kind == Cap_VLA, the captured type.
     const VariableArrayType *CapturedVLA;
 
     /// Otherwise, the captured variable (if any).
     ValueDecl *CapturedVar;
   };
 
   /// The source location at which the first capture occurred.
   SourceLocation Loc;
 
   /// The location of the ellipsis that expands a parameter pack.
   SourceLocation EllipsisLoc;
 
   /// The type as it was captured, which is the type of the non-static data
   /// member that would hold the capture.
   QualType CaptureType;
 
   /// The CaptureKind of this capture.
   LLVM_PREFERRED_TYPE(CaptureKind)
   unsigned Kind : 2;
 
   /// Whether this is a nested capture (a capture of an enclosing capturing
   /// scope's capture).
   LLVM_PREFERRED_TYPE(bool)
   unsigned Nested : 1;
 
   /// Whether this is a capture of '*this'.
   LLVM_PREFERRED_TYPE(bool)
   unsigned CapturesThis : 1;
 
   /// Whether an explicit capture has been odr-used in the body of the
   /// lambda.
   LLVM_PREFERRED_TYPE(bool)
   unsigned ODRUsed : 1;
 
   /// Whether an explicit capture has been non-odr-used in the body of
   /// the lambda.
   LLVM_PREFERRED_TYPE(bool)
   unsigned NonODRUsed : 1;
 
   /// Whether the capture is invalid (a capture was required but the entity is
   /// non-capturable).
   LLVM_PREFERRED_TYPE(bool)
   unsigned Invalid : 1;
 
 public:
   Capture(ValueDecl *Var, bool Block, bool ByRef, bool IsNested,
           SourceLocation Loc, SourceLocation EllipsisLoc, QualType CaptureType,
           bool Invalid)
       : CapturedVar(Var), Loc(Loc), EllipsisLoc(EllipsisLoc),
         CaptureType(CaptureType), Kind(Block   ? Cap_Block
                                        : ByRef ? Cap_ByRef
                                                : Cap_ByCopy),
         Nested(IsNested), CapturesThis(false), ODRUsed(false),
         NonODRUsed(false), Invalid(Invalid) {}
 
   enum IsThisCapture { ThisCapture };
   Capture(IsThisCapture, bool IsNested, SourceLocation Loc,
           QualType CaptureType, const bool ByCopy, bool Invalid)
       : Loc(Loc), CaptureType(CaptureType),
         Kind(ByCopy ? Cap_ByCopy : Cap_ByRef), Nested(IsNested),
         CapturesThis(true), ODRUsed(false), NonODRUsed(false),
         Invalid(Invalid) {}
 
   enum IsVLACapture { VLACapture };
   Capture(IsVLACapture, const VariableArrayType *VLA, bool IsNested,
           SourceLocation Loc, QualType CaptureType)
       : CapturedVLA(VLA), Loc(Loc), CaptureType(CaptureType), Kind(Cap_VLA),
         Nested(IsNested), CapturesThis(false), ODRUsed(false),
         NonODRUsed(false), Invalid(false) {}
 
   bool isThisCapture() const { return CapturesThis; }
   bool isVariableCapture() const {
     return !isThisCapture() && !isVLATypeCapture();
   }
 
   bool isCopyCapture() const { return Kind == Cap_ByCopy; }
   bool isReferenceCapture() const { return Kind == Cap_ByRef; }
   bool isBlockCapture() const { return Kind == Cap_Block; }
   bool isVLATypeCapture() const { return Kind == Cap_VLA; }
 
   bool isNested() const { return Nested; }
 
   bool isInvalid() const { return Invalid; }
 
   /// Determine whether this capture is an init-capture.
   bool isInitCapture() const;
 
   bool isODRUsed() const { return ODRUsed; }
   bool isNonODRUsed() const { return NonODRUsed; }
   void markUsed(bool IsODRUse) {
     if (IsODRUse)
       ODRUsed = true;
     else
       NonODRUsed = true;
   }
 
   ValueDecl *getVariable() const {
     assert(isVariableCapture());
     return CapturedVar;
   }
 
   const VariableArrayType *getCapturedVLAType() const {
     assert(isVLATypeCapture());
     return CapturedVLA;
   }
 
   /// Retrieve the location at which this variable was captured.
   SourceLocation getLocation() const { return Loc; }
 
   /// Retrieve the source location of the ellipsis, whose presence
   /// indicates that the capture is a pack expansion.
   SourceLocation getEllipsisLoc() const { return EllipsisLoc; }
 
   /// Retrieve the capture type for this capture, which is effectively
   /// the type of the non-static data member in the lambda/block structure
   /// that would store this capture.
   QualType getCaptureType() const { return CaptureType; }
 };
 
 class CapturingScopeInfo : public FunctionScopeInfo {
 protected:
   CapturingScopeInfo(const CapturingScopeInfo&) = default;
 
 public:
   enum ImplicitCaptureStyle {
     ImpCap_None, ImpCap_LambdaByval, ImpCap_LambdaByref, ImpCap_Block,
     ImpCap_CapturedRegion
   };
 
   ImplicitCaptureStyle ImpCaptureStyle;
 
   CapturingScopeInfo(DiagnosticsEngine &Diag, ImplicitCaptureStyle Style)
       : FunctionScopeInfo(Diag), ImpCaptureStyle(Style) {}
 
   /// CaptureMap - A map of captured variables to (index+1) into Captures.
   llvm::DenseMap<ValueDecl *, unsigned> CaptureMap;
 
   /// CXXThisCaptureIndex - The (index+1) of the capture of 'this';
   /// zero if 'this' is not captured.
   unsigned CXXThisCaptureIndex = 0;
 
   /// Captures - The captures.
   SmallVector<Capture, 4> Captures;
 
   /// - Whether the target type of return statements in this context
   /// is deduced (e.g. a lambda or block with omitted return type).
   bool HasImplicitReturnType = false;
 
   /// Whether this contains an unexpanded parameter pack.
   bool ContainsUnexpandedParameterPack = false;
 
   /// ReturnType - The target type of return statements in this context,
   /// or null if unknown.
   QualType ReturnType;
 
   /// Packs introduced by this, if any.
   SmallVector<NamedDecl *, 4> LocalPacks;
 
   void addCapture(ValueDecl *Var, bool isBlock, bool isByref, bool isNested,
                   SourceLocation Loc, SourceLocation EllipsisLoc,
                   QualType CaptureType, bool Invalid) {
     Captures.push_back(Capture(Var, isBlock, isByref, isNested, Loc,
                                EllipsisLoc, CaptureType, Invalid));
     CaptureMap[Var] = Captures.size();
   }
 
   void addVLATypeCapture(SourceLocation Loc, const VariableArrayType *VLAType,
                          QualType CaptureType) {
     Captures.push_back(Capture(Capture::VLACapture, VLAType,
                                /*FIXME: IsNested*/ false, Loc, CaptureType));
   }
 
   void addThisCapture(bool isNested, SourceLocation Loc, QualType CaptureType,
                       bool ByCopy);
 
   /// Determine whether the C++ 'this' is captured.
   bool isCXXThisCaptured() const { return CXXThisCaptureIndex != 0; }
 
   /// Retrieve the capture of C++ 'this', if it has been captured.
   Capture &getCXXThisCapture() {
     assert(isCXXThisCaptured() && "this has not been captured");
     return Captures[CXXThisCaptureIndex - 1];
   }
 
   /// Determine whether the given variable has been captured.
   bool isCaptured(ValueDecl *Var) const { return CaptureMap.count(Var); }
 
   /// Determine whether the given variable-array type has been captured.
   bool isVLATypeCaptured(const VariableArrayType *VAT) const;
 
   /// Retrieve the capture of the given variable, if it has been
   /// captured already.
   Capture &getCapture(ValueDecl *Var) {
     assert(isCaptured(Var) && "Variable has not been captured");
     return Captures[CaptureMap[Var] - 1];
   }
 
   const Capture &getCapture(ValueDecl *Var) const {
     llvm::DenseMap<ValueDecl *, unsigned>::const_iterator Known =
         CaptureMap.find(Var);
     assert(Known != CaptureMap.end() && "Variable has not been captured");
     return Captures[Known->second - 1];
   }
 
   static bool classof(const FunctionScopeInfo *FSI) {
     return FSI->Kind == SK_Block || FSI->Kind == SK_Lambda
                                  || FSI->Kind == SK_CapturedRegion;
   }
 };
 
 /// Retains information about a block that is currently being parsed.
 class BlockScopeInfo final : public CapturingScopeInfo {
 public:
   BlockDecl *TheDecl;
 
   /// TheScope - This is the scope for the block itself, which contains
   /// arguments etc.
   Scope *TheScope;
 
   /// BlockType - The function type of the block, if one was given.
   /// Its return type may be BuiltinType::Dependent.
   QualType FunctionType;
 
   BlockScopeInfo(DiagnosticsEngine &Diag, Scope *BlockScope, BlockDecl *Block)
       : CapturingScopeInfo(Diag, ImpCap_Block), TheDecl(Block),
         TheScope(BlockScope) {
     Kind = SK_Block;
   }
 
   ~BlockScopeInfo() override;
 
   static bool classof(const FunctionScopeInfo *FSI) {
     return FSI->Kind == SK_Block;
   }
 };
 
 /// Retains information about a captured region.
 class CapturedRegionScopeInfo final : public CapturingScopeInfo {
 public:
   /// The CapturedDecl for this statement.
   CapturedDecl *TheCapturedDecl;
 
   /// The captured record type.
   RecordDecl *TheRecordDecl;
 
   /// This is the enclosing scope of the captured region.
   Scope *TheScope;
 
   /// The implicit parameter for the captured variables.
   ImplicitParamDecl *ContextParam;
 
   /// The kind of captured region.
   unsigned short CapRegionKind;
 
   unsigned short OpenMPLevel;
   unsigned short OpenMPCaptureLevel;
 
   CapturedRegionScopeInfo(DiagnosticsEngine &Diag, Scope *S, CapturedDecl *CD,
                           RecordDecl *RD, ImplicitParamDecl *Context,
                           CapturedRegionKind K, unsigned OpenMPLevel,
                           unsigned OpenMPCaptureLevel)
       : CapturingScopeInfo(Diag, ImpCap_CapturedRegion),
         TheCapturedDecl(CD), TheRecordDecl(RD), TheScope(S),
         ContextParam(Context), CapRegionKind(K), OpenMPLevel(OpenMPLevel),
         OpenMPCaptureLevel(OpenMPCaptureLevel) {
     Kind = SK_CapturedRegion;
   }
 
   ~CapturedRegionScopeInfo() override;
 
   /// A descriptive name for the kind of captured region this is.
   StringRef getRegionName() const {
     switch (CapRegionKind) {
     case CR_Default:
       return "default captured statement";
     case CR_ObjCAtFinally:
       return "Objective-C @finally statement";
     case CR_OpenMP:
       return "OpenMP region";
     }
     llvm_unreachable("Invalid captured region kind!");
   }
 
   static bool classof(const FunctionScopeInfo *FSI) {
     return FSI->Kind == SK_CapturedRegion;
   }
 };
 
 class LambdaScopeInfo final :
     public CapturingScopeInfo, public InventedTemplateParameterInfo {
 public:
   /// The class that describes the lambda.
   CXXRecordDecl *Lambda = nullptr;
 
   /// The lambda's compiler-generated \c operator().
   CXXMethodDecl *CallOperator = nullptr;
 
   /// Indicate that we parsed the parameter list
   /// at which point the mutability of the lambda
   /// is known.
   bool AfterParameterList = true;
 
   ParmVarDecl *ExplicitObjectParameter = nullptr;
 
   /// Source range covering the lambda introducer [...].
   SourceRange IntroducerRange;
 
   /// Source location of the '&' or '=' specifying the default capture
   /// type, if any.
   SourceLocation CaptureDefaultLoc;
 
   /// The number of captures in the \c Captures list that are
   /// explicit captures.
   unsigned NumExplicitCaptures = 0;
 
   /// Whether this is a mutable lambda. Until the mutable keyword is parsed,
   /// we assume the lambda is mutable.
   bool Mutable = true;
 
   /// Whether the (empty) parameter list is explicit.
   bool ExplicitParams = false;
 
   /// Whether any of the capture expressions requires cleanups.
   CleanupInfo Cleanup;
 
   /// Source range covering the explicit template parameter list (if it exists).
   SourceRange ExplicitTemplateParamsRange;
 
   /// The requires-clause immediately following the explicit template parameter
   /// list, if any. (Note that there may be another requires-clause included as
   /// part of the lambda-declarator.)
   ExprResult RequiresClause;
 
   /// If this is a generic lambda, and the template parameter
   /// list has been created (from the TemplateParams) then store
   /// a reference to it (cache it to avoid reconstructing it).
   TemplateParameterList *GLTemplateParameterList = nullptr;
 
   /// Contains all variable-referring-expressions (i.e. DeclRefExprs
   ///  or MemberExprs) that refer to local variables in a generic lambda
   ///  or a lambda in a potentially-evaluated-if-used context.
   ///
   ///  Potentially capturable variables of a nested lambda that might need
   ///   to be captured by the lambda are housed here.
   ///  This is specifically useful for generic lambdas or
   ///  lambdas within a potentially evaluated-if-used context.
   ///  If an enclosing variable is named in an expression of a lambda nested
   ///  within a generic lambda, we don't always know whether the variable
   ///  will truly be odr-used (i.e. need to be captured) by that nested lambda,
   ///  until its instantiation. But we still need to capture it in the
   ///  enclosing lambda if all intervening lambdas can capture the variable.
   llvm::SmallVector<Expr*, 4> PotentiallyCapturingExprs;
 
   /// Contains all variable-referring-expressions that refer
   ///  to local variables that are usable as constant expressions and
   ///  do not involve an odr-use (they may still need to be captured
   ///  if the enclosing full-expression is instantiation dependent).
   llvm::SmallSet<Expr *, 8> NonODRUsedCapturingExprs;
 
   /// A map of explicit capture indices to their introducer source ranges.
   llvm::DenseMap<unsigned, SourceRange> ExplicitCaptureRanges;
 
   /// Contains all of the variables defined in this lambda that shadow variables
   /// that were defined in parent contexts. Used to avoid warnings when the
   /// shadowed variables are uncaptured by this lambda.
   struct ShadowedOuterDecl {
     const NamedDecl *VD;
     const NamedDecl *ShadowedDecl;
   };
   llvm::SmallVector<ShadowedOuterDecl, 4> ShadowingDecls;
 
   SourceLocation PotentialThisCaptureLocation;
 
   LambdaScopeInfo(DiagnosticsEngine &Diag)
       : CapturingScopeInfo(Diag, ImpCap_None) {
     Kind = SK_Lambda;
   }
 
   /// Note when all explicit captures have been added.
   void finishedExplicitCaptures() {
     NumExplicitCaptures = Captures.size();
   }
 
   static bool classof(const FunctionScopeInfo *FSI) {
     return FSI->Kind == SK_Lambda;
   }
 
   /// Is this scope known to be for a generic lambda? (This will be false until
   /// we parse a template parameter list or the first 'auto'-typed parameter).
   bool isGenericLambda() const {
     return !TemplateParams.empty() || GLTemplateParameterList;
   }
 
   /// Add a variable that might potentially be captured by the
   /// lambda and therefore the enclosing lambdas.
   ///
   /// This is also used by enclosing lambda's to speculatively capture
   /// variables that nested lambda's - depending on their enclosing
   /// specialization - might need to capture.
   /// Consider:
   /// void f(int, int); <-- don't capture
   /// void f(const int&, double); <-- capture
   /// void foo() {
   ///   const int x = 10;
   ///   auto L = [=](auto a) { // capture 'x'
   ///      return [=](auto b) {
   ///        f(x, a);  // we may or may not need to capture 'x'
   ///      };
   ///   };
   /// }
   void addPotentialCapture(Expr *VarExpr) {
     assert(isa<DeclRefExpr>(VarExpr) || isa<MemberExpr>(VarExpr) ||
            isa<FunctionParmPackExpr>(VarExpr));
     PotentiallyCapturingExprs.push_back(VarExpr);
   }
 
   void addPotentialThisCapture(SourceLocation Loc) {
     PotentialThisCaptureLocation = Loc;
   }
 
   bool hasPotentialThisCapture() const {
     return PotentialThisCaptureLocation.isValid();
   }
 
   /// Mark a variable's reference in a lambda as non-odr using.
   ///
   /// For generic lambdas, if a variable is named in a potentially evaluated
   /// expression, where the enclosing full expression is dependent then we
   /// must capture the variable (given a default capture).
   /// This is accomplished by recording all references to variables
   /// (DeclRefExprs or MemberExprs) within said nested lambda in its array of
   /// PotentialCaptures. All such variables have to be captured by that lambda,
   /// except for as described below.
   /// If that variable is usable as a constant expression and is named in a
   /// manner that does not involve its odr-use (e.g. undergoes
   /// lvalue-to-rvalue conversion, or discarded) record that it is so. Upon the
   /// act of analyzing the enclosing full expression (ActOnFinishFullExpr)
   /// if we can determine that the full expression is not instantiation-
   /// dependent, then we can entirely avoid its capture.
   ///
   ///   const int n = 0;
   ///   [&] (auto x) {
   ///     (void)+n + x;
   ///   };
   /// Interestingly, this strategy would involve a capture of n, even though
   /// it's obviously not odr-used here, because the full-expression is
   /// instantiation-dependent.  It could be useful to avoid capturing such
   /// variables, even when they are referred to in an instantiation-dependent
   /// expression, if we can unambiguously determine that they shall never be
   /// odr-used.  This would involve removal of the variable-referring-expression
   /// from the array of PotentialCaptures during the lvalue-to-rvalue
   /// conversions.  But per the working draft N3797, (post-chicago 2013) we must
   /// capture such variables.
   /// Before anyone is tempted to implement a strategy for not-capturing 'n',
   /// consider the insightful warning in:
   ///    /cfe-commits/Week-of-Mon-20131104/092596.html
   /// "The problem is that the set of captures for a lambda is part of the ABI
   ///  (since lambda layout can be made visible through inline functions and the
   ///  like), and there are no guarantees as to which cases we'll manage to build
   ///  an lvalue-to-rvalue conversion in, when parsing a template -- some
   ///  seemingly harmless change elsewhere in Sema could cause us to start or stop
   ///  building such a node. So we need a rule that anyone can implement and get
   ///  exactly the same result".
   void markVariableExprAsNonODRUsed(Expr *CapturingVarExpr) {
     assert(isa<DeclRefExpr>(CapturingVarExpr) ||
            isa<MemberExpr>(CapturingVarExpr) ||
            isa<FunctionParmPackExpr>(CapturingVarExpr));
     NonODRUsedCapturingExprs.insert(CapturingVarExpr);
   }
   bool isVariableExprMarkedAsNonODRUsed(Expr *CapturingVarExpr) const {
     assert(isa<DeclRefExpr>(CapturingVarExpr) ||
            isa<MemberExpr>(CapturingVarExpr) ||
            isa<FunctionParmPackExpr>(CapturingVarExpr));
     return NonODRUsedCapturingExprs.count(CapturingVarExpr);
   }
   void removePotentialCapture(Expr *E) {
     llvm::erase(PotentiallyCapturingExprs, E);
   }
   void clearPotentialCaptures() {
     PotentiallyCapturingExprs.clear();
     PotentialThisCaptureLocation = SourceLocation();
   }
   unsigned getNumPotentialVariableCaptures() const {
     return PotentiallyCapturingExprs.size();
   }
 
   bool hasPotentialCaptures() const {
     return getNumPotentialVariableCaptures() ||
                                   PotentialThisCaptureLocation.isValid();
   }
 
   void visitPotentialCaptures(
       llvm::function_ref<void(ValueDecl *, Expr *)> Callback) const;
 
   bool lambdaCaptureShouldBeConst() const;
 };
 
 FunctionScopeInfo::WeakObjectProfileTy::WeakObjectProfileTy()
     : Base(nullptr, false) {}
 
 FunctionScopeInfo::WeakObjectProfileTy
 FunctionScopeInfo::WeakObjectProfileTy::getSentinel() {
   FunctionScopeInfo::WeakObjectProfileTy Result;
   Result.Base.setInt(true);
   return Result;
 }
 
 template <typename ExprT>
 void FunctionScopeInfo::recordUseOfWeak(const ExprT *E, bool IsRead) {
   assert(E);
   WeakUseVector &Uses = WeakObjectUses[WeakObjectProfileTy(E)];
   Uses.push_back(WeakUseTy(E, IsRead));
 }
 
 inline void CapturingScopeInfo::addThisCapture(bool isNested,
                                                SourceLocation Loc,
                                                QualType CaptureType,
                                                bool ByCopy) {
   Captures.push_back(Capture(Capture::ThisCapture, isNested, Loc, CaptureType,
                              ByCopy, /*Invalid*/ false));
   CXXThisCaptureIndex = Captures.size();
 }
 
 } // namespace sema
 
 } // namespace clang
 
 #endif // LLVM_CLANG_SEMA_SCOPEINFO_H

This page was automatically generated by the 2.3.7 LXR engine. The LXR team