Introduce a new initialization entity for lambda captures, and

specialize location information and diagnostics for this entity.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150588 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/DiagnosticSemaKinds.td

@@ -4053,6 +4053,12 @@ let CategoryName = "Lambda Issue" in {
   def warn_falloff_nonvoid_lambda : Warning<
     "control reaches end of non-void lambda">,
     InGroup<ReturnType>;
+  def err_access_lambda_capture : Error<
+    // The ERRORs represent other special members that aren't constructors, in
+    // hopes that someone will bother noticing and reporting if they appear
+    "capture of variable '%0' as type %1 calls %select{private|protected}3 "
+    "%select{default |copy |move |*ERROR* |*ERROR* |*ERROR* |}2constructor">,
+    AccessControl;
 }
 
 def err_operator_arrow_circular : Error<

include/clang/Sema/Initialization.h

@@ -70,7 +70,10 @@ public:
     EK_BlockElement,
     /// \brief The entity being initialized is the real or imaginary part of a
     /// complex number.
-    EK_ComplexElement
+    EK_ComplexElement,
+    /// \brief The entity being initialized is the field that captures a 
+    /// variable in a lambda.
+    EK_LambdaCapture
   };
   
 private:
@@ -85,7 +88,7 @@ private:
   QualType Type;
   
   union {
-    /// \brief When Kind == EK_Variable or EK_Member, the VarDecl or
+    /// \brief When Kind == EK_Variable, or EK_Member, the VarDecl or
     /// FieldDecl, respectively.
     DeclaratorDecl *VariableOrMember;
 
@@ -98,7 +101,7 @@ private:
     TypeSourceInfo *TypeInfo;
     
     struct {
-      /// \brief When Kind == EK_Result, EK_Exception, or EK_New, the
+      /// \brief When Kind == EK_Result, EK_Exception, EK_New, the
       /// location of the 'return', 'throw', or 'new' keyword,
       /// respectively. When Kind == EK_Temporary, the location where
       /// the temporary is being created.
@@ -118,6 +121,14 @@ private:
     /// EK_ComplexElement, the index of the array or vector element being
     /// initialized. 
     unsigned Index;
+    
+    struct {
+      /// \brief The variable being captured by an EK_LambdaCapture.
+      VarDecl *Var;
+      
+      /// \brief The source location at which the capture occurs.
+      unsigned Location;
+    } Capture;
   };
 
   InitializedEntity() { }
@@ -147,6 +158,14 @@ private:
   InitializedEntity(ASTContext &Context, unsigned Index, 
                     const InitializedEntity &Parent);
 
+  /// \brief Create the initialization entity for a lambda capture.
+  InitializedEntity(VarDecl *Var, FieldDecl *Field, SourceLocation Loc)
+    : Kind(EK_LambdaCapture), Parent(0), Type(Field->getType()) 
+  {
+    Capture.Var = Var;
+    Capture.Location = Loc.getRawEncoding();
+  }
+  
 public:
   /// \brief Create the initialization entity for a variable.
   static InitializedEntity InitializeVariable(VarDecl *Var) {
@@ -246,6 +265,13 @@ public:
     return InitializedEntity(Context, Index, Parent);
   }
 
+  /// \brief Create the initialization entity for a lambda capture.
+  static InitializedEntity InitializeLambdaCapture(VarDecl *Var,
+                                                   FieldDecl *Field,
+                                                   SourceLocation Loc) {
+    return InitializedEntity(Var, Field, Loc);
+  }
+                                                   
   /// \brief Determine the kind of initialization.
   EntityKind getKind() const { return Kind; }
   
@@ -317,6 +343,19 @@ public:
            EK_ComplexElement);
     this->Index = Index;
   }
+
+  /// \brief Retrieve the variable for a captured variable in a lambda.
+  VarDecl *getCapturedVar() const {
+    assert(getKind() == EK_LambdaCapture && "Not a lambda capture!");
+    return Capture.Var;
+  }
+  
+  /// \brief Determine the location of the capture when initializing
+  /// field from a captured variable in a lambda.
+  SourceLocation getCaptureLoc() const {
+    assert(getKind() == EK_LambdaCapture && "Not a lambda capture!");
+    return SourceLocation::getFromRawEncoding(Capture.Location);
+  }
 };
   
 /// \brief Describes the kind of initialization being performed, along with 

lib/Sema/SemaAccess.cpp

@@ -1481,6 +1481,13 @@ Sema::AccessResult Sema::CheckConstructorAccess(SourceLocation UseLoc,
     break;
   }
 
+  case InitializedEntity::EK_LambdaCapture: {
+    const VarDecl *Var = Entity.getCapturedVar();
+    PD = PDiag(diag::err_access_lambda_capture);
+    PD << Var->getName() << Entity.getType() << getSpecialMember(Constructor);
+    break;
+  }
+
   }
 
   return CheckConstructorAccess(UseLoc, Constructor, Access, PD);

lib/Sema/SemaExpr.cpp

@@ -9625,8 +9625,6 @@ static ExprResult captureInLambda(Sema &S, LambdaScopeInfo *LSI,
   //   direct-initialized in increasing subscript order.) These
   //   initializations are performed in the (unspecified) order in
   //   which the non-static data members are declared.
-  //
-  // FIXME: Introduce an initialization entity for lambda captures.
       
   // Introduce a new evaluation context for the initialization, so
   // that temporaries introduced as part of the capture are retained
@@ -9697,7 +9695,8 @@ static ExprResult captureInLambda(Sema &S, LambdaScopeInfo *LSI,
   // of array-subscript entities. 
   SmallVector<InitializedEntity, 4> Entities;
   Entities.reserve(1 + IndexVariables.size());
-  Entities.push_back(InitializedEntity::InitializeMember(Field));
+  Entities.push_back(
+    InitializedEntity::InitializeLambdaCapture(Var, Field, Loc));
   for (unsigned I = 0, N = IndexVariables.size(); I != N; ++I)
     Entities.push_back(InitializedEntity::InitializeElement(S.Context,
                                                             0,

lib/Sema/SemaInit.cpp

@@ -2321,6 +2321,9 @@ DeclarationName InitializedEntity::getName() const {
   case EK_Member:
     return VariableOrMember->getDeclName();
 
+  case EK_LambdaCapture:
+    return Capture.Var->getDeclName();
+      
   case EK_Result:
   case EK_Exception:
   case EK_New:
@@ -2356,6 +2359,7 @@ DeclaratorDecl *InitializedEntity::getDecl() const {
   case EK_VectorElement:
   case EK_ComplexElement:
   case EK_BlockElement:
+  case EK_LambdaCapture:
     return 0;
   }
 
@@ -2379,6 +2383,7 @@ bool InitializedEntity::allowsNRVO() const {
   case EK_VectorElement:
   case EK_ComplexElement:
   case EK_BlockElement:
+  case EK_LambdaCapture:
     break;
   }
 
@@ -4210,6 +4215,7 @@ getAssignmentAction(const InitializedEntity &Entity) {
   case InitializedEntity::EK_VectorElement:
   case InitializedEntity::EK_ComplexElement:
   case InitializedEntity::EK_BlockElement:
+  case InitializedEntity::EK_LambdaCapture:
     return Sema::AA_Initializing;
   }
 
@@ -4231,6 +4237,7 @@ static bool shouldBindAsTemporary(const InitializedEntity &Entity) {
   case InitializedEntity::EK_ComplexElement:
   case InitializedEntity::EK_Exception:
   case InitializedEntity::EK_BlockElement:
+  case InitializedEntity::EK_LambdaCapture:
     return false;
 
   case InitializedEntity::EK_Parameter:
@@ -4253,6 +4260,7 @@ static bool shouldDestroyTemporary(const InitializedEntity &Entity) {
     case InitializedEntity::EK_VectorElement:
     case InitializedEntity::EK_ComplexElement:
     case InitializedEntity::EK_BlockElement:
+    case InitializedEntity::EK_LambdaCapture:
       return false;
 
     case InitializedEntity::EK_Variable:
@@ -4323,6 +4331,9 @@ static SourceLocation getInitializationLoc(const InitializedEntity &Entity,
   case InitializedEntity::EK_Variable:
     return Entity.getDecl()->getLocation();
 
+  case InitializedEntity::EK_LambdaCapture:
+    return Entity.getCaptureLoc();
+      
   case InitializedEntity::EK_ArrayElement:
   case InitializedEntity::EK_Member:
   case InitializedEntity::EK_Parameter:

test/CXX/expr/expr.prim/expr.prim.lambda/p14.cpp

@@ -4,12 +4,15 @@ template<typename T> void capture(const T&);
 
 class NonCopyable {
   NonCopyable(const NonCopyable&); // expected-note 2 {{implicitly declared private here}}
+public:
+  void foo() const;
 };
 
 void capture_by_copy(NonCopyable nc, NonCopyable &ncr) {
-  // FIXME: error messages should talk about capture
-  (void)[nc] { }; // expected-error{{field of type 'NonCopyable' has private copy constructor}}
-  (void)[ncr] { }; // expected-error{{field of type 'NonCopyable' has private copy constructor}}
+  (void)[nc] { }; // expected-error{{capture of variable 'nc' as type 'NonCopyable' calls private copy constructor}}
+  (void)[=] {
+    ncr.foo(); // expected-error{{capture of variable 'ncr' as type 'NonCopyable' calls private copy constructor}} 
+  }();
 }
 
 struct NonTrivial {