[cfe-commits] r151076 - in /cfe/trunk: include/clang/AST/DeclCXX.h include/clang/Sema/Sema.h lib/AST/DeclBase.cpp lib/AST/DeclCXX.cpp lib/Sema/SemaExpr.cpp lib/Sema/SemaLambda.cpp lib/Serialization/ASTReaderDecl.cpp lib/Serialization/ASTWriter.cp
Eli Friedman
eli.friedman at gmail.com
Tue Feb 21 12:15:14 PST 2012
On Tue, Feb 21, 2012 at 11:11 AM, Douglas Gregor <dgregor at apple.com> wrote:
> Author: dgregor
> Date: Tue Feb 21 13:11:17 2012
> New Revision: 151076
>
> URL: http://llvm.org/viewvc/llvm-project?rev=151076&view=rev
> Log:
> Improve our handling of lambda expressions that occur within default
> arguments. There are two aspects to this:
>
> - Make sure that when marking the declarations referenced in a
> default argument, we don't try to mark local variables, both because
> it's a waste of time and because the semantics are wrong: we're not
> in a place where we could capture these variables again even if it
> did make sense.
> - When a lambda expression occurs in a default argument of a
> function template, make sure that the corresponding closure type is
> considered dependent, so that it will get properly instantiated. The
> second bit is a bit of a hack; to fix it properly, we may have to
> rearchitect our handling of default arguments, parsing them only
> after creating the function definition. However, I'd like to
> separate that work from the lambdas work.
>
>
> Modified:
> cfe/trunk/include/clang/AST/DeclCXX.h
> cfe/trunk/include/clang/Sema/Sema.h
> cfe/trunk/lib/AST/DeclBase.cpp
> cfe/trunk/lib/AST/DeclCXX.cpp
> cfe/trunk/lib/Sema/SemaExpr.cpp
> cfe/trunk/lib/Sema/SemaLambda.cpp
> cfe/trunk/lib/Serialization/ASTReaderDecl.cpp
> cfe/trunk/lib/Serialization/ASTWriter.cpp
> cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p13.cpp
>
> Modified: cfe/trunk/include/clang/AST/DeclCXX.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/DeclCXX.h?rev=151076&r1=151075&r2=151076&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/AST/DeclCXX.h (original)
> +++ cfe/trunk/include/clang/AST/DeclCXX.h Tue Feb 21 13:11:17 2012
> @@ -560,18 +560,28 @@
> struct LambdaDefinitionData : public DefinitionData {
> typedef LambdaExpr::Capture Capture;
>
> - LambdaDefinitionData(CXXRecordDecl *D)
> - : DefinitionData(D), NumCaptures(0), NumExplicitCaptures(0),
> - ContextDecl(0), Captures(0)
> + LambdaDefinitionData(CXXRecordDecl *D, bool Dependent)
> + : DefinitionData(D), Dependent(Dependent), NumCaptures(0),
> + NumExplicitCaptures(0), ManglingNumber(0), ContextDecl(0), Captures(0)
> {
> IsLambda = true;
> }
>
> + /// \brief Whether this lambda is known to be dependent, even if its
> + /// context isn't dependent.
> + ///
> + /// A lambda with a non-dependent context can be dependent if it occurs
> + /// within the default argument of a function template, because the
> + /// lambda will have been created with the enclosing context as its
> + /// declaration context, rather than function. This is an unfortunate
> + /// artifact of having to parse the default arguments before
> + unsigned Dependent : 1;
> +
> /// \brief The number of captures in this lambda.
> unsigned NumCaptures : 16;
>
> /// \brief The number of explicit captures in this lambda.
> - unsigned NumExplicitCaptures : 16;
> + unsigned NumExplicitCaptures : 15;
>
> /// \brief The number used to indicate this lambda expression for name
> /// mangling in the Itanium C++ ABI.
> @@ -689,7 +699,7 @@
> IdentifierInfo *Id, CXXRecordDecl* PrevDecl=0,
> bool DelayTypeCreation = false);
> static CXXRecordDecl *CreateLambda(const ASTContext &C, DeclContext *DC,
> - SourceLocation Loc);
> + SourceLocation Loc, bool DependentLambda);
> static CXXRecordDecl *CreateDeserialized(const ASTContext &C, unsigned ID);
>
> bool isDynamicClass() const {
> @@ -1478,6 +1488,21 @@
> return getLambdaData().ContextDecl;
> }
>
> + /// \brief Determine whether this lambda expression was known to be dependent
> + /// at the time it was created, even if its context does not appear to be
> + /// dependent.
> + ///
> + /// This flag is a workaround for an issue with parsing, where default
> + /// arguments are parsed before their enclosing function declarations have
> + /// been created. This means that any lambda expressions within those
> + /// default arguments will have as their DeclContext the context enclosing
> + /// the function declaration, which may be non-dependent even when the
> + /// function declaration itself is dependent. This flag indicates when we
> + /// know that the lambda is dependent despite that.
> + bool isDependentLambda() const {
> + return isLambda() && getLambdaData().Dependent;
> + }
> +
> static bool classof(const Decl *D) { return classofKind(D->getKind()); }
> static bool classofKind(Kind K) {
> return K >= firstCXXRecord && K <= lastCXXRecord;
>
> Modified: cfe/trunk/include/clang/Sema/Sema.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=151076&r1=151075&r2=151076&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Sema/Sema.h (original)
> +++ cfe/trunk/include/clang/Sema/Sema.h Tue Feb 21 13:11:17 2012
> @@ -2386,7 +2386,8 @@
> QualType getCapturedDeclRefType(VarDecl *Var, SourceLocation Loc);
>
> void MarkDeclarationsReferencedInType(SourceLocation Loc, QualType T);
> - void MarkDeclarationsReferencedInExpr(Expr *E);
> + void MarkDeclarationsReferencedInExpr(Expr *E,
> + bool SkipLocalVariables = false);
>
> /// \brief Try to recover by turning the given expression into a
> /// call. Returns true if recovery was attempted or an error was
> @@ -3543,7 +3544,8 @@
> void ActOnCXXExitDeclInitializer(Scope *S, Decl *Dcl);
>
> /// \brief Create a new lambda closure type.
> - CXXRecordDecl *createLambdaClosureType(SourceRange IntroducerRange);
> + CXXRecordDecl *createLambdaClosureType(SourceRange IntroducerRange,
> + bool KnownDependent = false);
>
> /// \brief Start the definition of a lambda expression.
> CXXMethodDecl *startLambdaDefinition(CXXRecordDecl *Class,
>
> Modified: cfe/trunk/lib/AST/DeclBase.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/DeclBase.cpp?rev=151076&r1=151075&r2=151076&view=diff
> ==============================================================================
> --- cfe/trunk/lib/AST/DeclBase.cpp (original)
> +++ cfe/trunk/lib/AST/DeclBase.cpp Tue Feb 21 13:11:17 2012
> @@ -741,10 +741,14 @@
> if (isa<ClassTemplatePartialSpecializationDecl>(this))
> return true;
>
> - if (const CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(this))
> + if (const CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(this)) {
> if (Record->getDescribedClassTemplate())
> return true;
> -
> +
> + if (Record->isDependentLambda())
> + return true;
> + }
> +
> if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(this)) {
> if (Function->getDescribedFunctionTemplate())
> return true;
>
> Modified: cfe/trunk/lib/AST/DeclCXX.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/DeclCXX.cpp?rev=151076&r1=151075&r2=151076&view=diff
> ==============================================================================
> --- cfe/trunk/lib/AST/DeclCXX.cpp (original)
> +++ cfe/trunk/lib/AST/DeclCXX.cpp Tue Feb 21 13:11:17 2012
> @@ -83,11 +83,11 @@
> }
>
> CXXRecordDecl *CXXRecordDecl::CreateLambda(const ASTContext &C, DeclContext *DC,
> - SourceLocation Loc) {
> + SourceLocation Loc, bool Dependent) {
> CXXRecordDecl* R = new (C) CXXRecordDecl(CXXRecord, TTK_Class, DC, Loc, Loc,
> 0, 0);
> R->IsBeingDefined = true;
> - R->DefinitionData = new (C) struct LambdaDefinitionData(R);
> + R->DefinitionData = new (C) struct LambdaDefinitionData(R, Dependent);
> C.getTypeDeclType(R, /*PrevDecl=*/0);
> return R;
> }
>
> Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=151076&r1=151075&r2=151076&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaExpr.cpp Tue Feb 21 13:11:17 2012
> @@ -3146,7 +3146,8 @@
> // We already type-checked the argument, so we know it works.
> // Just mark all of the declarations in this potentially-evaluated expression
> // as being "referenced".
> - MarkDeclarationsReferencedInExpr(Param->getDefaultArg());
> + MarkDeclarationsReferencedInExpr(Param->getDefaultArg(),
> + /*SkipLocalVariables=*/true);
> return Owned(CXXDefaultArgExpr::Create(Context, CallLoc, Param));
> }
>
> @@ -10145,13 +10146,22 @@
> /// potentially-evaluated subexpressions as "referenced".
> class EvaluatedExprMarker : public EvaluatedExprVisitor<EvaluatedExprMarker> {
> Sema &S;
> + bool SkipLocalVariables;
>
> public:
> typedef EvaluatedExprVisitor<EvaluatedExprMarker> Inherited;
>
> - explicit EvaluatedExprMarker(Sema &S) : Inherited(S.Context), S(S) { }
> + EvaluatedExprMarker(Sema &S, bool SkipLocalVariables)
> + : Inherited(S.Context), S(S), SkipLocalVariables(SkipLocalVariables) { }
>
> void VisitDeclRefExpr(DeclRefExpr *E) {
> + // If we were asked not to visit local variables, don't.
> + if (SkipLocalVariables) {
> + if (VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
> + if (VD->hasLocalStorage())
> + return;
> + }
> +
> S.MarkDeclRefReferenced(E);
> }
>
> @@ -10193,6 +10203,10 @@
> }
>
> void VisitBlockDeclRefExpr(BlockDeclRefExpr *E) {
> + // If we were asked not to visit local variables, don't.
> + if (SkipLocalVariables && E->getDecl()->hasLocalStorage())
> + return;
What exactly are the rules for odr-use marking inside a lambda in a
default argument, actually?
-Eli
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