Commit 3a843031 authored by Richard Smith's avatar Richard Smith Committed by Hans Wennborg
Browse files

PR45083: Mark statement expressions as being dependent if they appear in 

dependent contexts.

We previously assumed they were neither value- nor
instantiation-dependent under any circumstances, which would lead to
crashes and other misbehavior.

(cherry picked from commit bdad0a1b)
parent bca373f7

clang/include/clang/AST/Expr.h

+6 −6
Original line number Diff line number Diff line
@@ -3955,13 +3955,13 @@ class StmtExpr : public Expr { 
  Stmt *SubStmt;

  SourceLocation LParenLoc, RParenLoc;

public:

  // FIXME: Does type-dependence need to be computed differently?

  // FIXME: Do we need to compute instantiation instantiation-dependence for

  // statements? (ugh!)

  StmtExpr(CompoundStmt *substmt, QualType T,

           SourceLocation lp, SourceLocation rp) :

           SourceLocation lp, SourceLocation rp, bool InDependentContext) :

    // Note: we treat a statement-expression in a dependent context as always

    // being value- and instantiation-dependent. This matches the behavior of

    // lambda-expressions and GCC.

    Expr(StmtExprClass, T, VK_RValue, OK_Ordinary,

         T->isDependentType(), false, false, false),

         T->isDependentType(), InDependentContext, InDependentContext, false),

    SubStmt(substmt), LParenLoc(lp), RParenLoc(rp) {}



  /// Build an empty statement expression.

clang/include/clang/Sema/Sema.h

+1 −1
Original line number Diff line number Diff line
@@ -4923,7 +4923,7 @@ public: 
                            LabelDecl *TheDecl);















  void ActOnStartStmtExpr();













  ExprResult ActOnStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,













  ExprResult ActOnStmtExpr(Scope *S, SourceLocation LPLoc, Stmt *SubStmt,















                           SourceLocation RPLoc); // "({..})"















  // Handle the final expression in a statement expression.















  ExprResult ActOnStmtExprResult(ExprResult E);

































clang/lib/AST/ASTImporter.cpp



+3
−2






























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@@ -6724,8 +6724,9 @@ ExpectedStmt ASTNodeImporter::VisitStmtExpr(StmtExpr *E) {













  SourceLocation ToLParenLoc, ToRParenLoc;















  std::tie(ToSubStmt, ToType, ToLParenLoc, ToRParenLoc) = *Imp;





























  return new (Importer.getToContext()) StmtExpr(













      ToSubStmt, ToType, ToLParenLoc, ToRParenLoc);













  return new (Importer.getToContext())













      StmtExpr(ToSubStmt, ToType, ToLParenLoc, ToRParenLoc,













               E->isInstantiationDependent());















}































ExpectedStmt ASTNodeImporter::VisitUnaryOperator(UnaryOperator *E) {

































clang/lib/Parse/ParseExpr.cpp



+2
−1






























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@@ -2655,7 +2655,8 @@ Parser::ParseParenExpression(ParenParseOption &ExprType, bool stopIfCastExpr,





























      // If the substmt parsed correctly, build the AST node.















      if (!Stmt.isInvalid()) {













        Result = Actions.ActOnStmtExpr(OpenLoc, Stmt.get(), Tok.getLocation());













        Result = Actions.ActOnStmtExpr(getCurScope(), OpenLoc, Stmt.get(),













                                       Tok.getLocation());















      } else {















        Actions.ActOnStmtExprError();















      }

































clang/lib/Sema/SemaExpr.cpp



+12
−4






























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@@ -13908,8 +13908,7 @@ void Sema::ActOnStmtExprError() {













  PopExpressionEvaluationContext();















}



























ExprResult













Sema::ActOnStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,













ExprResult Sema::ActOnStmtExpr(Scope *S, SourceLocation LPLoc, Stmt *SubStmt,















                               SourceLocation RPLoc) { // "({..})"















  assert(SubStmt && isa<CompoundStmt>(SubStmt) && "Invalid action invocation!");















  CompoundStmt *Compound = cast<CompoundStmt>(SubStmt);










@@ -13939,9 +13938,18 @@ Sema::ActOnStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,













    }















  }



























  bool IsDependentContext = false;













  if (S)













    IsDependentContext = S->getTemplateParamParent() != nullptr;













  else













    // FIXME: This is not correct when substituting inside a templated













    // context that isn't a DeclContext (such as a variable template).













    IsDependentContext = CurContext->isDependentContext();



























  // FIXME: Check that expression type is complete/non-abstract; statement















  // expressions are not lvalues.













  Expr *ResStmtExpr = new (Context) StmtExpr(Compound, Ty, LPLoc, RPLoc);













  Expr *ResStmtExpr =













      new (Context) StmtExpr(Compound, Ty, LPLoc, RPLoc, IsDependentContext);















  if (StmtExprMayBindToTemp)















    return MaybeBindToTemporary(ResStmtExpr);















  return ResStmtExpr;