[clang] bdad0a1 - PR45083: Mark statement expressions as being dependent if they appear in
Hans Wennborg via cfe-commits
cfe-commits at lists.llvm.org
Wed Mar 4 00:30:39 PST 2020
Pushed to 10.x as 3a843031a5ad83a00d2603f623881cb2b2bf719d. Please let
me know if you hear about any follow-up issues.
Thanks!
On Wed, Mar 4, 2020 at 12:28 AM Richard Smith via cfe-commits
<cfe-commits at lists.llvm.org> wrote:
>
>
> Author: Richard Smith
> Date: 2020-03-03T15:20:40-08:00
> New Revision: bdad0a1b79273733df9acc1be4e992fa5d70ec56
>
> URL: https://github.com/llvm/llvm-project/commit/bdad0a1b79273733df9acc1be4e992fa5d70ec56
> DIFF: https://github.com/llvm/llvm-project/commit/bdad0a1b79273733df9acc1be4e992fa5d70ec56.diff
>
> LOG: 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.
>
> Added:
>
>
> Modified:
> clang/include/clang/AST/Expr.h
> clang/include/clang/Sema/Sema.h
> clang/lib/AST/ASTImporter.cpp
> clang/lib/Parse/ParseExpr.cpp
> clang/lib/Sema/SemaExpr.cpp
> clang/lib/Sema/SemaExprCXX.cpp
> clang/lib/Sema/TreeTransform.h
> clang/test/SemaTemplate/dependent-expr.cpp
>
> Removed:
>
>
>
> ################################################################################
> diff --git a/clang/include/clang/AST/Expr.h b/clang/include/clang/AST/Expr.h
> index fcdb0b992134..87f9b883486a 100644
> --- a/clang/include/clang/AST/Expr.h
> +++ b/clang/include/clang/AST/Expr.h
> @@ -3960,14 +3960,14 @@ class StmtExpr : public Expr {
> Stmt *SubStmt;
> SourceLocation LParenLoc, RParenLoc;
> public:
> - // FIXME: Does type-dependence need to be computed
> diff erently?
> - // 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),
> - SubStmt(substmt), LParenLoc(lp), RParenLoc(rp) { }
> + T->isDependentType(), InDependentContext, InDependentContext, false),
> + SubStmt(substmt), LParenLoc(lp), RParenLoc(rp) {}
>
> /// Build an empty statement expression.
> explicit StmtExpr(EmptyShell Empty) : Expr(StmtExprClass, Empty) { }
>
> diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
> index 2304a9718567..5739808753e3 100644
> --- a/clang/include/clang/Sema/Sema.h
> +++ b/clang/include/clang/Sema/Sema.h
> @@ -4964,7 +4964,7 @@ class Sema final {
> 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);
>
> diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
> index 52288318337d..0cf00f6ca15b 100644
> --- a/clang/lib/AST/ASTImporter.cpp
> +++ b/clang/lib/AST/ASTImporter.cpp
> @@ -6631,8 +6631,9 @@ ExpectedStmt ASTNodeImporter::VisitStmtExpr(StmtExpr *E) {
> if (Err)
> return std::move(Err);
>
> - 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) {
>
> diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
> index 584de6b87d90..b038e6935d87 100644
> --- a/clang/lib/Parse/ParseExpr.cpp
> +++ b/clang/lib/Parse/ParseExpr.cpp
> @@ -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();
> }
>
> diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
> index f50a77a40510..1870e440199d 100644
> --- a/clang/lib/Sema/SemaExpr.cpp
> +++ b/clang/lib/Sema/SemaExpr.cpp
> @@ -13911,9 +13911,8 @@ void Sema::ActOnStmtExprError() {
> PopExpressionEvaluationContext();
> }
>
> -ExprResult
> -Sema::ActOnStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
> - SourceLocation RPLoc) { // "({..})"
> +ExprResult Sema::ActOnStmtExpr(Scope *S, SourceLocation LPLoc, Stmt *SubStmt,
> + SourceLocation RPLoc) { // "({..})"
> assert(SubStmt && isa<CompoundStmt>(SubStmt) && "Invalid action invocation!");
> CompoundStmt *Compound = cast<CompoundStmt>(SubStmt);
>
> @@ -13942,9 +13941,18 @@ 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;
>
> diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
> index c8c6d7c95a7f..e521ba1d4af1 100644
> --- a/clang/lib/Sema/SemaExprCXX.cpp
> +++ b/clang/lib/Sema/SemaExprCXX.cpp
> @@ -6955,8 +6955,9 @@ Stmt *Sema::MaybeCreateStmtWithCleanups(Stmt *SubStmt) {
> // a new AsmStmtWithTemporaries.
> CompoundStmt *CompStmt = CompoundStmt::Create(
> Context, SubStmt, SourceLocation(), SourceLocation());
> - Expr *E = new (Context) StmtExpr(CompStmt, Context.VoidTy, SourceLocation(),
> - SourceLocation());
> + Expr *E = new (Context)
> + StmtExpr(CompStmt, Context.VoidTy, SourceLocation(), SourceLocation(),
> + CurContext->isDependentContext());
> return MaybeCreateExprWithCleanups(E);
> }
>
>
> diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
> index 002b73c3a1dd..05b41aa53da6 100644
> --- a/clang/lib/Sema/TreeTransform.h
> +++ b/clang/lib/Sema/TreeTransform.h
> @@ -2549,10 +2549,9 @@ class TreeTransform {
> ///
> /// By default, performs semantic analysis to build the new expression.
> /// Subclasses may override this routine to provide
> diff erent behavior.
> - ExprResult RebuildStmtExpr(SourceLocation LParenLoc,
> - Stmt *SubStmt,
> - SourceLocation RParenLoc) {
> - return getSema().ActOnStmtExpr(LParenLoc, SubStmt, RParenLoc);
> + ExprResult RebuildStmtExpr(SourceLocation LParenLoc, Stmt *SubStmt,
> + SourceLocation RParenLoc) {
> + return getSema().ActOnStmtExpr(nullptr, LParenLoc, SubStmt, RParenLoc);
> }
>
> /// Build a new __builtin_choose_expr expression.
> @@ -11888,6 +11887,8 @@ TreeTransform<Derived>::TransformLambdaExpr(LambdaExpr *E) {
> NewTrailingRequiresClause = getDerived().TransformExpr(TRC);
>
> // Create the local class that will describe the lambda.
> + // FIXME: KnownDependent below is wrong when substituting inside a templated
> + // context that isn't a DeclContext (such as a variable template).
> CXXRecordDecl *OldClass = E->getLambdaClass();
> CXXRecordDecl *Class
> = getSema().createLambdaClosureType(E->getIntroducerRange(),
>
> diff --git a/clang/test/SemaTemplate/dependent-expr.cpp b/clang/test/SemaTemplate/dependent-expr.cpp
> index bb1e239c3490..e333ed927b9e 100644
> --- a/clang/test/SemaTemplate/dependent-expr.cpp
> +++ b/clang/test/SemaTemplate/dependent-expr.cpp
> @@ -1,5 +1,4 @@
> // RUN: %clang_cc1 -fsyntax-only -verify %s
> -// expected-no-diagnostics
>
> // PR5908
> template <typename Iterator>
> @@ -108,3 +107,22 @@ namespace PR18152 {
> };
> template struct A<0>;
> }
> +
> +template<typename T> void stmt_expr_1() {
> + static_assert( ({ false; }), "" );
> +}
> +void stmt_expr_2() {
> + static_assert( ({ false; }), "" ); // expected-error {{failed}}
> +}
> +
> +namespace PR45083 {
> + struct A { bool x; };
> +
> + template<typename> struct B : A {
> + void f() {
> + const int n = ({ if (x) {} 0; });
> + }
> + };
> +
> + template void B<int>::f();
> +}
>
>
>
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