[clang] bdad0a1 - PR45083: Mark statement expressions as being dependent if they appear in
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Thu Mar 5 12:20:11 PST 2020
On Thu, 5 Mar 2020 at 06:13, Benjamin Kramer via cfe-commits <
cfe-commits at lists.llvm.org> wrote:
> creduce produced this. It's a crash on invalid, but was created from a
> valid input.
>
Well, "valid" is unclear when using language extensions, but OK.
> $ cat r.ii
> template <class a> auto b(a) {
> auto c = [](auto, int) -> decltype(({})) {};
> return c(0, 0);
> }
> using d = decltype(b(0));
> bool f = d ::e;
>
How important is this testcase? The fix you reverted was fixing a
release-blocker; is this also a release-blocker in your view?
> $ clang r.ii -std=c++17 -w
> clang-11: clang/lib/AST/Decl.cpp:2343: clang::APValue
> *clang::VarDecl::evaluateValue(SmallVectorImpl<clang::PartialDiagnosticAt>
> &) const: Assertion `!Init->isValueDependent()' failed.
>
> On Thu, Mar 5, 2020 at 2:18 PM Benjamin Kramer <benny.kra at gmail.com>
> wrote:
> >
> > It's still crashing clang, reverted this and
> > f545ede91c9d9f271e7504282cab7bf509607ead in 66addf8e8036. c-reduce is
> > still chewing on the reproducer.
> >
> > On Wed, Mar 4, 2020 at 10:20 PM Richard Smith via cfe-commits
> > <cfe-commits at lists.llvm.org> wrote:
> > >
> > > We found a regression introduced by this patch; fixed in
> f545ede91c9d9f271e7504282cab7bf509607ead.
> > >
> > > On Wed, 4 Mar 2020 at 00:30, Hans Wennborg via cfe-commits <
> cfe-commits at lists.llvm.org> wrote:
> > >>
> > >> 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();
> > >> > +}
> > >> >
> > >> >
> > >> >
> > >> > _______________________________________________
> > >> > cfe-commits mailing list
> > >> > cfe-commits at lists.llvm.org
> > >> > https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
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> > >
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