yronglin marked 2 inline comments as done. yronglin added inline comments.
================ Comment at: clang/lib/Sema/SemaExprCXX.cpp:8901-8914 + // [P2718R0] Lifetime extension in range-based for loops. + // + // 6.7.7 [class.temporary] p5: + // There are four contexts in which temporaries are destroyed at a different + // point than the end of the full-expression. + // + // 6.7.7 [class.temporary] p6: ---------------- hubert.reinterpretcast wrote: > yronglin wrote: > > rsmith wrote: > > > This isn't the right way to model the behavior here -- the presence or > > > absence of an `ExprWithCleanups` is just a convenience to tell consumers > > > of the AST whether they should expect to see cleanups later or not, and > > > doesn't carry an implication of affecting the actual temporary lifetimes > > > and storage durations. > > > > > > The outcome that we should be aiming to reach is that all > > > `MaterializeTemporaryExpr`s created as part of processing the > > > for-range-initializer are marked as being lifetime-extended by the > > > for-range variable. Probably the simplest way to handle that would be to > > > track the current enclosing for-range-initializer variable in the > > > `ExpressionEvaluationContextRecord`, and whenever a > > > `MaterializeTemporaryExpr` is created, if there is a current enclosing > > > for-range-initializer, mark that `MaterializeTemporaryExpr` as being > > > lifetime-extended by it. > > Awesome! Thanks a lot for your advice, this is very helpful! I want to take > > a longer look at it. > As mentioned in D139586, `CXXDefaultArgExpr`s may need additional handling. > Similarly for `CXXDefaultInitExpr`s. Thanks for your tips! I have a question that what's the correct way to extent the lifetime of `CXXBindTemporaryExpr`? Can I just `materialize` the temporary? It may replaced by `MaterializeTemporaryExpr`, and then I can mark it as being lifetime-extended by the for-range variable. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D153701/new/ https://reviews.llvm.org/D153701 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
