| Message ID | 27d0753f-39f8-b80b-d92d-86ce7163ea23@oracle.com |
|---|---|
| State | New |
| Headers | show |
| Series | [C++] PR 89488 ("[9 Regression] ICE in merge_exception_specifiers, at cp/typeck2.c:2395") | expand |
On 2/25/19 10:27 AM, Paolo Carlini wrote: > Hi, > > this error recovery regression has to do with the recent changes > committed by Jason for c++/88368. What happens is that > maybe_instantiate_noexcept fails the hard way, thus, toward the end of > the function, doesn't update TREE_TYPE (fn) and just returns false. > process_subob_fn doesn't notice and proceeds to call > merge_exception_specifiers anyway where of course the gcc_assert > (!DEFERRED_NOEXCEPT_SPEC_P (add)) triggers, because > maybe_instantiate_noexcept has not done its normal job. To improve > error-recovery I think we can simply leave *spec_p alone in such cases, > because we would merge the *spec_p with a TYPE_RAISES_EXCEPTIONS > (TREE_TYPE (fn)) where TREE_TYPE (fn) has not been normally computed. I > tried a few other things which prima facie looked sensible but nothing > else worked - eg, returning false from maybe_instantiate_noexcept and > also updating TREE_TYPE (fn) to a noexcept_false_spec variant causes > regressions exactly for the testcases of c++/88368. If maybe_instantiate_noexcept returns false, I think we should set *spec_p to error_mark_node. Jason
Hi, On 26/02/19 15:28, Jason Merrill wrote: > On 2/25/19 10:27 AM, Paolo Carlini wrote: >> Hi, >> >> this error recovery regression has to do with the recent changes >> committed by Jason for c++/88368. What happens is that >> maybe_instantiate_noexcept fails the hard way, thus, toward the end >> of the function, doesn't update TREE_TYPE (fn) and just returns >> false. process_subob_fn doesn't notice and proceeds to call >> merge_exception_specifiers anyway where of course the gcc_assert >> (!DEFERRED_NOEXCEPT_SPEC_P (add)) triggers, because >> maybe_instantiate_noexcept has not done its normal job. To improve >> error-recovery I think we can simply leave *spec_p alone in such >> cases, because we would merge the *spec_p with a >> TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn)) where TREE_TYPE (fn) has not >> been normally computed. I tried a few other things which prima facie >> looked sensible but nothing else worked - eg, returning false from >> maybe_instantiate_noexcept and also updating TREE_TYPE (fn) to a >> noexcept_false_spec variant causes regressions exactly for the >> testcases of c++/88368. > > If maybe_instantiate_noexcept returns false, I think we should set > *spec_p to error_mark_node. Sure, that certainly works, I tested it a couple of days ago and I'm finishing testing the below now. The only difference is that during error-recovery 'zl ()' is seen as seriously broken and we don't give the second, "cannot convert", error message, which we used to give. Thanks, Paolo. ///////////////////// Index: cp/method.c =================================================================== --- cp/method.c (revision 269187) +++ cp/method.c (working copy) @@ -1256,9 +1256,13 @@ process_subob_fn (tree fn, tree *spec_p, bool *tri if (spec_p) { - maybe_instantiate_noexcept (fn); - tree raises = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn)); - *spec_p = merge_exception_specifiers (*spec_p, raises); + if (!maybe_instantiate_noexcept (fn)) + *spec_p = error_mark_node; + else + { + tree raises = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn)); + *spec_p = merge_exception_specifiers (*spec_p, raises); + } } if (!trivial_fn_p (fn) && !dtor_from_ctor) Index: testsuite/g++.dg/cpp0x/nsdmi15.C =================================================================== --- testsuite/g++.dg/cpp0x/nsdmi15.C (nonexistent) +++ testsuite/g++.dg/cpp0x/nsdmi15.C (working copy) @@ -0,0 +1,8 @@ +// PR c++/89488 +// { dg-do compile { target c++11 } } + +struct zl { + struct { + int x2 = zl (); // { dg-error "default member" } + } fx; +};
On 2/26/19 11:02 AM, Paolo Carlini wrote: > Hi, > > On 26/02/19 15:28, Jason Merrill wrote: >> On 2/25/19 10:27 AM, Paolo Carlini wrote: >>> Hi, >>> >>> this error recovery regression has to do with the recent changes >>> committed by Jason for c++/88368. What happens is that >>> maybe_instantiate_noexcept fails the hard way, thus, toward the end >>> of the function, doesn't update TREE_TYPE (fn) and just returns >>> false. process_subob_fn doesn't notice and proceeds to call >>> merge_exception_specifiers anyway where of course the gcc_assert >>> (!DEFERRED_NOEXCEPT_SPEC_P (add)) triggers, because >>> maybe_instantiate_noexcept has not done its normal job. To improve >>> error-recovery I think we can simply leave *spec_p alone in such >>> cases, because we would merge the *spec_p with a >>> TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn)) where TREE_TYPE (fn) has not >>> been normally computed. I tried a few other things which prima facie >>> looked sensible but nothing else worked - eg, returning false from >>> maybe_instantiate_noexcept and also updating TREE_TYPE (fn) to a >>> noexcept_false_spec variant causes regressions exactly for the >>> testcases of c++/88368. >> >> If maybe_instantiate_noexcept returns false, I think we should set >> *spec_p to error_mark_node. > > Sure, that certainly works, I tested it a couple of days ago and I'm > finishing testing the below now. The only difference is that during > error-recovery 'zl ()' is seen as seriously broken and we don't give the > second, "cannot convert", error message, which we used to give. OK if it passes. Jason
Index: cp/method.c =================================================================== --- cp/method.c (revision 269187) +++ cp/method.c (working copy) @@ -1254,9 +1254,8 @@ process_subob_fn (tree fn, tree *spec_p, bool *tri return; } - if (spec_p) + if (spec_p && maybe_instantiate_noexcept (fn)) { - maybe_instantiate_noexcept (fn); tree raises = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn)); *spec_p = merge_exception_specifiers (*spec_p, raises); } Index: testsuite/g++.dg/cpp0x/nsdmi15.C =================================================================== --- testsuite/g++.dg/cpp0x/nsdmi15.C (nonexistent) +++ testsuite/g++.dg/cpp0x/nsdmi15.C (working copy) @@ -0,0 +1,8 @@ +// PR c++/89488 +// { dg-do compile { target c++11 } } + +struct zl { + struct { + int x2 = zl (); // { dg-error "default member|cannot convert" } + } fx; +};