| Message ID | 672f1d48.170a0220.4887.9d62@mx.google.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/3] c++: Fix mangling of otherwise unattached class-scope lambdas [PR107741] | expand |
On 11/9/24 9:28 AM, Nathaniel Shead wrote: > Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk? OK. > Alternatively, after this I'll work on an update of my P1815 (TU-local > entities) patch series [1] which would also solve this ICE by erroring > early due to attempting to emit a TU-local entity. As discussed in > patch #1 I believe this is incorrect but also seems out of scope of this > particular modification. I still think this patch would be useful > however, if only for the clarification of the behaviour of streaming > lambdas without an extra mangling scope. > > [1]: https://gcc.gnu.org/pipermail/gcc-patches/2024-October/665108.html > > -- >8 -- > > If a lambda doesn't have an extra mangling scope despite being in class > scope (such as associated with a type alias, currently), we shouldn't > ICE; this behaviour is fine as long as we don't need to merge. > > In the future such lambdas should be rejected as being TU-local, but for > now this at least clarifies the intended behaviour if this edge case > occurs again. > > PR c++/116568 > > gcc/cp/ChangeLog: > > * module.cc (trees_out::get_merge_kind): All lambdas without > extra mangling scope now marked MK_unique. > > gcc/testsuite/ChangeLog: > > * g++.dg/modules/lambda-8.h: New test. > * g++.dg/modules/lambda-8_a.H: New test. > * g++.dg/modules/lambda-8_b.C: New test. > > Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com> > --- > gcc/cp/module.cc | 30 ++++++++++++++--------- > gcc/testsuite/g++.dg/modules/lambda-8.h | 7 ++++++ > gcc/testsuite/g++.dg/modules/lambda-8_a.H | 5 ++++ > gcc/testsuite/g++.dg/modules/lambda-8_b.C | 5 ++++ > 4 files changed, 35 insertions(+), 12 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/modules/lambda-8.h > create mode 100644 gcc/testsuite/g++.dg/modules/lambda-8_a.H > create mode 100644 gcc/testsuite/g++.dg/modules/lambda-8_b.C > > diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc > index 4eefb2d3584..877e442bc41 100644 > --- a/gcc/cp/module.cc > +++ b/gcc/cp/module.cc > @@ -10737,18 +10737,24 @@ trees_out::get_merge_kind (tree decl, depset *dep) > g++.dg/modules/lambda-6_a.C. */ > if (DECL_IMPLICIT_TYPEDEF_P (STRIP_TEMPLATE (decl)) > && LAMBDA_TYPE_P (TREE_TYPE (decl))) > - if (tree scope = LAMBDA_TYPE_EXTRA_SCOPE (TREE_TYPE (decl))) > - { > - /* Lambdas attached to fields are keyed to its class. */ > - if (TREE_CODE (scope) == FIELD_DECL) > - scope = TYPE_NAME (DECL_CONTEXT (scope)); > - if (DECL_LANG_SPECIFIC (scope) > - && DECL_MODULE_KEYED_DECLS_P (scope)) > - { > - mk = MK_keyed; > - break; > - } > - } > + { > + if (tree scope = LAMBDA_TYPE_EXTRA_SCOPE (TREE_TYPE (decl))) > + { > + /* Lambdas attached to fields are keyed to its class. */ > + if (TREE_CODE (scope) == FIELD_DECL) > + scope = TYPE_NAME (DECL_CONTEXT (scope)); > + if (DECL_LANG_SPECIFIC (scope) > + && DECL_MODULE_KEYED_DECLS_P (scope)) > + { > + mk = MK_keyed; > + break; > + } > + } > + /* Lambdas without extra mangling scope are unique to the TU, > + and cannot be merged; make them unique. */ > + mk = MK_unique; > + break; > + } > > if (TREE_CODE (decl) == TEMPLATE_DECL > && DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P (decl)) > diff --git a/gcc/testsuite/g++.dg/modules/lambda-8.h b/gcc/testsuite/g++.dg/modules/lambda-8.h > new file mode 100644 > index 00000000000..0c66f053b20 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/modules/lambda-8.h > @@ -0,0 +1,7 @@ > +template <typename> struct S { > + template <typename> static constexpr auto x = []{}; > + template <typename> using t = decltype([]{}); > +}; > + > +inline auto x = S<int>::x<int>; > +using t = S<int>::t<int>; > diff --git a/gcc/testsuite/g++.dg/modules/lambda-8_a.H b/gcc/testsuite/g++.dg/modules/lambda-8_a.H > new file mode 100644 > index 00000000000..d20958ee140 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/modules/lambda-8_a.H > @@ -0,0 +1,5 @@ > +// PR c++/116568 > +// { dg-additional-options "-fmodules-ts -std=c++20" } > +// { dg-module-cmi {} } > + > +#include "lambda-8.h" > diff --git a/gcc/testsuite/g++.dg/modules/lambda-8_b.C b/gcc/testsuite/g++.dg/modules/lambda-8_b.C > new file mode 100644 > index 00000000000..05ea4afd8c1 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/modules/lambda-8_b.C > @@ -0,0 +1,5 @@ > +// PR c++/116568 > +// { dg-additional-options "-fmodules-ts -std=c++20" } > + > +#include "lambda-8.h" > +import "lambda-8_a.H";
diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc index 4eefb2d3584..877e442bc41 100644 --- a/gcc/cp/module.cc +++ b/gcc/cp/module.cc @@ -10737,18 +10737,24 @@ trees_out::get_merge_kind (tree decl, depset *dep) g++.dg/modules/lambda-6_a.C. */ if (DECL_IMPLICIT_TYPEDEF_P (STRIP_TEMPLATE (decl)) && LAMBDA_TYPE_P (TREE_TYPE (decl))) - if (tree scope = LAMBDA_TYPE_EXTRA_SCOPE (TREE_TYPE (decl))) - { - /* Lambdas attached to fields are keyed to its class. */ - if (TREE_CODE (scope) == FIELD_DECL) - scope = TYPE_NAME (DECL_CONTEXT (scope)); - if (DECL_LANG_SPECIFIC (scope) - && DECL_MODULE_KEYED_DECLS_P (scope)) - { - mk = MK_keyed; - break; - } - } + { + if (tree scope = LAMBDA_TYPE_EXTRA_SCOPE (TREE_TYPE (decl))) + { + /* Lambdas attached to fields are keyed to its class. */ + if (TREE_CODE (scope) == FIELD_DECL) + scope = TYPE_NAME (DECL_CONTEXT (scope)); + if (DECL_LANG_SPECIFIC (scope) + && DECL_MODULE_KEYED_DECLS_P (scope)) + { + mk = MK_keyed; + break; + } + } + /* Lambdas without extra mangling scope are unique to the TU, + and cannot be merged; make them unique. */ + mk = MK_unique; + break; + } if (TREE_CODE (decl) == TEMPLATE_DECL && DECL_UNINSTANTIATED_TEMPLATE_FRIEND_P (decl)) diff --git a/gcc/testsuite/g++.dg/modules/lambda-8.h b/gcc/testsuite/g++.dg/modules/lambda-8.h new file mode 100644 index 00000000000..0c66f053b20 --- /dev/null +++ b/gcc/testsuite/g++.dg/modules/lambda-8.h @@ -0,0 +1,7 @@ +template <typename> struct S { + template <typename> static constexpr auto x = []{}; + template <typename> using t = decltype([]{}); +}; + +inline auto x = S<int>::x<int>; +using t = S<int>::t<int>; diff --git a/gcc/testsuite/g++.dg/modules/lambda-8_a.H b/gcc/testsuite/g++.dg/modules/lambda-8_a.H new file mode 100644 index 00000000000..d20958ee140 --- /dev/null +++ b/gcc/testsuite/g++.dg/modules/lambda-8_a.H @@ -0,0 +1,5 @@ +// PR c++/116568 +// { dg-additional-options "-fmodules-ts -std=c++20" } +// { dg-module-cmi {} } + +#include "lambda-8.h" diff --git a/gcc/testsuite/g++.dg/modules/lambda-8_b.C b/gcc/testsuite/g++.dg/modules/lambda-8_b.C new file mode 100644 index 00000000000..05ea4afd8c1 --- /dev/null +++ b/gcc/testsuite/g++.dg/modules/lambda-8_b.C @@ -0,0 +1,5 @@ +// PR c++/116568 +// { dg-additional-options "-fmodules-ts -std=c++20" } + +#include "lambda-8.h" +import "lambda-8_a.H";
Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk? Alternatively, after this I'll work on an update of my P1815 (TU-local entities) patch series [1] which would also solve this ICE by erroring early due to attempting to emit a TU-local entity. As discussed in patch #1 I believe this is incorrect but also seems out of scope of this particular modification. I still think this patch would be useful however, if only for the clarification of the behaviour of streaming lambdas without an extra mangling scope. [1]: https://gcc.gnu.org/pipermail/gcc-patches/2024-October/665108.html -- >8 -- If a lambda doesn't have an extra mangling scope despite being in class scope (such as associated with a type alias, currently), we shouldn't ICE; this behaviour is fine as long as we don't need to merge. In the future such lambdas should be rejected as being TU-local, but for now this at least clarifies the intended behaviour if this edge case occurs again. PR c++/116568 gcc/cp/ChangeLog: * module.cc (trees_out::get_merge_kind): All lambdas without extra mangling scope now marked MK_unique. gcc/testsuite/ChangeLog: * g++.dg/modules/lambda-8.h: New test. * g++.dg/modules/lambda-8_a.H: New test. * g++.dg/modules/lambda-8_b.C: New test. Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com> --- gcc/cp/module.cc | 30 ++++++++++++++--------- gcc/testsuite/g++.dg/modules/lambda-8.h | 7 ++++++ gcc/testsuite/g++.dg/modules/lambda-8_a.H | 5 ++++ gcc/testsuite/g++.dg/modules/lambda-8_b.C | 5 ++++ 4 files changed, 35 insertions(+), 12 deletions(-) create mode 100644 gcc/testsuite/g++.dg/modules/lambda-8.h create mode 100644 gcc/testsuite/g++.dg/modules/lambda-8_a.H create mode 100644 gcc/testsuite/g++.dg/modules/lambda-8_b.C