From: Marek Polacek Date: Tue, 12 Jan 2021 21:16:44 +0000 (-0500) Subject: c++: ICE with delayed noexcept and attribute used [PR97966] X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=bca467e56fe111fa6d876656c60d5704065e83fe;p=gcc.git c++: ICE with delayed noexcept and attribute used [PR97966] Another ICE with delayed noexcept parsing, but a bit gnarlier. A function definition marked with __attribute__((used)) ought to be emitted even when it is not referenced in the TU. For a member function template marked with __attribute__((used)) this means that it will be instantiated: in instantiate_class_template_1 we have 11971 /* Instantiate members marked with attribute used. */ 11972 if (r != error_mark_node && DECL_PRESERVE_P (r)) 11973 mark_used (r); It is not so surprising that this doesn't work well with delayed noexcept parsing: when we're processing the function template we delay the parsing, so the member "foo" is found, but then when we're instantiating it, "foo" hasn't yet been seen, which creates a discrepancy and a crash ensues. "foo" hasn't yet been seen because instantiate_class_template_1 just loops over the class members and instantiates right away. To make it work, this patch uses a vector to keep track of members marked with attribute used and uses it to instantiate such members only after we're done with the class; in particular, after we have called finish_member_declaration for each member. And we ought to be verifying that we did emit such members, so I've added a bunch of dg-finals. gcc/cp/ChangeLog: PR c++/97966 * pt.c (instantiate_class_template_1): Instantiate members marked with attribute used only after we're done instantiating the class. gcc/testsuite/ChangeLog: PR c++/97966 * g++.dg/cpp0x/noexcept63.C: New test. --- diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index 373f8279604..63a0a110440 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -11895,6 +11895,9 @@ instantiate_class_template_1 (tree type) relative to the scope of the class. */ pop_to_parent_deferring_access_checks (); + /* A vector to hold members marked with attribute used. */ + auto_vec used; + /* Now members are processed in the order of declaration. */ for (member = CLASSTYPE_DECL_LIST (pattern); member; member = TREE_CHAIN (member)) @@ -11968,7 +11971,7 @@ instantiate_class_template_1 (tree type) finish_member_declaration (r); /* Instantiate members marked with attribute used. */ if (r != error_mark_node && DECL_PRESERVE_P (r)) - mark_used (r); + used.safe_push (r); if (TREE_CODE (r) == FUNCTION_DECL && DECL_OMP_DECLARE_REDUCTION_P (r)) cp_check_omp_declare_reduction (r); @@ -12034,7 +12037,7 @@ instantiate_class_template_1 (tree type) /*flags=*/0); /* Instantiate members marked with attribute used. */ if (r != error_mark_node && DECL_PRESERVE_P (r)) - mark_used (r); + used.safe_push (r); } else if (TREE_CODE (r) == FIELD_DECL) { @@ -12225,6 +12228,11 @@ instantiate_class_template_1 (tree type) if (TYPE_CONTAINS_VPTR_P (type) && CLASSTYPE_KEY_METHOD (type)) vec_safe_push (keyed_classes, type); + /* Now that we've gone through all the members, instantiate those + marked with attribute used. */ + for (tree x : used) + mark_used (x); + return type; } diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept63.C b/gcc/testsuite/g++.dg/cpp0x/noexcept63.C new file mode 100644 index 00000000000..cf048f56c2a --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept63.C @@ -0,0 +1,63 @@ +// PR c++/97966 +// { dg-do compile { target c++11 } } + +template +struct S1 { + __attribute__((used)) S1() noexcept(noexcept(this->foo())) { } + void foo(); +}; + +template +struct S2 { + __attribute__((used)) void bar() noexcept(noexcept(this->foo())) { } + void foo(); +}; + +template +struct S3 { + void __attribute__((used)) bar() noexcept(noexcept(this->foo())) { } + void foo(); +}; + +template +struct S4 { + [[gnu::used]] void bar() noexcept(noexcept(this->foo())) { } + void foo(); +}; + +template +struct S5 { + void bar() noexcept(noexcept(this->foo())) __attribute__((used)) { } + void foo(); +}; + +template +struct S6 { + template + struct N { + [[gnu::used]] void bar() noexcept(noexcept(this->foo())) { } + void foo(); + }; +}; + +void +g () +{ + S1<1> s1; + S2<1> s2; + S3<1> s3; + S4<1> s4; + S5<1> s5; + S6<1>::N<1> n; +} + +// Make sure that we did emit the functions marked with attribute used +// even though they're not referenced in this TU. (Well, the S1() +// constructor is.) +// { dg-final { scan-assembler "_ZN2S1ILi1EEC1Ev" } } +// { dg-final { scan-assembler "_ZN2S1ILi1EEC2Ev" } } +// { dg-final { scan-assembler "_ZN2S2ILi1EE3barEv" } } +// { dg-final { scan-assembler "_ZN2S3ILi1EE3barEv" } } +// { dg-final { scan-assembler "_ZN2S4ILi1EE3barEv" } } +// { dg-final { scan-assembler "_ZN2S5ILi1EE3barEv" } } +// { dg-final { scan-assembler "_ZN2S6ILi1EE1NILi1EE3barEv" } }