diff options
| author | Jason Merrill <jason@redhat.com> | 2020-05-11 14:05:46 -0400 |
|---|---|---|
| committer | Jason Merrill <jason@redhat.com> | 2020-05-11 15:10:05 -0400 |
| commit | aa2c978400f3b3ca6e9f2d18598a379589e77ba0 (patch) | |
| tree | 01a5cdae070da6abcbd646a94b31be0ab26d8761 | |
| parent | e5ccab839a24a9c5ac1ddbb6e0ad1c339df3165e (diff) | |
c++: Make references to __cxa_pure_virtual weak.
If a program has no other dependencies on libstdc++, we shouldn't require it
just for __cxa_pure_virtual, which is only there to give a prettier
diagnostic before crashing the program; resolving the reference to NULL will
also crash, just without the diagnostic.
gcc/cp/ChangeLog
2020-05-11 Jason Merrill <jason@redhat.com>
* decl.c (cxx_init_decl_processing): Call declare_weak for
__cxa_pure_virtual.
| -rw-r--r-- | gcc/cp/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/cp/decl.c | 3 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/abi/pure-virtual1.C | 21 |
3 files changed, 29 insertions, 0 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 1fdc3880fff..2cc9b8deb15 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,5 +1,10 @@ 2020-05-11 Jason Merrill <jason@redhat.com> + * decl.c (cxx_init_decl_processing): Call declare_weak for + __cxa_pure_virtual. + +2020-05-11 Jason Merrill <jason@redhat.com> + * pt.c (instantiate_class_template_1): Call tsubst_expr for STATIC_ASSERT member. * ptree.c (cxx_print_xnode): Handle STATIC_ASSERT. diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c index dea1ba07c0e..1b6a5672334 100644 --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -4544,6 +4544,9 @@ cxx_init_decl_processing (void) abort_fndecl = build_library_fn_ptr ("__cxa_pure_virtual", void_ftype, ECF_NORETURN | ECF_NOTHROW | ECF_COLD); + if (flag_weak) + /* If no definition is available, resolve references to NULL. */ + declare_weak (abort_fndecl); /* Perform other language dependent initializations. */ init_class_processing (); diff --git a/gcc/testsuite/g++.dg/abi/pure-virtual1.C b/gcc/testsuite/g++.dg/abi/pure-virtual1.C new file mode 100644 index 00000000000..823328ea951 --- /dev/null +++ b/gcc/testsuite/g++.dg/abi/pure-virtual1.C @@ -0,0 +1,21 @@ +// Test that we don't need libsupc++ just for __cxa_pure_virtual. +// { dg-do link } +// { dg-require-weak } +// { dg-additional-options "-fno-rtti -nodefaultlibs -lc" } + +struct A +{ + int i; + virtual void f() = 0; + A(): i(0) {} +}; + +struct B: A +{ + virtual void f() {} +}; + +int main() +{ + B b; +} |