Open Theodor opened 7 years ago
g++ on Solaris has special mangling twist that makes it generate non-standard mangling for std::tm, std::div_t, std::ldiv_t, std::lconv types.
W/o this twist clang fails to link with libstdc++ on testcases like this:
] cat no-tm.cc
struct D : std::time_get {};
int main() { D var; var.date_order(); } ] clang no-tm.cc Undefined first referenced symbol in file _ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE11do_get_timeES3_S3_RSt8ios_baseRSt12_Ios_IostatePSt2tm /var/tmp/no-tm-e5c67b.o _ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE11do_get_dateES3_S3_RSt8ios_baseRSt12_Ios_IostatePSt2tm /var/tmp/no-tm-e5c67b.o _ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE14do_get_weekdayES3_S3_RSt8ios_baseRSt12_Ios_IostatePSt2tm /var/tmp/no-tm-e5c67b.o _ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE11do_get_yearES3_S3_RSt8ios_baseRSt12_Ios_IostatePSt2tm /var/tmp/no-tm-e5c67b.o _ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE16do_get_monthnameES3_S3_RSt8ios_baseRSt12_Ios_IostatePSt2tm /var/tmp/no-tm-e5c67b.o ld: fatal: symbol referencing errors clang-5.0: error: linker command failed with exit code 1 (use -v to see invocation) ]
Basically any signature that includes either of the aforementioned types is mangled differently than whats in libstdc++.
Namely, clang mangles std::tm as std::tm (surpise! :), while gcc does it as ::tm.
Say, first undefined symbol above:
] nm /usr/lib/libstdc++.so | grep _ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE11do_get_timeES3_S3_RSt8ios_baseRSt12_Ios_Iostate [6646] | 533632| 276|FUNC |WEAK #0 llvm/llvm-project#1182 |_ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE11do_get_timeES3_S3_RSt8ios_baseRSt12_Ios_IostateP2tm ]
Notice 2tm vs St2tm difference at the tail of the mangled name.
See gcc mail thread that introduces this hack: https://gcc.gnu.org/ml/gcc-patches/2011-08/msg00834.html
assigned to @Theodor
This issue hit our own project in: https://github.com/llvm/llvm-project/pull/99075
Extended Description
g++ on Solaris has special mangling twist that makes it generate non-standard mangling for std::tm, std::div_t, std::ldiv_t, std::lconv types.
W/o this twist clang fails to link with libstdc++ on testcases like this:
] cat no-tm.cc
include
struct D : std::time_get {};
int main() { D var; var.date_order(); } ] clang no-tm.cc Undefined first referenced symbol in file _ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE11do_get_timeES3_S3_RSt8ios_baseRSt12_Ios_IostatePSt2tm /var/tmp/no-tm-e5c67b.o _ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE11do_get_dateES3_S3_RSt8ios_baseRSt12_Ios_IostatePSt2tm /var/tmp/no-tm-e5c67b.o _ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE14do_get_weekdayES3_S3_RSt8ios_baseRSt12_Ios_IostatePSt2tm /var/tmp/no-tm-e5c67b.o _ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE11do_get_yearES3_S3_RSt8ios_baseRSt12_Ios_IostatePSt2tm /var/tmp/no-tm-e5c67b.o _ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE16do_get_monthnameES3_S3_RSt8ios_baseRSt12_Ios_IostatePSt2tm /var/tmp/no-tm-e5c67b.o ld: fatal: symbol referencing errors clang-5.0: error: linker command failed with exit code 1 (use -v to see invocation) ]
Basically any signature that includes either of the aforementioned types is mangled differently than whats in libstdc++.
Namely, clang mangles std::tm as std::tm (surpise! :), while gcc does it as ::tm.
Say, first undefined symbol above:
] nm /usr/lib/libstdc++.so | grep _ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE11do_get_timeES3_S3_RSt8ios_baseRSt12_Ios_Iostate [6646] | 533632| 276|FUNC |WEAK #0 llvm/llvm-project#1182 |_ZNKSt8time_getIcSt19istreambuf_iteratorIcSt11char_traitsIcEEE11do_get_timeES3_S3_RSt8ios_baseRSt12_Ios_IostateP2tm ]
Notice 2tm vs St2tm difference at the tail of the mangled name.