https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77342
Bug ID: 77342
Summary: Use abi_tag on Debug Mode namespace
Product: gcc
Version: 7.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: redi at gcc dot gnu.org
Target Milestone: ---
The libstdc++ Debug Mode changes the ABI of various types, requiring all
affected code to be recompiled. If some function is not recompiled, and the
debug mode type doesn't appear in its mangled name, then you get undefined
behaviour, typically resulting in runtime crashes, e.g. PR 77340.
If we used the abi_tag attribute on the inline namespace used for Debug Mode
components then it would turn run-time crashes into linker errors, or at least
warnings when a data member of a class changes size.
e.g. with:
// Inline namespace for debug mode.
# ifdef _GLIBCXX_DEBUG
inline namespace __debug __attribute__((__abi_tag__("__debug"))) { }
# endif
the code in PR 77340 fails to link:
/tmp/cccmvLXH.o: In function `main':
/tmp/main.cpp:4: undefined reference to `func()'
collect2: error: ld returned 1 exit status
