forked from OSchip/llvm-project
232578804a
D77522 changed --warn-backrefs to not warn for linking sandwich problems (-ldef1 -lref -ldef2). This removed lots of false positives. However, glibc still has some problems. libc.a defines some symbols which are normally in libm.a and libpthread.a, e.g. __isnanl/raise. For a linking order `-lm -lpthread -lc`, I have seen: ``` // different resolutions: GNU ld/gold select libc.a(s_isnan.o) as the definition backward reference detected: __isnanl in libc.a(printf_fp.o) refers to libm.a(m_isnanl.o) // different resolutions: GNU ld/gold select libc.a(raise.o) as the definition backward reference detected: raise in libc.a(abort.o) refers to libpthread.a(pt-raise.o) ``` To facilitate deployment of --warn-backrefs, add --warn-backrefs-exclude= so that certain known issues (which may be impractical to fix) can be whitelisted. Deliberate choices: * Not a comma-separated list (`--warn-backrefs-exclude=liba.a,libb.a`). -Wl, splits the argument at commas, so we cannot use commas. --export-dynamic-symbol is similar. * Not in the style of `--warn-backrefs='*' --warn-backrefs=-liba.a`. We just need exclusion, not inclusion. For easier build system integration, we should avoid order dependency. With the current scheme, we enable --warn-backrefs, and indivial libraries can add --warn-backrefs-exclude=<glob> to their LDFLAGS. Reviewed By: psmith Differential Revision: https://reviews.llvm.org/D77512 |
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| COFF | ||
| Driver/Inputs | ||
| ELF | ||
| MachO | ||
| MinGW | ||
| Unit | ||
| darwin | ||
| mach-o | ||
| wasm | ||
| CMakeLists.txt | ||
| lit.cfg.py | ||
| lit.site.cfg.py.in | ||