https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86490
--- Comment #13 from H.J. Lu <hjl.tools at gmail dot com> --- (In reply to zenith432 from comment #12) > Fair enough, it's a gold bug in the sense that gold's algorithm for > selecting a prevailing def among multiple defs has an error. > If an IR symbol has multiple definitions as > LDPK_COMMON > and a single definition as > LDPK_DEF > then the one marked as LDPK_DEF should be resolved as > LDPR_PREVAILING_DEF_IRNONLY and the other defintions as PREEMPTED_IR. > > However, the limitation of a single prevailing def is documented... > http://gcc.gnu.org/wiki/whopr/driver > In the subsection > The "All Symbols Read" Event > "In the case of a symbol that is defined in more than one IR file, WPA will > need to know which definition to use and which definitions to ignore." > > Logically, it is the linker's job to make this decision, because the > prevailing def depends on the order that object files are given on the > command line, on whether the object file has to be included in the link > (i.e. it's on the command line) - or it's in a library and is optional. And > also on whether it's a common def or not. lto1 cannot make this decision by > itself. > > It is not possible to leave multiple prevailing defs for lto1 just because > the linker doesn't need the symbol and considers it discardable - because an > IR symbol may be referenced from inside the IR by another part needed in the > link. In that case lto1 will need to generate the multiply defined symbol, > and can't decide which one to use - for example because it doesn't know the > order of the object files in the libraries given on the linker command line. But the symbol in question won't be USED by lto1 at all.
