I’m attempting to build Firefox on Windows using clang-cl with -fprofile-instr-generate (*), but I’m running into some linker errors that I haven’t been able to make sense of.
lld-link.exe: error: duplicate symbol: _profc?width@ios_base@std@@QEBA_JXZ in minidump-analyzer.obj and in …\google-breakpad\src\processor\basic_code_modules.obj
lld-link.exe: error: duplicate symbol: _profc?flags@ios_base@std@@QEBAHXZ in minidump-analyzer.obj and in …\google-breakpad\src\processor\basic_code_modules.obj
lld-link.exe: error: duplicate symbol: _profc?rdbuf@?$basic_ios@DU?$char_traits@D@std@@@std@@QEBAPEAV?$basic_streambuf@DU?$char_traits@D@std@@@2@XZ in minidump-analyzer.obj and in …\google-breakpad\src\processor\basic_code_modules.obj
and several dozen more like this, all with a _profc prefix.
I had hoped to isolate this by linking some small test files that use iostreams, but they didn’t reproduce the error.
Does anybody have advice on how to debug this?
Thanks,
David
(*) It seems that -fprofile-instr-generate is my only option for PGO, as clang-cl.exe rejects both -fprofile-generate and -Xclang -fprofile-generate. (Is this intentional?)