Change Details

This reverts d53cb6ffcf6fddc63c399fb2ea4620e682597b38. It emulated pre glibc-2.2 behavior which was non-conforming. The non-compliant behavior provoked https://reviews.llvm.org/D4418 which was intended to fix -shared-libasan but introduced new problems (and caused some sanitizer tests (e.g. `test/asan/TestCases/interception_failure_test.cpp`) to fail): sanitizer interceptors are STB_GLOBAL instead of STB_WEAK, so defining a second STB_GLOBAL interceptor can lead to a multiple definition linker error. For example, in a `-fsanitize={address,memory,...}` build, libc functions like malloc/free/strtol/... cannot be provided by user object files. See https://docs.freebsd.org/cgi/getmsg.cgi?fetch=16483939+0+archive/2014/freebsd-current/20140716.freebsd-current for discussions.

The current lookup prefers a strong definition to a STB_WEAK definition (similar to glibc pre-2.2 behavior) which is non-conforming. The non-compliant behavior provoked https://reviews.llvm.org/D4418 which was intended to fix -shared-libasan but introduced new problems (and caused some sanitizer tests (e.g. `test/asan/TestCases/interception_failure_test.cpp`) to fail): sanitizer interceptors are STB_GLOBAL instead of STB_WEAK, so defining a second STB_GLOBAL interceptor can lead to a multiple definition linker error. For example, in a `-fsanitize={address,memory,...}` build, libc functions like malloc/free/strtol/... cannot be provided by user object files. See https://docs.freebsd.org/cgi/getmsg.cgi?fetch=16483939+0+archive/2014/freebsd-current/20140716.freebsd-current for discussions.

This reverts d53cb6ffcf6fddc63c399fb2ea4620e682597b38. It emulated pre The current lookup prefers a strong definition to a STB_WEAK definition (similar to glibc pre-2.2 behavior) which wais non-conforming. The non-compliant behavior provoked https://reviews.llvm.org/D4418 which was intended to fix -shared-libasan but introduced new problems (and caused some sanitizer tests (e.g. `test/asan/TestCases/interception_failure_test.cpp`) to fail): sanitizer interceptors are STB_GLOBAL instead of STB_WEAK, so defining a second STB_GLOBAL interceptor can lead to a multiple definition linker error. For example, in a `-fsanitize={address,memory,...}` build, libc functions like malloc/free/strtol/... cannot be provided by user object files. See https://docs.freebsd.org/cgi/getmsg.cgi?fetch=16483939+0+archive/2014/freebsd-current/20140716.freebsd-current for discussions.