REQUIRES: linux, lld-available

No gc-sections:
RUN: %cpp_compiler %S/GcSectionsTest.cpp -o %t
RUN: nm %t | grep UnusedFunctionShouldBeRemovedByLinker | count 1

With gc-sections. Currently, we can't remove unused code except with LLD.
RUN: %cpp_compiler %S/GcSectionsTest.cpp -o %t -fuse-ld=lld -ffunction-sections -Wl,-gc-sections
RUN: nm %t | not grep UnusedFunctionShouldBeRemovedByLinker
RUN: %run %t -runs=0 2>&1 | FileCheck %s
CHECK-NOT: ERROR: The size of coverage PC tables does not match

With gc sections, with trace-pc. Unused code is removed.
RUN: %cpp_compiler %S/GcSectionsTest.cpp -o %t -fsanitize-coverage=0 -fsanitize-coverage=trace-pc -ffunction-sections -Wl,-gc-sections
RUN: nm %t | not grep UnusedFunctionShouldBeRemovedByLinker