When LLVM_LINK_LLVM_DYLIB is ON, `check-bolt` target reports unit test
failures:
BOLT-Unit :: Core/./CoreTests/failed_to_discover_tests_from_gtest
BOLT-Unit :: Profile/./ProfileTests/failed_to_discover_tests_from_gtest
The reason is that when llvm-lit runs a unit-test executable:
/path/to/CoreTests --gtest_list_tests '--gtest_filter=-*DISABLED_*'
an assertion is triggered with the following message:
LLVM ERROR: Option 'default' already exists!
This assertion triggers when the initializer of defaultListDAGScheduler
defined at SelectionDAGISel.cpp:219 is called as a statically-linked
function after already being called during the initialization of
libLLVM.
The issue can be traced down to LLVMTestingSupport library which depends
on libLLVM as neither COMPONENT_LIB nor DISABLE_LLVM_LINK_LLVM_DYLIB is
specified in a call to `add_llvm_library(LLVMTestingSupport ...)`.
Specifying DISABLE_LLVM_LINK_LLVM_DYLIB for LLVMTestingSupport makes
Clang unit test fail and COMPONENT_LIB is probably inappropriate for a
testing-specific library, thus as a workaround, added Error.cpp source
from LLVMTestingSupport directly to the list of source files of
CoreTests target (as it depends on
`llvm::detail::TakeError(llvm::Error)`) and removed LLVMTestingSupport
from the list of dependencies of ProfileTests.
4da745a0f4