[llvm] [RemoveDIs] Load into new debug info format by default in llvm-link (PR #86274)

[Jinsong Ji via llvm-commits]

jsji wrote:

Looks like this might cause assert failure for some scenarios.

Simple reproducer on x86 Linux:
```
# Build clang/llvm with -DLLVM_ENABLE_ASSERTIONS=ON

$cat t.cpp
int __attribute__((always_inline)) func(int x) {
   return x * 2;
 }
$ clang++ -g -c -emit-llvm t.cpp
$ llvm-link t.bc
```

```
Unknown function for CallBase upgrade.
UNREACHABLE executed at .../llvm-project/llvm/lib/IR/AutoUpgrade.cpp:4268!
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: bin/llvm-link t.bc
 #0 0x00007f06b58af4b1 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) .../llvm-project/build/bin/../lib/libLLVMSupport.so.19.0git+0x1cd4b1)
 #1 0x00007f06b58aca14 SignalHandler(int) Signals.cpp:0:0
 #2 0x00007f06b51f8db0 __restore_rt (/lib64/libc.so.6+0x59db0)
 #3 0x00007f06b524542c __pthread_kill_implementation (/lib64/libc.so.6+0xa642c)
 #4 0x00007f06b51f8d06 gsignal (/lib64/libc.so.6+0x59d06)
 #5 0x00007f06b51cb7d3 abort (/lib64/libc.so.6+0x2c7d3)
 #6 0x00007f06b57ceada (.../llvm-project/build/bin/../lib/libLLVMSupport.so.19.0git+0xecada)
 #7 0x00007f06b5ae5126 llvm::UpgradeIntrinsicCall(llvm::CallBase*, llvm::Function*) (.../llvm-project/build/bin/../lib/libLLVMCore.so.19.0git+0x13c126)
 #8 0x00007f06b5fb9e38 (anonymous namespace)::BitcodeReader::materialize(llvm::GlobalValue*) BitcodeReader.cpp:0:0
 #9 0x00007f06b5c91de7 llvm::Module::materialize(llvm::GlobalValue*) (.../llvm-project/build/bin/../lib/libLLVMCore.so.19.0git+0x2e8de7)
#10 0x00007f06b5bf6d81 llvm::GlobalValue::materialize() (.../llvm-project/build/bin/../lib/libLLVMCore.so.19.0git+0x24dd81)
#11 0x00007f06b65c0330 (anonymous namespace)::IRLinker::materialize(llvm::Value*, bool) IRMover.cpp:0:0
#12 0x00007f06b64b35ad (anonymous namespace)::Mapper::mapValue(llvm::Value const*) ValueMapper.cpp:0:0
#13 0x00007f06b64b8989 llvm::ValueMapper::mapValue(llvm::Value const&) (.../llvm-project/build/bin/../lib/libLLVMTransformUtils.so.19.0git+0x2c2989)
#14 0x00007f06b65c7416 llvm::IRMover::move(std::unique_ptr<llvm::Module, std::default_delete<llvm::Module>>, llvm::ArrayRef<llvm::GlobalValue*>, llvm::unique_function<void (llvm::GlobalValue&, std::function<void (llvm::GlobalValue&)>)>, bool) (.../llvm-project/build/bin/../lib/libLLVMLinker.so.19.0git+0x15416)
#15 0x00007f06b65d1392 (anonymous namespace)::ModuleLinker::run() LinkModules.cpp:0:0
#16 0x00007f06b65d177c llvm::Linker::linkInModule(std::unique_ptr<llvm::Module, std::default_delete<llvm::Module>>, unsigned int, std::function<void (llvm::Module&, llvm::StringSet<llvm::MallocAllocator> const&)>) (.../llvm-project/build/bin/../lib/libLLVMLinker.so.19.0git+0x1f77c)
#17 0x000000000040df9d linkFiles(char const*, llvm::LLVMContext&, llvm::Linker&, llvm::cl::list<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>, bool, llvm::cl::parser<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>>> const&, unsigned int) llvm-link.cpp:0:0
#18 0x000000000040659b main (bin/llvm-link+0x40659b)
#19 0x00007f06b51e3e50 __libc_start_call_main (/lib64/libc.so.6+0x44e50)
#20 0x00007f06b51e3efc __libc_start_main at GLIBC_2.2.5 (/lib64/libc.so.6+0x44efc)
#21 0x0000000000407ae5 _start (bin/llvm-link+0x407ae5)
Aborted (core dumped)
```



https://github.com/llvm/llvm-project/pull/86274