[llvm] [SHT_LLVM_BB_ADDR_MAP] Deprecate SHT_LLVM_BB_ADDR_MAP versions 0 and 1. (PR #74107)

[Rahman Lavaee via llvm-commits]

rlavaee wrote:

> I'll admit to not knowing how this code is used in anger, but it seems wrong to me to drop reading support of the section such that llvm-readobj can't read it anymore, especially as 9 months isn't actually all that long a period of time in my experience (we have codebases containing prebuilt binaries that are many years old, for example). There's also a difference between deprecating and dropping support entirely too, in my mind (the former is more of an announcement that support will be removed in the future). Is the old code causing a real maintenance issue?

I see your concern. For instance debug info requires a much longer support since it's needed to run the binary under gdb.
However, BB_ADDR_MAP is currently only used for profiling, which is only needed during the build. We actually plan to have a 6 month deprecation period to reduce the tech-debt.

https://github.com/llvm/llvm-project/pull/74107