cmd/internal/obj: flag init functions in object file
Introduce a flag in the object file indicating whether a given
function corresponds to a compiler-generated (not user-written) init
function, such as "os.init" or "syscall.init". Add code to the
compiler to fill in the correct value for the flag, and add support to
the loader package in the linker for testing the flag. The new loader
API is currently unused, but will be needed in the next CL in this
stack.
Updates #2559.
Updates #36021.
Updates #14840.
Change-Id: Iea7ad2adda487e4af7a44f062f9817977c53b394
Reviewed-on: https://go-review.googlesource.com/c/go/+/463855 Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>