We mustn't emit the DT_PLTGOT entry in `.dynamic` in a statically-linked
PIE, because there's no dl to relocate it (and `std.pie.relocate`, or
the PIE relocator in libc, won't touch it). In that case, there cannot
be any PLT entries, so there's no point emitting the `.got.plt` section
at all. If we just don't create that section, `link.Elf` already knows
not to add the DT_PLTGOT entry to `.dynamic`.
Co-authored-by: Jacob Young <jacobly0@users.noreply.github.com>
This abstraction isn't really tied to DWARF at all! Really, we're just
loading some information from an ELF file which is useful for debugging.
That *includes* DWARF, but it also includes other information. For
instance, the other change here:
Now, if DWARF information is missing, `debug.SelfInfo.ElfModule` will
name symbols by finding a matching symtab entry. We actually already do
this on Mach-O, so it makes obvious sense to do the same on ELF! This
change is what motivated the restructuring to begin with.
The symtab work is derived from #22077.
Co-authored-by: geemili <opensource@geemili.xyz>
If it's not given, we should set `first_address` to the return address
of `dumpCurrentStackTrace` to avoid the call to `writeCurrentStackTrace`
appearing in the trace. However, we must only do that if no `context` is
given; if there's a context then we're starting the stack unwind
elsewhere.
At least, when there's not a ZigObject. The old behavior was incorrect
in the presence of a ZigObject, and this doesn't really mix nicely with
incremental compilation anyway; but when the objects are all external,
we may as well build the search table.
Far simpler, because everything which `crash_report.zig` did is now
handled pretty well by `std.debug` anyway. All we want is to print some
context around panics and segfaults. Using the new ability to override
the default segfault handler while still having std handle the
target-specific bits for us, that's really simple.
The downside of this commit is that more precise errors are no longer
propagated up. However, these errors were pretty useless in isolation
due to them having no context; and regardless, we intentionally swallow
most of them in `std.debug` anyway. Therefore, this is better in
practice, because it allows `std.debug` to give slightly more useful
warnings when handling errors. This commit does that for unwind errors,
for instance, which differentiate between the unwind info being corrupt
vs missing vs inaccessible vs unsupported.
A better solution would be to also include more detailed information via
the diagnostics pattern, but this commit is an incremental improvement.
turns out this isn't technically specific to that target at all; other
targets just don't emit mid-function 'ret' instructions as much so
certain CFI instruction patterns were only seen on aarch64.
thanks to jacob for finding the bug <3
