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>
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 memory operand might use one of the extended GPRs R8 through R15 and
hence require a REX prefix, but having a REX prefix makes the high-byte
register AH unencodeable as the src operand. This latent bug was exposed
by this branch, presumably because `select` now happens to be putting
something in an extended GPR instead of a legacy GPR.
In theory this could be fixed with minimal cost by introducing a way to
communicate to `select` that neither the destination memory nor the
other temporary can be in an extended GPR. However, I just went for the
simple solution which comes at a cost of one trivial instruction: copy
the remainder from AH to AL, and *then* copy AL to the destination.
`rep movsb` isn't usually a great idea here. This commit makes the logic
which tentatively existed in `genInlineMemcpy` apply in more cases, and
in particular applies it to the "new" backend logic. Put simply, all
copies of 128 bytes or fewer will now attempt this path first,
where---provided there is an SSE register and/or a general-purpose
register available---we will lower the operation using a sequence of 32,
16, 8, 4, 2, and 1 byte copy operations.
The feedback I got on this diff was "Push it to master and if it
miscomps I'll revert it" so don't blame me when it explodes
Before https://github.com/ziglang/zig/pull/18160, error tracing defaulted to true in ReleaseSafe, but that is no longer the case. These option descriptions were never updating accordingly.
--debug-rt previously would make rt libs match the root module. Now they
are always debug when --debug-rt is passed. This includes compiler-rt,
fuzzer lib, and others.
