Extern functions were missing attributes such as "readonly" on
non-optional pointers, and "byval" which is required to match C ABI.
Follow-up from bf28765a975355c27558eaa86cf00ccb29b663a7.
closes#12683
This is problematic because in practice it depends on whether the
compiler backend supports it too, as evidenced by the TODO comment about
LLVM not supporting some architectures that in fact do support tail
calls.
Instead this logic is organized strategically in src/target.zig, part of
the internal compiler source code, and the behavior tests in question
duplicate some logic for deciding whether to proceed with the test.
The proper place to expose this flag is in `@import("builtin")` - the
generated source file - so that third party compilers can advertise
whether they support tail calls.
This also fixes performing relocations for data symbols
of which the target symbol exists in an external object file.
We do this by checking if the target symbol was discarded,
and if so: get the new location so that we can find the
corresponding atom that belongs to said new location. Previously
it would always assume the symbol would live in the same file
as the atom/symbol that is doing the relocation.
Generate symbols for extern variables and try to resolve them.
Unresolved 'data' symbols generate an error as they cannot be
exported from the Wasm runtime into a Wasm module. This means,
they can only be resolved by other object files such as from other
Zig or C code compiled to Wasm.
Given that COFF will want to support PIC from ground-up, there is no
point in leaving outdated code for COFF in other backends such as
arm or aarch64. Instead, when we are ready to look into those, we
can start figuring out what to add and where.
This is not technically correct, but given that we are not yet able
to link against the CRT, it's a good default until then.
Add basic logging of generated symbol table in the linker.
Regardless of the build mode (build-exe, build-lib), always
set the default stack size to 1MB. Previously, this was only
done when using build-exe, making the inconsistancy confusing.
The user can still override this behavior by providing the
`--stack <size>` flag.
