Instead of doing everything at once which is a hopelessly large task,
this introduces a piecemeal transition that can be done in small
increments at a time.
This is a minimal changeset that keeps the compiler compiling. It only
uses the InternPool for a small set of types.
Behavior tests are not passing.
Air.Inst.Ref and Zir.Inst.Ref are separated into different enums but
compile-time verified to have the same fields in the same order.
The large set of changes is mainly to deal with the fact that most Type
and Value methods now require a Module to be passed in, so that the
InternPool object can be accessed.
Fixes https://github.com/ziglang/zig/issues/14465
For aarch64, LLVM was crashing because Zig commands it to generate FPU code
even when there is no FPU present. This commit implements the necessary checks
to avoid this undesired situation and aarch64 can be compiled again with
no FPU.
Previously we did not write any missing padding bytes after the smallest
field (either tag or payload, depending on alignment). This resulted in
writing too few bytes and not matching the full abisize of the union.
When storing the address after calculating the element's address,
ensure it's stored in a local with the correct type. Previously it
would incorrectly use the element's type, which could be a float for
example and therefore generate invalid WebAssembly code.
This change also introduces a more robust `store` function.
When the paylaod is zero-sized we must ensure a valid pointer
is still returned for the ptr variation of the instruction. This,
because it's valid to have a pointer to a zero-sized value.
In such a case, we simply return the operand.
For packed unions where its abi size is less than or equal to 8 bytes
we store it directly and don't pass it by reference. This means that
when retrieving the field, we will perform shifts and bitcasts to ensure
the correct type is returned. For larger packed unions, we either allocate
a new stack value based on the field type when the field type is also passed
by reference, or load it directly into a local if it's not.
We currently have `isRef` return true for any type of union, including
packed unions. This means we can simply load it from the data section
to the exact type we want. In the future we can optimize it so it works
similarly to packed structs below 64 bits which do not get stored in
the data section and are not passed by ref.
Previously we would only store the payload, but not the actual tag
that was set. This meant miscompilations where it would incorrectly
return the tag value.
This also adds a tiny optimization for payloads which are not `byRef`
by directly storing them based on offset, rather than first calculating
a pointer to an offset.
Previously it was incorrectly assumed that all memcopy's generated by
the `memcpy` AIR instruction had an element size of 1 byte. However,
this would result in miscompilations for pointer's to arrays where
the element size of the array was larger than 1 byte. We now corectly
calculate this size.
`-l :path/to/lib.so` behavior on gcc/clang is:
- the path is recorded as-is: no paths, exact filename (`libX.so.Y`).
- no rpaths.
The previous version removed the `:` and pretended it's a positional
argument to the linker. That works in almost all cases, except in how
rules_go[1] does things (the Bazel wrapper for Go).
Test case in #15743, output:
gcc rpath:
0x0000000000000001 (NEEDED) Shared library: [libversioned.so.2]
0x000000000000001d (RUNPATH) Library runpath: [$ORIGIN/x]
gcc plain:
0x0000000000000001 (NEEDED) Shared library: [libversioned.so.2]
zig cc rpath:
0x0000000000000001 (NEEDED) Shared library: [libversioned.so.2]
0x000000000000001d (RUNPATH) Library runpath: [$ORIGIN/x]
zig cc plain:
0x0000000000000001 (NEEDED) Shared library: [libversioned.so.2]
Fixes#15743
[1]: https://github.com/bazelbuild/rules_go
The idea here is that there are two ways we can reference a function at runtime:
* Through a direct call, i.e. where the function is comptime-known
* Through a function pointer
This means we can easily perform a form of rudimentary escape analysis
on functions. If we ever see a `decl_ref` or `ref` of a function, we
have a function pointer, which could "leak" into runtime code, so we
emit the function; but for a plain `decl_val`, there's no need to.
This change means that `comptime { _ = f; }` no longer forces a function
to be emitted, which was used for some things (mainly tests). These use
sites have been replaced with `_ = &f;`, which still triggers analysis
of the function body, since you're taking a pointer to the function.
Resolves: #6256Resolves: #15353
