`is_pub` added to `Fn` would cost us an additional 8
bytes of memory per function, which is a real bummer
since it's only 1 bit of information.
If we wanted to really remove this, I suspect we could
make this a function isPub() which looks at the AST of
the corresponding Decl and finds if the FnProto AST node
has the pub token. However I saw an easier approach -
The data of whether something is pub or not is actually
a property of a Decl anyway, not a function, so we can
look at moving the field into Decl. Indeed, doing this,
we see that Decl already has deletion_flag: bool which
is hiding in the padding bytes between the enum (1 byte)
and the following u32 field (generation). So if we put
the is_pub bool there, it actually will take up no
additional space, with 1 byte of padding remaining.
This was an easy reworking of the code since any
func.is_pub could be changed simply to func.owner_decl.is_pub.
I also modified `Var` to make the init value non-optional
and moved the optional bit to a has_init: bool field. This is worse from
the perspective of control flow and safety, however it makes
`@sizeOf(Var)` go from 32 bytes to 24 bytes. The more code we can fit
into memory at once, the more justified we are in using the compiler as
a long-running process that does incremental updates.
* introduce a dump() function on Module.Fn which helpfully prints to
stderr the ZIR representation of a function (can be called before
attempting to codegen it). This is a debugging tool.
* implement x86 codegen for loops
* liveness: fix analysis of conditional branches. The logic was buggy
in a couple ways:
- it never actually saved the results into the IR instruction (fixed now)
- it incorrectly labeled operands as dying when their true death was
after the conditional branch ended (fixed now)
* zir rendering is enhanced to show liveness analysis results. this
helps when debugging liveness analysis.
* fix bug in zir rendering not numbering instructions correctly
closes#6021
* `optimize_mode` is passed to `link.File` and stored there
* improve the debugging function `Module.dumpInst`
* get rid of `Value.the_one_possible_value` in favor of a few more
specific values for different types. This is less buggy, one less
footgun.
* `Type.onePossibleValue` now returns a `?Value` instead of `bool`.
* codegen handles undefined values. `undef` is a new `MCValue` tag.
It uses 0xaa values depending on optimization mode. However
optimization mode does not yet support scope overrides.
* link.zig: move the `Options` field from `File.Elf` and `File.C` to
the base struct.
- fix the Tag enum to adhere to style conventions
* ZIR now supports emitting undefined values.
* Fix the logic of comptime math to properly compare against zero using
the `compareWithZero` function.
* implement sema for runtime deref, store pointer, coerce_to_ptr_elem,
and store
* identifiers support being lvalues, except for decls is still TODO
* codegen supports load, store, ref, alloc
* introduce more MCValue union tags to support pointers
* add load, ref, store typed IR instructions
* add Type.isVolatilePtr
Comment out non-x86_64 architectures for now in codegen.zig, because
they all have compile errors for their codepaths anyway, and it was
bloating the compilation speed and memory usage when stage1 tried to
build self-hosted. Here's the panic message:
"Backend architectures that don't have good support yet are commented
out, to improve compilation performance. If you are interested in one
of these other backends feel free to uncomment them. Eventually these
will be completed, but stage1 is slow and a memory hog."
This is a workaround to lower the time it takes to build self-hosted
with stage1 as well as use less memory. It should fix the CI.
Additionally:
* Add `single_mut_pointer` support to `Type`
* Trivial implementation of stack allocation in codegen.zig. It does
not deal with freeing yet, and it's missing the stack pointer
adjustment prologue.
* Add the `alloc` IR instruction and semantic analysis for `alloc` ZIR
instruction.
* AST: flatten ControlFlowExpression into Continue, Break, and Return.
* AST: unify identifiers and literals into the same AST type: OneToken
* AST: ControlFlowExpression uses TrailerFlags to optimize storage
space.
* astgen: support `var` as well as `const` locals, and support
explicitly typed locals. Corresponding Module and codegen code is not
implemented yet.
* astgen: support result locations.
* ZIR: add the following instructions (see the corresponding doc
comments for explanations of semantics):
- alloc
- alloc_inferred
- bitcast_result_ptr
- coerce_result_block_ptr
- coerce_result_ptr
- coerce_to_ptr_elem
- ensure_result_used
- ensure_result_non_error
- ret_ptr
- ret_type
- store
- param_type
* the skeleton structure for result locations is set up. It's looking
pretty clean so far.
* add compile error for unused result and compile error for discarding
errors.
* astgen: split builtin calls up to implemented manually, and implement
`@as`, `@bitCast` (and others) with respect to result locations.
* add CLI support for hex and raw object formats. They are not
supported by the self-hosted compiler yet, and emit errors.
* rename `--c` CLI to `-ofmt=[objectformat]` which can be any of the
object formats. Only ELF and C are supported so far. Also added missing
help to the help text.
* Remove hard tabs from C backend test cases. Shame on you Noam, you
are grounded, you should know better, etc. Bad boy.
* Delete C backend code and test case that relied on comptime_int
incorrectly making it all the way to codegen.
These are now supported enough that this example code hits the
limitations of the register allocator:
fn add(a: u32, b: u32) void {
const c = a + b; // 7
const d = a + c; // 10
const e = d + b; // 14
assert(e == 14);
}
// error: TODO implement copyToNewRegister
So now the next step is to implement register allocation as planned.
