This commit makes it possible to obtain pointers to `extern` variables
at comptime.
- `ir_get_var_ptr` employs several checks to determine if the given
variable is eligible for obtaining its pointer at comptime. This
commit alters these checks to consider `extern` variables, which have
runtime values, as eligible.
- After this change, it's now possible for `render_const_val` to be
called for `extern` variables. This commit modifies
`render_const_val` to suppress the value generation for `extern`
variables.
- `do_code_gen` now creates `ZigValue::llvm_global` of `extern`
variables before iterating through module-level variables so that
other module-level variables can refer to them.
This solution is incomplete since there are several cases still
failing:
- `global_var.array[n..m]`
- `&global_var.array[i]`
- `&global_var.inner_struct.value`
- `&global_array[i]`
Closes#5349
* 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 AST nodes now have a flags field and then a bunch of optional
trailing objects. The end result is lower memory usage and consequently
better performance. This is part of an ongoing effort to reduce the
amount of memory parsed ASTs take up.
Running `zig fmt` on the std lib:
* cache-misses: 2,554,321 => 2,534,745
* instructions: 3,293,220,119 => 3,302,479,874
* peak memory: 74.0 MiB => 73.0 MiB
Holding the entire std lib AST in memory at the same time:
93.9 MiB => 88.5 MiB
The indexes are stored separately using an array of
uint8_t, uint16_t, uint32_t, or size_t, depending on the number of
entries in the map.
Entries only contain a key and a value, no longer have
distance_from_start_index or is_used.
In theory this should be both faster and use less memory.
In practice it seems to have little to no effect. For the standard
library tests, vs master branch, the time had no discernable
difference, and it shaved off only 13 MiB of peak rss usage.
