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
One of the main motivating use cases for this language feature is
tracing/profiling tools, which expect null-terminated strings for these
values. Since the data is statically allocated, making them
additionally null-terminated comes at no cost.
This prevents the requirement of compile-time code to convert to
null-termination, which could increase the compilation time of
code with tracing enabled.
See #2029
Branch handling `*[N]T` to `E![]T` is already handled in a more complete
branch handling `*[N]T` to `[]T` *and* `*[N]T` to `E![]T` so it seems
safe to remove this one.
This will allow the developer to request additional memory pages
from the runtime to be allocated for the Wasm app. Typical usage:
```zig
var wasm_pages = @wasmMemorySize();
@wasmMemoryGrow(1);
@import("std").debug.assert((wasm_pages + 1) == @wasmMemorySize());
```
This will allow the developer to poll the runtime for currently
allocated memory in the number of Wasm pages. Typical usage:
```zig
var wasm_pages = @wasmMemorySize();
@import("std").debug.assert(wasm_pages > 0);
```
- for one-possible-value types, ir_analyze_struct_field_ptr()
no longer hardcodes const/volatile
- when slicing arrays, ir_analyze_instruction_slice()
no longer consults ConstValSpecialStatic
closes#5474
extracted function ir_try_evaluate_bin_op_const
extracted type_is_self_comparable function
renamed ir_try_evaluate_bin_op_const to ir_try_evaluate_bin_op_cmp_const
implemented analysis of ?T == T
added ir_set_cursor_at_end_and_append_basic_block_gen
use build_br_gen and ir_set_cursor_at_end_and_append_block_gen
added ir_append_basic_block_gen
removed include of all_types in ir.cpp
extracted compile-time and runtime evaluation of cmp_optional_non_optional to separate functions
closes#5390closes#1332
