macOS requires the debug symbols to either be part of the intermediate
object file `whatever.o` or a companion `whatever.dSym` bundle. The
former case seems ill-suited for our needs since it subscribes to
the old-fashioned compilation strategy using intermediate compilation
units; the latter is what we need however on macOS the debug symbols
unlike in Elf are not part of the final artefact; rather they sit
next to it in its own Mach-O file.
One exception will be treatment of the __LINKEDIT segment which
will be handled separately inside MachO directly since it doesn't
include any sections.
This patch introduces the following new things:
Types:
- inferred_alloc
- This is a special value that tracks a set of types that have been stored
to an inferred allocation. It does not support most of the normal type queries.
However it does respond to `isConstPtr`, `ptrSize`, `zigTypeTag`, etc.
- The payload for this type simply points to the corresponding Value
payload.
Values:
- inferred_alloc
- This is a special value that tracks a set of types that have been stored
to an inferred allocation. It does not support any of the normal value queries.
ZIR instructions:
- store_to_inferred_ptr,
- Same as `store` but the type of the value being stored will be used to infer
the pointer type.
- resolve_inferred_alloc
- Each `store_to_inferred_ptr` puts the type of the stored value into a set,
and then `resolve_inferred_alloc` triggers peer type resolution on the set.
The operand is a `alloc_inferred` or `alloc_inferred_mut` instruction, which
is the allocation that needs to have its type inferred.
Changes to the C backend:
* Implements the bitcast instruction. If the source and dest types
are both pointers, uses a cast, otherwise uses memcpy.
* Tests are run with -Wno-declaration-after-statement. Someday we can
conform to this but not today.
In ZIR form it looks like this:
```zir
fn_body main { // unanalyzed
%0 = dbg_stmt()
=>%1 = alloc_inferred()
%2 = declval_in_module(Decl(add))
%3 = deref(%2)
%4 = param_type(%3, 0)
%5 = const(TypedValue{ .ty = comptime_int, .val = 1})
%6 = as(%4, %5)
%7 = param_type(%3, 1)
%8 = const(TypedValue{ .ty = comptime_int, .val = 2})
%9 = as(%7, %8)
%10 = call(%3, [%6, %9], modifier=auto)
=>%11 = store_to_inferred_ptr(%1, %10)
=>%12 = resolve_inferred_alloc(%1)
%13 = dbg_stmt()
%14 = ret_type()
%15 = const(TypedValue{ .ty = comptime_int, .val = 3})
%16 = sub(%10, %15)
%17 = as(%14, %16)
%18 = return(%17)
} // fn_body main
```
I have not played around with very many test cases yet. Some interesting
ones that I want to look at before merging:
```zig
var x = blk: {
var y = foo();
y.a = 1;
break :blk y;
};
```
In the above test case, x and y are supposed to alias.
```zig
var x = if (bar()) blk: {
var y = foo();
y.a = 1;
break :blk y;
} else blk: {
var z = baz();
z.b = 1;
break :blk z;
};
```
In the above test case, x, y, and z are supposed to alias.
I also haven't tested with `var` instead of `const` yet.
This is the same as the previous commit but for Value instead of Type.
Add `Value.castTag` and note that it is preferable to call than
`Value.cast`. This matches other abstractions in the codebase.
Added a convenience function `Value.Tag.create` which really cleans up
the callsites of creating `Value` objects.
`Value` tags can now share payload types. This is in preparation for
another improvement that I want to do.
Add `Type.castTag` and note that it is preferable to call than
`Type.cast`. This matches other abstractions in the codebase.
Added a convenience function `Type.Tag.create` which really cleans up
the callsites of creating `Type` objects.
`Type` payloads can now share types. This is in preparation for another
improvement that I want to do.
The current API does not allow the user to distinguish between EOF and
an empty line. Reader.readUntilDelimiterOrEof() gets this API right so
update readUntilDelimiterOrEofAlloc() to match it. Returning an optional
here additionally makes calling this in a loop much cleaner.
Remove readUntilDelimiterOrEofArrayList() as it no longer needed to
implement readUntilDelimiterOrEof() and has the same API issues
described without a clear way to fix them.
