34 lines
903 B
Markdown
34 lines
903 B
Markdown
|
# Code Generation
|
||
|
|
|
||
|
|
## Data Representation
|
||
|
|
|
||
|
|
Every type has a "handle". If a type is a simple primitive type such as i32 or
|
||
|
|
f64, the handle is "by value", meaning that we pass around the value itself when
|
||
|
|
we refer to a value of that type.
|
||
|
|
|
||
|
|
If a type is a container, error union, maybe type, slice, or array, then its
|
||
|
|
handle is a pointer, and everywhere we refer to a value of this type we refer to
|
||
|
|
a pointer.
|
||
|
|
|
||
|
|
Parameters and return values are always passed as handles.
|
||
|
|
|
||
|
|
Error union types are represented as:
|
||
|
|
|
||
|
|
struct {
|
||
|
|
error: u32,
|
||
|
|
payload: T,
|
||
|
|
}
|
||
|
|
|
||
|
|
Maybe types are represented as:
|
||
|
|
|
||
|
|
struct {
|
||
|
|
payload: T,
|
||
|
|
is_non_null: u1,
|
||
|
|
}
|
||
|
|
|
||
|
|
## Data Optimizations
|
||
|
|
|
||
|
|
Maybe pointer types are special: the 0x0 pointer value is used to represent a
|
||
|
|
null pointer. Thus, instead of the struct above, maybe pointer types are
|
||
|
|
represented as a `usize` in codegen and the handle is by value.
|