rust/compiler/rustc_target
Andy-Python-Programmer db1e49257e
Use small code model for UEFI targets
* Since the code model only applies to the code and not the data and the code model
only applies to functions you call through using `call`, `jmp` and data with `lea`, etc…

If you are calling functions using the function pointers from the UEFI structures the code
model does not apply in that case. It’s just related to the address space size of your own binary.
Since UEFI (uefi is all relocatable) uses relocatable PEs (relocatable code does not care about the
code model) so, we use the small code model here.

* Since applications don't usually take gigabytes of memory, setting the
target to use the small code model should result in better codegen (comparable
with majority of other targets).

Large code models are also known for generating horrible code, for
example 16 bytes of code to load a single 8-byte value.

* Use the LLVM default code model for the architecture for the
x86_64-unknown-uefi targets. For reference small is the default
code model on x86 in LLVM: <7de2173c2a/llvm/lib/Target/X86/X86TargetMachine.cpp (L204)>

* Remove the comments too as they are not UEFI-specific and applies
to pretty much any target. I added them before as I was explicitily
setting the code model to small.

Signed-off-by: Andy-Python-Programmer <andypythonappdeveloper@gmail.com>
2021-07-17 14:08:40 +10:00
..
src Use small code model for UEFI targets 2021-07-17 14:08:40 +10:00
Cargo.toml
README.md Fix outdated crate names in compiler docs 2021-04-08 11:12:14 -05:00

rustc_target contains some very low-level details that are specific to different compilation targets and so forth.

For more information about how rustc works, see the rustc dev guide.