| // This defines the amd64 target for UEFI systems as described in the UEFI specification. See the |
| // uefi-base module for generic UEFI options. On x86_64 systems (mostly called "x64" in the spec) |
| // UEFI systems always run in long-mode, have the interrupt-controller pre-configured and force a |
| // single-CPU execution. |
| // The win64 ABI is used. It differs from the sysv64 ABI, so we must use a windows target with |
| // LLVM. "x86_64-unknown-windows" is used to get the minimal subset of windows-specific features. |
| |
| use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetResult}; |
| |
| pub fn target() -> TargetResult { |
| let mut base = super::uefi_base::opts(); |
| base.cpu = "x86-64".to_string(); |
| base.max_atomic_width = Some(64); |
| |
| // We disable MMX and SSE for now, even though UEFI allows using them. Problem is, you have to |
| // enable these CPU features explicitly before their first use, otherwise their instructions |
| // will trigger an exception. Rust does not inject any code that enables AVX/MMX/SSE |
| // instruction sets, so this must be done by the firmware. However, existing firmware is known |
| // to leave these uninitialized, thus triggering exceptions if we make use of them. Which is |
| // why we avoid them and instead use soft-floats. This is also what GRUB and friends did so |
| // far. |
| // If you initialize FP units yourself, you can override these flags with custom linker |
| // arguments, thus giving you access to full MMX/SSE acceleration. |
| base.features = "-mmx,-sse,+soft-float".to_string(); |
| |
| // UEFI systems run without a host OS, hence we cannot assume any code locality. We must tell |
| // LLVM to expect code to reference any address in the address-space. The "large" code-model |
| // places no locality-restrictions, so it fits well here. |
| base.code_model = Some("large".to_string()); |
| |
| // UEFI mirrors the calling-conventions used on windows. In case of x86-64 this means small |
| // structs will be returned as int. This shouldn't matter much, since the restrictions placed |
| // by the UEFI specifications forbid any ABI to return structures. |
| base.abi_return_struct_as_int = true; |
| |
| Ok(Target { |
| llvm_target: "x86_64-unknown-windows".to_string(), |
| target_endian: "little".to_string(), |
| target_pointer_width: "64".to_string(), |
| target_c_int_width: "32".to_string(), |
| data_layout: "e-m:w-i64:64-f80:128-n8:16:32:64-S128".to_string(), |
| target_os: "uefi".to_string(), |
| target_env: "".to_string(), |
| target_vendor: "unknown".to_string(), |
| arch: "x86_64".to_string(), |
| linker_flavor: LinkerFlavor::Lld(LldFlavor::Link), |
| |
| options: base, |
| }) |
| } |