--- /dev/null
+// This defines a base target-configuration for native UEFI systems. The UEFI specification has
+// quite detailed sections on the ABI of all the supported target architectures. In almost all
+// cases it simply follows what Microsoft Windows does. Hence, whenever in doubt, see the MSDN
+// documentation.
+// UEFI uses COFF/PE32+ format for binaries. All binaries must be statically linked. No dynamic
+// linker is supported. As native to COFF, binaries are position-dependent, but will be relocated
+// by the loader if the pre-chosen memory location is already in use.
+// UEFI forbids running code on anything but the boot-CPU. No interrupts are allowed other than
+// the timer-interrupt. Device-drivers are required to use polling-based models. Furthermore, all
+// code runs in the same environment, no process separation is supported.
+
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, StackProbeType, TargetOptions};
+
+pub fn opts() -> TargetOptions {
+ let mut base = super::msvc_base::opts();
+
+ let pre_link_args_msvc = vec![
+ // Non-standard subsystems have no default entry-point in PE+ files. We have to define
+ // one. "efi_main" seems to be a common choice amongst other implementations and the
+ // spec.
+ "/entry:efi_main".to_string(),
+ // COFF images have a "Subsystem" field in their header, which defines what kind of
+ // program it is. UEFI has 3 fields reserved, which are EFI_APPLICATION,
+ // EFI_BOOT_SERVICE_DRIVER, and EFI_RUNTIME_DRIVER. We default to EFI_APPLICATION,
+ // which is very likely the most common option. Individual projects can override this
+ // with custom linker flags.
+ // The subsystem-type only has minor effects on the application. It defines the memory
+ // regions the application is loaded into (runtime-drivers need to be put into
+ // reserved areas), as well as whether a return from the entry-point is treated as
+ // exit (default for applications).
+ "/subsystem:efi_application".to_string(),
+ ];
+ base.pre_link_args.get_mut(&LinkerFlavor::Msvc).unwrap().extend(pre_link_args_msvc.clone());
+ base.pre_link_args
+ .get_mut(&LinkerFlavor::Lld(LldFlavor::Link))
+ .unwrap()
+ .extend(pre_link_args_msvc);
+
+ TargetOptions {
+ os: "uefi".to_string(),
+ linker_flavor: LinkerFlavor::Lld(LldFlavor::Link),
+ disable_redzone: true,
+ exe_suffix: ".efi".to_string(),
+ allows_weak_linkage: false,
+ panic_strategy: PanicStrategy::Abort,
+ // LLVM does not emit inline assembly because the LLVM target does not get considered as…
+ // "Windows".
+ stack_probes: StackProbeType::Call,
+ singlethread: true,
+ linker: Some("rust-lld".to_string()),
+ ..base
+ }
+}