From 42cbb401574b494c5da7a58cb2485be54992babd Mon Sep 17 00:00:00 2001
From: Nicholas Bishop <nbishop@nbishop.net>
Date: Sun, 6 Nov 2022 17:29:46 -0500
Subject: [PATCH] Use aapcs for efiapi calling convention on arm

On arm, llvm treats the C calling convention as `aapcs` on soft-float
targets and `aapcs-vfp` on hard-float targets [1]. UEFI specifies in the
arm calling convention that floating point extensions aren't used [2],
so always translate `efiapi` to `aapcs` on arm.

[1]: https://github.com/rust-lang/compiler-builtins/issues/116#issuecomment-261057422
[2]: https://uefi.org/specs/UEFI/2.10/02_Overview.html#detailed-calling-convention

https://github.com/rust-lang/rust/issues/65815
---
 compiler/rustc_target/src/spec/mod.rs | 1 +
 src/test/codegen/abi-efiapi.rs        | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index 72b088d663b1f..b44ed8f3fa9a3 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -1915,6 +1915,7 @@ impl Target {
                 Abi::Stdcall { unwind }
             }
             Abi::System { unwind } => Abi::C { unwind },
+            Abi::EfiApi if self.arch == "arm" => Abi::Aapcs { unwind: false },
             Abi::EfiApi if self.arch == "x86_64" => Abi::Win64 { unwind: false },
             Abi::EfiApi => Abi::C { unwind: false },
 
diff --git a/src/test/codegen/abi-efiapi.rs b/src/test/codegen/abi-efiapi.rs
index b4fda5f8c8428..9061d7432a3fa 100644
--- a/src/test/codegen/abi-efiapi.rs
+++ b/src/test/codegen/abi-efiapi.rs
@@ -27,7 +27,7 @@ trait Copy { }
 //x86_64: define win64cc void @has_efiapi
 //i686: define void @has_efiapi
 //aarch64: define dso_local void @has_efiapi
-//arm: define dso_local void @has_efiapi
+//arm: define dso_local arm_aapcscc void @has_efiapi
 //riscv: define dso_local void @has_efiapi
 #[no_mangle]
 pub extern "efiapi" fn has_efiapi() {}