Add Swift function ABI to rustc

Maps to LLVM's Swift calling convention, which is listed as 16.

Author: nvzqz

src/librustc/ich/impls_syntax.rs

@@ -81,6 +81,7 @@ impl_stable_hash_for!(enum ::rustc_target::spec::abi::Abi {
     AmdGpuKernel,
     Rust,
     C,
+    Swift,
     System,
     RustIntrinsic,
     RustCall,

src/librustc/ty/layout.rs

@@ -2599,6 +2599,7 @@ where
             Vectorcall => Conv::X86VectorCall,
             Thiscall => Conv::X86ThisCall,
             C => Conv::C,
+            Swift => Conv::Swift,
             Unadjusted => Conv::C,
             Win64 => Conv::X86_64Win64,
             SysV64 => Conv::X86_64SysV,

src/librustc_codegen_llvm/abi.rs

@@ -374,6 +374,7 @@ impl<'tcx> FnTypeLlvmExt<'tcx> for FnType<'tcx, Ty<'tcx>> {
     fn llvm_cconv(&self) -> llvm::CallConv {
         match self.conv {
             Conv::C => llvm::CCallConv,
+            Conv::Swift => llvm::SwiftCallConv,
             Conv::AmdGpuKernel => llvm::AmdGpuKernel,
             Conv::ArmAapcs => llvm::ArmAapcsCallConv,
             Conv::Msp430Intr => llvm::Msp430Intr,

src/librustc_codegen_llvm/llvm/ffi.rs

@@ -36,6 +36,7 @@ pub enum CallConv {
     CCallConv = 0,
     FastCallConv = 8,
     ColdCallConv = 9,
+    SwiftCallConv = 16,
     X86StdcallCallConv = 64,
     X86FastcallCallConv = 65,
     ArmAapcsCallConv = 67,

src/librustc_target/abi/call/mod.rs

@@ -491,6 +491,7 @@ impl<'a, Ty> ArgType<'a, Ty> {
 #[derive(Copy, Clone, PartialEq, Debug)]
 pub enum Conv {
     C,
+    Swift,
 
     ArmAapcs,
 

src/librustc_target/spec/abi.rs

@@ -25,6 +25,7 @@ pub enum Abi {
     // Multiplatform / generic ABIs
     Rust,
     C,
+    Swift,
     System,
     RustIntrinsic,
     RustCall,
@@ -62,6 +63,7 @@ const AbiDatas: &[AbiData] = &[
     // Cross-platform ABIs
     AbiData {abi: Abi::Rust, name: "Rust", generic: true },
     AbiData {abi: Abi::C, name: "C", generic: true },
+    AbiData {abi: Abi::Swift, name: "Swift", generic: true },
     AbiData {abi: Abi::System, name: "system", generic: true },
     AbiData {abi: Abi::RustIntrinsic, name: "rust-intrinsic", generic: true },
     AbiData {abi: Abi::RustCall, name: "rust-call", generic: true },

src/libsyntax/feature_gate/active.rs

@@ -519,6 +519,9 @@ declare_features! (
     /// Allows the use of or-patterns (e.g., `0 | 1`).
     (active, or_patterns, "1.38.0", Some(54883), None),
 
+    /// Allows using the `Swift` ABI.
+    (active, abi_swift, "1.38.0", Some(0), None),
+
     // -------------------------------------------------------------------------
     // feature-group-end: actual feature gates
     // -------------------------------------------------------------------------

src/libsyntax/feature_gate/check.rs

@@ -234,6 +234,10 @@ impl<'a> PostExpansionVisitor<'a> {
                 gate_feature_post!(&self, abi_amdgpu_kernel, span,
                                    "amdgpu-kernel ABI is experimental and subject to change");
             },
+            Abi::Swift => {
+                gate_feature_post!(&self, abi_swift, span,
+                                   "Swift ABI is experimental and subject to change");
+            },
             // Stable
             Abi::Cdecl |
             Abi::Stdcall |

src/libsyntax_pos/symbol.rs

@@ -109,6 +109,7 @@ symbols! {
     Symbols {
         aarch64_target_feature,
         abi,
+        abi_swift,
         abi_amdgpu_kernel,
         abi_msp430_interrupt,
         abi_ptx,