Add more *-unwind ABI variants

The following *-unwind ABIs are now supported:
- "C-unwind"
- "cdecl-unwind"
- "stdcall-unwind"
- "fastcall-unwind"
- "vectorcall-unwind"
- "thiscall-unwind"
- "aapcs-unwind"
- "win64-unwind"
- "sysv64-unwind"
- "system-unwind"

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -196,6 +196,54 @@ impl<'a> PostExpansionVisitor<'a> {
                     "thiscall-unwind ABI is experimental and subject to change"
                 );
             }
+            "cdecl-unwind" => {
+                gate_feature_post!(
+                    &self,
+                    c_unwind,
+                    span,
+                    "cdecl-unwind ABI is experimental and subject to change"
+                );
+            }
+            "fastcall-unwind" => {
+                gate_feature_post!(
+                    &self,
+                    c_unwind,
+                    span,
+                    "fastcall-unwind ABI is experimental and subject to change"
+                );
+            }
+            "vectorcall-unwind" => {
+                gate_feature_post!(
+                    &self,
+                    c_unwind,
+                    span,
+                    "vectorcall-unwind ABI is experimental and subject to change"
+                );
+            }
+            "aapcs-unwind" => {
+                gate_feature_post!(
+                    &self,
+                    c_unwind,
+                    span,
+                    "aapcs-unwind ABI is experimental and subject to change"
+                );
+            }
+            "win64-unwind" => {
+                gate_feature_post!(
+                    &self,
+                    c_unwind,
+                    span,
+                    "win64-unwind ABI is experimental and subject to change"
+                );
+            }
+            "sysv64-unwind" => {
+                gate_feature_post!(
+                    &self,
+                    c_unwind,
+                    span,
+                    "sysv64-unwind ABI is experimental and subject to change"
+                );
+            }
             "wasm" => {
                 gate_feature_post!(
                     &self,

compiler/rustc_metadata/src/native_libs.rs

@@ -404,11 +404,13 @@ impl Collector<'_> {
     fn build_dll_import(&self, abi: Abi, item: &hir::ForeignItemRef) -> DllImport {
         let calling_convention = if self.tcx.sess.target.arch == "x86" {
             match abi {
-                Abi::C { .. } | Abi::Cdecl => DllCallingConvention::C,
+                Abi::C { .. } | Abi::Cdecl { .. } => DllCallingConvention::C,
                 Abi::Stdcall { .. } | Abi::System { .. } => {
                     DllCallingConvention::Stdcall(self.i686_arg_list_size(item))
                 }
-                Abi::Fastcall => DllCallingConvention::Fastcall(self.i686_arg_list_size(item)),
+                Abi::Fastcall { .. } => {
+                    DllCallingConvention::Fastcall(self.i686_arg_list_size(item))
+                }
                 // Vectorcall is intentionally not supported at this time.
                 _ => {
                     self.tcx.sess.span_fatal(
@@ -419,7 +421,7 @@ impl Collector<'_> {
             }
         } else {
             match abi {
-                Abi::C { .. } | Abi::Win64 | Abi::System { .. } => DllCallingConvention::C,
+                Abi::C { .. } | Abi::Win64 { .. } | Abi::System { .. } => DllCallingConvention::C,
                 _ => {
                     self.tcx.sess.span_fatal(
                         item.span,

compiler/rustc_middle/src/ty/layout.rs

@@ -2773,17 +2773,20 @@ pub fn fn_can_unwind<'tcx>(
     // [rfc]: /~https://github.com/rust-lang/rfcs/blob/master/text/2945-c-unwind-abi.md
     use SpecAbi::*;
     match abi {
-        C { unwind } | Stdcall { unwind } | System { unwind } | Thiscall { unwind } => {
+        C { unwind }
+        | System { unwind }
+        | Cdecl { unwind }
+        | Stdcall { unwind }
+        | Fastcall { unwind }
+        | Vectorcall { unwind }
+        | Thiscall { unwind }
+        | Aapcs { unwind }
+        | Win64 { unwind }
+        | SysV64 { unwind } => {
             unwind
                 || (!tcx.features().c_unwind && tcx.sess.panic_strategy() == PanicStrategy::Unwind)
         }
-        Cdecl
-        | Fastcall
-        | Vectorcall
-        | Aapcs
-        | Win64
-        | SysV64
-        | PtxKernel
+        PtxKernel
         | Msp430Interrupt
         | X86Interrupt
         | AmdGpuKernel
@@ -2810,14 +2813,14 @@ pub fn conv_from_spec_abi(tcx: TyCtxt<'_>, abi: SpecAbi) -> Conv {
         EfiApi => bug!("eficall abi should be selected elsewhere"),
 
         Stdcall { .. } => Conv::X86Stdcall,
-        Fastcall => Conv::X86Fastcall,
-        Vectorcall => Conv::X86VectorCall,
+        Fastcall { .. } => Conv::X86Fastcall,
+        Vectorcall { .. } => Conv::X86VectorCall,
         Thiscall { .. } => Conv::X86ThisCall,
         C { .. } => Conv::C,
         Unadjusted => Conv::C,
-        Win64 => Conv::X86_64Win64,
-        SysV64 => Conv::X86_64SysV,
-        Aapcs => Conv::ArmAapcs,
+        Win64 { .. } => Conv::X86_64Win64,
+        SysV64 { .. } => Conv::X86_64SysV,
+        Aapcs { .. } => Conv::ArmAapcs,
         CCmseNonSecureCall => Conv::CCmseNonSecureCall,
         PtxKernel => Conv::PtxKernel,
         Msp430Interrupt => Conv::Msp430Intr,
@@ -2828,7 +2831,7 @@ pub fn conv_from_spec_abi(tcx: TyCtxt<'_>, abi: SpecAbi) -> Conv {
         Wasm => Conv::C,
 
         // These API constants ought to be more specific...
-        Cdecl => Conv::C,
+        Cdecl { .. } => Conv::C,
     }
 }
 

compiler/rustc_target/src/abi/call/mod.rs

@@ -658,22 +658,24 @@ impl<'a, Ty> FnAbi<'a, Ty> {
 
         match &cx.target_spec().arch[..] {
             "x86" => {
-                let flavor = if abi == spec::abi::Abi::Fastcall {
+                let flavor = if let spec::abi::Abi::Fastcall { .. } = abi {
                     x86::Flavor::Fastcall
                 } else {
                     x86::Flavor::General
                 };
                 x86::compute_abi_info(cx, self, flavor);
             }
-            "x86_64" => {
-                if abi == spec::abi::Abi::SysV64 {
-                    x86_64::compute_abi_info(cx, self);
-                } else if abi == spec::abi::Abi::Win64 || cx.target_spec().is_like_windows {
-                    x86_win64::compute_abi_info(self);
-                } else {
-                    x86_64::compute_abi_info(cx, self);
+            "x86_64" => match abi {
+                spec::abi::Abi::SysV64 { .. } => x86_64::compute_abi_info(cx, self),
+                spec::abi::Abi::Win64 { .. } => x86_win64::compute_abi_info(self),
+                _ => {
+                    if cx.target_spec().is_like_windows {
+                        x86_win64::compute_abi_info(self)
+                    } else {
+                        x86_64::compute_abi_info(cx, self)
+                    }
                 }
-            }
+            },
             "aarch64" => aarch64::compute_abi_info(cx, self),
             "amdgpu" => amdgpu::compute_abi_info(cx, self),
             "arm" => arm::compute_abi_info(cx, self),

compiler/rustc_target/src/spec/abi.rs

@@ -13,14 +13,14 @@ pub enum Abi {
     // churn. The specific values are meaningless.
     Rust,
     C { unwind: bool },
-    Cdecl,
+    Cdecl { unwind: bool },
     Stdcall { unwind: bool },
-    Fastcall,
-    Vectorcall,
+    Fastcall { unwind: bool },
+    Vectorcall { unwind: bool },
     Thiscall { unwind: bool },
-    Aapcs,
-    Win64,
-    SysV64,
+    Aapcs { unwind: bool },
+    Win64 { unwind: bool },
+    SysV64 { unwind: bool },
     PtxKernel,
     Msp430Interrupt,
     X86Interrupt,
@@ -50,16 +50,22 @@ const AbiDatas: &[AbiData] = &[
     AbiData { abi: Abi::Rust, name: "Rust" },
     AbiData { abi: Abi::C { unwind: false }, name: "C" },
     AbiData { abi: Abi::C { unwind: true }, name: "C-unwind" },
-    AbiData { abi: Abi::Cdecl, name: "cdecl" },
+    AbiData { abi: Abi::Cdecl { unwind: false }, name: "cdecl" },
+    AbiData { abi: Abi::Cdecl { unwind: true }, name: "cdecl-unwind" },
     AbiData { abi: Abi::Stdcall { unwind: false }, name: "stdcall" },
     AbiData { abi: Abi::Stdcall { unwind: true }, name: "stdcall-unwind" },
-    AbiData { abi: Abi::Fastcall, name: "fastcall" },
-    AbiData { abi: Abi::Vectorcall, name: "vectorcall" },
+    AbiData { abi: Abi::Fastcall { unwind: false }, name: "fastcall" },
+    AbiData { abi: Abi::Fastcall { unwind: true }, name: "fastcall-unwind" },
+    AbiData { abi: Abi::Vectorcall { unwind: false }, name: "vectorcall" },
+    AbiData { abi: Abi::Vectorcall { unwind: true }, name: "vectorcall-unwind" },
     AbiData { abi: Abi::Thiscall { unwind: false }, name: "thiscall" },
     AbiData { abi: Abi::Thiscall { unwind: true }, name: "thiscall-unwind" },
-    AbiData { abi: Abi::Aapcs, name: "aapcs" },
-    AbiData { abi: Abi::Win64, name: "win64" },
-    AbiData { abi: Abi::SysV64, name: "sysv64" },
+    AbiData { abi: Abi::Aapcs { unwind: false }, name: "aapcs" },
+    AbiData { abi: Abi::Aapcs { unwind: true }, name: "aapcs-unwind" },
+    AbiData { abi: Abi::Win64 { unwind: false }, name: "win64" },
+    AbiData { abi: Abi::Win64 { unwind: true }, name: "win64-unwind" },
+    AbiData { abi: Abi::SysV64 { unwind: false }, name: "sysv64" },
+    AbiData { abi: Abi::SysV64 { unwind: true }, name: "sysv64-unwind" },
     AbiData { abi: Abi::PtxKernel, name: "ptx-kernel" },
     AbiData { abi: Abi::Msp430Interrupt, name: "msp430-interrupt" },
     AbiData { abi: Abi::X86Interrupt, name: "x86-interrupt" },
@@ -101,32 +107,38 @@ impl Abi {
             C { unwind: false } => 1,
             C { unwind: true } => 2,
             // Platform-specific ABIs
-            Cdecl => 3,
-            Stdcall { unwind: false } => 4,
-            Stdcall { unwind: true } => 5,
-            Fastcall => 6,
-            Vectorcall => 7,
-            Thiscall { unwind: false } => 8,
-            Thiscall { unwind: true } => 9,
-            Aapcs => 10,
-            Win64 => 11,
-            SysV64 => 12,
-            PtxKernel => 13,
-            Msp430Interrupt => 14,
-            X86Interrupt => 15,
-            AmdGpuKernel => 16,
-            EfiApi => 17,
-            AvrInterrupt => 18,
-            AvrNonBlockingInterrupt => 19,
-            CCmseNonSecureCall => 20,
-            Wasm => 21,
+            Cdecl { unwind: false } => 3,
+            Cdecl { unwind: true } => 4,
+            Stdcall { unwind: false } => 5,
+            Stdcall { unwind: true } => 6,
+            Fastcall { unwind: false } => 7,
+            Fastcall { unwind: true } => 8,
+            Vectorcall { unwind: false } => 9,
+            Vectorcall { unwind: true } => 10,
+            Thiscall { unwind: false } => 11,
+            Thiscall { unwind: true } => 12,
+            Aapcs { unwind: false } => 13,
+            Aapcs { unwind: true } => 14,
+            Win64 { unwind: false } => 15,
+            Win64 { unwind: true } => 16,
+            SysV64 { unwind: false } => 17,
+            SysV64 { unwind: true } => 18,
+            PtxKernel => 19,
+            Msp430Interrupt => 20,
+            X86Interrupt => 21,
+            AmdGpuKernel => 22,
+            EfiApi => 23,
+            AvrInterrupt => 24,
+            AvrNonBlockingInterrupt => 25,
+            CCmseNonSecureCall => 26,
+            Wasm => 27,
             // Cross-platform ABIs
-            System { unwind: false } => 22,
-            System { unwind: true } => 23,
-            RustIntrinsic => 24,
-            RustCall => 25,
-            PlatformIntrinsic => 26,
-            Unadjusted => 27,
+            System { unwind: false } => 28,
+            System { unwind: true } => 29,
+            RustIntrinsic => 30,
+            RustCall => 31,
+            PlatformIntrinsic => 32,
+            Unadjusted => 33,
         };
         debug_assert!(
             AbiDatas

compiler/rustc_target/src/spec/mod.rs

@@ -1556,15 +1556,15 @@ impl Target {
                 Abi::Stdcall { unwind }
             }
             Abi::System { unwind } => Abi::C { unwind },
-            Abi::EfiApi if self.arch == "x86_64" => Abi::Win64,
+            Abi::EfiApi if self.arch == "x86_64" => Abi::Win64 { unwind: false },
             Abi::EfiApi => Abi::C { unwind: false },
 
             // See commentary in `is_abi_supported`.
             Abi::Stdcall { .. } | Abi::Thiscall { .. } if self.arch == "x86" => abi,
             Abi::Stdcall { unwind } | Abi::Thiscall { unwind } => Abi::C { unwind },
-            Abi::Fastcall if self.arch == "x86" => abi,
-            Abi::Vectorcall if ["x86", "x86_64"].contains(&&self.arch[..]) => abi,
-            Abi::Fastcall | Abi::Vectorcall => Abi::C { unwind: false },
+            Abi::Fastcall { .. } if self.arch == "x86" => abi,
+            Abi::Vectorcall { .. } if ["x86", "x86_64"].contains(&&self.arch[..]) => abi,
+            Abi::Fastcall { unwind } | Abi::Vectorcall { unwind } => Abi::C { unwind },
 
             abi => abi,
         }
@@ -1581,12 +1581,12 @@ impl Target {
             | RustCall
             | PlatformIntrinsic
             | Unadjusted
-            | Cdecl
+            | Cdecl { .. }
             | EfiApi => true,
             X86Interrupt => ["x86", "x86_64"].contains(&&self.arch[..]),
-            Aapcs => "arm" == self.arch,
+            Aapcs { .. } => "arm" == self.arch,
             CCmseNonSecureCall => ["arm", "aarch64"].contains(&&self.arch[..]),
-            Win64 | SysV64 => self.arch == "x86_64",
+            Win64 { .. } | SysV64 { .. } => self.arch == "x86_64",
             PtxKernel => self.arch == "nvptx64",
             Msp430Interrupt => self.arch == "msp430",
             AmdGpuKernel => self.arch == "amdgcn",
@@ -1623,13 +1623,13 @@ impl Target {
             // > convention is used.
             //
             // -- https://docs.microsoft.com/en-us/cpp/cpp/argument-passing-and-naming-conventions
-            Stdcall { .. } | Fastcall | Vectorcall if self.is_like_windows => true,
+            Stdcall { .. } | Fastcall { .. } | Vectorcall { .. } if self.is_like_windows => true,
             // Outside of Windows we want to only support these calling conventions for the
             // architectures for which these calling conventions are actually well defined.
-            Stdcall { .. } | Fastcall if self.arch == "x86" => true,
-            Vectorcall if ["x86", "x86_64"].contains(&&self.arch[..]) => true,
+            Stdcall { .. } | Fastcall { .. } if self.arch == "x86" => true,
+            Vectorcall { .. } if ["x86", "x86_64"].contains(&&self.arch[..]) => true,
             // Return a `None` for other cases so that we know to emit a future compat lint.
-            Stdcall { .. } | Fastcall | Vectorcall => return None,
+            Stdcall { .. } | Fastcall { .. } | Vectorcall { .. } => return None,
         })
     }
 

compiler/rustc_typeck/src/lib.rs

@@ -121,7 +121,7 @@ use bounds::Bounds;
 fn require_c_abi_if_c_variadic(tcx: TyCtxt<'_>, decl: &hir::FnDecl<'_>, abi: Abi, span: Span) {
     match (decl.c_variadic, abi) {
         // The function has the correct calling convention, or isn't a "C-variadic" function.
-        (false, _) | (true, Abi::C { .. }) | (true, Abi::Cdecl) => {}
+        (false, _) | (true, Abi::C { .. }) | (true, Abi::Cdecl { .. }) => {}
         // The function is a "C-variadic" function with an incorrect calling convention.
         (true, _) => {
             let mut err = struct_span_err!(

src/doc/unstable-book/src/language-features/c-unwind.md

@@ -6,9 +6,20 @@ The tracking issue for this feature is: [#74990]
 
 ------------------------
 
-Introduces four new ABI strings: "C-unwind", "stdcall-unwind",
-"thiscall-unwind", and "system-unwind". These enable unwinding from other
-languages (such as C++) into Rust frames and from Rust into other languages.
+Introduces new ABI strings:
+- "C-unwind"
+- "cdecl-unwind"
+- "stdcall-unwind"
+- "fastcall-unwind"
+- "vectorcall-unwind"
+- "thiscall-unwind"
+- "aapcs-unwind"
+- "win64-unwind"
+- "sysv64-unwind"
+- "system-unwind"
+
+These enable unwinding from other languages (such as C++) into Rust frames and
+from Rust into other languages.
 
 See [RFC 2945] for more information.