Add support for the "efiapi" ABI. (#2481)

This allows for use of `extern "efiapi" ...`
which is now stable since the following commit:
`https://github.com/rust-lang/rust/commit/46f9e878f68e6ece9e8dad54c67e97e5dd5838e1`

bindgen-cli/options.rs

@@ -336,7 +336,7 @@ struct BindgenCommand {
     /// Deduplicates extern blocks.
     #[arg(long)]
     merge_extern_blocks: bool,
-    /// Overrides the ABI of functions matching <regex>. The <OVERRIDE> value must be of the shape <REGEX>=<ABI> where <ABI> can be one of C, stdcall, fastcall, thiscall, aapcs, win64 or C-unwind.
+    /// Overrides the ABI of functions matching <regex>. The <OVERRIDE> value must be of the shape <REGEX>=<ABI> where <ABI> can be one of C, stdcall, efiapi, fastcall, thiscall, aapcs, win64 or C-unwind.
     #[arg(long, value_name = "OVERRIDE")]
     override_abi: Vec<String>,
     /// Wrap unsafe operations in unsafe blocks.

bindgen-tests/tests/headers/abi-override.h

@@ -1,5 +1,8 @@
-// bindgen-flags: --override-abi=foo=fastcall --override-abi=bar=stdcall
+// bindgen-flags: --override-abi=foo=fastcall --override-abi=bar=stdcall --override-abi=boo=efiapi --override-abi=foobar=efiapi
 
 void foo();
 void bar();
 void baz();
+
+typedef void (*boo)();
+typedef void (*foobar)(boo boo);

bindgen/codegen/mod.rs

@@ -2566,6 +2566,9 @@ impl Method {
             ClangAbi::Known(Abi::CUnwind) => {
                 ctx.options().rust_features().c_unwind_abi
             }
+            ClangAbi::Known(Abi::EfiApi) => {
+                ctx.options().rust_features().abi_efiapi
+            }
             _ => true,
         };
 
@@ -4089,9 +4092,8 @@ impl TryToRustTy for FunctionSig {
         // TODO: we might want to consider ignoring the reference return value.
         let ret = utils::fnsig_return_ty(ctx, self);
         let arguments = utils::fnsig_arguments(ctx, self);
-        let abi = self.abi(ctx, None);
 
-        match abi {
+        match self.abi(ctx, None) {
             ClangAbi::Known(Abi::ThisCall)
                 if !ctx.options().rust_features().thiscall_abi =>
             {
@@ -4110,7 +4112,13 @@ impl TryToRustTy for FunctionSig {
                 warn!("Skipping function with C-unwind ABI that isn't supported by the configured Rust target");
                 Ok(proc_macro2::TokenStream::new())
             }
-            _ => Ok(quote! {
+            ClangAbi::Known(Abi::EfiApi)
+                if !ctx.options().rust_features().abi_efiapi =>
+            {
+                warn!("Skipping function with efiapi ABI that isn't supported by the configured Rust target");
+                Ok(proc_macro2::TokenStream::new())
+            }
+            abi => Ok(quote! {
                 unsafe extern #abi fn ( #( #arguments ),* ) #ret
             }),
         }
@@ -4243,6 +4251,17 @@ impl CodeGenerator for Function {
                 );
                 return None;
             }
+            ClangAbi::Known(Abi::EfiApi)
+                if !ctx.options().rust_features().abi_efiapi =>
+            {
+                unsupported_abi_diagnostic::<true>(
+                    name,
+                    item.location(),
+                    "efiapi",
+                    ctx,
+                );
+                return None;
+            }
             ClangAbi::Known(Abi::Win64) if signature.is_variadic() => {
                 unsupported_abi_diagnostic::<true>(
                     name,

bindgen/features.rs

@@ -131,6 +131,9 @@ macro_rules! rust_target_base {
             /// Rust stable 1.64
             ///  * `core_ffi_c` ([Tracking issue](https://github.com/rust-lang/rust/issues/94501))
             => Stable_1_64 => 1.64;
+            /// Rust stable 1.68
+            ///  * `abi_efiapi` calling convention ([Tracking issue](https://github.com/rust-lang/rust/issues/65815))
+            => Stable_1_68 => 1.68;
             /// Nightly rust
             ///  * `thiscall` calling convention ([Tracking issue](https://github.com/rust-lang/rust/issues/42202))
             ///  * `vectorcall` calling convention (no tracking issue)
@@ -144,7 +147,7 @@ rust_target_base!(rust_target_def);
 rust_target_base!(rust_target_values_def);
 
 /// Latest stable release of Rust
-pub const LATEST_STABLE_RUST: RustTarget = RustTarget::Stable_1_64;
+pub const LATEST_STABLE_RUST: RustTarget = RustTarget::Stable_1_68;
 
 /// Create RustFeatures struct definition, new(), and a getter for each field
 macro_rules! rust_feature_def {
@@ -241,6 +244,9 @@ rust_feature_def!(
     Stable_1_64 {
         => core_ffi_c;
     }
+    Stable_1_68 {
+        => abi_efiapi;
+    }
     Nightly {
         => thiscall_abi;
         => vectorcall_abi;

bindgen/ir/function.rs

@@ -176,6 +176,8 @@ pub enum Abi {
     C,
     /// The "stdcall" ABI.
     Stdcall,
+    /// The "efiapi" ABI.
+    EfiApi,
     /// The "fastcall" ABI.
     Fastcall,
     /// The "thiscall" ABI.
@@ -197,6 +199,7 @@ impl FromStr for Abi {
         match s {
             "C" => Ok(Self::C),
             "stdcall" => Ok(Self::Stdcall),
+            "efiapi" => Ok(Self::EfiApi),
             "fastcall" => Ok(Self::Fastcall),
             "thiscall" => Ok(Self::ThisCall),
             "vectorcall" => Ok(Self::Vectorcall),
@@ -213,6 +216,7 @@ impl std::fmt::Display for Abi {
         let s = match *self {
             Self::C => "C",
             Self::Stdcall => "stdcall",
+            Self::EfiApi => "efiapi",
             Self::Fastcall => "fastcall",
             Self::ThisCall => "thiscall",
             Self::Vectorcall => "vectorcall",
@@ -263,6 +267,9 @@ impl quote::ToTokens for ClangAbi {
 /// A function signature.
 #[derive(Debug)]
 pub(crate) struct FunctionSig {
+    /// The name of this function signature.
+    name: String,
+
     /// The return type of the function.
     return_type: TypeId,
 
@@ -572,7 +579,8 @@ impl FunctionSig {
             warn!("Unknown calling convention: {:?}", call_conv);
         }
 
-        Ok(FunctionSig {
+        Ok(Self {
+            name: spelling,
             return_type: ret,
             argument_types: args,
             is_variadic: ty.is_variadic(),
@@ -611,6 +619,13 @@ impl FunctionSig {
             } else {
                 self.abi
             }
+        } else if let Some((abi, _)) = ctx
+            .options()
+            .abi_overrides
+            .iter()
+            .find(|(_, regex_set)| regex_set.matches(&self.name))
+        {
+            ClangAbi::Known(*abi)
         } else {
             self.abi
         }