Auto merge of #1065 - liranringel:thiscall, r=fitzgen

Add support for the thiscall ABI

Fixes https://github.com/rust-lang-nursery/rust-bindgen/issues/541

The thiscall ABI is experimental, so in order to use it nightly is required and also the following statement:
`#![feature(abi_thiscall)]`
That's a problem because the `tests_expectations` crate (in the tests folder) tries to compile it (and stable is required).

3 files changed, 26 insertions, 3 deletions

diff --git a/src/codegen/mod.rs b/src/codegen/mod.rs
index 94a62b97..6d8e8a9d 100644
--- a/src/codegen/mod.rs
+++ b/src/codegen/mod.rs
@@ -1959,6 +1959,10 @@ impl MethodCodegen for Method {
             _ => panic!("How in the world?"),
         };
 
+        if let (Abi::ThisCall, false) = (signature.abi(), ctx.options().rust_features().thiscall_abi()) {
+            return;
+        }
+
         // Do not generate variadic methods, since rust does not allow
         // implementing them, and we don't do a good job at it anyway.
         if signature.is_variadic() {
@@ -3072,9 +3076,17 @@ impl TryToRustTy for FunctionSig {
         let arguments = utils::fnsig_arguments(ctx, &self);
         let abi = self.abi();
 
-        Ok(quote! {
-            unsafe extern #abi fn ( #( #arguments ),* ) #ret
-        })
+        match abi {
+            Abi::ThisCall if !ctx.options().rust_features().thiscall_abi() => {
+                warn!("Skipping function with thiscall ABI that isn't supported by the configured Rust target");
+                Ok(quote::Tokens::new())
+            }
+            _ => {
+                Ok(quote! {
+                    unsafe extern #abi fn ( #( #arguments ),* ) #ret
+                })
+            }
+        }
     }
 }
 
@@ -3146,6 +3158,10 @@ impl CodeGenerator for Function {
         }
 
         let abi = match signature.abi() {
+            Abi::ThisCall if !ctx.options().rust_features().thiscall_abi() => {
+                warn!("Skipping function with thiscall ABI that isn't supported by the configured Rust target");
+                return;
+            }
             Abi::Unknown(unknown_abi) => {
                 panic!(
                     "Invalid or unknown abi {:?} for function {:?} ({:?})",
diff --git a/src/features.rs b/src/features.rs
index 29e60ab7..b89185fd 100644
--- a/src/features.rs
+++ b/src/features.rs
@@ -140,6 +140,8 @@ rust_feature_def!(
     => untagged_union;
     /// Constant function ([RFC 911](https://github.com/rust-lang/rfcs/blob/master/text/0911-const-fn.md))
     => const_fn;
+    /// `thiscall` calling convention ([Tracking issue](https://github.com/rust-lang/rust/issues/42202))
+    => thiscall_abi;
 );
 
 impl From<RustTarget> for RustFeatures {
@@ -152,6 +154,7 @@ impl From<RustTarget> for RustFeatures {
 
         if rust_target >= RustTarget::Nightly {
             features.const_fn = true;
+            features.thiscall_abi = true;
         }
 
         features
diff --git a/src/ir/function.rs b/src/ir/function.rs
index b637f9f1..2eab6638 100644
--- a/src/ir/function.rs
+++ b/src/ir/function.rs
@@ -142,6 +142,8 @@ pub enum Abi {
     Stdcall,
     /// The "fastcall" ABI.
     Fastcall,
+    /// The "thiscall" ABI.
+    ThisCall,
     /// The "aapcs" ABI.
     Aapcs,
     /// The "win64" ABI.
@@ -166,6 +168,7 @@ impl quote::ToTokens for Abi {
             Abi::C => quote! { "C" },
             Abi::Stdcall => quote! { "stdcall" },
             Abi::Fastcall => quote! { "fastcall" },
+            Abi::ThisCall => quote! { "thiscall" },
             Abi::Aapcs => quote! { "aapcs" },
             Abi::Win64 => quote! { "win64" },
             Abi::Unknown(cc) => panic!(
@@ -200,6 +203,7 @@ fn get_abi(cc: CXCallingConv) -> Abi {
         CXCallingConv_C => Abi::C,
         CXCallingConv_X86StdCall => Abi::Stdcall,
         CXCallingConv_X86FastCall => Abi::Fastcall,
+        CXCallingConv_X86ThisCall => Abi::ThisCall,
         CXCallingConv_AAPCS => Abi::Aapcs,
         CXCallingConv_X86_64Win64 => Abi::Win64,
         other => Abi::Unknown(other),