Teach rust core about Xtensa VaListImpl

Author: kelnos

library/core/src/ffi/mod.rs

@@ -227,7 +227,7 @@ impl fmt::Debug for c_void {
 /// Basic implementation of a `va_list`.
 // The name is WIP, using `VaListImpl` for now.
 #[cfg(any(
-    all(not(target_arch = "aarch64"), not(target_arch = "powerpc"), not(target_arch = "x86_64")),
+    all(not(target_arch = "aarch64"), not(target_arch = "powerpc"), not(target_arch = "x86_64"), not(target_arch = "xtensa")),
     all(target_arch = "aarch64", any(target_os = "macos", target_os = "ios")),
     target_family = "wasm",
     target_arch = "asmjs",
@@ -250,7 +250,7 @@ pub struct VaListImpl<'f> {
 }
 
 #[cfg(any(
-    all(not(target_arch = "aarch64"), not(target_arch = "powerpc"), not(target_arch = "x86_64")),
+    all(not(target_arch = "aarch64"), not(target_arch = "powerpc"), not(target_arch = "x86_64"), not(target_arch = "xtensa")),
     all(target_arch = "aarch64", any(target_os = "macos", target_os = "ios")),
     target_family = "wasm",
     target_arch = "asmjs",
@@ -335,6 +335,24 @@ pub struct VaListImpl<'f> {
     _marker: PhantomData<&'f mut &'f c_void>,
 }
 
+/// xtensa ABI implementation of a `va_list`.
+#[cfg(target_arch = "xtensa")]
+#[repr(C)]
+#[derive(Debug)]
+#[unstable(
+    feature = "c_variadic",
+    reason = "the `c_variadic` feature has not been properly tested on \
+              all supported platforms",
+    issue = "44930"
+)]
+#[lang = "va_list"]
+pub struct VaListImpl<'f> {
+    stk: *mut i32,
+    reg: *mut i32,
+    ndx: i32,
+    _marker: PhantomData<&'f mut &'f i32>,
+}
+
 /// A wrapper for a `va_list`
 #[repr(transparent)]
 #[derive(Debug)]
@@ -349,7 +367,8 @@ pub struct VaList<'a, 'f: 'a> {
         all(
             not(target_arch = "aarch64"),
             not(target_arch = "powerpc"),
-            not(target_arch = "x86_64")
+            not(target_arch = "x86_64"),
+            not(target_arch = "xtensa")
         ),
         all(target_arch = "aarch64", any(target_os = "macos", target_os = "ios")),
         target_family = "wasm",
@@ -359,7 +378,7 @@ pub struct VaList<'a, 'f: 'a> {
     inner: VaListImpl<'f>,
 
     #[cfg(all(
-        any(target_arch = "aarch64", target_arch = "powerpc", target_arch = "x86_64"),
+        any(target_arch = "aarch64", target_arch = "powerpc", target_arch = "x86_64", target_arch = "xtensa"),
         any(not(target_arch = "aarch64"), not(any(target_os = "macos", target_os = "ios"))),
         not(target_family = "wasm"),
         not(target_arch = "asmjs"),
@@ -371,7 +390,7 @@ pub struct VaList<'a, 'f: 'a> {
 }
 
 #[cfg(any(
-    all(not(target_arch = "aarch64"), not(target_arch = "powerpc"), not(target_arch = "x86_64")),
+    all(not(target_arch = "aarch64"), not(target_arch = "powerpc"), not(target_arch = "x86_64"), not(target_arch = "xtensa")),
     all(target_arch = "aarch64", any(target_os = "macos", target_os = "ios")),
     target_family = "wasm",
     target_arch = "asmjs",
@@ -392,7 +411,7 @@ impl<'f> VaListImpl<'f> {
 }
 
 #[cfg(all(
-    any(target_arch = "aarch64", target_arch = "powerpc", target_arch = "x86_64"),
+    any(target_arch = "aarch64", target_arch = "powerpc", target_arch = "x86_64", target_arch = "xtensa"),
     any(not(target_arch = "aarch64"), not(any(target_os = "macos", target_os = "ios"))),
     not(target_family = "wasm"),
     not(target_arch = "asmjs"),