Change FnAbi::fixed_count to a u32.

compiler/rustc_codegen_llvm/src/abi.rs

@@ -325,7 +325,8 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
     fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
         // Ignore "extra" args from the call site for C variadic functions.
         // Only the "fixed" args are part of the LLVM function signature.
-        let args = if self.c_variadic { &self.args[..self.fixed_count] } else { &self.args };
+        let args =
+            if self.c_variadic { &self.args[..self.fixed_count as usize] } else { &self.args };
 
         let args_capacity: usize = args.iter().map(|arg|
             if arg.pad.is_some() { 1 } else { 0 } +

compiler/rustc_middle/src/ty/layout.rs

@@ -3262,7 +3262,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
                 .map(|(i, ty)| arg_of(ty, Some(i)))
                 .collect::<Result<_, _>>()?,
             c_variadic: sig.c_variadic,
-            fixed_count: inputs.len(),
+            fixed_count: inputs.len() as u32,
             conv,
             can_unwind: fn_can_unwind(self.tcx(), fn_def_id, sig.abi),
         };

compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs

@@ -888,7 +888,7 @@ pub fn typeid_for_fnabi<'tcx>(
             typeid.push('v');
         }
     } else {
-        for n in 0..fn_abi.fixed_count {
+        for n in 0..fn_abi.fixed_count as usize {
             let ty = transform_ty(tcx, fn_abi.args[n].layout.ty, transform_ty_options);
             typeid.push_str(&encode_ty(tcx, ty, &mut dict, encode_ty_options));
         }

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

@@ -625,7 +625,7 @@ pub struct FnAbi<'a, Ty> {
     ///
     /// Should only be different from args.len() when c_variadic is true.
     /// This can be used to know whether an argument is variadic or not.
-    pub fixed_count: usize,
+    pub fixed_count: u32,
 
     pub conv: Conv,
 
@@ -738,5 +738,5 @@ mod size_asserts {
     use rustc_data_structures::static_assert_size;
     // These are in alphabetical order, which is easy to maintain.
     static_assert_size!(ArgAbi<'_, usize>, 72);
-    static_assert_size!(FnAbi<'_, usize>, 112);
+    static_assert_size!(FnAbi<'_, usize>, 104);
 }

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

@@ -340,7 +340,7 @@ where
             arg,
             xlen,
             flen,
-            i >= fn_abi.fixed_count,
+            i >= fn_abi.fixed_count as usize,
             &mut avail_gprs,
             &mut avail_fprs,
         );