Feat: make cg_ssa get_param borrow the builder mutable

Author: RDambrosio016

compiler/rustc_codegen_gcc/src/abi.rs

@@ -14,7 +14,7 @@ impl<'a, 'gcc, 'tcx> AbiBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
         // TODO(antoyo)
     }
 
-    fn get_param(&self, index: usize) -> Self::Value {
+    fn get_param(&mut self, index: usize) -> Self::Value {
         self.cx.current_func.borrow().expect("current func")
             .get_param(index as i32)
             .to_rvalue()

compiler/rustc_codegen_llvm/src/abi.rs

@@ -607,7 +607,7 @@ impl AbiBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
         fn_abi.apply_attrs_callsite(self, callsite)
     }
 
-    fn get_param(&self, index: usize) -> Self::Value {
+    fn get_param(&mut self, index: usize) -> Self::Value {
         llvm::get_param(self.llfn(), index as c_uint)
     }
 }

compiler/rustc_codegen_ssa/src/traits/abi.rs

@@ -4,5 +4,5 @@ use rustc_target::abi::call::FnAbi;
 
 pub trait AbiBuilderMethods<'tcx>: BackendTypes {
     fn apply_attrs_callsite(&mut self, fn_abi: &FnAbi<'tcx, Ty<'tcx>>, callsite: Self::Value);
-    fn get_param(&self, index: usize) -> Self::Value;
+    fn get_param(&mut self, index: usize) -> Self::Value;
 }