New signature of get_fn_addr, teach Rust how to sign fn pointers

Allow PAC metadata to be passed to `get_fn_addr` and related API
changes.

Author: jchlanda

src/common.rs

@@ -2,7 +2,8 @@ use gccjit::{LValue, RValue, ToRValue, Type};
 use rustc_abi::Primitive::Pointer;
 use rustc_abi::{self as abi, HasDataLayout};
 use rustc_codegen_ssa::traits::{
-    BaseTypeCodegenMethods, ConstCodegenMethods, MiscCodegenMethods, StaticCodegenMethods,
+    BaseTypeCodegenMethods, ConstCodegenMethods, MiscCodegenMethods, PacMetadata,
+    StaticCodegenMethods,
 };
 use rustc_middle::mir::Mutability;
 use rustc_middle::mir::interpret::{GlobalAlloc, PointerArithmetic, Scalar};
@@ -229,7 +230,13 @@ impl<'gcc, 'tcx> ConstCodegenMethods for CodegenCx<'gcc, 'tcx> {
         None
     }
 
-    fn scalar_to_backend(&self, cv: Scalar, layout: abi::Scalar, ty: Type<'gcc>) -> RValue<'gcc> {
+    fn scalar_to_backend_with_pac(
+        &self,
+        cv: Scalar,
+        layout: abi::Scalar,
+        ty: Type<'gcc>,
+        _pac: Option<PacMetadata>,
+    ) -> RValue<'gcc> {
         let bitsize = if layout.is_bool() { 1 } else { layout.size(self).bits() };
         match cv {
             Scalar::Int(int) => {
@@ -278,7 +285,7 @@ impl<'gcc, 'tcx> ConstCodegenMethods for CodegenCx<'gcc, 'tcx> {
                         }
                         value
                     }
-                    GlobalAlloc::Function { instance, .. } => self.get_fn_addr(instance),
+                    GlobalAlloc::Function { instance, .. } => self.get_fn_addr(instance, None),
                     GlobalAlloc::VTable(ty, dyn_ty) => {
                         let alloc = self
                             .tcx

src/context.rs

@@ -5,7 +5,9 @@ use gccjit::{Block, CType, Context, Function, FunctionType, LValue, Location, RV
 use rustc_abi::{Align, HasDataLayout, PointeeInfo, Size, TargetDataLayout, VariantIdx};
 use rustc_codegen_ssa::base::wants_msvc_seh;
 use rustc_codegen_ssa::errors as ssa_errors;
-use rustc_codegen_ssa::traits::{BackendTypes, BaseTypeCodegenMethods, MiscCodegenMethods};
+use rustc_codegen_ssa::traits::{
+    BackendTypes, BaseTypeCodegenMethods, MiscCodegenMethods, PacMetadata,
+};
 use rustc_data_structures::base_n::{ALPHANUMERIC_ONLY, ToBaseN};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_middle::mir::interpret::Allocation;
@@ -398,7 +400,7 @@ impl<'gcc, 'tcx> MiscCodegenMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
         get_fn(self, instance)
     }
 
-    fn get_fn_addr(&self, instance: Instance<'tcx>) -> RValue<'gcc> {
+    fn get_fn_addr(&self, instance: Instance<'tcx>, _pac: Option<PacMetadata>) -> RValue<'gcc> {
         let func_name = self.tcx.symbol_name(instance).name;
 
         let func = if let Some(variable) = self.get_declared_value(func_name) {