Rollup merge of #137549 - oli-obk:llvm-ffi, r=davidtwco

Clean up various LLVM FFI things in codegen_llvm

cc ```@ZuseZ4``` I touched some autodiff parts

The major change of this PR is [bfd88ce](https://github.com/rust-lang/rust/pull/137549/commits/bfd88cead0dd79717f123ad7e9a26ecad88653cb) which makes `CodegenCx` generic just like `GenericBuilder`

The other commits mostly took advantage of the new feature of making extern functions safe, but also just used some wrappers that were already there and shrunk unsafe blocks.

best reviewed commit-by-commit

1 files changed, 3 insertions, 1 deletions

diff --git a/compiler/rustc_codegen_llvm/src/builder/autodiff.rs b/compiler/rustc_codegen_llvm/src/builder/autodiff.rs
index 2c7899975e3..71705ecb4d0 100644
--- a/compiler/rustc_codegen_llvm/src/builder/autodiff.rs
+++ b/compiler/rustc_codegen_llvm/src/builder/autodiff.rs
@@ -3,6 +3,7 @@ use std::ptr;
 use rustc_ast::expand::autodiff_attrs::{AutoDiffAttrs, AutoDiffItem, DiffActivity, DiffMode};
 use rustc_codegen_ssa::ModuleCodegen;
 use rustc_codegen_ssa::back::write::ModuleConfig;
+use rustc_codegen_ssa::traits::BaseTypeCodegenMethods as _;
 use rustc_errors::FatalError;
 use tracing::{debug, trace};
 
@@ -286,7 +287,8 @@ pub(crate) fn differentiate<'ll>(
     }
 
     let diag_handler = cgcx.create_dcx();
-    let cx = SimpleCx { llmod: module.module_llvm.llmod(), llcx: module.module_llvm.llcx };
+
+    let cx = SimpleCx::new(module.module_llvm.llmod(), module.module_llvm.llcx, cgcx.pointer_size);
 
     // First of all, did the user try to use autodiff without using the -Zautodiff=Enable flag?
     if !diff_items.is_empty()