Rollup merge of rust-lang#136881 - dpaoliello:cleanllvm3, r=Zalathar

cg_llvm: Reduce visibility of all functions in the llvm module

Next part of rust-lang#135502

This reduces the visibility of all functions in the `llvm` module to `pub(crate)` and marks the `enzyme_ffi` modules with `#![expect(dead_code)]` (as previously discussed: <rust-lang#135502 (comment)>).

r? ``@Zalathar``

Author: jhpratt

compiler/rustc_codegen_llvm/src/llvm/archive_ro.rs

@@ -26,7 +26,7 @@ impl ArchiveRO {
     ///
     /// If this archive is used with a mutable method, then an error will be
     /// raised.
-    pub fn open(dst: &Path) -> Result<ArchiveRO, String> {
+    pub(crate) fn open(dst: &Path) -> Result<ArchiveRO, String> {
         unsafe {
             let s = path_to_c_string(dst);
             let ar = super::LLVMRustOpenArchive(s.as_ptr()).ok_or_else(|| {
@@ -36,7 +36,7 @@ impl ArchiveRO {
         }
     }
 
-    pub fn iter(&self) -> Iter<'_> {
+    pub(crate) fn iter(&self) -> Iter<'_> {
         unsafe { Iter { raw: super::LLVMRustArchiveIteratorNew(self.raw) } }
     }
 }
@@ -71,7 +71,7 @@ impl<'a> Drop for Iter<'a> {
 }
 
 impl<'a> Child<'a> {
-    pub fn name(&self) -> Option<&'a str> {
+    pub(crate) fn name(&self) -> Option<&'a str> {
         unsafe {
             let mut name_len = 0;
             let name_ptr = super::LLVMRustArchiveChildName(self.raw, &mut name_len);

compiler/rustc_codegen_llvm/src/llvm/enzyme_ffi.rs

@@ -1,4 +1,5 @@
 #![allow(non_camel_case_types)]
+#![expect(dead_code)]
 
 use libc::{c_char, c_uint};
 
@@ -8,23 +9,23 @@ use crate::llvm::Bool;
 #[link(name = "llvm-wrapper", kind = "static")]
 extern "C" {
     // Enzyme
-    pub fn LLVMRustHasMetadata(I: &Value, KindID: c_uint) -> bool;
-    pub fn LLVMRustEraseInstUntilInclusive(BB: &BasicBlock, I: &Value);
-    pub fn LLVMRustGetLastInstruction<'a>(BB: &BasicBlock) -> Option<&'a Value>;
-    pub fn LLVMRustDIGetInstMetadata(I: &Value) -> Option<&Metadata>;
-    pub fn LLVMRustEraseInstFromParent(V: &Value);
-    pub fn LLVMRustGetTerminator<'a>(B: &BasicBlock) -> &'a Value;
-    pub fn LLVMRustVerifyFunction(V: &Value, action: LLVMRustVerifierFailureAction) -> Bool;
+    pub(crate) fn LLVMRustHasMetadata(I: &Value, KindID: c_uint) -> bool;
+    pub(crate) fn LLVMRustEraseInstUntilInclusive(BB: &BasicBlock, I: &Value);
+    pub(crate) fn LLVMRustGetLastInstruction<'a>(BB: &BasicBlock) -> Option<&'a Value>;
+    pub(crate) fn LLVMRustDIGetInstMetadata(I: &Value) -> Option<&Metadata>;
+    pub(crate) fn LLVMRustEraseInstFromParent(V: &Value);
+    pub(crate) fn LLVMRustGetTerminator<'a>(B: &BasicBlock) -> &'a Value;
+    pub(crate) fn LLVMRustVerifyFunction(V: &Value, action: LLVMRustVerifierFailureAction) -> Bool;
 }
 
 extern "C" {
     // Enzyme
-    pub fn LLVMDumpModule(M: &Module);
-    pub fn LLVMDumpValue(V: &Value);
-    pub fn LLVMGetFunctionCallConv(F: &Value) -> c_uint;
-    pub fn LLVMGetReturnType(T: &Type) -> &Type;
-    pub fn LLVMGetParams(Fnc: &Value, parms: *mut &Value);
-    pub fn LLVMGetNamedFunction(M: &Module, Name: *const c_char) -> Option<&Value>;
+    pub(crate) fn LLVMDumpModule(M: &Module);
+    pub(crate) fn LLVMDumpValue(V: &Value);
+    pub(crate) fn LLVMGetFunctionCallConv(F: &Value) -> c_uint;
+    pub(crate) fn LLVMGetReturnType(T: &Type) -> &Type;
+    pub(crate) fn LLVMGetParams(Fnc: &Value, parms: *mut &Value);
+    pub(crate) fn LLVMGetNamedFunction(M: &Module, Name: *const c_char) -> Option<&Value>;
 }
 
 #[repr(C)]