Rollup merge of rust-lang#137247 - dpaoliello:cleanllvm, r=Zalathar

cg_llvm: Reduce the visibility of types, modules and using declarations in `rustc_codegen_llvm`.

Final part of rust-lang#135502

Reduces the visibility of types, modules and using declarations in the `rustc_codegen_llvm` to private or `pub(crate)` where possible, and marks unused fields and enum entries with `#[expect(dead_code)]`.

r? `@Zalathar`

Author: matthiaskrgr

compiler/rustc_codegen_llvm/src/lib.rs

@@ -30,7 +30,7 @@ use std::mem::ManuallyDrop;
 use back::owned_target_machine::OwnedTargetMachine;
 use back::write::{create_informational_target_machine, create_target_machine};
 use errors::{AutoDiffWithoutLTO, ParseTargetMachineConfig};
-pub(crate) use llvm_util::target_features_cfg;
+use llvm_util::target_features_cfg;
 use rustc_ast::expand::allocator::AllocatorKind;
 use rustc_ast::expand::autodiff_attrs::AutoDiffItem;
 use rustc_codegen_ssa::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule};
@@ -72,9 +72,7 @@ mod debuginfo;
 mod declare;
 mod errors;
 mod intrinsic;
-// FIXME(Zalathar): Fix all the unreachable-pub warnings that would occur if
-// this isn't pub, then make it not pub.
-pub mod llvm;
+mod llvm;
 mod llvm_util;
 mod mono_item;
 mod type_;

compiler/rustc_codegen_llvm/src/llvm/archive_ro.rs

@@ -5,17 +5,17 @@ use std::{slice, str};
 
 use rustc_fs_util::path_to_c_string;
 
-pub struct ArchiveRO {
+pub(crate) struct ArchiveRO {
     pub raw: &'static mut super::Archive,
 }
 
 unsafe impl Send for ArchiveRO {}
 
-pub struct Iter<'a> {
+pub(crate) struct Iter<'a> {
     raw: &'a mut super::ArchiveIterator<'a>,
 }
 
-pub struct Child<'a> {
+pub(crate) struct Child<'a> {
     pub raw: &'a mut super::ArchiveChild<'a>,
 }
 

compiler/rustc_codegen_llvm/src/llvm/diagnostic.rs

@@ -3,13 +3,13 @@
 use libc::c_uint;
 use rustc_span::InnerSpan;
 
-pub use self::Diagnostic::*;
-pub use self::OptimizationDiagnosticKind::*;
+pub(crate) use self::Diagnostic::*;
+use self::OptimizationDiagnosticKind::*;
 use super::{DiagnosticInfo, SMDiagnostic};
 use crate::value::Value;
 
 #[derive(Copy, Clone, Debug)]
-pub enum OptimizationDiagnosticKind {
+pub(crate) enum OptimizationDiagnosticKind {
     OptimizationRemark,
     OptimizationMissed,
     OptimizationAnalysis,
@@ -19,9 +19,10 @@ pub enum OptimizationDiagnosticKind {
     OptimizationRemarkOther,
 }
 
-pub struct OptimizationDiagnostic<'ll> {
+pub(crate) struct OptimizationDiagnostic<'ll> {
     pub kind: OptimizationDiagnosticKind,
     pub pass_name: String,
+    #[expect(dead_code)]
     pub function: &'ll Value,
     pub line: c_uint,
     pub column: c_uint,
@@ -73,14 +74,14 @@ impl<'ll> OptimizationDiagnostic<'ll> {
     }
 }
 
-pub struct SrcMgrDiagnostic {
+pub(crate) struct SrcMgrDiagnostic {
     pub level: super::DiagnosticLevel,
     pub message: String,
     pub source: Option<(String, Vec<InnerSpan>)>,
 }
 
 impl SrcMgrDiagnostic {
-    pub unsafe fn unpack(diag: &SMDiagnostic) -> SrcMgrDiagnostic {
+    pub(crate) unsafe fn unpack(diag: &SMDiagnostic) -> SrcMgrDiagnostic {
         // Recover the post-substitution assembly code from LLVM for better
         // diagnostics.
         let mut have_source = false;
@@ -120,7 +121,7 @@ impl SrcMgrDiagnostic {
 }
 
 #[derive(Clone)]
-pub struct InlineAsmDiagnostic {
+pub(crate) struct InlineAsmDiagnostic {
     pub level: super::DiagnosticLevel,
     pub cookie: u64,
     pub message: String,
@@ -158,19 +159,20 @@ impl InlineAsmDiagnostic {
     }
 }
 
-pub enum Diagnostic<'ll> {
+pub(crate) enum Diagnostic<'ll> {
     Optimization(OptimizationDiagnostic<'ll>),
     InlineAsm(InlineAsmDiagnostic),
     PGO(&'ll DiagnosticInfo),
     Linker(&'ll DiagnosticInfo),
     Unsupported(&'ll DiagnosticInfo),
 
     /// LLVM has other types that we do not wrap here.
+    #[expect(dead_code)]
     UnknownDiagnostic(&'ll DiagnosticInfo),
 }
 
 impl<'ll> Diagnostic<'ll> {
-    pub unsafe fn unpack(di: &'ll DiagnosticInfo) -> Self {
+    pub(crate) unsafe fn unpack(di: &'ll DiagnosticInfo) -> Self {
         use super::DiagnosticKind as Dk;
 
         unsafe {

compiler/rustc_codegen_llvm/src/llvm/enzyme_ffi.rs

@@ -30,7 +30,7 @@ unsafe extern "C" {
 
 #[repr(C)]
 #[derive(Copy, Clone, PartialEq)]
-pub enum LLVMRustVerifierFailureAction {
+pub(crate) enum LLVMRustVerifierFailureAction {
     LLVMAbortProcessAction = 0,
     LLVMPrintMessageAction = 1,
     LLVMReturnStatusAction = 2,