Rollup merge of rust-lang#136993 - dpaoliello:cleanllvm4, r=workingjubilee

[cg_llvm] Remove dead error message

Part of rust-lang#135502

Discovered a dead error message in rustc_codegen_llvm, so removing it.

r? ``@Zalathar``

Author: workingjubilee

compiler/rustc_codegen_llvm/messages.ftl

@@ -38,9 +38,6 @@ codegen_llvm_lto_proc_macro = lto cannot be used for `proc-macro` crate type wit
 codegen_llvm_mismatch_data_layout =
     data-layout for target `{$rustc_target}`, `{$rustc_layout}`, differs from LLVM target's `{$llvm_target}` default layout, `{$llvm_layout}`
 
-codegen_llvm_multiple_source_dicompileunit = multiple source DICompileUnits found
-codegen_llvm_multiple_source_dicompileunit_with_llvm_err = multiple source DICompileUnits found: {$llvm_err}
-
 codegen_llvm_parse_bitcode = failed to parse bitcode for LTO module
 codegen_llvm_parse_bitcode_with_llvm_err = failed to parse bitcode for LTO module: {$llvm_err}
 

compiler/rustc_codegen_llvm/src/errors.rs

@@ -131,8 +131,6 @@ pub enum LlvmError<'a> {
     LoadBitcode { name: CString },
     #[diag(codegen_llvm_write_thinlto_key)]
     WriteThinLtoKey { err: std::io::Error },
-    #[diag(codegen_llvm_multiple_source_dicompileunit)]
-    MultipleSourceDiCompileUnit,
     #[diag(codegen_llvm_prepare_thin_lto_module)]
     PrepareThinLtoModule,
     #[diag(codegen_llvm_parse_bitcode)]
@@ -155,9 +153,6 @@ impl<G: EmissionGuarantee> Diagnostic<'_, G> for WithLlvmError<'_> {
             PrepareThinLtoContext => fluent::codegen_llvm_prepare_thin_lto_context_with_llvm_err,
             LoadBitcode { .. } => fluent::codegen_llvm_load_bitcode_with_llvm_err,
             WriteThinLtoKey { .. } => fluent::codegen_llvm_write_thinlto_key_with_llvm_err,
-            MultipleSourceDiCompileUnit => {
-                fluent::codegen_llvm_multiple_source_dicompileunit_with_llvm_err
-            }
             PrepareThinLtoModule => fluent::codegen_llvm_prepare_thin_lto_module_with_llvm_err,
             ParseBitcode => fluent::codegen_llvm_parse_bitcode_with_llvm_err,
             PrepareAutoDiff { .. } => fluent::codegen_llvm_prepare_autodiff_with_llvm_err,