Unknown -> Unsupported compression algorithm

Both zstd and zlib are *known* compression algorithms, they just may not
be supported by the backend. We shouldn't mislead users into e.g.
thinking they made a typo.

Author: Mark-Simulacrum

compiler/rustc_codegen_llvm/messages.ftl

@@ -61,7 +61,7 @@ codegen_llvm_symbol_already_defined =
 codegen_llvm_target_machine = could not create LLVM TargetMachine for triple: {$triple}
 codegen_llvm_target_machine_with_llvm_err = could not create LLVM TargetMachine for triple: {$triple}: {$llvm_err}
 
-codegen_llvm_unknown_debuginfo_compression = unknown debuginfo compression algorithm {$algorithm} - will fall back to uncompressed debuginfo
+codegen_llvm_unsupported_debuginfo_compression = unsupported debuginfo compression algorithm {$algorithm} - will fall back to uncompressed debuginfo
 
 codegen_llvm_write_bytecode = failed to write bytecode to {$path}: {$err}
 

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -38,7 +38,7 @@ use crate::builder::SBuilder;
 use crate::builder::gpu_offload::scalar_width;
 use crate::common::AsCCharPtr;
 use crate::errors::{
-    CopyBitcode, FromLlvmDiag, FromLlvmOptimizationDiag, LlvmError, UnknownCompression,
+    CopyBitcode, FromLlvmDiag, FromLlvmOptimizationDiag, LlvmError, UnsupportedCompression,
     WithLlvmError, WriteBytecode,
 };
 use crate::llvm::diagnostic::OptimizationDiagnosticKind::*;
@@ -259,15 +259,15 @@ pub(crate) fn target_machine_factory(
             if llvm::LLVMRustLLVMHasZlibCompression() {
                 llvm::CompressionKind::Zlib
             } else {
-                sess.dcx().emit_warn(UnknownCompression { algorithm: "zlib" });
+                sess.dcx().emit_warn(UnsupportedCompression { algorithm: "zlib" });
                 llvm::CompressionKind::None
             }
         }
         config::DebugInfoCompression::Zstd => {
             if llvm::LLVMRustLLVMHasZstdCompression() {
                 llvm::CompressionKind::Zstd
             } else {
-                sess.dcx().emit_warn(UnknownCompression { algorithm: "zstd" });
+                sess.dcx().emit_warn(UnsupportedCompression { algorithm: "zstd" });
                 llvm::CompressionKind::None
             }
         }

compiler/rustc_codegen_llvm/src/errors.rs

@@ -169,8 +169,8 @@ pub(crate) struct CopyBitcode {
 }
 
 #[derive(Diagnostic)]
-#[diag(codegen_llvm_unknown_debuginfo_compression)]
-pub(crate) struct UnknownCompression {
+#[diag(codegen_llvm_unsupported_debuginfo_compression)]
+pub(crate) struct UnsupportedCompression {
     pub algorithm: &'static str,
 }
 

tests/run-make/compressed-debuginfo/rmake.rs

@@ -23,7 +23,7 @@ fn check_compression(compression: &str, to_find: &str) {
         } else {
             assert_contains(
                 stderr,
-                format!("unknown debuginfo compression algorithm {compression}"),
+                format!("unsupported debuginfo compression algorithm {compression}"),
             );
         }
     });