Auto merge of #115685 - matthiaskrgr:rollup-t31gowy, r=matthiaskrgr

Rollup of 5 pull requests

Successful merges:

 - #113807 (Tests crash from inappropriate use of common linkage)
 - #115358 (debuginfo: add compiler option to allow compressed debuginfo sections)
 - #115630 (Dont suggest use between `use` and cfg attr)
 - #115662 (Improve "associated type not found" diagnostics)
 - #115673 (Fix sanitize/cfg.rs test)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_codegen_llvm/messages.ftl

@@ -83,6 +83,8 @@ codegen_llvm_unknown_ctarget_feature_prefix =
     unknown feature specified for `-Ctarget-feature`: `{$feature}`
     .note = features must begin with a `+` to enable or `-` to disable it
 
+codegen_llvm_unknown_debuginfo_compression = unknown debuginfo compression algorithm {$algorithm} - will fall back to uncompressed debuginfo
+
 codegen_llvm_write_bytecode = failed to write bytecode to {$path}: {$err}
 
 codegen_llvm_write_ir = failed to write LLVM IR to {$path}

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -5,13 +5,17 @@ use crate::back::profiling::{
 use crate::base;
 use crate::common;
 use crate::errors::{
-    CopyBitcode, FromLlvmDiag, FromLlvmOptimizationDiag, LlvmError, WithLlvmError, WriteBytecode,
+    CopyBitcode, FromLlvmDiag, FromLlvmOptimizationDiag, LlvmError, UnknownCompression,
+    WithLlvmError, WriteBytecode,
 };
 use crate::llvm::{self, DiagnosticInfo, PassManager};
 use crate::llvm_util;
 use crate::type_::Type;
 use crate::LlvmCodegenBackend;
 use crate::ModuleLlvm;
+use llvm::{
+    LLVMRustLLVMHasZlibCompressionForDebugSymbols, LLVMRustLLVMHasZstdCompressionForDebugSymbols,
+};
 use rustc_codegen_ssa::back::link::ensure_removed;
 use rustc_codegen_ssa::back::write::{
     BitcodeSection, CodegenContext, EmitObj, ModuleConfig, TargetMachineFactoryConfig,
@@ -234,6 +238,22 @@ pub fn target_machine_factory(
         args_cstr_buff
     };
 
+    let debuginfo_compression = sess.opts.debuginfo_compression.to_string();
+    match sess.opts.debuginfo_compression {
+        rustc_session::config::DebugInfoCompression::Zlib => {
+            if !unsafe { LLVMRustLLVMHasZlibCompressionForDebugSymbols() } {
+                sess.emit_warning(UnknownCompression { algorithm: "zlib" });
+            }
+        }
+        rustc_session::config::DebugInfoCompression::Zstd => {
+            if !unsafe { LLVMRustLLVMHasZstdCompressionForDebugSymbols() } {
+                sess.emit_warning(UnknownCompression { algorithm: "zstd" });
+            }
+        }
+        rustc_session::config::DebugInfoCompression::None => {}
+    };
+    let debuginfo_compression = SmallCStr::new(&debuginfo_compression);
+
     Arc::new(move |config: TargetMachineFactoryConfig| {
         let split_dwarf_file =
             path_mapping.map_prefix(config.split_dwarf_file.unwrap_or_default()).0;
@@ -259,6 +279,7 @@ pub fn target_machine_factory(
                 relax_elf_relocations,
                 use_init_array,
                 split_dwarf_file.as_ptr(),
+                debuginfo_compression.as_ptr(),
                 force_emulated_tls,
                 args_cstr_buff.as_ptr() as *const c_char,
                 args_cstr_buff.len(),

compiler/rustc_codegen_llvm/src/errors.rs

@@ -226,3 +226,9 @@ pub(crate) struct WriteBytecode<'a> {
 pub(crate) struct CopyBitcode {
     pub err: std::io::Error,
 }
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_unknown_debuginfo_compression)]
+pub struct UnknownCompression {
+    pub algorithm: &'static str,
+}

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -2131,6 +2131,7 @@ extern "C" {
         RelaxELFRelocations: bool,
         UseInitArray: bool,
         SplitDwarfFile: *const c_char,
+        DebugInfoCompression: *const c_char,
         ForceEmulatedTls: bool,
         ArgsCstrBuff: *const c_char,
         ArgsCstrBuffLen: usize,
@@ -2366,6 +2367,10 @@ extern "C" {
 
     pub fn LLVMRustIsBitcode(ptr: *const u8, len: usize) -> bool;
 
+    pub fn LLVMRustLLVMHasZlibCompressionForDebugSymbols() -> bool;
+
+    pub fn LLVMRustLLVMHasZstdCompressionForDebugSymbols() -> bool;
+
     pub fn LLVMRustGetSymbols(
         buf_ptr: *const u8,
         buf_len: usize,