Stabilize -Zdebuginfo-compression as -Cdebuginfo-compression

Author: wesleywiser

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -250,7 +250,7 @@ pub(crate) fn target_machine_factory(
 
     let use_emulated_tls = matches!(sess.tls_model(), TlsModel::Emulated);
 
-    let debuginfo_compression = match sess.opts.unstable_opts.debuginfo_compression {
+    let debuginfo_compression = match sess.debuginfo_compression() {
         config::DebugInfoCompression::None => llvm::CompressionKind::None,
         config::DebugInfoCompression::Zlib => {
             if llvm::LLVMRustLLVMHasZlibCompression() {

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -756,7 +756,7 @@ impl<'a> Linker for GccLinker<'a> {
                 self.link_arg("--strip-all");
             }
         }
-        match self.sess.opts.unstable_opts.debuginfo_compression {
+        match self.sess.debuginfo_compression() {
             config::DebugInfoCompression::None => {}
             config::DebugInfoCompression::Zlib => {
                 self.link_arg("--compress-debug-sections=zlib");

compiler/rustc_codegen_ssa/src/traits/backend.rs

@@ -81,7 +81,7 @@ pub trait CodegenBackend {
     /// Value printed by `--print=backend-has-zstd`.
     ///
     /// Used by compiletest to determine whether tests involving zstd compression
-    /// (e.g. `-Zdebuginfo-compression=zstd`) should be executed or skipped.
+    /// (e.g. `-Cdebuginfo-compression=zstd`) should be executed or skipped.
     fn has_zstd(&self) -> bool {
         false
     }

compiler/rustc_session/src/options.rs

@@ -1357,15 +1357,15 @@ pub mod parse {
     }
 
     pub(crate) fn parse_debuginfo_compression(
-        slot: &mut DebugInfoCompression,
+        slot: &mut Option<DebugInfoCompression>,
         v: Option<&str>,
     ) -> bool {
-        match v {
-            Some("none") => *slot = DebugInfoCompression::None,
-            Some("zlib") => *slot = DebugInfoCompression::Zlib,
-            Some("zstd") => *slot = DebugInfoCompression::Zstd,
+        *slot = Some(match v {
+            Some("none") => DebugInfoCompression::None,
+            Some("zlib") => DebugInfoCompression::Zlib,
+            Some("zstd") => DebugInfoCompression::Zstd,
             _ => return false,
-        };
+        });
         true
     }
 
@@ -2101,6 +2101,9 @@ options! {
     debuginfo: DebugInfo = (DebugInfo::None, parse_debuginfo, [TRACKED],
         "debug info emission level (0-2, none, line-directives-only, \
         line-tables-only, limited, or full; default: 0)"),
+    #[rustc_lint_opt_deny_field_access("use `Session::debuginfo_compression` instead of this field")]
+    debuginfo_compression: Option<DebugInfoCompression> = (None, parse_debuginfo_compression, [TRACKED],
+        "compress debug info sections (none, zlib, zstd, default: none)"),
     default_linker_libraries: bool = (false, parse_bool, [UNTRACKED],
         "allow the linker to link its default libraries (default: no)"),
     dlltool: Option<PathBuf> = (None, parse_opt_pathbuf, [UNTRACKED],
@@ -2291,7 +2294,8 @@ options! {
         "emit discriminators and other data necessary for AutoFDO"),
     debug_info_type_line_numbers: bool = (false, parse_bool, [TRACKED],
         "emit type and line information for additional data types (default: no)"),
-    debuginfo_compression: DebugInfoCompression = (DebugInfoCompression::None, parse_debuginfo_compression, [TRACKED],
+    #[rustc_lint_opt_deny_field_access("use `Session::debuginfo_compression` instead of this field")]
+    debuginfo_compression: Option<DebugInfoCompression> = (None, parse_debuginfo_compression, [TRACKED],
         "compress debug info sections (none, zlib, zstd, default: none)"),
     deduplicate_diagnostics: bool = (true, parse_bool, [UNTRACKED],
         "deduplicate identical diagnostics (default: yes)"),

compiler/rustc_session/src/session.rs

@@ -37,8 +37,9 @@ use rustc_target::spec::{
 use crate::code_stats::CodeStats;
 pub use crate::code_stats::{DataTypeKind, FieldInfo, FieldKind, SizeKind, VariantInfo};
 use crate::config::{
-    self, CoverageLevel, CoverageOptions, CrateType, DebugInfo, ErrorOutputType, FunctionReturn,
-    Input, InstrumentCoverage, OptLevel, OutFileName, OutputType, SwitchWithOptPath,
+    self, CoverageLevel, CoverageOptions, CrateType, DebugInfo, DebugInfoCompression,
+    ErrorOutputType, FunctionReturn, Input, InstrumentCoverage, OptLevel, OutFileName, OutputType,
+    SwitchWithOptPath,
 };
 use crate::filesearch::FileSearch;
 use crate::lint::LintId;
@@ -713,6 +714,14 @@ impl Session {
             .unwrap_or(self.target.default_dwarf_version)
     }
 
+    pub fn debuginfo_compression(&self) -> DebugInfoCompression {
+        self.opts
+            .cg
+            .debuginfo_compression
+            .or(self.opts.unstable_opts.debuginfo_compression)
+            .unwrap_or(DebugInfoCompression::None)
+    }
+
     pub fn stack_protector(&self) -> StackProtector {
         if self.target.options.supports_stack_protector {
             self.opts.unstable_opts.stack_protector

src/doc/rustc/src/codegen-options/index.md

@@ -91,6 +91,26 @@ following values:
 
 Note: The [`-g` flag][option-g-debug] is an alias for `-C debuginfo=2`.
 
+## debuginfo-compression
+
+This flag controls how debug information is compressed. It takes one of the
+following values:
+
+* `none`: debug info is not compressed (the default).
+* `zlib`: debug info is compressed using zlib.
+* `zstd`: debug info is compressed using zstd.
+
+Tools which read debug info such as debuggers and profilers must support the
+compression algorithm or they will be unable to process the debug info. `zlib`
+compression tends to be well supported by Linux tools but `zstd` may require
+very recent versions of such tools.
+
+Compressing debug info can improve binary size but will increase time and memory
+used during compilation.
+
+This flag is ignored by the compiler if the target does not support the specified
+compression algorithm.
+
 ## default-linker-libraries
 
 This flag controls whether or not the linker includes its default libraries.

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

@@ -13,7 +13,7 @@ use run_make_support::{Rustc, llvm_readobj, run_in_tmpdir};
 fn check_compression(compression: &str, to_find: &str) {
     // check compressed debug sections via rustc flag
     prepare_and_check(to_find, |rustc| {
-        rustc.arg(&format!("-Zdebuginfo-compression={compression}"))
+        rustc.arg(&format!("-Cdebuginfo-compression={compression}"))
     });
 
     // check compressed debug sections via rust-lld flag

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

@@ -14,7 +14,7 @@ fn check_compression(compression: &str, to_find: &str) {
             .crate_type("lib")
             .emit("obj")
             .arg("-Cdebuginfo=full")
-            .arg(&format!("-Zdebuginfo-compression={compression}"))
+            .arg(&format!("-Cdebuginfo-compression={compression}"))
             .input("foo.rs")
             .run();
         let stderr = out.stderr_utf8();