Allow named debuginfo options in Cargo.toml

Rustc supports these since rust-lang/rust#109808. It's technically
possible to set a named debuginfo level through `RUSTFLAGS`, but in
practice cargo always passes its own opinion of what the debuginfo level
is, so allow it to be configured through cargo too.

src/cargo/core/compiler/mod.rs

@@ -603,9 +603,13 @@ fn link_targets(cx: &mut Context<'_, '_>, unit: &Unit, fresh: bool) -> CargoResu
         }
 
         if json_messages {
+            let debuginfo = profile.debuginfo.to_option().map(|d| match d.parse() {
+                Ok(n) => machine_message::ArtifactDebuginfo::Int(n),
+                Err(_) => machine_message::ArtifactDebuginfo::Named(d.to_string()),
+            });
             let art_profile = machine_message::ArtifactProfile {
                 opt_level: profile.opt_level.as_str(),
-                debuginfo: profile.debuginfo.to_option(),
+                debuginfo,
                 debug_assertions: profile.debug_assertions,
                 overflow_checks: profile.overflow_checks,
                 test: unit_mode.is_any_test(),

src/cargo/core/profiles.rs

@@ -26,7 +26,9 @@ use crate::core::dependency::Artifact;
 use crate::core::resolver::features::FeaturesFor;
 use crate::core::{PackageId, PackageIdSpec, Resolve, Shell, Target, Workspace};
 use crate::util::interning::InternedString;
-use crate::util::toml::{ProfilePackageSpec, StringOrBool, TomlProfile, TomlProfiles, U32OrBool};
+use crate::util::toml::{
+    ProfilePackageSpec, StringOrBool, TomlProfile, TomlProfiles, U32OrBoolOrString,
+};
 use crate::util::{closest_msg, config, CargoResult, Config};
 use anyhow::{bail, Context as _};
 use std::collections::{BTreeMap, HashMap, HashSet};
@@ -276,15 +278,13 @@ impl Profiles {
         // platform which has a stable `-Csplit-debuginfo` option for rustc,
         // and it's typically much faster than running `dsymutil` on all builds
         // in incremental cases.
-        if let Some(debug) = profile.debuginfo.to_option() {
-            if profile.split_debuginfo.is_none() && debug > 0 {
-                let target = match &kind {
-                    CompileKind::Host => self.rustc_host.as_str(),
-                    CompileKind::Target(target) => target.short_name(),
-                };
-                if target.contains("-apple-") {
-                    profile.split_debuginfo = Some(InternedString::new("unpacked"));
-                }
+        if profile.debuginfo.is_turned_on() && profile.split_debuginfo.is_none() {
+            let target = match &kind {
+                CompileKind::Host => self.rustc_host.as_str(),
+                CompileKind::Target(target) => target.short_name(),
+            };
+            if target.contains("-apple-") {
+                profile.split_debuginfo = Some(InternedString::new("unpacked"));
             }
         }
 
@@ -529,9 +529,12 @@ fn merge_profile(profile: &mut Profile, toml: &TomlProfile) {
         profile.codegen_units = toml.codegen_units;
     }
     match toml.debug {
-        Some(U32OrBool::U32(debug)) => profile.debuginfo = DebugInfo::Explicit(debug),
-        Some(U32OrBool::Bool(true)) => profile.debuginfo = DebugInfo::Explicit(2),
-        Some(U32OrBool::Bool(false)) => profile.debuginfo = DebugInfo::None,
+        Some(U32OrBoolOrString::U32(debug)) => {
+            profile.debuginfo = DebugInfo::Explicit(debug.to_string().into())
+        }
+        Some(U32OrBoolOrString::Bool(true)) => profile.debuginfo = DebugInfo::Explicit("2".into()),
+        Some(U32OrBoolOrString::Bool(false)) => profile.debuginfo = DebugInfo::None,
+        Some(U32OrBoolOrString::String(ref s)) => profile.debuginfo = DebugInfo::Explicit(s.into()),
         None => {}
     }
     if let Some(debug_assertions) = toml.debug_assertions {
@@ -683,7 +686,7 @@ impl Profile {
         Profile {
             name: InternedString::new("dev"),
             root: ProfileRoot::Debug,
-            debuginfo: DebugInfo::Explicit(2),
+            debuginfo: DebugInfo::Explicit("2".into()),
             debug_assertions: true,
             overflow_checks: true,
             incremental: true,
@@ -743,7 +746,7 @@ pub enum DebugInfo {
     /// No debuginfo level was set.
     None,
     /// A debuginfo level that is explicitly set, by a profile or a user.
-    Explicit(u32),
+    Explicit(InternedString),
     /// For internal purposes: a deferred debuginfo level that can be optimized
     /// away, but has this value otherwise.
     ///
@@ -753,22 +756,25 @@ pub enum DebugInfo {
     /// faster to build (see [DebugInfo::weaken]).
     ///
     /// In all other situations, this level value will be the one to use.
-    Deferred(u32),
+    Deferred(InternedString),
 }
 
 impl DebugInfo {
     /// The main way to interact with this debuginfo level, turning it into an Option.
-    pub fn to_option(&self) -> Option<u32> {
+    pub fn to_option(self) -> Option<InternedString> {
         match self {
             DebugInfo::None => None,
-            DebugInfo::Explicit(v) | DebugInfo::Deferred(v) => Some(*v),
+            DebugInfo::Explicit(v) | DebugInfo::Deferred(v) => Some(v),
         }
     }
 
     /// Returns true if the debuginfo level is high enough (at least 1). Helper
     /// for a common operation on the usual `Option` representation.
     pub(crate) fn is_turned_on(&self) -> bool {
-        self.to_option().unwrap_or(0) != 0
+        match self.to_option().as_deref() {
+            None | Some("0") | Some("none") => false,
+            Some(_) => true,
+        }
     }
 
     pub(crate) fn is_deferred(&self) -> bool {

src/cargo/util/machine_message.rs

@@ -55,12 +55,20 @@ impl<'a> Message for Artifact<'a> {
 #[derive(Serialize)]
 pub struct ArtifactProfile {
     pub opt_level: &'static str,
-    pub debuginfo: Option<u32>,
+    pub debuginfo: Option<ArtifactDebuginfo>,
     pub debug_assertions: bool,
     pub overflow_checks: bool,
     pub test: bool,
 }
 
+/// Internally this is just a string, but keep using 0/1/2 as integers for compatibility.
+#[derive(Serialize)]
+#[serde(untagged)]
+pub enum ArtifactDebuginfo {
+    Int(u32),
+    Named(String),
+}
+
 #[derive(Serialize)]
 pub struct BuildScript<'a> {
     pub package_id: PackageId,

src/cargo/util/toml/mod.rs

@@ -443,10 +443,11 @@ impl ser::Serialize for TomlOptLevel {
 }
 
 #[derive(Clone, Debug, Deserialize, Serialize, Eq, PartialEq)]
-#[serde(untagged, expecting = "expected a boolean or an integer")]
-pub enum U32OrBool {
+#[serde(untagged, expecting = "expected a boolean, integer, or string")]
+pub enum U32OrBoolOrString {
     U32(u32),
     Bool(bool),
+    String(String),
 }
 
 #[derive(Deserialize, Serialize, Clone, Debug, Default, Eq, PartialEq)]
@@ -456,7 +457,7 @@ pub struct TomlProfile {
     pub lto: Option<StringOrBool>,
     pub codegen_backend: Option<InternedString>,
     pub codegen_units: Option<u32>,
-    pub debug: Option<U32OrBool>,
+    pub debug: Option<U32OrBoolOrString>,
     pub split_debuginfo: Option<String>,
     pub debug_assertions: Option<bool>,
     pub rpath: Option<bool>,

tests/testsuite/bad_config.rs

@@ -1313,14 +1313,45 @@ fn bad_debuginfo() {
         .file("src/lib.rs", "")
         .build();
 
+    p.cargo("check")
+        .with_status(101)
+        .with_stderr(
+            "\
+[CHECKING] foo v0.0.0 ([CWD])
+error: incorrect value `a` for codegen option `debuginfo` [..]
+
+error: could not compile `foo` (lib) due to previous error
+",
+        )
+        .run();
+}
+
+#[cargo_test]
+fn bad_debuginfo2() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.0"
+                authors = []
+
+                [profile.dev]
+                debug = 3.6
+            "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
     p.cargo("check")
         .with_status(101)
         .with_stderr(
             "\
 error: failed to parse manifest at `[..]`
 
 Caused by:
-  expected a boolean or an integer
+  expected a boolean, integer, or string
   in `profile.dev.debug`
 ",
         )

tests/testsuite/config.rs

@@ -401,7 +401,7 @@ lto = false
             opt_level: Some(cargo_toml::TomlOptLevel("s".to_string())),
             lto: Some(cargo_toml::StringOrBool::Bool(true)),
             codegen_units: Some(5),
-            debug: Some(cargo_toml::U32OrBool::Bool(true)),
+            debug: Some(cargo_toml::U32OrBoolOrString::Bool(true)),
             debug_assertions: Some(true),
             rpath: Some(true),
             panic: Some("abort".to_string()),
@@ -444,15 +444,15 @@ fn profile_env_var_prefix() {
         .build();
     let p: cargo_toml::TomlProfile = config.get("profile.dev").unwrap();
     assert_eq!(p.debug_assertions, None);
-    assert_eq!(p.debug, Some(cargo_toml::U32OrBool::U32(1)));
+    assert_eq!(p.debug, Some(cargo_toml::U32OrBoolOrString::U32(1)));
 
     let config = ConfigBuilder::new()
         .env("CARGO_PROFILE_DEV_DEBUG_ASSERTIONS", "false")
         .env("CARGO_PROFILE_DEV_DEBUG", "1")
         .build();
     let p: cargo_toml::TomlProfile = config.get("profile.dev").unwrap();
     assert_eq!(p.debug_assertions, Some(false));
-    assert_eq!(p.debug, Some(cargo_toml::U32OrBool::U32(1)));
+    assert_eq!(p.debug, Some(cargo_toml::U32OrBoolOrString::U32(1)));
 }
 
 #[cargo_test]
@@ -1511,7 +1511,7 @@ fn all_profile_options() {
         lto: Some(cargo_toml::StringOrBool::String("thin".to_string())),
         codegen_backend: Some(InternedString::new("example")),
         codegen_units: Some(123),
-        debug: Some(cargo_toml::U32OrBool::U32(1)),
+        debug: Some(cargo_toml::U32OrBoolOrString::U32(1)),
         split_debuginfo: Some("packed".to_string()),
         debug_assertions: Some(true),
         rpath: Some(true),

tests/testsuite/profile_config.rs

@@ -436,7 +436,7 @@ fn named_config_profile() {
     assert_eq!(p.name, "foo");
     assert_eq!(p.codegen_units, Some(2)); // "foo" from config
     assert_eq!(p.opt_level, "1"); // "middle" from manifest
-    assert_eq!(p.debuginfo.to_option(), Some(1)); // "bar" from config
+    assert_eq!(p.debuginfo.to_option(), Some("1".into())); // "bar" from config
     assert_eq!(p.debug_assertions, true); // "dev" built-in (ignore build-override)
     assert_eq!(p.overflow_checks, true); // "dev" built-in (ignore package override)
 
@@ -445,7 +445,7 @@ fn named_config_profile() {
     assert_eq!(bo.name, "foo");
     assert_eq!(bo.codegen_units, Some(6)); // "foo" build override from config
     assert_eq!(bo.opt_level, "0"); // default to zero
-    assert_eq!(bo.debuginfo.to_option(), Some(1)); // SAME as normal
+    assert_eq!(bo.debuginfo.to_option(), Some("1".into())); // SAME as normal
     assert_eq!(bo.debug_assertions, false); // "foo" build override from manifest
     assert_eq!(bo.overflow_checks, true); // SAME as normal
 
@@ -454,7 +454,7 @@ fn named_config_profile() {
     assert_eq!(po.name, "foo");
     assert_eq!(po.codegen_units, Some(7)); // "foo" package override from config
     assert_eq!(po.opt_level, "1"); // SAME as normal
-    assert_eq!(po.debuginfo.to_option(), Some(1)); // SAME as normal
+    assert_eq!(po.debuginfo.to_option(), Some("1".into())); // SAME as normal
     assert_eq!(po.debug_assertions, true); // SAME as normal
     assert_eq!(po.overflow_checks, false); // "middle" package override from manifest
 }

tests/testsuite/unit_graph.rs

@@ -72,7 +72,7 @@ fn simple() {
                     "codegen_backend": null,
                     "codegen_units": null,
                     "debug_assertions": true,
-                    "debuginfo": 2,
+                    "debuginfo": "2",
                     "incremental": false,
                     "lto": "false",
                     "name": "dev",
@@ -117,7 +117,7 @@ fn simple() {
                     "codegen_backend": null,
                     "codegen_units": null,
                     "debug_assertions": true,
-                    "debuginfo": 2,
+                    "debuginfo": "2",
                     "incremental": false,
                     "lto": "false",
                     "name": "dev",
@@ -155,7 +155,7 @@ fn simple() {
                     "codegen_backend": null,
                     "codegen_units": null,
                     "debug_assertions": true,
-                    "debuginfo": 2,
+                    "debuginfo": "2",
                     "incremental": false,
                     "lto": "false",
                     "name": "dev",
@@ -198,7 +198,7 @@ fn simple() {
                     "codegen_backend": null,
                     "codegen_units": null,
                     "debug_assertions": true,
-                    "debuginfo": 2,
+                    "debuginfo": "2",
                     "incremental": false,
                     "lto": "false",
                     "name": "dev",