Improved collapse_debuginfo attribute, added command-line flag (no|external|yes)

Author: azhogin

compiler/rustc_expand/messages.ftl

@@ -16,6 +16,9 @@ expand_attributes_wrong_form =
 expand_cannot_be_name_of_macro =
     `{$trait_ident}` cannot be a name of {$macro_type} macro
 
+expand_collapse_debuginfo_illegal =
+    illegal value {$sym} for attribute #[collapse_debuginfo(no|external|yes)]
+
 expand_count_repetition_misplaced =
     `count` can not be placed inside the inner-most repetition
 

compiler/rustc_expand/src/base.rs

@@ -23,7 +23,7 @@ use rustc_session::errors::report_lit_error;
 use rustc_session::{parse::ParseSess, Limit, Session};
 use rustc_span::def_id::{CrateNum, DefId, LocalDefId};
 use rustc_span::edition::Edition;
-use rustc_span::hygiene::{AstPass, ExpnData, ExpnKind, LocalExpnId};
+use rustc_span::hygiene::{AstPass, CollapseDebuginfo, ExpnData, ExpnKind, LocalExpnId};
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{BytePos, FileName, Span, DUMMY_SP};
@@ -727,7 +727,7 @@ pub struct SyntaxExtension {
     pub local_inner_macros: bool,
     /// Should debuginfo for the macro be collapsed to the outermost expansion site (in other
     /// words, was the macro definition annotated with `#[collapse_debuginfo]`)?
-    pub collapse_debuginfo: bool,
+    pub collapse_debuginfo: CollapseDebuginfo,
 }
 
 impl SyntaxExtension {
@@ -757,7 +757,26 @@ impl SyntaxExtension {
             kind,
             allow_internal_unsafe: false,
             local_inner_macros: false,
-            collapse_debuginfo: false,
+            collapse_debuginfo: CollapseDebuginfo::Unspecified,
+        }
+    }
+
+    fn collapse_debuginfo_by_name(sess: &Session, attr: &Attribute) -> CollapseDebuginfo {
+        if let Some(value) = attr.value_str() {
+            match value {
+                sym::no => CollapseDebuginfo::No,
+                sym::external => CollapseDebuginfo::External,
+                sym::yes => CollapseDebuginfo::Yes,
+                _ => {
+                    sess.dcx()
+                        .emit_err(errors::CollapseDebuginfoIllegal { span: attr.span, sym: value });
+                    CollapseDebuginfo::Unspecified
+                }
+            }
+        } else {
+            // #[collapse_debuginfo] without enum value (#[collapse_debuginfo(no/external/yes)])
+            // considered as `yes`
+            CollapseDebuginfo::Yes
         }
     }
 
@@ -780,7 +799,9 @@ impl SyntaxExtension {
         let local_inner_macros = attr::find_by_name(attrs, sym::macro_export)
             .and_then(|macro_export| macro_export.meta_item_list())
             .is_some_and(|l| attr::list_contains_name(&l, sym::local_inner_macros));
-        let collapse_debuginfo = attr::contains_name(attrs, sym::collapse_debuginfo);
+        let collapse_debuginfo = attr::find_by_name(attrs, sym::collapse_debuginfo)
+            .and_then(|v| Some(Self::collapse_debuginfo_by_name(sess, v)))
+            .unwrap_or(CollapseDebuginfo::Unspecified);
         tracing::debug!(?local_inner_macros, ?collapse_debuginfo, ?allow_internal_unsafe);
 
         let (builtin_name, helper_attrs) = attr::find_by_name(attrs, sym::rustc_builtin_macro)

compiler/rustc_expand/src/errors.rs

@@ -58,6 +58,14 @@ pub(crate) struct ResolveRelativePath {
     pub path: String,
 }
 
+#[derive(Diagnostic)]
+#[diag(expand_collapse_debuginfo_illegal)]
+pub(crate) struct CollapseDebuginfoIllegal {
+    #[primary_span]
+    pub span: Span,
+    pub sym: Symbol,
+}
+
 #[derive(Diagnostic)]
 #[diag(expand_macro_const_stability)]
 pub(crate) struct MacroConstStability {

compiler/rustc_feature/src/builtin_attrs.rs

@@ -469,7 +469,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
 
     // `#[collapse_debuginfo]`
     gated!(
-        collapse_debuginfo, Normal, template!(Word), WarnFollowing,
+        collapse_debuginfo, Normal, template!(NameValueStr: "no|external|yes|..."), WarnFollowing,
         experimental!(collapse_debuginfo)
     ),
 

compiler/rustc_interface/src/tests.rs

@@ -742,6 +742,7 @@ fn test_unstable_options_tracking_hash() {
         })
     );
     tracked!(codegen_backend, Some("abc".to_string()));
+    tracked!(collapse_debuginfo, CollapseDebuginfo::Yes);
     tracked!(crate_attr, vec!["abc".to_string()]);
     tracked!(cross_crate_inline_threshold, InliningThreshold::Always);
     tracked!(debug_info_for_profiling, true);

compiler/rustc_middle/src/ty/mod.rs

@@ -49,7 +49,7 @@ use rustc_query_system::ich::StableHashingContext;
 use rustc_serialize::{Decodable, Encodable};
 use rustc_session::lint::LintBuffer;
 pub use rustc_session::lint::RegisteredTools;
-use rustc_span::hygiene::MacroKind;
+use rustc_span::hygiene::{CollapseDebuginfo, MacroKind};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{hygiene, ExpnId, ExpnKind, Span};
 use rustc_target::abi::{Align, FieldIdx, Integer, IntegerType, VariantIdx};
@@ -2531,8 +2531,18 @@ impl<'tcx> TyCtxt<'tcx> {
         if self.sess.opts.unstable_opts.debug_macros || !span.from_expansion() {
             return span;
         }
-        let collapse_debuginfo_enabled = self.features().collapse_debuginfo;
-        hygiene::walk_chain_collapsed(span, upto, collapse_debuginfo_enabled)
+        let collapse_debuginfo_flag = match self.sess.opts.unstable_opts.collapse_debuginfo {
+            rustc_session::config::CollapseDebuginfo::Unspecified => CollapseDebuginfo::Unspecified,
+            rustc_session::config::CollapseDebuginfo::No => CollapseDebuginfo::No,
+            rustc_session::config::CollapseDebuginfo::External => CollapseDebuginfo::External,
+            rustc_session::config::CollapseDebuginfo::Yes => CollapseDebuginfo::Yes,
+        };
+        hygiene::walk_chain_collapsed(
+            span,
+            upto,
+            self.features().collapse_debuginfo,
+            collapse_debuginfo_flag,
+        )
     }
 
     #[inline]

compiler/rustc_session/src/config.rs

@@ -3202,12 +3202,12 @@ pub enum WasiExecModel {
 /// how the hash should be calculated when adding a new command-line argument.
 pub(crate) mod dep_tracking {
     use super::{
-        BranchProtection, CFGuard, CFProtection, CrateType, DebugInfo, DebugInfoCompression,
-        ErrorOutputType, FunctionReturn, InliningThreshold, InstrumentCoverage, InstrumentXRay,
-        LinkerPluginLto, LocationDetail, LtoCli, NextSolverConfig, OomStrategy, OptLevel,
-        OutFileName, OutputType, OutputTypes, Polonius, RemapPathScopeComponents, ResolveDocLinks,
-        SourceFileHashAlgorithm, SplitDwarfKind, SwitchWithOptPath, SymbolManglingVersion,
-        TrimmedDefPaths, WasiExecModel,
+        BranchProtection, CFGuard, CFProtection, CollapseDebuginfo, CrateType, DebugInfo,
+        DebugInfoCompression, ErrorOutputType, FunctionReturn, InliningThreshold,
+        InstrumentCoverage, InstrumentXRay, LinkerPluginLto, LocationDetail, LtoCli,
+        NextSolverConfig, OomStrategy, OptLevel, OutFileName, OutputType, OutputTypes, Polonius,
+        RemapPathScopeComponents, ResolveDocLinks, SourceFileHashAlgorithm, SplitDwarfKind,
+        SwitchWithOptPath, SymbolManglingVersion, TrimmedDefPaths, WasiExecModel,
     };
     use crate::lint;
     use crate::utils::NativeLib;
@@ -3286,6 +3286,7 @@ pub(crate) mod dep_tracking {
         LtoCli,
         DebugInfo,
         DebugInfoCompression,
+        CollapseDebuginfo,
         UnstableFeatures,
         NativeLib,
         SanitizerSet,
@@ -3450,6 +3451,25 @@ pub enum ProcMacroExecutionStrategy {
     CrossThread,
 }
 
+/// How to perform collapse macros debug info
+/// if-ext - if macro from different crate (related to callsite code)
+/// | cmd \ attr    | no  | (unspecified) | external | yes |
+/// | no            | no  | no            | no       | no  |
+/// | (unspecified) | no  | no            | if-ext   | yes |
+/// | external      | no  | if-ext        | if-ext   | yes |
+/// | yes           | yes | yes           | yes      | yes |
+#[derive(Clone, Copy, PartialEq, Hash, Debug)]
+pub enum CollapseDebuginfo {
+    /// Unspecified value
+    Unspecified = 0,
+    /// Don't collapse debuginfo for the macro
+    No = 1,
+    /// Collapse debuginfo if command line flag enables collapsing
+    External = 2,
+    /// Collapse debuginfo for the macro
+    Yes = 3,
+}
+
 /// Which format to use for `-Z dump-mono-stats`
 #[derive(Clone, Copy, PartialEq, Hash, Debug)]
 pub enum DumpMonoStatsFormat {

compiler/rustc_session/src/options.rs

@@ -388,6 +388,7 @@ mod desc {
     pub const parse_cfprotection: &str = "`none`|`no`|`n` (default), `branch`, `return`, or `full`|`yes`|`y` (equivalent to `branch` and `return`)";
     pub const parse_debuginfo: &str = "either an integer (0, 1, 2), `none`, `line-directives-only`, `line-tables-only`, `limited`, or `full`";
     pub const parse_debuginfo_compression: &str = "one of `none`, `zlib`, or `zstd`";
+    pub const parse_collapse_debuginfo: &str = "one of `no`, `external`, or `yes`";
     pub const parse_strip: &str = "either `none`, `debuginfo`, or `symbols`";
     pub const parse_linker_flavor: &str = ::rustc_target::spec::LinkerFlavorCli::one_of();
     pub const parse_optimization_fuel: &str = "crate=integer";
@@ -1302,6 +1303,16 @@ mod parse {
         true
     }
 
+    pub(crate) fn parse_collapse_debuginfo(slot: &mut CollapseDebuginfo, v: Option<&str>) -> bool {
+        *slot = match v {
+            Some("no") => CollapseDebuginfo::No,
+            Some("external") => CollapseDebuginfo::External,
+            Some("yes") => CollapseDebuginfo::Yes,
+            _ => return false,
+        };
+        true
+    }
+
     pub(crate) fn parse_proc_macro_execution_strategy(
         slot: &mut ProcMacroExecutionStrategy,
         v: Option<&str>,
@@ -1534,6 +1545,8 @@ options! {
         "instrument control-flow architecture protection"),
     codegen_backend: Option<String> = (None, parse_opt_string, [TRACKED],
         "the backend to use"),
+    collapse_debuginfo: CollapseDebuginfo = (CollapseDebuginfo::Unspecified, parse_collapse_debuginfo, [TRACKED],
+        "set option for collapse macros debug info"),
     combine_cgu: bool = (false, parse_bool, [TRACKED],
         "combine CGUs into a single one"),
     crate_attr: Vec<String> = (Vec::new(), parse_string_push, [TRACKED],

compiler/rustc_span/src/hygiene.rs

@@ -163,6 +163,41 @@ pub enum Transparency {
     Opaque,
 }
 
+/// How to perform collapse macros debug info
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Hash, Debug, Encodable, Decodable)]
+#[derive(HashStable_Generic)]
+pub enum CollapseDebuginfo {
+    /// Unspecified value
+    Unspecified = 0,
+    /// Don't collapse debuginfo for the macro
+    No = 1,
+    /// Collapse debuginfo if command line flag enables collapsing
+    External = 2,
+    /// Collapse debuginfo for the macro
+    Yes = 3,
+}
+
+/// if-ext - if macro from different crate (related to callsite code)
+/// | cmd \ attr    | no  | (unspecified) | external | yes |
+/// | no            | no  | no            | no       | no  |
+/// | (unspecified) | no  | no            | if-ext   | yes |
+/// | external      | no  | if-ext        | if-ext   | yes |
+/// | yes           | yes | yes           | yes      | yes |
+impl CollapseDebuginfo {
+    pub fn should_collapse(self, flag: CollapseDebuginfo, ext: bool) -> bool {
+        const NO: bool = false;
+        const YES: bool = true;
+        #[rustfmt::skip]
+        let collapse_table = [
+            [NO,  NO,  NO,  NO ],
+            [NO,  NO,  ext, YES],
+            [NO,  ext, ext, YES],
+            [YES, YES, YES, YES],
+        ];
+        collapse_table[flag as usize][self as usize]
+    }
+}
+
 impl LocalExpnId {
     /// The ID of the theoretical expansion that generates freshly parsed, unexpanded AST.
     pub const ROOT: LocalExpnId = LocalExpnId::from_u32(0);
@@ -464,7 +499,8 @@ impl HygieneData {
         &self,
         mut span: Span,
         to: Span,
-        collapse_debuginfo_enabled: bool,
+        collapse_debuginfo_feature_enabled: bool,
+        collapse_debuginfo_flag: CollapseDebuginfo,
     ) -> Span {
         let orig_span = span;
         let mut ret_span = span;
@@ -477,7 +513,10 @@ impl HygieneData {
             let expn_data = self.expn_data(outer_expn);
             debug!("walk_chain_collapsed({:?}): expn_data={:?}", span, expn_data);
             span = expn_data.call_site;
-            if !collapse_debuginfo_enabled || expn_data.collapse_debuginfo {
+            let is_ext = !expn_data.macro_def_id.map_or(false, |v| v.is_local());
+            if !collapse_debuginfo_feature_enabled
+                || expn_data.collapse_debuginfo.should_collapse(collapse_debuginfo_flag, is_ext)
+            {
                 ret_span = span;
             }
         }
@@ -601,8 +640,20 @@ pub fn walk_chain(span: Span, to: SyntaxContext) -> Span {
     HygieneData::with(|data| data.walk_chain(span, to))
 }
 
-pub fn walk_chain_collapsed(span: Span, to: Span, collapse_debuginfo_enabled: bool) -> Span {
-    HygieneData::with(|hdata| hdata.walk_chain_collapsed(span, to, collapse_debuginfo_enabled))
+pub fn walk_chain_collapsed(
+    span: Span,
+    to: Span,
+    collapse_debuginfo_feature_enabled: bool,
+    collapse_debuginfo_flag: CollapseDebuginfo,
+) -> Span {
+    HygieneData::with(|hdata| {
+        hdata.walk_chain_collapsed(
+            span,
+            to,
+            collapse_debuginfo_feature_enabled,
+            collapse_debuginfo_flag,
+        )
+    })
 }
 
 pub fn update_dollar_crate_names(mut get_name: impl FnMut(SyntaxContext) -> Symbol) {
@@ -957,7 +1008,7 @@ pub struct ExpnData {
     pub local_inner_macros: bool,
     /// Should debuginfo for the macro be collapsed to the outermost expansion site (in other
     /// words, was the macro definition annotated with `#[collapse_debuginfo]`)?
-    pub(crate) collapse_debuginfo: bool,
+    pub(crate) collapse_debuginfo: CollapseDebuginfo,
 }
 
 impl !PartialEq for ExpnData {}
@@ -975,7 +1026,7 @@ impl ExpnData {
         parent_module: Option<DefId>,
         allow_internal_unsafe: bool,
         local_inner_macros: bool,
-        collapse_debuginfo: bool,
+        collapse_debuginfo: CollapseDebuginfo,
     ) -> ExpnData {
         ExpnData {
             kind,
@@ -1013,7 +1064,7 @@ impl ExpnData {
             disambiguator: 0,
             allow_internal_unsafe: false,
             local_inner_macros: false,
-            collapse_debuginfo: false,
+            collapse_debuginfo: CollapseDebuginfo::Unspecified,
         }
     }
 

compiler/rustc_span/src/symbol.rs

@@ -748,6 +748,7 @@ symbols! {
         extern_in_paths,
         extern_prelude,
         extern_types,
+        external,
         external_doc,
         f,
         f16c_target_feature,
@@ -1810,6 +1811,7 @@ symbols! {
         xmm_reg,
         yeet_desugar_details,
         yeet_expr,
+        yes,
         yield_expr,
         ymm_reg,
         zmm_reg,