Auto merge of #111641 - michaelwoerister:debugger-visualizer-fixes, r=cjgillot

Fix dependency tracking for debugger visualizers

This PR fixes dependency tracking for debugger visualizer files by changing the `debugger_visualizers` query to an `eval_always` query that scans the AST while it is still available. This way the set of visualizer files is already available when dep-info is emitted. Since the query is turned into an `eval_always` query, dependency tracking will now reliably detect changes to the visualizer script files themselves.

TODO:
 - [x] perf.rlo
 - [x] Needs a bit more documentation in some places
 - [x] Needs regression test for the incr. comp. case

Fixes https://github.com/rust-lang/rust/issues/111226
Fixes https://github.com/rust-lang/rust/issues/111227
Fixes https://github.com/rust-lang/rust/issues/111295

r? `@wesleywiser`
cc `@gibbyfree`

compiler/rustc_middle/src/hir/map/mod.rs

@@ -1,4 +1,5 @@
 use crate::hir::{ModuleItems, Owner};
+use crate::middle::debugger_visualizer::DebuggerVisualizerFile;
 use crate::query::LocalCrate;
 use crate::ty::TyCtxt;
 use rustc_ast as ast;
@@ -1165,11 +1166,26 @@ pub(super) fn crate_hash(tcx: TyCtxt<'_>, _: LocalCrate) -> Svh {
 
     source_file_names.sort_unstable();
 
+    // We have to take care of debugger visualizers explicitly. The HIR (and
+    // thus `hir_body_hash`) contains the #[debugger_visualizer] attributes but
+    // these attributes only store the file path to the visualizer file, not
+    // their content. Yet that content is exported into crate metadata, so any
+    // changes to it need to be reflected in the crate hash.
+    let debugger_visualizers: Vec<_> = tcx
+        .debugger_visualizers(LOCAL_CRATE)
+        .iter()
+        // We ignore the path to the visualizer file since it's not going to be
+        // encoded in crate metadata and we already hash the full contents of
+        // the file.
+        .map(DebuggerVisualizerFile::path_erased)
+        .collect();
+
     let crate_hash: Fingerprint = tcx.with_stable_hashing_context(|mut hcx| {
         let mut stable_hasher = StableHasher::new();
         hir_body_hash.hash_stable(&mut hcx, &mut stable_hasher);
         upstream_crates.hash_stable(&mut hcx, &mut stable_hasher);
         source_file_names.hash_stable(&mut hcx, &mut stable_hasher);
+        debugger_visualizers.hash_stable(&mut hcx, &mut stable_hasher);
         if tcx.sess.opts.incremental_relative_spans() {
             let definitions = tcx.definitions_untracked();
             let mut owner_spans: Vec<_> = krate

compiler/rustc_middle/src/middle/debugger_visualizer.rs

@@ -0,0 +1,38 @@
+use rustc_data_structures::sync::Lrc;
+use std::path::PathBuf;
+
+#[derive(HashStable)]
+#[derive(Copy, PartialEq, PartialOrd, Clone, Ord, Eq, Hash, Debug, Encodable, Decodable)]
+pub enum DebuggerVisualizerType {
+    Natvis,
+    GdbPrettyPrinter,
+}
+
+/// A single debugger visualizer file.
+#[derive(HashStable)]
+#[derive(Clone, Debug, Hash, PartialEq, Eq, PartialOrd, Ord, Encodable, Decodable)]
+pub struct DebuggerVisualizerFile {
+    /// The complete debugger visualizer source.
+    pub src: Lrc<[u8]>,
+    /// Indicates which visualizer type this targets.
+    pub visualizer_type: DebuggerVisualizerType,
+    /// The file path to the visualizer file. This is used for reporting
+    /// visualizer files in dep-info. Before it is written to crate metadata,
+    /// the path is erased to `None`, so as not to emit potentially privacy
+    /// sensitive data.
+    pub path: Option<PathBuf>,
+}
+
+impl DebuggerVisualizerFile {
+    pub fn new(src: Lrc<[u8]>, visualizer_type: DebuggerVisualizerType, path: PathBuf) -> Self {
+        DebuggerVisualizerFile { src, visualizer_type, path: Some(path) }
+    }
+
+    pub fn path_erased(&self) -> Self {
+        DebuggerVisualizerFile {
+            src: self.src.clone(),
+            visualizer_type: self.visualizer_type,
+            path: None,
+        }
+    }
+}

compiler/rustc_middle/src/middle/mod.rs

@@ -1,4 +1,5 @@
 pub mod codegen_fn_attrs;
+pub mod debugger_visualizer;
 pub mod dependency_format;
 pub mod exported_symbols;
 pub mod lang_items;

compiler/rustc_middle/src/query/mod.rs

@@ -12,6 +12,7 @@ use crate::infer::canonical::{self, Canonical};
 use crate::lint::LintExpectation;
 use crate::metadata::ModChild;
 use crate::middle::codegen_fn_attrs::CodegenFnAttrs;
+use crate::middle::debugger_visualizer::DebuggerVisualizerFile;
 use crate::middle::exported_symbols::{ExportedSymbol, SymbolExportInfo};
 use crate::middle::lib_features::LibFeatures;
 use crate::middle::privacy::EffectiveVisibilities;
@@ -1784,12 +1785,18 @@ rustc_queries! {
         desc { "looking at the source for a crate" }
         separate_provide_extern
     }
+
     /// Returns the debugger visualizers defined for this crate.
-    query debugger_visualizers(_: CrateNum) -> &'tcx Vec<rustc_span::DebuggerVisualizerFile> {
+    /// NOTE: This query has to be marked `eval_always` because it reads data
+    ///       directly from disk that is not tracked anywhere else. I.e. it
+    ///       represents a genuine input to the query system.
+    query debugger_visualizers(_: CrateNum) -> &'tcx Vec<DebuggerVisualizerFile> {
         arena_cache
         desc { "looking up the debugger visualizers for this crate" }
         separate_provide_extern
+        eval_always
     }
+
     query postorder_cnums(_: ()) -> &'tcx [CrateNum] {
         eval_always
         desc { "generating a postorder list of CrateNums" }

compiler/rustc_middle/src/ty/parameterized.rs

@@ -56,6 +56,7 @@ trivially_parameterized_over_tcx! {
     std::string::String,
     crate::metadata::ModChild,
     crate::middle::codegen_fn_attrs::CodegenFnAttrs,
+    crate::middle::debugger_visualizer::DebuggerVisualizerFile,
     crate::middle::exported_symbols::SymbolExportInfo,
     crate::middle::resolve_bound_vars::ObjectLifetimeDefault,
     crate::mir::ConstQualifs,
@@ -91,7 +92,6 @@ trivially_parameterized_over_tcx! {
     rustc_session::cstore::ForeignModule,
     rustc_session::cstore::LinkagePreference,
     rustc_session::cstore::NativeLib,
-    rustc_span::DebuggerVisualizerFile,
     rustc_span::ExpnData,
     rustc_span::ExpnHash,
     rustc_span::ExpnId,