Auto merge of #93655 - matthiaskrgr:rollup-dm88b02, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #90132 (Stabilize `-Z instrument-coverage` as `-C instrument-coverage`)
 - #91589 (impl `Arc::unwrap_or_clone`)
 - #93495 (kmc-solid: Fix off-by-one error in `SystemTime::now`)
 - #93576 (Emit more valid HTML from rustdoc)
 - #93608 (Clean up `find_library_crate`)
 - #93612 (doc: use U+2212 for minus sign in integer MIN/MAX text)
 - #93615 (Fix `isize` optimization in `StableHasher` for big-endian architectures)

Failed merges:

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

compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs

@@ -39,7 +39,7 @@ pub fn finalize<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) {
     // LLVM 12.
     let version = coverageinfo::mapping_version();
     if version < 4 {
-        tcx.sess.fatal("rustc option `-Z instrument-coverage` requires LLVM 12 or higher.");
+        tcx.sess.fatal("rustc option `-C instrument-coverage` requires LLVM 12 or higher.");
     }
 
     debug!("Generating coverage map for CodegenUnit: `{}`", cx.codegen_unit.name());
@@ -274,7 +274,7 @@ fn save_function_record(
 /// (functions referenced by other "used" or public items). Any other functions considered unused,
 /// or "Unreachable", were still parsed and processed through the MIR stage, but were not
 /// codegenned. (Note that `-Clink-dead-code` can force some unused code to be codegenned, but
-/// that flag is known to cause other errors, when combined with `-Z instrument-coverage`; and
+/// that flag is known to cause other errors, when combined with `-C instrument-coverage`; and
 /// `-Clink-dead-code` will not generate code for unused generic functions.)
 ///
 /// We can find the unused functions (including generic functions) by the set difference of all MIR

compiler/rustc_codegen_ssa/src/traits/coverageinfo.rs

@@ -22,15 +22,15 @@ pub trait CoverageInfoMethods<'tcx>: BackendTypes {
 
 pub trait CoverageInfoBuilderMethods<'tcx>: BackendTypes {
     /// Returns true if the function source hash was added to the coverage map (even if it had
-    /// already been added, for this instance). Returns false *only* if `-Z instrument-coverage` is
+    /// already been added, for this instance). Returns false *only* if `-C instrument-coverage` is
     /// not enabled (a coverage map is not being generated).
     fn set_function_source_hash(
         &mut self,
         instance: Instance<'tcx>,
         function_source_hash: u64,
     ) -> bool;
 
-    /// Returns true if the counter was added to the coverage map; false if `-Z instrument-coverage`
+    /// Returns true if the counter was added to the coverage map; false if `-C instrument-coverage`
     /// is not enabled (a coverage map is not being generated).
     fn add_coverage_counter(
         &mut self,
@@ -40,7 +40,7 @@ pub trait CoverageInfoBuilderMethods<'tcx>: BackendTypes {
     ) -> bool;
 
     /// Returns true if the expression was added to the coverage map; false if
-    /// `-Z instrument-coverage` is not enabled (a coverage map is not being generated).
+    /// `-C instrument-coverage` is not enabled (a coverage map is not being generated).
     fn add_coverage_counter_expression(
         &mut self,
         instance: Instance<'tcx>,
@@ -51,7 +51,7 @@ pub trait CoverageInfoBuilderMethods<'tcx>: BackendTypes {
         region: Option<CodeRegion>,
     ) -> bool;
 
-    /// Returns true if the region was added to the coverage map; false if `-Z instrument-coverage`
+    /// Returns true if the region was added to the coverage map; false if `-C instrument-coverage`
     /// is not enabled (a coverage map is not being generated).
     fn add_coverage_unreachable(&mut self, instance: Instance<'tcx>, region: CodeRegion) -> bool;
 }

compiler/rustc_data_structures/src/stable_hasher.rs

@@ -133,18 +133,18 @@ impl Hasher for StableHasher {
 
     #[inline]
     fn write_isize(&mut self, i: isize) {
-        // Always treat isize as i64 so we get the same results on 32 and 64 bit
+        // Always treat isize as a 64-bit number so we get the same results on 32 and 64 bit
         // platforms. This is important for symbol hashes when cross compiling,
         // for example. Sign extending here is preferable as it means that the
         // same negative number hashes the same on both 32 and 64 bit platforms.
-        let value = (i as i64).to_le() as u64;
+        let value = i as u64;
 
         // Cold path
         #[cold]
         #[inline(never)]
         fn hash_value(state: &mut SipHasher128, value: u64) {
             state.write_u8(0xFF);
-            state.write_u64(value);
+            state.write_u64(value.to_le());
         }
 
         // `isize` values often seem to have a small (positive) numeric value in practice.
@@ -161,6 +161,10 @@ impl Hasher for StableHasher {
         // 8 bytes. Since this prefix cannot occur when we hash a single byte, when we hash two
         // `isize`s that fit within a different amount of bytes, they should always produce a different
         // byte stream for the hasher.
+        //
+        // To ensure that this optimization hashes the exact same bytes on both little-endian and
+        // big-endian architectures, we compare the value with 0xFF before we convert the number
+        // into a unified representation (little-endian).
         if value < 0xFF {
             self.state.write_u8(value as u8);
         } else {

compiler/rustc_data_structures/src/stable_hasher/tests.rs

@@ -159,4 +159,5 @@ fn test_isize_compression() {
     check_hash(0xAAAA, 0xAAAAAA);
     check_hash(0xAAAAAA, 0xAAAAAAAA);
     check_hash(0xFF, 0xFFFFFFFFFFFFFFFF);
+    check_hash(u64::MAX /* -1 */, 1);
 }

compiler/rustc_interface/src/tests.rs

@@ -575,6 +575,7 @@ fn test_codegen_options_tracking_hash() {
     tracked!(force_frame_pointers, Some(false));
     tracked!(force_unwind_tables, Some(true));
     tracked!(inline_threshold, Some(0xf007ba11));
+    tracked!(instrument_coverage, Some(InstrumentCoverage::All));
     tracked!(linker_plugin_lto, LinkerPluginLto::LinkerPluginAuto);
     tracked!(link_dead_code, Some(true));
     tracked!(llvm_args, vec![String::from("1"), String::from("2")]);

compiler/rustc_metadata/src/locator.rs

@@ -223,7 +223,7 @@ use rustc_data_structures::sync::MetadataRef;
 use rustc_errors::{struct_span_err, FatalError};
 use rustc_session::config::{self, CrateType};
 use rustc_session::cstore::{CrateSource, MetadataLoader};
-use rustc_session::filesearch::{FileDoesntMatch, FileMatches, FileSearch};
+use rustc_session::filesearch::FileSearch;
 use rustc_session::search_paths::PathKind;
 use rustc_session::utils::CanonicalizedPath;
 use rustc_session::Session;
@@ -371,15 +371,20 @@ impl<'a> CrateLocator<'a> {
         extra_prefix: &str,
         seen_paths: &mut FxHashSet<PathBuf>,
     ) -> Result<Option<Library>, CrateError> {
-        // want: crate_name.dir_part() + prefix + crate_name.file_part + "-"
-        let dylib_prefix = format!("{}{}{}", self.target.dll_prefix, self.crate_name, extra_prefix);
-        let rlib_prefix = format!("lib{}{}", self.crate_name, extra_prefix);
+        let rmeta_prefix = &format!("lib{}{}", self.crate_name, extra_prefix);
+        let rlib_prefix = rmeta_prefix;
+        let dylib_prefix =
+            &format!("{}{}{}", self.target.dll_prefix, self.crate_name, extra_prefix);
         let staticlib_prefix =
-            format!("{}{}{}", self.target.staticlib_prefix, self.crate_name, extra_prefix);
+            &format!("{}{}{}", self.target.staticlib_prefix, self.crate_name, extra_prefix);
+
+        let rmeta_suffix = ".rmeta";
+        let rlib_suffix = ".rlib";
+        let dylib_suffix = &self.target.dll_suffix;
+        let staticlib_suffix = &self.target.staticlib_suffix;
 
         let mut candidates: FxHashMap<_, (FxHashMap<_, _>, FxHashMap<_, _>, FxHashMap<_, _>)> =
             Default::default();
-        let mut staticlibs = vec![];
 
         // First, find all possible candidate rlibs and dylibs purely based on
         // the name of the files themselves. We're trying to match against an
@@ -394,46 +399,50 @@ impl<'a> CrateLocator<'a> {
         // of the crate id (path/name/id).
         //
         // The goal of this step is to look at as little metadata as possible.
-        self.filesearch.search(|spf, kind| {
-            let file = match &spf.file_name_str {
-                None => return FileDoesntMatch,
-                Some(file) => file,
-            };
-            let (hash, found_kind) = if file.starts_with(&rlib_prefix) && file.ends_with(".rlib") {
-                (&file[(rlib_prefix.len())..(file.len() - ".rlib".len())], CrateFlavor::Rlib)
-            } else if file.starts_with(&rlib_prefix) && file.ends_with(".rmeta") {
-                (&file[(rlib_prefix.len())..(file.len() - ".rmeta".len())], CrateFlavor::Rmeta)
-            } else if file.starts_with(&dylib_prefix) && file.ends_with(&self.target.dll_suffix) {
-                (
-                    &file[(dylib_prefix.len())..(file.len() - self.target.dll_suffix.len())],
-                    CrateFlavor::Dylib,
-                )
-            } else {
-                if file.starts_with(&staticlib_prefix)
-                    && file.ends_with(&self.target.staticlib_suffix)
-                {
-                    staticlibs
-                        .push(CrateMismatch { path: spf.path.clone(), got: "static".to_string() });
-                }
-                return FileDoesntMatch;
-            };
+        // Unfortunately, the prefix-based matching sometimes is over-eager.
+        // E.g. if `rlib_suffix` is `libstd` it'll match the file
+        // `libstd_detect-8d6701fb958915ad.rlib` (incorrect) as well as
+        // `libstd-f3ab5b1dea981f17.rlib` (correct). But this is hard to avoid
+        // given that `extra_filename` comes from the `-C extra-filename`
+        // option and thus can be anything, and the incorrect match will be
+        // handled safely in `extract_one`.
+        for search_path in self.filesearch.search_paths() {
+            debug!("searching {}", search_path.dir.display());
+            for spf in search_path.files.iter() {
+                debug!("testing {}", spf.path.display());
+
+                let f = &spf.file_name_str;
+                let (hash, kind) = if f.starts_with(rlib_prefix) && f.ends_with(rlib_suffix) {
+                    (&f[rlib_prefix.len()..(f.len() - rlib_suffix.len())], CrateFlavor::Rlib)
+                } else if f.starts_with(rmeta_prefix) && f.ends_with(rmeta_suffix) {
+                    (&f[rmeta_prefix.len()..(f.len() - rmeta_suffix.len())], CrateFlavor::Rmeta)
+                } else if f.starts_with(dylib_prefix) && f.ends_with(dylib_suffix) {
+                    (&f[dylib_prefix.len()..(f.len() - dylib_suffix.len())], CrateFlavor::Dylib)
+                } else {
+                    if f.starts_with(staticlib_prefix) && f.ends_with(staticlib_suffix) {
+                        self.crate_rejections.via_kind.push(CrateMismatch {
+                            path: spf.path.clone(),
+                            got: "static".to_string(),
+                        });
+                    }
+                    continue;
+                };
 
-            info!("lib candidate: {}", spf.path.display());
+                info!("lib candidate: {}", spf.path.display());
 
-            let (rlibs, rmetas, dylibs) = candidates.entry(hash.to_string()).or_default();
-            let path = fs::canonicalize(&spf.path).unwrap_or_else(|_| spf.path.clone());
-            if seen_paths.contains(&path) {
-                return FileDoesntMatch;
-            };
-            seen_paths.insert(path.clone());
-            match found_kind {
-                CrateFlavor::Rlib => rlibs.insert(path, kind),
-                CrateFlavor::Rmeta => rmetas.insert(path, kind),
-                CrateFlavor::Dylib => dylibs.insert(path, kind),
-            };
-            FileMatches
-        });
-        self.crate_rejections.via_kind.extend(staticlibs);
+                let (rlibs, rmetas, dylibs) = candidates.entry(hash.to_string()).or_default();
+                let path = fs::canonicalize(&spf.path).unwrap_or_else(|_| spf.path.clone());
+                if seen_paths.contains(&path) {
+                    continue;
+                };
+                seen_paths.insert(path.clone());
+                match kind {
+                    CrateFlavor::Rlib => rlibs.insert(path, search_path.kind),
+                    CrateFlavor::Rmeta => rmetas.insert(path, search_path.kind),
+                    CrateFlavor::Dylib => dylibs.insert(path, search_path.kind),
+                };
+            }
+        }
 
         // We have now collected all known libraries into a set of candidates
         // keyed of the filename hash listed. For each filename, we also have a

compiler/rustc_middle/src/mir/mod.rs

@@ -1577,7 +1577,7 @@ pub enum StatementKind<'tcx> {
     /// - `Bivariant` -- no effect
     AscribeUserType(Box<(Place<'tcx>, UserTypeProjection)>, ty::Variance),
 
-    /// Marks the start of a "coverage region", injected with '-Zinstrument-coverage'. A
+    /// Marks the start of a "coverage region", injected with '-Cinstrument-coverage'. A
     /// `Coverage` statement carries metadata about the coverage region, used to inject a coverage
     /// map into the binary. If `Coverage::kind` is a `Counter`, the statement also generates
     /// executable code, to increment a counter variable at runtime, each time the code region is

compiler/rustc_middle/src/mir/query.rs

@@ -390,7 +390,7 @@ pub struct DestructuredConst<'tcx> {
 }
 
 /// Coverage information summarized from a MIR if instrumented for source code coverage (see
-/// compiler option `-Zinstrument-coverage`). This information is generated by the
+/// compiler option `-Cinstrument-coverage`). This information is generated by the
 /// `InstrumentCoverage` MIR pass and can be retrieved via the `coverageinfo` query.
 #[derive(Clone, TyEncodable, TyDecodable, Debug, HashStable)]
 pub struct CoverageInfo {

compiler/rustc_middle/src/query/mod.rs

@@ -384,7 +384,7 @@ rustc_queries! {
     }
 
     /// Returns coverage summary info for a function, after executing the `InstrumentCoverage`
-    /// MIR pass (assuming the -Zinstrument-coverage option is enabled).
+    /// MIR pass (assuming the -Cinstrument-coverage option is enabled).
     query coverageinfo(key: ty::InstanceDef<'tcx>) -> mir::CoverageInfo {
         desc { |tcx| "retrieving coverage info from MIR for `{}`", tcx.def_path_str(key.def_id()) }
         storage(ArenaCacheSelector<'tcx>)

compiler/rustc_mir_transform/src/coverage/debug.rs

@@ -3,7 +3,7 @@
 //!
 //! To enable coverage, include the rustc command line option:
 //!
-//!   * `-Z instrument-coverage`
+//!   * `-C instrument-coverage`
 //!
 //! MIR Dump Files, with additional `CoverageGraph` graphviz and `CoverageSpan` spanview
 //! ------------------------------------------------------------------------------------

compiler/rustc_mir_transform/src/simplify.rs

@@ -303,7 +303,7 @@ pub fn remove_dead_blocks<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
 /// evaluation: `if false { ... }`.
 ///
 /// Those statements are bypassed by redirecting paths in the CFG around the
-/// `dead blocks`; but with `-Z instrument-coverage`, the dead blocks usually
+/// `dead blocks`; but with `-C instrument-coverage`, the dead blocks usually
 /// include `Coverage` statements representing the Rust source code regions to
 /// be counted at runtime. Without these `Coverage` statements, the regions are
 /// lost, and the Rust source code will show no coverage information.

compiler/rustc_session/src/config.rs

@@ -127,16 +127,16 @@ pub enum MirSpanview {
     Block,
 }
 
-/// The different settings that the `-Z instrument-coverage` flag can have.
+/// The different settings that the `-C instrument-coverage` flag can have.
 ///
-/// Coverage instrumentation now supports combining `-Z instrument-coverage`
+/// Coverage instrumentation now supports combining `-C instrument-coverage`
 /// with compiler and linker optimization (enabled with `-O` or `-C opt-level=1`
 /// and higher). Nevertheless, there are many variables, depending on options
 /// selected, code structure, and enabled attributes. If errors are encountered,
 /// either while compiling or when generating `llvm-cov show` reports, consider
 /// lowering the optimization level, including or excluding `-C link-dead-code`,
-/// or using `-Z instrument-coverage=except-unused-functions` or `-Z
-/// instrument-coverage=except-unused-generics`.
+/// or using `-Zunstable-options -C instrument-coverage=except-unused-functions`
+/// or `-Zunstable-options -C instrument-coverage=except-unused-generics`.
 ///
 /// Note that `ExceptUnusedFunctions` means: When `mapgen.rs` generates the
 /// coverage map, it will not attempt to generate synthetic functions for unused
@@ -148,13 +148,13 @@ pub enum MirSpanview {
 /// unless the function has type parameters.
 #[derive(Clone, Copy, PartialEq, Hash, Debug)]
 pub enum InstrumentCoverage {
-    /// Default `-Z instrument-coverage` or `-Z instrument-coverage=statement`
+    /// Default `-C instrument-coverage` or `-C instrument-coverage=statement`
     All,
-    /// `-Z instrument-coverage=except-unused-generics`
+    /// `-Zunstable-options -C instrument-coverage=except-unused-generics`
     ExceptUnusedGenerics,
-    /// `-Z instrument-coverage=except-unused-functions`
+    /// `-Zunstable-options -C instrument-coverage=except-unused-functions`
     ExceptUnusedFunctions,
-    /// `-Z instrument-coverage=off` (or `no`, etc.)
+    /// `-C instrument-coverage=off` (or `no`, etc.)
     Off,
 }
 
@@ -2195,18 +2195,44 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         _ => {}
     }
 
-    if debugging_opts.instrument_coverage.is_some()
-        && debugging_opts.instrument_coverage != Some(InstrumentCoverage::Off)
-    {
+    // Handle both `-Z instrument-coverage` and `-C instrument-coverage`; the latter takes
+    // precedence.
+    match (cg.instrument_coverage, debugging_opts.instrument_coverage) {
+        (Some(ic_c), Some(ic_z)) if ic_c != ic_z => {
+            early_error(
+                error_format,
+                "incompatible values passed for `-C instrument-coverage` \
+                and `-Z instrument-coverage`",
+            );
+        }
+        (Some(InstrumentCoverage::Off | InstrumentCoverage::All), _) => {}
+        (Some(_), _) if !debugging_opts.unstable_options => {
+            early_error(
+                error_format,
+                "`-C instrument-coverage=except-*` requires `-Z unstable-options`",
+            );
+        }
+        (None, None) => {}
+        (None, ic) => {
+            early_warn(
+                error_format,
+                "`-Z instrument-coverage` is deprecated; use `-C instrument-coverage`",
+            );
+            cg.instrument_coverage = ic;
+        }
+        _ => {}
+    }
+
+    if cg.instrument_coverage.is_some() && cg.instrument_coverage != Some(InstrumentCoverage::Off) {
         if cg.profile_generate.enabled() || cg.profile_use.is_some() {
             early_error(
                 error_format,
-                "option `-Z instrument-coverage` is not compatible with either `-C profile-use` \
+                "option `-C instrument-coverage` is not compatible with either `-C profile-use` \
                 or `-C profile-generate`",
             );
         }
 
-        // `-Z instrument-coverage` implies `-C symbol-mangling-version=v0` - to ensure consistent
+        // `-C instrument-coverage` implies `-C symbol-mangling-version=v0` - to ensure consistent
         // and reversible name mangling. Note, LLVM coverage tools can analyze coverage over
         // multiple runs, including some changes to source code; so mangled names must be consistent
         // across compilations.
@@ -2215,7 +2241,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
             Some(SymbolManglingVersion::Legacy) => {
                 early_warn(
                     error_format,
-                    "-Z instrument-coverage requires symbol mangling version `v0`, \
+                    "-C instrument-coverage requires symbol mangling version `v0`, \
                     but `-C symbol-mangling-version=legacy` was specified",
                 );
             }