Auto merge of #147175 - Zalathar:rollup-kzpdwu3, r=Zalathar

Rollup of 4 pull requests

Successful merges:

 - #146518 (Improve the documentation around `ZERO_AR_DATE`)
 - #146596 (Add a dummy codegen backend)
 - #146617 (Don’t suggest foreign `doc(hidden)` types in "the following other types implement trait" diagnostics)
 - #146635 (cg_llvm: Stop using `as_c_char_ptr` for coverage-related bindings)

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

Author: bors

compiler/rustc_codegen_llvm/src/coverageinfo/llvm_cov.rs

@@ -2,26 +2,25 @@
 
 use std::ffi::CString;
 
-use crate::common::AsCCharPtr;
 use crate::coverageinfo::ffi;
 use crate::llvm;
 
 pub(crate) fn covmap_var_name() -> CString {
-    CString::new(llvm::build_byte_buffer(|s| unsafe {
+    CString::new(llvm::build_byte_buffer(|s| {
         llvm::LLVMRustCoverageWriteCovmapVarNameToString(s);
     }))
     .expect("covmap variable name should not contain NUL")
 }
 
 pub(crate) fn covmap_section_name(llmod: &llvm::Module) -> CString {
-    CString::new(llvm::build_byte_buffer(|s| unsafe {
+    CString::new(llvm::build_byte_buffer(|s| {
         llvm::LLVMRustCoverageWriteCovmapSectionNameToString(llmod, s);
     }))
     .expect("covmap section name should not contain NUL")
 }
 
 pub(crate) fn covfun_section_name(llmod: &llvm::Module) -> CString {
-    CString::new(llvm::build_byte_buffer(|s| unsafe {
+    CString::new(llvm::build_byte_buffer(|s| {
         llvm::LLVMRustCoverageWriteCovfunSectionNameToString(llmod, s);
     }))
     .expect("covfun section name should not contain NUL")
@@ -34,7 +33,7 @@ pub(crate) fn create_pgo_func_name_var<'ll>(
     unsafe {
         llvm::LLVMRustCoverageCreatePGOFuncNameVar(
             llfn,
-            mangled_fn_name.as_c_char_ptr(),
+            mangled_fn_name.as_ptr(),
             mangled_fn_name.len(),
         )
     }
@@ -44,7 +43,7 @@ pub(crate) fn write_filenames_to_buffer(filenames: &[impl AsRef<str>]) -> Vec<u8
     let (pointers, lengths) = filenames
         .into_iter()
         .map(AsRef::as_ref)
-        .map(|s: &str| (s.as_c_char_ptr(), s.len()))
+        .map(|s: &str| (s.as_ptr(), s.len()))
         .unzip::<_, _, Vec<_>, Vec<_>>();
 
     llvm::build_byte_buffer(|buffer| unsafe {
@@ -89,12 +88,12 @@ pub(crate) fn write_function_mappings_to_buffer(
 /// Hashes some bytes into a 64-bit hash, via LLVM's `IndexedInstrProf::ComputeHash`,
 /// as required for parts of the LLVM coverage mapping format.
 pub(crate) fn hash_bytes(bytes: &[u8]) -> u64 {
-    unsafe { llvm::LLVMRustCoverageHashBytes(bytes.as_c_char_ptr(), bytes.len()) }
+    unsafe { llvm::LLVMRustCoverageHashBytes(bytes.as_ptr(), bytes.len()) }
 }
 
 /// Returns LLVM's `coverage::CovMapVersion::CurrentVersion` (CoverageMapping.h)
 /// as a raw numeric value. For historical reasons, the numeric value is 1 less
 /// than the number in the version's name, so `Version7` is actually `6u32`.
 pub(crate) fn mapping_version() -> u32 {
-    unsafe { llvm::LLVMRustCoverageMappingVersion() }
+    llvm::LLVMRustCoverageMappingVersion()
 }

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -2256,8 +2256,11 @@ unsafe extern "C" {
         ConstraintsLen: size_t,
     ) -> bool;
 
+    /// A list of pointer-length strings is passed as two pointer-length slices,
+    /// one slice containing pointers and one slice containing their corresponding
+    /// lengths. The implementation will check that both slices have the same length.
     pub(crate) fn LLVMRustCoverageWriteFilenamesToBuffer(
-        Filenames: *const *const c_char,
+        Filenames: *const *const c_uchar, // See "PTR_LEN_STR".
         FilenamesLen: size_t,
         Lengths: *const size_t,
         LengthsLen: size_t,
@@ -2280,18 +2283,25 @@ unsafe extern "C" {
 
     pub(crate) fn LLVMRustCoverageCreatePGOFuncNameVar(
         F: &Value,
-        FuncName: *const c_char,
+        FuncName: *const c_uchar, // See "PTR_LEN_STR".
         FuncNameLen: size_t,
     ) -> &Value;
-    pub(crate) fn LLVMRustCoverageHashBytes(Bytes: *const c_char, NumBytes: size_t) -> u64;
+    pub(crate) fn LLVMRustCoverageHashBytes(
+        Bytes: *const c_uchar, // See "PTR_LEN_STR".
+        NumBytes: size_t,
+    ) -> u64;
 
-    pub(crate) fn LLVMRustCoverageWriteCovmapSectionNameToString(M: &Module, OutStr: &RustString);
-
-    pub(crate) fn LLVMRustCoverageWriteCovfunSectionNameToString(M: &Module, OutStr: &RustString);
-
-    pub(crate) fn LLVMRustCoverageWriteCovmapVarNameToString(OutStr: &RustString);
+    pub(crate) safe fn LLVMRustCoverageWriteCovmapSectionNameToString(
+        M: &Module,
+        OutStr: &RustString,
+    );
+    pub(crate) safe fn LLVMRustCoverageWriteCovfunSectionNameToString(
+        M: &Module,
+        OutStr: &RustString,
+    );
+    pub(crate) safe fn LLVMRustCoverageWriteCovmapVarNameToString(OutStr: &RustString);
 
-    pub(crate) fn LLVMRustCoverageMappingVersion() -> u32;
+    pub(crate) safe fn LLVMRustCoverageMappingVersion() -> u32;
     pub(crate) fn LLVMRustDebugMetadataVersion() -> u32;
     pub(crate) fn LLVMRustVersionMajor() -> u32;
     pub(crate) fn LLVMRustVersionMinor() -> u32;

compiler/rustc_interface/src/util.rs

@@ -1,3 +1,4 @@
+use std::any::Any;
 use std::env::consts::{DLL_PREFIX, DLL_SUFFIX};
 use std::path::{Path, PathBuf};
 use std::sync::atomic::{AtomicBool, Ordering};
@@ -6,13 +7,20 @@ use std::{env, thread};
 
 use rustc_ast as ast;
 use rustc_attr_parsing::{ShouldEmit, validate_attr};
+use rustc_codegen_ssa::back::archive::ArArchiveBuilderBuilder;
+use rustc_codegen_ssa::back::link::link_binary;
 use rustc_codegen_ssa::traits::CodegenBackend;
+use rustc_codegen_ssa::{CodegenResults, CrateInfo};
+use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::jobserver::Proxy;
 use rustc_data_structures::sync;
 use rustc_errors::LintBuffer;
-use rustc_metadata::{DylibError, load_symbol_from_dylib};
-use rustc_middle::ty::CurrentGcx;
-use rustc_session::config::{Cfg, OutFileName, OutputFilenames, OutputTypes, Sysroot, host_tuple};
+use rustc_metadata::{DylibError, EncodedMetadata, load_symbol_from_dylib};
+use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
+use rustc_middle::ty::{CurrentGcx, TyCtxt};
+use rustc_session::config::{
+    Cfg, CrateType, OutFileName, OutputFilenames, OutputTypes, Sysroot, host_tuple,
+};
 use rustc_session::output::{CRATE_TYPES, categorize_crate_type};
 use rustc_session::{EarlyDiagCtxt, Session, filesearch, lint};
 use rustc_span::edit_distance::find_best_match_for_name;
@@ -316,12 +324,13 @@ pub fn get_codegen_backend(
         let backend = backend_name
             .or(target.default_codegen_backend.as_deref())
             .or(option_env!("CFG_DEFAULT_CODEGEN_BACKEND"))
-            .unwrap_or("llvm");
+            .unwrap_or("dummy");
 
         match backend {
             filename if filename.contains('.') => {
                 load_backend_from_dylib(early_dcx, filename.as_ref())
             }
+            "dummy" => || Box::new(DummyCodegenBackend),
             #[cfg(feature = "llvm")]
             "llvm" => rustc_codegen_llvm::LlvmCodegenBackend::new,
             backend_name => get_codegen_sysroot(early_dcx, sysroot, backend_name),
@@ -334,6 +343,63 @@ pub fn get_codegen_backend(
     unsafe { load() }
 }
 
+struct DummyCodegenBackend;
+
+impl CodegenBackend for DummyCodegenBackend {
+    fn locale_resource(&self) -> &'static str {
+        ""
+    }
+
+    fn name(&self) -> &'static str {
+        "dummy"
+    }
+
+    fn codegen_crate<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Box<dyn Any> {
+        Box::new(CodegenResults {
+            modules: vec![],
+            allocator_module: None,
+            crate_info: CrateInfo::new(tcx, String::new()),
+        })
+    }
+
+    fn join_codegen(
+        &self,
+        ongoing_codegen: Box<dyn Any>,
+        _sess: &Session,
+        _outputs: &OutputFilenames,
+    ) -> (CodegenResults, FxIndexMap<WorkProductId, WorkProduct>) {
+        (*ongoing_codegen.downcast().unwrap(), FxIndexMap::default())
+    }
+
+    fn link(
+        &self,
+        sess: &Session,
+        codegen_results: CodegenResults,
+        metadata: EncodedMetadata,
+        outputs: &OutputFilenames,
+    ) {
+        // JUSTIFICATION: TyCtxt no longer available here
+        #[allow(rustc::bad_opt_access)]
+        if sess.opts.crate_types.iter().any(|&crate_type| crate_type != CrateType::Rlib) {
+            #[allow(rustc::untranslatable_diagnostic)]
+            #[allow(rustc::diagnostic_outside_of_impl)]
+            sess.dcx().fatal(format!(
+                "crate type {} not supported by the dummy codegen backend",
+                sess.opts.crate_types[0],
+            ));
+        }
+
+        link_binary(
+            sess,
+            &ArArchiveBuilderBuilder,
+            codegen_results,
+            metadata,
+            outputs,
+            self.name(),
+        );
+    }
+}
+
 // This is used for rustdoc, but it uses similar machinery to codegen backend
 // loading, so we leave the code here. It is potentially useful for other tools
 // that want to invoke the rustc binary while linking to rustc as well.

compiler/rustc_target/src/spec/base/apple/mod.rs

@@ -158,12 +158,22 @@ pub(crate) fn base(
             SplitDebuginfo::Off,
         ]),
 
+        // Tell the linker that we would like it to avoid irreproducible binaries.
+        //
         // This environment variable is pretty magical but is intended for
         // producing deterministic builds. This was first discovered to be used
         // by the `ar` tool as a way to control whether or not mtime entries in
-        // the archive headers were set to zero or not. It appears that
-        // eventually the linker got updated to do the same thing and now reads
-        // this environment variable too in recent versions.
+        // the archive headers were set to zero or not.
+        //
+        // In `ld64-351.8`, shipped with Xcode 9.3, the linker was updated to
+        // read this flag too. Linker versions that don't support this flag
+        // may embed modification timestamps in binaries (especially in debug
+        // information).
+        //
+        // A cleaner alternative would be to pass the `-reproducible` flag,
+        // though that is only supported since `ld64-819.6` shipped with Xcode
+        // 14, which is too new for our minimum supported version:
+        // https://doc.rust-lang.org/rustc/platform-support/apple-darwin.html#host-tooling
         //
         // For some more info see the commentary on #47086
         link_env: Cow::Borrowed(&[(Cow::Borrowed("ZERO_AR_DATE"), Cow::Borrowed("1"))]),

compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs

@@ -1897,6 +1897,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         other: bool,
         param_env: ty::ParamEnv<'tcx>,
     ) -> bool {
+        let parent_map = self.tcx.visible_parent_map(());
         let alternative_candidates = |def_id: DefId| {
             let mut impl_candidates: Vec<_> = self
                 .tcx
@@ -1921,7 +1922,21 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                         // FIXME(compiler-errors): This could be generalized, both to
                         // be more granular, and probably look past other `#[fundamental]`
                         // types, too.
-                        self.tcx.visibility(def.did()).is_accessible_from(body_def_id, self.tcx)
+                        let mut did = def.did();
+                        if self.tcx.visibility(did).is_accessible_from(body_def_id, self.tcx) {
+                            // don't suggest foreign `#[doc(hidden)]` types
+                            if !did.is_local() {
+                                while let Some(parent) = parent_map.get(&did) {
+                                    if self.tcx.is_doc_hidden(did) {
+                                        return false;
+                                    }
+                                    did = *parent;
+                                }
+                            }
+                            true
+                        } else {
+                            false
+                        }
                     } else {
                         true
                     }

tests/ui/proc-macro/quote/not-quotable.stderr

@@ -15,8 +15,8 @@ LL |     let _ = quote! { $ip };
              Cow<'_, T>
              Option<T>
              Rc<T>
-             RepInterp<T>
-           and 25 others
+             bool
+           and 24 others
 
 error: aborting due to 1 previous error
 

tests/ui/suggestions/auxiliary/hidden-struct.rs

@@ -1,17 +1,35 @@
+// `Foo` and `Bar` should not be suggested in diagnostics of dependents
+
 #[doc(hidden)]
 pub mod hidden {
     pub struct Foo;
 }
 
 pub mod hidden1 {
     #[doc(hidden)]
-    pub struct Foo;
+    pub struct Bar;
 }
 
+// `Baz` and `Quux` *should* be suggested in diagnostics of dependents
 
 #[doc(hidden)]
-pub(crate) mod hidden2 {
-    pub struct Bar;
+pub mod hidden2 {
+    pub struct Baz;
+}
+
+pub use hidden2::Baz;
+
+#[doc(hidden)]
+pub(crate) mod hidden3 {
+    pub struct Quux;
 }
 
-pub use hidden2::Bar;
+pub use hidden3::Quux;
+
+pub trait Marker {}
+
+impl Marker for Option<u32> {}
+impl Marker for hidden::Foo {}
+impl Marker for hidden1::Bar {}
+impl Marker for Baz {}
+impl Marker for Quux {}

tests/ui/suggestions/dont-suggest-foreign-doc-hidden.rs

@@ -1,5 +1,4 @@
 //@ aux-build:hidden-struct.rs
-//@ compile-flags: --crate-type lib
 
 extern crate hidden_struct;
 
@@ -9,7 +8,20 @@ mod local {
 }
 
 pub fn test(_: Foo) {}
-//~^ ERROR cannot find type `Foo` in this scope
+//~^ ERROR [E0412]
 
 pub fn test2(_: Bar) {}
-//~^ ERROR cannot find type `Bar` in this scope
+//~^ ERROR [E0412]
+
+pub fn test3(_: Baz) {}
+//~^ ERROR [E0412]
+
+pub fn test4(_: Quux) {}
+//~^ ERROR [E0412]
+
+fn test5<T: hidden_struct::Marker>() {}
+
+fn main() {
+    test5::<i32>();
+    //~^ ERROR [E0277]
+}