Auto merge of #131111 - matthiaskrgr:rollup-n6do187, r=matthiaskrgr

Rollup of 4 pull requests

Successful merges:

 - #130005 (Replace -Z default-hidden-visibility with -Z default-visibility)
 - #130229 (ptr::add/sub: do not claim equivalence with `offset(c as isize)`)
 - #130773 (Update Unicode escapes in `/library/core/src/char/methods.rs`)
 - #130933 (rustdoc: lists items that contain multiple paragraphs are more clear)

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

Author: bors

Diff for: compiler/rustc_codegen_gcc/src/allocator.rs

@@ -104,10 +104,17 @@ fn create_wrapper_function(
         false,
     );
 
-    if tcx.sess.default_hidden_visibility() {
-        #[cfg(feature = "master")]
-        func.add_attribute(FnAttribute::Visibility(gccjit::Visibility::Hidden));
+    #[cfg(feature = "master")]
+    match tcx.sess.default_visibility() {
+        rustc_target::spec::SymbolVisibility::Hidden => {
+            func.add_attribute(FnAttribute::Visibility(gccjit::Visibility::Hidden))
+        }
+        rustc_target::spec::SymbolVisibility::Protected => {
+            func.add_attribute(FnAttribute::Visibility(gccjit::Visibility::Protected))
+        }
+        rustc_target::spec::SymbolVisibility::Interposable => {}
     }
+
     if tcx.sess.must_emit_unwind_tables() {
         // TODO(antoyo): emit unwind tables.
     }

Diff for: compiler/rustc_codegen_llvm/src/allocator.rs

@@ -77,18 +77,20 @@ pub(crate) unsafe fn codegen(
         // __rust_alloc_error_handler_should_panic
         let name = OomStrategy::SYMBOL;
         let ll_g = llvm::LLVMRustGetOrInsertGlobal(llmod, name.as_ptr().cast(), name.len(), i8);
-        if tcx.sess.default_hidden_visibility() {
-            llvm::LLVMRustSetVisibility(ll_g, llvm::Visibility::Hidden);
-        }
+        llvm::LLVMRustSetVisibility(
+            ll_g,
+            llvm::Visibility::from_generic(tcx.sess.default_visibility()),
+        );
         let val = tcx.sess.opts.unstable_opts.oom.should_panic();
         let llval = llvm::LLVMConstInt(i8, val as u64, False);
         llvm::LLVMSetInitializer(ll_g, llval);
 
         let name = NO_ALLOC_SHIM_IS_UNSTABLE;
         let ll_g = llvm::LLVMRustGetOrInsertGlobal(llmod, name.as_ptr().cast(), name.len(), i8);
-        if tcx.sess.default_hidden_visibility() {
-            llvm::LLVMRustSetVisibility(ll_g, llvm::Visibility::Hidden);
-        }
+        llvm::LLVMRustSetVisibility(
+            ll_g,
+            llvm::Visibility::from_generic(tcx.sess.default_visibility()),
+        );
         let llval = llvm::LLVMConstInt(i8, 0, False);
         llvm::LLVMSetInitializer(ll_g, llval);
     }
@@ -132,9 +134,11 @@ fn create_wrapper_function(
             None
         };
 
-        if tcx.sess.default_hidden_visibility() {
-            llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Hidden);
-        }
+        llvm::LLVMRustSetVisibility(
+            llfn,
+            llvm::Visibility::from_generic(tcx.sess.default_visibility()),
+        );
+
         if tcx.sess.must_emit_unwind_tables() {
             let uwtable =
                 attributes::uwtable_attr(llcx, tcx.sess.opts.unstable_opts.use_sync_unwind);

Diff for: compiler/rustc_codegen_llvm/src/declare.rs

@@ -22,6 +22,7 @@ use tracing::debug;
 use crate::abi::{FnAbi, FnAbiLlvmExt};
 use crate::context::CodegenCx;
 use crate::llvm::AttributePlace::Function;
+use crate::llvm::Visibility;
 use crate::type_::Type;
 use crate::value::Value;
 use crate::{attributes, llvm};
@@ -84,11 +85,7 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
         fn_type: &'ll Type,
     ) -> &'ll Value {
         // Declare C ABI functions with the visibility used by C by default.
-        let visibility = if self.tcx.sess.default_hidden_visibility() {
-            llvm::Visibility::Hidden
-        } else {
-            llvm::Visibility::Default
-        };
+        let visibility = Visibility::from_generic(self.tcx.sess.default_visibility());
 
         declare_raw_fn(self, name, llvm::CCallConv, unnamed, visibility, fn_type)
     }
@@ -107,11 +104,7 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
         unnamed: llvm::UnnamedAddr,
         fn_type: &'ll Type,
     ) -> &'ll Value {
-        let visibility = if self.tcx.sess.default_hidden_visibility() {
-            llvm::Visibility::Hidden
-        } else {
-            llvm::Visibility::Default
-        };
+        let visibility = Visibility::from_generic(self.tcx.sess.default_visibility());
         declare_raw_fn(self, name, callconv, unnamed, visibility, fn_type)
     }
 

Diff for: compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -4,6 +4,7 @@
 use std::marker::PhantomData;
 
 use libc::{c_char, c_int, c_uint, c_ulonglong, c_void, size_t};
+use rustc_target::spec::SymbolVisibility;
 
 use super::RustString;
 use super::debuginfo::{
@@ -133,6 +134,16 @@ pub enum Visibility {
     Protected = 2,
 }
 
+impl Visibility {
+    pub fn from_generic(visibility: SymbolVisibility) -> Self {
+        match visibility {
+            SymbolVisibility::Hidden => Visibility::Hidden,
+            SymbolVisibility::Protected => Visibility::Protected,
+            SymbolVisibility::Interposable => Visibility::Default,
+        }
+    }
+}
+
 /// LLVMUnnamedAddr
 #[repr(C)]
 pub enum UnnamedAddr {

Diff for: compiler/rustc_interface/src/tests.rs

@@ -770,7 +770,7 @@ fn test_unstable_options_tracking_hash() {
     tracked!(crate_attr, vec!["abc".to_string()]);
     tracked!(cross_crate_inline_threshold, InliningThreshold::Always);
     tracked!(debug_info_for_profiling, true);
-    tracked!(default_hidden_visibility, Some(true));
+    tracked!(default_visibility, Some(rustc_target::spec::SymbolVisibility::Hidden));
     tracked!(dep_info_omit_d_target, true);
     tracked!(direct_access_external_data, Some(true));
     tracked!(dual_proc_macros, true);

Diff for: compiler/rustc_middle/src/mir/mono.rs

@@ -15,6 +15,7 @@ use rustc_query_system::ich::StableHashingContext;
 use rustc_session::config::OptLevel;
 use rustc_span::Span;
 use rustc_span::symbol::Symbol;
+use rustc_target::spec::SymbolVisibility;
 use tracing::debug;
 
 use crate::dep_graph::{DepNode, WorkProduct, WorkProductId};
@@ -305,6 +306,16 @@ pub enum Visibility {
     Protected,
 }
 
+impl From<SymbolVisibility> for Visibility {
+    fn from(value: SymbolVisibility) -> Self {
+        match value {
+            SymbolVisibility::Hidden => Visibility::Hidden,
+            SymbolVisibility::Protected => Visibility::Protected,
+            SymbolVisibility::Interposable => Visibility::Default,
+        }
+    }
+}
+
 impl<'tcx> CodegenUnit<'tcx> {
     #[inline]
     pub fn new(name: Symbol) -> CodegenUnit<'tcx> {

Diff for: compiler/rustc_monomorphize/src/partitioning.rs

@@ -904,26 +904,22 @@ fn mono_item_visibility<'tcx>(
 }
 
 fn default_visibility(tcx: TyCtxt<'_>, id: DefId, is_generic: bool) -> Visibility {
-    if !tcx.sess.default_hidden_visibility() {
-        return Visibility::Default;
-    }
-
-    // Generic functions never have export-level C.
-    if is_generic {
-        return Visibility::Hidden;
-    }
-
-    // Things with export level C don't get instantiated in
-    // downstream crates.
-    if !id.is_local() {
-        return Visibility::Hidden;
-    }
+    let export_level = if is_generic {
+        // Generic functions never have export-level C.
+        SymbolExportLevel::Rust
+    } else {
+        match tcx.reachable_non_generics(id.krate).get(&id) {
+            Some(SymbolExportInfo { level: SymbolExportLevel::C, .. }) => SymbolExportLevel::C,
+            _ => SymbolExportLevel::Rust,
+        }
+    };
+    match export_level {
+        // C-export level items remain at `Default` to allow C code to
+        // access and interpose them.
+        SymbolExportLevel::C => Visibility::Default,
 
-    // C-export level items remain at `Default`, all other internal
-    // items become `Hidden`.
-    match tcx.reachable_non_generics(id.krate).get(&id) {
-        Some(SymbolExportInfo { level: SymbolExportLevel::C, .. }) => Visibility::Default,
-        _ => Visibility::Hidden,
+        // For all other symbols, `default_visibility` determines which visibility to use.
+        SymbolExportLevel::Rust => tcx.sess.default_visibility().into(),
     }
 }
 

Diff for: compiler/rustc_session/src/config.rs

@@ -3008,7 +3008,8 @@ pub(crate) mod dep_tracking {
     use rustc_span::edition::Edition;
     use rustc_target::spec::{
         CodeModel, FramePointer, MergeFunctions, OnBrokenPipe, PanicStrategy, RelocModel,
-        RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, TargetTriple, TlsModel, WasmCAbi,
+        RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, SymbolVisibility, TargetTriple,
+        TlsModel, WasmCAbi,
     };
 
     use super::{
@@ -3101,6 +3102,7 @@ pub(crate) mod dep_tracking {
         StackProtector,
         SwitchWithOptPath,
         SymbolManglingVersion,
+        SymbolVisibility,
         RemapPathScopeComponents,
         SourceFileHashAlgorithm,
         OutFileName,

Diff for: compiler/rustc_session/src/options.rs

@@ -13,8 +13,8 @@ use rustc_span::edition::Edition;
 use rustc_span::{RealFileName, SourceFileHashAlgorithm};
 use rustc_target::spec::{
     CodeModel, FramePointer, LinkerFlavorCli, MergeFunctions, OnBrokenPipe, PanicStrategy,
-    RelocModel, RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, TargetTriple, TlsModel,
-    WasmCAbi,
+    RelocModel, RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, SymbolVisibility,
+    TargetTriple, TlsModel, WasmCAbi,
 };
 
 use crate::config::*;
@@ -416,6 +416,8 @@ mod desc {
         "one of: `disabled`, `trampolines`, or `aliases`";
     pub(crate) const parse_symbol_mangling_version: &str =
         "one of: `legacy`, `v0` (RFC 2603), or `hashed`";
+    pub(crate) const parse_opt_symbol_visibility: &str =
+        "one of: `hidden`, `protected`, or `interposable`";
     pub(crate) const parse_src_file_hash: &str = "either `md5` or `sha1`";
     pub(crate) const parse_relocation_model: &str =
         "one of supported relocation models (`rustc --print relocation-models`)";
@@ -922,6 +924,20 @@ mod parse {
         true
     }
 
+    pub(crate) fn parse_opt_symbol_visibility(
+        slot: &mut Option<SymbolVisibility>,
+        v: Option<&str>,
+    ) -> bool {
+        if let Some(v) = v {
+            if let Ok(vis) = SymbolVisibility::from_str(v) {
+                *slot = Some(vis);
+            } else {
+                return false;
+            }
+        }
+        true
+    }
+
     pub(crate) fn parse_optimization_fuel(
         slot: &mut Option<(String, u64)>,
         v: Option<&str>,
@@ -1688,8 +1704,8 @@ options! {
         "compress debug info sections (none, zlib, zstd, default: none)"),
     deduplicate_diagnostics: bool = (true, parse_bool, [UNTRACKED],
         "deduplicate identical diagnostics (default: yes)"),
-    default_hidden_visibility: Option<bool> = (None, parse_opt_bool, [TRACKED],
-        "overrides the `default_hidden_visibility` setting of the target"),
+    default_visibility: Option<SymbolVisibility> = (None, parse_opt_symbol_visibility, [TRACKED],
+        "overrides the `default_visibility` setting of the target"),
     dep_info_omit_d_target: bool = (false, parse_bool, [TRACKED],
         "in dep-info output, omit targets for tracking dependencies of the dep-info files \
         themselves (default: no)"),

Diff for: compiler/rustc_session/src/session.rs

@@ -31,7 +31,8 @@ use rustc_span::{FileNameDisplayPreference, RealFileName, Span, Symbol};
 use rustc_target::asm::InlineAsmArch;
 use rustc_target::spec::{
     CodeModel, DebuginfoKind, PanicStrategy, RelocModel, RelroLevel, SanitizerSet,
-    SmallDataThresholdSupport, SplitDebuginfo, StackProtector, Target, TargetTriple, TlsModel,
+    SmallDataThresholdSupport, SplitDebuginfo, StackProtector, SymbolVisibility, Target,
+    TargetTriple, TlsModel,
 };
 
 use crate::code_stats::CodeStats;
@@ -617,12 +618,13 @@ impl Session {
         }
     }
 
-    /// Whether the default visibility of symbols should be "hidden" rather than "default".
-    pub fn default_hidden_visibility(&self) -> bool {
+    /// Returns the default symbol visibility.
+    pub fn default_visibility(&self) -> SymbolVisibility {
         self.opts
             .unstable_opts
-            .default_hidden_visibility
-            .unwrap_or(self.target.options.default_hidden_visibility)
+            .default_visibility
+            .or(self.target.options.default_visibility)
+            .unwrap_or(SymbolVisibility::Interposable)
     }
 }