Auto merge of #131958 - Zalathar:rollup-gkuk3n1, r=Zalathar

Rollup of 4 pull requests

Successful merges:

 - #131876 (compiler: Use LLVM's Comdat support)
 - #131941 (compiletest: disambiguate html-tidy from rust tidy tool)
 - #131942 (compiler: Adopt rust-analyzer impls for `LayoutCalculatorError`)
 - #131945 (rustdoc: Clean up footnote handling)

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

9 files changed, 66 insertions, 28 deletions

diff --git a/compiler/rustc_abi/src/layout.rs b/compiler/rustc_abi/src/layout.rs
index 6e1299944a0..5ce5f14ce57 100644
--- a/compiler/rustc_abi/src/layout.rs
+++ b/compiler/rustc_abi/src/layout.rs
@@ -39,7 +39,7 @@ enum NicheBias {
     End,
 }
 
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum LayoutCalculatorError<F> {
     /// An unsized type was found in a location where a sized type was expected.
     ///
@@ -56,6 +56,31 @@ pub enum LayoutCalculatorError<F> {
     EmptyUnion,
 }
 
+impl<F> LayoutCalculatorError<F> {
+    pub fn without_payload(&self) -> LayoutCalculatorError<()> {
+        match self {
+            LayoutCalculatorError::UnexpectedUnsized(_) => {
+                LayoutCalculatorError::UnexpectedUnsized(())
+            }
+            LayoutCalculatorError::SizeOverflow => LayoutCalculatorError::SizeOverflow,
+            LayoutCalculatorError::EmptyUnion => LayoutCalculatorError::EmptyUnion,
+        }
+    }
+
+    /// Format an untranslated diagnostic for this type
+    ///
+    /// Intended for use by rust-analyzer, as neither it nor `rustc_abi` depend on fluent infra.
+    pub fn fallback_fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(match self {
+            LayoutCalculatorError::UnexpectedUnsized(_) => {
+                "an unsized type was found where a sized type was expected"
+            }
+            LayoutCalculatorError::SizeOverflow => "size overflow",
+            LayoutCalculatorError::EmptyUnion => "type is a union with no fields",
+        })
+    }
+}
+
 type LayoutCalculatorResult<FieldIdx, VariantIdx, F> =
     Result<LayoutS<FieldIdx, VariantIdx>, LayoutCalculatorError<F>>;
 
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
index c2c261da79b..4075849323a 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
@@ -132,7 +132,7 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) {
             .collect::<Vec<_>>();
         let initializer = cx.const_array(cx.type_ptr(), &name_globals);
 
-        let array = llvm::add_global(cx.llmod, cx.val_ty(initializer), "__llvm_coverage_names");
+        let array = llvm::add_global(cx.llmod, cx.val_ty(initializer), c"__llvm_coverage_names");
         llvm::set_global_constant(array, true);
         llvm::set_linkage(array, llvm::Linkage::InternalLinkage);
         llvm::set_initializer(array, initializer);
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
index d7d29eebf85..4f93e6ab1e5 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
@@ -1,4 +1,5 @@
 use std::cell::RefCell;
+use std::ffi::CString;
 
 use libc::c_uint;
 use rustc_codegen_ssa::traits::{
@@ -12,6 +13,7 @@ use rustc_middle::mir::coverage::CoverageKind;
 use rustc_middle::ty::Instance;
 use rustc_middle::ty::layout::HasTyCtxt;
 use rustc_target::abi::{Align, Size};
+use rustc_target::spec::HasTargetSpec;
 use tracing::{debug, instrument};
 
 use crate::builder::Builder;
@@ -284,10 +286,10 @@ pub(crate) fn save_cov_data_to_mod<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
     cov_data_val: &'ll llvm::Value,
 ) {
-    let covmap_var_name = llvm::build_string(|s| unsafe {
+    let covmap_var_name = CString::new(llvm::build_byte_buffer(|s| unsafe {
         llvm::LLVMRustCoverageWriteMappingVarNameToString(s);
-    })
-    .expect("Rust Coverage Mapping var name failed UTF-8 conversion");
+    }))
+    .unwrap();
     debug!("covmap var name: {:?}", covmap_var_name);
 
     let covmap_section_name = llvm::build_string(|s| unsafe {
@@ -322,7 +324,8 @@ pub(crate) fn save_func_record_to_mod<'ll, 'tcx>(
     // of descriptions play distinct roles in LLVM IR; therefore, assign them different names (by
     // appending "u" to the end of the function record var name, to prevent `linkonce_odr` merging.
     let func_record_var_name =
-        format!("__covrec_{:X}{}", func_name_hash, if is_used { "u" } else { "" });
+        CString::new(format!("__covrec_{:X}{}", func_name_hash, if is_used { "u" } else { "" }))
+            .unwrap();
     debug!("function record var name: {:?}", func_record_var_name);
     debug!("function record section name: {:?}", covfun_section_name);
 
@@ -334,7 +337,9 @@ pub(crate) fn save_func_record_to_mod<'ll, 'tcx>(
     llvm::set_section(llglobal, covfun_section_name);
     // LLVM's coverage mapping format specifies 8-byte alignment for items in this section.
     llvm::set_alignment(llglobal, Align::EIGHT);
-    llvm::set_comdat(cx.llmod, llglobal, &func_record_var_name);
+    if cx.target_spec().supports_comdat() {
+        llvm::set_comdat(cx.llmod, llglobal, &func_record_var_name);
+    }
     cx.add_used_global(llglobal);
 }
 
diff --git a/compiler/rustc_codegen_llvm/src/intrinsic.rs b/compiler/rustc_codegen_llvm/src/intrinsic.rs
index bfe623e7fc3..64f1d21b438 100644
--- a/compiler/rustc_codegen_llvm/src/intrinsic.rs
+++ b/compiler/rustc_codegen_llvm/src/intrinsic.rs
@@ -787,7 +787,9 @@ fn codegen_msvc_try<'ll>(
         let tydesc = bx.declare_global("__rust_panic_type_info", bx.val_ty(type_info));
         unsafe {
             llvm::LLVMRustSetLinkage(tydesc, llvm::Linkage::LinkOnceODRLinkage);
-            llvm::SetUniqueComdat(bx.llmod, tydesc);
+            if bx.cx.tcx.sess.target.supports_comdat() {
+                llvm::SetUniqueComdat(bx.llmod, tydesc);
+            }
             llvm::LLVMSetInitializer(tydesc, type_info);
         }
 
diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index 661debbb9f1..d0034de06c7 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -646,6 +646,7 @@ unsafe extern "C" {
     pub type Attribute;
     pub type Metadata;
     pub type BasicBlock;
+    pub type Comdat;
 }
 #[repr(C)]
 pub struct Builder<'a>(InvariantOpaque<'a>);
@@ -1490,6 +1491,9 @@ unsafe extern "C" {
     pub fn LLVMSetUnnamedAddress(Global: &Value, UnnamedAddr: UnnamedAddr);
 
     pub fn LLVMIsAConstantInt(value_ref: &Value) -> Option<&ConstantInt>;
+
+    pub fn LLVMGetOrInsertComdat(M: &Module, Name: *const c_char) -> &Comdat;
+    pub fn LLVMSetComdat(V: &Value, C: &Comdat);
 }
 
 #[link(name = "llvm-wrapper", kind = "static")]
@@ -2320,7 +2324,6 @@ unsafe extern "C" {
 
     pub fn LLVMRustPositionBuilderAtStart<'a>(B: &Builder<'a>, BB: &'a BasicBlock);
 
-    pub fn LLVMRustSetComdat<'a>(M: &'a Module, V: &'a Value, Name: *const c_char, NameLen: size_t);
     pub fn LLVMRustSetModulePICLevel(M: &Module);
     pub fn LLVMRustSetModulePIELevel(M: &Module);
     pub fn LLVMRustSetModuleCodeModel(M: &Module, Model: CodeModel);
diff --git a/compiler/rustc_codegen_llvm/src/llvm/mod.rs b/compiler/rustc_codegen_llvm/src/llvm/mod.rs
index d0db350a149..b306396e15a 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/mod.rs
@@ -178,10 +178,10 @@ pub fn SetFunctionCallConv(fn_: &Value, cc: CallConv) {
 // function.
 // For more details on COMDAT sections see e.g., https://www.airs.com/blog/archives/52
 pub fn SetUniqueComdat(llmod: &Module, val: &Value) {
-    unsafe {
-        let name = get_value_name(val);
-        LLVMRustSetComdat(llmod, val, name.as_ptr().cast(), name.len());
-    }
+    let name_buf = get_value_name(val).to_vec();
+    let name =
+        CString::from_vec_with_nul(name_buf).or_else(|buf| CString::new(buf.into_bytes())).unwrap();
+    set_comdat(llmod, val, &name);
 }
 
 pub fn SetUnnamedAddress(global: &Value, unnamed: UnnamedAddr) {
@@ -217,8 +217,7 @@ pub fn set_section(llglobal: &Value, section_name: &str) {
     }
 }
 
-pub fn add_global<'a>(llmod: &'a Module, ty: &'a Type, name: &str) -> &'a Value {
-    let name_cstr = CString::new(name).expect("unexpected CString error");
+pub fn add_global<'a>(llmod: &'a Module, ty: &'a Type, name_cstr: &CStr) -> &'a Value {
     unsafe { LLVMAddGlobal(llmod, ty, name_cstr.as_ptr()) }
 }
 
@@ -252,9 +251,14 @@ pub fn set_alignment(llglobal: &Value, align: Align) {
     }
 }
 
-pub fn set_comdat(llmod: &Module, llglobal: &Value, name: &str) {
+/// Get the `name`d comdat from `llmod` and assign it to `llglobal`.
+///
+/// Inserts the comdat into `llmod` if it does not exist.
+/// It is an error to call this if the target does not support comdat.
+pub fn set_comdat(llmod: &Module, llglobal: &Value, name: &CStr) {
     unsafe {
-        LLVMRustSetComdat(llmod, llglobal, name.as_ptr().cast(), name.len());
+        let comdat = LLVMGetOrInsertComdat(llmod, name.as_ptr());
+        LLVMSetComdat(llglobal, comdat);
     }
 }
 
diff --git a/compiler/rustc_codegen_llvm/src/mono_item.rs b/compiler/rustc_codegen_llvm/src/mono_item.rs
index 02e1995620b..bf6ef219873 100644
--- a/compiler/rustc_codegen_llvm/src/mono_item.rs
+++ b/compiler/rustc_codegen_llvm/src/mono_item.rs
@@ -64,7 +64,9 @@ impl<'tcx> PreDefineCodegenMethods<'tcx> for CodegenCx<'_, 'tcx> {
         unsafe { llvm::LLVMRustSetLinkage(lldecl, base::linkage_to_llvm(linkage)) };
         let attrs = self.tcx.codegen_fn_attrs(instance.def_id());
         base::set_link_section(lldecl, attrs);
-        if linkage == Linkage::LinkOnceODR || linkage == Linkage::WeakODR {
+        if (linkage == Linkage::LinkOnceODR || linkage == Linkage::WeakODR)
+            && self.tcx.sess.target.supports_comdat()
+        {
             llvm::SetUniqueComdat(self.llmod, lldecl);
         }
 
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index 72b03fa0560..910c27da954 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -1658,16 +1658,6 @@ extern "C" void LLVMRustPositionBuilderAtStart(LLVMBuilderRef B,
   unwrap(B)->SetInsertPoint(unwrap(BB), Point);
 }
 
-extern "C" void LLVMRustSetComdat(LLVMModuleRef M, LLVMValueRef V,
-                                  const char *Name, size_t NameLen) {
-  Triple TargetTriple = Triple(unwrap(M)->getTargetTriple());
-  GlobalObject *GV = unwrap<GlobalObject>(V);
-  if (TargetTriple.supportsCOMDAT()) {
-    StringRef NameRef(Name, NameLen);
-    GV->setComdat(unwrap(M)->getOrInsertComdat(NameRef));
-  }
-}
-
 enum class LLVMRustLinkage {
   ExternalLinkage = 0,
   AvailableExternallyLinkage = 1,
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index 82e11a3afce..f4b45a08195 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -2515,6 +2515,13 @@ fn add_link_args(link_args: &mut LinkArgs, flavor: LinkerFlavor, args: &[&'stati
 }
 
 impl TargetOptions {
+    pub fn supports_comdat(&self) -> bool {
+        // XCOFF and MachO don't support COMDAT.
+        !self.is_like_aix && !self.is_like_osx
+    }
+}
+
+impl TargetOptions {
     fn link_args(flavor: LinkerFlavor, args: &[&'static str]) -> LinkArgs {
         let mut link_args = LinkArgs::new();
         add_link_args(&mut link_args, flavor, args);